:I .. tD z I ' , i I' oEpA R T M E N T oF T " E A R ~ 1 r :r ri Ec " N 1 cAL M A N uA L 11 1 I ! : jl i ~.' I I I I ' I ' II I'i I t ~~ ' :·, ll ' ' I'· l j I I I :1 ~ I I !>\~\. \\ ·. S '5-50S : r I I' I ' !. ' ' 'i i 1 · !, I i! I ' ! : I .. : ., . !1, •.·. •,, ! II'! II ' I MARINE 8~lVAGE 1 I ' I' I''I.'. I~. I II ' I: ::, I I . · AND.I~ , .• ~ I : 11 11 '1, :': i\ iII HULL REPAIR II :: ;; ~ I I I· . 'r' :: I' ' ', , r ·~ ~ I ; 1 '': : ) I ~ ' HEADQUARTERS, DEPARTMENT OF THE ARMY : i : . ~ ' : ~: J! ::a I 1 JULY 1966::•.: TAGO 5244A 'I i· I:,, i i 1! 1 ·i 1!1: , I 1·11' i . H I' illl I! !Ill TM 55-503 TECHNICAL MANUAL} HEADQUARTERS DEPARTMENT OF THE ARMY No. 55-503 WASHINGTON, D.C., 13 July 1966 MARINE SALVAGE AND HULL REPAIR Paragraph Page CHAPTER 1. INTRODUCTION SECTION I. General-------------------------------------------------------------------· 1-5 3 II. Types of vessels------------------------------------------------------------6-10 7 III. Tools----------------------------------------------------------------------11-17 10 IV. Reading and interpreting blueprints-----------------------------------~~-----18-24 14 CHAPTER 2. HULL STRUCTURES SECTION I. Types of hulls--------------~----------------------------------~----~-------25-28 21 II. Strength requirements-----------------------------------------------------· 29-32 23 III. Hull components------------·------------------------------------------------33-49 29 Superstructures:..________________________________.___________________________ IV. 50-57 54 v. Corrosion, dry rot, mildew, decay, and electrolysis _____________________________ _ 58-62 56 Deck coverings ____________________________________________________________ _ VI. 63-80 63 CHAPTER 3. MARINE SALVAGE, DOCKING, AND HAUL OUT SECTION I. Salvageprocedures---------------------------------------------------------81-90 81 II. Damage controL-----------------------------------------------------------· 91-111 83 III. Haul out procedures--------------------------------------------------------· 112-115 128 IV. Cleaning and inspection-----·------------------------------------------------116, 117 128 v. Storageprocedures---------------------------------------------------------· 118-121 130 CHAPTER 4. WOOD HULL REPAIR SECTION I. General information--------------------------------------------------------· 122,123 139 II. Repairing wood hulls--------------------------------------------------------124-147 140 III. Calking---------------------------------------~---------------------------· 148-150 171 IV. Bedding compounds----------------~----------------------------------------151, 152 172 v. Preserving and finishing wood surfaces---------------------------------------· 153-157 173 CHAPTER 5. STEEL HULL REPAIR SECTION I. General information________________________________________________________ 158-161 177 II. Repairing steel hulls--------------------------------------------------------162-165 179 III. Preserving and finishing steel surfaces----------------------------------------166-168 189 CHAPTER 6. PLASTIC HULL REPAIR SECTION I. General information--------------------------------------------------------169-172 195 II. Repairprocedures-----------------------------------~--------------~-------173-180 196 CHAPTER 7. ALUMINUM HULL REPAIR SECTION I. General information-------------------·-------------------------------------· 181, 182 201 II. Repair procedures----------------------------------------------------------183-188 201 CHAPTER 8. STEERING SYSTEMS-----------------------------------~-------------~---189-198 207 CHAPTER 9. PROPELLERS AND SHAFTS SECTION I. Propellers----------------------------------------------------------------199-209 223 II. Propeller shafts and bearings-------------------------------------------'-----210-216 231 III. Control of electrolysis-------------------------------------------------------217-220 248 CHAPTER 10. MACHINERY FOUNDATIONS SECTION I. Introduction--------------------------------------------------------------· 221, 222 250 · II. Main engine foundation-----------------------------------------------------223-228 250 III. Auxiliary equiptnenL-------------------------------------------------------229-231 254 AGO 61!UA 1 / Parasrapb P-.e CHAPTER 11. WATERTIGHT INTEGRITY SECTION I. Tests and inspections-------------------------------------------------------· 232-234 257 II. Bulkheads and hatches_______________________________________________________ 235, 236 258 III. Airports, portlights, and skylights--------------------------------------------237, 238 261 CHAPTER 12. SPARS AND RIGGING, AND BOAT DAVITS SECTION I. Spars and rigging----------------------------------------------------------239-247 265 268 II. Boat davits----------------------------------------------------------------248-253 CHAPTER 13. GROUND TACKLE SECTION I. Anchors----------------~--------------------------------------------------254,255 273 II. Anchor cable (chain)-----------------------------------------------·--------· 256-258 274 259-262 278 III. Anchorvnndlasses~--------------------------------------------------------- CHAPTER 14. DECK AND HULL FITTINGS SECTION I. Deck fittings---------------------------------------------------------------263-266 284 II. Hull fittings----------------------------------------------------------------267-269 290 CHAPTER 15. PIPING ·sYSTEMS SECTION I. General information--------------------------------------------------------270-274 297 II. Methods of joining----------------------------------------------------------275-282 298 III. Threaded connections-------------------------------------------------------283-287 305 IV. Pipe hangers and supports---------------------------------------------------288-293 309 V. Bends in pipe and tubing____________________________________________________ 294, 295 310 VI. Repair of piping------------------------------------------------------------296-301 312 315 VII. Valves--------------------------------------------------------------------·· 302-304 VIII. Stearntraps----------------------------------------------------------------305-308 327 IX. Strainers, separators, and filters______________________________________________ 309-313 330 CHAPTER 16. PAINTING, MARKING, AND INSIGNIA SECTION I. Painting-------------------------------------------------------------------314-316 335 II. Marking and insignia location layouL-----------------------------------------· 317-321 339 CHAPTER 17. REPAIR SPECIFICATIONS-------------------------------------------------322, 323 340 APPENDIX I. REFERENCES------------------· -----------------------------------------364 366 II. TABLES OF COMMON MATERIALS AND FASTENINGS-------------------· 394 III. DOCKING PLANS FOR STANDARD ARMY VESSELS----------------------· 423 IV. CONVERSION TABLES---------------------------------------------------· 433 GLOSSARY GLOSSARY--------------------------------------------------------------449 INDEX AGO 6244A CHAPTER 1 INTRODUCTION Section I. GENERAL 1. Purpose and Scope a. This manual provides a ready reference and training guide for personnel engaged in the salvage and repair of marine hulls and related equipment. b. Appendixes include tables of common materials and fastenings, docking plans for standard Army vessels, conversion tables, and a glossary of construction and repair terms. c. The material presented is applicable to nuclear and nonnuclear warfare. d. Users of this manual are encouraged to submit recommended changes or comments to improve this manual. Comments should be keyed to the specific page, paragraph, and line of the text in which the change is recommended. Reason should be provided for each comment to insure understanding and complete evalua tion. Comments should be forwarded on DA Form 1598 (Record of Comments on Publications) direct to the Commandant, U.S. Army Transportation School, ATTN: ODL, Fort Eustis, Va. 23604. 2. Hull Repair Categories Repairs to floating craft and amphibian hulls are classified as temporary or permanent. a. Temporary. Temporary repairs are those repaius made to a damaged hull to retain or restore its structural strength and watertight integrity until permanent repairs are feasible. i. Permanent. Permanent repairs are those repairs made to a damaged hull to restore its structural strength and watertight integrity in order to insure the safety of the craft and personnel and to insure the capability of the craft to accomplish assigned missions. AGO 6244A 3. Maintenance Categories a. General. Maintenance operations are assigned to specific levels of command in accordance with the primary mission, special characteristics and mobility of the level involved, and economical distribution of resources available. (1) Organization maintenance. The maintenance normally authorized for, performed by, and the responsibility of a using organization on equipment in its possession. This level of maintenance is determined by the capabilities of authorized personnel, skills,. tools, parts supply, and test equipment as prescribed in appropriate Department of the Army TOE or TD. This type of maintenance was formerly known as first and second echelon maintenance. (2) Direct support maintenance. That maintenance normally authorized and performed by designated maintenance activities in direct support of using organizations. This category of maintenance is limited to repair of end items or unserviceable assemblies in support of using organizations on a return-to-user basis. ( 3) General support maintenance. That maintenance authorized and performed by designated TOE and TD organizations in support of the Army supply system. These organizations will repair or overhaul material to required maintenance standards in ready-to-issue condition. (4) Depot maintenance. Depot maintenance activities which, through overhaul of economically repairable mate rial, augment the procurement an individual maintenance manual listprogram in satisfying overall Army ing these various functions. requirements. These activities provide (2) Unscheduled maintenance. That mainfor repair of material beyond the tenance which has not been anticicapability .of general support maintepated, such as accidental damage, colnance organizations. lision, internal or external explosion, and battle damage. This category also b. Repair Limitations. includes such on-the-spot inspections (1) Maintenance will be performed in acas may be directed by competentcordance with established maintenance authority.doctrine at the lowest category consistent with the tactical situation, 4. Hull Repairman Requirements skills, time, repair parts, tools, and a. Organization. Marine hull repair personneltest equipment available within allocaare authorized to certain organizations by TOE. tions. These personnel usually consist of an officer (2) Repairs will be accomplished on site, or noncommissioned officer, plus a number ofwhen feasible, and in accordance with skilled personnel to accomplish the huh repair maintenance allocation charts. mission. The complement of personnel is based (3) Unserviceable material which is beon the number and types of floating craft or yond the maintenance capability of amphibians supported. an organization will be reported or b. Personnel. Personnel in the hull repairdelivered to the next higher maintesection of a maintenance organization are renance organization. quired to have several special skills. The special (4) All authorized maintenance within the skills and duties in the appropriate classificacapability of an organization will be tion are listed below. accomplished, when possible, before (1) Marine Hull Repairman (MOS 44K)evacuation of economically repairable (563). Must be experienced in repairitems to the next higher maintenance ing and supervising repairs to hulls,organization. Higher categories will superstructures, and internal structur perform the maintenance functions of al elements of steel, aluminum, plastic,lower categories when required or dior wood floating craft and amphibians. rected by the appropriate commander. (a) Assists in constructing and erecting (5) Controlled cannibalization, as a source scaffolding and wooden frames to of obtaining repair parts and assemfacilitate repairs to hulls and interblies to support maintenance of equipnal structures. ment, will be used as prescribed in (b) Measures, cuts, shapes, and notches AR750-50. lumber to build parts for repair of keels, ribs, masts, gunwales, and (6) Repairs will be accomplished under bulkheads. the Inspect and Repair Only As Neces (c) Fabricates and positions structuralsary (IROAN) principle at organizaparts for repairs to bulkheads,tional and direct support levels of frames, plates, doors, and brackets. command. (d) Operates and maintains power c. Scheduled and Unscheduled Maintenance. driven saws, drills, presses, shapers, planers, and other machinery used (1) Scheduled maintenance. That mainte in repairs of steel, aluminum,nance which is required periodically on plastic, and wood materials. a continuing basis. This includes, but is not limited to, daily, weekly, month(e) Requisitions supplies, tools, and ly, and annual inspections and mainmachinery. tenance tests. Each type of vessel has (f) Coordinates with shipwrights and AGO 11244A 4 shipfitters in assigning duties, and machines used are complex in operation, scheduling work, determining job specific safety precautions are prescribed as priorities, preparing repair work follows: orders, and inspecting completed repairs. (g) Prepares technical reports. (k) Conducts and supervises on-the-job training programs. (2) Diver (MOS OOB) (564). Must be well experienced in performing underwater repair, salvage, and demolition duties. (a) Inspects diving suit and operates and tests air hose, life lines, and telephone to determine condition and serviceability. (b) Descends to underwater work area, examines object to be worked upon, and determines which tools, materials, and equipment are required to accomplish assigned mission. (c) Repairs submerged sections of vessels by . calking seams, patching rips and punctures in hulls, clearing fouled propellers and rudders, and fitting and securing prefabricated parts in position. (d) Assists in construction of underwater sections of piers and rigging for surfacing a vessel or equipment that is submerged. (e) Prepares explosive charges and detonation wires for demolishing piers, sunken vessels, and material formations to facilitate clearing harbor channels and removing hazards to safe navigation. (f) Maintains diving log. (g) Must· know usage and method of lowering such equipment, as pneumatic chain saw, rock drill, nail driver, and drill. (k) Must have fundamental knowledge of causes and treatment of air embolism, bends, squeezes, asphyxia, and bleeding, due to decompression. 5. Safety Precautions One of the first considerations in planning any maintenance or repair is safety to personnel and equipment. Because many of the tools a. Compressed Gases. Cylinders, regulators, hoses, and torches are components of shop equipment for heating, welding, and cutting. It is important to know and observe the following safety rules: (1) Do not fill a cylinder with a gas other than the one for which it is specifically designated, and never remove or change the labeling decals. (2) Close values and put protective caps in place on all empty cylinders. (3) Do not drop cylinders or allow them to strike against each other. ( 4) Do not use cylinders as rollers or supports. (5) Do not hammer or strike the valve wheel to open or close a valve; use only the approved tool or wrench for this purpose. (6) Use warm, not boiling, water to free a valve outlet if it is iced over. (7) Do not use a cylinder that is improperly marked. (8) Do not use a lifting magnet or sling to handle a cylinder. (9) Do not mix full and empty cylinders in a storage rack. (10) Do not tamper or try to adjust safety devices on valves or cylinders. ( 11) Do not store oxygen and acetylene cylinders in the same immediate area. b. Oxyacetylene Torch. (1) Avoid use of any lubricant, oil or grease, on any oxyacetylene equipment. (2) Use friction lighters or stationary pilot flame to light torch. The use of matches can cause serious hand burns. (3) Light torch with the acetylene valve partially open and the oxygen valve closed. ;(} (4) ·Do not weld or cut material in cramped or inadequate quarters. Hot sparks or metal can make contact with arms, legs, or flammable materials. ( 5) Purge system thoroughly of air to prevent backfire and flashback before lighting torch. ( 6) Protect wooden decks and floors from hot metal by the use of asbestos fabrics or sand. {7) Remove all inflammable material, such as cotton, waste, oil, gasoline, and scrap wood, from the vicinity of welding. When welding a bulkhead remove inflammables from both sides of bulkhead. (8) Warn all personnel in the vicinity, not protected by proper clothing and goggles, to stay clear of the welding operations. (9) Remove assembled parts that could become warped or otherwise damaged by the welding process. (10) Do not leave hot, rejected electrode studs, steel scraps, or tools on the floor about the welding equipment. These could cause accidents. ( 11) Keep a suitable fire extinguisher conveniently located at all times. Establish fire watches as necessary. (12) Wear protective clothing such as asbestos aprons or jackets, flameproof· gloves, cuffiess trousers, and combat type boots during welding operations. (13) Use protective equipment such as goggles, spectacles, and helmet or hand type face shield. (14) Do not permit unauthorized personnel to use oxyacetylene welding or cutting equipment. ( 15) Do not leave the torch when not in use and close valves tightly. (16) Do not weld a closed fuel tank or container until every precaution has been taken to eliminate all confined gases, fumes, and dust from inside and outside the tank or container area. c. Machine Tools. (1) Do not lean against any machine that is in motion. Keep clear of gears, belts, or any other moving part. Never remove the guards from any part of a machine in operation. {2) Do not start a machine unless familiar with its proper operation. (3) Do not attempt to clean, adjust, or repair a machine while it is in operation. (4) Protect eyes at all times with safety goggles if there is any possibility of flying particles of metal. (5) Keep fingers away from cutting edges always when a machine is in operation. ( 6) Do not wear loosely hanging clothes around machines. d. Circular Saw. ( 1) Keep blade clean always. Do not allow grime or resin to accumulate on blade. (2) Do not use a dull blade or one that lacks set or clearance. (3) Use a push stick always when ripping narrow pieces. ( 4) Do not attempt to adjust the ripping fence or cutoff gage while the blade is revolving. (5) Do not reach across the blade for any reason. (6) Pull main switch when cleaning the saw table of scrap or stock. (7) Lower blade below the table surface always when the machine is not to be used immediately. e. Jointer. ( 1) Keep hands on top of the board and shift them while pushing the board along, so that hands are never directly over the cutterhead. (2) Keep jointer deck and infeed bed clear of chips, blocks, and sawdust. (3) Do not use jointing boards which contain loose knots. (4) Do not attempt to adjust the setting of the cutterhead knifes unless experienced. f. Wood Lathe. (1) Have jacket or shirt sleeves buttoned or rolled above elbows. (2) Wear goggles when doing turning jobs. AGO 62UA (3) Ascertain that stock to be worked is securely mounted on the face plate or between the centers. ( 4) Do not allow anyone to stand behind a lathe that is in operation. ( 5) A void using excessive speeds, using only sufficient speed to accomplish a good turning job. g. Subme1·sible Pum ps. ( 1) Keep handling line, electric cable, and discharge hose clear of obstructions so the pump can be removed quickly. Keep hose free of kinks. (2) Use a strainer always. (3) Keep suction lift and discharg~ head as low as possible. (4) Keep suction end of the pump or end of the suction hose in the water while the pump is operating. (5) Do not use an electric submersible pump if explosive fumes are present. h. Plastic Materials. ( 1) Provide forced intake and exhaust ventilation when plastic materials are being worked. (2) Wear long sleeve coveralls, neoprene gloves, knee-high rubber boots, and goggles. (3) Wash hands frequently. ( 4) A void spilling plastic materials. Keep kraft paper in areas where material is likely to spill or drip. (5) Keep resin and activator off skin areas by using protective ointment. If contaminated, flush immediately with water for at least 15 minutes while awaiting medical treatment. (6) Wash gloves and goggles with a good detergent after each use. Section II. TYPES OF VESSELS 6. General U.S. Army Transportation Corps vessels consist of floating craft, landing craft, and amphibians. A typical example of each is shown in figure 1. 7. Floating Craft Floating craft include barges, tugs, pickets, cargo and passenger vessels, maintenance craft, and liquid cargo vessels. Capabilities and uses of floating craft are as follows: a. Barge, Deck Car go, N onpropelled, Steel, 585 Tons, 120 F eet , Design 231A. This craft transports wheeled and tracked vehicles and heavy general cargo in harbors and on inland waters, or it can be towed overseas. This vessel can be towed at a speed of 8 knots, which is faster than most barges of comparable size can be towed. b. Boat, Passenger and Car go, Diesel, Steel, 65 Feet 6/nches Design 2001. This vessel transports small groups of passengers and light cargo in harbors and on inland waters. It can also be used for firefighting, salvage operations, and inspections. A "T" designation is normally AGO 5244A applied to freight supply vessels under 100 feet in length, and to general utility craft sometimes used for command purposes or limited towing missions. c. Boat, Picket, Diesel, Steel, 46 Feet 41/2 Inches, D esign 4003. This small passenger launch and liaison craft, called a J-boat, is used for ferrying service, security patrols, and inspections. This type vessel is transported overseas aboard a larger vessel. d. Boat, Picket , Diesel, Wood, 64 Feet 11 Inches, Design 4002. This picket boat, called a Q-boat, serves as a patrol or command and inspection craft in harbors and inland waters. It is also suitable for offshore patrolling, towing targets, and intelligence work. In addition, this craft is used in tropic and arctic operations and special missions in hydrographic surveys. This vessel is transported overseas on the deck of a freighter. e. Repair Shop, Floating, Marine Equipment, Nonpropelled, Steel, 210 Feet, Design 7011. The floating repair shop is used for performing depot maintenance in harbors and on inland waters, particularly where marine repair facili 7 Figure 1. cD Floating cr aft-tug (design 3006). ties are inadequate or nonexistent. This vessel is authorized a crew of 26, not including the repair personnel aboard. f. Tug, Harbor, Diesel, 200-Horsepower, Steel, 45 Feet, Design 320. Harbor craft units use this craft to tow barges in harbors and on iniand waterways. It can also be used in beach operations where sectional steel piers or pontoon cuaseways have been constructed. Additional uses inelude target towing, refueling, and salvage work. They are deckloaded aboard a larger vessel for transport overseas. g. "Tug, Harbor, Diesel, 600-Horsepower, Steel, 65 Feet, Design 3004. This craft is used to move nonpropelled barges in ports and harbors and also to berth oceangoing vessels. It has firefighting and salvage equipment aboard. It is transported overseas on the deck of a freighter. h. Tug, Harbor, Diesel, 1,200-Horsepower, Steel, 100 Feet, Design 3006. This large steel tug is used primarily to berth and unberth large cargo vessels and tow heavy loads within harbor areas. Secondary tasks of this vessel include general utility uses, salvage work, and AGO 5244A Figure 1. ®Landing cra/t-(LCM-8). Figure 1.@ Amphibian-(Lark-V). firefighting. This vessel can travel overseas under its own power. i. Vessel, Liquid Cargo, Diesel, Steel, 11,500 Barrels, 210 Feet-; Design 7014. This tanker transports liquid cargo, such as petroleum, oil, lubricants, and water, to airfields and outlying bases. A "Y" designation is normally applied AGO 6244A to all self-propelled liquid cargo vessels, regardless of size. This craft is highly maneuverable, allowing it to operate in restricted waters such as harbors without the need for tugs for berthing and unberthing. This vessE-l can travel overseas under its own power. j. Crane, Barge, Diese"t-Electric, Revolving, Steel, 60 Tons, Design .1,130. This nonpropelled vessel is equipped with a main hoist block having lifting capacity of 60 long tons at a 73-foot radius and an auxiliary block having a lifting capacity of 15 long tons at a 100-foot radius. It is designed for loading and unloading heavy items beyond the lifting capacity of a vessel's organic cargo handling gear. This crane is used to support salvage operations. k. Crane, Barge, Diesel-Electric, Revolving, Steel, 89 Long Tons, Design 26J,B. This nonpropelled vessel is equipped with crew quarters and messing facilities. It has a main hoist block having a lifting capacity of 89 long tons at an 80-foot radius and an auxiliary hoist block with a lifting capacity of 15 long tons at a 122-foot, 6-inch radius. It is designed for loading and unloading heavy items beyond the lifting capacity of a vessel's organic cargo handling gear. This crane is used to support salvage operations. 8. Landing Craft Landing craft are designed to transport wheeled and tracked vehicles and general cargo from larger vessels to the beach. They are assigned to boat companies and floating craft general support maintenance units. Capabilities and uses of landing eraft are as follows: a. Landing Craft, Mechanized, Diesel, Steel, 69 Feet, Mark VIII, Navy Design LCM (8). This vessel is assigned to a medium boat company and has a crew of six. When not being used to transport vehicles and cargo, it can transport 200 combat-equipped troops. b. Landing Craft, Utility, Diesel, Steel, 115 Feet, Navy Design LCU 1.1,66 Class. This vessel, with a crew of 11, is assigned to a heavy boat company. It is unique in that it can be sectionalized into three parts and deckloaded on cargo vessels for transport overseas. This craft has a cruising range of 700 nautical miles. It can transport 300 combat-equipped troops for short trips such as ship to shore. In addition, it is used to transport general cargo, wheeled, and tracked vehicles in ship-to-shore and shoreto-ship operations. 9. Amphibians The most effective use of amphibians is in over-the-shore operations. These operations are undertaken to supplement conventional ports, to replace ports, to shorten lines of communication, or to achieve dispersion. In this type operation, vessels are anchored offshore and cargo is discharged to the amphibian which then proceeds to the beach and over the beach to storage points. A typical amphibian is the amphibious lighter (LARC-V), Design 8005. This craft is self-propelled and diesel-operated. It is constructed of aluminum and weighs 5 tons. It has a crew of two and can accommodate twenty passengers in an emergency. The most economical distance that this craft can operate on water is two miles. 10. Miscellaneous Vessels Due to tactical and logistical situations, it sometimes becomes necessary to utilize commercial craft or native craft. These craft can be leased, contracted for, or loaned. The contractural agreement for the use of such vessels will stipulate the maintenance and repair that will be accomplished. Unless otherwise directed, the same scope and frequency of organizational maintenance and inspection that applies to unit assigned vessels will apply to any leased or contracted vessels. When attempting repairs to such vessels, local or indigenous materials and parts will be used if they can be procured by local purchase or requisition. Any alterations or substitute component parts that are used will be noted in the vessel maintenance records. Sedion Ill. TOOLS to be performed. A TOE is provided for each 11. General unit, allowing individual tool kits, special tools, The tools required for marine salvage and and power tools as required. When the mission hull repair will be determined by the type of unit involved and the category of maintenance or task of a unit changes or different types AGO 6244A of floating craft are obtained, the unit TOE also changes or is augmented in personnel and equipment. 12. Power Tools (Portable) The most commonly used power tools in repair to marine craft are the power drill, hammer, and the grinder. These can be powered by electric motors or by air (pneumatic) motors. The pneumatic powered tools are the most frequently used, and operators should be specially trained in the proper use and maintenance of them. 13. Power Tools (Nonportable) The heavier stationary machine tools vary WORKING PRESSURE GAGE with the mission of the vessel or station. A vessel designed to patrol harbors will not be equipped with more than a few lightweight machine tools. A floating repair vessel will have many heavy metalworking and woodworking machines. Some of the most common of these are drill presses, beach and pedestal grinders, power hacksaws, handsaws, circular saws, jointers, surfacers, wood lathes, shapers, and tool grinders. 14. Hand Tools Hand tools are issued to the repairman ac· cording to his particular skill such as machin ist, electrician, or marine hull repairmar Figure 2. Portable oxyacetylene welding set. AGO 5244A These tools are for accomplishing normal preventive maintenance, and can consist of items such as hammers, pliers, screwdrivers, socket sets, hand wrenches, calipers, and micrometers. 15. Oxyacetylene Welding Sets An oxyacetylene welding set consists of a cylinder of acetylene, a cylinder of oxygen, one acetylene regulator and one oxygen regulator, two lengths of hose with fittings, a welding torch with tips, and either a cutting attachment or a separate cutting torch. Accessories include a spark lighter to light the torch, an apparatus wrench to fit the various connections on regulators, cylinders, torches, and torch tip cleaning tool, goggles with filter lenses for eye protection, and gloves for protection of hands. A typical portable welding set is shown in figure 2. 16. Electric Arc Machines A variety of shielded metal arc welding equipment is available for military use. An ENGINE SPEED CONTROL HANDWHEEL EXCITER CONTROL HANDWHEEL (0-50 AMP) EXCITER GENERATOR CONTROL PANEL VOLT·AMPERE ADJUSTER example of the type of an electric arc welding machine authorized and issued to Transportation Corps. Marine Maintenance units is a direct current, 300-ampere, gasoline driven, skid mounted, Hobart Model GR-300-S. This machine has about a 3-kilowatt, 115-volt direct current auxiliary generator. This welding machine can be trailer mounted for greater mobility. This set is illustrated in figure 3. 17. Shielded Inert-Gas Metal Arc (Sigma) Most of the shielded inert-gas metal arc welding that is performed aboard vessels is done semiautomatically. The equipment is designed to operate with either constant-potential or variable-voltage de welding machines. It is similar to the equipment used for inert-gas welding with a tungsten electrode, having the same supply and flow-control equipment for water and for inert gas. Some specialized equipment is· required for the sigma process. This includes a portable drive unit, a control unit, and a torch or electrode holder. The drive Figure 3. Electric arc welding machine, 300 amperes, direct current, gasoline driven. AGO 5244A PORTABLE WIRE DRIVE UNIT POWER LINE SWITCH POWER SUPPLY 110 VOLT ELECTRODE WIRE FLEXIBLE CABLE REMOTE SPEED CONTROL BOX WIRE DRIVE MECHANISM Figure 4. Specialized equipment for semiautomatic arc welding. unit feeds the welding wire to the torch at The control unit contains an electronic gov the rate required for the welding. The torch ernor which automatically regulates the rate of is similar to the one used for the tungsten wire feed and all phases of operation as the process, but serves the additional function of operator triggers the switch on the torch. Thisreceiving and guiding the electrode wire into equipment is shown in figure 4. the proper position for welding operation. The Section IV. READING AND INTERPRETING BLUEPRINTS 18. General Blueprints are used in construction work to give an accurate assembling picture of the object to be built: its size, shape, and exact dimensions. In shipbuilding, many blueprints are made up with a specified part of the vessel laid out on each blueprint. Blueprints are valuable permanent records and should be handled with care. They should be kept out of strong sunlight and away from grease or oil. Marks should not be placed on blueprints without authority. If so authorized, an appropriate SYMBOLS USED ON BLUEPRINTS ONE INCH ADDED CENTER MIDSHIP , ..A/J/J m FOR CUTTING i t CENTER LINE ONE ROW RIVETS -@ LOAD LINE ' FOUR ROWS RIVETS HEEL OF STIFFENER (') FT,ORFEET Ft or :I TO LINE IE ... AE AFT END BACK TO BACK STIFFENER FORWARD END lT IE orFE ANGLES IL [ ___ ----_] LAP SEAM CHANNEL IRONJOGGLE SEAM ~ [ SEAM BACK TO BACK C:::=---=9 CHANNEL IRON ___.., I r----- LIGHTENING HOLE L------..1 If SIDE VIEW PLANE ( 18"&24" ) LIGHTENING HOLE Fa PLATE STARBOARD (STAR) WELD MARK ® M £I PORTSIDE WELD ONE SIDE ® c-c CENTER TO CENTER ~ EEl WELD BOTH SIDES CAST IRON LEFT HAND C. I. L.H. COUNTERSINK CsK. R.H. RIGHT HAND FLANGE ZEE BAR FLG. Z.B. Figure 5. Common blueprint symbols. AGO 6244A PIPE FITTINGS, TYPES OF PLUG CONNECTIONS I F ANGLE, RELIEF SCREWED ENDS REDUCER, CONCENTRIC --[:::::+ BACK PRESSURE FLANGED ENDS ---cl:r- UNION, FLANGED ' + ~ BELL-AND-SPIGOT ENDS GLOBE, RELIEF UNION, SCREWEDWELDED AND BRAZED ENDS --+ft- GLOBE, RELIEF ADJUSTABLE, * OR SPRING LOADED REDUCING ~ SOLDERED ENDS e EXPANSION JOINT, BELLOWS -n- PRESSURE REDUCING OR ELBOWS EXPANSION JOINT, PRESSURE REGULATING, ~ SLIDING INCREASED ACTUATING ~ PRESSURE CLOSES VALVE FITTING SYMBOL VALVES, TYPES OF CONNECTIONS PRESSURE REDUCING OR PRESSURE REGULATING, ELBOW, 90 DEGREES INCREASED ACTUATING -r- ~ SCREWED ENDS --cx::::J- PRESSURE OPENS VALVE ELBOW, 45 DEGREES FLANGED ENDS -IC>IK _X_ '1:/X I 0 L '0 II v v y ~ Figure 9. Basic resistance weld symbols. Figure 8. Basic arc and gas weld symbols. CONTOURWELD ALL FIELD WELD AROUND • FLUSH CONVEX 0 ---/'\ Figure 10. Supplementary weld symbols. FINISH SYMBOL CONTOUR SYMBOL~ ROOT OPENING; DEPTH OF FILLING~v------: GROOVE ANGLE; INCLUDED FOR PLUG AND SLOT WELDS f ANGLE OF COUNTERSINK FOR PLUG WELDS LENGTH OF WELD SIZE; SIZE OR STRENGTH FOR RESISTANCE WELDS - "' ~ ffi i=~ ~PITCH(CENTER-TO-CENTER SPACING) OF WELDS ;:;; o;:;; - ARROW CONNECTING REFERENCE LINE TO ARROW SIDE OF JOINT TAIL REFERENCE LINE TO GROOVED MEMBER OR BOTH BASIC WELD SYMBOL FIELD WELD SYMBOL OR DETAIL REFERENCE ·WELD ALL AROUND SYMBOL NUMBER OF SPOT OR PROJECTION WELDS Figure 11. Standard loca.tion of elements on a welding symbol. AGO 6244A APPLICATION DESIRED WELD SECTION OR END ARROW-SIDE FILLET WELD Vl 0 ...J w 3o w > OTHER-SIDE FILLET WELD 0 0 0: C) ...J w > w co BOTH-SlOES FILLET WELD, 0 ONE JOINT z < w· > 0 0 0: C) BOTH-SIDES FILLET WELD, w TWO JOINTS 0: < ::::> 0 Vl t-' w ARROW-S IDE SQUARE GROOVE WELD ...J ...J u::: 0: 0 II.. BOTH-SIDES SQUARE GROOVE WELDVl ...J 0 aJ :::e > "' ARROW-SIDE BEVEL GROOVE WELD BOTH-SIDES BEVEL GROOVE WELD ARROW-SIDE ¥-GROOVE WELD BOTH-SIDES ¥-GROOVE WELD ARROW-SIDE J -GROOVE WELD BOTH-SIDES J -GROOVE WELD ARROW-SIDE U-GROOVE WELD BOTH-SIDES U-GROOVE WELD Figure 12. Application of welding symbols. AGO 6244A CHAPTER 2 HULL STRUCTURES Section I. TYPES OF HULLS 25. ·aasic Hull Forms The three basic, conventional hull fonns are the flat, V, and round bottom (·fig. 13). Each of these fonns has undergone considerable advancement toward producing an ideal hull and many variations exist in each fonn. 26. Flat BoHom Hulls Because of its construction and simplicity, the flat bottom hull (fig. 14) is the most common of the three basic fonns. The main advantages of a properly designed flat bottom craft are speed and stability. Figure 14 shows four variations of typical flat bottom hulls. a. The hull detailed in figure 14 having straight sides with no flare has considerable initial stability; however, it has very little reserve buoyancy with no capability of gaining SHEER (EDGE OF DECK) \ buoyancy. Once a hull of this type has heeled over, it must float its own weight to gain original displacement, and in doing this it sinks lower into the water. This lack of reserve buoyancy is exemplified by a sand barge. b. The hull detailed in figure 14 having i i i 1 I I FLAT VEE ROUND BOTTOM BOTTOM BOTTOM Figure 13. Basic huU forms. SHEER (EDGE OF DECK) ·c_~..........,___ STRAIGHT SIDE STRAIGHT SIDE CONCAVE SIDE CONVEX SIDE NO FLARE WITH FLARE WITH FLARE WITH FLARE Figure 14. Flat bottom hulls. AGO 5244A straight sides with flare is more stable than one without flares. As this hull heels over, it gains displacement on the immersed side, which produces a tendency to return the hull to its normal position. c. The concave and convex hulls with flares detailed in figure 14 are stable craft with reserve buoyancy. Both are drier craft than the craft with straight sides described in a and b above. Of the two, the concave side with flare is the drier craft. d. A longer craft will have greater speed SHEER (EDGE OF DECK) KEEL because of less sweep of the bottom, but greater horsepower is necessary to reach high speed. The absolute flat surface of the bottom will cause pounding, expecially under a strong head sea. A bottom craft with ample flare, fine waterlines, and a full deck will be calm in almost any weather. The bottom of the forward section of the craft should be relatively narrow. This narrowness will lessen the tendency to pound when driven against a head sea at high speeds. SHEER (EDGE OF DECK) '"~-----~- -,__ -,_,_~_;":..::IN!!!t..E-tf- STRAIGHT ABOVE CONCAVE ABOVE CONCAVE ABOVE CHINE STRAIGHT ABOVE AND BELOW CHINE AND BELOW CHINE STRAIGHT BELOW AND BELOW CHINE WITH SIDE FLARE WITH SIDE FLARE AMPLE SIDE FLARE NO FLARE Figure 15. V bottom hulls. SHEER (EDGE OF DECK) SHEER (EDGE OF DECK) LWL "C~-~._ KEEL HARD BILGE SLACK BILGE CONCAVE WITH FLAM STRAIGHT SIDE CONVEX -NO FLARE AND FLARE -DEADRISE Figure 16. Round bottom hulls. 22 AGO 6244A 27. V Bottom Hulls The principle characteristics of V bottom hulls are shown in figure 15. a. V bottom hulls have a chine or angular corner where the sides meet the bottom and form a V. This V extends from the bow to the stern and varies in degress of acuteness. The chine extends through the middle of the bilge for the entire length of the V bottom. The vertical fore-and-aft curvature of the chine depends entirely upon the speed expected of the vessel. Fast V bottom vessels will have practically no curve at all and, in some instances, will have reserve curve. Slow V bottom vessels will have a generous curve and a much sharper V section at the stern end of the hull. The V section tends to strength the hull; however, seams on a V bottom tend to open as pressure is applied. Within reason, the faster a V bottom vessel is driven, the steadier it becomes. b. The sharp sections below the chine shown in figure 15 make the V bottom an easy vessel in a seaway. It will not pound, and spray will be thrown aside. The topsides, above the chine, will also throw the flying spray away from the craft. The advantage of straightness of all the sections makes construction and repair much easier. c. Concave V sections above and below the chine are the most generally accepted for faster craft. Construction and repair are more difficult, but the extremely stable, dry, and nonpounding form makes it a very popular design. d. Straight lines below the chine, with the concave topsides, as detailed in figure 15, simplify the construction of the craft and make it very stable; however, there is some loss of speed with this type hull. e. V bottom forms with nearly vertical sides, as detailed in figure 15, are uncomfortably wet, dangerous, and poor seagoing vessels. There is no reserve buoyancy and, in a hard sea, a vessel of this design will pound. Although con struction and maintenance are greatly reduced in this straightline design, it is an undesirable hull form. 28. Round Bottom Hulls A simple profile and plan of some common examples of round bottom hulls are shown in figure 16. The performance of any craft depends upon the designer and the builder. The hull repairman must maintain the original lines in replacement of any section of the hull. One big advantage of the round bottom craft is the absence of the chine; thus, round bilge crafts are much simpler for the repairman. A round bilge craft is stronger for a given frame and planking size than either of the two forms described in paragraphs 26 and 27. Pressure on a round bilge is similar to pressure on the outside of a barrel, forcing the planks together tightly and closing the seams. A round bilge craft can be made very tight by calking. Steam bent frames, properly set to the keel member and fitted at the deck edge, form a strong type of hull. a. The hard bilge, straight side hull detailed in figure 16 is likely to be a violent roller, wet, and uncomfortable in anything but calm water. The flatness of the bottom and the quick turn of the bilge, combined with the straight sides, are a poor combinatim.~, --This form will have considerable initial stability, but it is lacking in reserve buoyancy. It will also pound and bury the bow in the seas and sling water back over the decks. b. The slack bilge, convex, no flare hull detailed in figure 16 lacks initial stability. The slack bilges allow no bearing, and the vessel is quick and sensitive with the shifting of minor weights or strong seas. c. The concave hull detailed in figure 16 is not ordinarily fast. For a modestly powered craft, however, such a form is very desirable. The flare on the topsides and fine waterlines forward ease it down in a rough sea. There is no pounding or sudden taking up, and the firmness in turn of the bilge gives stability. Section II. STRENGTH REQUIREMENTS 29. General in the structural members and the stresses,. The strength of the vessel hull structure structural and local, which the vessel must redepends upon the strength of the material used sist. The replacement or repair of structures contributing to hull strength should follow detail specifications and finish plans for the specific vessel. 30. Types of Materials Commonly Used The types of materi,als commonly used for the construction of hulls are wood, ferrous and nonferrous metals, and plastic. In each case, the strength and characteristics of each material should be considered with repairing hulls. a. Wood Characteristics and Strength. The various tyeps of wood, their uses, characteristics, and strength as used in the construction of vessels, are listed in table I. Table I. Common Woods Type Uses Ash____________ Oars, craft thwarts, gratings, interior craft fittings. Balsa_________ Rafts, life preservers, loud speak _ ers, sound-proofing, air-conditioning devices. Beech.__________ Wood dowels, capping, craft trim _ Birch__________ Wood dowels, capping, craft trim _ Butternut______ Watercraft ---------------------Cypress________ Small craft planking ------------- Douglas Fir_____ Deck planking on large vessels, shores, strongbacks, plugs, filling pieces and bulkheads of small craft. Elm____________ Watercraft ---------------------- Lignum Vitae___ Block sheaves and pulleys, waterexposed shaft bearings of· large vessels; Live Oak________ Vessel construction Mahogany______ Watercraft, decks ________________ Maple___________ Vessel construction, crossties _____ Norway Pine____ Dimension timber, masts, spars, piling. Red Oak_________ Crossties when preserved _________ Characteristics and strength Strong, heavy, hard, tough, elastic, close straight grain;, shrinks very little, takes excellent finish, lasts welL Lightest of all woods, very soft, strong for its weight, good heat insulating qualities, odorless. Similar: to birch but not so durable when exposed to weather, shrinks and checks considerably, close grain, light or dark red color. Hard, durable, fine grain, even texture, heavy, stiff, strong, tough, takes high polish, works easily, fonns excellent base for white enamel finish, but not durable when exposed; heartwood is light to dark reddish brown in color. Easy to work, coarse grained, fairly strong. Many characteristics similar to white cedar; water resistant qualities make it excellent for use as craft planking. Excellent structural lumber, strong, easy to work, clear straight grained, soft, but brittle. Slippery, heavy, hard, tough, durable, difficult to split, not resistant to decay. Dark greenish brown, unusually hard, close grained, very heavy, resinous, difficult to split and work, has soapy feeling. Very heavy, hard, tough, strong, durable difficult to work, light brown or yellow, sap wood nearly white. Brown to red color, one of most useful of cabinet woods, hard, durable, does not split badly, open grained, takes beautiful finish when grain is filled but checks, swells, shrinks, warps slightly. Fine grained, grain often curly, heavy, tough, hard, strong, rather easy to work, but not durable; heartwood is light brown; sap wood is nearly white. Light, fairly hard, strong. Tends to warp, coarse grain, does not last well when exposed to weather, porous, easily impregnated with preservative, heavy, tough, strong. Spruce__________ Resonance wood, oars, piles, masts, Light, soft, low strength, fair durability, close<>grain, spars. yellowish, sap wood indistinct. 24 AGO 624U. Type Uses Characteristics and strength Table I. Common Woods-Continued Teak___________ Deck planking, shaft logs for small Light brown color, strong, easily worked, durable, resist crafts. ant to damage by moisture. White Cedar____ Craft planking ------------------ Soft, light weight, close grained, exceptionally durable when exposed to water, not strong enough for con struction, brittle, low shrinkage, fragrant, generally knotty. White Oak______ Craft and vessel stems, sternposts, Heavy, hard, strong, medium coarse grain, tough, dense, knees, sheer strakes, capping, most durable of hardwoods, elastic, rather easy to transoms, shaft logs, crossties. work but shrinks and likely to check; light brownish grey in color with reddish tinge; medullary rays are large, outstanding, and present beautiful figures when quarter sawed; receives high polish. Yellow Pine____ Keelsons, r1smgs, filling pieces, Hard, strong, grain varies, heavy, tough, reddish yellow clamps, floors, bulkheads of small to reddish brown in color, resinous, medullary rays craft, shores, wedges, plugs, well marked. strongbacks. b. Plastic Characteristics and Strength. eral classes: ferrous and nonferrous. Ferrous Plastic requires mimmJim maintenance, is metals are composed primarily of iron. Nontough, and can be molded into any desirable ferrous metals are composed primarily of eleshape. Next to the steel plate, plastic is the ments other than iron, but could contain a strongest material put in the vessel hull today. small amount of iron as an alloying element Plastics can be scratched, punctured, and or as an impurity. gouged. For details on the repair of these a. Ferrom Metals. Ferrous metals include all types of damage, refer to chapter 6. forms of iron. Steel, a product of iron, is widely 31. Metals-General used in construction. For the properties and Metals and alloys are divided into two gen-uses .of these metals, refer to table II. Table II. Ferrous Metals Types Uses and properties Boiler and Firebox Steels -'--------These steels can be formed cold and are used in such constructions as boilers, fireboxes, and flanges. Structural Steels -----------------These steels are widely used in the construction of vessels, and often this class includes the boiler steels. Spring Steels --------------------This group includes some plain carbon steels and several alloy steels. These steels are used to make all kinds of springs. Electrical Steels -----------------These are usually very low carbon steels that contain 3 to 4 percent silicon; which ··makes these steels suitable for use in manufacturing electrical machinery. Pipe and Welding Steels __________ These are soft steels that are used to make welded pipe. Plain Carbon Steels _______________ These vary in carbon content from 0.05 percent to as much as 1.7 percent. These steels are known (in order of the amount of carbon present) as mild··steel, low carbon steel, medium carbon steel, high carbon steel, and very high carbon steel. Nickel Steels ---------------------These steels contain 3.5 to 5 percent nickel. The nickel is used to increase strength and toughness. Nickel steels containing more than 5 percent nickel have increased resistance to corrosion and scale. Chromium Steels _________________ These steels have chromium added in order to improve their hardening ability, wear resistance, and strength. These are so highly resistant to wear that they are used for the races and balls in antifriction bearings. Chromium steels cpntaining even more chromium are highly resistant to corrosion and scale. AGO 5244A Table II. Ferrous Metals-Continued Types Uses nnd properties Chromium-Nickel Steels -----------Chromium-nickel steels are used for a variety of purposes where toughness, ductility, strength, and surface hardness are required to meet severe demands of service. Examples of such uses are drive shafts, connection rods, axles, and gears. Chromium-Vanadium Steels -------These steels are strong, resistant to fatigue, and resistant to creep. These steels are used for axles, shafts, driving parts, gears, springs, high temperature valves and valve springs, and other heavy duty services. Molybdenum Steels _______________ These steels are added primarily to increase the effects of the other alloying. elements. In general, the addition of molybdenum tends to increase (1) ductility and toughness, (2) machinability while increasing hardness, and (3) creep resistance. Manganese Steels -----------------Small amounts of manganese tend to produce strong, free machining steels. Larger amounts produce a somewhat brittle steel, while still larger amounts (11 to 14 percent) produce a steel that is tough and, after proper heat treatment, very resistant to wear. Silicon Steels ---------------------These are used for many electrical applications. The addition of silicon tends to improve the electrical qualities of the steel. Silicon-Manganese Steels _________ These are used in applications where high elasticity is desirable and where high shock resistance is not too important. b. Nonferrous Metals. Although ferrous metals are required in the construction and metals are used in greater quantities than the maintenance of most vessels. For information nonferrous metals aboard a vessel, the nonpertaining to the uses and properties of these ferrous metals are of great importance. These metals, refer to table III. Table III. Nonferrous Metals Types Uses and properties Copper -----------------Copper is one of the most important nonferrous metals used in the construction of a vessel. It is used in the form of sheets, tubing, wires, and in copper alloys such as brass and bronze. It is used to give a protective coating to other metals and to fabricate many special parts. The properties of copper make it extremely useful for many applications. It is easy to work, being ductile, malleable, tough, strong, resistant to wear, and machinable. Copper is highly resistant to salt water corrosion and is an excellent conductor of both heat and electricity. Copper seams are usually joined by riveting, brazing, or soldering. Zinc -------------------Zinc is used as a protective coating (galvanizing) on steel and iron. Zinc is also used on soldering fluxes and as an alloying element in some brass and bronze. Highpurity zinc, in the form of sheets, rods, or special shapes, is used to protect hulls, hull fittings, and many types of machinery from the effects of galvanic action. Lead -------------------Lead weighs approximately 700 pounds per cubic foot and is probably the heaviest metal used on a vessel. It is soft and malleable and is commonly supplied in sheet form, rolled on a rod. ·Because of its softness, lead is often used as a backing material for punching and hammering operations. Sheet lead is used to line sinks and to protect bench tops which are exposed to acids. Lead is also used as a radiation shield. Lead alloyed with other metals is utilized in solders, bearings, and other item supporting vessel operation. Tin --------------------Tin is seldom used on a vessel in its pure state, but it has many important uses as an alloying element. 'fin and lead are used together to make soft solders; tin and copper are used together to make bronze. Tin and tin base alloys have, in general, high resistance to corrosion. 26 AGO 5244A Types Brass Bronze ----------------- Copper-Nickel Alloys (Cupro-Nickel). Nickel-Copper Alloys ___ _ Inconel ----------------- Aluminum and Aluminum Alloys. Stellite ----------------- Bearing Metals _________ Table III. Nonferrous Metals-Continued Uses and properties True brass is an alloy of copper and zinc. Additional elements (aluminum, lead, tin, iron, manganese, or phosphorous) can be added to give the alloy specific properties. Rolled naval brass (also known as Tobin bronze) is about 60 percent copper, 39 percent zinc, and 0.75 percent tin. This type of brass is highly resistant to corrosion. Brass sheets and strips are available in grades known as soft, ~ hard, %. hard, full hard, and spring. Hardness is imparted to the brass by the process of cold rolling. All grades of brass can be made softer by annealing the metal at a temperature of 550• to 600° F. (288° to 316° C.). A bronze made of 84 percent copper and 16 percent tin was the best metal available for uses such as tools, and weapons before techniques were developed for making steel. Many complex bronze alloys containing additional elements such as zinc, lead, iron, aluminum, silicon, and phosphorous are now available. The name bronze is now applied to any copper base alloy that looks like bronze; in many cases, there is no longer a real distinction to be made between bronze and brass. A number of copper-nickel alloys are used on most vessels especially in heat exchangers using salt water. Alloys containing 70 percent copper and 30 percent nickel or 80 percent copper and 20 percent nickel are uesd for salt water piping systems becaue of their high resistance to corrosion. Copper-nickel alloys have the general working characteristic!'! of copper but must be worked cold. Brazing or manual shielded metal arc welding can be used to joint copper-nickel alloys. Monel and K-Monel are alloys in which nickel is the predominating element. Monel contains from 64 to 68 percent nickel, about 30 percent copper, and small amounts of iron, manganese, and cobalt. Monel is a highly ductil~ alloy and is harder and stronger than either nickel or copper. It has many of the properties of stainless steel, which it resembles in appearance. The high resistance to corrosion of this alloy makes it generally superior to steel in any system or service where corrosion resistance if of primary importance. On vessels, Monel is used for pump rods, turbine blades, steam valves, control fittings, nuts, bolts, screws, and other parts. K-Monel is similar to Monel but has greater tensile strength and greater hardness. K-Monel is used for such varied items as propeller shafts and small ball bearings used in certain instruments. Inconel is a high nickel alloy often used in engine exhaust systems and for other parts where heat resistance is important. This alloy contains 78.5 percent nickel, 14 percent chromium, 6.5 percent iron, and 1 percent of other elements. Inconel is highly resistant to creep. Aluminum and aluminum alloys are widely used because they are light in weight, easily worked, and strong in relation to their weight. There are many different types of aluminum alloys, and a special numbering system has been adopted for them. Cobalt is the primary element in the alloy known as Stellite. This alloy, which also contains chromium, nickel, and either tungsten or molybdenum, is extremely strong even at red heat temperatures. It is also highly resistant to corrosion and to wear. In most vessels, Stellite is used for the seating surfaces of high pressure, high temperature valves. A number of nonferrous alloys are used as bearing metals. In general, these alloys are tin base, lead base, copper base, or aluminum base. The term Babbitt metal is often given to lead base and tin base alloys used for bearing surfaces. The tin base Babbitts are used in preference to lead base Babbitts where high bearing pressures and temperatures must be sustained. 32. Maintaining Material Strengths affect the designed strength and safety of the vessel. Face plates, reinforcing angles, and free It is undesirable and dangerous to cut holes in free flanges of bulkhead stiffeners or in the flanges of stiffeners should not be drilled or lower flanges of deck beams.. These holes will punched for attachment of gratings, platforms, AGO 6244A foundations, or fittings. Where such attachments are necessary, the holes should be located in the web of the stiffener near the neutral axis. Welding to the standing flange of the aluminum deck house side stiffeners, beams, or griders is not recommended within the midthird length of the span. Any necessary con nections to members in this area should be to the web only and at a minimum distance of 1 inch from the flange. When installing piping systems and electric leads under plated decks, such leads should be run through existing holes in the webs of the deck beams when possible. If it is necessary to cut new holes in the webs of the deck beams to accommodate such leads or piping, the size and spacing of holes should not exceed that given in the detail specifications for the construction of the vessel. No holes ·should be cut in the lower flange of any deck beam, and no more than one horizontal row should be cut in the web of any beam. None of the holes in the deck beams should be located any closer than 3 feet to the stanchion or pillar attachments. · a. Cutting Holes. Holes or openings for any purpose, except those shown by the plans or specifications, should not be cut in any water tight bulkhead, deck, or shell plating except where the local repair or overhaul activity finds such holes necessary. In the case of a private repair or overhaul activity, this determination should be made by an inspector. In all such cases where the necessity for cutting a hole in any of the aforesaid hull structure is indicated, careful consideration should be given to other possible means of accomplishing the desired results. b. Notclws (Geometrical Discontinuities). In accomplishing repairs and alterations, care should be taken to avoid introducing notches, or geometrical discontinuities, in the vessel struc ture, as such points of stress concentration form the starting point of fractures. Serious notches are often caused by striking arcs on plating adjacent to a weld or by leaving rough, burned edges on structure. Rounded cornel"S should be provided when making cuts in strength members. Corners of doublers, insert plates, clips, and pads must be rounded to avoid notch effect. Di~continuities, such as slag inclusions, incomplete fusions, or undercut in a weld, also forms the starting point of fractures, and careful workmanship and inspection are necessary to prevent the introduction of such notches into the structure. c. Watertightness. Prior to and during dehumidification of a vessel, it is necessary that au· free water be removed, water leaks stopped, and weather openings sealed, because all water reaching the inside of the vessel increases the dehumidification load. It is necessary to take the following measures before dehumidification is begun: ( 1) Blank all sea connections. (2) Dry all bilges and keep them dry. (3) Stop all underwater leaks. Tighten shaft on packing glands and stuffing boxes of all ,sea valves. Shafts will not be jacked. ( 4) Drain and dry thoroughly all steam and water piping, all machinery, boilers, and condensers. Check system to ascertain if all pockets which can collect water, such as pump casings and valve bodies, are provided with drain connections. Where drains are not so provided, it will be necessary to disconnect the pipe fitting to permit draining. All drains should be opened, including those on pumps and fittings. The system should then be blown out with compressed air to clear the lines and machinery units of all possible entrapped water. As each drain connection ceases to show flowing water, it should be temporarily closed to allow greater pressure for the remainder of the line. (5) Close all exhaust pipes, ventilation openings, safety valve exhaust pipes, tank vents, drain pipes, and voice tubes to eliminate outside atmosphere. Vents and overflow lines for fuel, diesel, and JP-5 oil tanks which are empty but have not been cleaned should remain open. Welded-on metal covers should be used for sealing smoke pipes or other large openings. (6) Inspect all air ports, hatches, and doors. Insure that gaskets and knife edges are free from grease, dirt, or paint and are in good condition. Adjust dogs, if required, and insure, by a chalk test, proper bearing of knife edges. Where more than one access opening is provided, restrict normal access to only one opening and insure that it is conspicuously marked and dogged tight, except when actually in use. Those doors and hatches which are not required for normal access should be marked SEALEDDO NOT OPEN. Doors and hatches which are to remain closed should be secured and sealed by application of cement, Military Specification MILA-5092, to the gasket and knife edge. To insure proper sealing, the door should be closed and dogged down tightly while the materials are still tacky. Doors that are warped or constructed of light sheet metal with insufficient dogs for proper closure should be sealed by filling all cracks, crevices, and voids with calking compound, Military Specification MIL-C15705 or MIL-C-18969, or other approved materials. All dogs should be wired around each door secured by padlocks or other means to prevent opening. Treat similarly all other possible sources of air leakage such as electric cable stuffiing tubes and voice tube covers. (7) Air test all zones for leakage, using one of the vessel's fans of not more than 2000-cfm capacity, or a fan installed and sealed in a suitable opening in the boundary, in order to force air steadily out of the zone through the leaks. Measure the quality of air flowing and the resulting pressure difference between the zone and the weather. Assume that all the leaks are equivalent to a thin plate orifice which would produce the same pressure with the same airflow. If the area of the orifice computed in this manner does not exceed 1 square foot per million cubic feet of zone volume, the zone is sufficiently tight. If the test reveals the computed area of the orifice to be larger, continue to search for and eliminate leaks until a satisfactory test is obtained. Fine powder or smoke can be utilized in locating such leaks. One simple method successfully to locate leaks consists of an axial flow fan or blower, mounted on a plywood disk, which is lined with a rubber gasket cemented on the underside and placed over the opening of an open manhole or hatch. (8) The above procedure eliminates the excessive entry of water vapor by breathing. The entrance of water from rain, which enters through cracks, seams, and nontight stuffing tubes, or from the sea through seams and leaky rivets must be eliminated. The preferable method of stopping underwater seam or rivet leaks in steel vessels is by chalking, welding, or gunning with waterstop compound such as pine tar and shellac. On wooden hulls, calk with oakum or cotton. For underwater leaks in steel hull vessels, use hydraulic cement for iron or steel, Military Specification MIL-C-1219. When applying the compound, use pressure to hold it in place until dry. For wooden hull vessels, use calking compound, Federal Specification JAN-C-168. For leaky oil seams, use sealing cement, Navy Department Specification 52C21. d. Shoring After Flooding. The main divisional bulkheads are designed, built, and tested to withstand the maximum water pressure likey to be placed upon them under probable flooding conditions. In the event of flooding and damage to any of the main divisional bulkheads, it can be necessary to reinforce the bulkheads temporarily by shoring. Sedion Ill. HULL COMPONENTS vessel. It runs along the centerline at the bot 33. Keels-General The keel is often called the backbone of the tom of the vessel and provides a s,trong, deep, continuous girder from stem to sternpost. The keel ties to the transverse bottom members and, with them, distributes the vessel load evenly over a large area. The function of a projecting keel is to prevent the vessel from making leeway and add to longitudinal strength. In vessels having flat keels, longitudinal strength is provided by the center keelson of a single bottomed vessel and the center girder of a double bottomed vessel. The drawbacks of the projecting keels, as compared with the flat keel, are increased vulnerability and greater draught. The projecting keel has the advantage of enabling a vessel to resist the tendency of driving to leeward and partially reducing the rolling movements of the vessel. The projecting keel has different shapes; it can be a bar keel or a dock keel. The flat keel can be either the ordinary flat keel or the box keel. Another type of keel is the hullfir. keel used on ferry boats. Note. Most Army vessels in current use have a flat keel. a. Bar Keel. The bar keel (fig. 17) is used on tugs and trawlers. It distributes stresses of water pressure and docking pressure, which are transmitted through the floors and keelsons. It is an important longitudinal strengthening member. The stiffness of the bar keel gives the bottom plating protection should the vessel be grounded on a hard or rough bottom. The bar keel also reduces rolling. The disadvantage /___/ J:t'igure 17. Bar keel. Figure 18. Dock keel with and without rivets. KEEL BRACKET (WITHOUT FLANGE) RIDER PLATE KEEL BRACKET (WITH FLANGE) RIDER PLATE I-BEAM KEEL I-BEAM KEEL (RIVETED) (WELDED) Figure 19. Flat-plate keel (1-beam). is that it increases the draught of the vessel without increasing its displacement, thus reducing the payload. b. Dock Keel. The function of the dock keel is similar to that of the bar keel described in a above. The dock keel is a bar keel fitted horizontally and is not so thick as an ordinary AGO 6244A FLOOR TIMBER MIDDLE-LINE KEELSON BOTTOM PLATE Figure 20. Flat keel for flat bottom vessels. OIL PIPES RIDER PLATE 0 0 FLAT-KEEL BOX-KEEL BOX-GIRDER KEEL Figure 21. Box and box-girder keel. HULLFIN-KEEL Figure 22. Typical hullfin keel. bar keel. The minimum thickness of the dock keel is twice that of the keel plate. Figure 18 shows the dock keel assembled with and without rivets. AGO 5244A Figure 23. Typical wood keel. c. Flat Keel. To overcome the disadvantage of the bar keel, the flat or flat-plate keel was developed (figs. 19 and 20). It is the most commonly used keel in cargo vessels. The types of brackets shown in tigure 19 are also used for the flat keel shown in figure 20. The frames or floors are attached to the bracket without flanges. The bracket with the flange is not used to secure framing to the keel. Its purpose is to add strength to the keel and to keep the vertical keel in p1ace. Because this keel is susceptible to chafing along the sea bottom, it is made of stronger material than its adjacent plating. d. Box Keel. The box keel (fig. 21) consists of two vertical keels spaced about 2 feet apart, resting on a flat keel and topped by a rider plate. The box keel, sometimes used on riveted vessels, was developed for tankers. Its pipe alley in the center is large enough to permit a man to walk in and repair the pipelines. The box keel adds to the longitudinal strengthening of the vessel; its chief function is to accommodate the various pipings and cables, so that they can be regularly inspected. The major disadvantage is that a considerable portion has been set apart for holding oil and water; The ends of the box keel occupy a large part of this construction at the points where the box keel changes into the center girder. e. Hullfin Keel. The hullfin keel (fi.g. 22) houses the propeller shaft which has propellers at both ends. The hullfin keel was developed specifically for commercial-type ferry boats. f. Wood Keel. The oldest keel currently in use is the wood keel (fig. 23). This keel, commonly used in small craft, is the main longitudinal SIDE KEELSON _j L MIDDLE-LINE KEELSON + Figure 24. Two side keelsons. strength member and is used as a guide line in the construction of tltese craft. The frames are directly attached to the keel and the garboard strake and other strakes are secured from the keep· upward. The hull structure of craft with wood keels are secured in place with bolts or screws. The advantage of a wood keel and wood construction is that it has a tendency to give when under pounding. When the wood • vessel is involved in a haul out procedure, extreme care must be taken to irisure that the keel is not damaged. A damaged wood keel will reduce the longitudinal strength of the vessel, possibly enough to make the vessel unseaworthy. 34. Keelsons-General · Keelsons are used only in . vessels having single bottoms. They distribute the forces acting upon the vessel over a greater length, strengthen the flat of bottoms, and prevent the floors from bending or tilting. The continuous keelsons are regarded a.S longitudinal scantlings. The transverse strength is, to a small extent, increased by the keelsons. Middle-line keelsons are at the middle line of the vessel; side keelsons are on either side of the former keelson. Both types should be made to continue as far fore and aft as possible. For vessels having a breadth not exceeding 30 feet, one keelson will .suffice. Vessels having a breadth of from 30 to 54 feet have two side keelsons on either side (fig. 24). See figure 24. Vessels having a. breadth larger than 54 feet have th11ee side · keelsons. The middle-line keelson and the side keelsons are provided with lightening holes. a,. Composed Keelson. A variation of the bar keel (para 33a) is occasionally found in the MIDDLE-LINE KEELSON COMPOSED BAR-KEEL ---...:1 Figure 25. Composed keelson (riveted). SHELL PLATING COMPOSED r----BAR-KEEL Figure 26. Composed keelson (welded). shape of the composed keelson (figs. 25 and 26), whose breadth and depth are equal to those prescribed for the bar keel. The centerline keelson extends down to allow sufficient space for riveting or welding. If it should be desirable to use such a composed or three-plate keelson, the welded construction of figure 26 is recommended. b. Middle-line Keelson. The middle-line keel son can be either continuous or intercostal as described below: (1) Continuous and standing upon the floors. This type keelson (fig. 27) is AGO 62UA KEELSON. Figure 27. Continuous middle-line keelson standing upon the.floors. I I ~ FLOOR Figure 28. Continnou.~ middle-line keelson with waterway. composed of two continuous bulb angles or channels; the floors are also continuous. It is used in vessels where the bulb angles form a gutter to drain off excess water (fig. 28). (2) Continuous with intercostal floors. This keelson (fig. 29) is used in large vessels. The foundation plate, with underlying lug-piece, serves to transmit the stresses of one half the floor to the other half. (3) Intercostal with continuous floors. This keelson (fig. 30) is made up of intercostal plating. It is used in small AGO 6244A vessels. By use of electric welding, a much simpler construction is often obtained, resulting in a more satisfactory combination of bar keel and middle-line keelson (fig. 31). c. Side and Bilge Keelsons. These keelsons (ifig. 32) are always intercostal and consist of intercostal plating. To a great extent, this con struction corresponds with that of the middleline intercostal keelson shown in figure 30. For welded constructions, the type shown in figure 33 can be used and can also be the pattern for the middle-line intercostal keelson. Figure 34 shows a bilge keelson found in some vessels. d. Middle-line Keelson Made Continuous through Watertight Bulkheads. The middle-line keelson should be continuous through watertight bulkheads. In order to obtain a watertight structure, a watertight collar angle is fitted around the continuous bulb angle. Figure 35 shows such a construction for the middle-line keelson shown in figure 24. The bulb near the bulkhead is often cut off, resulting in a simpler construction of the collar angle. (See dotted lines A, figure 35.) Care should be taken to insure that at each of the three corners of the collar angle, two additional rivets are inserted just outside the bulb angle flanges. The first rivets (P, fig. 35) serve to draw the two adjoining parts of the collar angles firmly together; the second rivet (Q) makes it possible for the ends (B) to be properly calked. It is more convenient to attach the angles to the bulkhead by welding them all around and cutting off the bulbs. In the case of a continuous middleline keelson shown in figure 28, the welded construction can be obtained as shown in figure 36. An effective weld can be obtained by cutting off part of the bulbs. e. Wood Keelson. The wood keelson is normally made of spruce, Douglas fir, or cypress, and the sections scarfed. This member is located over the floor timbers along the centerline and aids in strengthening the vessel. The keelson, floor fillers, and keel are through-bolted at each frame with two carriage bolts. The stern post is gusseted to the keel and keelson on both sides (fig.37) SIDE FOUNDATION PLATE INTERCOSTAL KEELSONREVERSED FRAME FLOOR r ~ --\ -I - 0 :o-Q. 0 o-o-o-0 _,_ .... -<-------------~o-1 - -~--- 0 0 0 - - FRAME /""' ..,. 0 0 .... __, / 0 2 HOLE LIGHTE~G FR~ - ..... 0 0 ·= .... ---------__j 0 0 '-- TOP VIEW ~ REVERSED FRAMESIDE INTERCOSTAL LIGHTENING HOLE KEELSON FOUNDATION PLATE .JL END VIEW /REVERSED FRAME I "' 17' "ccl7' "ccl7' "eel? ""' V" Jl : :o::o::o::o::o::o::o: :o: :~ oo 00 oo oo 00 00 oo 00 00 00 00 00 00 00 oo oo 00 00 1 00 00 QO 00 00 00 OQ 00 00 oooool ooooooooo ooooooooo oooooooool ooooooooo oooooooool ooooooooo oooooooo.AI ooaooooool oooo SIDE VIEW Figure 29. Continuous middle-line keelson with intercostal floors. 35. Stringers the bottom, and horizontal stringers supply the horizontal strength under the deck. Stringers (fig. 17) are fore-and-aft girders running along the side of a vessel. They are 36. Frames and Deck Beams also the outboard strakes of plating on any deck. There are several sets of fore-and-aft girders Frames and deck beams are two of the most in the framing of a vessel. Longitudinal stringimportant structural members used in the hull ers or keelsons supply the vertical strength in structure. The frames are directly connected to AGO 5244A ..J LUG PIECE? FRAME !-<•----MIDDLE-LINE ] _ INTERCOSTAL KEELSON J., L._"oo' SECJION AT A-A Figure 30. Intercoastal middle-line keelson with continuous floors. MIDDLE-LINE KEELSON II FLAT BAR OR ANGLE FLOOR Figure 31. Combination bar keel and middle-line keelson. the deck beams and keel, giving the vessel its solidness. A typical section of the hull structure, showing the location of the frames, deck beams, and their components, is shown in figure 38. a. Frames-General. The main support for the hull shell-plating against water pressure is the transver&e framing system. Perpendicular to the keel, these frames support the weight AGO 6244A r I ( I o o o o o~~l o 0 0 01"\:" 0 0 J ~0 biO 0 l II I 0 0 :~:0 1\o: II I 0 1101 jl I 110 1 0 II I lb: oo :::: I 10 0 : OCilL 0 0 o o o .1101 o o o ol/ 0 0 ] SOLID BRACKET WATERTIGHT l FLOOR FLOOR FLOOR Figure 32. Intercostal plating. .. 0 0 0 0 0 0 0 0 0 0 0 0 SOLID BRACKET WATERTIGHT FLOOR FLOOR FLOOR Figure 33. Intercostal plating (welded). on deck by transmitting the vertical forces to the floor plates at the bottom of the vessel. The transverse frames vary in shape from the bow ...~ / / Figure 34. Typical bilge keelson. .------------1 I Q B 0 0 0 0 0 0 0 B 0 0 0 0 ~WATERTIGHT CONTINUOUS BULKHEADMl DOLE-LINE KEELSON I I Figure 35. Fitting of watertight collar. to the stern and are usually numbered from fore to aft (fig. 37). For greater strength at certain frame stations, the frames are replaced 36 ,----------------- BULB PARTLY CUT OFF TTER WATERWAY COLLAR PLATE CEMENT Figure 36. Welded watertight collar. by web frames or transverse bulkheads (fig. 38). In the transverse framing system, floor plates are web sections containing lightening holes which strengthen the bottom structure of the ordinary frame. Another type of framing system is the longitudinal framing system which imparts longitudinal strength and rigidity to the vessel. This system is composed of longitudinals, stringers, and girders as shown in figure 38. The longitudinals run parallel to the keel and at right angles to the transverse frames and bulkheads. Side stringers, center and side deck stringers and girders, and the longitudinal frames provide longitudinal strength and rigidity. Besides the ordinary frames, there are special types such as intermediate frames, web frames, deep frames, and open frames. (1) Intermediate frames. Intermediate frames (fig. 39) are used where the shell requires additional strengthening. They are erected between the ordinary frames of the vessel. (2) Web frames. Web frames, also called plate webs or wide spaced frames, are used in the engine and boiler spaces and in vessels built to the longitudinal frame system. Figure 40 shows a web frame system used for both riveted and welded constructions. The welded AGO 1124U. PILOT HOUSE AND BRIDGE TRUNK SIDE BRIDGE DECK DECK BEAM LONGITUDINAL BULKHEAD BOTTOM INNER DIAGONAL PLANKING INNER STRAP FRAME Figure 37. Midships section. construction constitutes a considerable saving of weight. Web frames are often erected after every sixth frame. (3) Deep frames. Deep frames are strongly built in way of the panting arrangement. They are deeper than the amidship frames of the vessel. This construction is frequently adopted because side stiffeners are troublesome and hazardous obstacles. (4) Open frames. Open frames (fig. 41) are used in the area of the higher AGO 6244A decks and long bridgehouses. Different constructions are in use for these built-up frames (fig. 42). When welded, . they are considerably improved and simplified. b. Deck Beams-General. The deck beam has three primary functions: to act as a beam to support vertical deck loads; to act as a tie or strut to keep the sides of the vessel in place; and, to act as a web under the deck plating to prevent plate wrinkling due to twisting action from maneuvering or from sailing at angles SHEER SIDE STRAKE WEB FRAME GUSSET PLATE GAR BOARD BILGE STRAKE Figure 38. Structural members. INTERMEDIATE FRAME Figure 39. Intermediate frames. to a heavy sea. Deck beams run athwartships from side to side and are fastened to the frames by beam brackets. These brackets are fitted to the ends of beams where they connect with the supporting frame. Deck beams are subjected to end-on compressive forces when acting as a strut and to tensional forces when acting as a tie to keep the decks from springing apart when the vessel is in a sagging attitude. A bracketed beam also tends to check the racking and twisting of the hull when the vessel is in a seaway. The usual depth of the beam bracket is 21/2 times the depth of the beam. The function of the beam is to take the deck load and transfer it to the frames. The frames, in this case, act as pillars and carry the load downward, where it is distributed over the bottom of the floors. Water pressure under the bottom of the vessel, transmitted through the floors, frames, and deck beams, supports the load on the deck. The beams support the decks or platforms with their permanent or temporary loads. They also assist in maintaining the relative positions of the opposite sides when the vessel is subjected to longitudinal bending forces or forces due to water pressure upon the immersed surface. AG.O 5244A BUILT-UP FRAME AR~~A SIDE STRINGER SHELL PLATING FRAME B B RIVETED SECTION A-A c:::J FRAME IN HOLDc:::J Figure 42. Built-up frames. H WELDED SECTION B-B as strength members of a vessel's structure andare sometimes called structural bulkheads.Transversed or structural bulkheads are flatplated, vertical partitions which divide the hullinto several compartments or holds and are0 designed to perform several functions. Beingstrong and watertight, structural bulkheadscontrol and confine flooding where the outershell or plating has been penetrated, and they Figure 40. Web frame system (riveted and welded). limit the spread of fire. The strength of structural bulkheads increases the transversestrength of the vessel, transmits the forces ofweight carried in the vessel, and distributes thisweight evenly to the lower portions of the hull. BRIDGE BULKHEAD Structural bulkheads usually have evenlyspaced vertical members built into the flat surface for added strength. These strengtheningmembers are called stiffeners. Bulkheads aregiven names based on their location or function. CONTINOUS FRAME WEB FRAME For example, the bulkhead located in the forepeak of the vessel is called the collision bulkheadFigure 41. Open frames. because in a collision this bulkhead would normally be undamaged and would prevent flooding 37. Bulkheads of additional compartments. Watertight doorsare huilt into some bulkheads for access be In comparison, the bulkhead of a vessel cor tween compartments. Watertight doors are not responds to walls in a building; that is, the permitted in collision bulkheads as they would bulkhead can be constructed transversely which decrease the strength and defeat the major pur is from side to side or longitudinally, running pose of the collision bulkhead. All vessels havefore and aft (fig. 43). However, Longitudinal a quantity of nonstructural or partition bulk bulkheads are usually employed in the construc heads. These bulkheads are so termed because tion of tankers and naval ships but do not apply they do not add structural strength to the ves to cargo vessels. Transverse bulkheads serve sel and are not watertight. The primary pur- AGO 6244A 39 bulkhead, sometimes called the fore-peak bulkSHELL head, is a watertight partition in the foremost STRAKE section of the vessel normally extending from the bottom of the vessel to the weather deck. As its name indicates, this bulkhead is designed to prevent a vessel from going down in case of collision. After these bulkheads are installed, their watertight integrity should be checked. Tests and inspections are discussed in chapter 11. b. Oiltight Bulkheads. An oiltight bulkhead is a partition of plating that is reinforced, where necessary, with stiffening bars and is capable of preventing the flow of oil under pressure from one compartment to another. The riveting, if rivets are used, must be done more closely than in watertight work, and special care must be taken with the calking. c. After-peak Bulkhead. An after-peak bulkhead is the first transverse bulkhead forward of the stern post. This bulkhead forms the forward boundary of the after-peak tank and must be made watertight. Figure 1,.3. Typical transverse bulkhead. d. Centerline Bulkhead. The centerline bulkpose of nonstructural bulkheads is to separate head is a fore-and-aft or longitudinal bulkhead areas. Examples of nonstructural bulkheads erected on the centerline or in the same plane are ones which separate staterooms, storerooms, as the keel. and galleys and are made of wood or metal, as e. Joiner Bulkhead. A joiner bulkhead is a required. Another type of nonstructural bulkwood or light metal bulkhead serving tohead is called the swash or wash bulkhead or bound staterooms, offices, or storerooms. Joinerplate and is most often found in the tanks of a bulkheads do not contribute to the vessel's vessel. Swash bulkheads are normally installed strength. transversely and longitudinally and have numerous perforations. The purpose of swash f. Partial Bulkhead. A partial bulkhead is a bulkheads is to slow the side-to-side movement bulkhead that extends only a portion of the of the liquid in the tanks which affects the staway across a compartment. These are generally erected as strength members of the structure. bility of the vessel as it rolls with the sea. a. Watertight Bulkheads. Watertight bulkg. Recess Bulkhead. A recess bulkhead is a heads are partitions of planking or plating rebulkhead bounding a compartment that is reinforced, where necessary, with stiffening bars cessed from a main compartment. and are capable of preventing the flow of h. Screen Bulkhead. A screen bulkhead is a water under pressure from one compartment light nonwatertight bulkhead fitted between to another. All seams, butts, and connections of the engine and boiler rooms. The bulkhead isplating or planking must be efficiently calked, fitted to keep dust and heat from the engineand the strength of the structure must be suffiroom and is often constructed around the aft cient to withstand pressure. Watertight bulk ends of the boilers.heads have a three-fold function: to divide a vessel into watertight compartments; to ini. Swash Bulkhead. A swash bulkhead, also called a swash plate, is a nonw3Jtertight divicrease the vessel's transverse strength; and to sional bulkhead usually erected longitudinallyprevent the spreading of any fire. The collision AGO 62"A 40 and transversely in all tanks. These bulkheads serve as a baffle to slow the excessive movement of fuel or water in a tank which can affect the stability of the vessel. 38. Planking and Plating a. Planking-General. A wooden craft is usually doubleplanked and has cotton duck laid in marine glue, Military Specification MIL-G413, between the two layers of planking (fig. 37). (1) Inner planking. The inner planking of a craft runs diagonally at approximately a 45-degree angle. This planking is attached by screws to the keel and chine. It is secured to the frames with copper nails. (2) Outer planMng. Outer planking is run longitudinally with the butts staggered on but blocks between the frames (fig. 44). Butt blocks have the same thickness as the outer planking. The outer planking and butt blocks are fastened flush with screws. Fasteners are surfaced with hard surfacing putty, and the fastening holes are not counterbored and plugged. The planking is installed as tightly as possible with no calking seam except the garboard seam. This seam is calked lightly with cotton and filled with sur facing putty. Plank ends are bolted Figure 44. Typical location of butt blocks. AGO 5244A through the butt blocks with three bronze flathead bolts. The inner and outer plankings are fastened together between the frames, from the inside, with wood screws. (3) Main deck planking. The main deck planking is laid in long lengths with butts bolted to butt blocks between beams. It is secured to the deck beams with nails and into the edge of the topside planking and clamp with screws. Removable sections are provided over the engine room for removal and installation of the main engines. (4) Bridge and cockpit planking. The bridge and cockpit planking is secured in place with screws. A weathertight, removable hatch for access to the storage space is provided in the cockpit. b. Plating-General. Plating for the outer skin of a steel constructed vessel, in addition to keeping the water out of the hold, contributes largely to the strength of the vessel. The function of the shell plating is three-fold: to shut out the sea water; to take up stresses resulting from water pressure perpendicular to the shell plating; and to take up bending stresses caused in a seaway. (1) Inner plating. The inner plating of some vessels runs diagonally at approximately a 45-degree angle. This plating is welded or riveted to the keel, chine, and clamp, and fastened to the frames. (2) Outer plating. The outer plating of a vessel is laid in rows, called strakes. The garboard strakes are those nearest the keel on both port and starboard sides. The strakes are lettered A, B, C, and on, up to the top sheer strake under the bulwark. 39. Floors-General A floor is a plate which is placed vertically in the bottom of a vessel, usually on every frame athwartships from bilge to bilge. The inside flanges or webs of the frame bars are riveted to the lower edge of the floors, and the to the top. The costal plates (fig. 27). The continuousreverse frames are riveted floor is used only for small vessels. floors are generally cut in the way of the vertical center keelson to which they are attached (2) Intercostal. In these floors, the midby angle clips on each side. As in the case of dle-line keelson is continuous, and the the longitudinals, they are sometimes continufloor consists of two separate halves ous and sometimes intercostal; but, in any (fig. 45). With the aid of small angles, event, the longitudinals and floors are securely called lug angles or lug pieces, the two clipped together, forming a strong, box girderframe halves are attached to the con like structure. tinuous middle-line keelson. The floor remains straight at the top and is a. Floors-Single Bottomed Vessels. Floors fastened to the frame by means of astrengthen the vessels's bottom and add conflanged knee. In small vessels, the topsiderably to the transverse strength. They are of the floor is provided with a flangein both single and double bottomed vessels. instead of a reversed frame. TheSeagoing vessels have a floor to every frame; width of this flange is the same as thewhereas rivercraft often have one floor to reversed frame, but the thickness of every other frame. As the water pressure on the floor plate is 0.5 mm more. In thethe vessel's bottom increases with draught, the engine room, the boiler room, and thebottom should be made stronger and the floor fore body of the vessel, the floor more solid in proportion to the draught inshould be provided with a reversed crease. The vessel's bottom must be made frame, both frames having the same stronger with an increase of width. Besides thickness. For the fore-and-aft parts the water pressure, the vessel's bottom has to take up stresses caused by the rolling, pitching, of a vessel where shape becomes more and vibration of the engine. The floors in the pointed, the floors must be built engine room and boiler room should be of deeper. Where the vessel breadth strong construction. The floors in single botamounts to half the molded breadth, tomed vessels can be constructed as follows: the depth of the floors is increased by one half. Every frame which need (1) Continuous. The floors cover the en tire vessel and the middle-line keelson not be watertight is provided with a watercourse or limber hole for drain is interrupted and built up of inter _jL LUG PIECE __..:::;'1 r _jL CENTER THROUGH PLATE KEELSON /---FLANGED KNEE 1-----eE!ai L r'FLOOR ·t--FRAME SECTION AT B-B SECTION A-A ~~~~~~~~-2-2-2 0 0 0 0 0 0 0 Oooooo FLOOR Figure 45. Typical intercostal ftoor construction. AGO 5244A WATERCOURSE REVERSED FRAME Figure 46. Location of watercourse in cemented floors. ing off leakage and condensed water. This hole has a diameter equaling that of the bilge pipes and varying between 11;2 and 4 inches. Frequently, additional apertures have been made in the vertical flange of the frame immediately under the floor plate in order to drain off what little water has been left. For economy of weight in large vessels, the floors are often provided with lightening holes having an approximate diameter of 12 to 16 inches. In the fore-and-aft portions of the vessel, a large part of the space between every two successive floors is filled with cement. The limber holes in these floors are situated higher, immediately above the layer of cement (fig. 46). b. Floors-Double Bottomed Vessels. The stiffening, to which all parts of the double bottom have to be subjected in both the engine and boiler spaces, also applies to the floors. In riveted construction, the floor is connected to the flat of the bottom by a frame, to the inner bottom plating by a reversed frame, and to the margin plate and center girder by angle bars. All-riveted construction is seldom used because the welded construction is being generally substituted for it. In the welded construction, the floor is attached directly to the plates by fillet welds or flat bars welded to the center girder and the margin plate. Plate or AGO 62'~ solid floors, bracket floors, and watertight or vessels. (1) Plate floors. Plate floors are connected to the frames, one to each frame in the engine room, under the boiler seatings and watertight bulkheads in the fore part of the vessel and .under part of the thrust block. In other parts, they are attached one to every second or third frame and spaced not more than ten feet apart. In vessels carrying ore, only solid floors are used, one floor attached to every frame. Solid floors are provided with lightening holes, watercourses or limber holes, and air holes. Where no solid floors are required, bracket floors are used. (2) Bracket floors. A bracket floor is composed of a bracket plate in the middle line of the vessel between frame, reversed frame, and center girder, and of a bracket plate between frame, reversed frame, and margin plate. Both brackets are of a thickness equal to that of the solid floor plate. They are flanged and have a width of at least %, the height of the plate keel. (3) Watertight or oiltight floors. Watertight or oiltight floors afford a boundary to the tanks in double bottomed vessels. The plate thickness of these floors should be 0.080 inch, or heavier than ordinary floors. If the height of the center girder is above 36 inches, the floors are provided with vertical stiffening angles having a spacing of 30 inches. With the reversed frame, the frame forms a continuous angle bar which must be continued in way of the overlaps; in the case of plate floors, it can be intercepted at the seams.. For ordinary floors, the reversed frame is a single angle bar, except in the engine room or under the boiler seatings and thrust block where either a double or a single double-riveted angle is used. The second angle extends from the center girder to the longitudinal stiffener outside the engine or thrust block seating. The flanges of the revesed frame are lJ2 inch narrower than those of the frame. When electrical welding is used, the welding seams are made heavier in places where double angles are used in the riveted construction. 40. Walking Flats Walking flats are platforms provided within the engine room to facilitate proper maintenance and periodic inspection of the vessel's engine. 41. Engine Beds Engine beds (fig. 47) are bolted to the engine bed stringers at an angle in line with the propeller shaft. The forward ends of the engine beds are provided ·with an engine anti- KEELSON ENGINE BEDS KEEL ASSEMBLY Figure 47. Typical engine beds. tripping bracket to keep the engines and beds from rocking back and forth when the vessel is at sea. 42. Partitions and Compartments Partitions and compartments compose the inner structure of a vessel. Each partition is a divider which forms the compartments, walkways, and cargo areas. Figure 48 shows a typical arrangement of compartments and partitions in a tanker. a. Partitions-General. Partitions usually include the sides of passageways, the divisions between cabins and passageways, the sides of cabins, and the separators between adjoining cabins. They can be constructed of wood, aluminum, or steel alloys and are commonly known as bulkheads (para 37). b. Compartments-General. A vessel interior is divided into compartments, some of which are forepeak, forward, engine room, dispensary, and cockpit. The forward compartment · and dispensary bulkheads are fastened to headers, beams, and corner posts. The decks are supported by beams and carlings, and the compartment tops are covered with cotton duck set in marine glue. The engine room is formed by the outer planking or plating, bulkheads of the forward compartment and dispensary, and the bridge deck. The cockpit is an open deck surrounded by bulkheads. The ends of the cockpit are formed by the dispensary and transverse gate. The forepea'k is normally a ballast tank formed by the side planking or plating ·and the forepeak deck. 43. Built-in Lockers A built-in locker is attached to the structure of the vessel. These lockers are usually painted a dull white on the inside and the same color as the surroundings on the outside. These lockers are located on and below deck. They are used for the storage of food, equipment, and miscellaneous gear. 44. Seatings The function of engine and boiler seatings is to bear the weight of the machinery and to prevent the machinery from shifting and overturning during the rolling and pitching move- AGO 6244A Figure 48. Typical a1·rangement of compartments and partitions in a tanker. ments of the vessel. Figure 49 shows the location of seatings on a double bottomed vessel. Seatings or machinery foundations are discussed in chapter 10. 45. Seats and Ladders Ladders are used exclusively in places to which only the vessel complement have access, such as cargo holds, tanks, trunks, escape trunks, funnels, masts, and derrick posts. In these cases, with the exception of cargo holds, the use of stairs is all but impossible. Ladders are fastened to the deck through the use of seats (fig. 50) which insure the steadiness of the ladder. a. Accommodation Ladders. These ladders (fig. 51) are provided to enable passengers and crew to board and leave the vessel safely when it is at an anchorage or alongside a pier. Accommodation ladders, up to about 26 feet in length, have an upper and a lower platform, while a ladder of greater length has an additional middle platform. The lengths of the upper and lower portions of the danger accommodation ladder are determined so that the Figure 49. Location of seatings on a double bottomed vessel. AGO 5244A 45 'CURTAIN PLATE Figure 50. Typical ladder seat. middle platform can be used with a fully loaded vessel and the middle and lower platforms with an empty vessel. The upper platform is hinged to the vessel's side with the ladder attached. The ladder is raised and lowered by a tackle. The bottom block or the steel wire is provided with a yoke from which the ladder is suspended. The best position for the ladder is at an angle 45 to 50 degrees to the horizontal when the distance up and the distance forward of the treads are about 15 inches. When not in use, the accommodation ladder is lashed by manila line to the underside of a deck or against the inside of the bulwark. Another means of stowage consists of folding the ladder against the bulwark or railing, mounting it on wood covered supports, and lashing it with manila line. The folded ladder should not project beyond the side of the vessel. The upper platform remains hinged to the side, enabling the ladder to be lowered quickly. b. Hold Ladders. Hold ladders (fig. 52) are installed in vessels in which the bottom of a hold is at a-distance of more than 11.7 feet from the top of the hatch coaming at the side. In case there is more than one deck, the ladders which provide communication between the hold and various decks will be in line with each other, while they· will be continued by means of suitable arrangements in way of the hatchways. In the case of hatchways more than 24.375 feet long, at least one ladder will be provided forward and at least one aft of a hatchway. c. Tank Ladders. In the cargo tanks of tankers, the ladders (fig. 53) are placed with the greatest possible incline. These ladders consist of angle steel poles and rungs of round, angle, or hoop iron. They are provided with round stock steel hand rails, which are fastened to the side pieces by short stanchions. The hand rails will not be made of pipe. Because the angle steel poles are very heavy, they are stayed in one or two places by angle steel, attached to a bulkhead or stringer. Because the oil, in many cases, must be heated, the ladder should be free to expand. The poles are provided with oval holes at the top for the insertion of bolts with split pins. d. Outboard Ladders. Outboard ladders (fig. 54) consi,st of side pieces made of 11/t-inch wrought-iron pipe railings and steps of %-inch wrought-iron pipe. On cargo carriers which are loaded and unloaded in midstream, it is often considered to be troublesome to unship the accommodation ladder for a few days. Therefore, a wooden ladder can be suspended from the railing with the aid of an outrigger as shown in figure 55. Sometimes a rope ladder is used for boarding; however, a wooden ladder is preferred. e. Pilot Ladxlers. Vessels of more than 200 tons gross are required to be provided with a pilot ladder (fig. 56) of sufficient length. Its steps consist of boards, chocks, or double rungs which will not cant when stepped on. The ladder extends from the main deck to the light waterline or, if the ladder has a lengthening piece, the upper portion reaches from the main deck to the load waterline and the lengthening piece from the load to the light waterline. The steps are of ash, beech, oak, or teak. Ash, being the toughest of these materials, is preferred. The guides are made of tarred hemp or manila rope 3 inches in circumference which is seized with spun yarn above and below each step. To prevent canting sideways, sheer battens which are of the same material as the steps. can be provided with the ladder. f. Railing Ladders. Railing ladders (fig. 57) are used in place of bulwark doors to give access to the gangway or to the accommodation ladder. Th~ railing ladder is provided with hooks gripping the bulwark rail, so that it can AGO 5244A FIXED TURNBUCKLE STANCHION ICHAIN ---o-1 LOAD WATERLINE ~--------------------r 1 I 1·----"'- I I LOWER PLATFORM I I LIGHT WATERLINE Figure 51. Typical accommodation ladder. be fitted anywhere to the bulwark or railing. It has a portable stanchion or a short hand rail. It is generally dangerous, particularly in darkness, to pass from the gangway to the ladder; therefore, a portable platform fitted with a railing should be provided. AGO 5244A 46. Ladders Ladders are used to provide access to the various decks outside the cargo holds. They are built on the starboard and port sides. Ladders, leading to poop, bridge, forecastle, or other spaces to which only the crew have access, are generally constructed of steel. Ladders leading to the upper bridge decks and decks used by passengers are constructed of wood. ~ :~----~~~,~~ IL..J--- 1/ " Figure 52. Typical hold ladder. Figure 53. Typical tank ladder. AGO 5244A ------n ,, A==== =A=-=~~= 11 II tl tl I PIPE RAILING (1-1/4 IN.ID) I ' I I _l ___L_ Figure 54. Typical outboard ladder. WOODEN LADDER Figure 55. Typical wooden ladder (outboard). Figure 56. Typical pilot ladder. 47. Decks-General A vessel is provided with one deck or more, not only to make its top. watertight, but also to protect its cargo and accommodate passengers and crew. A deck adds to the longitudinal and partly to the transverse strength of a vessel. The top-most continuous deck of a fullscantling vessel is called MAIN DECK. On a complete superstructure vessel, it is called UPPER DECK. Below these strength decks can be various other decks. The lower decks are not always continuous. They can be interrupted by the engine room and the boiler space, AGO 61~ Figure 57. Typical railing ladder. where the connection between the parts is genof these decks at any given point, which greatly erally effected by side stiffeners. The decks facilitates the marking off of the vessel. In usually run parallel at the middle line of the cargo vessels, this deck spacing influences the vessel. An equal amount of camber of two sucamount of stiffening of the deck below the cessive decks is attended with an equal ·spacing upper deck. A deck must be stiffened if the 50 AGO 6244A height between the decks is more than 8 feet and the deck is loaded with cargo. Decks normally have a transverse camber. The degree of camber is called HEIGHT OF CAMBER, except in the case of beams where ROUNDINGUP is the term used. In the center portion of the vessel, it amount to l/50 of its largest breadth. The longitudinal run of the deck line is also a curve with a rise toward bow and stern. This line is called SHEER LINE. The difference in height between any point in a deck and the lowest point in this deck amidships is termed the SHEER of the former point. In the fore part of a vessel, this sheer is from two to four times that in its after body. The function of both sheer and camber is to increase the strength of a deck and to enable sea water swept on board to flow away through the freeing port's and scuppers. In addition, the sheer improves a vessel's outward appearance and increases its reserve buoyancy. Hence, seagoing vessels are given a heavier sheer than river craft. The deck camber can be constructed in various ways. In marking off the deck line, it is essential first to draw it at the centerline of the vessel and only then at its sides. If this is not done, a sloping deck could be obtained. a. Steelwork of Wood Decks. The partial steel plating required for the longitudinal strengthening afforded by this type of deck extends all along the sides and compri,ses the deck stringer plate, the tie plates, and the diagonals. ( 1) The deck stringer plate provides a firm attachment between the beams and the shell plating and consequently contributes to a vessel's longitudinal strength. (2) The tie plates extend along the deck openings such as the hatches. They prevent the beams from bending longitudinally and thus, to a certain extent, add to the longitudinal strength. (3) Diagonals are sometimes fitted fore and aft; more often, they are only fitted abreast of the masts. They prevent torsion or twisting stresses when the vessel acquires a position obliquely to the wave lines. Strips of plating are further laid underneath winches, masts, and bollards and on watertight bulkheads, besides transversely along the hatches and deck houses. These strips of plating provide a firm attachment to the wood deck, or in the case of bulkheads, to the bracket plates. In small vessels the breadth prescribed for the plate is sometimes small, in which case the gunwale angle bar or the gunwale beam is fitted in such a way that enough space is left for a thorough fastening of the deck planking. In some cases, this can necessitate an increase of the width of the stringer plate. The butts of the stringer plate have to be shifted at least two frame spacings from those of the shear strake. b. Steel Decks. A steel deck is made up of strakes of plating extending fore and aft. The deck stringer plate has its widrth and thickness prescribed by rules, whereas only the thickness of the remaining strakes has been fixed by construction standards. The plates used for decks generally have smooth surfaces, except for small vessels. Decks of small vessels, such as tugs and river craft, are often constructed of checkered or beaded plating. The plates of a strake are combined by means of overlaps, single, double, or treble riveted. Steel deck plates are also connected by butt or overlap welds. Various methods are used for interconnecting the strakes. Regardless of the method all seams must be watertight. If a smooth surfaced deck is required, the plates are sometimes given a downward joggle. For an effective connection, the beams must be recessed or the horizontal beam flange or the joggle burned off locally and beam and deck plating welded together. For obtaining a proper disposition of the deck plating, care is taken to use plates having their maximum width and to give the butts of two successive strakes a shift of at least two frame spacings. No butts should appear near the corners of large openings such as hatchways, as the corners have to be given a rounding with a large radius of curvature and provided with doublers to prevent them from being torn. An edge lap is often in line with the longitudinal side of the hatchway, which presents some difficulties in fitting a doubling plate. AGO 6244A In a riveted construction, the attachment of the deck stringer plate to the shell plating is effected by means of an angle bar. An angle bar is frequently used in a welded construction. On the main deck the deck stringer angle bar is continuous. On the lower decks it is interrupted at the frames where another angle bar is fitted continuously along the inner edges of the frames. c. Wood Decks. Wood decks are laid directly over living quarters and over areas in which there are no other decks unless insulating material is against their undersides. Normally, however, wood decks will be found in the following cases: on top of the wheelhouse, on the navigating bridge, and on the bridge deck. In the construction of vessels where cost is the first requirement, a wood deck is omitted, the underside of the steel deck is insulated. (1) Attachment of deck planks. Deck planks are secured to the steel deck or deck beams by welded bolts or through-bolts. Welded bolrts can be used only where a full plated steel deck is provided under the wood decks. (a) Welded bolts are made in two types, a beveled point and a blunt point. The bottom sides of the planks require less boring for the beveled point bolts. Welded bolts are usually not galvanized. The nuts are made of galvanized iron or brass and are either round or hexagonal. The round nuts have a saw cut for tightening purposes. They are stepped for planks up to 2.340 inches thick and have the same diameter throughout their height for planks greater than 2.340 inches thick. The hexagonal nuts do not have beveled edges and are less expensive than round nuts. Because they must be installed with a socket, the holes in the plank must be made larger than holes for round nuts. A 0.390 inch thick, galvanized iron or brass washer is used under the nuts. For 2-inch decks, bolts 1.287 inches long are used; for 2%-inch decks, 1.677 inches long; for 3-inch decks, 2.145 inches long. (b) Through-bolts are also made in two types. One type has a square portion immediately under its head. The other type has a saw cut under its head. The square type is more generally used. The square section prevents the bolt from turning when being driven into the wood. Either hexagon or square nuts are used with through-bolts, and a washer is installed under each nut. The bolt, washer, and nut are made from galvanized iron. The bolts are packed with hemp and dry lead. (2) Laying a wood deck. A wood deck must be laid in a dry condition. An awning should be erected for protection against rain. Planks normally are laid longitudinally, except in narrow transverse passageways (approximately 9 feet wide by 1% feet long), where they can be laid transversely. The butts of the planks should be alternated. Between two butts installed at equal lengths, there should be at least three continuous planks. The butts of two adjoining planks must not be in the same frame spacing. (a) Procedure for using welded bolts. When laying the planks, start at the centerline of the deck and work toward the sides. A section containing four or five planks should be worked at a time. Position the planks so that the seams are parallel to the centerline of the vessel. The planks can be wedged up using the lugs welded to the deck. Bore holes in planks while planks are wedged up. Remove planks and weld bolts to the deck. Rebore holes in planks so that nuts can be installed. The depth of reboring depends upon the thickness of planks. For 2-inch planks, rebore to a depth of approximately 0.897 inch, and for 3-inch planks rebore to a depth of approximately 1.287 inches. Cover deck with a thick coat of red lead or a bituminous substance, such as deckduthon, maxoid, or synthaproof, AGO &244A . and sprinkle with dry cement. Place planks on welded bolts and install washers and nuts. Note. If deck-duthon is used to coat deck, the steel deck must be covered with an adhesive solution, Military Specification MIL-G-413, prior to applying deckduthon. (b) Procedure for through-bolts. When through-bolts are used, the planks are first lined out and holes drilled in the steel deck. Arrange four of five planks and bore holes in them from the bottom with an auger. Install planks in a similar manner as used for welded bolts, with the following exceptions: Before installing nuts, wedge up planks. Place a ring of hemp and white lead underneath head of each bolt and underneath washer, if required. After planks have been installed, plug holes with dowels covered with white lead or marine glue. The dowels should be made from scrap ends obtained from planks. (3) Calking and paying. After the entire deck is laid out, it is calked. Calking can be accomplished manually with a calking iron or mechanically with pneumatic calking tools or calking machines. Manual calking is preferred to mechanical calking because mechanical calking is apt to damage the upper edge of the calking seam and impair the quality of the wood deck. (a) A cotton thread, two or more threads of oakum, and plucked and tarred old hemp rope are installed in the calking seam. The cotton thread is sometimes omitted. At least two threads of oakum are required, generally one thread per 0.975-inch thickness of the plank. (b) A calking machine forces the oakum into the calking seam with a chisel driven by an electric motor. At the ends, along deck houses, and places where there is not sufficient room for the machine, calking must be done by hand. (c) After calking, the seams are sealed AGO 6244A with hot pitch, marine glue, or a similar substance. The seams are overfilled so that after coagulation, there will be a projecting rim left above the wood. Guttaterna, a rubber product, can be used to seal the seams. When using Guttaterna, one thread of oakum will suffice for calking. The seam will become slightly concave or convex, but, as a result of the strong adhesive power and elasticity of Guttaterna, the seam will be watertight. Heating and the application of Guttaterna should be done with the greatest possible care. It is therefore advisable to follow specific instructions for its use from the manufacturer. (d) It is also possible to omit the oakum entirely and use Secomastic. Secomastic is composed of natural and processed oils compounded with graded inorganic fibers and diatomaceous fillers. Itis a flexible base for the marine glue. It remains sufficiently elastic to accommodate any normal expansion or contraction of the joint. It is sufficiently adhesive and is unaffected by temperatures is supplied ready for use in carup to 200° F. (93° C.). Secomastic is supplied ready for use in cartridges; no heating or thinning is necessary. It is applied between the planking by the use of a Seco patent hand-pressure gun or a compressedair pressure gun. (e) Perma-calk is sometimes used. When applying this substance, no use is made of oakum, marine glue, or any other liquid. Sealing the joints is done by means of a specially made strip of synthetic rubber. For these strips, fi,tting grooves are planed in the planks. The grooves in the crosscut ends are made after the planks have been cut. In using this method, four or five planks are laid simultaneously with the strips in the joints. After this portion has been firmly wedged up, the bolts are welded to the deck with aid of a stud welder, and the planks screwed down. (4) Finishing the wood deck. The wood deck is finished by first having the excessive material scraped off, then entirely planed with the use of an electric planer. In areas where the machine cannot be used, planing is done by hand. After planing, the wood deck is washed with water. In places subject to wear, for instance near staircases and before doors, six or eight slats of about 1.170-inch width, 0.975-inch thickness, and approximately 0.975-inch spacing ar~ screwed on the wood deck. The length of these slats is equal to the width of the staircase or the doors. 48. Deck Fittings and Hardware All vessels have an assortment of deck fittings and hardware, mounted on the upper deck, for such purposes as anchoring and mooring, loading and unloading cargo, taking on fuel and water, and providing access and ventilation to the v;rious compartments below. Deck fittings are described in chapter 14. 49. Ceilings and Coaming All single and double bottom vessels must have a ceiling. In double bottom vessels, the ceiling serves as protection of the double bottom. It also protects the cargo from minor leakage from water and oil through the plating bottom. In single bottom vessels, the ceiling is laid on the floors from the centerline keelson to the upper part of the bilges. As far as possible, the ceiling will be laid under hatchways or otherwise will be fastened to the reversed frames in such a way that they are easy to remove for inspection of the shell. Ceilings in double bottom vessels must be laid over the bilges and under hatchways. The ceilings over the bilges must be easy to remove. If the manhole covers project above the double .bottom, they must be protected by a steel coaming around each manhole, fitted with a hatch of wood or steel. If the ceiling is laid directly on the double bottom, the plating must be coated with Stockholm tar and then dressed with cement. If the ceiling is not laid directly on the plating, a %-inch space must be left between the plating and the underside of the wood to allow water leakage to drain to the bilges. The ceiling is placed on transverse laths 3 inches wide and lj2 inch thick. They are laid on each frame and under the hatchways, athwartships, so that water or oil leakage can drain to the bilges. The laths are not fastened to the double bottom, but kept in place by pieces of flat bar welded to the bottom. Sometimes each tenth plank of the ceiling is provided with a countersunk ring to allow for removal of the ceiling for inspections. Each steel coaming hatch is provided with two such countersunk rings. Because the ceiling planking is not usually calked, repairs to ceilings are simplified. Section IV. SUPERSTRUCTURES 50. General Superstructures are generally defined as the enclosed structures built on or above the weather deck. These superstructures normally include the fo'c'sle, poop, and bridge structures. The fo'c'sle is the structure built above the bow of the vessel. The stern erection or structure above the weather deck is the poop. The largest structure, located amidships, is called the bridge and usually includes the galley, messroom, quarters, bridge, charthouse, and wheelhouse or pilothouse. 51. Bridgehouse and Bridge The bridgehouse is usually a three-deck or four-deck structure, consisting of a deck house, boat deck, and bridge deck. In a four-deck structure, the top of the wheelhouse is called the flying bridge. The bridgehouse contains ac commodations for the crew and quarters for the officers, in addition to the wheel house and charthouse. 52. Cabin Trunks Trunks are vertical or inclined shafts, formed by bulkheads or casings extending one deck or more in height, placed around the openings in the decks. Trunks provide access to the hold and cargo stores and allow ventilation without disturbing or interfering with the AGO 5244A contents or arrangements of the adjoining spaces. 53. Deck Houses The deck house is the lowest enclosure in the bridgehouse and is a partial superstructure that does not extend from side to side of a vessel. It rises from the weather deck and is generally used by the crew. It can include crew quarters, messrooms, pantry, galley, cleaning gear lockers, and office space. 54. Outfit Lockers Outfit lockers are located at various stations throughout the vessel to accommodate miscellaneous equipment such as fire hose, foulweather gear, and life preservers. 55. Masts A mast is a long pole of steel or wood usually circular in section, one or more of which is erected vertically on the centerline of the vessel. The mast can be in one piece or it can be a series of pieces bonded together to form one continuous pole. Masts are used as supports for the rigging, cargo handling, and radio antenna. The bottom of the mast is called the heel and the top is called the head. The mast is set on a deck below the shelter deck and cased in a box or case called a mast housing. The heel of the mast is set on a stool or a socket, to give it a proper footing. In small vessels, the mast is sometimes stepped into a center keelson. When a wooden mast is used, a steel ring is fastened to the deck. It is secured to the deck transverse girders with the proper tilt to fit the rake of the mast. The masts are held rigidly by steel wire cables. 'l'o facilitate loading, unloading, and cargo handling, booms are attached to the masts. A winch is usually provided where heavy cargo loads are anticipated (fig. 58). 56. Cranes Some vessels use cranes rather than booms for handling cargo. Three types of cranes used are a crane mounted on the centerline between two hatches and capable of working the ends of both, a crane mounted over the center of a hatch and extending over the side of the AGO 5244A MAST OR KINGPOST WHIP CARGO HOOK Figure 58. Mast and boom details. vessel, and a sideport crane mounted in the overhead of the 'tween decks with the crane boom extending over the pier. 57. Ventilation The word VENTILATION in vessels means the combined functions of heating, cooling, and ventilating. The installation of these systems necessitates cutting holes through the decks and bulkheads which, even though protected by enclosures, become a potential threat of flooding (ch 14). The purpose of ventilation, in addition to the comfort of the crew, is to aid in cooling cargo stores, ammunition, electrical equipment, and engine rooms. Conversely, it serves to heat these areas when heat is needed. The system contains many ducts, fan blades, fan casings, cooling coils, and fittings. All of these items collect dust, dirt, and grime. A complete cleaning of the system, including ex haust screens, should be accomplished at least weekly, as follows: a. Stop fan. b. Open all access plates in secured system. c. Brush dirt and lint from coil fins and fan blades with a wire brush, carefully handled to avoid fin and blade damage. d. Use a nontoxic cleaning agent if excessive grease and dirt has accumulated. e. Vacuum all accessible areas in system. f. Wash exhaust screens and air filters in dish washing machine, rinse thoroughly, and dry by applying a stream of compressed air. g. Clean flame arrester cells in same manner as air filters. h. Observe, when replacing components into system, that fittings and closures have the same degree of watertightness as decks and bulkheads that they pierce. i. Check all closure valves for proper operation after reinstallation. j. Observe that rubber gaskets and screw threads on locking clamp bolts are free of dirt, corrosion, and paint. k. Check the system thoroughly, after cleaning and reassembly, insure that watertight integrity is maintained. Section V. CORROSION, DRY ROT, MILDEW, DECAY, AND ELECTROLYSIS 58. Corrosion a. General. The extent of corrosion is reduced to the least possible minimum by the use of metals that are highly resistant to corrosion, as well as consistent with strength and weight. The amount and degree of corrosion are dependent upon many factors, most of which can be attributed to two causes: the salt content of the air and the fabrication processes. Whether or not the vessel is painted, the types of materials used for protection against corrosion, treatment of parts, and dissimilar metal contacts are all factors concerning fabrication processes. b. Miscellaneous Corrosion. Other factors which can cause corrosion are exhaust and gunfire gases and battery acid. To guard against corrosion, aluminum alloys are usually painted or anodized or both. Steel, with the exception or corrosion-resistant steel alloys, requires cadmium or zinc plating. Magnesium alloys requires chemical baths or chemical baths and paint. Coating both sides of the aluminum alloy sheet with chemically pure aluminum will be the most effective means to prevent corrosion. This coated material is known as clad aluminum. Under normal conditions, when not in contact with salt, salt spray, dissimilar metal, or harmful chemicals, this type of sheet is highly resistant to corrosion. Unpainted clad aluminum is easily distinguished from anodized aluminum-alloy sheet. It has a bright, highly polished surface, whereas anodized aluminum alloy is characterized by a lack of metallic luster. Variations in the alloy and processing result in anodized surfaces ·having different degrees of glossiness and various shades of gray and yellow. c. Superficial Corrosion. This is the least serious type of corrosion, but it can become quite serious it allowed to continue without corrective action. Surface pitting of unpainted aluminum does not signify deterioration of the metal unless the cladding has been pierced or worn away by abrasion through contact with another surface. Close examination will prove the corrosion to be of the cladding only. On clearing away the corrosion deposits, a slight etching will be shown. The coating, therefore, protects the alloy core even if a slight surface corrosion is evident. Under severe corrosive conditions, the clad coating will have been partially corroded. On the surface, the corrosion has the appearance of hills and valleys (fig. 59). d. Dissimt'lar Metals Corrosion. Every metal has a certain inherent electrical potential. When one metal is placed in contact with a metal of a different potential with the presence of moisture and an electrolyte, an electrical current flows from one to the other. This gives rise to chemical by-products and causes the dissolution of one of the metals. The metal from which the current flows is the anode, and AGO 5244A Figure 59. Typical surface appearance of superficially corroded, unpainted aluminum sheet. the metal to which the current flows is the cathode. Qualitatively, the severity of corrosion, caused by a dissimilar metal contact in the presence of a corroding medium, can be predicted from the potential difference of the metals making up the cell. The greater this difference, the more severe the corrosion of the negative metal. The galvanic series listed in table IV indicates the potential differences among the dissimilar metals listed. Those metals furthest apart on the list will tend to have the greatest potential differences and will tend to be more severely corroded due to electrolytic action. Quantitatively, table IV is not true in every respect. The corrosion is proportional to the current flowing in the cell and is influenced by polarization of the electrodes, cell resistance, ratio of contact areas, concentration, aeration, and type of corrosive medium, as well as the driving potential. For example, sea water is not the same all over the world. It is influenced by many things such as proximity to fresh water outlets, currents like the Gulf Stream, and the amount of rainfall. Because the predominant salt in sea water is generally sodium chloride, the strength of the electrolyte, and thus the degree of corrosive action, will depend uppon the location. In certain locations, salts other than sodium chloride can predominate in sea water causing a reversal of polarity of the contacting metals and thus an entirely different electrolytic corrosion. Calcium chloride, which is used to melt ice or to absorb moisture, is also a strong reagent. When combined with water, it forms a strong electrolyte. Table IV. Galvanic Series in Sea Water Corroded End (Anodic) 1. Magnesium 19. Muntz metal 2. Magnesium alloys 20. Manganese bronze 3. Zinc 21. Naval brass 4. Galvanized steel 22. Nickel (active) 5. Aluminum (5052, 6061, 3003, 1100, 5053, in this 23. Inconel (active) order) 24. Yell ow brass 6. Clad 2024 and clad 2017 25. Admiralty brass 7. Cadmium 26. Aluminum bronze 8. Aluminum (7075, 2117, 2017, 20024, in this order) 27. Red brass 9. Mild steel 28. Copper 10. Wrought iron 29. Silicon bronze 11. Cast iron 30. Ambrac 12. Ni-resist 31. 70-30 copper nickel 13. 13 percent chromium stainless steel type 410 (ac 32. Comp. G-bronze tive) 33. Comp. M-bronze 14. 50--50 lead-tin solder 34. Nickel (passive) 15. 18-8 stainless steel type 304 (active) 35. Inconel (passive) 16. 18--8--3 stainless steel type 316 (active) 36. Monel 17. Lead 37. 18--8 stainless steel type 396 (passive) 18. Tin 38. 18-8--3 stainless steel type 316 (passive) (1) Iron chloride. The product of corro which would be predicted by the posi sion, such as iron chloride in the case tion of the metals in table IV. In the of steels, can cause an actual increase aluminum and noncorrosion~resisting in the rate of corrosion beyond that steel couples, the iron chloride which AGO 6244A 57 develops during the corrosion process generally increases the rate of corrosion beyond that of aluminum and nickel couples which would normally tend to be corroded at a faster rate. (2) Precautionary measures. In general, the problem resolves itself into using metals with as small a potential difference as possible, making use of proper plating or chemical treatments. Some treatments are zinc or cadmium plating on copper or iron alloys in contact with alluminum alloys, anodizing on aluminum alloys, dichromate treatments on magnesium alloys, and using insulation or inhibitive paints, such as chromate tapes and zinc chromate primer in faying surfaces. (3) Miscellaneous examples. The degree of corrosive action on dissimilar metals, due to galvanic reaction, is expressed in relative terms in tables V and VI. These tests were made to determine the effect on various metals after a 6-month exposure to sea water. These tests showed that naval brass, coupled with either clad 2024 aluminum or 2024 aluminum alloy and not protected at the faying surfaces with a primer or coat plating, produced severe corrosion. Cadmium-plated brass, coupled to clad 2024 aluminum or to 2024 aluminum alloy with a primer coat of zinc chromate on the faying surfaces, was practically free from corrosion after a 6-month exposure. Iron oxide primer used on the faying surfaces showed slightly less value than zinc chromate as a corrosion inhibitor in these tests. Refer to tables V and VI. The dissimilar metals which can start galvanic action need not be an integral part of the structure or structural repair. Any foreign article (accidentally, or otherwise), left in contact with part of the structure can very readily cause corrosion. This type of corrosion has also been caused in numerous instances by someone accidentally dropping washers into enclosed and inaccessible \ parts of the vessel where water could collect and cause galvanic action. The drillings or filings from some repair job, if not cleaned away, can also readily cause dissimilar metals corrosion. Although definitely contrary to good shop practice, cases have been found where steel wool was used to rub down the priming coat. It is impossible to clean steel wool completely off the metal surface, as bits of steel will be left embedded in the primer and then sealed in when the final paint coat is applied. This will cause galvanic corrosion. Aluminum wool should be used in the cleaning of painted or unpainted aluminum surfaces. Caution: Steel wool should not be used on any aluminum parts under any conditions, as it can be injurious to equipment. Table V. Corrosion Test of Naval Brass Attachments on Aluminum Alloy and Clad Aluminum NAVAL BRASS ATTACHMENTS 2024 aluminum 2024 clad alloy aluminum Metal-to-Metal Very Bad Bad Iron Oxide Primer "Rery Bad Bad Zinc Chromate Primer Fair Good Table VI. Corrosion Test of Cadmium-plated Naval Brass Attachments on Aluminum Alloy and Clad Aluminum CADMIUM-PLATED NAVAL BRASS ATTACHMENTS 2024 aluminum 2024 clad alloy aluminum Metal-to-Metal Fair Good Iron Oxide Primer Fair Fair Zinc Chromate Primer Excellent Excellent e. Corrosion by Condensates. Another cause of corrosion is the action of exhaust gas condensates on the metal. Condensation from gunfine gases, unburned gunpowder particles, and battery acid is also in this category. These all consitute strong electrolytes, and galvanic action starts as a result. AGO 6244A f. Intergranular Corrosion. This is a type of corrosion not easily detected, and in its early states there is no way to detect it unless a microscopic examination is made of properly prepared specimens. Intergranular corrosion usually results from imperfect heat treatment and occurs principally in unclad 2024 type of alloys. It is a type of corrosion which progresses among the grain boundaries of the alloy and can even penetrate through the section in the case of sheet stock. It is the most dangerous type of corrosion that can occur to sheet aluminum because the strength can be lowered considerably without any surface indications. g. Stress Corrosion. This type of corrosion occurs when a particular member is subjected to excessive stress and a corrosive condition. It is evidenced by the metal cracking in the area of maximum stress. Although it happens infrequently, it will occur in any metal that is subjected to a sufficiently high stress. Aluminum, brass, and magnesium alloys are particularly susceptible to this type of failure. Stress corrosion will occur along the lines of cold working if the metal has been stressed too highly and is not relieved through proper treatment. h. Corrosion due to Contact with Water-Absorbent Material. Although modern vessel structure may have instances where waterabsorbent materials such as wood, cork, sponge rubber, felt, and asbestos are used in contact with metals, they can be a source of serious corrosion unless proper protective measures are applied. These materials can absorb enough water and hold it in contact with the metal long enough ,to cause corrosion. In maintenance of vessels, all metal areas covered by nonmetallic material thought to be water-absorbent should be inspected periodically for corrosion. When replacing or reattaching such materials, proper steps should be taken to insulate them from the contacting metal surface by paint coats or zinc chromate paste. 59. Dry Rot Dry rot is the decay of seasoned timber caused by fungus that consumes the cellulose of wood, leaving a soft skeleton which is readily reduced to powder. When dry rot occurs on a AGO 6244A vessel that is in use, the rot become very difficult to repair. The suspected area contaiinng dry rot should be tested with a sharp tool. Sound wood is solid and difficult to penetrate, where as decayed wood is soft, easily penetrated, and usually of a darker color than the original material. After the dry rot has been discovered and removed, the entire area should be treated with a preservative to prevent the rot from starting anew. Replace members that have been removed with pretreated, sound, new wood. a. Cause of Dry Rot. Dry rot is caused by rain water seeping into a hairline crack and working down between two members where it is trapped so that it cannot evaporate. This spot can often be a considerable distance from the point of entry. When the crack is located, pour preservative into it, and then seal it with good seam compound or trowel cement. b. Removal of Diseased Timber. The area affected by dry rot, as well as a considerable distance beyond, should be cut from the vessel. Wheer possible, replace the whole member rather than a section. One of the troubles involved is the removal of fastenings, for often they are inaccessible or on the wrong side of the member. Where drifts are encountered, the wood must be split off and a hacksaw used. A professional shipwright should make all repairs where there is diseased wood. c. Treatment of Diseased Wood. Once the affected parts have been removed, they should be burned. All surrounding areas should be drenched with a preservative. All new replacements should be well soaked, after they have been fitted and before they are installed. Warning: Most preservatives are highly toxic and very inflammable and ,therefore injurious to personnel and equipment. d. Replacement of Removed Members. When engaged in new construction, or making alterations, insure that joints are tight and are put together with waterproof glue or bedding compound. Wood preservative should be used during the entire replacement operation. 60. Mildew Mildew growth, known as rot, mold, or fun gus, affects almost all materials of plant or animal origin. Mildew grows from small bodies known as spores, which exist in the soil and decaying vegetation. They are carried on slight air currents, which deposit them on all exposed surfaces where, if conditions are favorable, they germinate like seeds and grow. Many different species of mildew are in existence. The species vary widely, and the rate of deterioration depends upon the material involved and extent to which local conditions favor the growth of mildew. a. Conditions for Mildew Growth. The following conditions cause abundant mildew growth: mildew spores, the source of infection; presence of some food for mildew; moisture; and heat, although quite often very little is needed. Foods include fats, greases, waxes, oils, lint (small particles of cotton, wool, or other fabric), dirt, and vegetable and animal substance. b. Destroying Mildew. Saturate a cloth with a suitable preservative. Carefully wash down all affected surfaces and repaint. As protection against recurrence of mildew, add an antimildew additive to paint. 61. Decay Decay is often concealed and occurs in those portions of the vessel which are poorly ventilated and where fresh water has gained access. Normally, these portions are confined to the stern and transom areas, that region directly beneath the coverboard, and to the bilge region in hulls having tight platform decks. The headers beneath superstructures and . filler blocks also warrant careful inspection, as well as that portion of frame and plant near the waterline of hulls in fresh water service or storage. Beam ends, beam end connections, and plywood used as decking and subdecking must be closely inspected. a. Recognition of Decay. Decay is usually not recognizable by visible fungus growth, except in joints between faying surfaces. There are several aids to recognition, however, which can be employed. If paint coatings are discolored or the wood surface cupped, decay can be suspected. A sharp ice pick or an oyster knife can be used to detect decayed wood by the ease of penetration and removal. Recognizable decay is most likely to be found near faying surfaces and joints. The condition of large timbers can be best determined be drilling to two thirds their depth with a %-inch drill. In doubtful instances and when practical, wood specimens can be submitted to a laboratory for positive determination of decay. Black stains spreading along the grain from ferrous metal fastenings are usually caused chemically by the iron contact instead of decay fungus and have little effect on strength. b. Examination of Structure for Decay Repairs. (1) Description. Vessels in salt water show markedly less decay requiring repairs than those serving in fresh or brackish water. Vessels that do not require decay-type repairs in seven or eight years will usually not show decay, providing the area of service has not radically changed. Those hulls having heavy-sawed frames and tight ceilings, tight inner sheathings, in their construction are especially susceptible to decay. Therefore, before a decision is reached on how thorough an inspection should be, a review of the repair record should be made. A determination should be made of the type of construction and whether service has been in salt, fresh, or brackish water. (2) Inspection. (a) At 4-year intervals, inspection should be made of all areas described in the repair record by probing or sounding. If decay is suspected, the frame heads, beam ends, stem, planking, and other members should be bored as conditions indicate. Planking strakes selected for boring should be at, or a few inches above, the waterline in the stemtransom areas. Borings should be made about eight inches from the butted ends and extend to the faying surfaces between inner and outer planking. If boring discloses infection other than localized, inspect as follows: (b) Pull a strake near waterline, extending aft from stem on one side AGO 5244A and forward from stern on opposite side, for approximately one fourth the length of hull. If appreciable amounts of decay are found, repeat on other side of hull and continue removal of strakes until decay is no longer evident. In double planked hulls, if inner plank is fore-and-aft, removal should include two strakes of outer and one of inner plank to permit dired examination of frames. If inner plank is diagonal, remove strake and probe, bore, or sound to determine extent of decay of planks and frames. Stem should be bored just below deck line as well as below platform deck. (c) Beams ends, end connections, and frame heads must also be examined by removal of lock strake, plank sheer, sheer strake, or strake below sheer strake. Strake removed should extend aft from s~tem on oneside of first watertight bulkhead. (d) All holes bored for inspection purposes must be plugged with seasoned dowels which have been soaked in preservative and allowed to dry. Dowels are cut %4 inch undersize and heavily coated with resorcinol glue prior to being driven into the full depth of the drilled hole. Borings must never be too numerous or so located as to impair hull strength. c. Corrective Measures. Three fundamentals of decay prevention are the following: The use of dry lumber and any method to maintain this dryness after installation; the use of all heartwood lumber of a decay resistant species; the use of wood preservative chemicals. The following functions must be taken into consideration for corrective action: (1) The addition of well placed ventilators or the extension of the existing mechanical ventilation systems to unventilated compartments. (2) The alteration of tight platform decking, ceiling (inner sheathing), or filler blocks to permit air circulation AGO 5244A to the bilges and between bays at the frame head level. Platform decks in compartments without inner sheathing should terminate at the inboard faces of the frames and strakes of ceiling and %,-inch wire mesh employed to prevent trash accumulating in the bilge. In the event ceiling is removed to provide ventilation, ~wash boards must be installed in bilges to restrict the motion of bilge water in critical areas such as machinery 11paces. (3) The correction of any feature interfering with complete water runoff. ( 4) The removal of refrigerator compartment insulation which lies against the hull or deck plank. When the refrigerator compartment is rebuilt, the outer sheathing should extend no further than the inboard face of the frames. The outer sheathing at the top of the compartment should terminate at the lower face of the deck beams. The bottom sheathing should be raised about four inches off the platform deck and 16-gage wire mesh used to prevent trash accumulation and rat nesting beneath the compartment. Vapor barrier material, with all joints tightly sealed, should be installed on the outer face of all refrigerator compartment outer sheathing, if practical. If not, the vapor barrier material should be installed on the inner face of the outer sheathing. The sheathing should be Class 1 or Class 3 pressure treated plywood. ( 5) When repair work is undertaken, no major change in the design of a vessel should be made without approval. 62. Electrolysis Electrolysis is the chemical decomposition of metals by the action of an electric current. Causes and control of electrolysis are discussed in chapters 5 and 9 respectively. a. Detection of Electrolysis. The first sign of trouble can be a battery which runs down without being used, or runs down faster than usual. A portable volt-ohm milliammeter is required to make the necessary check. (1) To check current leakage, the following checks should be perpetrated: (a) Insure that nothing has sagged out of place over battery or otherwise contacted terminals. (b) Wipe off top and case and inspect for fluid leakage. Caution: If the case is cracked, remove the battery, clean up the spillage and neutralize any acid in the area with baking soda. Broken batteries should be replaced at first opportunity. (c) Turn off every electrical device aboard, but leave in fuses and main switches. Note. One terminal of the battery, which can be positive or negative, will be grounded to the engine. The other terminal should be disconnected. (d) Switch volt-ohm milliammeter to highest current range, approximately 10 amperes, connect it between connected battery terminal, and disconnected lead, arranging meter wires so the one going to battery post is the same polarity as the battery. Note. No current should flow. (e) Switch meter down through successively lower milliampere ranges, watching for pointer deflection. Note. No current :flow will show, even on the 10-milliampere range. Vessels with old or damp wiring could have, however, a few milliamperes leakage. Caution: A few milliamperes are not immediately dangerous; however, any wiring or fixture repair must be performed by a qualified marine electrician. (2) Whether or not the leakage current found is dangerous depends not only upon its magnitude but also upon where it is located. Different metals are destroyed at different rates, but an idea of the speed of decomposition for given values of current can be gained from the fact that copper dissolves at the rate of 0.00004 ounces per hour, per milliampere of current flow. b. Corrective Measures. ( 1) Figure 153 shows a common installation where the flow of spray currents through the water can result. The :fixture to which the battery is connected can be a radiotelephone and its ground plate, an electric toilet, a pump, an auxiliary generator, or any other electrical device which contacts the water. At first glance, all connections appear to be proper. If the grounded wire from the fixture to the engine is too small, or if either of its connections is faulty, however, a voltage drop or difference of electrical potential will exist between grounded engine fittings and the external fixture. Current will flow through the water, as indicated by the dotted lines. The end of the circuit which is positive in polarity will deteriorate. This condition can be checked by measuring for voltage, low range on the meter, between the ends of a circuit when the fixture draws current. If any voltage is indicated between the ends of a ground circuit, heavier wire should be installed or the terminals tightened until the reading is zero. (2) Figure 60 illustrates a condition where the ground conductor wire is heavy enough, but bad insulation on the hot wire applies battery voltage in stray circuits to other grounded objects. If they are contacted by a hot battery wire, iceboxes, metal blower or heating ducts, on any other metal objects in contact with water, either outside or in the bilge, can act as electrodes for stray circuits. If the insulation defect leading to this condition is a burned spot or an abrasion, heat can be generated at the point of contact, which could also be dangerous. Leakage can also take place directly from the wire, through bilge water or wood saturated with moisture. When insulation leaks because it AGO 6244A is damp, the positive wire will begin to deteriorate and can soon fail entirely. Wires which appear to have lumpy-green incrustations should be suspected as being affected by cause of electrolysis. Defective wire should either be dried off, properly insulated, or replaced. (3) Figure 61 shows the most dangerous condition, a cross-connection of the hot and grounded terminals of two fixtures. When this hookup is made, the entire battery voltage appears between the underwater fittings. Fittings can lose as much as 25 percent of their weight in an hour. This usually occurs when several wires are connected directly to the battery terminals, and batteries are removed or reconnected by personnel unfamiliar with electrolysis. Only main cables should attach to the battery terminals, and only qualified personnel should perform maintenance on electrical circuits. ( 4) Overcurrent devices will not normally be placed in any permanently grounded conductor with the following exceptions: Figure 60. Typical illustration of bad insulation causing stray circuits. Figure 61. Typical cross-connection of hot and grounded terminals of two fixtures. (a) Simultaneous overcurrent devices which open all conductors at the same time. (b) Protection of operating motors where certain types of alternating current applications, using wyedelta or delta-wye transformers, are employed. Section VI. DECK COVERINGS 63. General The requirements for a satisfactory deck covering on vessels include one having lightweight qualities, nonflammability, good resistance to wear, ability to protect the steel deck from corrosion, slip-resistant properties, good appearance, and ease of maintenance. Simple application and economical cost are also important considerations. Deck coverings are classified on the basis of use aboard the vessel. When a material is restricted to a particular class of vessel, this is included in the classification. a. General Safety Precautions. Certain adhesives and compounds utilized in the application of deck coverings contain flammable solvents. Adequat~ saf~ty and health measures, AGO 6244A depending upon the flash point and toxicity, should be taken. b. Extent of Coverage. The deck covering should cover the entire deck of the · compartment except under enclosed built-iii furniture and under equipment with enclosed foundations. If desired, resilient tile can be squared off at stiffeners, except at doors, and the bare steel portion of the deck painted a harmonious color. (1) Temporary. Temporary coverage is applied in an emergency or in a situation where permanent coverage cannot be obtained. (2) Permanent. For the application of permanent coverage, refer to the methods specified in table VII. c. Deck Paint in Conjunction with Coverings. Decks for which coverings are specified do not require painting, "except around slip-resistant cloth treads or where the deck covering consists of false deckings, gratings, rugs, or portable mats. Areas for which no deck covering is specified should be painted as required by TB 7 46-93-4. Deck paint should not be applied over deck coverings. Slip-resistant materials can be painted with deck paint thinned with paint thinner to the consistency of a stain. Paint stain should not be used over slip-resistant deck coverings on flight decks because of the critical nature of flight deck operatio11s. d. Applications, Locations, and Approved Materials. Table VII lists the applications, locations, and approved materials to be used when applying deck coverings. Table VII. Applications, Locations, and Approved Materials Location Material 1. Exterior (surface vessels-steel): Traffic areas ---------------------------------------------------- Waterways at gangways (wood decks) --------------------------Wood surfaced areas -------------------------------------------Working areas (areas outside of direct traffic routes surrounding topside equipment such as fire control stations, gun circles, lookout stations, director platforms, areas around deck machinery, crafts, and replenishment-at-sea stations). 2. Interior (surface vessels-steel): Ammunition stowage, handling room, ready service room (in traffic and working areas only). Auxiliary battle dressing station ---------------------------------Bath ----------------------------------------------------------Battledressing station ------------------------------------------- Bread room ----------------------------------------------------Butcher shop (except meat thawing area). ----------------------Butcher shop (meat thawing area) -----------------------------Captain's stateroom, cabin, and sea cabin ------------------------Captain's galley -----------------------------------------------Captain's plot -------------------------------------------------Chief of Staff cabin, stateroom, and sea cabin --------------------MS galley (outside steam kettles) -------------------------------- MS galley (within coaming under steam kettle) ------------------- MS living space ----------------------------------------------- MS lounge ----------------------------------------------------- MS washroom, water closet, and shower space --------------------Crew galley (outside steam kettle) -----------------------------Crew galley (within coaming under steam kettle) ---------------- Crew library --------------------------------------------------Crew living space ---------------------------------------------Crew messroom -----------------------------------------------Crew recreation area ------------------------------------------Crew shelter and food service pantry ----------------------------Crew washroom, water closet, and shower space -------------------Crypto room ------------~--------------------------------------Division commander cabin and stateroom ------------------------Executive officer cabin and stateroom ---------------------------Flag cabin, stateroom, and sea cabin ----------------------------Flag galley ----------------------------------------------------Flag o'ffi.ce --------------------------------------------------·---Fog foam injections station (within coaming) --------------------- Garbage disposal room ----------------------------------------lee making room ------------------------------------------------Ladies room --------------------------------------------------- Slip-resistant covering (see note 1) Aluminum grating Wood decking Slip-resistant covering Slip-resistant covering Deck tile Deck tile Deck tile Deck tile Magnesite CRES PAN Rug and pad (see note 2) Deck tile Deck tile Rug and pad Deck tile; magnesite if steam kettle present CRES PAN Deck tile Deck tile Rubber terrazzo Magnesite CRES PAN Deck tile Deck tile Deck tile Deck tile Deck tile Rubber terrazzo Deck tile Rug and pad Rug and pad (see note 2) Rug and pad Deck tile Deck tile Rubber terrazzo Rubber terrazzo Rubber terrazzo Deck tile Table VII. Applications, Locations, and Approved Materials-Continued Location 2. Interior (surface vessels-steel)-Continued: Laundry (within coaming) -------------------------------------Laundry, issuing and receiving room ----------------------------Motion picture projection room ---------------------------------~avigator sea cabin and stateroom ------------------------------Offices --------------------------------------------------------- Officer washroom, water closet, and shower space _________________ Passages (serving living, messing, medical, and office spaces) _______ Pharmacy ----------------------------------------------------Post Office ----------------------------------------------·------Scullery ------------------------------------------------------- Senior staff officer cabin and stateroom --------------------------Senior staff officer galley ---------------------------------------Senior staff officer mess room ----------------------------------- Vessel control spaces (pilothouse and chartroom communication spaces). Ship store -----------------------------------------------------Shops (walking areas around power tools) ------------------------Troop commander cabin and stateroom (not aviation) _____________ Stateroon1 ------------------------------------------------~----Stearn kettles (within coarning) ---------------------------------Steering stations ----------------------------------------------Steward living space ------------------------------------------Tactical command cabin and stateroom --------------------------Troop living space --------------------------------------------Troop rnessroorn ----------------------------------------·-------Vegetable preparation room -------------------------------------VVard bath -----------------------------------------------------VVardroorn bunkroorn ------------------------------------------VVardroorn galley (outside steam kettles) -------------------.------ VVardroorn galley (within coarning under steam kettles) ___________ VVardroorn lounge --------------------------------------------- VVardroorn rnessroorn ------------------------------------------- VVardroorn pantry --------------------------------------------- VVatch stations ------------------------------------------------ 3. Miscellaneous (surface vessels-steel and wood): Dry sides of doors to weather and washrooms ---------------------Operating and servicing areas in way of electric and electronic equipment (for prevention of electric shock). At each side of door with high coarning normally used for continuous traffic, and at the head and foot of ladders at each side of door in crew's rnessroorn. VVeather decks of steel vessels where corrosion is an extreme problem and weight is acceptable. 4. Exterior (wood vessels): Main deck ------------------------------------------------------ Repair of leaky decks --------------------------------------------Upper levels --------------------------------------------------- 5. Interior (wood vessels): Captain's stateroom and cabin ----------------------------------Commissary spaces --------------------------------------------- Crew living space -----------------------------------------------Crew rnessroorn ----·---------------------------------------------Crew washroom and water closets --------------------------------Executive Officer's stateroom and cabin ----------------------------Foam proportioners (stationary and within coarning) -------------- AGO 5244A Material Rubber terrazzo Deck tile Deck tile Deck tile Deck tile Rubber terrazzo Deck tile Deck tile Deck tile Rubber terrazzo; Rug and pad Deck tile Deck tile Deck tile and fiber mat at weather door. Deck tile Slip-resistant covering Rug and pad Deck tile Corrosion-resisting steel pan VV~tch station mat Deck tile Rug and pad Deck tile Deck tile Rubber terrazzo Rubber terrazzo Deck tile Magnesite CRES PA~ Deck tile, rug, and pad (see note 3) Deck tile Deck tile VVatch station mat Door mat, portable Rubber matting Cloth treads (3 treads) Rubber mastic ~o deck covering Polyester glass or Celastic Slip-resistant covering (epoxy) Linoleum or deck tile Ceramic tile Linoleum or deck tile Linoleum or deck tile Ceramic tile Linoleum or deck tile Polyester glass Table VII. Applications, Locations, and Approved Materials-Continued MaterialLocation 5. Interior (wood vessels)-Continued: Ceramic tile Laundry ------------------------------------------------------- Linoleum or deck tile Offices --------------------------------------------------------- Linoleum or deck tile Pharmacy ---------------------------------------------------- Ceramic tile Scullery --------------------------------------·----------------- Linoleum or deck tile "essel control spaces ------------------------------------------ Shops (walking areas around power tools) ----------------------Cloth treads Shower-stall deck and bulkheads --------------------------------Polyester glass and shower mat Steam kettles (within coaming) --------------------------------Corrosion-resisting steel pan Watch station mat Steering stations ---------------------------------------------- Wardroom living space ----------------------------------------Linoleum or deck tile Linoleum or deck tile Wardroom messroom ------------------------------------------ Wardroom washroom and water closets -------------------------Ceramic tile Watch station mats Watch stations ------------------------------------------------- Notes: 1. This includes such traffic areas as routes used for topside passage from and between doors, ladders, those around important topside equipment, and those areas of other slip-resistant deck covering. In general, it should cover at least one complete circle of each deck house. The topside passage should be defined by a path approximately 36 inches wide. 2. For vessels on which rugs are not specified, install deck tile. 3. Rugs shall cover approximately three quarters of the total lounge area. For proper installation of the tile, the following 64. Materials and Installation-Surface materials should be used. Preparation (1) Slip-resistant ceramic tile. Slip-resist In preparing decks for the application of ant ceramic tile is unglazed porcelainceramic tile, resilient roll and tile deck coverceramic tile. The tile used for repairsing, and rubber terrazzo, all rust, loose scale, should conform to the specificationsand dirt should be removed by sandblasting or from which the original was installed. wire brushing. When neotex is to be applied, only wire brushing should be employed. Grease (2) Ceramic tile adhesive. Ceramic tile and oil should be removed with solvents and adhesive should be either latex mastic clean rags. Before any deck covering is inunderlay type or solvent type. stalled, all attachments to and penetrations of (a) Latex mastic underlay type. This the structure to be covered should be comadhesive requires no ventilation or pleted. When installing resilient deck coverings, fire hazard precautions during init is,Jmportant that the undersurface be level staUation but does require protecand·~as smooth as possible. Welds and high tion from freezing because it is the spots will readily show through resilient deck rubber emulsion type. covering, such as vinyl tiles and linoleum, un(b) Solvent type. This adhesive will notless properly faired. In such cases, weld seams freeze but for easier spreading andand high spots in excess of Yt 6 inch should be faster setting, should be stored atground down to extend no more than Yt 6 inch 70°. (21.1o C.) for at least 24 hoursand faired with underlay, if possible. Dished before use. areas in deck plate should be filled with under (3) Adhesive trowel. A special adhesive lay. trowel (fig. 62), as recommended by the adhesive manufacturer, is the 65. Ceramic Tile main tool used in the installation of a. General. Ceramic tile in shower stalls and ceramic tile. within coamings should be sl-oped toward the b. Installatio'Yir-Steel Decks. drain through the use of underlay. Minimum thickness of this underlay should be 1/4 inch. (1) For the installation of ceramic tile, AGO 6244A 66 Figure 62. Special adhesive trowel. when solvent-type adhesive is used, the following steps should be performed: Warning. No open flame, welding, cutting, or smoking should be permitted in spaces being covered. Minimum ventilation should be 250 cfm per gallon of adhesive applied per hour. (a) Permit the underlay to dry for a minimum of 2 days. (b) Cut tile with tile setter's cutters or by scoring with a glass cutter and breaking with pliers. Note. Tools should be kept clean with mineral spirits. (c) Cement trim tile to boundaries of deck and fit tile sheets to deck before applying adhesive. (d) Spread adhesive, using a sawtoothed trowel such as shown in figure 62, over as much area as can be covered in 10 minutes. Note. The adhesive should be applied in accordance with the adhesive manufacturer's .instructions. (e) Lay tile sheet within 10 minutes after spreading adhesive and beat gently with a rubber-padded block to insure contact with adhesive. (f) Remove paper from face of tile by wetting with a sponge after adhesive has its initial set and before it is dry. (g) Realine tile if necessary. (h) Use kneeling boards to prevent movement of tile. ( i) Remove adhesive from surface of tile by cleaning with mineral spirits or razor blade. (2) For the installation of ceramic tile, when latex mastic underlay-type adhesive is used, the following steps should be performed: Note. This adhesive contains a water base and requires no fire and ventilation precautions. However, precautions against freezing must be taken during installation and for at least 24 hours after installation. (a) Underlay base should be permitted to dry 24 hours before application of tile. (b) Cement trim tile to boundaries of deck with latex underlay adhesive. Note. The pot life of the adhesive can be considerably increased by covering the can with damp burlap when not in use. (c) Fit deck tile before application of adhesive. (d) Spread adhesive using a sawtoothed trowel. Note. Because this adhesive has an open time of approximately 20 minutes, it must not be spread too far ahead of tile applica tion. (e) Press tile gently with a rubberpadded block to insure adhesive contact. (f) Allow to dry for 24 hours, the remove protective paper from face of tile by wetting with a sponge. (g) Use kneeling boards to prevent movement of the tile. (3) When grouting the tile, the following procedure should be used: Note. The tile should be covered with a heavy building paper for at least 3 days to protect the grout. Areas subjected to water flooding, such as shower stalls, should be allowed to dry thoroughly before use. Grout ing should not proceed until the tile is firmly bonded. (a) Moisten joints with wet sponge and grout with underlay grout, Military Specification MIL-D-3135. (b) Work grout mix into tile joints with a flat steel trowel. (c) Remove all excess grout by drawing a squeegee diagonally across tile joints. (d) Clean off surface film after 30 minutes by using moistened, finescreened sand and rubbing diagonally across joint with a burlap cloth. AGO 5244A Note. If the grout pulls out during this procedure, allow a few more minutes for drying time. c. Installatior~r-Wood Decks. (1) For smooth and level decks which have no spring, the following procedure should be used when installing ceramic tile: (a) Install a two-ply, unpigmented, polyester glass deck covering of Celastic as a waterprofing base. The tile should be flashed 4 inches along the bulkhead. (b) Roughen the surface lighly when this covering is dry and apply ceramic tile as outlined in b (1) and (2) above without underlay. Note. Underlay can be used in shower stalls for sloping toward drains. (2) On decks that are springy, install a %-inch-thick marine fir-plywood base, then proceed as above with the installation of two-ply polyester glass deck covering of Celastic. d. Installation Over Existing Rubber Terrazzo and Other Mastic Deck Coverings. Where weight and movement compensation is not a prime factor, ceramic tile can be installed over intact and well adhered rubber terrazzo or other mastic deck covering. Install as follows: (1)Clean surface thoroughly with paint solvent or detergent to remove dirt and grease. (2) Bring to a plane surface with underlay when surface requires leveling. (3) Allow underlay to dry hard and proceed with installation as outlined in b(1) and (2) above. e. Repair. If loosening of the tile occurs, the loose tile should be removed and backs scraped free of dried adhesive. If the underlay requires repair, apply as outlined in b(1) and (2) above and allow to dry overnight. Spread adhesive on back of tile and adhere to the deck. Grout as described in b(3) above. 66. Concrete and Aluminum Diamond Plating Concrete should consist of a mixture of portland cement and lightweight aggregate, either vermiculite or pumice, and should have a minimum 28-day strength of 1,000 psi. It should be installed 2 inches thick. The aluminum diamond plating over concrete should be %6 inch thick, Military Specification MIL-F-17132, pattern A or B. The underside of the aluminum plating will be painted with one coat of wash primer and two coats of zinc-chromate primer, just prior to placing it over the concrete. Such decks are most commonly used in the living quarters of the vessel. a. Concrete. The metal deck must be thoroughly cleaned before applying a concrete covering. Sandblasting or wire brushes should be used, followed by a solvent wash to remove grease and other residue. The mortar consists of two parts of sand and one part of cement. Butt straps are often welded to the deck at 18-inch centers (fig. 63). Another mode of attachment is stretching galvanized wire at a distance of one half the floor thickness from the deck. The wire is passed through holes in pieces of flat iron to that deck. To prevent corrosion to the deck, a coat of zinc-chromate primer should be applied, and a layer of bitumastic enamel in a hot condition, added. A thin layer of heated stone dust should be sprinkled onto the enamel. When this has cooled, the concrete floor is laid on it. b. Aluminum Diamond Plating. The concrete deck presents a slightly rough surface for living quarters, making cleaning very difficult. To overcome this disadvantage, an overlay of aluminum diamond plating, Military Specification MIL-F-17132, is added. This provides a smooth surface, easy to maintain and clean. The plating is strong enough to withstand the dents and impressions from chair legs and desk supports and prevents the concrete from chipping and allowing water seepage onto the steel deck. One method of securing the aluminum plating to the concrete is by using welders' pads. These pads are predrilled, tapped, and welded to the steel deck before the concrete is laid. The metal screws are countersunk, thus presenting a flush surface upon installation. 67. Magnesite (Magnesium Oxychloride) a. General. Magnesite, Military Specification MIL-D-16680, is a troweled type of deck covering cement in a terra cotta color, and is 68 AGO li2UA Figure 63. Concrete floor with butt straps. normally used in areas receiving heavy traffic. This covering protects the deck and facilitates cleaning. To reduce the weight of the installation, the normally required thickness of 3fs inch should be closely observed. In inaccessible locations, the decking can be shaped to prevent accumulation of water. When mixing the covering solution, the specific manufacturer's recommended procedure should be used. The covering cement is applied with a trowel and care should be taken to insure that it is worked onto the metal reinforcement or latex underlay. Caution: Magnesite is corrosive to aluminum and must be separated from aluminum fittings on the deck by use of vinyl tape, rubber sheeting, latex mastics, or other applicable materials. Magnesite must not be used on aluminum decks. b. Preparation of the Steel Deck. The deck should be cleaned to bright steel by sandblasting, wire brushing, or similar methods, and washed with solvent to remove grease and other residue. An expanded metal lath should be welded to the deck at 18-inch centers. The metal reinforcement should be lifted slightly above the deck to provide a keying action. After insuring that the deck is thoroughly dry, a surface wetting coat should be brushed onto the deck and lath, taking care to cover all exposed surfaces. This coating generally should be allowed to dry overnight before application of the magnesite. In lieu of the metal lath, approximately one eighth inch of latex underlay can be used as the underlay for magnesite. Allow latex underlay to dry hard before application of magnesite. c. Repairs. When the deck covering has cracked and repair is necessary, the following procedures should be used: Note. When it is essential to increase the thickness of the covering to provide a fair surface over lapped plating and rivets, the decking itself should be built up to the normal required %-inch thickness. (1) Widen crack in the form of an inverted V with wide space at bottom. (2) Clean out dirt and grease. (3) Apply cement to surface. Note. If any excess cement is on the surface, it should be wiped off within 10 to 15 minutes so that it will not become gummy. The purpose of this dressing is to penetrate and seal the pores. (4) Use steel wool and treat with a sealer after the deck has been allowed to dry overnight. d. Cleaning. Cleaning of a magnesite surface should be accomplished with detergent solution. When necessary, the surface should be scrubbed with a stiff-bristled tampico brush or circular brush scrubbing machine, or mopped with a damp mop, using a synthetic detergent cleaning solution. After a period of time, the color of the decking can fade. Paint should never be used to furnish this deck covering. After using fine steel wool on the surface, the color can be renewed by treating with colorless dressing. 68. Polyester Resin and Celastic Coverings Polyester resin and glass cloth coverings and Celastic impregnated fabric, when used to cover decks, can prevent all but very minor leaks. In addition to preventing leaks, the coverings provide durable surfaces which need little maintenance. a. Polyester Resin. Polyester resin is combined with glass cloth to provide deck covering. It is supplied as a clear syrup-like liquid. An accelerator and a catalyst must be added to the resin in order for the resin to cure or harden. Warning: When using resins, accelerators, catalysts, and flammable solvents, all precautions and safety measures pertaining to flammable materials, such as no smoking, welding, or burning in the immediate areas, should be enforced. The use of rubber gloves during the application of resin and glass cloth is recommended. (1) Surface preparation. Prepare surface in the following manner: (a) Clear deck of any abrasive deck treads on sheet metal. (b) Remove deck installations which indicate leaking where removal is practicable. (c) Sand deck with an open-grit coarsedisc sander. (d) Remove all paint, leaving wood surface dry and absolutely clean. (e) Remove oil and grease spots by scrubbing with a strong detergent in hot water, followed by rinsing in fresh water. (f) Fill all holes, dents, gouges, and wide cracks with a wood filler that sets to a hard surface. Duratite or similar plastic compounds are satisfactory, but oil base putties must not be used. (g) Allow calking or filler compound which is hard and in good condition to remain, but if loose, remove .and replace with new filler. (h) Allow filler to dry, then sand down flush with surface. ( i) Insure that surface of wood is dry before applying coating. Surface moisture should be less than 15 percent. (2) Application of polyester resin and glass cloth. There are two methods of ap plying polyester resin and glass cloth, as described below: Note. In shower stalls, the covering should be applied directly to the structure to avoid dead-air spaces. (a) The first method is as follows: 1. Apply a brush or rolled coat of resin to prepared wood. 2. Spread glass cloth smoothly over primed area and add another coat of resin. 3. Sand lightly after this coat cures, add a third coat of resin, and apply another layer of glass cloth. 4. Apply subsequent coats of resin as needed, with a minimum drying time of 16 hours between coats. 5. Insure that the resin, above the top layer of glass cloth except under ceramic tile, is pigmented: interior decks-green; shower stalls-light green. 6. Insure that covering is flashed upon interior bulkheads to an approximate height of 6 inches. (b) The second method of application is called the shingle method. Two layers of glass cloth are applied without waiting for the resin to cure; thus, sanding between coats is avoided. The procedure is as follows: 1. Lay covering with seams of cloth parallel to centerline. 2. Apply a heavy coat of catalyzed resin with a brush or roller to prepared area for first strip of glass cloth, half width. 3. Apply a strip of half-width glass cloth immediately and squeegee it down. Note. Some. resin will come through in smoothing the cloth. 4. Coat area of next strip with resin. 5. Apply second layer of full-width glass cloth, covering preceding glass cloth and extending onto prepared deck. 6. Apply subsequent strips of fullwidth glass cloth and resin as needed, with each piece halfway overlapping the piece ahead. 7. Work out all air bubbles by using a squeegee to completely impregnate glass cloth with resin. Note. At deck edges, the cloth is run down 2 inches over the edge. Glass cloth should be butted, not lapped, to the deck house and deck installations that were not removed. (c) After 16 hours, when the deck covering cures, it is lightly sanded. The deck fittings and installations that were removed are reinstalled and bedded in double planking cement, Military Specification MIL-S-19653. Double planking cement is also applied to the waterproof seams of butted edges along the deck house and fittings that were not removed. An additional coat of resin is then applied. For a nonskid surface, foundry sand having a screen size of about 50 mesh is sprinkled on the walkways while the pigmented resin coat is wet. When the resin cures, excess sand is then swept away. A final coat of pigmented resin can be applied to improve the appearance of the deck. As an alternative, abrasive deck tread, Military Specification MIL-D-17951, can be installed in walkways for a nonskid surface. (3) Repairs. Damaged sections in the reinforced plastic covering can be repaired by patching. The repair process involves the preparation of the damaged section by cutting away loose or jagged areas, sanding, and applying a patch of glass cloth and resin. Repair kits with instructions for use are available from stock. b. Celastic. Celastic is the trade name of a proprietary coating material composed of a fabric impregnated with a thermo-plastic resin and activated by soaking in an organic solvent. Note. The quantity of Celastic required for covering a deck is based upon the area, allowing an additional 5 percent for laps, flashings, and repairs. (1) Surface preparation. It is not necessary to remove existing covering if it is reasonably secure. Loose paint, AGO 5244A patches, and tacks should be removed, and excess tar or calking should be scraped off. The surface must be clean, dry, and even. All deep gouges should be filled with wood filler. A strip of about 3 inches around deck fittings and the area to be covered should be sanded to clean wood. All metal to be covered should be cleaned by sandblasting, coarse abrasive, or power grinder (not wire brushing), followed with a phosphoric-acid wash primer, and allowed to dry. Glossy paint surfaces and smooth, bare wood should be rough sanded. (2) Preparation of Celastic and activator. Before immersing the Celastic in activator solvent, the selvage, 1,4 inch on both sides of the roll, must be torn off and horizontal seams cut out This type material will tear straight, lengthwise on the roll. Make a small cut at the desired width and tear.· Cut it crosswise, as a half width (2 feet) is easier to handle than a full width. Celastic can be readily fitted around all deck installations. In some cases, it can be quicker to remove small fittings and replace them when the Celastic installation is completed. Celastic fabric is fitted to a dry deck. On wood planking, it should always be laid lengthwise across the planking. When deck house coaming is wood, Celastic should be extended as high as necessary to form flashing. Flashing can be a separate, wide strip and should be installed first. Where coaming is of metal, adhesion of covering will not be as effective as to wood coaming, so the material cannot be relied upon to provide a seal, Celastic should be butted to metal installations and sealed with double planking sealing compound, Military Specification MIL-S-19653. Where separate strips of flashing are installed, Celastic should be butted to the deck house. Warning: Activator solvent is a ketone material which is highly ftam mabie. All precautions and safety measures pertaining to flammable solvents should be enforced. Celastic solvent can have an irritating effect on the eyes. Care sho.uld be taken to protect the face from contact with the solvent. (3) Installation of Celastic and activator. (a) Insure that dip tank is covered when not in use to cut down on evaporation of activator solvent. (b) Run measured flashing strips of Celastic through dip tank for 30 seconds, then roll them up. (c) Press each strip firmly along deck house corners and smooth in place. (d) Fit several pieces of Celastic, starting at forward end of deck. (e) Chalk area off to properly aline it. (f) Fit each piece to lap corner angle and extend down sides for about 1 inch. (g) Roll piece on a pipe and place it in dip tank so that it rests in V cut. (h) Pull material through tank for about 30 seconds under a roller weight pipe. ( i) Roll piece onto a carrying pipe and carry it to area to be covered. (j) Unroll Celastic on surface slowly, but steadily. (k) Push or pull lengthwise with roller coater to force any trapped air from under roll. ( l) Press Celastic firmly to surface, paying special. attention to edges and seams. Push roller over Celastic several times. (m) Use same method in applying each piece, making sure to have a 1!2· inch overlap. ( n) Install only one layer of Celastic. Note. To obtain a nonskid surface, sand should be sprinkled over the Celastic. Activator can be used to redampen surface. As an alternative, nonskid fabric or slipresistant deck covering compound, Military Specification MIL-D-23003, can be applied after Celastic hardens (about 24 hours). (4) Repairs. If air is trapped during installation, do not try to release it until the entire piece has been laid and then make a small puncture and work air out with fingers. Soak puncture with activator solvent BBX and rub it until it is sealed. If the surface is damaged, cut out the damaged area in the shape of a rectangle. Cut a piece of Celastic to conform to this area. Soak in activator and apply to daJllaged area. Press down firmly and apply a small amount of activator solvent BBX Type N along edges. Rub until edges are sealed. 69. Resilient Roll and Tile Deck CoveringsGeneral Marbled, fire retarding, vinyl asbestos tile, Military Specification MIL-T-18830, 0.080 inch thick, is the standard resilient deck tile covering approved for steel surface vessels. Fire-retarding linoleum tile is also an approved deck tile covering but is being superseded by vinyl asbestos. Vinyl asbestos is linoleum tile in two solid colors, green and terra cotta. Battleship linoleum, 1Js inch thick, is normally approved for wood vessels. a. Installation. (1) All deck coverings and adhesives should be kept at a temperature of 70°F. (21.1 °C.) for at least 24 hours prior to installation. (2) The area being covered should be kept at a temperature of 70°F. (21.1°C.) prior to, during, and 24 hours after the installation. (3) After laying, the deck covering should be rolled and weighted to provide permanent adhesion. ( 4) A bending sealer should be used to waterproof all seams against bulkheads, stationary furniture, pipes, and other deck fittings. ( 5) Where weld lines prevent deck covering from butting tightly against structure, calking compound, Military Specification MIL-C-18969, should be used in lieu of cement and painted to match the deck tile after the calking compound skins over. ( 6) The weld line against bulkheads AGO 6244A should be faired with underlay and the tile butted against the bulkhead. (7) If desired, the tile can be squared off in way of stiffeners. b. Application of Vinyl Asbestos Tile. (1) Maintain the tiles at a minimum temperature of 70°F. (21.1 °C.) for 24 hours. Note. At temperatures below 70°F. (21.1 o C.), the material is not flexible enough for satisfactory installation. (2) Insure straight seams by squaring off the area to be covered. If practicable, start the installation of tile at the center of the space and work to the edges so that an even balance of tile around the edges of the space results. Note. If a pattern of two or more colors is desired, lay out the pattern on graph paper; each square of the paper can be considered as one tile. For spaces with nonparallel opposite bulkheads, use a large square and chalk line at corners to square off the compartment into a rectangular or square layout. To locate the center of the space, strike a chalk line from the midpoints of opposite bulkheads after squaring off. (3) Start installation at sections of space where work can proceed to completion without kneeling on freshly laid tile. ( 4) Spread cement with a fine-toothed trowel, approximately 1 square yard at a time, at a coverage of 100 square feet per gallon. Note. Excess cement will reduce adhesion. ( 5) Force tiles into tight contact with each other while cement is wet. Flex each tile downward, slightly saucerlike, so that the four corners hit the deck first. (6) Cut half tiles by scoring and cutting through with a sharp knife. Note. A dull or unpointed linoleum knife should not be used for cutting the tiles, as this will result in uneven edges. (7) Clean any cement off the surface of tiles with a damp rag when wet, or with paint thinner when dry. (8) Roll deck covering to insure complete contact with deck. If any high joints remain, rub tiles even and smooth with the head of a hammer. AGO 6244A (9) Make installations bulkhead-to-bulkhead or squared with stiffeners. If an exposed edge is not butting a fitting or bulkhead, attach a stainless steel or brass strip, 1 inch by 0.080 inch, to deck to protect edge. A vinyl asbestos, beveled edging strip cemented to deck with rubber latex cement also can be used. Caution: As little traffic as possible should be allowed over the newly cemented areas until the in· stallation is completed and thoroughly rolled. Normal foot traffic can be placed on the deck almost immediately because no indentation will occur from this type traffic. However, heavy concentrated loads, such as legs of heavy furniture, must must not be placed on the floor until the cement has completely set (approximately 2 weeks). c. Repair. If a tile requires replacement, remove by forcing a wideblade paint scraper under it. Chip out cement to bare steel, clean spot with paint thinner, and apply tile as outlined in b above. 70. Rubber Mastic (latex Mastic) Coverings -General Master deck coverings are installed over the entire deck except where built-in equipment interferes. They are used to protect the deck and to facilitate cleaning and maintenance. In the vicinity of drains, in shower stalls, with coamings, and in inaccessible areas, they should be sloped toward the drain. Underlay can be used to assist drainages. Components from a single manufacturer should be used in the same compartments to avoid differences in color and to assure compatibility. a. Neotex. Caution: Never add water to any materials listed below. Do not vary the mixing proportions of any of the materials mentioned below. (1) Mixing-surface wetting wax. (a) Pour 1 gallon of paste into clean 5gallon pail. (b) Add exactly one-half bag, or 18 pounds, of grout powder. 73 (c) Blend these materials thoroughly by stirring with a paddle until mixture is completely homogenized and free of lumps. Note. This material is enough to cover 100 square feet and will remain workable for about 1 hour. Fresh water will clean tools if they are washed immediately after use. The body coat should be mixed immediately after the surface wetting wax. (2) Mixing-body coat. (a) Pour 1 gallon of paste into mixing trough. (b) Add one bag of aggregate. (c) Blend these materials by turning them over with a hoe. Note. The body coat will become a homogeneous mass, free of lumps and dry material. The above quantity is enough to cover 25 square feet in a 14-inch thickness and will remain workable for about 1 hour. (3) Application. Caution: Neotex should not be applied when the temperature is below freezing. Application is also difficult if the temperature of the deck is above 75°F. (23.9°C.), as the material will tend to dry too rapidly. If the paste becomes frozen, allow it to thaw out slowly at room temperature. Do not heat to speed up the rate of thaw. Do not store the paste near a heater or in any area where it might become heated above 90°F. (32.2°C.). Do not apply on a hot subsurface. (a) Pour a small amount of the surface wetting wax onto deck and, using a paint brush, paint an area of about 8 square feet with a thin uniform coating. (b) Apply body coat onto surface wetting wax while lather is still wet. Body coat should be applied in %inch thickness. (c) Place material by edge troweling. Hold trowel at 45° angle in direction of motion of trowel. (d) Smooth material immediately after application over a few feet by lightly troweling with trowel held almost flat. Note. Care should be taken that this smoothing operation is done quickly and with a minimum of retroweling, as the quick setting of the material will not permit repeated trowelings. (4) Mixing-grout coat. (a) Pour 1 gallon of paste into clean 5gallon pail. (b) Add exactly one-half bag, or 18 pounds, of grout powder. (c) Blend these materials thoroughly by stirring with a paddle until mixture is completely homogenized and free of lumps. Note. This blend is enough to cover 160 square feet in one coat and will remain workable for about one hour. (5) Grouting. (a) Allow body coat to dry for 24 hours and then sand off all trowel marks with a sanding block, using medium-grit sandpaper. (b) Sweep surface free of any dust with a soft broom. Note. In the event that oil or dirt has spilled on the surface, it should be washed with a minimum amount of fresh water. (c) Apply two .coats of grout to smooth off body coat. Pour a small quantity of grout onto surface and scrape. Then trowel grout over surface. Allow grout to dry at least 4 hours and apply additional coat. Note. The grout coat should just fill the pores of body coat and should not develop any thickness on top of the body coat. (d) Allow grout to dry 24 hours before sanding. After drying, sand off any trowel marks using fine-grit sandpaper. (6) SeaUng. The surface to be sealed should first be vacuumed or swept clean of any dirt and dust and be absolutely dry. The sealer should be stirred thoroughly and kept stirred during use. It should be applied in two coats. Each gallon of sealer will cover approximately 125 square feet in two coats. The sealer can be applied with a brush or paint roller and should be spread on liberally, not brushed in or rolled thin. Drying time for each coat AGO 5244A of sealer is approximately 6 hours. This sealer will leave a flat finish with a uniform color. Allow the deck covering to cure for 3 days before exposure to heavy traffic. Where the deck covering will be flooded with hot water, as in shower stalls, it is desirable not to expose it to use for 2 weeks. However, where conditions. prevent this long delay, do not expose deck covering in shower stalls to hot water for at least 3 days after final application of sealer. Caution: Do not wash the surface. Do not use lye or other strong alkali on this deck covering, as such application can be injurious to surface. Two tablespoons of detergent per gallon of warm fresh water can be used. Swab on cleaning solution and allow to remain on deck about 5 minutes. Scrub and mop up. Final mopping should be done with clean water. (7) Repairs. Occasional. resealing will be necessary to revitalize color. Reseal with sealer as outlined in ( 6) above. When the surface becomes rough or worn, it should be regrouted as outlined in ( 5) above. b. Felbatex. (1) Mixing-general. Note. Never add water to any of the mixes. (a) Make sure that there are five clean 5-gallon cans available for mixing the emulsion and the compo. (b) Wash cans with water several times during use to keep them clean, drying thoroughly each time. (c) Use mechanical mixer always to mix each can of emulsion and Felbatex readimix topcoat thoroughly before use. Note. Always keep one 5-gallon can of clean water for cleaning mechanical mixer. Place paddle of mixer in water after each use, and dry before reuse. (2) Mixing-prime coat. (a) Stir and pour 9 pounds of Felbatex emulsion into a clean 5-gallon pail. (b) Add one 45-pound bag of Felbatex AGO 5244A fine coat compo and mix thoroughly using mechanical mixer. (c) Add an additi ,# Q9 I SYMBOL KEY QUICK ACTING WATERTIGHT DOOR DECK DRAIN VALVE DECK DRAIN EDUCTOR (JET PUMP) FLOW IS IH DIRECTION OF FLARE OVERBOARD ·cOHHECTIOH FOR SUBMERSIBLE PUMP STOP CHECK VALVE STOP-LIFT CHECK VALVE RELIEF VALVE OR SPRING LOADED CHECK VALVE SWIVEL MONITOR HATCH MANHOLE QUICK ACTING SCUTTLE REMOTE CONTROL VALVE Figure 67. Damage control diagram symbols. AGO 6244A 93. Knowledge Necessary for Damage Control Effective damage control requires assigned personnel to have a detailed knowledge of vessel construction, characteristics, compartmental configurations, and stability. Also of major importance is knowledge of the equipment placed aboard to prevent or control damage. Basically, the control of damage depends upon the ability of personnel to take prompt, corrective action, using available materials. Damage control duties include knowledge and use of blueprints of the vessel and appropriate damage control diagrams. Because a vessel is a very complex structure, it is difficult for an individual to learn all the details of various piping systems and damage control fittings built into the vessel. There must be some other means of locating a section of the vessel or a part or section of an individual system. The best way to accomplish this, particularly during an emergency, is with diagrams of the vessel. In order to read a damage control diagram correctly, personnel assigned to damage control duties must learn to recognize the standard symbols used in diagramming the various systems. On most damage control diagrams, lettering and numbers indicate the different compartments, their use, and the different systems with their component parts. Some of the symbols used on damage control diagrams are shown in figure 67. The symbols are important to the correct reading of the diagram and are usually color coded to simplify identification. 94. Objectives of Damage Control The three basic objectives of shipboard damage control are as follows: a. P'revention. Take all practical preliminary measures before damage occurs by insuring the maintenance of watertight and fumetight integrity, maintaining reserve buoyancy and stability, removing or eliminating fire hazards, maintaining and distributing emergency equipment, and training of personnel. b. Control of Damage. Minimize and localize damage, when it does occur, by such measures as control of flooding, preserving of stability and buoyancy, firefighting, and first aid treatment of personnel. AGO 5244A c. Repair. Accomplish emergency repairs or restorations as quickly as possible after damage occurs, by such measures as supplying emergency power, regaining a safe margin of stability and buoyancy, replacing essential structure, and moving and placing essential support equipment. 95. Types of Damage Knowing the type of damage and what emergency repair action to take can save the vessel and permit it to continue on the assigned mission or give it the capability to return to a base for more extensive repairs. Generally, most damage can be classified as follows: a. Large holes in the underwater hull. b. Small holes and cracks in the underwater hull. c. Holes in the hull above the waterline. d. Punctured, weakened, or distorted bulkheads. e. Flooded machinery compartments or other vital spaces. f. Warped or sprung doors and hatches. g. Weakened or ruptured beams, supports, and other strength members. h. Ruptured or weakened decks. i. Wreckage interfering with system function. j. Ruptured or cracked pipe lines. k. Severed or damaged electric cables. l. Broken or distorted foundations under machinery. m. Broken or pierced machinery units. n. Fire with its attendant heat, smoke, and other damage. 96. Effects of Damage-General The nature of repairs that a vessel requires depends upon the type of damage, type of vessel and location of damage. Collisions, grounding, and storms have in many cases caused damage so severe as to threaten the survival of the larger vessels. Self-inflicted damage can stem from the lack of adequate preparation or from general neglect. Other causes that will impair stability are deck icing in cold weather, excessive deck load, overloading any area in general, removal of ballast, and free surface in tanks or bilges. 97. Underwater Damage to Floating Craft and Amphibians Underwater damage to small vessels is classified generally as combat damage, collision damage by contact with another vessel, or collision damage caused by underwater obstacles, floating or fixed. a. Combat damage, for the purpose of this manual, means small gunfire, shellfire, nearmiss bombs, and small mines. It is assumed that large bombs, shells, and mines will totally destroy the vessel. b. Underwater damage to a hull as a result of collision or grounding might not cause a vessel to immediately sink or require abandonment but the following can occur: (1) List. (2) Flooding with sea water and fuel oil. (3) Impairment of vital operating systems in damaged area. ( 4) Possible fire. ( 5) Possible shock effect on instruments and gages. c. The list of the vessel can be presumed to be due to off-center weight. If the vessel is under way when damaged and the probability of receiving further underwater damage is possible, prompt removal of list is the prime consideration. List has many undesirable effects, some of which are the following: (1) Impaired speed due to increased propulsion resistance, increased difficulty in operating the main propulsion plant, and possible improper immersion of screws. (2) Impaired maneuverability. (3) Impaired overall stability due to list and improper trim. ( 4) Increased difficulty in servicing and operating deck equipment. d. A combat hit which strikes the vessel's side just below the waterline can cause all the effects outlined above and, in addition, is very apt to tear the sheer strake and the main and second deck entirely across the vessel, with serious decrease in hull strength. A combat hit near the bow can blow off the entire bow section, usually at a heavy transverse bulkhead. A secondary gasoline or ammunition explosion can cause the same damage. A hit near the stern will probably carry away one or all of the screws and can render inoperative or destroy the rudder and steering gear. e. Solid flooding below the waterline, although it reduces reverse buoyan~y, will have a beneficial effect on stability if there is no list and sufficient freeboard exists. Generally, a compartment must be vented in order to flood solidly. Venting can take place through a regularly fitted air escape, through an open hatch or scuttle, through a ventilation fitting, or by way of holes and sprung joints in boundaries. If air cannot escape and the flooding hole is fairly low (or if flooding is from an internal source), the rising water traps a bubble of air above it, which will compress until the pressure of the air internally is equal to the external hydrostatic head or pressure. In the case of a broken fire main, the pressure available to force water into the compartment is usually 100 pounds or more. If the entrapped air cannot escape, a point will be reached where its pressure can exceed the strength of the retaining structure. Keep air escapes clear. f. When a vessel sustains underwater damage, normally a violent shock will break or derange delicate equipment such as radio and radar equipment~· Sometimes antennas shake loose and fall to the deck. Brittle materials such as cast-iron valve bodies or cast-iron base plates under machinery can be fractured even at considerable distances from the damaged area. The shock frequently opens circuit breakers. Violent heaving of decks causes personnel injuries, particularly to those who are standing. Personnel should be instructed to lie down and cushion their heads with their arms when underwater attack or collision is imminent. g. A flash of flame from incandescent gases created by an explosion, unless it is damped by liquids, spreads through the affected area. Hot fragments can also start fires in remote areas. Acrid smoke and toxic gases from an explosion and fires can necessitate the use of oxygen breathing apparatus of air-line hose masks. h. It is inevitable that some wiring circuits will be severed by blasts and fragments. AGO 6244A Severed and grounded cables will interrupt power in the immediate vicinity and can short the entire electrical system. i. The powerplant can be affected with the possibility that all propulsion will be lost. If damaged area is amidships, machinery compartments can flood. j. Overall whip or flexural vibrations can cause buckling or failure of the hull girder. The location of such failures can be remote from the damaged area and will depend upon such factors as the size, position and type of damage, its distance from the hull, the type of vessel, and how the vessel is loaded. A small slender vessel hit .at one end can suffer a compression failure of the hull girder anywhere in the midship region. 98. Corrective Measures for Control of Damage Corrective measures for control of damage consist of immediate local measures and overall ship survival measures. a. Immediate Local Measures. Immediate local measures include all actions taken by repair personnel at the scene of the damage to extinguish fires, halt flooding, and make emergency repairs. to the operating systems of the vessel. Immediate local measures do not necessarily require a decision from the damage control officer. Repair personnel should be trained to perform emergency repair automatically and with efficient speed. The damage control officer should be notified of the damaged areas and be continuously informed of the progress of repairs. Repair personnel will normally perform the following: ( 1) Establish primary flooding boundaries by selecting a line of bulkheads and decks remaining intact, and plugging, patching, and shoring as necessary to obtain a watertightarea. (2) Locate, control, and extinguish fires. (3) Establish a secondary flooding boundary should the primary boundary fail. ( 4) Decrease the flooding boundaries and move the boundaries toward the primary damage by plugging, patching, and shoring. (5) Isolate damage to piping and electrical systems. (6) Restore service to piping systems with patches, jumpers, clamps, couplings, and other emergency repair methods. (7) Rig emergency power and communi~ cations. (8) Rescue and give first aid to wounded personnel. ( 9) Remove wreckage, loose debris, oil, and fuel. (10) Cover, barricade, and mark dangerous areas. (11) Ventilate smoke or toxic gas-filled compartments. b. Overall Ship Survival Measures. Overall ship survival measures are those actions determined by the engineering officer and originated from the damage control officer for the proper handling of list, trim, buoyancy, stability, and hull strength. This includes one or more of the following five basic objectives: (1) Improve overall stability. (2) Correct for off-center weight. (3) Restore reserve buoyancy. ( 4) Remove or improve trim. (5) Relieve stress on damaged hull girder. Caution: These objectives affect the operation of the ship as a whole, and their accomplishment takes time. Actions taken to properly perform these objectives involve weight removals, weight additions, weight shifts, and restoration of boundaries. Taking actions to correct one of the deficiencies without considering the others can have serious effects on one or more of the remaining four. Such secondary effects can possibly be undesirable. The decision in selecting the proper objective should mean the difference between saving or losing the vessel. 99. Protective Equipment In the planning and preparation of damage control functions, the availability of protective clothing and equipment should not be overlooked. Heavy leather boots will protect the feet and legs of men working around wreckage. Leather gloves, of a gauntlet type, will protect hands and wrists. Asbestos gloves and boots AGO 6244A will protect hands and feet from heat. Electrical repairmen should be protected by insulated gloves, boots, mats, and tools. If insulated tools are not issued, tools can be insulated by wrapping them with rubber tape or rubber tubing. 100. Immediate Procedures After Compression Failures A vessel that has suffered compression failures amidships is in just as dangerous a condition as if the main strength members had been carried away. The immediate action that should be taken in such a case is as follows: a. Reduce speed immediately. b. Change course to minimize hogging, sagging, and pitching. c. Make an immediate, careful inspection of the damage. Check midship region for evidence of wrinkled shell or deck plating, buckled or failed longitudinals, and buckling of stanchions or bulkheads which brace the hull girder. Look for hidden damage under machinery or behind cargo or stores. Use shallow diving equipment should there be any flooding amidships. Examine fuel and oil tanks for evidence of contamination and leakage. d. Proceed immediately for the nearest safe anchorage if the tactical situation permits. e. Commence repairs en route if at all possible. f. (;onsider beaching the vessel if damage is severe or if heavy weather is imminent. 101. Procedure After Reaching Anchorage Once a safe anchorage has been reached, a thorough inspection of all damage must be made and temporary repairs completed before attempting a voyage in the open sea to a shipyard, floating dry dock, or repair base. Temporary repairs can be made with any suitable material available, if necessary removing it from less critical parts of the vessel. To restore required strength to the damaged vessel, perform the following: a. Replace wrinkled shell plating and deck plating. b. Replace buckled or broken longitudinal members with long beams of greater crossseCtional strength than the original. c. List vessel in order to weld below waterline if necessary. Longitudinal beams will be more effective when welded across the failure on the outside of the hull. d. Pay particular attention to repair of longitudinal and deck girders and all strake members of the hull. e. Shore up buckled stanchions and transverse bulkheads to restore vertical strength. 102. Flooding and Sinking The term flooding water refers to water which has entered the vessel as a result of damage. Flooding can occur from a number of different causes such as underwater or waterline damage, ruptured water piping, the presence of excess water from firefighting or counterflooding, and the improper maintenance of boundaries. a. Preparatory Measures to Resist Flooding Before Damage. One of the most important predamage actions to resist flooding is the preparation of a systematic set of procedures outlining specific actions to be taken by crewmembers. This action includes the detailed training of crewmembers to insure automatic performance in the event of an emergency. b. Learning the Design Resistance of Vessels. An important initial step for all crewmembers is to learn the features that have been designed into their specific craft to enable it to resist flooding. The most significant of these features is the extent and type of subdivision. The subdivision of the vessel willdetermine the extent and type of flooding that can occur and the corrective measures needed after damage. Damage control personnel should be familiar with the level to which bulkheads adjacent to the damage can be submerged before uncontrollable, progressive flooding arises. After damage, there will be no time for making computations. Knowled~e of the possible effects of the various type of damage, using the flooding effect diagram, will provide for the use of good judgment in deciding what corrective measures are required when the time for a decision arrives. c. Learning the Means to Combat Flooding. Both speed and accuracy are required to combat flooding. To be effective in applying cor- AGO 6244A rective measures, damage control personnel must be familiar with the equipment provided to control list and trim and to improve stability. Detailed damage control procedures should be prepared for each particular vessel. These procedures should be made available to all concerned crewmembers for reference and familiarization. The damage control procedures should give instructions for operating the various systems and should include adjustment and repair of watertight enclosures. Special attention should be given to specific ·procedures such as drainage, jettisoning, fuel oil transfer, and flooding effect procedures. The following can be used as a guide for preparing damage control procedures: (1) Statement of purpose or object of the procedure. (2) Description of system or systems, including their important parts. (3) Method and procedure of operation to be followed for damage control purposes. ( 4) List, classification, and cognizance of fittings. ( 5) Simplified diagrams of most important systems and parts of the vessel. d. Drainage Plans and Procedures. Because the vessel's drainage systems provide means to suppress free surface and remove weight, it is sometimes best to give priority to eliminating loose water and high weight instead of low weight and solid flooding. Removal of flood water from one side of the vessel is beneficial in correcting off-center weight, but it can create undesirable effects on vessel's buoyancy and stability and symmetrical flooding. Effective drainage plans and procedures should contain details of the vessel's installed drainage systems. All water entering from leaks must be removed to prevent flooding. e. Jettison Plans and Procedures. Jettisoning procedures should establish a definite priority which begins with the more easily removed and less vital weights. The procedure should specify the approximate gain in stability from removing each of the weights involved in order to give responsible personnel some idea of the relative importance of each and the results to AGO 6U<&A be attained. This gain in stability can be predetermined on the basis of displacement and buoyancy for loading with sufficient accuracy. The consequent rigging problem is of large magnitude, often covering many hours of backbreaking work to restore seaworthiness to a crippled vessel. The speed in gaining some immediate effect will be enhanced by a plan of action which outlines responsibility for removals, organization of jettison teams, and preparation of tools and methods. f. Fuel Oil Transfer Plans and Procedures. Because it is possible to jeopardize a vessel through creating a transverse moment when it is not needed, a specific responsibility should be created in this procedure to govern the initiation of fuel and ballast transfer after serious damage. Such responsibility will also expedite the rapid transfer of oil or water if a transverse moment is required. Instructions should be included which provide for keeping installed sluice valves closed at all times, except when in actual use, to avoid extensive free-surface effect. For the same reason, pumping down or starting the pumping action into more than one tank at a time should be avoided. Common athwartship suction lines to tanks on opposite sides of the vessel should always be kept blocked by a closed valve to reduce free~surface effect and prevent liquid from running downhill if a list should develop after damage. This is the same effect as athwartship sluicing and usually is equally objectionable from the stability viewpoint. The fuel oil tank sequence procedure should outline detailed steps to be followed when emptying fuel tanks and also designate the order of ballasting. Commanding officers should not permit violation of these re quirements without considering the additional risk involving improper stability. g. Flooding Effect Plans and Procedures. (1) General. The preparation of this procedure normally consists of a tabulation of all the compartment numbers in the vessel with the value of freesurface effect entered opposite each number. Such tabulations can also indicate information on ·added-weight effect and free-communication effect. These calculations are of great value in predicting the possible flooding effect to be expected in a particular ves sel. These values are only recomd. Provision of adequate amounts of well mended guides and are not exact. distributed, operable, damage control equip Good judgment, based on an underment. standing of the principles involved, is 105. Strandings better than any number that can be computed. Some Army vessels are Amphibians and landing craft are specifically rarely provided with off-center voids. designed for beaching. Floating craft are someIf ballasting instructions are followed, times grounded, either by accident or by intenthere will be little occasion· for offtion. When the loss of stability or structural center flooding. However, such vessels damage threatens the vessel in deep water, the are susceptible to extensive free survessel can be deliberately beached to be reface and the accompanying possibility paired. In selecting a place to beach the vessel, of reduced stability. It is of value to preference should be given to a locality where calculate free-surface effects and enter the water shoals gradually and the bottom is these data on the liquid loading flat. Rock ledges or pinnacles, crosscurrents, diagram. and heavy surf should be avoided. A grounded (2) Supporting diagrams. Insure that vessel involves reflotation and retraction, hull flooding effect diagram and liquid inspection, and stability. loading diagram are available. The a. Refiotation and Retraction. When the ves flooding effeot diagram consists of a sel runs aground accidentally, the propellersseries of plans of the vessel at various should be reversed. If the vessel does not backlevels, showing all oiltight, watertight, away from the beach, no further use of theairtight, fumetight, and ftrefighting propellers should be made. The propellers besubdivisions. The liquid loading diacome less effective in shallow water, and pro.., gram consists of a series of plans peller wash can drive sand around the hull. of the vessel at various levels, as If the vessel does not back off using the propel necessary to show all tanks and voids ler, it should be weighted down by flooding allwhich are fitted for carrying liquids. tanks and, if necessary, flooding one or more hold compartments. Weighting the vessel down 103. Stability Training of Repair Parties is especially important if the tide is risingCrewmembers should be organized into reand a possibility exists of a heavy surf drivingpair teams and trained to take action autothe vessel harder aground or further damagingmatically to flooding; to plug, patch, and shore the hull. Ground tackle should be rigged and and to begin immediate removal of flooding suitable anchors laid seaward as soon as possiwater. Repair personnel should also be trained ble. If other vessels are in the area, they can in preparing and forwarding accurate reports be utilized to pull the grounded vessel free.concerning the nature of the flooding and the action being taken to combat it. All crewb. Hull Inspection. Once the grounded vessel has been weighted down, a careful inspection members assigned to a vessel should be trained of the hull should be made to determine thein general damage effects and recommended extent of damage. All voids should be sounded,corrective actions. fuel tanks checked for leakage, and interior of 104. Material Preparations the hull examined for signs of structural damThere are certain material preparations age. The exterior of the hull should be exwhich are vital to resist flooding. They include amined by using shallow water diving equipment. Soundings should be made all around the the following: vessel to determine the underwater slope anda. Maintaining the watertight integrity of condition of the bottom. In order to locate unthe vessel's subdivisions. derwater obstacles, smaller craft should be b. Proper classification of closures and used to continue these soundings in the direcfittings. tion toward which the grounded vessel is to be hauled. When the vessel is aground, the beach c. Proper adjustment of watertight closures. AGO 5244A exerts an upward force on the hull equal to that portion of the vessel's weight which is not supported by the buoyancy of the water. This upward force on the hull has an effect on stress which is the reverse of that force caused by flooding. If aground at one end, sagging stresses are increased; hence, weight additions should preferably be made at the ends of the vessel, while weight removals should be made from the midship region. If the vessel is aground amidships on a ledge or pinnacle, then hogging stresses are increased, and weight additions are better made amidships, while weight removals are preferable from the ends. Irregular rock or coral formations, or sharp changes of suction as at ledges, produce concentrated pressures that ofen crush hull plating and result in flooding. Such local damage is intensified if the vessel shifts its position. c. Stability. The magnitude of the ground pressure, or quantity of weight aground, is the reduction in displacement caused by beaching. This could also be stated as the difference between the displacement of the mean draft after grounding and the displacement when floating free. The ground pressure is applied at the point of contact and has all the effects on draft, list, trim, and stability of removing that many tons of weight from the location of the point of contact. If the point of contact is at the keel, it consists of low weight removal or transfer. If the point of contact is at one end, the vessel will trim by an amount equivalent to removing the quantity of weight aground from that end. If the point of contact is off center, the vessel will list to an angle corresponding to the offcenter weight removal. If the stability calculation is negative, the effect of this condition on list must be considered. The result can be capsizing if the vessel is aground only at the bow where it is narrow athwartships. If grounded throughout its length on a level surface, the vessel will not usually capsize even if high and dry. The greatest grounding force affecting stability will occur when the waterline of a vessel grounded at high tide drops to that of a low tide. As the tide drops, the buoyant force of water becomes less while the grounding force gets proportionally larger. To improve stability where it appears that capsizing is probable, corrective action should be taken to accomplish the following: AGO 5244A (1) Jettison topside weights. (2) Ballast. (3) Suppress free surface effect by having all equalizing valves on tanks secured. ( 4) Lower liquid or solid weights. (5) Restore watertight boundaries. Note. The use of these corrective measures should be based on the effect on hull strength and the ability to refloat the vessel. d. Considerations for Good Procedure. In most cases of stranding the following considerations will ordinarily constitute procedure: ( 1) Every possible effort should be made to refloat or retract the vessel, to prevent the vessel from broaching pounding, or working harder aground. (2) Anchors to seaward should be quickly laid if possible to prevent the vessel from working further ashore. ( 3) The vessel should be weighted down, not lightened, in an effort to help keep it from working harder on the beach and to prevent damage caused by working and pounding of the vessel on the bottom. e. Lightening Craft. After weighting the vessel down, it is necessary to lighten the vessel before reflotation or retraction is attempted. When the ground tackle is ready and the tide is satisfactory, the vessel can be safely lightened while a strain is being taken on all cables. Engines in the stranded vessel should be warmed up, but in no event should the propellers be turned over. This is to avoid filling the heat exchangers with mud and sand and to avoid damaging propellers on the bottom or fouling ground tackle lines. Shifting fuel, oil, and cargo or stores fore and aft can produce a change of trim that will aid in clearing the vessel. It can be necessary to unload some cargo or stores to further lighten the vessel. Rolling a small vessel will assist in breaking the suction created by the mud or sand. Jets from air or steam hoses are also useful for this purpose. f. Tidal Conditions as Aid. When a floating craft has grounded or a landing craft has difficulty retracting from the beach, use the tide as an aid to refloat or retract the craft. By minor weighting and lightening ·of the craft and waiting for the rising tide, reflotation or retraction can be simplified. 106. Prevention of Progressive Flooding required for such major repairs. Take what ever action is necessary to save the vessel. and Burning Many vessels have gone down, not as a direct c. Holes at Waterline. Holes in the hull at or result of the initial damage, but as a result of just above the waterline destroy reserve buoyprogressive flooding, fire, collapsing bulkheads, ancy. Should the vessel roll in a heavy sea or increased free surface, and human errors. Had lose buoyancy, these become submerged and flooding and fire boundaries been established admit water above the center of gravity which and the damage been confined to its original is extremely dangerous. This condition reduces area, many would still be afloat. All personnel stability, and as this water will present a large should do everything possible to prevent profree surface, the situation becomes doubly gressive flooding and burning. Hidden damage dangerous. These holes should be plugged at can cause the vessel to sink. Many hours are once, giving high priority to holes at the wateroften wasted trying to patch large or multiple line on the low side. If sheathing is near the holes in compartments which are already waterline, it has to be removed before holes can flooded or have large free surface areas. be plugged. Sheathing can be removed by cutSmaller holes through interior bulkheads causting the screws with a cold chisel and hammer, ing progressive flooding and more free surface, a pneumatic chisel, or simply by cutting the are often overlooked. In most cases, it would sheathing out with an axe. The best tool is a be better to plug those interior holes first in pneumatic shear, provided air pressure is availorder to localize flooding and preserve buoyable. A linoleum knife is effective on light ancy. aluminum sheathing. Another tool is a hook a. Types of Holes. Holes are frequently shaped knife about 18 inches long and fitted with a loop handle. several times as large as the object causing them. Elongated holes, sometimes a gouge of d. Jagged Protrusion. In almost every case, 6 to 8 feet long can be caused by combat-type heavy collision punches out part of the metal projectiles. Ricochets make the familiar keycompletely and bends the rest of it inward to hole. Splinters make weird patterns, from fuzzy form jagged protrusions. Plating can be circular holes burned through aluminum plating rumpled in the vicinity of the hole. Spidery to odd-shaped rectangles through steel plates. cracks or cuts can radiate from the holes. All Collision can cause similar types of damage. of these features complicate the job of making Cracks can result from stresses produced by effective repairs. These protruding edges of high seas. Holes of various sizes and shapes torn plating can be eliminated by pounding can be produced by blast effects or by shock. them with mauls or by cutting them away with Bulkheads can be split wide open or they can oxyacetylene torches. Either process takes time have small cracks or torn seams. Distortion of but the results are beneficial. Lightweight iron plating is common. Watertight doors and plates can be flattened by pounding, but heavier hatches can be bent away from their knife special-treatment steel plates must be cut with edges, especially if the fittings were not proptorches. erly secured. Rivets can be pulled through platCaution: Use welding torches with care toing. The welding around pipe lines passing prevent fires or explosions.through bulkheads can be cracked. Shafts pass e. Water Pressure. Water pressure causes ing through bulkheads can whip severely under some difficulties in making repairs to undershock, and not only will dislocate glands and water holes, but the difficulties of water prespacking, but also can rip adjacent bulkheads. sure are frequently overestimated. An underCracks in sea chests, ruptures in piping, and water hole only on one side is subjected to anholes left by careless workmen can also con. inward pressure of 0.444 psi for every foot oftribute to flooding. submerged depth. A hole 7 feet below the b. Large Holes in Underwater Hull. Complex waterline will be subjected to a pressure ofcollisions or explosions from contact mines or 3.1 psi. A circular hole 5 inches in diameternear-miss bombs can result in large holes in and 9 feet below the waterline will be subjectedthe underwater hull. Such damage cannot be repaired by the vessel's crew. A drydock is to a total pressure of 78% pounds. These pres 92 TENDING LINE Figu1·e fi8. Typical use of shallow-wate1· diving apparatus. sures are not excessive and are somewhat less if water is on both sides of the hole. f. Accessibility. The greater difficulty in repairing underwater holes is often accessibility. If the inboard compartment is flooded, it can be dangerous to attempt any repairs because opening a hatch or a door can permit flooding of another compartment. It can be necessary to enter a compartment with shallow-water diving apparatus to plug a hole (fig. 68). Work can be hampered by tangled wreckage which can be hidden by darkness or water. It is also difficult to submerge shoring and other buoyant repair materials. AGO 5244A g. Flooding Effect by Holes. The amount of water that will come into a vessel through a hole, or which will flow from one compartment to the next, varies directly with the area of hole and the square root of its depth. It makes no difference how the hole is made; if one side of the hole is submerged, water will flow through it in accordance with this formula. The entry of water can be reduced by listing the vessel to raise the level of the hole or by reducing the area of the hole. Listing the vessel is practicable if the listing action does not cause the cargo to shift and impair stability. Reducing the area of the hole is highly practic able in many cases, and its effect is very pronounced. h. Plugging Holes Promptly. Figure 69 shows the flooding effect of unplugged holes and of the same holes after inserting the most simple types of plugs. The volumes of flooding water are given in gallons and also in terms of the number of portable electric, submersible pumps required to handle the flooding. The pump capacities will be considerably less if the strainers are clogged with debris. It should be stressed that prompt plugging of holes is desirable to save vessel, to release pumps for use elsewhere, and to save wear and tear on those in use. 107. Restoring Watertight Integrity The following suggestions for plugging and patching holes will aid in the restoration of watertight integrity. They are temporary repairs to keep the vessel afloat. In most cases, they do not call for elaborate tools or equipment. They are principles which can be applied by using either prefabricated patches or suitable materials which are available and can be used to good effect. No temporary patch will be perfectly watertight, but if it can reduce the entrance of water by 50 percent, it can be possible to control flooding with the pumps. If a patch does not work, it could be the wrong type for the particular leak, or it could be employed improperly. A knowledge of plugs and patches and their use is mandatory to combat flooding and restore watertight integrity. a. Wooden Plugs. (1) Wooden plugs provide the most simple method of repairing small holes. Plugs made of soft wood are effective under THE AMOUNT OF WATER ENTERING A VESSEL THROUGH A HOLE VARIES DIRECTLY WITH THE AREA OF THE HOLE AND WITH THE SQUARE ROOT OF ITS DEPTH. PUMPS ARE THE NUMBER OF ELECTRIC SUBMERSIBLE PUMPS REQUIRED TO HANDLE THE FLOODING DEPTH IN FEET 1 2 3 4 5 6 7 8 9 DEPTH IN FEET 1 2 3 4 5 6 7 8 9 AVERAGE EFFECTIVE. FLOODING AREA SHOWN WITHIN LINES ) GAL PER. MIN PUMPS 301 3 425 4 512 603 5 676 6 739 794 853 7 904 GAL PER MIN PUMPS 319 3 451 4 552 5 638 713 6 782 844 7 902 957 8 DEPTH IN FEET 4 5 6 7 8 9 AREA OF HOLE =19.65 SQUARE INCHES AREA OF PLUG =12.25 SQUARE INCHES A~EA OF LEAK = 7.40\SQUARE INCHES DEPTH GAL IN PER FEET MIN PUMPS 1 91 2 129 158 4 182 5 204 224 241 258 9 273 3 AREA OF HOLE= 21.0 SQUARE' INCHES AREA OF PLUG= 15.0 SQUARE INCHES AREA OF LEAK=-6.0\SQUARE INCHES Figure 69. Effect of plugging holes. AGO 5244A WRAP PLUG WITH CLOTH BEFORE INSERTING COMBINATION OF CONICAL AND SQUARE ENDED PLUGS USED IN STOPPING LEAKS Figure 70. Typical use of wooden plugs as leak stoppers. many conditions, especially in holes not over 3 by 3 inches. Every vessel should have a large assortment of conical, square-ended, and wedgeshaped plugs at each repair station. The plugs should not be painted, as (2) Combinations of conical, square-ended, and wedge-shaped plugs can be used to get better conformation with the shape of the hole. It is best to wrap the plugs with lightweight cloth before inserting. The cloth will help the plugs to grip better. In most cases, wooden plugs will not make a watertight fit, but by chalking the area with rags, oakum, and smaller wedges, the entrance of water can be greatly reduced until a more permanent repair can be made. Square ended plugs hold better than conical plugs in holes in plating of 1,4 inch or less in thickness (fig. 70). (3) Most wooden plugs are inserted from inside the vessel and have to contend with metal edges protruding inward. Plugs driven in from the outside will not have so much interference, but outside plugs cannot be tended readily, AGO 5244A unpainted soft wood absorbs water and grips better. The plugs should be stowed in canvas bags which are secured to the overhead and properly marked. Figure 71. Typical installation of plug to outside. and they do not hold up as well over extended periods of time. The use of a line, which is secured to the inboard end of a plug by a screw eye and made fast to a stanchion, will help to overcome this difficulty (fig. 71). Whether to insert a plug from inside or outside the ship can depend upon several factors such as access, flooding, and wreckage. b. Pillows, Mattresses, Blankets. Pillows, mattresses, and blankets can be rolled up and shoved into holes. They can be rolled around a wooden plug, or a timber to increase their size and to provide rigidity. Such plugs cannot be relied upon, as they have a tendency to be torn out of the holes by action of the sea. This is an expedient to retard the flow of water entering the vessel until a more suitable patch can be applied. Figure 72 shows the use of mattresses installed inside and outside the hull as a patch. Placing mattresses inside will reduce the possibility of the patch being knocked away by the sea. If innerspring mattresses are used, at least two thicknesses of blanket should be used as a facing. Feather pillows are not so effective for patches over a period of time as folded blankets. Feathers in the pillow get wet and tend to lump at one end. c. Cloth Plug. An effective method of plugging a hole near the waterline from the outside of the vessel, when difficulties prevent repair from the inside, is by using a fabricated cloth plug. The cloth plug is effective because it has flexibility, it adapts to irregular shapes, and it will absorb water and swell, giving it a greater fitting capacity (fig. 73). A conicaltype cloth plug can be made using 1;4-or %inch line and a blanket cut in strips. For example, to fabricate a cloth plug to insert in a hole 8 by 10 inches in diameter, accomplish the following: ( 1) Prepare core using approximately 3 feet of %-inch line. (2) Back-splice an eye in each end of core line. (3) Wrap core line with strips of blanket cut approximately 8 inches wide and 3 or 4 feet long. ( 4) Wrap at angle to core line making a cone approximately 2 inches in diameter at one end, 2 feet in diameter at the other end, and about 1% feet long. Figure 72. Example of hull patch using mattresses. Figure 73. Example of a fabricated cloth plug. WELDED HANDLING EYES NG LINE PREFABRICATED PLATE PA'fCH OF 1/4-INCH PLATE WITH GASKET ~'AS RETAINING STRIP PLATE PATCH SECURED STUFFED CANVAS GASKET IN PLACE BY HOLDING LINES Figure 74. Prefabricated plate patch. (5) Fasten layers of cloth together and to d. Plate Patches. One of the most useful precore line by stitching and serving. fabricated patches is made of a square piece of (6) Secure lines for handling and install10-pound, or 1,4-inch, steel plate (fig. 74). Oning plug. one side is a thick gasket placed near the edges. (7) Lower plug over side and pull plug in The gasket can be made from old rubber tireshole in place (fig. 73). or a thick tube of canvas stuffed with oakum or AGO 5244A 97 CIRCULAR STEEL PLATE PILLOW USED AS GASKET L----:--HINGED PATCH INSTALLED AND SECURED Figure 75. Hinged plate patch. AGO 5244A TYPICAL STEEL BOX PATCH WITH GASKET INSTALLED STEEL BOX PATCH INSTALLED UTILIZING SHORING STEEL BOX PATCH INSTALLED UTILIZING WELDED ANGLE CLIPS Figure 76. Typical steel box patch. cloth, and secured to the plate as shown in figure 74. At the center of the inner side, weld a ring or an eyebolt for securing a line to hold the patch close to the skin of the vessel. Another method often used is to drill a hole through the center of the plate and insert a line with the outboard end knotted through the hole. e. Hinged Plate Patch. A variation of the plate patch is called a hinged plate patch, which is a circular plate, 18 inches or less in diameter, cut in two, and· so hinged that it can be folded and pushed through a hole from inside the vessel. The plate should be fitted with AGO 5244A a gasket, such as a pillow, and also a line for securing to the vessel. Using water diving equipment, this patch can be applied over a submerged hole without going outside the vessel. This patch is for use over relatively small holes, as it has no vertical support to hold it in place. Figure 75 shows the components and installation of a hinged plate patch. f. Flexible Plate Patch. A flexible variety of the plate patch can be used over curved surfaces such as the turn of the bilge. The plate is made of lightweight sheet metal reinforced with parallel strips of light angle iron, welded in place about 6 or 8 inches apart. The plate is provided with four eyes for securing lines, and it should have some kind of a soft gasket on the facing surface. It is, in effect, a stiff, metal, collision mat. g. Collision Mats. Collision mats are large canvas mats covered on one side with long, hairlike fibers. They are hauled over the outside of holes and are held in place with various guys. These mats are a fire hazard and should be used with caution. k. Box Patek. ( 1) A box patch is suitable for use over holes having jagged edges protruding _.· inward. A box patch consists of a· steel box running in sizes up to 18 inches square and 6 inches deep. The box is open at one end and has a gasket placed along the facing edges. The gasket can be made of rubber or of canvas stuffed with oakum. The box is placed over the hole from inside the vessel and is held in place with shoring. When the compartment is pumped dry, the box can be secured by welding angle clips between the box and the hull plating; the shoring timbers can then be removed (fig. 76). (2) The box patch cannot be readily fitted to rumpled surfaces; therefore, variations have to be made to its use. One variation is to stuff the box with pillows or to lay pilows over the hole before applying the box. Another variation is to stuff rags and wedges into holes between the box and the rumpled hull. Wooden boxes can be used. The advantage of a wooden box is that its edges can be shaped with a hatchet to fit closer to corrugations in plating. i. Bucket Patek. An ordinary galvanized bucket can be used in a variety of ways to stop leaks. It can be pushed into a hole bottom first to form a metal plug; or it can be stuffed with rags and put over a hole similar to the box patch described in h above. It can be held in place by shoring or by using a hookbolt. j. Use of Hookbolt for Securing Patek. A hookbolt is a long bolt having the head end shaped so that the bolt can be hooked to plating through which it has been inserted. '100 Figure 77. Types of hookbolts. The common types are the T, J, and the L (fig. 77). The long shanks are threaded and provided with nuts and washers. Steel or wooden strongbacks are used with them. The bolt has no regular head. The head end of the bolt is inserted through a hole and the bolt rotated or adjusted until it cannot be pulled back through the hole. A pad or gasket, backed by a plank or strongback, is then slid over the bolt, and the patch secured in place by taking up on the nut. It is generally necessary to use these bolts in pairs. Figure 78 shows an installed patch using two J-type hookbolts. Hook bolts can be used in combination with various patches such as the folding plate, the box, and the bucket. AGO 5244A GASKET (PILLOW) Figure 78. Example of patching using hookbolts. k. Use of Folding T for Securing Patch. A variation of the hookbolt is the folding T (fig. 70). It resembles the T-type hookbolt, but it has a hinge where the shank joins the cross piece so that it is similar to a tumble toggle bolt. This bolt can be folded and inserted through a small hole. When it is pulled back, the cross piece catches on the hull plating. Using this bolt, a man standing inside the vessel can put on a patch either inside or outside the vessel. Using a retaining line on the bolt, a strongback and a pillow can be threaded over the line and the entire patch folded and tossed out through the hole. When the line is hauled in, the patch takes up against the vessel where it can be readjusted to give a tighter fit; or the pillow and plate can be pushed over the bolt shank inside the vessel, providing an inside patch. Nuts and washers are provided for holding and tightening the patch. Tightening the patch can be facilitated by welding large wings on the nuts. l. Welded Patches. ( 1) Many large holes in decks and bulkheads have been successfully repaired by welding on steel pl.ates. It can be necessary to make one of the temporary patches described above while preparations are being made to weld on steel plates. To weld on a flat steel plate requires that all protruding edges be cut away with an oxyacetylene torch or a pneumatic chisel. Caution: Neither of these tools can be used where gasoline or other explosive vapors are present. Before using any flame or spark-producing repair equipment, test the air for the presence of explosive fumes; have a CO. extinguisher and a fire hose available. (2) A great deal of work can often be saved in clearing a hole for repairs if HINGED JOINT the patch is applied to the side on which the projectile entered. Depending upon conditions of the sea, a patch can be applied to the outside of the hull by lowering a welder and his gear over the side in a boatswain's chadr. The immediate application of welded patches is generally confined to those which can be made on decks and interior bulkheads. (3) A steel plate can be held lightly in place by tack welding, after which the DAMAGED HULL NUT Figure 79. Example of patching using the folding T hookbolt welder can go around the plate with a solid bead, not only to hold it securely in place, but also to stop all cracks. If the plate is large, it must be reinforced on the back with welded stiffeners and possible with shoring. If this precaution is not observed, the welding can crack. The path can open wide and act as an air scoop so that the vessel will actually be in worse condition that it was before the plate was installed. -"-GO 5244A CRACK 1/4-INCH DRILLED HOLES A· STOPPING A CRACK FOR PATCHING WOOD BLOCK B ·PATCHING A LEAK C ·CLAMPING TO PATCH A LEAKING FRAME Figure 80. Methods of stopping leaks. m. Patching Miscellaneous Leaks. (1) A fairly common type of leak is a crack in a steel plate. If the leak is in a flat surface away from frames and other interferences, it can generally be stopped by scraping the surface smooth and applying a patch of sheet packing backed by a shole (fig. 80). AGO 5244A This can be held in place with shoring. An example of this is a crack around a welded port insert. If the crack is adjacent to a frame, it can be necessary to use oakum held in place by the corner of a timber. Advantage should be taken of adjacent framing to use clamps for holding the stopper in place (fig. 80). Upon reinspecting a crack, if it has· increased in length, drill %-inch holes in the extreme ends of the crack and plug the holes. If time permits, weld a plate over the crack. (2) Wedges, especially hardwood wedges, should not be driven into cracks in thin plating, as the wedges tend to open the cracks. Marline, oakum, and rags can often be used as effective calking materials. Among the · most difficult holes to plug are torn seams or loose bounding bars where deck and bulkhead plates are joined. Rags, oakum, marline, soft-wood wedges, shingles, lead strips, lead wool, metal calking, and various plastics have been used to plug such leaks (fig. 81.) These materials are applied on the unflooded side, but because of movements of the plates, the cracks open and close. This permits the plugging material to be washed out. Concrete held in place by a wooden cofferdam has been used effectively in stopping such leaks (fig. 82). Leaky riveted seams should not be welded, as the intense heat will cause adjacent rivets to leak. n. Doors and Hatches Sprung by Blast. Doors and hatches sprung by blast can often be made tight with shoring. If small spaces are open between the closure and the knife edge, these can be treated as cracks. In some cases, the damage is so bad that it is better to remove the closure entirely and to replace it with a mattress backed by a shored plate. Armored hatches present a peculiar problem, especially when the surrounding decks are warped. In some cases, the best remedy is to cut the hinges, after which the hatch will fall back into its proper place. A -CALKING CRACKS WITH OAKUM OR CLOTH B -CALKING DECK SEAM WITH OAKUM C-CALKING WITH SOFT WOOD D -CALKING AND BRACING BULKHEAD SEAM Figure 81. Stopping leaks by calking methods. AGO 6244A Ml XED CEMENT .ANGLE IRON SEAM Figure 82. Stopping leaks with cement and coffe?·dam.. o. Leaky Stuffing Tubes. ( 1) Stuffing tubes around electric cables often leak because they are not properly packed or because the packing has hardened with age. Tightening up on the packing nut will sometimes stop the leak. Marline, oakum, and very small wedges have been used effectively. Periodic air tests of stuffing tubes should be made. (2) Some leaky shaft glands can be repaired by tightening up on the nuts. In others, the studs have been broken so that it is necessary to shore the entire gland back into place, preferably with welded braces. Where the leak is extremely bad, a type of box patch in two sections can be secured around the shaft and welded over the gland. (3) Leaky rivets are difficult to repair. Frequently, rivets are pulled through plating but remain so close that wooden plugs cannot be driven home. Slugs cut from sheet lead, lead wires, marline, and red lead or calking can be used to stop leaks around rivets. p. Use of Cofferdams as Leak Stoppers. ( 1) A method frequently employed in enclosing large holes involves the use of cofferdams. A cofferdam, in this case, would be an additional bulkhead built around the damaged area. The steel box described in h above is a prefabricated cofferdam of limited size. For use during and immediately after damage, cofferdams are installed inside the vessel. Outside cofferdams are ordinarily used in salvage operations. A cofferdam can be built up of steel plates or heavy planks, either directly supported by frames and stanchions or held securely in place by shores. When constructed, it can be partly or completely flooded. (2) Conditions seldom permit the construction of a watertight box. It is more practical to build a strong retaining bulkhead around the hole and leave the box open at the top, then drop in mattresses, pillows, bales of waste, or clothing until it is full. As most of these materials will float, they will have to be weighted to get them down to the bottom of the cofferdam. When the box is full, the stuffing materials are held down by iron bars or shores. A cover can be put on the top if desired. A cover is more reliable than shoring, although the entire structure should be strengthened around by shores. The fibrous stuffing materials will act as calking materials to exclude water. It is possible that the hole will be so large that mattresses or bales of rags could fall out through the side of the vessel. This can be prevented by installing a grating of crossed pipes, timbers, or angle irons over the hole before at- AGO 5244A 105 tempting to stuff the box. Cofferdams can be made to cover holes in either vertical or horizontal plating. (3) Cofferdams can also be built around hatches, trunks, and doors when it becomes necessary to go from a dry through a flooded compartment to another compartment. The cofferdam must be large enough to permit opening the door. The spr:ead of flooding HEAVY BARS MAY BE WELDED OR BOLTED INTO THE WEB ACROSS THE BREAK must not be permitted. If steel plate and a welding machine are available, a most effective cofferdam can be fabricated. It is important that the cofferdam be securely welded. If time is not available to make a watertight weld all around, the cracks should be calked with oakum. Cross bracing or shoring wil be necessary if the water is deep in or around the cofferdam. A NEW BAR SET ON IT'S EDGE, MAY BE WELDED OVER THE WEAKENED AREA AND BUlLTUPAS AT-BEAM THE ENDS, AND END FLANGES MUST HAVE A FLAT SLOPELESS THAN 30 DEGREES ORIGINAL BEAM NEW WEB WELDED IN PLACE Figure 83. Beams and frames. 106 AGO 6244A q. Preparation of Wooden Cofferdam. For a wooden cofferdam, use planks, preferably tongue-and-groove cut. Cleats should be installed across the. boards of each side, and the corners locked securely with cross nailing or metal strips. The cofferdam should be pressed down tightly to the deck with adequate shores from above, and all cracks and seams calked with oakum or cloth. Shoring should be provided to support the walls against water pressure. It can be necessary to put a portable suction pump unit inside the cofferdam with an open top to remove water leakage. When using a cofferdam as a means of access between flooded and nonflooded areas, the cofferdam must be strongly built and firmly secured, as the safety of the vessel is imperiled. r. Strengthening Hull Structure Members. (1) Beams, frames, decks, and some bulkheads are strength members of the hull structure and if they break or become weakened, the hull can collapse and the vessel break in two and sink. Generally, a small vessel does not have the necessary equipment to weld on heavy rails or angle irons to give additional support, but some help can be afforded by shifting weights to reduce the strain and also by shoring. Beams and frames can be patched or strengthened by bolting or welding doubling plates or bars along the webs (fig. 82). (2) Supports for heavy equipment can be pushed back into place with screw jacks and shoring and later secured with stanchions made of heavy pipe welded in place. Chainfalls and heavy wires, possibly fitted with turnbuckles, can be useful in pulling plating and equipment back to their original positions. Supports under dislocated machinery must often be carried down several decks because a single deck might not have the strength to support all the weight. It can be necessary to make successive supports down to the bottom frames. In shoring heavy weights, the butt of the shore should be placed on a solid frame, or the weight spread between two or three frames by sholes and cross-timbers. AGO 5244A s. Strengthening Cracked Supports Under Machinery. Some strength -can be restored to cracked, fractured, or weakened supports under machinery by welding on side plates or angle irons, as illustrated in .figure 84. Strengthening can also be accomplished by the use of concrete collars. Use about one part of cement, two parts of sand, and two parts of small pebbles to mix mortar. Build a light form around the damaged part. Fill the inner space with concrete mortar and do not subject it to vibration or movement until the collar has set. 108. Shoring Shoring is often used to support ruptured decks, strengthen weakened bulkheads and decks, build up temporary decks and bulkheads against the sea, support hatches and doors, and provide support for equipment which has broken loose. a. Shoring Materials. The basic materials required are shores, wedges, sholes, and strongbacks. A shore is a portable beam. A wedge is a block which is triangular on the sides and rectangular on the butt end. A shole is a fiat block which can be placed under the end of a shore to distribute the pressure. A strongback is a bar or beam of wood or metal, often shorter than a shore, which is used to distribute pressure or to serve as an anchor for a patch. b. Tools and Equipment. Many items of tools and equipment are used when shoring. These include wooden battens, claw hammers, mauls and sledges, handsaws, mattresses and pillows, axes and hatchets, wood clamps, chainfalls, electric welding machines, oxyacetylene cutting outfits, cold chisels, wood chisels, nails, wooden plugs, packing sheets, turnbuckles, screw jacks, hydraulic jacks, bolts, nuts, and washers. Much of this equipment is authorized and normally carried aboard each vessel. Major items, such as welding machines and oxyacetylene cutting equipment, cannot be aboard due to the size of the floating draft. Quantities of items can also vary based upon the size and type of vessel. c. Proper Wood for Shoring. The best woods available for shores are Douglas fir and yellow pine. Hemlock and spruce can be used, but they are not as strong. The wood used for shores WELD FLAT BAR STIFFENER SET UP A BRACKET STRENGTHENED BY ANGLE IRON STIFFENER WELDING ON A FLAT BAR FLANGE MADE BY WELDING FLAT BARS ON EDGE AND WELDED AT RIGHT ANGLES TO EACH OTHER Figure 84. Example of stiffener fabrication. 1-------LENGTH VARIES -------1 AND IS ADJUSTED TO SUIT CONDITION GALVANIZED 16 GAGE STRAP LENGTH LOCKING DEVICE GALVANIZED STRAP ADJUSTABLE SHORE MEASURING BATTEN ANGLE LOCKING DEVICE Figure 85. Adjustable shoring batten. should be straight grained and relatively free from knots and cracks. Shores should be treated with a fire-resisting chemical and should never be painted with an ordinary paint. d. Length of a Shore. In use, the length of a shore should never be more than 30 times its minimum thickness; therefore, a shore that is 4 by 6 inches should not be longer than 10 feet. The shorter the shore is in relation to its thickness, the greater the weight it will support. Shores are usually carried on the vessel in 16-to 18-foot lengths and are cut to required length when needed. e. Measuring and Cutting Shores Using a Bntten. The most rapid and accurate way to measure shores for cutting is by using an adjustable shoring batten. An adjustable shoring batten, such as the one shown in figure 85, can AGO 6244A BULKHEAD---· STRONGBACK---=~ l A / / / / .... -- ."'" 4FT "' / "' SHORE DECK I~~:=====~-7-~-1-IN_·=====:.I~·I 6 FT 9 IN. RATIO OF 1 INCH =1 FOOT 6 FT 9 IN. A A LENGTH OF SHORE IS 7 FEET 10 INCHES Figure 86. Measuring length of a shore. be made from materials aboard the vessel. To use the shoring batten, extend it to the required length and lock it with the thumbscrews on the length locking device. Measure the angles of cut by adjusting the hinged metal pieces at the ends of the batten, and lock the angle locking device in place. Lay the batten along the shore, and mark and cut the timber to the proper length and angle. Shores should be cut 1;2 inch shorter than the measured length to allow space for wedges. f. Measuring and Cutting Shores Without a Batten. If a shoring batten is not available, measure the shores for length by using a folding rule or a steel tape and a carpenter's square, as follows: AGO 6244A (1) Measure distance A (fig. 86) from center of strongback to deck. Then measure distance B from edge of anchorage to bulkhead, subtracting thickness of strongback. (2) Lay off, on a carpenter's square, measurements A and B, using ratio of 1 inch to 1 foot. (3) Measure diagonal distance between A and B. In the example given in figure 86, this distance is 7% inches. The distance in feet would be 7% feet, or 7 feet 101;2 inches. Subtracting lj2 inch for wedge space, the required length of the shore is then 7 feet 10 inches. g. Trimming and Fitting Shores. Shores must be trimmed to fit the shoring structure, and the trimming must be done in such a way as to prevent splitting or chipping of the shores. If shore A in figure 87 is to fit against a plane surface of shore B, and if it must take a load in compression, the end of shore A must be cut square and perpendicular to the long axis of shore A. Sharp points must never be used when shoring is required to withstand pressure. Figure 88 shows the correct way to fit shores to present a flat surface at each pressure area. The carpenter's ·square can be used to measure the angles of cut and to mark the shore for cutting. Shores are sometimes notched at the end to fit against other shores, but this method should not be used if any great pressure is to be expected. A safer method is to cut a socket in the side of one shore and fit the butt of the other shore into the socket. This method is shown in figure 89. Figure 87. Fitting shore to shore. Figure 88. Fitting shore to deck. Figure 89. Socket cut in shore. h. Shoring Bulkheads. Most shoring of bulkheads is done to support bulkheads which are endangered by structural damage or weakness caused by the pressure of flooding water. Methods of shoring bulkheads are shown in figures 90, 91 and 92. Observe the following when shoring bulkheads: ( 1) Allow a large margin of safety in number of shores used. (2) Spread pressure. Make full use of strength members by anchoring shores against beams, stringers, frames, stiffeners, and stanchions. Place legs of shoring against strongback at an angle of 45° or 90° if at all possible. (3) Do not attempt to force a warped, sprung, or bulged bulkhead back into place. Place shoring so that it will hold bulkhead in its warped or bulged position. (4) Strengthen main shores, when possible, with auxiliary shores, as shown in figure 92. Notice that strength members A, B, C, and D have been locked in place with auxiliary shores E and F to keep them from jumping out as the ship works in the seaway. Cleats H and J hold E in place. i. Shoring Hatches or Doors. The general principles of shoring bulkheads described in h above apply to shoring a hatch or a door. The entire hatch or door should be shored and the pressure should be spread over both the hatch cover or door and the supporting structure, as shown in figure 93. Hatches and doors are the weakest part of the bulkhead or deck in which they are installed. j. Strongbiwks. All or part of an ordinary shore can be used to make a strongback. Shoring scraps should be kept for use as strongbacks and short shores. Heavy planks, steel bars, angle irons, and pipe can also be used as strongbacks. k. Wedges. As the shoring job progresses, check carefully to see that all wedges are exerting about the same amount of pressure on the number being shored (fig. 94). Use as few wedges as possible to obtain satisfactory results. Wedges are usually made of soft wood, preferably fir or yellow pine. A few hardwood wedges should be kept on hand for special use where resistance to crushing is required. When hardwood wedges are used, they must be check frequently, as they have a tendency to work loose. Wedges should be approximately as wide as the shores with which they are used. They should be cut with a coarse saw and left unpainted to absorb water and hold better. They can be made with various angles at the leading edge. Blunt wedges do not hold as well as sharp ones. A wedge should be about six times as long as it is thick. Thus, a wedge to be used with a shore that is 4 by 4 inches should be about 4 inches wide, 2 inches thick, and 12 inches long. Always drive wedges uniformly from both sides so the shore end will not be forced out of position. Lock wedges in place so that they will not work loose and cause the shoring to slip (fig. 95). AGO 62UA -STRONGBACK THIS IS THE SIMPLEST AND STRONGEST SHORING STRUCTURE. THE BASIC STRUCTURE IS REPEATED AS OFTEN AS NECESSARY. ADDITIONAL STRENGTH IS AFFORDED BY SHORES B AND C. HORIZONTAL SHORE B IS SUPPORTED BY D AND A, AND IS BRACED AGAINST MACHINERY BY MEANS OF E. THE USUAL METHOD OF INSTALLING SHORES IS BY A TRIANGULATION SYSTEM. WHEN OBSTRUCTIONS PREVENT USE OF THE TRIANGULATION SYSTEM THIS METHOD MAY BE USED. Figure 90. Shoring against horizontal pressure. AGO 6244A SHORE SHOREs-PERPENDICULAR TO BULKHEAD EXERT MAXIMUM PRESSURE. SHORES MUST FORM A CONSIDERABLE ANGLE WITH THE BULKHEAD THEY ARE SUPPORTING. ANCHOR SHORES AT A AND B WHEN THE ANGLE OF THE 2 SHORES (X) IS GREATER THAN 90 DEGREES, THE EFFECTIVENESS OF THE SHORES IS LESSENED. Figure 91. Correct shoring f!mgles. l. Use of Sholes. Sholes (fig. 96) should be made of Douglas fir or yellow pine planks 1 inch or more in thickness and from 8 to 12 inches wide. Wider sholes can be made by nailing cleats across two or more widths of planking. Single planks can be cleated at the ends . to keep them from splitting. 109. Piping Repairs Repairs to piping systems are classified as permanent or temporary. The type of repair to be made at any given time depends upon the circumstances. Permanent repairs are made when the system can be shut down or the damaged section can be isolated, and when the material is available for permanent repairs or replacements. A repair is considered permanent if it restores the piping system to its original serviceability, and if the repair can reasonably be expected to last for the life of the system. Temporary repairs are usually made by securing some type of patch over the damaged section of pipe. The material used for the patch depends upon the type· of piping that is being repaired. A good general rule to follow is to make the temporary patch from the same type of material that is used for the flange gaskets in the system. Temporary repairs are made when the system cannot be shut down or the damaged,section cannot be isolated. All temporary repairs should be replaced by permanent repairs as soon as practicable. a. Soft Patches. ( 1) Small holes or cracks in low pressure (150 psi) piping can often be repaired by soft patches (fig. 97 and 98). When possible, the area of the hole should first be reduced by driving in softwood wedges covered with cloth. They should not be driven in too far or they will retard the flow of fluids. The wedges should be trimmed flush with the outside of the pipe. The area should then be covered with a strap of sheet or rubber packing held tightly in place by two layers or marline or wire. The packing should extend about 2 inches on each side of the hole. The soft patch can be modified or improved to suit immediate conditions. Sometimes a curved plate of lightweight sheet metal between the packing and the binding and a coat of white or red lead on the face of the packing are used. (2) Marline and oakum have been used successfully as a calking material in cracks. On sharp curves where it is not possible to use sheet packing, combinations of wedges, marline, and plastics will often make effective patches. Small cracks adjacent to flanges can be calked. b. Use of Thumb Clamps and C-Clamps. C clamps and thumb clamps can be used to hold plugs or patches in place (fig. 99). For example, a block of softwood can be roughly shaped to AGO 6244A THE STRENGTH MEMBERS A B, C, D, HAVE BEEN'LOCKED INPLACE W-ITH AUXILIARY SHORES -!:AND F TO KEEP THEM FROM JUMPING OUT AS THE I VESSEL, WORKS. CLEATS H AND J HOLD E IN PLACE. RELATIVELY LONG SHORES WHICH SUPPORT WHEN ONE SHORE IS LONGER THAN THE HEAVY PRESSURE, MAY HAVE A TENDENCY OTHER, A WIDER STRONGBACK WILL TO BOW. SUPPORTING SHORES A, B, C, SHOULD KEEP THE LONGER ONE FROM SLIPPING. BE INSTALLED FOR GREATER STRENGTH. Figure 92. Strengthening shores. fit over a damaged area in a pipe, and the pad can be held tightly in place with thumb clamps. Care must be taken to reinspect patches held in place by clamps, as they have a tendency to work loose under shock or vibration. c. Jubilee Pipe Patch. The jubilee pipe patch (fig. 100) is a modification of a commercial hose clamp. It consists of a piece of sheet metal which is rolled into a cylinder and shaped at the gap so that the two ends form flanges. These flanges can be reinforced by welding on strips of iron. The flanges are drilled for three to five bolts. It is advisable to weld small braces from the flange to the back of the patch to the gap so that the two ends form flanges. keep the flange face nearly parallel under pressure. The sheet metal in the body of the patch should be as heavy and strong as possible, but it should be capable of being sprung or bent so that the gap will go over the pipe to be repaired. A sheet of packing is first put over the hole, extending over each side of it. The AGO 6244A 113 TOP VIEW Figure 93. Shoring a hatch. jubilee clamp is then sprung open and clamped over the packing. When the bolts are tightened, this patch will easily hold up to 100 pounds of pressure. d. Welding and Brazing. Repairing leaks by welding, brazing, and silver soldering is limited because these methods are slow and can cause fires or explosions. Only skilled personnel can repair leaks by these methods. e. Repair of Steam Lines. Soft patches can be used for low pressure steam lines. Rubber packing will melt and make an offensive odor, but it will vulcanize and make a tight patch. A 150-psi steam line can be repaired by wrapping the crack with marline dipped in red lead putty. A paste of litharge and glycerine can also be used. After making such a repair, cover the affected area with a burlap bag to reduce the danger of injury to personnel from hotdrops. f. Fuel Line Repairs. Soft patches are not recorrimended for the temporary repair of gaso 2 WEDGES FROM TAPER OF WEDGE SQUARE BLOCK USE BLOCK FOR DRIVING DRIVE FROM BOTH CLEATS PREVENT SIDES UNIFORMLY WEDGE SLIPPAGE Figure 94. Use of wedges in shoring. AFTER WEDGES HAVE BEEN CUT BLOCKS OF 2X4 DRIVEN IN, CUT THEM OFF TO FIT tHE GAP AND .ALONG LINE A TAP THEM IN S"f.IUGLY Figure 95. Locking wedges in place. Figure 96. Use of a shole. AGO 6244A DAMAGED AREA DRIVE IN SOFT WOOD PLUGS CUT OFF PLUG COVERED WITH CLOTH FLUSH WITH PIPE · BIND WITH MARLINE OR WIRE WRAP WITH SHEET PACKING BACKED BY LIGHT SHEET METAL OVERLAP ENDS OF CRACK 21N. Figure 97. Installing a soft patch. line lines because the slightest leak would create a fire hazard. It is safer to renew the damaged section. If adequate time is available, a concrete collar might be effective. When a fuel line has been damaged, immediate action should be taken to repair the damage. Care must be used to guard against fire and explosion. The following safety precautions must be observed when repairing fuel lines: (1) Locate damaged area and isolate section by closing and securing valves in such a manner that they cannot be opened accidentally, locally or remotely. Lock valves or wire closed and attached warning tag. (2) Drain damaged line completely and insure that no pressure is on line. (3) Clean area of spilled fuel by washing down if necessary. STEP 1 STEP 2 STEP 3 STEP 4 COMPOUND RUPTURE REPAIR PIPE STEP 1 STEP 2 STEP 3 WOVEN ROVING COVERED WITH SHEET OF PVC FILM AND Tl ED WITH CHALK LINE SIMPLE RUPTURE REPAIR Figure 98. Installing a patch over simple and compound ruptures. AGO 6244A 115 f-..,..>...;--' THUMB CLAMP PAD AND BLOCK IN PLACE HELD WITH THUMB CLAMP Figure 99. Pipe patch held with thumb clamp. AGO 6244A THREE TYPES OF CLAMPS PACKING PIPE PATCH: SHEET METAL COLLAR SECURED OVER PACKING WITH NUTS AND BOLTS Figure 100. Jubilee pipe patches. (4) (5) (6) (7) AGO 5244A Insure that area is thoroughly ventilated before and during repair OJ:eration to prevent accumulation of fl2mmabie vapors. Deenergize all electrical equipment in area and cover with waterproof material if splashing is possible. Do not weld or braze damaged section while connected to system. Allow no unauthorized personnel in repair area. (8) Observe NO SMOKING precautions during all fuel repair operations. Place NO SMOKING AREA signs on both sides of repair area to warn personnel not concerned with repair operations to stay clear while smoking. (9) Insure that adequate fire extinguishers are available. Insure that extinguishers are carbon dioxide, or equivalent type. (10) Use only spark proof tools and equip HOLE AREA OF HOLE WIRE WHEN USING A CLAMPING TOOL, LAY A WIRE BETWEEN THE GASKET AND METAL BACKING PLATE IN MAKING CLAMPS ALLOW FOR THICKNESS OF GASKET ET "--±-../LOCK ~ WASHER CLAMP MADE OF SHORING TIMBERS AND BOLTS ~ FOR LOW PRESSURE LINES FORGED HEAVY-DUTY CLAMP NUT Figu1·e 101. Pipe clamps. AGO 5244A ment when making repairs to damaged fuel lines. (11) Use only spark proof flashlights in repair area. (12) Wear only expl6sion ptoof clothing, free from steel buttons or tn'etal belt buckles, during fuel repair operations. Do not wear buckles or clothing made of synthetic fibers such as nylon. ( 13) Station safety guards on each side of dHmaged area when possible. (14) Insure that repair equipment includes breathing respirators to protect repairmen from fuel vapors. g. Renewing Sections of Pipe. (1) If the pipe has been badly holed or ruptured, patching might not suffice and it can be necessary to renew the damaged section. It would be advisable, therefore, to carry spare sections of the smaller sizes of important pipes aboard. In an emergency, it could be possible to remove a section from an unimportant system to use where the need is more urgent. If the original pipe was fitted with screw flanges, remove the entire damaged section. Cut screw threads on the new piece, screw the flanges onto the new piece, and bolt the flanges together. ( 2) To renew only the damaged part of a small pipe, accomplish the following: (a) Cut out damaged area. (b) Cut piece of pipe almost same length as gap. (c) Cut screw threads on all exposed ends of pipe and make up joints by using pipe unions and coupling. (d) Cut filler piece short enough to rermit inserting pipe fittings. (e) Apply white lead or paint to screw threads to seal joints. h. Special Tools-Hand-Clamping Devices. Most large vessels are provided with a handclamping tool, together with the necessary metal straps, clamps, and complete directions for its use. It is useful in securing soft patches and in securing hoses to couplings and pipe. There are a number of patent clamps and couplings which are easy to install, involve no pipe threads, and generally make tight joints. Each item fits only one size of pipe and is usually. heavy and limited in its use. Pipe clamps can be fabricated by using scrap shoring timbers. Drill holes in the clamp sections and hold the clamp in place with bolts and washers. Another suitable pipe clamp can be made by forging the clamp sections using scrap iron (fig. 101). i. Blanking Lines. ( 1) Ruptured pipe lines are often a menance because they cannot be isolated readily and still have the system perform a vital function. In the case of fire mains, the choice can lie between flooding a compartment or extinguishing a fire. If oil lines are leaking, important and undamaged machinery often must be secured. Such problems have been solved by blanking off part of the pipe line. Lowpressure pipe lines can often be blanked off by driving in wooden plugs covered with cloth. Unsupported, these plugs have a tendency to back out. Adequate support can generally he provided by using shores or jacks or by drilling a hole through the pipe and pinning the plug in place. For frayed ends of pipe, combinations of plugs can be desirable. When the damaged pipe is joined by screw fittings. it is a simple matter to unscrew the damaged part and to stop the flow of fluid by a pipe cap or a pipe plug. (2) Where the joints are made up with flanges, blank flanges can be used. A blank flange is a flat plate of heavy metal, circular in shape, and provided with standard bolt holes. A gasket of sheet packing is normally used with most low-pressure flanges and special gaskets on steam lines. When possible, such gaskets should be ·. used when making emergency repairs to prevent excessive leakage. (3) One type of flange resembles a blank flange, except that the center is cut away and the hole is surrounded by a short pipe having screw threads. It is called an adapter. The flange can be bolted to any similar flange on a pipe AGO 5244A line, and a hose can be coupled to the pipe threads, permitting a jumper to be used. (4) In order to save time and to have everything ready for use, all flanges in repair lockers should be made up with studs, nuts, and gaskets attached to them. j. Joining Odd-sized Flanges. Flanges normally are standard; however, a case can arise in which it is desirable to connect flanges of different sizes of pipe. When the bolt holes of odd-sized flanges of the same outside diameter do not line up, matching holes can be drilled and topped to permit the flanges to be bolted together. As a temporary measure, odd-sized flanges can be secured by inserting a gasket between the two flanges and holding them together with heavy C-clamps. At least four clamps are required. k. Repairing Vacuum Leaks. Vacuum leaks occur mainly in. the engineering compartments. The difficulty of these leaks is that they are often inaccessible or obstructed in such a way that ordinary patches cannot be applied. Fireproof plastics and putties can be applied, possibly in conjunction with muslin. Rubber tape, friction tape, and cellophane tape have also been used effectively. l. Glass Reinforced Plastic. Temporary re pairs to some piping systems can be made by using plastic materials. The materials required for plastic patching are furnished in a special kit. This special plastic repair kit can be obtained from Navy supply sources using stock number HF 2040-372-6064, Military Specification MIL--R-19907. m. Testing Procedures. Piping sections that have been removed for repair and for newly fabricated ·sections will have to be hydrosta tically tested before they can be permanently installed to insure that there will be no leaks under operating conditions. The tef'\t of piping assemblies, except Freon 12 refrigeration piping, should be at a pressure one and a half times greater than the design pressure of the system, and in no case at a pressure less than 50 psi. The equipment required for hydrostatic testing includes blank flanges, gaskets, clamps, copper tubing, a hydraulic pump, and a pressure gage. One flange should be drilled, tapped, and fitted with a nipple of suitable size. Use C-clamps to secure the flanges with gaskets to the ends of the pipe. When connecting the test section to the pump, install a cutoff valve between the pipe and the pump and a pressure gage between the valve and the pipe. After the pipe is completely filled with water, build the pressure up to the specified amount and maintain it for at least 15 minutes. When the pressure valve is closed, the pressure gage needle should remain steady. A drop in pressure indicates that there is a pinhole leak. It there is a large leak, it will be impossible to build up pressure. The pipe should be carefully inspected while under pressure. If leaks are found, retest the section after the leaks have been repaired. When the repaired section can be isolated, only that portion of the system need be tested. 110. Recovering Sunken Vessels It can be necessary, during a marine operation, to recover a sunken vessel that is partially or completely under water. The cause can be the result of collision, storm, grounding, or combat damage. To attack the problem successfully, determine the extent of damage to the sunken vessel and the availability of qualified personnel, recovery equipment, and repair material. In many cases, underwater and tidal conditions and depth of water will affect the recovery operations. a. Methods Used for Recovering Sunken V essels. Basically, there are four methods used in recovering sunken vessels: (1) Patching and pumping. This method is used when the sunken vessel is in shallow water. If the sunken vessel has an installed pumping system, obviously this system can only be used when the deck is above the surface of the water. (2) Using compressed air. This method is accomplished by filling the vessel with compressed air after patching the damage. The compressed air is pumped into the hull and, as the water is displaced, the vessel becomes buoyant and rises. This method is considered difficult, as it has a great effect on stability. An advantage of this method is that it can be used in much deeper water than other methods. AGO 62UA Figure 10$. Typical cylinder pontoon. (3) Using pontoons. See figure 102. When employing this method (fig. 102), many objects can be considered and useu as pontoons, commonly called camels. Items that can be adopted as pontoons are 6-foot square metal mooring cubes, empty 55-gallon oil drums, large steel cylinders, and flexible canvas air bags. Pontoons can be placed in the hull or secured to the outside using line or cable. Fill the pontoons with water, sink them, and place them in the desired position. After they are placed and secured, replace the water in the pontoon with compressed air. Flexible canvas air bags are lowered and positioned in a collapsed state, secured, and inflated. The pontoons then raise the vessel by their buoyancy (fig. 103). The size and AGO 6244A quantity of pontOons govern the size of the vessel they can raise. Pontoons are very usefu'l in conjunction with the other lifting methods. (4) Using lifting vessels and cables. In this method, two or more lifting vessels are positioned, in equal numbers, on each side of the vessel to be raised. Floating barges, floating cranes, and other floating craft can be used as lifting vessels. Wire rope lines are swept or passed under the hull and secured to the lifting vessels on the surface. Care must be taken to insure an equal distribution of the weight of the vessel, being raised. Then the vessel can be lifted either by pontoons or by mechanical means. The tide can be used to assist the lifting vessels in raising the sunken vessel. After pass Figu1·e 103. Recovering sunken vessel using pontoons. ing the lines under the sunken vessel, secure the lifting lines at dead low tide. As the tide rises, the sunken vessel is lifted off the bottom. As soon as this happens, tow the lifting vessels toward shore until the sunken vessel grounds again. A·t the next low tide, take up the developed slack on the lifting lines, securing or pinning the lifting vessels to the vessel being raised. When the tide rises again, the process is repeated until the decks of the sunken vessel are exposed at low tide (fig. 104). Now the sunken vessel can be patched and pumped out. Ingenuity and the use of field expedients are required to recover sunken vessels. b. Varied Conditions Encountered. There are many conditions that will be encountered when confronted with recovering a sunken vessel. Some of the major conditions are as follows: ( 1) N onavailability of necessary supplies and equipment. (2) Nonavailability of required, qualified personnel. ( 3) Determining extent of damage to sunken vessel. (4) Tide, surf, and underwater obstacles. Underwater obstacles will include dangerous and poisonous fish. ( 5) Combat area conditions. c. Equipment Needed. The type and quantity of equipment needed to recover a sunken vessel will depend primarily upon the type, size, and damge of the sunken vessel. Various conditions that can be encountered, as listed in b above, and the method of recovering the sunken vessel will also affect equipment requirements. Some of the major items of needed equipment are as follows: (1) Heavy lifting equipment, such as a AGO 6244A Figure 10!,.. Recovering a sunken vessel using lifting vessels. floating crane or additional floating craft. (2) Diving equipment. (3) Air compressors. (4) Pumps. ( 5) Pontoons. (6) Welding and cutting equipment. (7) Generators. d. Tools and Materials. The type and size of the sunken vessel will also govern tool and material requirements. For example, if the vessel to be recovered has a steel hull, then metal working tools and materials will be required. Normally, the tools authorized ~md issued a AGO 5244A maintenance unit wiH be adequate; however, some situations can require additional tools. Generally, various quantities of the following material will be required to raise a sunken craft. ( 1) Patching material, such as wood and steel, based upon the type of vessel. (2) Wire rope, line, and chain. (3) Various items and sizes of ground tackle. ( 4) Miscellaneous hardware, such as bolts, rivets, and nails. e. Procedures Used for Various Conditions. In determ~ning the procedures to be used, consider all details of the following: ( 1) Type of sunken vessel. (2) Proper method of recovery. (3) Equipment requirements and availability. ( 4) Personnel requirements and availability. ( 5) Local tide and water conditions. (6) Combat conditions. f. Safety Precautions. In addition to observing standard safety precautions, such as fire prevention, diving safety, and general personnel safety precautions, the following should be observed: (1) When using compressed air to raise a sunken vessel, do not pump air into the vessel too fast, as it can rise quickly and with force causing injury to personnel and damage to equipment. (2) When using subdivided barges to raise a vessel by flooding and pumping barge empty with compressed air, exercise care in the use of compressed air. When subdivided barge has more air than water ballast it can flip, causing injury to personnel and damage to equipment. (3) Exercise care in attaching lifting hawsers, pontoons, and handling lines to vessel, as they can slip, causing in~ jury to personnel and damage to equipment. (4) Consider local tide and weather con, ditions as possible safe.ty hazards. 111. Drydocking Procedure a. Responsibility in Docking. U.S. Army vessels, requiring major repairs, are normally re~ paired by commercial shipyards under the provisions of Government contracts. The contrac .. tor of a commercial shipyard is responsible for the drydocking of a vessel as outlined in the' master contract for repair and alterations of vessels. A· U.S. Army marine inspector supervises all the work accomplished by the contractor including drydocking. Smaller craft, requiring minor repairs, can be hauled out on a marine railway and set in a cradle or on blocks at a U.S. Army installation. The installation marine maintenance officer or marine inspector is responsible for drydocking the craft and supervising repairs. b. Working Parties Handling Lines. When a U.S. Army vessel is being drydocked in a commercial shipyard under Government contract, all docking lines are handled by shipyard personnel because of insurance factors. c. Docking Arrangements. Docking details are outlined in the commercial repair contract and are accomplished by the contractor. The responsibilities of the contractor toward the vessel's complement during the repair period are included in the contract. After the vessel repair arrangements have been completed, the commanding officer of the unit to which the vessel is assigned or attached is notified of the time and place the vessel is to be delivered for repairs. d. Preparation of Drydock. ( 1) The arrangement of blocking for a vessel to be drydocked will be made in accordance .with the latest corrected docking plan. The master of the vessel is responsible for the correctness of the docking plan. Areas under blocks will be cleaned and painted by retracting one block at a time. If single block removal is not possible, the vessel will be refloated and redocked arranging all blocks in a different position. The contractor or responsible repair facility will also ascertain the nature of any planned underwater work and have blocking arranged accordingly. (2) The Contractor (repair facility) will insure that adequate shoring or means of insuring stability of side blocking is installed to resist possible earthquake or hurricane forces if the dry-· dock is located in an area subject to such disturbances . (a) There are basically three methods that can be used to prevent the overturning caused by earthquakes. These methods are stable side blocks, spur shores with side blocks, and wale breast shores with side blocks. The use of stable side blocks is the most desirable of the three methods. Wale shores and spur shores create interferences with dock work. AGO li244A (b) The two main considerations in side blocking to resist earthquake-type forces are that the maximum crushing strength of the side blocks should not be exceeded and that the side blocks must be stable. Stability of the side blocks can be insured by keeping the line of action of the side block reaction well within the base of the block. In some cases this will require the use of double pier blocks for each upper side block. It should be noted that the number of side blocks required can be reduced by increasing the effective area of contact. This can be done by using fitted side blocks or by increasing the fore-and-aft thickness of universal cap blocks. (c) Shoring and side blocking can be combined to resist earthquake-type forces. In no case should the amount of shoring used be less than would be required for safe docking. Wale shores should be suitably secured to prevent the shores on one side from falling out when those on the opposite side are compressed. (d) Wale shores are not suited for dockings in which there is considerable clearance between the vessel and dock wall. Shores having excessive length would require either a large number of wale shores or require shores so heavy as to make them difficult to handle. e. Propellers, Rudders, and Projecting Devices. From the time the extremity of the vessel first to enter the drydock crosses the sill of the dock going in and until that extremity crosses the still going out, the propellers must not be turned over unless authorized by the U.S. Army marine inspector. On those vessels being moved entirely by tugs and lines from shore, the propellers must not be rotated and the rudder must be kept amidships. Operating devices that project below the keel are to be kept, if possible, in the retracted position. f. Shifting of Weights. No weight or any liquid, such as fuel, water, and oil, will be shifted, added, or removed from the vessel AGO 5244A while the vessel is in drydock unless specifically authorized. When permission is given to shift weight, the responsibility for keeping an accurate record of the amount and location of the change of weight rests with the commanding officer. The responsibility for keeping an accurate record of weight changes accomplished by the shipyard in conjunction with the drydock work rests with the shipyard. Weight should be so disposed at the time of flooding for undocking as to insure having the vessel lift from the blocks without taking an undue list. g. List and Trim. A vessel entering drydock should be without list and without excessive trim. Trim in excess of the allowable figure based on permissible block pressures or of the allowable figure based on transverse stability can make the docking operation hazardous. If examination of the vessel by the shipyard representatives is not possible before docking, the commanding officer will inform the shipyard of the draft forward and aft, in reference to the keel, and the amount of list. This information will be furnished sufficiently in advance of the time of dock~ng to permit safe docking arrangements to be made without delaying the docking. h. Correcting Ship's List. (1) It is difficult to dock a vessel which has a list. If a vessel has a list, every effort should be made to remove it before docking. A vessel can be docked with a very small list if the proper centerline correction is made while lining up the vessel over the blocks. While list or heel of a vessel is practically always caused by nonuniform loading, the docking officer should first definitely determine the cause of the list, and ascertain that it is not due to negative stability. (2) Correction of list due to nonuniform loading is accomplished either by shifting fuel or water between port and starboard tanks or by placement of small heeling weights on the main deck. For large vessels or large angles of heel on smaller vessels, the shifting of liquids will be the most practical method. When transferring liquids to reduce list, it is advisable to shift liquid from tanks already slack to tanks already partially full. i. Use of Wale Shores and Masthead Tackles. Wale shores and masthead tackles are sometimes used to remove list when landing the vessel. These methods are not recommended for normal use; however, they can, on occasion, be useful for special circumstances. A brief description of each follows. (1) Wale shores. This method consists of driving up the shores on the down side successively from the point of landing immediately after the vessel has landed full length along the keel. Shores are kept hand-taut on the up side. If the ship cannot be landed all along before righting, the job is more difficult because of the tendency of the shores to push the vessel sideways at the unlanded end. Undei· these conditions, it is necessary to use one or more shores as preventers as near as practicable to the unlanded end and on the side of the vessel opposite the righting shore. (2) Masthead tackles. The tackle is secured to a masthead and the free end led normally to the vessel to a snatch block, and thence to a capstan ashore. The vessel is landed before taking a strain, and pumps are slowed or stopped during the righting operation~ The higher the tackle is placed, the less pull necessary, the less is its horizontal component which tends to breast the vessel sideways, and the greater is its vertical component which tends to hold the vessel down on the blocks. Shores should always be used with masthead tackles to prevent the vessel from moving sideways. j. Transverse Stability During Docking. (1) Consideration must be given to the stability of a vessel while the water is being pumped out of the drydock, particularly if the vessel has appreciable trim. This consideration is necessary because at reaching a draft before the vessel lands completely, fore and aft, the vessel can take an objectionable list and necessitate being refloated. In cases where stabHity is questionable, the most critical condition will occur when the vessel just lands fore and aft. The reason for this is that the vessel cannot be hauled in to bear against the dock blocks. The docking officer will ascertain if the vessel to be drydocked has adequate stability prior to pumping down. k. Docking with Trim. When it is necessary or desirable to dock a vessel with appreciable trim, the docking officer must insure that both the total load on the aft-keel block or knuckle block and the maximum unit stress at the after end of the knuckle block remain within permissible limits. l. CorrecUng a Vessel's Trim. It is frequently necessary to reduce a vessels trim prior to entering drydock. This can usually be accomplished by the transfer of liquids in inner bottom or wing tanks or, in some instances, by shifting of weights or cargo aboard the vessel. If the vessel is quite small, it can be feasible to trim the vessel by placing small trimming weights .on the dock. m. Clearance Over the Blocks. At the scheduled docking time, the docking officer will determine that there is ample water over the blocks to permit the vessel to enter the drydock and to prevent the vessel landing prematurely due to a rapidly falling tide. This determination will be made by calculating or having calculated to his satisfaction the height of the tide with respect to the height of the tops of the drydock blocks and the deep draft of the vessel. In addition, consideration should be given to the maximum height of the keel blocks and side blocks, as well as to the hull projections, in determining adequate safe clearance over the blocks. n. Dock Block Settings Check. Before flooding, the docking officer will check the blocks, paying particular attention to the following factors: ( 1) Location of first or after keel block. (2) Location of the square marks on the coping of the dock for placing the stem and stern of the vessel preparatory to landing. AGO 5244A (3) Location of fore and aft centering markers. ( 4) Side clearance of the vessel. ( 5) Rudder and propeller clearance above the dock floor and space for shaft removal. (6) Offsets from centerline or set keel blocks and bilge blocks. (7) Height of reference plane from which block heights are measured; height of set bilge blocks; and keel blocks, if keel has excessive departure from level plane. (8) Location and heights of hauling bilge blocks, if used. (9) Special blocking arrangements for hull projections, hull openings, and planned underwater work. (10) Crane clearances. ( 11) Removal of unnecessary blocks. (12) Level or keel blocks for length of keel of vessel to insure that there are no unduly high blocks. ( 13) Reference plane for blocks with a transit in the case of docks with irregular floors or downward slope. o. Flooding Dock and Removing Caisson. ( 1) The docking officer will be present at the time the dock is flooded and will remain at the dock until all blocks are well covered to insure that no blocks come adrift or are misplaced. (2) The caisson will not be deballasted or removed until the water level is the same on both sides. p. Handling of Lines. The docking officer will direct the handling of lines to insure the safe entrance of the vessel into the dock. In general, breast lines and spring lines will not be led on the dock ahead of their position on the vessel but will be kept abreast or abaft. When two spring lines lead from one bow or quarter, one should lead over a bollard or cleat while the other is being shifted. Breast lines should be shifted, on either side, one at a time, while all other lines are led over bollards or cleats. In docking small vessels, considerable latitude is allowed in this respect, subject to the vessel being kept fully under control. AGO 6244A q. Pumping Down. (1) The docking officer will center the vessel, using centering bobs, si'ghting battens, and other appropriate equipment. The vessel will be kept centered during the pumping down operation. (2) He will note the drafts on the vessel and observe that the vessel lands at the proper points with respect to the draft. (3) The docking officer will stop the drydock pumps and, if necessary, reflood in case of the following: (a) The vessel takes an undue list when landing. (b) The vessel lands before the water has dropped to the proper depth. (c) A shore buckles on landing. ( 4) He will exercise care that positioning lines are not parted when the vessel is about to land. r. Precautions for Vessels in Drydock. ( 1) Repairs undertaken on outboard valves will be completed expeditiously, in order that the valves will remain disassembled the shortest time practicable. (2) While in dock, openings in the hull caused by disassembled outboard valves will be closed temporarily at the close of working hours, by replacing the valve bonnets and bolting bonnet securely in place or by blank/ flanging the openings. A report that all valves have been closed and bonnets secured will then be made to the commanding officer and entered in the engine room log. (3) Before a dock is flooded, all outboard valves will be carefully inspected to verify that they are properly secured. The result of this inspection will be reported to the commanding officer and entered in the engine room log and the material history record. While flooding a dock, continuous inspection of outboard valves will be made until the vessel is afloat and all valves are under a normal working head of water. (4) No fuel oil, gasoline, or other flammable liquid will be pumped or drained into the dock. When it is necessary for a vessel in dock to discharge any liquid from a gasoline tank, fuel oil tank, or other flammable liquid tank, such liquid will be discharged only under yard supervision into a special container, even though it is estimated that the tank contains no gasoline, fuel oil, or other flammable liquid. If a tank is found to contain flammable liquid, the yard will take necessary precautions. (5) No water, fresh or salt, will be drained into the drydock unless approval has been given by the docking officer or his assistant. Section Ill. HAUL OUT PROCEDURES 112. Marine Railway Handling Keel blocks and chine chocks can be used on a marine railway for vessel haul out. Float the vessel over prepared chocks and blocks so that they line up with proper reference points on the vessel. See appendix III for applicable docking plan. These docking plans should be used to insure an even distribution of weight on the entire keel section and bulkhead reference points. 113. Floating Drydock If a floating drydock is available, arrange the cradle on the drydock and then submerge the cradle and drydock into the water deep enough so that the vessel can be placed on it without damaging propellers or rudders. When the vessel is in the proper position on the cradle, pump the water from the drydock tanks and allow the dock to float both cradle and vessel out of the water. If a cradle is not available for use on ·the floating dock, use applicable docking plan. 114. Lift-Handling (Crane or Derrick) When lift-handling equipment is available, care must be taken to insure that the crane or derrick is of ample capacity to handle the vessel and cradle at the necessary operating radius of the crane or derrick. Vessels or craft over 50 feet in length can be lifted with sui·table slings. However, wooden craft require the use of spreaders in conjunction with the slings to prevent undue stress on the sides of the hull. Vessels under 50 feet in length can be lifted on suitable slings. Wooden cradles will be ballasted sufficiently to allow them to sink when placed in the water, thus allowing the vessel to be positioned into its cradle. It is the responsibility of the accountable officer to determine that lifting crane or derrick is of ample capacity and that all gear is in serviceable condition before the vessel is hauled out. All lifting gear should be designed with a safety factor of six. 115. Use of Beaching and Tide If neither a marine railway nor floating drydock is available, the vessel can be beached in a locality with sufficient rise and fall of tide. If a cradle is available, place it in shallow water at high tide so that just enough water is over it to float the vessel onto the cradle. When the tide recedes, the necessary below-waterline repairs can be made. The vessel can then be floated off the cradle at the next high tide. Caution: The use of a cradle on a beach is dangerous to personnel and equipment. Tide, wind, sea condition, and beach gradient will affect haul out operations and must be carefully considered. Insure that the hull will not slip out of the cradle. Section IV. CLEANING AND INSPECTION 116. Cleaning After Haul Out Immediately upon removal from the water, thoroughly wash down and clean the bottom of the vessel, using suitable brushes, ·scrapers, and an adequate supply of fresh water. Remove all underwater growth, barnacles, rust, scale, and loose paint. Marine growth should be removed from the bottom of the vessel before it dries and hardens. Clean all below-waterline through-hull fittings, connections, and screens AGO 6244A Figure 105. Typical buildup of marine growth. or grills. Typical buildup of marine growth on a picket boat is shown in figure 105. 117. Inspection After Haul Out After haul out and bottom wash down, an inspection of the hull must be performed to determine the condition and repairs required. a. Steel Hull. When inspecting steel hulls, check for the following: ( 1) Broken, buckled, torn, or punctured plates. (2) Damaged riveted or welded seams. (3) Damage to through-hull fittings. (4) Damage to supporting structure (if the hull has received major damage). Mark all areas to be repaired with chalk or crayon. AGO 6244A b. Wood Hull. An inspection of wood hulls should include the following: (1) Check all seams for possible loose calking and rotted plank edges as well as loss of seam composition. Mark bad locations with suitable chalk or crayon. (2) Check all butt blocks as well as butt seams and fastenings, making certain that there is no loose calking and that the plank ends and butt blocks are sound and well fastened. (3) Check chines for possible splitting as well as for soundness, making certain fastenings are secure and seam calking is in good condition. ( 4) Check keel and garboard strake thoroughly for soundness, making cer tain that borers have not been bored (1) Bruised spots, cracks, and broken or too deeply, causing loss in structural exposed fibers. strength or watertightness. Check (2) Weak seams. seams for rot and loose calking or (3) Damage to through-hull fittings. seam decomposition. c. Plastic Hull. When inspecting plastic or (4) Weakness or damage to all supporting fiberglass hulls, check for the following: structural members. Section V. STORAGE PROCEDURES 118. General Storage information in this manual is general and is intended to be used as a guide. Details covering the processing of vessels and related equipment for standby and long term storage are outlined in TB TC 9. Limited storage processing procedures are listed in the organizational maintenance manual of each vessel by design number. When practical, vessels, should be placed in dry storage, in lieu of wet storage. Consideration for dry storage will be based on the availability of suitable storage space and necessary lift-handling equipment. 119. Wet Storage a. Location. A wet storage location should be sheltered from excessive currents, waves, ground swells, and high winds. Permanent moorings should be placed where the bottom affords good holding ground and where the vessel will have room to swing. (1) Depth of water. Water must be of sufficient depth to insure water under the keel at all times. Due allowance should be made for the maximum depth of wave troughs at dead low tide. The bottom should be searched for rocks, old piling, or other objects which might be present and cause damage to the hull. (2) Marine growths and animals. Wooden vessels, unless metal sheathed or specially painted, should not be placed in wet storage in waters infested by the teredo or other boring worms. Waters above 306 latitude are less apt to be dangerous; however, teredo is prevalent on the Pacific Coast up to Alaska. Polluted waters of harbors generally support less marine growth than clear, clean waters. Industrial pollution causes other deteriorative conditions, however. (3) Ice conditions. Vessels must not be stored in waters which will freeze over unless specially protected for such conditions. ( 4) Sun and heat. Wooden vessels stored in the sun or in hot, dry climates are apt to shrink badly by drying out excessively. Shrinkage should be counteracted by periodically wetting down decks, superstructure, and topsides. b. Mooring Lines and Chafing Gear. The fol lowing is for the general guidance of operating activities, as complete coverage of all possible conditions is impractical. (1) Permanent moorings. Permanent moorings should consist of a mushroom anchor or a concrete monolith of sufficient weight and with suitable chain, pennant, and gear. Sizes of anchors, chains, and gears recommended for permanent moorings, are listed in table VIII. Sizes listed are to be considered minimum for the vessels covered. Vessels longer than 85 feet in over-all length will not be stored at permanent moorings except under special circumstances and with special equipment. Permanent moorings will be raised at least once each year for inspection and necessary repairs. Kedge, stockless, or Navy type anchors should not be used for permanent moorings. A typical arrangement of a permanent mooring is shown in figure 106. AGO 5244A EYE SPLICE OVER KING POST OR CLEAT NOTES: 1. BE SURE KING POST OR CLEAT IS STRONG ENOUGH TO TAKE MOORING STRAINS. BRACE EXISTING GEAR OR INSTALL NEW GEAR AS NECESSARY. 2. ONLY WIRE ROPE WILL BE USED IN TROPICAL WATERS AS BORERS ATTACK THE FIBER ROPE. 3. PICKUP TACKLE SHOULD BE LONG ENOUGH TO ALLOW STOWING BUOY ON DECK OF VESSEL. 4. L-LENGTH MUST BE AT LEAST FIVE TIMES THE GREATEST DEPTH OF WATER. Figure 106. Typical arrangement of permanent mooring. Table VIII. Recommended Mooring Gear by Size Chain size Pennant size Anchor ' (in.) Shackle Fiber (in.) V esse! over-all length weight size circumference (ft) (!b) (in.) (in.) Wire dia.rneter Heavy Light (in.) For motor craft of light construction 25 and under -------------------225 % % % 3% %26 to 35 ------------------------300 1 %e %e 4 %636 to 45 ------------------------400 1 % lh 4% %46 to 55 ------------------------500 1 %e %6 5 %e56 to 65 ------------------------600 1 % % 6% % For working craft, towing craft 36 to 45 ------------------------600 11,4 % % 6% %46 to 55 ------------------------750 11,4 % % 8 %56 to 65 ------------------------900 1% 1 1 9 166 to 75 ------------------------1,050 1% 1 1 9 176 to 85 ------------------------1,200 2 1% 1% 11 1% Notes. 1. Weights of anchors tabulated are for mushroom anchors only. 2. Use wire rope where possible for pennants for vessels in excea s of 56 feet in length. AGO 5244A 131 (2) Dockside mooring lines. Lines for dockside moorings should be arranged as shown in figure 107. Mooring lines will be of sufficient length to allow the vessel to rise and fall with the tide. Where the rise and fall of the tide is excessive, special arrangements can be necessary. Recommended sizes of SMALL VESSELS mooring lines are listed in table IX. (TO 45 FEET OVERALL LENGTH) Table IX. Recommended Sizes of Mooring Lines Size of vessel Under 45-64 65-84 85-99 100-134 135-169 170-200 45 Bow and 3 0 4 5 6 7 8 9 stern lines. Spring lines 2% 3 4 4% 5 5% 6 Notes. SMALL VESSELS 1. Size of vessels, over-all length in feet. (TO 65 FEET OVERALL LENGTH) 2. Minimum fiber rope sizes for mooring vessels, size of rope circumference in inches. (3) Chafing gear. Vessels at individual moorings require little chafing gear. Metal mooring buoys can be fitted with rope bumpers to prevent scarring hulls of vessels. Vessels moored at dock side or in banks at dockside must be carefully protected by chafing gear. Log camels and fenders or bumpers of woven fiber rope, old fire hose, hawLARGE VESSELS (TO 200 FEET OVERALL LENGTH) sers, woven cans, cork-filled canvas, rubber tires, cork life preservers, and saplings can be utilized. No spikes, Figure 107. Recommended use of dockside tie rods, timbers, or similar objects mooring lines. which might damage the vessel should protrude from the dockside. New or and bottom inspection. While in dryserviceable fiber rope should not be dock, the following will be accompused for chafing gear. Log camels are lished:heavy timbers floated between the ves (a) Inspect inside and outside of entiresel and pier. They are fastened so that underwater body. Correct any structhey can rise and fall with the tide. tural deficiencies, such as broken or (4) Vermin guards. Rat guards, wireworn planking or deteriorated wastmesh screening, and other shields or ing plates.devices to prevent entry of rodents (b) Renew all zinc plates.and other vermin will be used where (c) Clean and close all sea chests, seaeffective protection can be accomvalves, strainers, scupper drains, plished. overboards, or openings which pen c. Prepqration of Hull for Wet Storage. etrate hull below main deck. (d) Open, inspect, repack if necessary, (1) Drydocking. All vessels will be dryand then tighten propeller shaft docked prior to being placed in wet storage. Refer to applicable technical stuffing box. (e) Clean underwater body thoroughlymanual for required public haul out AGO 6244A 132 of all marine growth, scale, rust, or loose paint. (f) Inspect and calk seams of wooden vessels. (g) Apply at least one coat of antifouling paint on bottom of wooden vessels without metal sheathing. Do not paint vessels completely sheathed with copper. Inspect copper to insure that no openings exist that would allow entry of marine growth or animals. (h) Note that the extent of treatment of steel vessels to be placed in extended wet storage is governed by the actual condition of the vessel, date of last haul out and painting, and the projected period in storage in relation to the next scheduled haul out. The following will be accomplished, as specified in TB 7 4693-4. 1. Surfaces of the vessel to be painted must be thoroughly cleaned. Remove all loose and blistered paint, deteriorated areas of old paint, rust, corrosion products, oil, grease, dirt, fouling organisms, and other surface contaminants prior to painting. 2. Spot painting or touch-up will be performed on vessels when less than 50 percent of the paint surface or system of a major area has deteriorated leaving the underlying surface unprotected. 3. Major painting of vessels will be accomplished when the surface paint or paint system has deteriorated more than 50 percent which leaves the underlying surface unprotected. When several separate damaged areas add up to more than 50 percent of the total surface area, major painting will be required. 4. Treat propellers, exposed shafting, struts, rudders, pintles, starks, and other appendages of ferrous metal as outlined in applicable technical manual. (2) Removals and cleaning. Remove and store separately all portable equipment, spare parts, tools, deck gear, in- AGO 5244A struments, utensils, supplies, and stores, except fire .. fighting equipment. Clean interior of vessel. Use insecticides where required. Remove all scrap, dirt; and foreign matter from all parts of the vessel. Thoroughly clean bilges and free all limbers and scuppers. Thoroughly clean, neutralize, and gas-free the bilges if fuel or other flammable liquids have been allowed to accumulate. Remove all scale, rust, and loose paint. (3) Tanks and bunkers. (a) Empty, clean, and gas-free all tanks, paint lockers, or other containers of fuel or flammable liquids or gases, including liquid barges. Test to insure safety. When found unsafe remove such liquids from the vessel. (b) Remove all solid fuels from vessel. clean and wash down all bunkers or other containers. ( 4) Piping systems. Drain all piping systems and those parts of machinery or equipment to which they are attached, except the hydraulic system of the telemotor and refrigerant piping. Do not leave water or other liquid in any fixture or appliance which would promote corrosion or which might freeze. If it is impossible to drain any system completely, add antifreeze compound to the remaining water to give adequate protection for expected temperature. Tightly close all valves and cocks. ( 5) Drainage. Insure that all parts of the vessel will drain properly into the bilges or overboard. Provide scuppers, limbers, or other means of drainage for low spots, pockets, or depressions as necessary. ( 6) Ventilation. The importance of proper ventilation of a vessel in storage cannot be overemphasized. Proper ventilation will do more to prevent corrosion in steel. vessels and rot in wooden vessels, than any other factor. The following procedure will be utilized for ventilation: (a) Secure in open position all interior doors, hatches, manholes, scuttles, and openings of any type to insure free circulation of air to every compartment in the vessel. Lift all floor boards or removable floor plates to insure proper ventilation of bilges. No compartment or pocket of the vessel should be isolated. (b) Test all doors, hatches, manholes, scuttles, hinged ports, and ventilators leading from interior to exterior for watertightness. Leave openings as necessary to insure that every compartment of the vessel is adequately vented to the outside air, either directly or through another compartment. Arrange such openings so that rain or spray will not enter. Use shields, covers, or batHes on large vessels. Covers constructed of a ridge pole and slats covered wtih asbestos roofing can be constructed over openings or over an entire small vessel. Such covers allow ventilation and still protect the vessel from rain, snow, and sun. Do not sacrifice ventilation to prevent entry of rain or snow. Rain or snow is preferable to poor ventilation, provided no machinery, equipment, or upholstery is allowed to get wet. (7) Pumping arrangements. Make suitable arrangements to pump the vessel's bilges. Insure that such arrangements will be of sufficient capacity to keep the vessel afloat in case of damage to the hull and will have a capacity no less than that of the main bilge pump of the vessel. (8) Preparation and maintenance of machinery and equipment. Instructions for preparation and maintenance of vessels and related machinery and equipment for standby and long term storage are outlined in TB TC 9. Limited storage processing instructions for specific floating craft and amphibians are contained in the organizational maintenance manual for the applicable floating equipment. When processing equipment and equipment for storage, the following basic principles should be used as a guide: (a) Finished surface of ferrous metal invaribly require protection. (b) Exposed threaded fastenings and pipe fittings should always be processed to prevent freezing. (c) Corrosion-preventive compound should be used for protection against corrosion. (d) Fuels contain corrosive substance and should be removed. (e) Petroleum products rot rubber and deteriorate electrical insulation. (f) Nameplates, finished surfaces, electrical contacts, threaded fastenings, valve stems, match markings, assembly markings, and parts which move past other parts with close clearances should be cleaned and protected with proper preservatives. (g) Mating surfaces, which move in relation to each other and which cannot be fully coated with a preservative without disassembly, should be lubricated with a rust-inhibiting oil .or grease and moved periodically to work the lubricant over all parts of the surfaces. d. Hazards and Precautions. Principal hazards to vessels in storage and the precautions to be taken are outlined below. (1) Fire. Clean vessel thoroughly and dispose of paper, rags, and waste. Clean tanks and bunkers. Maintain adequate fire extinguishers, which will be filled, inspected, recharged periodically, and ready for use. Insure that adequate shore-mounted firefighting equipment is available. Do not allow smoking, open flame, and other igniting sources in the vicinity of stored vessels. ( 2) Sinking. Secure moorings in deep water free from obstructions. Close valves and sea connections. Insure that there is no leakage past propeller shaft gland. Make sure that adequate 134 .!.GO 6244A bilge pumping facilities are available. Insure that mooring tackle, king posts, cleats, or bollards on vesel and pier are adequate. (3) Corrosion and rot. Insure that adequate ventilation, proper painting, and adequate drainage are provided. ( 4) Pilferage. Do not allow unauthorized personnel on or near vessels in storage. e. Maintenances While in Wet Storage. Activities that maintain vessels in wet storage will arrange to get advance warning of inclement weather from U. S. Coast Guard, Navy, or weather bureau stations. (1) Nonscheduled inspections. Inspect vessel in wet storage prior to expected inclement weather. Insure adequacy and soundness of moorings, mooring lines, cleats, king posts, and chafing gear. Apply additional tackle if winds in excess of 50 mph are expected. Close openings not needed for minimum ventilation requirements. Check and make fast all gear, and check antifreeze. Nonscheduled, spot check, or informal inspections should be conducted periodically to insure that applied preservatives and other processing methods are adequately protecting vessel in storage. All deficiencies found should be recorded and corrective action taken immediately. Reports and recommendations should be submitted as required. (2) Scheduled inspections. In storage, maintenance operations will normally be based on scheduled or cyclic inspections. Cyclic inspections should be planned with enough detail and programmed to accomplish desired results of maintenance. Discrepancies found during cyclic inspections normally require special recording of conditions found, corrective action taken, and submission of formal reports. The type and scope of inspection must be suitable to the particular type of vessel, storage facilities, AGO 5244A and system of preservation used. The most efficient method of determining the condition of a vessel in storage is by activation. Different methods of preservation do not preserve the same over long periods. When inspecting by the activation method, select a sample vessel for test by considering the usage factor of the type of vessel, the method of preservation, and the length of storage. All inspections by trial activation will have to be coordinated with the Transportation Supply and Maintenance Command by the specific storage installation. 120. Dry Storage a. Location. When the dry storage method is to be used to store vessels, careful consideration should be given to the selection of an adequate location. Available space and lift handling equipment are mandatory requirements. All vessels should be stored on firm, level ground. Precautions should be taken to prevent settling of the vessel. When vessels are stored on sloping ground, they should be blocked so that their waterlines are horizontal to insure proper drainage. Storage locations should be sheltered from high winds as much as possible. ( 1) Sun and heat. The effect of sun and intense heat is not as harmful to steel vessels as it is to wooden vessels. Wooden vessels must be protected from intense sun and the glare reflected from hard, dry ground. The best location for small craft storage is under sheds, trees, or improvised shelters, and preferably where there is thick grass or weeds. Weeds or grass should not be destroyed, but should be encouraged up to a height of approximately 12 inches. Foliage should not be allowed to engulf vessels or to become high or thick enough to create a fire hazard during dry weather. (2) Firefighting equipment. Firefighting equipment inust be available to locations selected. (3) Wetting .down wooden vessels. Planking and timbers of wooden vessels will DOUBLE WEDGED SHORE KEEL BLOCKS STEEL SHIMS KEEL BILGE BLOCKS SECTIONS OF BROAD BEAM FLAT BOTTOM VESSEL BLOCKS CUT TO FIT CURVE OF BILGE THREADED EYEBOLT THRU STRONGBACK AND CONNECTED BY WIRE ROPE TO SIMILAR GEAR ON OPPOSITE SIDE KEEL BLOCKS MIDSHIP AND AFTER SECTIONS OF NORMAL VESSEL FORWARD V-SHAPED SECTION OF SMALL VESSEL Figure 108. Typical blocking of vessels. shrink badly upon drying out if stored dry for long periods. Hulls should be floated for several days, and topsides, decks, and superstructure should be wetted down annually. If signs of shrinkage appear between these annual treatments, the entire vessel should be hosed down to allow the wood to absorb water. Water can b~ retained in small quantities inside the hull for brief periods to allow swelling, provided care is exercised not to strain the hull due to weight of the water. b. Blocking and Cradles. The basic principles of proper blocking of vessels for storage AGO 6244A include the design and application of supporting structures (figure 108). (1) Structural members of vessels are designed to take the load of the vessel afloat. The weight of the vessel, including its machinery and equipment, is supported by water pressure on the entire underwater portion of the vessel. The load is widely distributed, and the strain to which any member is subjected is relatively small. Proper blocking can give support similar to that given in the floating position. Many well-distributed supports are preferred to fewer, stronger supports which allow concentrated loads on parts of the vessel. (2) Hauling cradles, built for specific vessels, are usually intended to support the vessel during the hauling operation only. Vessels which are to be stored in such cradles should be adequately blocked in addition to the support furnished by the cradle. Blocking should consist of keel blocks, bilge blocks, and shores. (3) Docking plans, profiles, line drawings and section drawings of affected vessel will be utilized in planning and preparing blocking arrangements for dry storage of vessels. (4) Longitudinal distribution of blocking should be such that it supports all parts of the vessel. Supports should be spaced more closely under those parts of the vessel in which heavy weights are installed. Main engines, boilers, generators, and masts are examples of such weights. Care should be exercised in placing and shimming keel blocks to insure support all along the keel. Keel blocks should be arranged so that the waterline of the vessel is hori~ontal. Block all long, unsupported spans or overhangs. The line of the keel should be sighted and measured to insure straightness or proper curvature according to the vessel docking plans. ( 5) The decks of the vessels must be shored and braced beneath heavy AGO 6244A equipment such as large winches and towing J:mgineR. Such loads will be transrnit.t~d through suitable supports to structural members of the ship which are, in turn, adequately braceit by keel or bilge blocks immediately below such supports. ( 6) Jacks and wedges should be used freely in blocking vessels, but care should be exercised to avoid straining any part of the vessel by jacking or wedging. (7) Rudders of all large vessels and propellers and shafting of large twin screw vessels must be supported. c. P'reparation of Hull for Dry Storage. Use procedures recommended for preparation of hull for wet storage (para 119c), with the following additions and exceptions: (1) Paint or touch up bottoms of wooden vessels with antifouling paint only to the ext_!!nt. that no bare wood is left unprotected. Paint bottoms of steel vessels with one coat of anti-corrosive paint. (2) Leave sea valves open to promote drainage. (3) Assemble propeller shaft stuffing boxes loosely after preservative processing. ( 4) Remove existing hull drain plugs or drill holes not less than %, inch nor more than 11;2 inches in diameter through hull at lowest point or points in each watertight compartment. On steel hulls, weld a doubler plate of suitable thickness to outside of hull at location of proposed hole. Drill hole through hull and doubler, and tap from inside to receive pipe plug. Ream finished holes in carvel-planked wooden hulls to receive a softwood plug. Do not drill holes in clinker-built vessels or in. vessels with plywood hulls. Other arrangements must be made for removing accumulated water from these vessels. From interior, mark all holes permanently and prominently to preclude possibility of launching vessel without plugging holes. Shelter small vessels with a cover consisting of a ridge pole and slats covered with canvas or roofing material. Do not allow such covers to interfere with ventilation. Similar covers can be constructed over large openings or other parts of larger vessels susceptible to weather. Open craft, such as small lift boats, can be stored bottom side up. (5) Note that preparation and maintenance of machinery and related equipment on vessels being processed for dry storage will normally be the same as described for vessels in wet storage (para 119c (8)). d. Maintenance While in Dry Storage. Activities maintaining vessels in open, dry storage will arrange to get advance warning of inclement weather from U. S. Coast Guard, Navy, or weather bureau stations. (1) Nonscheduled inspections. Inspect vessels in dry storage prior to expected inclement weather to insure soundness of blocking and shores, adequacy of antifreeze precautions, proper covers and lashings, and closure of apertures normally left open. Winds of hurricanes force can exert enough pressure on the side of a vessel to cause wedges under shores to drop out, possibly causing the vessel to turn over on its blocking. Immediately after inclement weather, inspect vessels for soundness of blocking and shores, condition of covers and lashing, and evidence of freezing. Remove covers over openings to allow complete airing of vessel. Check vessels for accumulations of undrained water or snow. (2) Scheduled inspections. During periodic inspections, make a careful check of blocking and shores. Sight and measure keel line to insure proper alinement of keel blocks and freedom from settling. Check covers for adequacy of protection, soundness of lashings, and proper ventilation. Covers and all openings normally closed must be opened for several hours at least once a month to thoroughly air the vessel. Check vessel for evidence of shrinkage, rot, corrosion, and poor ventilation. Check condition of paint, protective films, seals, and wrappings. Wet down vessels showing signs of shrinkage. Include necessary repainting and also reprocessing of machinery and equipment in semiannual inspections. Semiannual overhauls should be performed in the fall and spring so that differences in arrangements for summer and winter storage can be accomplished. 121. Prevention of Electrolytic Corrosion to Stored Vessels Electrolytic corrosion is a problem to vessels in storage as well as to those in active use. The degree of electrolytic corrosion to stored vessels will depend primarily upon the type of storage, wet or dry. Vessels in wet storage will be affected differently in salt water as compared to fresh water. Salt water is a stronger electrolyte than fresh water and causes the natural electric-current flow through the salt water to be much stronger. Zinc wasting plates, installed on vessels to combat electrolytic corrosion, must be inspected and replaced when the plates have less than 50 percent of original plate remaining. The inspection of the zinc wasting plates is accomplished prior to placing vessels in storage, during the storage period, and prior to reactivation of the vessels. Wasting plates installed on vessels in prolonged periods of dry storage should also be inspected, as moisture in the air and the accumulation of rain water within the vessel will cause electrolytic corrosive action. AGO 5244A CHAPTER 4 WOOD HULL REPAIR Section I. GENERAL INFORMATION 122. General a. The wood hull consists of structural framework to which the planks are fastened. Harbor craft are designed and constructed to withstand the pressures and strains encountered when fully loaded and in .the heaviest seas. The interior of the vessel is divided by the bulkheads and decks into watertight compartments. A vessel deck usually has fore-and-aft curvature called SHEER and athwartship curvature called CAMBER. Sheer provides reserve buoyance for improved riding qualities and normally results in a drier and safer vessel. Camber allows water to drain to the sides of the vessel where it is led overboard through the scupper drains. b. When referring to vessel measurements, the length over-all (LOA) is the total length from the foremost to the aftermost points of the h'ull. The length between perpendiculars (LBP) is the distance between the forward and the after perpendiculars. The breadth is the greatest breadth between the outside surfaces of the shell plating or planking. Freeboard of a vessel is the distance in feet and inches from the waterline of the vessel to the top of the main deck. The deck line, marked amidships, is a painted reference line drawn through the intersection of the molded line of the deck beams and the molded line of the frame. The draft of a vessel is the vertical distance from the waterline to the lowest point of the vessel bottom. c. During the service life of a wood hull ves sel, every effort should be made to provide thorough ventilation and drainage and to prevent water leakage. All ventilation terminals should be kept open and mechanical ventilation systems kept in operation at all times practicable. Sanding of decks and calking of seams must be done carefully to retain the proper camber and to prevent depressions which will allow standing water to accumulate. Hatches and deck plates of wood vessels afloat should be opened in fair weather to supplement air circulation provided by the ventilators. Salt water should be used for washing down the vessel because it has some preservative value. A sponge or chamois lightly soaked in fresh water can be used to remove salt accumulations from bright work, chrome fittings, and windows. A wood preservative solution can be applied to hull areas that were purposely left unpainted. Fenders or rubber tires should always be placed between adjacent vessels tied up at a dock, pier, or boom. d. The use of solvent emulsion is not necessary except in areas where there has been an accumulation of oil, grease, or diesel fuel. Oilsoaked bottom planking cannot be successfully calked or painted; therefore, solvent emulsion is used in cleaning the bilges where oil or grease has accumulated. Varnished surfaces can be refinished by removing old polish with a petroleum solvent followed by soap and water rinsing, drying, and light sanding of the surface with 4-0 sandpaper. Newly varnished surfaces can be protected and maintained by using an oil base polish. 123. Methods of Hull Construction There are four general methods of constructing the three basic forms (para 25) commonly used in modern small harbor craft. These methods are described briefly as follows: a. Carvel. The planks which cover the sides of the vessel lie alongside each other without AGO 5244A overlapping, and the seams are calked. When two layers of planks are used, the layers are separated by canvas or compound. The planks of the inner layer will have the seams staggered from those of the outer planking. b. Clinker or Lap Strake. The planks overlap at their edges in this construction and are fastened to each other as well as to the frames. This type of construction has greater strength than the carve! type because the planks support each other. Nc:r calking is necessary because the planks swell and bind one upon another. c. Diagonal. The planks run diagonally, at about a 45-degree angle, from the keel to the gunwales. The planks are laid in two thicknesses at right angles to each other. This type of construction is very shong and is used chiefly for large vessels carrying heavy loads. d. Plywood. Thin strips of plywood, impregnated with waterproof glue, are diagonally bent over a mandrel or mold to the desired shape. The skin is built up of several layers, then placed in a superheated steam-pressure room where the wood is curved to form a singlepiece hull. Section II. REPAIRING WOOD HULLS 124. General All wood members entering into the repair of wood vessels will be smoothly finished on all sides. Uncalked seams, joints, and faying surfaces must be fair and continuous and will be watertight when assembled with calking (tompound. The outside of the hull must be fair, free from tool marks, and sanded smoothly. Wood members, when assembled in place, will not be subject to stresses beyond their proportional limit as evidenced by any damage to the members. Any frames which show splitting or wrinkling will be removed and replaced. Fastenings will be set snugly but not so tightly as to weaken the material by rupture of the wood fibers adjacent to the fastening. Lead holes will be drilled for all screws and fetter ring nails. Diameter of lead holes will not exceed 70 percent of the root:Qiameter of screws for softwoods and 90 '-Percent for hardwoods. In way of screw .sh~nks, the hole in the material to be fastened will be 100 percent of screw shank diameter. Holes for fetter ring nails will be prebored not to exceed 60 percent of the nail diameter. Maximum depth of lead holes should not exceed 90 percent of the length of the screws. Screws will not be impact-driven. The last 1Js inch of screws is to be hand-turned or can be mechanically set, provided that the machines are equipped with a properly adjusted clutch stop device to prevent over-driving. Bolt holes will be drilled smoothly for a tight fit. During repair, all scraps, shavings, refuse, dirt, and water should be removed frequently. Dutchmen will not be used as fillers for improperly cut materials. 125. Causes For Repair The common causes for repairs to wood hulls are marine borer damage, decay deterioration, and mechanical damage. Hull punctures, splitting, overstress, mooring damage, and dropping the vessel from a crane are examples of mechanical damage. Operating in heavy seas can also cause mechanical damage. Temporary repairs, within the capabilities of the crew, can be undertaken to insure the safety of the vessel until proper repair facilities are available. Marine borer damage is usually obvious upon inspection, and major repairs are generally necessary. This requires drydocking the vessel. Detection of decay deterioration is described in paragraph 61. 126. Hull Inspection Inspection, after the bottom is thoroughly washed down, will include the following: a. Check all seams for possible loose calking and rotted plank edges as well as loss of seam composition. Mark bad locations with suitable chalk or crayon. b. Check all butt blocks, but seams, and fastenings, making certain there is no loose calking and that plank ends and butt blocks are sound and well fastened. c. Check chines for possible splitting and for soundness, making certain fastenings are secure and seam calking is in good condition. d. Check keel and garboard strake thoroughly for soundness, making certain that borers AGO 6244A have not bored too deeply which causes loss in structural strength or water-tightness. :Check seams for rot and loose seam composition and calking. e. Check all planking for cracks, loose fastenings, and bad seams. Check along waterline boot-topping for borers to make sure planking is sound, as this location is very susceptible to borers. f. Check guard rails, making sure that they are sound and that metal banding is in good condition and securely fastened. Inspect for both wet and dry rot. Refer to paragraph 59. g. Check general condition of bilges for water, oil, gasoline, and other debris. h. Check condition of inner frame and hull framing and floors. Check transverse and longitudinal framing for cracks and breaks. Srecial attention should be given to fastenings to insure they are working. i. Check condition of bulkhead and superstructure, including doors, windows, screens, cabinets, planking, and canvas. 127. Materials For Wood Hull Repairs Materials used for repair will be at le~st equal in quality to materials used for constructing the hull. Where it is positively known or obvious that the materials used during. 'construction were deficient, the proper authorities should be informed in order that s:ltisfactory substitutes can be made. Most materials for repair are standard stock items conforming to applicable specifications. Wood characteristics and strengths are listed in table I, chapter 2. Applicable specifications of wood used for wood hulls are as follows: Note. Green lumber will not be used. All lumber, except bending oak, plywood, and lumber for lamination, will be air or kiln dried to a moisture content of 13 ± 3 percent when measured with a resistance-type moisture meter in accorrlance with Military Specification MIL-W-19463. Where solid lumber within the foregoing moisture content limitations cannot be obtained, laminated material will be used. For bending oak, plywood, and lumber for laminating, the applicable specification will govern the allowable moisture content. a. Mahogany will conform to Class PD, Military Specification Milr-lr-2549. b. Solid white oak will conform to Class A, Grade 1 of Military Specification Milr-lr-2037, AGO 6244A except that splits, shakes, sapwood, and wane will not be permitted in the finished member. Laminated white oak confronting to Military Specification Milr-W-001515, Grade B, Class 2, is permitted as an alternate to solid oak, c. Bending oak shall be Grade I or II, as applicable, in accordance with Military Sp~~ification MIL-lr-2037. Sapwood will not be permitted in finished member. Bending oak stock can be laminated and steambent or laminated to shape in accordance with Military Specification Milr-W-001515. The grade of laminations will be Grade A, Class 1 or better, except that when installed, no sapwood will appear at the surface faying with the hull planking. d. Laminated white oak members will comply with Military Specification Milr-W-001515, grade B, class 1 or better. e. Laminated Douglas fir members will comply with Military Specification Milr-W-2038, grade B, class I or better. f. Solid Douglas fir lumber will conform to the following grades of West Coast Lumbermen's Association (W. C. L. A.), rs applic?.ble. Laminated Douglas fir, grade B, class 2 or better, in accordance with Military Specification Milr-W -2038, is permitted as an alternate to solid Douglas fir. ( 1) Solid Douglas fir under 2 inches in thickness will conform to paragraph 151-b of W. C. L. A. 1956 Grading and Dressing Rules, except that splits and sapwood will not be permitted in the finished member. (2) Solid Douglas fir to 4 inches in thickness will conform to paragraph 123-a of W. C. L. A. 1956 Grading and Dressing Rules, except that splits, sapwood, and wane will not be permitted in the finished member. (3) Solid Douglas fir over 4 inches in thickness will conform to paragraph 123-a of W. C. L. A. 1956 Grading and Dressing Rules, except that splits, sapwood, and wane will not be permitted in the finished member. g. Yellow pine will conform to paragraph 290 of the 1956 Standard Grading and Dressing Rules for Southern Pine Lumber. Splits, sapwood, and wane will not be permitted in the finished member. Solid Douglas fir can be considered an alternate if yellow pine is not available. h. Cedar will conform to grade A orB, Military Specification MIL--L--2594. Sapwood will not be admitted in the finished member. i. Spruce will conform to either Sitka, B and Better Industrial Clear in accordance with paragraph 351-b of W. C. L. A. 1956 Grading and Dressing Rules for Eastern Spruce, or B and Better Select, graded according to Northern Pine Manufacturer's Rules. Cedar can be substituted for spruce. j. Cypress will conform to Tank and Boat Stock Grade in accordance with N. H. L. A. Grading Rules. Cedar can be substituted for cypress. k. Fir plywood will be class 1, conforming to Military Specification MIL--P-18066. l. Mahogany plywood will be class 2, conforming to Military Specification MIL--P18066. m. Overlaid plywood will be class 3, conforming to Military Specification MIL--P18066. (1) Wood adhesives for laminated members will be in accordance with Military Specifications MIL-W-2038, as applicable. For scarfs, gussets, and other wood components which require assembly-gluing, the adhesive will be type II, class 2, adhesive, Military Specification MIL--A-22397, which is listed on Qualified Products List-397 to cure at 150°F (66°C) in not less than 6 hours. For this particular application, curing will be acceptable at room temperatures of not less than 75°F (23.9°C). For cementing flotation material to wood and to itself, the adhesives are listed that have been tested and found to be satisfactory. No other adhesive will be used without prior approval. (2) Flotation material will conform to Military Specification MIL--A-16591. (3) Wood reservations will be type A or B in accordance with Military Specification MIL--W-18142. ( 4) Wood bedding compounds will con form to type I or II of Military Specification MIL--S-19653. (5) Sapwood, red oak, and white oak are identified in accordance with Military Specifications MIL--W-19476. 128. Tools For Wood Hull Repair The following tools are required for repairing wood hulls: a. Hammers, Mallets, and Mauls. Two carpenter's hammers are required for repairing wood hulls. Size No. 2 with a 13-ounce head is required for general use and size No. Ph with 16-ounce head is required for heavy driving. The heads should be dropforged steel, tempered and hardened, with curved claws. A riveting hammer with 2112-or %,-pound head is required for riveting and heading over drifts. Because drifts must be driven with a minimum number of heavy blows, a light-weight maul is required. A lignum-vitae mallet should be used with chisels. b. Saws. Crosscut saws for rough work should have 8 or 9 teeth per inch. For finished work where clean edged cuts are necessary for tight joints, 11 teeth per inch are required. At least two crosscut saws and one ripsaw are required. The ripsaw has 5·112 teeth per inch. For areas that cannot be reached with handsaws, a compass saw is used. Compass saws have two interchangeable blades, a 12-inch compass blade and a 10-inch keyhole blade. Compass saws are generally coarse-toothed and make a rough cut. Saws should be filed and set frequently. To prevent binding when sawing a long cut or when sawing hardwood, apply machine oil to each side of the blade. c. Planes. Several types of planes are required for wood hull repairs. A 9-inch smooth plane is needed for general use and a 6-inch block plane is needed for cutting across the grain and trimming off corners. For dressing planking where a true, level edge is required, an 18-inch fore plane or a 21-inch jointer is used. A rabbet plane is frequently required for installation and repairs of the deck and cabin. d. Chisels. A complete set of socket-type chisels and a 112-inch and l-inch gouge are required for cutting and shaping wood. A slick is useful where a plane cannot be used and for AGO 5244A \ Figure 109. Correct way to hold a chisel. shaping and truing up a framing member after it is in place and fastened. It is used similarly to a plane or drawknife. Gouges are useful for cutting clearances or mortises for drift and bolt heads. When using a chisel, take small bites and hold chisel as shown in figure 109. ., e. Boring Tools. The breast drill (fig. 110) and ratchet bit brace are used to hold various kinds of bits and twist drills us·ed in boring and reaming holes. They are also used to remove and install screws, nuts, and bolts. A full set of bits and twist drills, including expansive bits (fig. 110), auger bits, and countersink bits, should be available for wood hull can be determined by inserting desired screw into a twist drill gage. A chart on the gage indicates the correct size of drill for a given tap size. f. Screwdrivers. Screwdrivers are made for loosening or tightening screws or screwhead bolts. It should not be used as a prybar or chisel. A complete set of standard, Phillips, reed and prince, and offset screwdrivers are required for wood hull repairs. A ratchet screwdriver should not be used because if it slips it can scar the surface of the wood. Screwdriver bits in sizes %, %6 , 3/s, and 1;2 inch, which are used in the breast drill and ratchet bit braces, are often used instead of screwdrivers. When using a ratchet bit brace for installing screws, AGO 6244A exercise care to prevent twisting heads off or tearing the threads from the wood. g. Measuring, Scribing and Spiling Tools. These tools consist of line rules, bevels, and pairs of compasses. Steel rules are used for measuring inside to outside and should be 72 inches long. For lofting, framing, and layout work, a steel tape measure, a 24-by 16-inch steel square, and a 12-inch combination square are used. A bevel will be used on almost all wood that goes into a vessel. A sliding T-bevel, with a blade not less than 8 inches, is used. For scribing, spiling, and making templates, a 6-inch carpenter's pencil compass and a pair of 8-inch wing dividers are necessary. h. Clamps. A large number of common Cclamps are needed, depending upon the size of the vessel. C-clamps can be used on any kind of material. A bar-clamp is useful for interior cabinetry, paneling, and doors. The bar-clamp can be either the steel bar or pipe style. Handscrew clamps (fig. 110) should be used on material other than wood. i. Power Tools. Power tools required in wood hull repairs consist of the handsaw, bench saw, jointer, electric handsaw, portable sander, drill, shaper, drill press, jig saw, and wood-turning lathe. The handsaw and jointer are the most useful power tools. j. Miscellaneous Tools. Miscellaneous tools (fig. 110) consist of tools such as nailsets, hacksaws, files, rasps, punches, drawknives, and spoke shaves. These tools are used for shaping and fitting planks, after spiling, finishing inside and outside curves, and rounding off sharp edges. Other common tools can be used in wood hull repair. 129. Fastenings Fastenings for wood hulls consist of screws, nails, bolts, drifts, rivets, and glue. Each type of fastening has a specific use which determines its suitability for the particular repair. Figure 111 illustrates common wood hull fastenings. a. Screws. Screws are the most frequently used fastenings in wood hull construction. Properly used, screws have excellent holding power, will withstand severe conditions or service without loosening, and can be removed BODY CUTTING EDGE PATENTED SCREW MATE WOOD PLUG COUNTERBORE CUTTER EXPANSIVE BIT GALV BOAT NAIL GALV WIRE NAIL ANCHORFAST NAIL D CARRIAGE BOLT LAG BOLT OR SCREW STOVE BOLT MACHINE BOLT Figure 111. Common wood hull fastenings. OVAL HEAD SCREW WITH COUNTERSUNK WA<;HFR Figure 112. Oval head screw. (3) Flat head screws. Flat head screws are used extensively in wood hull construction. To provide maximum benefit as a fastening, the flat head screw must be of the correct size and properly installed. The three basic steps necessary for proper installation are as follows: (a) Bore and countersink. Boring and countersinking are done in four stages: the counterbore, or hole to admit the screw head; the countersink, or chamfered hole to fit the underside of the head; the shank, or body hole; and the pilot, or lead hole for the threaded part. Be sure proper counterbore tool is used and that tool is set for correct depth (fig. 113). When a screw is installed too deep or or too shallow, holding power is lessened. (b) Driving. Use proper size and type screwdriver for screws being in -. 4H 1-1/2 INCHES CORRECT TOO SHALLOW TOO DEEP Figure 113. Installation of flat head screw. BEVELED EDGE Figure 114. Cutting off plug. stalled. Drive screw until head bottoms firmly in countersink. (c) Installing plug. Wood plugs are available ready made, or they can be fabricated from the material being installed. If surface is to be varnished, plug should be selected to match wood being installed, and varnish should be used as an adhesive. For other finishes, use an adhesive of waterproof glue. Dip plug into adhesive, place in hole so grain rubs with surrounding wood, and tap into place with a wood mallet. Allow adhesive to cure, then shave down protruding portion of plug with a large chisel (fig. 114). b. Nails. Four types of nails are used in wood hull construction: galvanized boat nails, galvanized wire nails, galvanized finishing nails, and Monel Anchorfast nails. Of these, only the Monel Anchorfast nail approaches the screw in holding power and durability. (1) Galvanized boat nails. Galvanized boat nails have a rectangular body, a blunt point, and a round or oval head. They are available in lengths of 1 to 6 inches. The primary use of gal- AGO 5244A 145 vanized boat nails is for installation of planking. A lead hole must be drilled before they are driven. (2) Galvanized wire nails. Galvanized wire nails have a limited use in hull construction, usually in framing where a screw or bolt would be impractical or for attaching deck planking that is to be covered with canvas. The head must be set below the surface and covered with trowel cement or white lead. (3) Galvanized finishing nails. Galvanized finishing nails are used in light, interior joinery where great holding strength is not required. They are also used in strip-decking, for edge-fastening between frames, and for blind nailing to deck beams. They are available in lengths from % to 2 inches. (4) Monel Anchorfast nails. Due to great shank strength and the annular serrations pointing backward on the shank, Monel Anchorfast nails have exceptional holding power. Monel is the name of an alloy of copper and nickel, with a strength equal to steel, and is practically immune to corrosion. These nails are available in lengths from 5fs to 3 inches. A lead hole should be drilled and counterbored prior to driving. Drive nail until head is almost flush with surface, then set into counterbore with a spikeset or heavy punch. c. Bolts. Bolts are used extensively in framing and for through-fastening structural members. They are also required to secure ballast keels, to fasten hardware and fittings to the hull, and, in specific instances, to secure planking. (1) Machine bolts. Machine bolts are used primarily for fastening ballast keels. Their composition depends upon the metal used in the ballast casting. With iron, only galvanized iron or steel should be used. Lead keels must have bronze or Monel bolts. Any deviation from these combinations means the immediate start of galvanic corrosion. (2) Stove bolts. Stove bolts of brass, Monel, or bronze have a flat head similar to that of a wood screw. They are used for fastening deck fittings and hardware and, where considerable bend is required, for fastening ends of planking to butt blocks. Holes for stove bolts should be counterbored and plugged, as with flat head screws. (3) Carriage bolts. Carriage bolts are used in framing and in fastening most structural members. They have a crowned head, and a short section under the head is square to prevent the bolt from turning when the nut is set up. They are available in galvanized steel, bronze, and Monel, in diameters from 1,4 to % inch and in lengths up to 20 inches. Washers should always be used under the nuts to secure maximum bearing. Never depend upon the nut to draw the square section under the head into the wood; the bolt should be driven with a hammer until it is well seated. When using galvanized bolts, coat the shank with red lead before insertion, and coat the nut and bolt end, after setting up, with red lead as a rust preventive. ( 4) Lag bolts. Lag bolts are available in galvanized iron, steel, and bronze, in diameters of %, to % inch. Bronze lag are used in fastening stuffing boxes and stern bearings. Galvanized iron lag bolts are used to secure engines to engine beds. Proper drilling is nec essary to obtain maximum holding power from a lag bolt. The length of the shank from the underside of the head to the first thread must be measured, and a hole exactly that depth must be drilled, with the same diameter as the shank. A lead hole approximately seven-eighths the length of the threaded part should be drilled, with a diameter no greater than two-thirds of the shank. The lag bolt should be well lubricated with soft soap or grease before driving. AGO 6244A d. Drifts. This form of fastening is a rod of galvanized wrought iron or steel, cut to the required length and driven into a hole bored slightly less than the diameter of the rod. Drifts are used for fastenings in keel timbers, deadwoods, and all heavy members in the keel assembly of large vessel. They are also used for edge-bolting rudders, centerboards, and planked transoms. Log rails are edge-fastened to clamps or sheer strakes with drifts. Cabin trunks are often edge-bolted to carlins in a similar manner. The term drift can mean one of several things. In general, it is a long fastening. When driven only part way through the timbers, it is essentially a nail or spike. When it is a through-fastening, it is in effect a bolt. All through-fastening drifts are driven with a clench ring under the head, which should be of the same metal and of a size to fit the drift (fig. 115). A clench ring is a form of washer which is flat on the bottom with the top crowned and countersunk for the drift head. The impact of the sledge or hammer used in driving will generally upset the top of the rod sufficiently to form a head with a proper shoulder to fit the countersink. If not, it should be shaped by tapping with a ball-peen hammer. The point of the drift is generally riveted or peened over another clench ring, except where the drift is used to through-fasten a plank on edge such as a cabin trunk. In this case, the point is threaded and the drift is set up with a nut and washer. Where possible, drifts should be slanted slightly to increase holding power. e. Rivets. Copper rivets are the standard plank fastenings for lap strake construction. Elsewhere their use is restricted primarily to very light, thin-planked boats such as dinghies. This type of fastening is a copper wire nail riveted over a small copper washer called a burr or rove. The tool used to drive the rove on the r I I"\ @) CLENCH RING Figure 115. Three types of drifts. AGO 6244A nail is called a rove iron and is nothing more than a hollow punch. Every rivet must have a hole bored for it, and the size of the drill used must not be greater than the diameter of the nail. If the planking is a relatively softwood, the hole should be slightly smaller. After the hole is bored, drive the nail until the head is well-seated. Countersinking is not required. The rove is then placed on the nail point and driven on with the rove iron until it seats well against the wood. The next step is to cut the nail off with a pair of nippers, leaving just enough metal to form a good head over the rove, as shown in figure 116. If the nail is cut off too close to the rove, the head will be so thin after riveting that it will have very little holding power. If too much of the nail is left, the head will be upset or cocked, and the nail will bend somewhere within the wood. The amount of metal projecting above the rove after the point has been nipped off should be approximately one and one-half times the diam- TOP OR PIN MAUL---, (HOLDING IRON) Figure 116. Example of rivet installation and tools used. eter of the shank of the nail. The actual riveting is done with the rounded end of a small ball-peen hammer, while a heavy steel or iron weight, called a holding iron, is held against the head of the nail. The cut-off end of the nail is shaped to a slightly rounded head by a rapid succession of very light blows or taps. f. Glue. Two types of glue, resorcin resin glue and urea resin glue, are used extensively in hull construction. Resorcin resin glue is fully waterproof. Urea resin glue is water-resistant but should not be used where it would be subject to long periods of contact with water. Both types depend upon catalytic action for curing and have to be mixed prior to use. The manufacturer's instructions for mixing should be followed closely. A temperature of 71°F (21.1°C) is recommended as the ideal working temperature for glue. Lower temperatures cause slower curing, less penetration of glue into wood, and consequently a weaker joint. Higher temperatures cause the glue to cure faster, but do not impair the quality of the joint. Pressure is necessary to obtain a proper bond with glue. It can be applied by fastenings or by clamps. Softwoods, such as cedar or white pine, can be glued with light or moderate pressure. Woods of high density, particularly oak, require high pressure for a good bond. Observe the following procedures when using glue as a fastener: (1) Bring the two members into position and check for a perfectly fitted joint. (2) Clamp or wedge the parts together firmly in the desired position. (3) Strike one or more pencil lines across both pieces as check marks if there is any possibility of the two members sliding out of alignment. Line up these marks in the final assembly to insure that the two members are properly positioned. (4) Bore for any fastenings and have the fastenings and necessary tools ready while still clamped together. (5) Remove the clamps and place both members side by side or in a convenient position for spreading the glue. (6) Mix the glue, measuring carefully and stirring until it is free from lumps. Because it is difficult to know exactly how much glue will be needed for a given joint, it is better to mix a little more than is expected to be used. (7) Apply the glue evenly to both surfaces with a brush or knife. (8) Bring the parts together quickly and check for position. (9) Install fastenings and/or apply clamps as required. If sufficient glue has been spread and the proper pressure applied, a thin bead of glue will be squeezed out of the joint. (10) Allow joint to cure for a minimum of 8 to 10 hours before removing clamps. Note. Although glue will be dry in 10 hours at an average temperature of 70°F (21.1 o C), maximum strength is not attained for approximately 6 days. 130. Steam Bending Steam bending can be accomplished by one of two methods. The piece to be bent can be placed in a steam box or boiler, or it can be wrapped in burlap and boiling water applied to the burlap. If a steam box or boiler is not available, they can be improvised easily as shown in figure 117. When the piece is steamed, the bend can be attained either by installation into the desired position or by clamping to a form having the desired radius. Figure 118 shows a typical form. If the piece is clamped to a form, it should be allowed to dry thoroughly before removal, or it will tend to straighten when removed. 131. Laminated Bending For Knee or Stem a. Construct a form, similar to form used for steam bending (fig. 118), having desired bend radius. b. Cut laminates from white oak of a thickness that can be bent to form without steaming. Laminates should be cut slightly longer than required for the finished knee or stem. c. Prepare waterproof glue and spread on each laminate, laying them in wafer fashion. d. Clamp assembled laminates to the form and allow to cure. 148 AGO 5244A SIMPLE STEAM BOX WATER BOILER - MORE EFFICIENT RIG FOR STEAMING OR BOILING Figure 117. Typical improvised steam box and boiler. Note. Glue will usually dry in 10 hours, but approximately 6 days is required before full strength is attained. e. Remove from form and cut to size. Figure 119 shows a typical laminated knee and stem. 132. Splicing and Joinery-General The scarf is a joint peculiar to vessel construction and is commonly used in joining structural members such as the keel, stem, or AGO 5244A framing. It is also used in planking and various other structures 'Of the vessel. The term scarf is a form of splicing, and regardless of where it is used, there is one principal requirement to be met. The lne of the scarf joint must not cross the grain of the wood at an angle greater than 5 degrees nor attain more than a l-inch rise in every 10 inches of run. Anything more than this will produce a weak joint. STAGGERED FASTENINGS Figure 118. Form for steam bending. Figure 119. Laminated knee and stem. The joining of the scarf should be given careful consideration, whether it be glued, bolted, or fastened with drifts or screws. The strength of the scarfed joint is within the fastening. When a scarf joint is made, it should be held together firmly, with no light visible anywhere along the joint. One way to determine if the joint is fitted correctly is to chalk orie piece with blue chalk, join the scarf sections, and clamp them securely together. When they are separated, if the joint is good, there should be an even transfer of chalk from one piece to the other. If the joint is not properly fitted, COMMON SCARF HOOKED SCARF EXCESS CHISELED AWAY TO THIS LINE Figure 120. Common and hooked scarfs. the blue chalk will spot the high areas, and these can be cut down with a chisel. When making a joint, do not leave the end grain of a plank or timber exposed. Many woods will split, or craze and crack, when moisture enters the end grain. Also, end grain will tend to weep or shed resin, marking the finish paint or, in the case of a varnished surface, showing up as a very dark area. a. Common and Hooked Scarfs. The common scarf is used primarily in keel members, but is occasionally used in bilge stringers, clamps, and shelves. The hooked scarf is used in keel timbers but rarely elsewhere. This type is an improvement over the common scarf because it has a jog in the middle which prevents the two members from working lengthwise. The common and hooked scarfs both terminate in a lip. Common and hooked scarfs are shown in figure 120. There is generally sufficient depth in a timber to cut a shallow lip without weakening the joint. The simple plank scarf is a glued joint, used in spar making and in joining planks in lapstrake hulls without butt blocks. Strength in a scarf is obtained by the fastening: glue, bolts, or drifts. The plank scarf 150 AGO 5244A strength is obtained by a glue line, and the longer the glue line the greater the strength, so a lip is not practical. There is not sufficient thickness to cut the lip without weakening the plank drastically. ( 1) A common or hooked scarf for a timber is laid out as follows: (a) Make a pattern to exact dimensions on heavy paper or cardboard. (b) Tack cutout pattern on each member in turn, with outline drawn in pencil. (c) Square ends or lips across top and bottom of timbers and trace outline on opposite side. (d) Cut scarf with a handsaw because most timbers are 4 inches or more in width. (e) Cut from one side for approximately 2 inches, then turn timber over and cut from other side. Cuting alternately from each side lessens danger of running off line. (f) Fit both timbers together when they have been cut, and see that they are perfectly straight lengthwise. No daylight should be visible through a perfectly fitted joint. (2) The method of cutting hooked scarfs requires some explanation. In figure 120 showing the hooked scarf, note that the outer half, or end piece, will be removed by two saw cuts. The shaded half must be taken off with a chisel as follows: (a) Use chisel no less than 1V2 inches wide. (b) Use wooden mallet, not a hammer. (c) Do not take a big bite in wood; thin chips mean more control and less danger of splitting off more than required. (d) Cut both ways toward shoulders, and when near finish line, discard mallet and finish by hand. (e) Note that a small block plane can be used where there is room, but chisels must be relied upon to make shoulders true and square. (3) The simple plank scarf requires more skill to make than a timber scarf, as AGO 5244A Figure 121. Typical plank scarf. 5 DEG MAXIMUM DIRECTION OF CUT Figure 122. Construction and use of jig for cutting a plank scarf. a mechanically perfect joint must be made if it is to have any value at all. The plank scarf is made as follows: (a) Square both surfaces exactly with edge and face of plank. (b) Slice the two planks at same angle. (c) Insure that planks are in perfect line when glued. The finished assembly will have a twist at the scarf if one surface is not square across the face, and the two planks will not lie in the same plane. Figure 121 shows a typical plank scarf. (d) Stagger boring holes for fastenings in scarfs, rather than right on centerline, so that they do not all go through the same line of grain. (4) The easiest way to make a perfect scarf joint is to use a jig such as that illustrated in figure 122. A jig consists of a 2-inch plank, slightly wider than stock to be scarfed, and two side pieces which serve as guides or runners for a hand plane. A jig is made up as follows: (a) Select a 2-inch by 6-inch plank, 6 to 8 feet long, that is straight, square, clean, and unwarped. (b) Scribe off one end with a steel square and cut off true and square. (c) Use a fine-toothed saw to insure that cut will be clean and sharp. (d) Get two identical pieces of oak, 3,4 inch by 3 inches, 30 inches long, with edges planed square and straight. (e) Place them side by side, and square a pencil line across edges 10 inches from one end. (f) Nail these pieces on either side of 2-inch by 6-inch plank with pencil lines coinciding with squared end and at required angle of 5 degrees or at a l-inch rise in 10 inches of run. (g) Sight across pieces from side to side to determine that they are alined accurately. (h) Mount jig on two sawhorses so it cannot shift by toe-nailing edges of the 2-inch by 6-inch piece. (5) Figure 122 shows the type of construction and use of a jig. The following is one accepted method of using a jig: (a) Cut ends of the two planks to be scarfed to approximate angle or taper with a rip saw. (b) Lay one on jig with scarf end advanced slightly. (c) Line it up straight and set up a C-clamp approximately 3 feet in back of scarf. (d) Support end not in jig by another sawhorse. (e) Plane scarf carefully to a perfect surface with feathered edge. (f) Use a long plane for planing, either. a Fore No. 6 or a Jointer No. 7. (g) Set plane iron for a very fine cut. Note. The plane is held diagonally, with the toe on one side piece and the heel on the other, but direction of cut is straight down the scarf. (h) Reserve last few cuts for feather end which is an angle of 5 degrees. (i) Check to insure that both surfaces are square. To ascertain this, use a tri-square and sight into a source of light. (j) Move tri-square to various positions on surfaces to check for any high spots or hollows. (6) To glue a plank scarf, the procedure is as follows: (a) Use a long, straight, smooth surface such a 2-inch plank, 10 to 12 feet long, nailed to two sawhorses. (b) Lay the two planks on this working face with scarf in center. (c) Support ends with more sawhorses or boxes, and shim them if necessary to have the two planks in a straight line. (d) Place bottom plank on 2-inch plank so that it is even with working edge. Slip a piece of waxed paper under feather end, and secure with a C-clamp near scarf. (e) Lay top plank in position flush with edge of 2-inch plank. (/) Hold a steel square on bottom plank while sliding top plank along to correct position. (g) Make a pencil mark across edges of scarf while holding top plank in position. (h) Line up these marks when ready to glue. Coat both surfaces of scarf evenly with glue. ( i) Use at least four C-clamps, two for the scarf itself and at least one on either side, to hold planks in position. (j) Use a piece of oak approximately % inch by 4 inches to go under clamps and over scarf to distribute pressure evenly. (k) Always use waxed paper when gluing to prevent sticking. (l) Check for proper alinement by sighting along edges of assembly. (m) Allow to cure for 10 hours at a temperature of 70°F. (21.1 °C.) when properly glued and clamped. AGO 5244A b. Plywood Scarf. Plywood is manufactured in various lengths, and stock is usually available in 4-and 8-foot sheets. If there is need for additional length on a particular job and the stock does not meet the demand, a piece can be scarfed on. Assuming that there is need to lengthen a piece of 3-sheet plywood, the following should serve as a guide: (1) Support sheet on a solid rest, easy to reach and work. (2) Check end for squareness, then measback 8 inches and mark. A steel straightedge, long enough to reach across sheet and having a true edge, will be needed. (3) Fasten straightedge at 8-inch marks with small C-clamps. ( 4) Run blade of a knife or sharp tool across sheet a number of times using straightedge as a guide, until there is a cut through first veneer or ply. Note. Be careful not to cut too deeply, or the second veneer will be damaged. (5) Cut away first ply with a sharp chisel without removing straightedge. (6) Work chisel with grain toward straightedge. (7) Take remaining wood off with a sharp block plane, set very fine, when layer of glue is barely visible. (8) Clean up line sharply next to straightedge with chisel. (9) Move straightedge 4 inches from end clamp in position. (10) Remove second ply to glue line as before, and one half of scarf is finished. Note. The second ply grain runs crosswise of the sheet and can be cut easily. Care must be taken to avoid scoring or cutting into the third ply. ( 11) Cut an identical scarf on end of second sheet, measuring accurately to insure it is identical and ready to glue. (12) Coat scarf surfaces of both pieces with resorcin resin glue. ( 13) Join pieces, under pressure, and allow to cure. Note. A minimum pressure of 600 pounds is required to assure proper bond. AGO 5244A COMMON LAP JOINT COMMON LAP JOINT WITH CORNER POST RABBETED POST BUlLT-UP CORNER POST Figure 123. Common joints. c. Common Lap Joint. This is the most unsuitable type of joint for vessel work because, as seen in figure 123, the fastenings are driven into end grain and have little holding power. The only suitable fastenings for end grain are wood dowels set in waterproof glue, and these are limited to certain strength requirements. There are other faults with this type of joint also, such as exposed end grain and sharp corners that are subject to splintering under normal wear and tear. To remedy one of the deficiencies of the type joint, a corner post can be added, as shown in figure 123. This will make a much stronger joint, as there is something solid to be fastened. The end grain is still exposed, however, and the sharp corner remains. d. Rabbeted Post. This type of joint (fig. 123) solves some problems of the common lap joint. The end grain is completely hidden, and the joint has ample strength in the fastenings. The corner post is first taken out, rabbeted, and fitted in the square; the outer corner is then carefully rounded with a block plane to fair in smoothly with the side planks. The size of the corner post should be worked out on paper first to be sure that enough stock has been provided to take the proper size screws. e. Built-up Corner Post. The built-up corner post (fig. 123) shows a useful variation. There are occasions where it is desirable to have a much greater radius to the corner. Here the corner post is in two pieces, the outer or filler piece being fitted last and screwed and plugged to the inner piece. This construction avoids the necessity of using very heavy stock, which would be required if it were in one piece. This should be carefully laid out on paper to insure a well-fitted job. The joint should be glued on all mating surfaces. 133. Scribing, Spiling, and Template Making a. Template Materials. Templates help to standardize an operation which must be performed a number of times. In other cases, they make possible the transfer of shapes or forms from one object to another without actually having to handle the objects themselves. For example, a template can be taken from the foot of a heavy piece of machinery and used as a pattern to build the correct shape on the foundation. The machine can then be moved to the foundation and installed in one operation. There are four kinds of templates used in vessel construction and repair: wire, wood, paper, and metal. (1) A wire template (fig. 124) is a piece of wire sturdy enough to retain shapes to which it is bent to conform with a particular job, such as pipes, hatch canopies, and footrails. (2) Wood tempaltes (fig. 125) are made from light weight lumber, such as white pine or mahogany. They are usually very sturdy, not likely to lose shape, and can be used repeatedly. (3) Paper templates (fig. 126) have many uses. Their durability is limited when subjected to constant use, but for re- PIPE BENT TO CONFORM TO SHAPE OF WIRE TEMPLATE Figure 124. Wire template. Figure 125. Wood template. Figure 126. Paper template. pair to a damaged vessel, the paper template is expedient. Paper can be marked and cut with almost any available sharp tool. In making flange templates, a ball-peen hammer can be used; hold or clamp the paper over the flange and lightly tap the sharp edges, cutting the circumference. The bolt holes can be tapped out with the ball end, using the same method. It is important, however, that light blows always be used, so as not to burr or mar the flange. (4) Metal templates (fig. 127) are very durable and can be marked out from AGO 5244A Figure 127. Metal·template. a paper template. The metal template is used for an assortment of standard flange templates. They can also be used to make many fibrous gaskets for stock on a vessel. b. Spiling or Scribing a Curve. Spiling and scribing are essentially the same thing: the laying out of the line to which a board must be cut to fit a specific curve. The difference between the two can be noted when speaking of planking a hull; a plank is scribed at the end to fit the curve of the rabbet in the stem, while it is spiled along the edge to fit against the next plank above or below. The curve that exists is transferred to the board to be cut with the aid of a pair of dividers or pencil compasses. Figure 128 shows two elements: the curved line at the left which might represent the rabbet line of the stem, the crown of a deck, or the inside of the hull planking; and the square end of a board at the right, which might be a bulkhead, hatch coaming, or shelf. The series of dotted lines at regular intervals are merely reference points, but note carefully that they are parallel to the top and bottom edges of the board. ( 1) With end of board placed close to curved line, open compass to span distance with a little extra to spare, and then tighten to hold the span. (2) Place one leg of compass on line of curve, and tick board at top edge with other leg. Drop down a short distance and repeat same procedure. AGO 5244A I I I I __*I ______________ _ I I I I --------:It----------- \ \ \ \ \ \ SCRIBING A CURVE H LAYING OUT BULKHEAD Figure 128. Scribing a bulkhead. Note. Keep the compass parallel to the top edge of the board at all times during the marking; remember that the greater the number of tick marks, the fairer the line, and the nearer the duplication. c. Typical Spilling Problem Laying out Bulkhead with Template. Figure 128 shows a half section of an open craft. Assume that it has a round bottom. To fit a plywood bulkhead athwartships near the bow, it is obvious that the plywood sheet cannot be held in the proper position to scribe the hull contour on it, so a template must be taken. Using heavy cardboard or wallboard, proceed as follows. ( 1) Cut a straight sided piece and place it next to frame, with each end resting against planking and lower end extending below floor timber. (2) Scribe and mark curved line of the side with a pencil compass. (3) Mark point of intersection of top of floor timber and sheer, or top edge of hull, at side. (4) Cut template carefully on a handsaw to outside of pencil line. ( 5) Lay template on sheet to be fitted and place in correct position as to centerline, heights, and half-breadths. Mark shape onto stock; turn template over and complete other side. Note. When cutting this material out, allow l;ls inch outside the line. This will leave ample extra stock for final fitting. Make as many trial fits as necessary before cutting off too much. Figure 128 shows the template on the material in proper position for marking. d. Sawing to Template. After the template has been made, it should be checked for fit. Check and doublecheck all measurements to avoid any error. Place template on stock to be .cut. Before cutting any material to a template size, insure that the material is of the correct specifications and that there is sufficient material to allow at least a ~!J. 6-inch nverlap all the way around the template. Never cut any material to the exact template size, but always larger. This will provide added security in case of any error or irregularity in the template. e. Trimming to Fit. The trial-and-trim method is time consuming, but the result is a perfect fit. Place material in location for which it is cut, and mark low and high spots. Then remove and trim out accordingly. This can require several repetitions of the fitting and removing. f. Preparing Butt Joint. The preparation of a butt joint requires the cut on the material to be clean and square. No saw makes a sharp edge cut. The teeth actually tear the wood fibers apart. This is most noticeable on the underside of a cut. To eliminate the rough, ragged edges of a butt joint, use a steel straightedge instead of using a pencil line, and score a line with a sharp knife. Make a clean scribe, no deeper than lfa 2 inch. When sawing to this mark, saw very carefully just outside scribe mark or where saw teeth just miss the line. This will make a clean, sharp edge for joining. In the event that a butt joint has been cut, one section has already been fastened off, and the outer cut surface does not make a clean fit, clamp the other board in position as close as possible, and then run a crosscut saw through the joint. Remove clamp and bring board up against joint; it should be well fitted. 134. Planking Repairs-General The major types of plankings are carve! or flush planking, clinker or lapstrake planking, batten seam planking, double planking, and plywood planking. This paragraph does not cover the full details on each type of hull and the many different types of planking repairs that can be encounten~d. The intent is to familiarize the repairman with the type of construction and act as a general guide to aid in the repair of the planking. a. Carvel or Flush Planking. Carvel or flush planking is by far the most common of the planking methods. As shown in A, figure 129, the plank edges are butted against each other and fastened to the frames. Where the frame curvature is extreme, the planks are proportionately narrower and hollowed out inside to fit the round of the frames. In all carve! planking, a slight V-groove, opened outward, is left at the seams for calking. Fastenings are through the frames as shown in figure 129. This is the easiest way to plank a hull and also has the advantage that broken or rotted planks are easily replaced without removing adjacent planks or frames. Except on small, light hulls, the minimum thickness of planks should be 1 YJ 6 inch, as boards of lesser thickness will tend to twist and crack. One disadvantage is that recalking is necessary at times during the vessel's life and is dependent upon the quality of the original calking job. A very smooth finish can be obtained by using this method of planking. Narrow strakes are preferred, as there is less swelling and opening of the seams. All planks should be hollowed or fitted to the AGO 5244A A. CARVEL OR FLUSH PLANKING C. BATTEN SEAM PLANKING THROUGH FASTENING CANVAS DOUBLE PLANKING 0 1 • B. CLINKER PLANKING Figure 129. Common planking methods. curve of the frames and well fastened. Seams b. Clinker or Lapstrake Planking. The should be perfectly tight inside and open outclinker or lapstrake method of planking has side so the calking can be driven in tightly the advantage of being watertight without the without driving it through. use of calking, of not having seams shrink AGO 5244A 157 open in heat, and of being lightweight. Its disadvantages are that broken and rotted planks are difficult to replace and planks must be carefully beveled into each other at the transom. Lapstrake planking is employed mainly in small dinghies and skiffs. It is also desirable where the planking would be too light for calking. A good clinker job requires very skillful work and the best of material. All bevels where the planks lap must fit perfectly, and joints and frames must be thoroughly fastened. Although a plank can be replaced, repairs are not as easily made as with the calked seam hull. An example of clinker planking is shown in B, figure 129. c. Batten Seam Planking. Batten seam planking is a type of building developed for use in V bottom designs. The plank edges are fastened to continuous battens and frames to insure watertightness. For its weight, seam batten planking is the strongest of the many methods. Frames can be spaced further apart and the battens take the part of longitudinals. Batten seam planking is extensively used in small vessels of the hard-chine variety. The advantage of this planking is that it permits the use of light planking in connection with widely spaced frames. Because the seams can be made tight through the use of battens, there is no need for a calking seam. Planks are usually butted together and need no opening. While the deep, sawed frames of this type hull are easily notched out for the battens, this construction is not practical ~ith smaller and more closely spaced frames. Round-bilge wood vessels have been constructed with batten seams. The notches for battens seriously weaken the lighter, bent frames; therefore, filling pieces are employed between the battens. An example of batten seam planking is shown in C, figure 129. d. Double Planking. The double planked wood hull is made up of inner and outer planking. The inner planking is full length without butts. It is laid diagonally forward at approximately 45 degrees. The planking is screwed to the keel, chine rabbets, and the sheer clamps, and is nailed to the frames. The outer planking can run longitudinally. The butts are staggered and made on butt blocks between frames. The planking is fitted as tightly as possible with no calking in the seams except at the garboard strake seam. This seam is calked lightly with cotton and filled with surfacing putty. The outer planking is fastened with three screws in each plank at each frame. The screws are set below the surface of the planks only far enough for planing and sanding the hull, and are covered with a hard surfacing putty. The inner and outer planking is fastened together with screws from the inside. These screws are spaced 2 inches apart, and there are two rows in each bay between two frames. The arrangement of double planking ·can vary. In some hulls, the two layers run parallel to each other; in others, double diagonal, and still others, 45 degrees to the two layers. Planking at 90 degrees to each other is ideal for the underwater planking of a V or flat bottom hull. In all double planking, a layer of canvas, soaked in marine glue, is applied between the inner and outer planks. Fastenings are at the frames and also between the frames to bind the entire skin together. Double planking is exceptionally strong and watertight. Because of its rigidity, double planking can be thinner than carvel planking. Double planking is best with a light, closely spaced frame so that the thin outer skin is closely fastened. Where the frames are widely spaced, there must be many fastenings through the two skins between frames. Double planking is shown in D, figure 129. To repair small gouges in the planking, a section can be cut away and fitted. If the damage does not go through the outer plank, cut only as deeply as necessary. Serious cuts and cracks are repaired by replacing a section of plank, but generally it is advisable to replace the entire plank. When sections are cut from planks, cut so that the joints are staggered. Use larger fastenings or plug the old screw holes with wooden pegs or plugs, and duplicate the fastenings of the old plank as closely as possible. e. Plywood Planking. The modern waterproof marine plywood planking is in reality a form of prefabricated double or multiple planking. Plywood is being used for the planking of small and some large vessels. The advantage is that plywood is strong, light, and quickly applied. For small vessels, there are fewer seams to cause leaks, and those that are necessary are easily made perfectly tight. Fastenings at the AGO 6244A chines and edges of the plywood are usually wood screws in combination with waterproof glue. 135. Replacing Planking on Double Planked Hull a. Removal of Outer Planking. Caution: Be careful, when removing outer planks from hull, to damage as little as possible of the cotton duck between the two layers of planking. ( 1) Determine planks to be removed. Locate and remove screws fastening planks to frames. (2) Remove lining screws in inner planking. (3) Locate center of bay between frames for new butt joint by measuring from lines of screws which fasten planks to frames. (4) Square plank with seams and mark (fig. 130). ( 5) Nail a small wood strip on line to aid in making joint straight. ( 6) Chisel out a small section of plank where marked (fig. 131). (7) Chisel out center of plank first when a single outer plank is removed, so edges of remaining planks will not be damaged. (8) Remove remaining portion of plank carefully. (9) Cut cotton duck evenly around damaged area with at least a 2-inch margin inside remaining outer planking. (10) Remove cotton duck. (11) Mark remaining outer planking to locate opening on new planking for through-hull fittings if necessary. b. Removal of Inner Planking. ( 1) Locate and mark diagonal planks to be removed. Ends of planks to be replaced should fall on center of frames or bulkhead. (2) Chisel out planks carefully so not to damage frames or bulkhead (fig. 132). ( 3) Remove planks. ( 4) Repair frames if necessary. AGO 5244A Figure 130. Marking location of butt joint. Figure 131. Chiseling out at new butt joint. Figure 132. Chiseling out inner planks. c. Installation of Inner Planking. (1) Cut and fit inner planks (fig. 133). Use o/s inch thick spruce for topside inner planking and 1;2 inch thick spruce for bottom inner planking. Plant all edges of planks before final installation. ' Figure 133. Fitting new inner planks. (2) Coat edge of bulkhead with white lead where new inner planks cross or edges of planks fall on a bulkhead. (3) Place new inner planks in position and fasten to frame and bulkhead with sixpenny, common, galvanized nails for topside planks or copper nails on bottom. ( 4) Cut a new section of 6-ounce cotton duck large enough to lap 2 inches over edges of old fabric. (5) Apply a coat of dolphinite, covering inner planking and 2-inch strip on edges of old fabric. (6) Tack or staple one edge of new fabric. (7) Stretch and press fabric into dolphinite (fig. 134, step 1). (8) Tack all edges of fabric (fig. 134, step 2). (9) Trim off excess fabric at inner edge of remaining planks. d. Installation of Outer Planking. (1) Cut and fit new outer planks. Topside outer planks are 5fs inch thick mahogany and bottom outer planks are %inch thick mahogany. Note. Steam bending will be necessary for some outer planks. (2) Locate line for fastening screws into frames by placing a straightedge on centers of line of screws above and below new outer planks. (3) Drill three holes through each plank into frames for fastening screws. Figure 134. Applying new fabric. Counterbore holes only enough that screwheads will be cleared when planing and sanding hull. Use electric drill with tapered bit lft6 inch smaller than shank of screw. ( 4) Remove new outer planks. (5) Apply dolphinite on all exposed fabric. (6) Apply dolphinite on inner surface of new planks. (7) Place new outer planks, fastening first I planks temporarily with nails until all planks are set in proper position. (8) Place screws in holes and tighten. (9) Drill holes for butt joint bolts through planks and butt lock. AGO 5244A Note. For new butt joints, drill from outside, and for old butt joints, drill from inside through old bolt holes in old butt block. (10) Counterbore holes so bolt heads will be flush after sanding of hull has been completed. ( 11) Tap bolts into place using a hammer. (12) Install six washers and six nuts on bolts for new butt joints and three washers and three nuts on bolts for old butt joints. (13) Drill holes from inside for lining screws which fasten inner and outer planking together. Use electric drill with 1,4-inch tapered bit. Note. The depth of drilled hole should be % to :1,4 inch less than length of screw to be used. (14) Install l-inch, No. 10 flathead lining screws. (15) Sand down, when new planks are installed, to a very smooth finish matching surrounding planks. Use disk sanding machine (fig. 135, step 1). Finish sanding with sandpaper (fig. 135, step 2). (16) Apply one coat of primer paint. Use hull or deck paint thinned down with 1% quarts of linseed oil to 1 gallon of paint. (17) Fill screw and bolt holes and any open seams with putty or seam compound. ( 18) Sand repaired area after paint and compound dry. (19) Apply specified paint. 136. Repairing Deck Planking and Covering a. Determining C01·rect Amount of Damaged Area to Remove. When a damaged area is between two deck beams, the section to be removed should be cut so the edges are centered over the beams. Place a transverse butt block under the entire new section and 41;2 inches beyond the seam. b. Measuring for New Planking Section. Determine the location of the deck beams beneath the damaged area by measuring through the hole in the deck to the nearest deck beam. Measure the thickness of the beam and add one half the width to the over-all length. Check all AGO 5244A STEP 1 STEP 2 ) ~ ) v.l ) )_./ /) Figure 195. Finishing planks. I I'' I I 1/'QII II I I ~ ;.;' I I I \' II ,,II I Figu1·e 136. Marking damaged area to be removed. measurements for accuracy, then transfer these to the new material. Cut the new material, lightly nail it in the correct position over the damaged area, and mark carefully around it onto the deck (fig. 136). c. Cutting New Butt Ends. After all the lines are transferred to the section to be removed, place the new material aside, and drill starting holes in the corners of the damaged deck for the keyhole saw. Use a brace and a l-inch bit. Drill the holes so the edge will cut near the line of cut. Use a keyhole saw to cut all but the area over the beams, then use a cross-cut saw, held at a low angle to avoid cutting the beams. Use a rasp, chisel, or plane to true up the edges of the opening in preparation for the new material. d. Fitting Plank to Hull Curvature Using Spiling Batten and Dividers. When a plank is to be replaced, a spiling batten is necessary to obtain the correct shape for cutting the new plank. A spiling board is of softwood, % inch thick, and as long as the board to be fitted. (1) Fasten spiling board to frames temporarily, after damaged section has been removed. Note. Let the batten take its own shape and position, making no attempt to spring it sideways in order to get it parallel with the edge of the remaining deck. (2) Place one leg of dividers on surface of batten and extend other leg to edge of shaped edge of decking. (3) Make a small mark on batten with point of dividers, and mark an X with pencil at this point. (4) Move dividers entire length of decking edge, making marks at short intervals. Record location of these marks with penciled X, as before. ( 5) Mark location of frames on batten. Figure 137 shows a spiling batten in position, with location marks being made with dividers. (6) Remove batten and place in position on new material to be fitted after location marks have been placed throughout length of batten. Secure both batten and new material so there will be no movement. FRAME SECURED BY LOCATION TACKING AT EXISTING MARKS DECK THESE POINTS FRAMES (7) Mark frame location on new material, then transfer all location marks from batten to new piece. Note. Always keep dividers perpendicular to line of location marks. ( 8) Remove spiling batten and tack some small finish nails along location marks on new material after all location marks have been transferred. A small flexible piece of batten can be placed against there finish nails to serve as a guide for drawing a line joining the marks. (9) Remove batten and cut new material to line drawn. Note. Make cut just a fraction outside line to allow for any slight irregularities. This will give enough material to make a near perfect fit. e. Instalring New Plank. Before the plank can be installed, butt blocks must be fitted and 13ecured in place. A typical procedure for installing butt blocks is as follows: (1) Cut butt blocks from l-inch fir plywood. Butt blocks must extend 41/2 inches on each side of seams and the full width between deck beams. (2) Fit butt blocks into position, as shown in figure 138, and fasten temporarily with clamps, wooden props, or nails. ( 3) Drill holes, 3 inches apart, for screws fastening planking to longitudinal butt blocks and deck beams. Use elec- Figure 137. Fitting a plank to hull curvature. Figure 138. Fitting butt blocks. AGO 5244A tric drill and 1,4-inch tapered bit with 1;2-inch counterbore. (4) Drill holes, staggered 3 inches apart, for bolts fastening planking and transverse butt blocks. Use electric drill and %6 -inch straight bit with %inch counterbore. ( 5) Remove butt blocks. (6) Coat matching surfaces of butt blocks and old deck with glue. (7) Fasten longitudinal butt blocks with 2-inch, No. 14 flathead screws. Use electric drill with screwdriver bit. (8) Fasten transverse butt blocks with %6 -inch flathead bolts, washers, and nuts. Use brace with screwdriver bit and %-inch open-end wrench. (9) Mark position of deck beams and butt blocks on old deck planking. (10) Place new deck plank and mark posi tion of deck beams and longitudinal butt blocks. (11) Drill holes for screws fastening planking to deck beams and butt blocks. Use electric drill with 1,4-inch tapered bit and .%-inch counterbore. Figure 139 shows tapered, straight bit, and counterbore. (12) Extend drill 1,4 inch further through counterbore attachment for holes into beams. Stagger all fastenings 3 inches apart. ( 13) Mark area, from below deck, of new plank which is covered by butt blocks and beams. (14) Coat matching surface of new plank and butt blocks with glue. (15) Install bolts through plank and transverse butt blocks. (16) Tap bolts into position with hammer. (17) Install washers and nuts. Use brace with screwdriver bit and %-inch, open-end wrench. ( 18) Install screws fastening plank to deck beams, and longitudinal butt blocks from above and below deck. Use electric drill with screwdriver bit, or ratchet screwdriver. (19) Sand new deck plank. Any small lumps left under cotton duct covering will cause excessive wear at these points. (20) Apply primer coat of deck paint. (21) Cover bolts and screws with putty. ( 22) Sand deck planking, carefully removing all rough spots. · (23) Apply shellac on starting edge of new piece of No. 12 cotton duck to keep edge from raveling. (24) Trim shellacked edge of material evenly. (25) Apply coat of white lead on exposed deck planking, extending it 3 inches over edges of old deck covering (fig. 64). Figure 139. Tapered, straight bit, and countet·bore. Figure 140. Tacking deck covering. AGO 5244A (26) Tack shellacked edge of fabric. Use %-inch copper tacks spaced 1,4 inch apart (fig. 140). (27) Stretch fabric lengthwise while pressing into white lead and tacking other three edges. (28) Apply shellac in a strip across fabric where it will be cut, making a firm edge. Trim off excess material. Caution: Do not cut original deck covering when trimming new fabric. (29) Soak new fabric to shrink it. Use water and sponge. (30) Paint new deck covering while still wet. 137. Garboard Strake Repairs The first plank to be fitted to the frames is the one next to the keel. This plank is called the garboard strake. In order to have the garboard strake fit properly, it must be shaped. A. practical method of shaping the garboard strake is by spilling, as follows: a. Obtain a board about 1fs inch thick and bend it over the frames along the keel. It can be necessary to trim along its length to allow the board to come somewhere near the keel. It need not be a perfect fit and can in some places come not closer than 2 inches to the side of the keel. This lfs-inch plank is called the spiling plank. b. Tack spiling plank lightly in place, permitting it to spring naturally over the frames with forcing in any manner. Tack to frame sufficiently to hold in place temporarily. If one piece of sufficient length cannot be obtained, two or more pieces can be securely fastened together. c. Erect perpendicular lines on spiling plank at 3-or 4-inch intervals. d. Take the spilings now with the aid of a compass or dividers. Set points of compass so that they are a little wider than the greatest space between inside edge of rabbet line of keel and edge of spiling plank. Note. The distance between the eompass points should not be shifted during the spiling operation. e. Start either forward or aft, and place one point of compass where perpendicular line on spiling plank intersects inside edge of keel rabbet; scribe an arc with other point which will intersect perpendicular line on spiling board. This should be done the full length of garboard strake. f. Remove spiling board with this operation completed, and place it upon material from which garboard strake is to be cut. g. Allow sufficient space along working edge of plank for maximum span of compass points. h. Reverse procedure and transfer spilings to plank, thus arriving at actual line for garboard strake. i. Join arcs on garboard strake with a fair pencil line drawn with the aid of a batten. Cut excess plank away. Note. If the above procedure is followed carefully and the work done properly, the garboard strake will fit perfectly into place. Before fastening into place, the outer edge of the strake should be planed so there will be a slight V for calking. 138. Decayed Wood a. Replacement of Decayed Wood. The most important consideration in removal and replacement of decayed wood is_ to find the cause for decay and correct it. In removing sections of wood, adding sister frames, or splicing, more end joints and faying edges are created, providing additional places for moisture to collect. If the original cause of decay has not been removed, the chances for additional decay will have been increased by the repair. Wood members which are extensively decayed should be removed entirely. Where decay is localized, removal in the decayed member should be to a distance approximately 2 feet along the grain and 2 inches across the grain beyond the point where decay is evident. The heartwood of decay resistant species, such as white oak, cypress, tropical American mahogany, teak, Douglas fir, Longleaf yellow pine, Port Orford cedar, and Alaska yellow cedar, are preferred for repair replacement. The selection should take into account the physical properties required for the member to be replaced. Alaska or Port Orford cedar can be substituted for any planking species presently noted on the applicable plans, except mahogany. Sapwood in any species should be excluded. When it is impossible to exclude all sapwood in the finished replacement member, the sapwood face or edge should not be AGO 6244A placed at a faying surface. Red oak has inferior decay resistance and is not suitable as replacement material unless it is pressure-preservative treated. Distinguishing red oak from white oak and sapwood from heartwood is sometimes difficult. A kit of chemicals for positive identification of oak and sapwood is available from supply upon request. In regard to plywood, overlaid panels are preferable for exterior horizontal components where checking is normally a problem with conventional Douglas fir plywood. The moisture content of all replacement lumber will be 13 + 3 percent at the time of installation. The moisture content of all replacement plywood will be 10 + 5 percent at the time of installation. b. Decay Prevention and Repair Practice. There are three fundamentals to be observed in decay prevention: (1) The use of dry lumber and the correction of any feature apt to increase the moisture content of the lumber after installation, such as insufficient ventilation or fresh water leaks. There is no such thing as actual dry rot. Decay fungi require moisture and air. Lumber below 20 percent in moisture content will not decay; submerged lumber will not decay. The misleading term dry rot was derived from the dry and powdery appearance of wood that had decayed while moist and subsequently dried out. (2) The use of all heartwood lumber of a decay-resistant species. Such species are necessary also because of their dimensional stability, their slow rate of water absorption when submerged, and their usually lighter weight. Sapwood of any species has very low resistance to decay. (3) The use of preservative chemicals and fortified bedding compounds. Such materials and salt water prevent decay by making the wood poisonous to fungi. c. Corrective Measures. During repair, the following corrective measures must be taken into account to prevent the occurrence or reoccurence of decay: the addition of well-placed AGO 5244A Figure 11,.1. Removing metal guard. port and starboard ventilators or the extension of the existing mechanical ventilation system to unventilated compartments, and the alteration of tight cargo flats, ceiling (inner sheathing), or filler blocks to permit air circulation to the bilges and between bays at the frame head level. Cargo flats shold terminate at the inboard faces of the frames, and a strake of ceiling should be employed to prevent trash accumulating in the bilge. 139. Repair of Chine Guard n. Genend. The chine guard and rub strake are designed to prevent damage to more vital t>arts of the vessel when coming in contact with -a dock or floating objects. Therefore, they must be replaced fairly often. If damage is extenl;;ive, remove the damaged peices in entire sections as they were built on the vessel. If damage is confined, it is permissable to replace the damaged portion with a graving piece. When a new chine guard is shaped and installed, it does not overlap or come flush with the bottom of the chine. The bottom of the chine extends at least % inch below the bottom of the guard so the force of water will not rip the guard off. b. Replncement of Ch,ine Guard Section. Replacement of a damaged section of chine guard should be handled in the following order: (1) Remove screws fastening half-round metal guard on chine guard. (2) Remove metal guard as shown in figure 141. (3) Remove metal butt piece beneath joint of metal guard. This can be seen in place in figure 141. (4) Locate and remove screws in upper and lower edges of chine guard. ( 5) Pry chine guard loose using a wreckbar. (6) Saw off any nails that are protruding. (7) Plug up all old screw holes. (8) Cut and shape new section for chine guard from oak. (9) Steam bend forward sections of chine guard by placing new section in a steam box for approximately 30 minutes or until pliable. (10) Remove section from steam box and fit into position on vessel while it is still hot. (11) Nail section into position temporarily and allow to cool and dry. (12) Drill screw holes 6 inches apart. Stagger holes in upper and lower edges of chine guard. Counterbore screw holes so screw heads will be set in flush. (13) Remove new bent section from vessel. (14) Paint inner surface of new section, matching surface on vessel, and scarf surfaces, using topside paint. (15) Install new section and secure with screws. (16) Chisel out recess for metal butt piece of metal guard joints. (17) Paint face and outer surfaces of chine guard; install but piece. ( 18) Install metal guard. c. Repairing Chine Guard with a Gmving Piece. In the event only a small portion of the chine guard is damaged, accomplish procedures b(1) through (3) above, then proceed as fol lows: (1) Mark damaged section and carefully cut away with hammer and chisel. (2) Measure section removed for length, width, thickness, and bevel. (3) Cut a piece of oak to these measurements. ( 4) Make a final fit of graving piece. Apply glue on all contact surfaces and fit into place. ( 5) Install proper screws, counterbored so screw heads will be bush with surface when graving piece is finished. (6) Plane and sand graving piece flush with surrounding surfaces. (7) Paint graving piece and replace metal guard. A typical installed graving piece is shown in figure 142. 140. Repair of Coaming When damage to a coaming is confined to a limited area, as shown in figure 143, it can be repaired without replacing entire coaming as follows: a. Cut away damaged area in coaming and cap. Slope cut at each end to allow for fastening of graving piece. b. Select wood repair stock to match existi11g coaming. Clamp repair stock onto coaming and mark outline of repair area. INSTALLING INGRAVING PIECE . IN CHINE GUARD Figure 142. Graving piece installed on chine guard. AGO 5244A Figure 143. Damaged coaming and cap. Figure 11,4. Graving piece installed on coaming. c. Cut graving piece from repair stock. Finish graving piece to fit repair area. d. Coat all contact surfaces with glue and install graving piece in repair area. Secure at each end with galvanized finishing nails (fig. 144). e. Install new section of cap. Cap should be secured to graving piece near the center, rather than at each end, to prevent splitting. AGO 6244A THREE TYPES OF GUARDS Figure 145. Damaged guard and repair. /. Paint graving piece and cap to match existing surfaces. 141. Repairing Damaged Guard or Rub Strake The damage to a guard or rub strake is usually amidships and is caused by laying against a piling, bulkhead, or dock in rough water without the proper fenders. Contact with another vessel can also splinter or break out a section of guard. a. Repair of Damaged Guard. ( 1) Locate nearest fastenings. (2) Make cuts within 3 to 4 inches of fastenings nearest limits of injury (fig. 145). BER RUB STRAKE DING Figure 146. Replacing canvas on rubber rub strake. (3) Make cuts with a fine-tooth saw at a 45-degree angle. Both cuts should run forward from outer face. ( 4) Remove fastenings carefully and retain damaged piece to serve as a pattern. (5) Cut new section full so it can be dressed down for proper fit. (6) Cut one end to a 45-degree angle. Place it under old guard to check accuracy of cut. (7) Take length measurement on outer face, and cut other end. (8) Hold the piece in place, if it is still full, and run a saw through the joint for a final fit. (9) Paint back of new piece and allow it to dry. Do not get any paint on end grain, as the joints will be made with waterproof glue. (10) Lay out fastenings so that two end fastenings are close to joints. To have the fastenings go through both pieces to tie them together would eventually cause the ends to split. (11) Install new section. (12) Dress piece, with ends glued and screws in and plugged, down to exact shape of old guard with a block plane. (13) Sand surface smooth in preparation for finish. b. Replacing Canvas on Rubber Rub Strake. On some vessels, the rub strake is made of canvas covered rubber. Repairs on this type rub strake are accomplished as follows: ( 1) Remove top and bottom molding carefully (fig. 146). (2) Cut only edges of canvas, at molding edges, from rubber portion the first time the rail is repaired. Do not try to separate the first covering of canvas from the rubber, but all later coverings should be removed. (3) Apply canvas glue to 6-ounce canvas and attach to rubber rub strake. ( 4) Tack bottom edge of canvas first. Stretch top edge and tack as shown in figure 146. Tacks should be placed far enough from edge of rubber so that when molding is secured in place it will stretch canvas evenly. ( 5) Thin the canvas cement with white gasoline and use thinned cement as waterproof coating over new canvas. ( 6) Replace molding if badly damaged. Duplicate original as nearly as possible. (7) Fasten molding with screws and plug screw holes with wood. 142. Repairing Damaged Plank A damaged plank can be repaired by cutting away the damaged section and installing a new section, securing end joints with butt blocks (fig. 147). a. Removing Damaged Section. (1) Mark plank for cutting, making marks square with plank. Note. Joints for new section must be at least three frame spaces away from nearest joints in planks immediately above and below damaged plank. (2) Drill starting hole at each end of damaged section and, using a keyhole saw, cut along marked line. (3) Remove fastenings and remove damaged section. If a fastening is difficult to remove, it can be cut flush with frame. b. Installing Butt Blocks. (1) Cutt butt blocks from oak of same thickness as planking. Butt blocks should be 1 inch wider than planking AGO 6244A DAMAGED PLANK STEP 1. REMOVE DAMAGED SECTION STEP 2. INSTALL BUTT BLOCKS STEP 3!. FIT, FASTEN, CALK, AND PLUG NEW PLANK Figure 11,.7. Repairing a damaged plank. and have a length of approximately 12 times planking thickness. (2) Coat butt blocks with bedding compound and clamp in position. (3) Fasten ends of existing planking to butt blocks with wood screws. Screw holes should be counterbored and plugged. c. Installing New Section. (1) Cut repair section from same material as original planking. Shape to obtain a light-tight fit on all sides. (2) Bevel outer edges to allow for calking. (3) Locate any fasteners that were left in frames and mark their positions on repair section to prevent installing new fasteners at those locations. (4) Fasten repair section to frames and butt blocks with wood screws. Screw holes should be counterbored and plugged. Note. If considerable bend is required in repair section, use shores or braces to obtain bend, and secure ends to butt blocks with flat head bolts rather than wood screws. (5) Paint seams, then apply calking and seam compound. Sand surface and paint to match existing planking. 143. Repairing Punctured Plywood Punctured plywood can be repaired by replacing damaged section with a repair section held in place with a backing piece. a. Cut out damaged section. Make a square cut to aid in fitting repair section. b. Cut back piece from plywood of same thickness as original. Backing piece should overlap repair area on all sides for installation of fasteners. c. Install backing piece behind repair area. Secure with wood screws and waterproof glue. d. Cut and shape repair section to provide a tight fit on all sides. e. Coat outer face of backing piece, inner face of repair section, and edges with glue. f. Install repair section and secure with wood screws. Fill cracks or voids with glue. g. Sand and paint repair area. 144. Repairing Broken Frame Broken frames can be repaired by installing a sister frame. The sister frame should be slit to relieve stress (fig. 148). a. Cut sister frame from clear, straight grained oa:k. Sister frame should be same width and thickness as broken frame and -of sufficient length to overlap at least two planks on each side of break. b. Make a cut lengthwise, using a rip saw, through center of sister frame, to a point not less than 4 inches from end. c. Steam sister frame for bending. d. Install sister frame as shown in figure 148. Secure planking to sister frame with bronze stove bolts with bolt holes counterbored and plugged. It is not necessary to fasten sister frame to broken frame. AGO 5244A PLANKING SPRUNG OFF SAW CUT RIPPED OR SLIT SISTER FRAME SISTER FRAME INSTALLED ALONGSIDE OF OLD FRAME Figure 11.8. Repairing a broken frame. Note. If planking has sprung away from broken frame, it should be forced in place with shores and braces. e. Soak sister frame and fractured area of old frame with wood preservative when sister frame has dried. f. Clean and recalk plank seams in area of damage. 145. Patching Main Frame Because a main frame would be exceedingly difficult to remove from a vessel, it is recommended that breaks be repaired by patching as follows: a. Cut and shape a sister frame to match existing frame. b. Cut a backing piece from straight-grained, l-inch thick oak, long enough to extend well above and below damaged section. c. Steam sister frame for bending, if necessary. d. Clamp sister frame and backing piece in place on each side of broken frame. e. Secure with %-inch bolts, staggered at 8-inch intervals. Use brass bolts up to 1 foot above waterline. Galvanized bolts can be used above this point. 146. Patching Batten A cracked batten can be repaired by patching (fig. 149) as follows: a. Cut a new batten to fit between frames over damaged batten. b. Fasten new batten to frames with metal angles and to existing batten with wood screws. 147. Repairing Bulkhead Repair damaged sections in wood bulkheads as follows: a. Remove all fasteners and obstructions from damaged area. b. Determine exact extent of damage and mark it clearly. c. Obtain a copy of vessel plans, if possible, to pinpoint any wiring or piping systems that could be in the area that is to be cut. d. Cut out damaged section carefully so that it can be used as a template. e. Pry off cutaway section, using a chisel and hammer where it is glued to frames. f. Dress all splinters and old glue from frames, and plug old screw holes. PLANKING (OR HULL) CRACKED BATTEN Figure 149. Patching batten. AGO 6244A g. Lay out and cut new piece r.nd check it for proper fit. h. Mark on new piece the location of backing members to which fasteners will attach. i. Mix appropriate amount of glue, and ap ply a coat to all sections that will make contact with fitted piece. Section Ill. 148. General After hull has been planked and all seams smoothed, a most important job of calking must be accomplished. This is not a difficult task, but one that should be performed with care and a thorough understanding of the principles involved. A good method of calking cannot be mastered by reading a book but must be obtained through gaining necessary experience to prevent mistakes. Following correct procedure of established methods can aid in acquiring and developing good calking techniques. 149. Calking Tools There is a number of sizes and sets of calking tools available for the very professional job, but only a few common types are required to perform the necessary calking operation (fig. 150). Some of the more common types are listed below. n. Calking !Ton. A good quality calking iron is determined by size needed for a particular job. No. BB, Crease, %2 inch thick, and No. 0, Crease, ~·) 1; inch thick are commonly used. b. C(dk£n.r1 Mallet. An ordinary wooden mallet can be used, but a regular calking mallet is preferred because the calking mallet has less bounce and is sturdier. c. Seam Brush. The seam brush used should be a narrow, stiff bristled brush, permitting easy access of bristles into seams. d. Calking Wheel. The calking wheel is a handle with a wedge-shaped wheel. It is used to open a seam wide enough for calking and to roll cotton wick into place in seam. 150. Calking Principles and Procedures ·n. Prepnr-ing Seams. Before calking starts, seams must be prepared by painting with a AGO 5244A j. Tack new section in place. k. Drill holes through new panel for fasteners using an electric drill with a counterbore attachment. l. Install screws with hand screwdriver. m. Sand and finish new piece to match surrounding surfaces. CALKING seam brush and thick paint. Start calking while paint is wet, so that paint will cause cotton to swell and bind, thus adding to its life. Figure 151 shows a cross section of a typical calking seam. Note that the planks meet tightly, woodto-wood on the inside, with calking cotton filling about one half the seam and calking compound nearly filling the rest. If the compound were flush with outside of planking, it would squeeze out considerably as the wood swelled. b. Ca.lking Planks Gr-enter than % Inch Thiele. Calking is first driven in lightly in short bights. Bights should be 1% inches to 3 inches long, depending upon width of seam. The wider the seam, the shorter the bights, so that more cotton is driven in. One secret of a good calking is the proper way in which the tool is held €§§~--:~"" ., __11{ SEAM BRUSH FiguTe 1.50. Calking tools. INSIDE HULL OUTSIDE HULL SEAM COMPOUND Figure 151. Typical calking seam. Notice in figure 152 that the iron is held between the thumb and second finger of the left hand, while the extended first finger guides the strand of calking and controls the size of the loops. The hand is under the iron, palm upward, and the strand is always ahead of the iron. Let the iron lie loosely in the hand, with only the fingers guiding it. Tuck cotton in bights by light blows for several feet, then start driving it in. Even though the edge of the iron is slightly curved, it should be held square with the work and not rocked forward or backward, as this will cut the cotton. Drive the cotton in with even, heavy blows if the planking is mahogany.. If the planking .is a softwood, such as cedar, use lighter blows. Drive the calking into a tight bunch, or rope, about halfway into the seam. When the wood swells, the cotton m:;~.kes a continuous groove in the sides of the stem that keeps it from coming out. Watch the seam aliead. If it widens, more calking must be forced in; as it narrows, it is thinned out. Try to calk evenly. The force with which it is driven should be uniform, even though there is more cotton in some places than in others. c. Calking Planks Less than % Inch Think. Where the planking is less than % inch thick, the calking iron cannot be used. Instead, the calking is done with a calking wheel, and candle wicking is used instead of regular cotton. The wicking is laid straight along the seam. It is rolled into the seam by pulling the wheel ~long, not by pushing under pressure. The planking seam can be tight outside as well as inside. The wedge-shaped edge of the calking wheel can be used to open the seam by running it along the seam before putting in the wicking. d. Painting or Paying and Filling Seams. Once the calking is in, the seams must be painted or payed with the seam bnsh, and then filled with seam compound. There are two kinds of compound, one for deck seams and the other for hull seams. They are elastic and stay flexible for a long time. Note. Do not use putty. The linseed oil soaks into the wood, leaving the putty hard, dry, and inflexible. Using a putty knife, fill the seams with compound to somewhat below the surface of the planking to allow for swelling. CORRECT WAY TO HOLD THE IRON AND TUCK THE COTTON Figure 152. Calking procedure. Section IV. BEDDING COMPOUNDS 151. General Fortified bedding compounds should be used on frame and stem ends, beneath guard rails, moldings, and armorplate after the intial preservation treatment, and on all faying surface> where watertightness is mandatory. 152. Application Bedding compound should be applied heavily, with the resulting squeeze-out sufficient to insure that no voids remain between faying surfaces. Comb spreaders, with a tooth length twice the intended thickness of the compound AGO 5U4A layer, and with a space between adjacent teeth along the coated surface, will, in most cases, equal to the intended thickness of the compound insure that some of the compound remains layer, are helpful for correct application. after the faying surfaces are fastened. Strands of cotton wicking, laid intermittently Section V. PRESERVING AND FINISHING WOOD SURFACES 153. General Preservatives are applied on wood surfaces in order to protect the surface from rot and deterioration. Painting, which aids in keeping damaging elements away from surfaces, is a form of preservation. The degree of painting to be done is dependent upon the amount of repairs made, the extent of paint deterioration, and the general appearance of the vessel. All sections to be renewed should be treated with preservatives and painted, as specified herein, according to their particular location. 154. Preparation of Surface To insure that the paint finish will be longlasting and uniform, the surface to be painted must be prepared properly. Surface preparation should be accomplished by cleaning, sanding, preservative treating, priming, and glazing. a. Cleaning. Remove oil and grease from wood, canvas, and aluminum surfaces with naphtha, Military Specification MIL--N-15178. Remove dirt and dust with detergent and fresh water, using brush or lint free cloth. Rinse with clean, fresh water. Dry thoroughly before sanding. b. Sanding. Sand wood lightly to a hard, smooth surface, using garnet paper of suitable grit. Sand canvas deck surfaces carefully so that fabric is not exposed or cut. Remove all sanding dust with a brush or cloth dampened . with turpentine. c. Preservative Treating. After completion of all shaping, boring, and fitting, treat new repair wood by dipping, spraying, or brushing with wood preservative, Military Specification MIL--W-18142, and as follows: Warning: Do not permit smoking, welding, or other sources of fire near treating area or treated material for a drying period of at least 24 hours, as material is flammable. AGO 5244A Caution: Do not treat exterior surface of bottom planking below the painted waterline. Such treatment would adversely affect the adhesive qualities of the bottom paint. (1) Allow treated surfaces to dry for 48 hours before painting. (2) Treat all faired and cut surfaces of plywood with varnish or preservative prior to installation. d. Priming. Apply first coat of paint, thinned with 1 pint of boiled linseed oil to each gallon of paint, on all wood surfaces, except exterior surface of bottom planking below painted waterline. • e. Glazing. After primer coat is dry, fill cracks, depressions, and open seams with putty. After putty dries, sand surface to a smooth finish and wipe free of dust prior to painting. 155. Preparation of Paints Prepare paint in accordance with manufacturer's instructions for the type used. When thinning is required and manufacturer's specific instructions are not available, the following instructions will be adhered to: a. Cellulose Nitrate Dopes. Thin cellulose nitrate dopes, Military Specifications MIL-D5552, MIL-D-5554, and MIL-D-5555, by mixing with thinner Federal Specification TT-T266, as follows: (1) Brush application. For brush application, proportions will not be more than one part thinner to four parts dope, by volume. (2) Spray application. For spray application, proportions will not be more than one part thinner to one part dope, by volume. b. Enamels. Thin specified enamles by mixing with appropriate thinners as follows: (1) Thin enamels, Military Specifications MIL--E-5557 and MIL--E-7729, for brush and spray applications using the criteria listed in (a) and (b) below: (a) Brush application. Mix approximately one part thinner, Federal Specification TT-T-291, with four parts enamel, by volume. (b) Spray applicat?:on, Mix approximately one part naphtha, type 2, Federal Specification TT-N-97, with four parts enamel, by volume. (2) Thin enamels, Military Specifications MIL-E-1264 and MIL-E-1265, by mixing with thinner, Federal Specification TT-T-291, using thinner only as required. (3) Thin enamels, Federal Specifications TT-E-489 and TT-E-506, by mixing approximately one part thinner, Federal Specification TT-T-291, with four parts enamel. c. Paints. Thin specified paints by mixing witlr appropriate thinners as follows: (1) Thin paints, Military Specifications MIL-P-698, MIL-E-699, MIL-P2934, and MIL-P-15123, by mixing with thinner, Federal Specifiication TT-T-291, using thinner only as required. (2) Thin paint, Federal Specification TTP-102, by mixing with thinner, Federal Specification TT-T-291, or with turpentine, type 2, Federal Specification TT-T-801, using thinner or turpentine only as required. (3) Thin antifouling paint, Military Specification MIL-P-15931 or MIL-P19451, after completion of mixing procedures as outlined in paragraph 157b(1), by adding one part thinner, FSN 8010-597-5251, to four parts paint and mixing thoroughly. Note. Do not thin more paint than required for immediate use. d. Lacquer. Thin lacquer, Military Specification MIL-L-7178, as follows: (1) Mix lacquer with thinner, Federal Specification TT-T-266, using minimum amount required to thin adequately. (2) To reduce blushing, add thinner, Military Specification MIL-T-6095, to solution, using minimum amount required. 156. Application of Paint Paint should be applied under favorable weather conditions (no rain or dampness), with temperatures above 50°F (10°C) and below 100°F (38°C). To keep work dust free, avoid painting on windy days. A void painting in direct sunlight, where practical. a. General Procedures. The following procedures are for guidance. See Chapter 16 for detailed painting instructions. ( 1) Remove all movable deck gear and equipment from vessel prior to painting. (2) Cover machinery and fixed equipment with drop cloths to afford sufficient protection from sanding, dust, and paints. (3) Paint all horizontal and vertical surfaces of superstructure. ( 4) Paint all deck and cockpit surfaces, including fixed equipment and deck machinery. ( 5) Paint topsides· down to boot top. (6) Paint bottom and boot top, in that order. (7) Paint interior, following same order, by painting overhead surfaces first, then vertical surfaces, and then decks of fiats and bilges. b. Precautions. Due to the flammable and toxic characteristics of most paints and solvents, the following safety precautions will be adhered to when painting. ( 1) A void prolonged skin contact, especially if skin is broken or scratched, by wearing snug clothing and gloves. (2) Avoid excessive inhalation of fumes by maintaining adequate ventilation throughout the painting process. (3) Keep all flames or spark-producing equipment away from paint area. ( 4) Seal all containers after use and remove to paint stowage area. c. Touchup. Touchup or spot painting will be performed when less than 50 percent of paint surface or paint system of a major area AGO 5244A has deteriorated to the extent that the underlying paint or structure is no longer protected. When required, touchup will be accomplished, as necessary, to afford maximum protection against deterioration and to maintain a good appearance. For best results, apply final coat over area after initial touchup dries. d. Major Pa'inting. Major painting will be performed when more than 50 percent of the paint surface or paint system of a major area has deteriorated to the extent that the underlying paint or structure is no longer protected. The 50-percent failure stipulation applies when several separate damaged areas add up to more than 50 percent of total surface, and when the damage is concentrated in one area. When required, major painting will be accomplished as follows: (1) Apply paint in even coats and brush out well. Caution: Thick, uneven coats will blister, crack, or peel. (2) On surfaces where more than one coat is required, sand lightly between each dried coat with garnet paper, Federal Specification P-P-121, and remove dust with brush or cloth dampened with turpentine. (3) Allow at least 24 hours drying time between coats under good weather conditions, and 48 hours or more when weather conditions are less favorable. 157. Preparation and Application of Special Paints Special procedures are necessary for the preparation and application of certain paints in order to obtain the full benefits of their designed use. a. Preparation of Bottom Exterior Surface on Wood Vessel. ( 1) Immediately after haul out, remove all barnacles, marine growth, and foreign matter by scrubbing bottom thoroughly. (2) Rinse with fresh water and allow to dry thoroughly before sanding. (3) If old paint is in good condition, proceed as follows: (a) Sand surface to a smooth, hard finish, using garnet paper, 0 to 80 grit. (b) Feather edges of exposed or scuffed areas. AGO 5244A (c) Glaze seams, screw heads, and depressions, as necessary, with required putty. (d) Sand surface to a smooth finish and wipe free of dust after putty dries. (4) If old paint is in poor condition or is of a type that is known to act unfavorably to antifouling paint, remove all such paint and sand surface to a smooth finish. Warning: Most antifouling paints are toxic and necessary precautions must be taken against breathing dust when sanding, to avoid toxic effects. (5) After sanding plywood surfaces, apply thin coat of sealing varnish, Federal Specification TT-V-119, to prevent reaction of antifouling paint with plywood binder. Note. Varnish sealer coat is not needed prior to applying antifouling paint to plasticfaced plywood. b. Preparation and Application of Antifouling Paint. (1) Preparation. Antifouling paint can be mixed either by hand or by mechanical mixer. The following procedures will be adhered to when mixing by hand. (a) Separate vehicle from pigment by pouring vehicle into a clean can. (b) Break pigment with a paddle. (c) Slowly add vehicle to pigment while stirring. (d) Stir thoroughly until completely blended. Note. A longer period of mixing is required to bring all pigment into suspension in antifouling paint than is required with most other types of paint. (e) Thin paint in accordance with procedures outlined in paragraph 155c (3). (2) Application. Flow paint on evenly at at full body using brush in same manner used to apply enamel and the following: (a) Apply two coats on exposed wood, allowing 12 hours drying time betweeen coats. (b) Sand first coat lightly prior to application of second coat. Note. One coat is usually sufficient when applied over old paint in good condition. (c) Burnish surface lightly with abrasive paper, Federal Specification P-P-101, after final coat is thoroughly dry, to insure maximum protection and service life from the paint. Note. Step (c) above is not mandatory when impractical. c. Preparation and Application of Aluminum Paint. (1) Preparation. Prepare quantities of lacquer and pigment for mixing aluminum paint in exact proportions according to the following: (a) Mix 1 gallon of lacquer, Military Specification MIL--L--7178, to 12 ounces of pigment, Federal Specification TT-P-320. (b) Add small amounts of lacquer to pigment, stirring thoroughly between each addition. (c) Add lacquer-pigment mixture to balance of lacquer after pigment is dispersed and stir. (d) Thin, as required, using approximately 1 gallon of thinner, Federal Specification TT-T-266, adding small amounts of thinner to mixture and stirring between each addition. (2) Application. Prior to applying, strain final mixture through a 35-to 40-mesh screen to remove unmixed particles. Apply, using brush or spray, in same manner as for conventional paints. d. Use of Polysulfide Synthetic Rubber on Wood. To provide leakproof coating on planked hulls or any wood surfaces containing cracks, use polysulfide synthetic rubber as follows: ( 1) Perform all necessary repairs, and smooth surface with sandpaper. (2) Clean and dry surface prior to painting. (3) Coat surface with six coats of polysulfide synthetic rubber coating, following manufacturer's directions for catalyzing, mixing, and application. ( 4) Use coating, when necessary, in seams on decks and around hatches and cabin house joints. AGO 6244A CHAPTER 5 STEEL HULL REPAIR Section I. GENERAL INFORMATION 158. General The quality of steel hull repairs must be first class in every respect and if any portion of the repair is found to be defective, whether partially or wholly completed, it will be removed and satisfactorily replaced. Repairs or alterations of steel hulls will be accomplished by experienced fitters and welders and will conform to U.S. Coast Guard regulations and American Bureau of Shipping standards. Preparation of the work, including cutting, forming, and fitting-up, will be to acceptable close tolerances to minimize the warping and distortion caused by heat and shrinkage of the welding process. Welding grooves will not be larger than required to develop the strength of the joints. Welds will be made with electrodes as specified for use in the original structure or part and will be kept to the minimum dimension and weld size, commensurate with the design of the repair. Care will be exercised to hold the form and dimension of the part of the hull being repaired or altered by the use of shores, bracing, clamps, or strongbacks. Welds in hoisting or lifting structure will be inspected by nondestructive test methods using radiographic inspection for butt welds and magnetic particle or dye-penetrant inspection for other type welds. 159. Hull Inspection When a vessel enters a drydock or marine railway for hull repairs, the amount of work necessary is determined after an inspection or survey is made. In cases of damage resulting from collision, grounding, or other mishaps, the presence of broken, buckled, torn, or punctured plates can look very difficult and expensive to repair. However, if it is a fairly new and sound vessel, the damage can be repaired with a single AGO 5244A plate or patch. If it is an old vessel, it is absolutely necessary that a thorough inspection be made to insure that the damage does not extend beyond the visibly affected area. The shock of collision or upward pressures of grounding will communicate itself throughout the craft in a disastrous fashion. All rivets and welded seams should be carefully inspected over a larger area than the actual damaged section. All heavy fittings, such as inlet and overboard valves that are welded directly to the shell near the point of damage, should be tested to assure that there are no cracked welds or casting, and that the seating is undamaged. 160. Types of Hull Repair Since the adoption and perfection of arc welding, the riveted steel hull is becoming a thing of the past. An exception to this is the welding of small vessels which have thin gage steel hulls. The use of arc welding oii vessels with thin gage steel hulls is very difficult as there is a possibility of burning holes in the thin gage steel. In addition, the heat from the weld arc will distort, wrinkle, or buckle the thin steel, which will necessitate considerable fairing or smoothing out and possible replacement. Some of the repairs that can be performed on steel hulls are as follows: a. Imperfections in thin gage steel can be smoothed out with a fiber or rubber mallet and a dolly block, which is a heavy flat piece of steel used to back up the area to be tapped smooth. This process usually required two men, one inside the hull to tap the inperfection in place and the other outside the hull to hold the supporting dolly block. b. Ripples or bulges that cannot be corrected by hammering out or fairing could possibly be corrected by heating and cooling. Heating and cooling can shrink the metal enough to pull the metal fair or smooth. c. Small imperfections that cannot be faired or hammered out can be cleaned and filled with lead, plastic or epoxy compound, and dressed smooth. d. Strengthening members, such as frames and stiffeners, can be repaired by the use of doublers welded to the weakened or broken sections. e. Seams that have cracked or separated can also be strengthened by a doubler and riveted or welded in place. f. Portable deck supports and access ladders are held in place by pins and bolts to permit easy removal. These pins and bolts should be checked frequently for wear or weakening and, if necessary, replaced. g. Welding is considered the more expedient, inexpensive and permanent over-all methods of repair of steel hulls. 161. Causes For Repairs There are many causes for repairs. The most common causes are corrosion, grounding, collision, and internal or external explosion. Corrosion caused by electrolysis or galvanic decomposition is a constant threat to vital parts of the external structure of a hull such as the rudder, propeller, rivets, hull fittings, and steel plates. The proper use of primers, paints, zinc or magnesium anodes, and frequent inspections are the best remedies for corrosion. a. Electrolytic Cmorosion. All vessels that contain metal are subject to damage by electrolytic corrosion or electrolysis. Electrolysis is a chemical reaction whereby a voltage (potential) is generated causing electrical current to flow between two dissimilar metals which are submerged in a solution of electrolyte. Electrolyte is normally a manufactured acid but in this case water is the electrolyte. This chemical reaction exists naturally where two underwater metals of different chemical composition are connected electrically which causes the wasting away, or going into solution, of one of the metals. An example of this is when a vessel's battery is connected between two underwater parts through error (fig. 153). The inspection and correction of stray electrical current will aid in the reduction of damage of electrolytic corrosion. U.S. Coast Guard electrical engineering regulations state that no switch or circuit breakers will disconnect the grounded conductor of a circuit, unless the switch or circuit breaker simultaneously disconnects all ungrounded conductors. A fuse in the grounded conductor of a circuit can cause the flow of dangerous electrolyte current, sparks, or fire. Although a large flow of stray battery current will cause the most rapid failure of underwater metal, the most treacherous form of electrolysis is that which occurs when the current is supplied-lly the metals themselves. This takes place when unlike metals are connected and immersed in brine. Electricity is generated through the discomposition of two metals. Zinc or magnesium protector anodes are often used to prevent corrosion. For a more detailed description of the causes and control of electrolysis, refer to chapter 9, Control of Electrolysis. b. Grounding. When a vessel runs aground, much damage can be sustained, depending upon the sea bottom conditions, speed of the vessel, and the structural strength. If paint or protective coatings are scraped away, holes and dents are likely to be inflicted on the hull plates and frames, and a general weakening is suffered by the craft. Collision damage can usually be classed as minor or major after a close survey of the affected area. c. Explosions. Explosions, either internal or external, usually rip or tear away complete sections, seams, or plates. This type of damage is usually severe, depending upon the size of the blast and whether it was above or below the waterline. Repair is often hampered by inaccessibility or by jagged protrusions. Figure 153. Electrolytic corrosion. AGO 6244A Section II. REPAIRING STEEL HULLS 162. General To determine the exact extent of repairs to a steel hull, the first consideration should be given to the type of damage, the location of the damage, and whether it can be permanently repaired without the use of marine railway or drydocking. The more severe the damage, the less likely that on-the-spot permanent repairs will be practical. This is because there are usually limited amounts of materials on board, depending upon the size of the vessel and storage facilities available. Regardless of the extent of damage, some type of emergency repairs will be necessary to safeguard the vessel until a suitable anchorage is reached. 163. Repair Materials a. Types of Material. The greater part of the hull consists of mild steel. Wrought steel is used for parts, . such as sheathing and railing. Cast steel is used for parts, such as propeller shaft stays, rudder tranks, stern posts, and cleats. The various angles and beams are made of ferrous metals. The many different types of steels now available, plus the advancements being made with alloys and steels, are, in effect, making vessels lighter, stronger, and more resistant to the elements. The particular repair material that is used on any vessel will depend greatly upon the type, size, and general construction. In each case, the repair material used should be the same as the material with which the hull was originally constructed, or an approved substitute of equal quality. b. Identification of Materials. A general knowledge in the identification of materials is Figure 151,. Common structural members. AGO 5244A 179 a valuable guide to an expedient repair. The angles and beams used in the construction of a vessel have forms of cross section throughout their length which lead to strength and rigidity in fabrication. Figure 154 shows a typical way of remembering the shapes of common structural members. JOZILTCH is a term used for the arrangement of different structural members in this order. Common angles and shapes used for hull structures are listed in table X. Many metals can be identified by color, texture of machined and unmachined surfaces, and the studying of chips produced with a hammer and chisel. The various types of irons and steels produce sparks which vary in length, shape, and color when held lightly against a grinding wheel. The wheel should be of the aluminum oxide type, which is hard enough to wear reasonably long, yet soft enough to retain free cutting properties. The peripheral speed should be approximately 4,000 feet per minute to produce good, short, bright sparks. The tests should be performed in well diffused daylight and against an ordinary background. In all cases, it is advisable to use standard samples of metals that have known composition so that these sparks can be compared with the material under test. The welder can identify various metals with the oxyacetylene torch by studying the melting rate, the appearance of the molten metals and slag, color changes during heating, and other manifestations developed by heat. A few of the identifying characteristics are described as follows: Table X. Common Angles and Beams Type Use Angle Bar_______________ Used for connections of plates to plates, when meeting at an angle and as stiffeners. Pipes____________________ Three grades, or weights, are the following: standards, used for systems of 150 pounds pressure or less and light structural work such as railings; extra strong, used for high pressures and stanchions; double extra strong, used where greater support is needed such as deck stanchions, machinery foundations. Flat Bar_________________ Various sizes, up to 6 inches wide inclusive. Used for straps, liners, tieplates, and where narrow plates are required. Zee Bar__________________ Used where necessary to rivet both flanges, also frames outside inner bottom bulk head stiffeners. I Beam__________________ Used for machinery foundations, bulkhead stiffeners, and deck beams. Bulb Angle_______________ Used for framing. The bulk edge eliminates sharp edges.Tee Bar_________________ Used for hatch cover supports and deck beam straps.Channel Bar_____________ . Used for deck beams, stiffeners, and frames. Provides much greater support than angles. H Bar___________________ Beam designed with wider flanges and web, and siructurally heavier than the I beam. (1) Appearance. (a) Gray cast iron. The unmachined surfaces are very dull gray in color and, probably, somewhat roughened by the sand mold used in casting the part. Unmachined castings can have brighter areas where rough edges have been removed by grinding. (b) Malleable iron. The surface is much like gray cast iron but the dull gray color is somewhat lighter. It is generally free from sand. (c) Wrought iron. Its appearance is the same as that of rolled low-carbon steel. (d) Low-carbon steels. The appearance of low-carbon steel depends upon the method of its treatment rather than its composition. 1. Cast. This steel has a relatively rough, dark gray surface, except where machined. 2. Rolled. This steel has fine surface lines which run in one direction. 3. Forged. This steel is usually recognizable because of its shape, hammer marks, or fin. (e) High-carbon steels. The unfinished surface is dark gray and similar to other steels; however, these steels are usually worked to a smoother AGO 6244A finish than the less costly low-carbon steels. (f) Steel forgings. Steel forgings have a smooth surface and, if the forgings have not been finished, fins, caused by metal squeezing out between the forging dies, will be evident. If finished, the area from which the fins have been removed will be noticeable. These forgings, unless properly cleaned, will be covered with a reddish-brown or black scale. (g) Alloy steels. Drop alloy forgings have the same appearance as other drop-forged steels. Many of the alloy steel products are surface machined. (h) Cast steel. The surface is brighter than cast or malleable iron and sometimes contains small bubblelike depressions. ( i) Monel metal. Monel metal is light gray in color and dulls to a darker gray with age. (2) Fracture test. (a) Gray cast iron. Nick a corner of the gray cast iron with a chisel or hacksaw and break it off with a sharp blow by a hammer. The break will be short and the exposed surface will be dark gray in color. This color is caused by fine specks of graphite dispersed throughout the metal. Chips raised by a chisel break off as soon as they are formed. (b) Malleable iron. The central portion of the broken surface is dark gray with a bright steel-like band around the edge. Malleable iron, when of good quality, is much tougher than cast iron and does not break short when nicked. (c) Wrought iron. Wrought iron can be bent and is quite ductile. When it is nicked and bent to the breaking point, the break will be jagged. This iron has a fibrous structure and can be split in the direction in which the fibers run. It is easily cut with a chisel. (d) Low-carbon steels. The color is bright crystalline and is very hard to chip or nick. (e) High-carbon steels. These steels are harder and more brittle than lowcarbon steels and the fracture is whiter and has a finer grain. (f) Steel forgings. Forgings can be of low-carbon, high-carbon, or tool steel and the color will vary from bright crystalline to silky gray. When the specimen is nicked, it is harder to break than cast steel and has a finer grain. (g) Alloy steels. Generally, the alloy steels are very fine grained, and occasionally the fracture will have a velvety appearance. (h) Cast steel. The surface of the fractured area is bright crystalline and the steel castings are tough and do not break short. Chips, other than manganese steel, that are made with a chisel will curl up. Manganese steel cannot be cut with a chisel. ( i) Monel metal. The factured surface is crystalline and its color is similar to that of nickel. (3) Grinding wheel test. (a) Gray cast iron. A small volume of dull red sparks that follow a straight line will form close to the wheel. These break up into fine repeated spurts, which change to straw color. (b) Malleable iron. The outer bright layer gives bright sparks like steel. When the interior is reached, the sparks near the wheel quickly change to a dull red color. These sparks are much like those from cast iron but are somewhat longer and are present in greater volume. (c) Wrought iron. Straw colored sparks from near the grinding wheel will change to white forked sparklers near the end of the stream. (d) Low-carbon steels. Low-carbon steel gives off long white sparks, which are longer than those from cast AGO 5244A 181 iron; however, they show some tendency to burst into white forked sparklers. (e) High-carbon steels. A large volume of brilliant white sparks are given off. The sparks are whiter and spark more freely that those from mild steel. (f) Steel forgings. The sparks given out are long white streamers. Sparks from high-carbon steel are whiter than those from low-carbon steel. (g) Alloy steels. The various alloy steels produce characteristic sparks both in color and in shape. With practice, many of them can be identified by their sparks. (h) Cast steel. The sparks are much brighter than those from cast iron; for example, manganese steel gives off sparks that explode, throwing off brilliant sparklers at right angles to the original patch of the spark. (i) Monel metal. Monel metal produces short, wavy, orange streaks similar to those given off by nickel. (4) Torch test. (a) Gray cast iron. As it melts, a heavy tough ·film forms on the surface and the puddle is quiet and very fluid. When the torch flame is raised, the depression in the surface of the puddle disappears instantly, and the molten puddle solidifies slowly and gives off no sparks. (b) Malleable iron. The molten metal boils under the torch flame; however, when the flame is withdrawn, the surface will be found full of blow holes. The melted part will cool very hard and brittle, forming a white cast iron or chilled iron caused by the melting and rapid cooling. The outer steel-like shell will give off sparks under the torch; however, the center portion will not. (c) Wrought iron. Wrought iron melts quietly, with a slight tendency to spark. The melted iron has a peculiar slag with white lines and a greasy or oily appearance. (d) Low-carbon steels. The steel, when melted, gives off sparks but when the flame is removed, the steel solidifies almost instantly. (e) High-carbon steels. The molten metal is brighter than molten low carbon steel and the melted surface has a cellular appearance. (f) Steel forgings. Steel forgings spark when melted and the greater the carbon content, the greater the number and brilliance of the sparks. (g) Alloy steels. Steels containing a considerable quantity of chromium will display a greenishcolored slag on the weld or puddle when they are cooled. In general, the effects of the torch test depend upon the composition of the aJioy steel and must be determined by trial and experience. (h) Cast steels. The steel, when melted, sparks and solidifies quickly. ( i) Monel metal. Monel flows clearly without any sparks and, when cooled, forms a heavy black scale. 164. Repair Tools a. The condition of the tools, the correct tools for a particular job, and the proper use of them all reflect in the work that is done. A tool has to be used properly and also has to be kept in good working order. There is almost an unlimited variety of tools that can be utilized for hull repair. A knowledge of some of the more common types is a necessity to a job well done. A listing, showing some types of the more common tools and their uses, is shown in table XI. Table XI. Steel Repair Hand Tools Tool Use Ball-peen Hammer _____ A machinist's hammer, used to form rivet heads and as a general driving tool. A variety of weights are available. One lightweight and one heavyweight will be sufficient for most jobs. 182 AGO 6244A Table XI. Steel Repair Hand Tools-Continued Type Use Calipers --------------Inside caliper legs are curved outwards. Used to measure inside of holes, or circular openings. Outside calipers have the legs curved inwards. Used to measure outside diameters of circular objects. Center Punch ---------Used to mark or punch small centers, as a guide for drilling, burning, and/or layout of lines or points of measurements. Chisels ----------~----(1) Flat Cold Chisels: Used to chip flat surfaces and cut thin sheet metal. (2) Cape Chisels: Used to chip keyways, grooves, and holes for slats. (3) Diamond Chisels: Used to chip in corners or V-shaped grooves. (4) Round Nose Chisels: Used to rough out small concave surfaces or filleted corners. Chalk Line ___________ At least 25 feet of line, and some blue and white chalk are necessary items for laying out lines of work. C-clamps There are a variety of sizes. Two or three of the 2 inch and 6 inch are the most frequently used. Dividers A tool consisting of two hardened steel legs with a spring adjustment. Used to measure the distance between two points, transferring measurements, and scribing circles and arcs. Drift Punch or Pin ___ Has a tapered shank and is used to aline holes in flanges or plates, for rivets or bolts. Feelers ---------------A thickness gage. Used to measure the space between two surfaces. A very necessary tool when working at close tolerances. ~any sizes and degrees of cutting edges are used to smooth metal surfaces for fitting. Files ---------------Used to check vertical and horizontal surfaces. Level --------------- Used in many weights; used to drive wedges, wrenches, bent members of the hull. ~auls ----------------Use weight suitable for the job. Soapstone, used to mark steel. A soft natural stone. Leaves a clear white line when ~arkers -------------the proper thin edge is kept. ~icrometer ____________ A precision instrument used in close tolerance work; many variations for different jobs. Pocket Knife __________ A versatile tool for cutting, sharpening pencils, trimming gaskets and templates of light material. Rule ------------------A 6-inch scale is a very accurate measuring tool to within %4 inch; 6-foot scale is necessary for long measurements, but not accurate to more than lh6 inch. Screwdriver ___________ A necessary tool to have in different sizes. Scriber -~-------------A sharp pointed steel tool, used to mark lines on steel. Wrenches _____________ A full set of open end and box end are essential for a repairman to work efficiently. b. There are many other tools available for type of machine can make a roll or shape a the more detailed work. The tools listed in table plate. Shears are normally used for cutting flat XI are the one most frequently used and are steel material into various shapes. Planers are the basic tools for layout and minor jobs. In the used to bevel or taper the edges of plates and event of large damage where the vessel needs prepare them for welding or splicing. major structural repair, repair yards are usu ally well equipped to handle the most difficult 165. Repair Procedures repairs. The tools and machines necessary for The initial concern should always be the heavy work are designed to straighten, shear, inspection of the damaged area to determine roll, bevel, and do numerous other types of steel what repairs are necessary. Welded seams fabrication. One type of machine used for should be closely examined. If the hull is of straightening plates is known as the mangles. riveted construction, the rivets should be inThe mangles differs in design and construction spected for corrosion. The plates should be from the ordinary rolls. Intended only for flatexamined for buckles, cracks, or any other tening purposes, the mangles is made up of two signs of deterioration. When rivets, weld simultaneous rows of three or four cylinders. seams, or plates are found in need of repair or Regular rolls, in contrast with the mangles, are replacement, mark the damaged area with a suited to a variety of uses and are composed of distinguishable paint. Paint clearly on or near three cylinders, one upper and two lower. This the damaged area the exact part to be removed, AGO 6244A 183 replaced, or repaired and indicate boundary lines. In the event of plate damage, the plate should also have location markings which show the forward, aft, top, or outboard or inboard section of the vessel. Permanent markings should show the location, because when the same plate is heated, rolled, or goes through any form of repair, the markings can be removed. All sea connections should be closely examined for marine growth, fouling, deterioration, or any other signs of general weakening. To remove rust and marine growths from weld seams and rivets, it will be necessary to use sealing hammers, wire brushes, and scrapers. a. Bumping, Cropping, and Fairing. Hull repair involves many procedures. It is often practicable to remove plates, frames, floors, and stringers and to straighten and restore them to their original positions. When a vessel has suffered severe grounding, this repair is often performed on a larger scale. The more seriously damaged parts are removed from the vessel, marked for identification, and taken to the shop. The plates are straightened in mangles and, when necessary, rolled to shape in accordance with sets or templates. Frames, stringers, and other bars are repaired by hull repairmen. Seriously twisted pieces are furnaced; others are shaped with local heats; and some are restored to proper form in a cold press called a bulldozer. Small and badly bent plates, such as brackets and intercostals, are faired at the slabs with the aid of open forges and a furnace. Heating, pounding, and fairing causes treated parts, through thinning or drawing out, to increase in length, so that when they are returned to the vessel, cropping and trimming is necessary. Parts which are not considered damaged seriously enough to actually be removed from the hull are restored to shape by bumping. Heating torches, heavy mauls, shores and braces, an assortment of bars, levers, screwjacks, hydraulic jacks, and considerable brawn are needed for bumping. Typical examples of bumping are shown in figure 155. (1) Method A in figure 155 shows a deflected or stove-in hull being pulled out by the aid of a strongback assembly. A strongback assembly consists of a heavy channel pressing against two short pieces of channel away from the vessel, and a spanner bolt and nut. A hole is burned through the plate at the center of the hollow, and a second hole, in line with the first, is burned through the strongback assembly. A bolt is then passed through both holes. A workman outside the vessel will take up on the bolt with a long handled spanner or wrench, pulling the plate toward the proper position. The plate will probably have to be heated before it will become normal. When pulled out, the plate will not be smooth or flak until worked over with a maul and flatter, and heated several times. The hole will be filled with weld and ground smooth. (2) Method B in figure 155 shows both plate and frame damaged. Heads of bolts from the strongback assembly are welded to the plate. After both the frame and plate are restored to shape, the edges of the butt are veed or beveled on both sides of the plate, and the butt is filled by heavy weld. (3) Upon completion of welding, the plate should be bumped or faired to a reasonable smoothness. Inspection of any newly welded vessel will reveal imperfections. The best and most advanced fairing process is the use of numerous small heats, which are rapidly cooled. Fairing is accomplished by two men and required judgment, patience, and considerable practice. The two men, when convenient, should work at opposite sides of the bulkhead or deck. One man is equipped with a small heating torch and a six-foot straightedge. The other man is equipped with an air or water hose fitted with a nozzle and valve. One man makes frequent use of the straightedge in determining the fairness of the welded surface and the progress of the fairing. In a square or rectangular area, fairing will begin at an upper corner by making a small heat about the size of a quarter or half dollar. Care must be taken not to burn the plate. The torch is removed as soon as the spot assumes a red glow. Simul- AGO 6244A taneously, the man on the other side of the bulkhead directs a jet of air or water at the spot, rapidly cooling it. As the spot becomes black and cold, the next heat is applied 2 inches from the center of the first, and the same process is repeated, covering the plate with row after row of these small heats until hundreds of blackened spots give the appearance of a leopard skin. The effect of heating and rapid cooling is to shrink the material, so that the fullness or extra stock which causes the bulging of an area enclosed by welding is removed, and the plate becomes flat and taut. The number, location, and spacing of the heats is dependent upon the degree of bulge and the amount of shrinkage required; hence the success of the job hinges upon judgment and practice, as well as the smoothly coordinated efforts of the men performing the work. In cases where the fullness is extreme and is not entirely removed by the foregoing procedure, a small hole can be blown through the center of the bulge, and a torch, flatter, and maul used to work the metal toward this opening. As the extra stock is worked to this center, the hole becomes smaller and, when fairness has been attained, is welded up and ground smooth. b. Repair of Frames. Frames are the METHOD A METHOD B BULB ANGLE FRAME DEFLECTED OUTER PLATE WELDED BOLT HEAD INNER SHELL Z-BAR FRAME OUTER PLATE Figures 155. Bumping plates. AGO 5244A strength or skeleton members of the hull. When oen or more frames become weakened or break loose, a general weakening of the hull occurs at at that point or, in more severe cases, can cause hull collapse and sinking. The frames form a grid work to which the hull plates are fastened and in case of collision, grounding, or where there is a rupture in the plating and framework, close inspection of all surrounding welds and rivets of the frames is necessary. If the frame is bent or broken away from surrounding members but not twisted or severly buckled, it can be heated and, by using chainfalls, strongbacks, or mauls, forced back to its original shape. In cases where damage is extensive, the section can be cut away and a new beam fitted and welded in place using doubling plates or bars welded over the joints along the webs. Figure 83 is typical of a doubling bar welded to a frame at a break or buckle. c. Repair of Plating. Inspectors who examine a drydocked hull carry a hull test hammer with which they tap plates, rivets, and rusted-over welds or bolts. Should a loose rivet or bolt be tapped, the sound will be very distinguishable from that of a solid one. The tapping of the rivet or bolt breaks away scale and, if the disintegration of the metal is great enough, will allow the rivet or bolt to move. The removal of rusted rivets from a plate usually required redrilling rivet holes in the plate due to an enlargement of the hole caused by rust. Once the holes are properly redrilled, a larger rivet can be inserted. Plates which have undergone damage due to grounding, collision, or explosion require a different and more difficult repair. A template should be prepared for plates that are torn or ruptured to the point that a new plate would be the more economical. If the plate has suffered only minor to moderate damage, it can usually be repaired by bumping without removal. Bumping is accomplished wtih heating torches, strongbacks, chainfalls, mauls, and shores which are used for pulling a bent or buckled plate into proper shape. When the plate has been wrinkled and bent, and the need for removal is certain, it is then carefully marked as to the forward end, topside, and, if many plates are being removed at once, given a number. This number indicates the exact location on the hull for its replacement after straightening. For straightening, the plate is sent through a set of rolls or mangles. In case the plate should have any shape or roll added, a template can be constructed from the hull, and the plate rolled as needed. d. Emergency Crack Stopper. An emergency crack stopper (fig. 156) in vessel plating consists of a %-inch drilled hole and a weld overlay. The hole is drilled at the end of the crack. Because this is a temporary repair, no welding is performed on the crack within 1;2 inch of the hole. An overlay of one layer is applied to an imaginary extension of the crack. A weld overlay plate, 15 by 10 by 3 inches should be installed with the tapered end away from the drilled hole. An overlay is applied on both sides of the plate, if possible. To prevent stress concentrations, extreme care should be taken to fill craters and minimize arc strikes. After the overlay has been made, the crack can be chipped out and rewelded using the appropriate electrode for the plate material involved. e. Splicing-!oinery. The term splicing is the process of beveling or planing plates at points where two or more plates are joined. Beveling and planing, commonly called tapering, will permit fastening one plate under another with bolts or rivets, giving a smooth, level appearance when joined together. An example of splicing and joinery is shown in figure 157. This ilustration shows a riveted butt joining an overlap. The scarfed edges allow the overlapped plates to be pulled together to give less of an appearance of three layers of plates. This method retains strength as well as provides a smooth joint. The actual joining of the plates by rivets, bolts, or weld is called joinery. The f--cRACK DRILLED HDLE---J T WELD OVERLAY 3IN. BOTH SURFACES ~::::::m:::::n~~::c:c:::m:c;?--_l_ t------10 IN. ----+i t--------15IN. ---------+i Figure 156. Welding O?Jerlay and hole emergency crack stopper. joinery of plates by joggling is shown in figure 158. Joggling is acomplished cold with the aid of a joggling-machine with which a width of joggling, up to about 10-inches, can be obtained. Care should be taken so that the joggle does not acquire sharp bends which can result in cracks in the material. f. Scribing and Template Making. Scribing and the use of templates in steel repair are the bases for expedient and accurate work. Any mistakes in size or location should be found in the templates and corrected before expensive materials are cut and wasted. The time involved in doublechecking a template or scribed location line can well be compensated for if mistakes are found and corrected at this point. (1) Scribing. Use a pencil to mark steel only where a temporary location point is needed. For a permanent mark on steel, a sharp, hardened steel scribe should be used. This tool will actually cut a mark into the metal surface leaving a bright, clear line. Often a dark marker dye is applied to the steel before the line is scribed, to aid in seeing the line. Center punch marks are sometimes punched along these lines to locate centers or points of intersection or exact dimensions of length. Where greater tolerances are allowed and the steel surface is not of an extreme shape, a chalk line and center punch is often used. Points of location are measured and a center punch mark is placed at the exact length desired. A chalk line can be held taut between these points and snapped; the connecting line can then be center punched to establish a permanent line. These marks form the initial guideline for construction of templates. (2) Template making. (a) Templates are constructed of light wood, paper, metal, or wire. The more permanent templates are constructed of wood or metal. These help to standardize an operation which must be performed a number of times. Wire is usually used for shaping pipes or handrails and only shows the basic shape or bend. AGO 5244A ;;;;::::.:::--llll!!l!!ljjil!i!l!i SECTION A-A Pigure 157. Splicing and joining of plates. Paper, fiberboard, cardboard, and holds form well enough for a rea other light, inexpensive materials sonably accurate template to be are used extensively in repair work made. and are discarded after use. This (b) The finished template can be type of material is easily cut and taped to the base lines and fitted AGO 5244A ~o 0,, 0, b,, ',~1 ) Figu1·e 158. Joggling and joining of plates. together, giVmg the repairman a general picture of how the completed job will appear. Each template should be rechecked for fit and location before any material is cut. A method of scribing a shape from an object, such as the contour of a hull, to a template board, is shown in figure 128. There are four different types of template materials shown in figures 124 thru 127 with a typical example of how they are used or formed. Note. When using lightweight materials as templates, always over cut the steel at least 1;16 inch to leave enough excess material to allow for error in the template. It is better to trim off the material to fit than to be short of the desired amount. g. Welding. Welding of repairs is faster, more watertight, and cheaper than riveting because there is a reduction in amount of materials and labor, making it easier to repair. Newer Army vessels are mostly all welded construction. On vessels with riveted hulls, alterations are frequently made; and, because of the removal or relocation of plates and badly corroded or damaged rivets, there are often rivet holes left in the plates which have to filled by welding. Three methods of filling these unwanted holes are shown in figure 159. ( 1) The single plate hole can be filled as indicated in methods 1 and 2. Method 1 shows the use of a small piece of copper plate, which will be unaffected by the welding, backing up the hole. The hole can be filled by piling the weld above the edge of the hole and hammering the weld with a peening tool until the metal becomes flush with the surrounding surface. If there is an abundance of metal, it can be moved by a sander or a grinder. (2) The hole, as shown in method 2, is countersunk and a rivet is inserted and held in place while the space left by countersinking is filled by weld. The remainder of the rivet is cut flush with the surface, and the area thoroughly welded and finished. (3) In cases of double plates, as shown m method 3, the hole is countersunk and a smaller rivet is inserted in the hole. AGO 5244A WELDING ROD ~ COPPER PLATE .METHOD 1 METHOD 2 DOUBLE PLATES METHOD 3 ""'"'moe=Ill - TYPICAL FINISHING PROCEDURE Figure 159. Methods of filling and finishing rivet holes. This enables the weld to be applied to the total thickness. The rivet forms a partial filler and a backer in the hole, which reduces the amount of weld normally necessary. To finish this type, the same procedures which were previously outlined in methods 1 and 2 are used. h. Bolting and Riveting. Rivet holes must be punched or drilled in the new plate to receive the rivets. The diameter of the rivet hole must be about 'li_ 6 inch larger than the diameter of the cold rivet to allow for expansion when the rivet is heated. Punching rivet holes is usually accomplished by machines which can punch 1 to 12 holes at a time. When the new plate is ready for installation, it is bolted in place. Sometimes it is necessary to line up the rivet holes, or fair them up, by using a tapered pin (·drift pin); however, reaming is usually preferable. When these plates have been bolted up, the holes that could not be previously punched are drilled and reamed in place. Section Ill. PRESERVING AND FINISHING STEEL SURFACES 166. General the proper paints. This rather simple statement has been substantiated and found applicable not Successful prevention of corrosion on steel hulls is based upon one elementary principle; only to bottoms but also to topsides, decks, keep the water away from the metal by use of bilges, and other metal structures exposed to AGO 5244A marine environment. The key to the lasting quality of these paints on metal is in the preparation of the surface, the use of the proper primer, and the time between the application of the primer and the removal of dirt and rust. This time span should be kept at a minimum. Note. Colors and thicknesses of paints to use are outlined in chapter 16. 167. Preparation of Surfaces A paint job is no better than the condition of the surface to which it is applied. If the hull has old paint, it is essential to remove all loose, cracked, or blistered areas. Removal of old paint, rust, or any other foreign matter is of the utmost importance for the proper adhesion of the primer. Various types of paint removers are available. After they are used, the vessel should have a thorough washdown to remove wax which can be in paint remover. The use of blowtorches on a steel hull is not recom~ mended because the heat will burn off paint from inside as well as outside the hull. Also the inexperienced hand can overheat an area and cause warping or buckling, which will reduce tensile strength of the steel. a. Sanding and Sandblasting. If the hull plating is heavy enough, sandblasting can be the cleanest and most expedient way of preparing for the primer. Use a clean, sharp sand to remove mill scale, rust, and dirt. Remove residue by brushing or blowing it away with compressed air. Before sandblasting, all open machinery under repair will be completely covered and all operating machinery will be secured. Cover all overboard and inlet holes or ducts to prevent extensive damage to valve seats inside the hull. Sand or residue can also be drawn into pumps or other working parts of the vessel, causing minor damage or complete loss of equipment. Hand sanding with an abrasive, sandpaper, or emery cloth is recommended for relatively smooth surfaces of light gage material. A vibrator or circular-type sander can be used on large areas. A wire brush should be used to remove paint, rust, or other foreign matter from steel with pores or pits. b. PreseTvative Treatment. Bare metal surfaces should be coated with a pretreatment primer immediately after cleaning. The pretreatment primer is used as a bonding agent to provide temporary protection against corrosion. When correctly applied, the metal background is barely discernible through the wet film and the coating exhibits a greenish tint. If the coating turns white or bluish, moisture is indicated. If this occurs, stop the application, clean to the bare metal, dry thoroughly, and start over. The pretreatment primer should not be applied over paint, rust, moisture, or any other foreign matter. Mix the primer just prior to using, and if the mixture is more than 8 hours old, it should be discarded. Before the application of anticorrosion and antifouling paints, the primer should be allowed to dry for no less than 4 hours. Refer to TB 746-93-4 and chapter 16 of this manual for detailed requirements concerning application of primers. 168. Paint a. PrepaFation and Application Of Pctint. (1) Pr-eparation. Any type of paint, whether it be primers or final coatings, should be handled and used with properly operating equipment, good ventilation, and correct clothing. Driers and solv~nts are a part of paint composition, and the vapors are volatile and flammable. All welding, burning, and any other type of open flame or spark-causing equipment should be removed from the area. Paints also give off vapors that can produce physiological and toxic effects if inhaled for any length of time. Proper gas mask or explosion-proof type respirators should be used and clothing should be sufficient to minimize skin contact with paint or freshly painted surfaces. (2) Preparation of Paint. Paint should be thoroughly mixed with mechanical shakers or high speed stirrers to insure uniform dispersion of pigments. Thorough mixing is very important in the case of antifouling paint because, during storage, the copper pigments settle to the bottom of the container. In order to keep the pigments in suspension, antifouling paint should be restirred often while in use. (3) Application of Paint. Whether to use AGO 5244A spray, brush, roller, or dip procedure will depend upon the type of paint to be used, the manufacturers' specifica tions or directions for application, and the availability of equipment, such as scaffolds and compressors. Conven tional as well as vinyl paints should conform to standards as outlined in chapter 16. Major painting will be performed when more than 50 percent of the painted surface of a major area has deteriorated to the extent that the underlying paint or structure is no longer protected. The 50-percent fail ure stipulation applies when several separate damaged areas add up to more than 50 percent of the total sur face or when the damage is concen trated in one area. When only the finish paint on a major area has de teriorated and the underlying paint is in good condition, new finish paint can be applied over the intact under coats. Only conventional paint-covered surfaces. Vinyl or vinyl-alkyd paints should be used on vinyl or vinyl-alkyd paint-covered surfaces. Conventional paints can be used to coat vinyl-type paints where vinyl-type paints are not available. (a) Instructions for operaf'ing plast'ic paint spray equipment. The gun and equipment used for application of vinyl paints should have efficient traps for moisture and oil. Application should be made with continuous parallel strokes; each stroke overlaps the preceding stroke by at least 2 inches. Care should be exercised not to pause at the end of the stroke, because this will cause piling up at the laps and result in an uneven appearance, sagging, running, or a spongy film. The proper distance from gun to surface should be maintained as closely as possible. This distance should not exceed 16 inches. In tight corners and weld areas, the pattern should be reduced to a small oval to insure adequate coverage of these areas. A spray coat consists of one or more passes, AGO 5244A depending upon the paint, and should be considered as that amount of paint which is applied at one time and is just short of sagging, running, wrinkling, and orange peeling. Tank and line pressures are very important in the application of vinyls and will vary according to the spray equipment employed. Adjustments should be made to determine the pressures most suitable for obtaining a uniform fan with proper atomization. A fan which produces too dry a spray will result in a pimply surface with considerable deposits of spray dust. To correct this, the air pressure should be reduced and the paint pressure increased. Conversely, a fan which gives too wet a spray will give a film which can be splotchy, and sagging can result. To correct this, reduce the paint pressure and increase the air pressure. The spray pattern should be kept wet and the film continuous as the area is covered. If the fan narrows down or the paint starts to spit out of the gun, the nozzle should be removed and cleaned. Upon completion of work, the vinyl system should exhibit a relatively smooth surface finish. A pebbly surface can result from improper solvent balance or improper atomization and application of the spray coats. If this occurs, the pebbly surface should be removed to bare metal, unless an intact and smooth surface is reached that will provide a base for the proper build up of new system. (b) Touchup. Touchup or spot painting should be performed when less than 50 percent of the paint surface or paint system of a major area has deteriorated to the extent that the underlying structure is no longer protected. 1. Preparation. Deteriorated surfaces and adjacent areas of intact paint should be cleaned and adherent marine organisms removed, after which the edges will be feathered. If damage to the deteriorated surfaces extends to the metal, the bare surfaces should be conditioned. a. Prepared surfaces should have prime and finish paint applied in the number of coats and mil thickness prescribed m chapter 16. b. Vinyl paints should be used to touch up vinyl surfaces; vinyl,. alkyd paints should be used to touch up vinyl-alkyd surfaces; and conventional paints should be used to touch up conventional paint surfaces. When spot painting is necessary and proper paints are not available, however, either vinyl, vinyl-alkyd, or conventional paints can be used to touch up vinyl or vinyl-alkyd surfaces. Vinyl or vinyl-alkyd paints can not be used to touch up conventionally painted surfaces. Antifouling paint should not be applied over bare steel. (2) Active craft. Surfaces should be painted in accordance with chapter 16. Because of its copper content being corrosive to steel, antifouling paint should be applied only over anticorrosive primer or existing antifouling paint. Care should be ·exercised to prevent contact of antifouling paints with bare steel surfaces. Underwater surfaces should be touched up with primer and finish paint of the type and mil thickness specified in chapter 16. Remaining exterior surfaces should be touched up with two coats of primer and two coats of finish paint, and interior surfaces with one coat of primer and two coats of finish paint. (3) Craft in wet storage. All surfaces should be touched up as outlined in above, except for the finish paint which should not be applied to surfaces other than exterior underwater surfaces.' Surfaces that are subject to wear from usage will have an extra coat of primer applied. Under austerity conditions, use rust arresting compound in lieu of paint for exterior surfaces above water level. (4) Craft in dry storage. All surfaces should be touched up in accordance with above, except that no antifouling paint will be applied. b. Preparation and Application of Specinl Paint. · Preparation of special paints, the use of vehicles, driers, or thinners, and the application of special paints are determined by manufacturers' specifications. Normally, any deviation from the directions can cause the paint to lose its designed quality of adherence or durability. Each type of special paint requires specific treatment of the surfaces to which it is applied. Special paint also has precoats or primers which should be applied prior to the application of the paint. Special paints, their uses, their additives, and their primers are contained in TB 746-93-4. (1) Preparation of Surfaces. Cleaning of the surface and the correct primer coats for special paints are outlined in TB 746-93-4. Due to new types of paints which can be considered as special paint, it can be necessary to acquire the particulars on each individual application of special paints and on the primer that supplies the proper bond and protection. (2) Prepamtion and Application of Antisweat Paint. Vermiculite should be applied to the binder by compressed air. Particle velocity should be at a maximum and air discharge should be at a minimum to prevent premature setting of the binder by the airblast. The rate of flow shoud be even to obtain a uniform surface. Vermiculite should be entirely free from dust and fine particles to maintain the antisweat properties. Composite vermiculite binder mixture can be applied, if desired, as follows: (a) Apply the mixture with an air- AGO 6244A driven pump. The pump should be mixture be used within two days, alequipped with two air control valves though, it is possible to spray maand two air pressure gages, so that terials after one week of storage andpump airpressure and spray gun air still achieve fair results. Violent orpressure can be independently conprolonged agitation of the vermicutrolled. The mixture can also be aplite-emulsion binder combinationplied by using pressure pot spray will tend to break up the fragileequipment with fittings and material vermiculite granules, which will reoutlets no smaller than 1;2 inch. An sult in a spray mixture of inferiorinternal mix spray gun equipped quality.with a 1,4-inch inside diameter spray (3) Preparation and Application of Anti tip should be used. The gun should have a large back closing needle and fouling Paints. Antifouling paints will paint supply fitting of at least %not be applied over bare metal because the copper compound in this paint will inch. The spray hose should be suitable for using pressures up to 200 corrode the steel. Bare metal surfaces· psi. to be painted with vinyl antifoulingpaint will be thoroughly cleaned using (b) Prepare a thinner binder paint by naptha solvent, Type A of Militarymixing 20 gallons of binder, 71;2 galSpecification MIL--N-15178. Immedilons of mineral spirits, and 0.2 galately after cleaning, the surface willlon and 0.1 gallon of lead maganese be coated with a pretreatment primerand naphthenate driers respectively. meeting the requirements of Military (c) Add slowly a water solution of amSpecification MIL--P-15328. All sur monium oleate, prepared by dissolvfaces previously vinyl painted will being 3 pounds ammonium oleate soap cleaned with xylene conforming toin 40 gallons of fresh water, to form Federal Specification TT-X-916. Vinyl an emulsion. paint will be applied to the cleaned and (d) Prepare the ammonium oleate soap pretreated surface as soon as practicaby slowly adding 28 pounds of amble. Major application of paint will bemonium hydroxide to 100 pounds of by spray equipment. Touchup can betechnical oleic acid. Continuously done by spray or brush. Quantity andstir and mix the resulting soap until thickness of coats of antifouling paintthoroughly homogeneous. The soap will be as outlined in TB 746-39-4.should be stored in tightly sealed Vinyl-type paints will not be appliedcontainers to avoid the loss of amwhen the ambient temperature is lessmonia. These mixing procedures can than 40°F. (4.4°C.) or when the surbe best performed in a tank equipfaces show frost or moisture. All dampped with a high speed propeller-type surfaces will be thoroughly dried beagitator. The soap solution should fore painting. Painting will not bealways be added to the binder with done during rain or fog or in darknessviolent agitation to insure the forwithout adequate lighting.mation of a stable emulsion. At this (4) Prepomtion and Applicat'ion of Ce stage the emulsion can be stored for ment Coats. Where cement coating wasseveral weeks or longer if necessary. used to protect an area and less than (e) Stir 120 pounds of vermiculite into 50 percent of the cement coat has dethe emulsion binder mixture within teriorated, the damaged area will bea maximum of 2 days prior to the repaired with new cement. When thetime of application. This can best be damaged area has deteriorated in exaccomplished in a slow speed, padcess of 50 percent, all cement will bedle-type paint mixer, a dough mixer, removed and the area will be thorough or a small concrete mixer. It is ly cleaned and painted with zinc dust preferable that the complete spray paint as outlined in TB 746-93-4. AGO 5244A 193 The rivet heads should be covered Normally a cement wash coat or layers and a smooth surface obtained of cement coatings are used in double where no water can remain behind bottom tanks only if these are used for fresh water. Zinc dust paint is used the strakes. The coat of cement more often in these areas because this wash under the cement layer is material is more durable. A cement sometimes omitted. wash coat is pure cement mixed with (b) A layer of cement mortar is somewater to form a thin liqiud mass and times applied in the bilges and in is brushed or sprayed on the bare the holds where the margin plate is steel. The steel surface must be thoconnected to the shell. This is done roughly cleaned before the wash coat to hide the edge of the connection is applied. All rust, grease, oil, or angle bar, so that a smooth surface paint must be removed. In horizontal can be obtained. This is unnecessary work two wash coats of cement are apon welded vessels. plied; however, in vertical work three (c) Inaccessible corners are found in coats are applied. Properly applied, the fore-and-aft peaks, and if the the cement will give complete tight corner is small, it is filled with morcoverage. tar of the same composition as the (a) The treatment of the bottom in cement layer put on the bottom. If double bottom tanks depends upon the corners have a large content, the construction. For a completely they are filled up with coke or light welded bottom, two or three coats of stone. Thin cement mortar is poured cement wash will be sufficient. For between the stones and finished with thick cement mortar. The top a riveted bottom, one coat of cement wash and a thick layer of cement layer is finished obliquely, so that mortar made from two parts sand . the water can easily flow to the sucand one part cement are applied. tion strainer. AGO 5244A 194 CHAPTER 6 PLASTIC HULL REPAIR Section I. GENERAL INFORMATION 169. Plastic Hulls-General Reinforced plastic used in hull construction consists of fiberglass reinforcing material em bedded in a thermosetting resin. Thermosetting resins are liquid in their raw or initial state. They can be solidified by heat and/or chemical reaction and thereafter cannot be returned to their original state. Thermosetting resins are formed from one of three chemical compounds known as polyester, phenolic, and epoxy. Epoxy RUBBER GLOVES g is superior to polyester and phenolic in almost all properties, provided they are correctly ~;:::::::=:==::J It) procesed and cured. Fiberglass is a material SPREADING TOOL manufactured from strands of glass woven into HARDENER cloth and formed into mats or from irregular strands laid together to form mats called woven rovings~ This glass cloth, when combined with a thermosetting resin, provides a strong hull requiring minimum maintenance and hav ing excellent repair characteristics. 170. Tools and Materials GLASS MAT· a. Disk Sander. A 1,4-inch electric drill witha sanding disk attachment is a versatile tool forplastic hull repair. It can be used to removepaint, to scarf edges of areas for repair, and tofair in edges of patches. A resin-bonded alumi WOODEN SPATULAS num oxide or garnet grit disk should be used.Flint or sandpaper is not effective. b. Keyhole Saw. A keyhole saw is useful incutting away a damaged portion of the hull. c. Separting Film. Cellophane, polythylene,or polyvinyl alcohol film is suitable for use asa separating film. SEPARATING FILM d: Gloves. Rubber or polyethylene gloves INSTRUCTIONS should be used as protection against solventsand plastic dust. Figure 160. Typical plastic repair kit. AGO 5244A 195 amounts of bonding resins and hardener fibere. Respirator. Use a respirator recommended ous glass mats and tapes, and tools needed for for microsilicone dust. Keep an ample supply of changeable filters. application. Glass reinforced plastics can be repaired with the use of standard repair kits by f. Goggles or Face Shield. Goggles or face both experienced and inexperienced personnel. shield is necessary during all sanding and cutRepairs kits can be obtained for use from Armyting operations. Goggles provide more complete supply sources. The kits are obtained underprotection. Military Specification MIL-R-19907. A typical g. Glass Cloth or Mats. Patches for plastic repair kit is shown in figure 160. hulls require the use of glass cloth or mats. Mats for patching are usually thicker and 172. Safety Precautionseasier to work than glass cloth. The procedures and materials used in plastich. Resin. Of the three available resins (polyhull repair require that safety precautions beester, epoxy, and phenolic), epoxy has the most taken to avoid injury to personnel. The follow desirable properties for use in hull repair. ing precautions, in addition to those listed in Epoxy resins are excellent plastic-to-metal or chapter 1, should be adhered to:plastic-to-plastic adhesives. a. Provide adequate ventilation. i. Hardener. A hardener or curing agent must be mixed with the resin prior to use. The b. Do not allow silicone remover solvent to amount of time required for a repaired area come in contact with the skin. to cure will depend upon the hardener selected. c. Do not allow welding, burning, chipping, j. Resin Putty. Resin putty is a mixture of or any other spark-causing equipment to be resin and filler, thickened to the point where used in the area. it can be troweled into place. It is used for fill d. Wear snug fitting clothes, gloves, a facecover coats of resin and glass cloth. shield or goggles, and a respirator when sanding a plastic hull. 171. Repair Kits The most versatile method for repairing plase. Do not use electrical equipment in a wet tic hulls is with the plastic repair kit. These area, as the equipment can become grounded kits are equipped with instructions, measured and cause electrical shock. Section II. REPAIR PROCEDURES haul out and bottom wash down. Close examina 173. General tion of a damaged area can reveal that the Many deteriorating forces constantly act damage is not confined to the one noticeableagainst plastic hulls; of these, aging and abraarea. In the event of a puncture or hole, there sion are the most predominant. Whether the could be hairline splits caused by the transmitdamage is caused by aging and abrasion, tillg of stresses throughout the hull. A crushedgrounding, or collision, ~the repair procedure in section or area around a hole should be careis essentially the same. When damage is limited fully cleaned ofany foreign contamination, andto a small area, a repair kit will provide all all paint should be removed within 8 to 10material needed. If a large section is to be reinches of the damaged area. This will allow moved, a mold will be needed to retain the a good visual examination of the fibers to see if original contour of the hull. the damage extends outward. A bright light 174. Determining Extent of Repairs can be held on one side of the hull while the hull is inspected from the other side. The light will Periodic inspection for broken or exposed aid in showing crazed or cracked spots as well fibers, cracks, and crazed or cloudy spots is a necessary part of plastic hull maintenance. A as delaminated areas. On the hull mark the thorough inspection can be made only after extent of damage. AGO 6244A 196 DISC SANDER Figure 161. Dressing out scratch. 175. Repair of Scratch or Dent a. Clean damaged area thoroughly. b. Use tine sandpaper or steel wool to mar surface in and around dent or scratch after scratch or dent is cleaned. c. Take a small, sharp chisel or knife in case dimensions of a scratch are insufficient to insure that filler material will hold to surface, and carefully cut scratch on each edge at an angle, forming a V as shown in figure 161. This will remove any rough fibers on surface, and provide better bonding area. This cut will also provide a better opening to enable cleaning out of any foreign matter which could weaken the bond of the resin. d. Mix enough resin and hardener for the area being repaired and apply with a suitable spreading tool. e. Allow sufficient time for curing, according to the mixture used. Sand away any rough burrs and feather edges to surrounding surface. AGO 5244A 176. Filling Voids or Construction Defects In the repair and construction of plastic vessels, it can be necessary to fill voids, cracks, or imperfections. The most effective material to use for this type work is plastic putty. Plastic putty is simply a resin that is mixed with a filler and thickened to the point where it can be troweled and forced into place. The putty should be allowed to dry completely, or cure, before application of the cover coats of resin and cloth. Any imperfections can be easily sanded off. 177. Repairing a Punctured Hull The procedures for repairing a punctured hull can also be used for removing areas damaged by aging or abrasion. a. Cut away damaged area, removing all crazed, cracked, or splintered material. b. Scarf cropped area using a disk sander. Figure 172 shows a disk sander being used for cutting away damaged area and for scarfing. Note. When possible, cropped area should be scarfed and patching applied from inside the hull to minimize contour and resurfacing problems. c. Prepare hole for patch by attaching separator film and suitable backing plate opposite scarfed side. For large holes, backing plate should be molded to contour of hull. d. If glass cloth is to be used in preparing the patch, proceed as follows: (1) Apply a coat of resin around scarfed edge of hole. \ ~' J ( \ ...___ CUTTING SECTION OUT WITH DISC SANDER, SCARFING THE EDGE AT THE SAME TIME LAMINATES OF HULL CLOTH FIRST CLOTH LAYER (2) Cut a layer of glass cloth so it will overlap hole approximately 3 inches. (3) Saturate cloth with resin and apply to hole. ( 4) Apply a sheet of separator film and work cloth into all recesses, removing all air bubbles and excess resin. ( 5) Allow layer to harden. Remove separator film and dress edges with sander. (6) Prepare area for additional layer by roughing surface with coarse-grit MARKED AREA OF CUT HOLE SHOWING SCARFE~ ---___. EDGES WITH LAMINATES FOUR LAYERS OF CLOTH INSTALLED TO BUILD UP THICKNESS. SANO TO FINISH AFTER CURING. Figure 162. Repairing punctured hull. j.GO 5244A sanding disk. Apply additional layers as needed, with each additional layer cut to overlap next ring or a laminate visible in scarfed area. Final layer should overlap entire scarfed area by at least 3 inches. e. If patch is to be prepared from a mat or mats, proceed as follows: (1) Make up entire patch on a sheet of separator film, adding alternating layers of mat and resin until desired thickness is obtained. Mat should be cut to overlap hole 3 to 4 inches. (2) Apply another sheet of separator film and roll out all air bubbles and excess resin. (3) Paint scarfed area with activated resin. ( 4) Remove one sheet of separator film and apply patch, in poultice fashion, to scarfed side of hole. Make sure patch is worked into all recesses and no air bubbles are present. (5) Apply cover plate ov-er separator film to hold patch in place until it hardens. (6) Remove cover plate and separator film when patch has hardened, and dress edges with a sander. f. After patch has been built to proper thickness, hardened, and dressed by sanding, heat should be added to the surface to improve the quality of the patch. A 100-watt heat lamp, incandescent lamp with reflector, or any other comparable heat source will be satisfactory. Heat patch at 160° to 200°F. (71° to 93°C.) for 4 to 8 hours. 178. Repairing a Crack Along Chine Some plastic hulls develop cracks along the chines after several seasons of use. Such conditions are unsafe and should be corrected. An additional covering of glass cloth inside and outside the hull will help, but chances are that the hull does not have the proper stiffeners, and these should be added. The repair of cracks along the chine is closely related to the installation of additional stiffeners. Refer to paragraph 179 for complete details. AGO 6244A 179. Installing Bottom Stiffeners The addition of stiffeners can be necessary to prevent further separating or cracking of parts of the plastic hull. Stiffeners can be installed as follows: a. Clean area of weakness of all paints and other foreign materials, and apply coating of resin to area where stiffeners are to be fitted. b. Cut and fit addirtional stiffeners; tack them together so that, upon final installation, they can be placed in hull as a unit. c. Cover inside of hull with two layers of saturated 27-ounce woven roving (mat). While plastic is wet, set stiffeners in place and weight them with suitable weights. d. Turn hull over after inside is cured, and thoroughly clean outside with wax solvent, followed by scrubbing with detergent and water. e. Cover bottom, at least 6 inches past chines, with two layers of 10-ounce glass cloth saturated with epoxy resin; finish with three coats of epoxy resin. Note. Polyester resin should not be used on the outside coating, as it can peel if the hull is subjected to pounding from rough water. f. Cover stiffeners inside hull with three layers of saturated 10-ounce glass cloth, overlapping wood six inches or more all around and working well into corners to assure good bond. 180. Preservation and Finishing of Plastic Hulls In the preservation and finishing of plastic hulls, there are a number of paints and preservatives available. The use of epoxy in paints has become very extensive. This popularity has resulted from its durability and high resistance to marine growths. Epoxy paints come in two forms; one is a single liquid and the other, a two-part preparation. The single liquid paints carry the resin in a solvent that evaporates or oxidifies and deposits a plastic film with good protective qualities. The two-part paints are the resin and hardener, which have to be mixed in proper proportions before use and which have to cure after application. Epoxy is very expensive (nearly twice the cost of polyesters). Until specifications have been prepared and expoxy paints are stocked in the supply system, local procurement of epoxy paints is specified (4) Pot-life: 8 hours minimum at 77° F. as follows: a. Limited quantities can be procured for immediate use, not for stock. b. Epoxy paints can be used for color coating of repaired or newly constructed plastic or plastic-sheathed hulls. c. Standard vinyl paints should be used for plastic hulls which have been previously so painted and require freshening up of color coats. The epoxy paints purchased under the authority listed above should conform to the following general characteristics: ( 1) Air-drying. (2) Two-component material. (3) Basic resin of a known manufacturer. (25° C.). ( 5) Dry sufficiently to recoat in 4 to 6 hours. (6) Nonvolatile percentage by volume: 40 percent minimum. (7) Flash point over 80° F. (26.7° C.). (8) Approximately 2.0 mils dry film thickness per coat. (9) Spreading rate: 280 square feet per gallon minimum. (10) Favorable application by spray, brush, or roller. Note. Plastic hulls can be coated with one pretreatment coat, Military Specification MIL-P-15328, as shown in TB 746-93-4. Two coats of vinyl paint can be applied for color, but anticorrosive paint is not necessary. AGO 6244A CHAPTER 7 ALUMINUM HULL REPAIR Section I. GENERAL INFORMATION 181. General Aluminum allows available for marine use offer the advantages of reasonable strength, low weight, and strong resistance to corrosion. Compared with mild steel, both deflection under load is high and resistance to force is low in aluminum alloys. Future development in the use of light allows for vessel building largely depends upon the success of the aluminum industry in solving certain problems. The most pressing problem is determining a practical method of joining plates and sections of substantial thicknesses. 182. Inspection and Preparation of Hull After washdown of the hull and bottom and after removal of all foreign matter, a thorough inspection should be made. Every scratch, cut, gouge, or indentation should be noted and marked on the outside of the hull with a blue carpenter's pencil. The inside of the hull should be inspected for indentations or cuts visible at locations such as behind a stringer or plate or across a weld or rivet line. a. Determining Extent of Repairs. Every cut, scrape, gouge, or indentation should be thoroughly cleaned and rubbed with aluminum wool. All discoloration and rough edges should be removed. A discolored line will be a crack or break, and the inside of the hull should be checked to determine if stringers or butt plates supporting the hull plating are damaged. b. Types of Damage. Small dents or scrapes are usually minor. They can be caused by bumping into mooring buoys or pilings during change of tide or wind direction. Gouges or cuts are usually caused by hitting objects in the water such as submerged logs, pilings, and rocks. Cuts in aluminum can be caused by nails or bolts projecting from moorings or pilings. Section II. REPAIR PROCEDURES 183. General Repairs for aluminum hulls require preplanning and experienced personnel. Charts on the alloy of the aluminum to be repaired should be consulted. The recommended type and kind of welding should be followed. Rivets should be of the same type and alloys as the aluminum welding being repaired. Sealers should not be used until the directions are read and understood. Welding should be performed by personnel trained in aluminum welding. Care should be exercised when using heat on aluminum, as excess heat can decrease the strength of aluminum, lower the resistance to corrosion, and cause wrinkling and overlapping. AGO 5244A 184. Repair Procedures a. Repairing Hole in Hull. Very small holes can be repaired with epoxy sealer. Allow 24 hours to dry, and then file the patched area smooth to fair with the rest of the metal. The equipment needed for repairing larger holes in aluminum hulls is a peening hammer, the proper size rivets for the patch, a piece of aluminum sheeting of the same alloy as that being patched, and a dolly block. The procedure for such repairs is as follows: ( 1) Peen hole carefully and file smooth. (2) Clean surface with aluminum wool, wire brush, or fine sandpaper. (3) Shape patch for hole, allowing about one-third overlap around hole. ( 4) Hold patch in place and drill guide hole. (5) Mix sealer; either pliobond which has a rubber base or epoxy which has a plastic base. (6) Apply sealer to area around hole to be patched. (7) Place patch in position and insert a rivet in drilled guide hole. (8) Tighten guide rivet with a helper holding patch in place. (9) Drill hole opposite guide rivet and install rivet. (10) Continue around patch with riveting. Note. If the patch is on the side of the hull with little curve, the rivets can be placed any distance apart, but not exceeding 2 inches. On the deep curve of the hull or in the chine, transom, or a flat bottom, the rivets must be placed not more than % inch apart. b. Cropping, Bumping, and Fairing. Therepair procedure most often used is known as bumping or fairinp The extent of this type work will be determined by a qualified marine inspector. The bumping process shown in figure 155 can be used to repair parts slightly damaged. If there is a break in the plate, bump plate into shape, cut out a 60-to 90-degree V-angie, and weld. For seriously damaged parts, mark part for identification, remove, and repair in a repair shop as follows: ( 1) Straighten plate in mangle or, if necessary, roll to shape using a set of templates. (2) Shape twisted pieces by applying localized furnace heat, or restore to proper form by cold press. (3) Fair small plates or brackets on slabs with controlled heat. Note. Overheating will cause wrinkling and overlapping because of the elasticity of aluminum. Crop or cut away any overlap to obtain proper fit of plate. c. Repairing Cracks in Hull. There are two methods of repairing a crack in the hull: rivet a plate over the crack, or weld the crack closed. If the crack is in a plate ){6 to %6 inch thick, UNDER 1/16 INCH ~ [ p II [ p I~ [ p [ p ~ [ p ~I' 1/4 TO liNCH 1/16 TO 3/16 INCH Figure 163. Preparing aluminum for welding. it should be notched about every % inch with a chisel as shown in figure 163. Sheeting over 1;4 inch thick should be veed or beveled to about a 60-to 90-degree angle and notched before welding. To repair a crack by riveting a plate, refer to a above. Figure 164 shows different methods of placing rivets. d. Repairing Gouges and Scratches in Hull. Deep gouges can be worked out with a rubber mallet. Care must be taken, as there can be too much metal to fill the gouge area, in which case a blowtorch should be used to heat the metal and work it in shape with the mallet. Scratches should be cleaned and rough edges filed and filled with aluminum sealer. After drying for 24 hours, the sealer should be filed even with the hull. e. Repairing Dents, Buckles, and Wrinkles in Hull. Dents, buckles, and wrinkles can be straightened with a rubber or fiber hammer and a dolly block. For metal over 1,4 inch thick, apply heat. f. RepaiTing Frame. Before repairing a frame inside an aluminum hull, it is necessary AGO 5244A 0 0 0 0 0 SINGLE-RIVETED DOUBLE-RIVETED LAP LAP JOINT JOINT, STAGGERED TWO TYPES OF JOINTS 0 0 0 0 0 0 0 0 - SINGLE SPLICE PLATE DOUBLE SPLICE PLATE SINGLE-RIVETED BUTT JOINT 000 0 0 0 000 0 0 000 0 0 000 lo o o ,CHAIN-RIVETED, STAGGER-RIVETED,SINGLE SPLICE DOUBLE SPLICE DOUBLE-RIVETED BUTT JOINT Figure 164. Method8 of placing rivet8. to remove rivets. After rivets have been removed and it is determined that the frame is only bent, it can be brought back into position with hydraulic jacks, heat, and steady tapping with a rubber hammer. If the rivet holes do not line up, they should be filled with a sealer such as epoxy and new rivet holes drilled. If the frame is broken, the same procedure is used as with a bent frame, except that a plate should be fitted across the break and riveted in place. g. Repairing Chine and Clamps. When repairing the chine or clamps, a rubber hammer with a dolly block is required for dents in plates less than 1,4 inch thick. Use heat for dents in plates over 1,4 inch thick. Cracks can be welded or filled with sealer and a plate of equal strength and alloy riveted over the crack. Rivets should be no less than % inch apart. h. Installing Bottom Stiffeners. For a round bottom hull, stiffeners should be sh~ped with a template before installation and should be AGO 5244A riveted in place between the stringers. When necessary to repair gouges or cracks in the bottom of the aluminum hull, only one stiffener may have to be removed. 185. Use of Template and PaHerns in Making Hull Repair Templates and patterns are very important in aluminum hull repair, as the plates should be formed on a slab or mangle before being installed in the hull. This is especially true with sheeting over 1,4 inch thick. Plating under 14 inch thick can be formed by hand as it is installed. The making of templates is explained in detail in chapters 2, 4, and 13. 186. Repairing Hull by Welding There have ben two relatively new processes developed for welding aluminum. They are tungsten-arc inert gas (TIG) and shielded inert gas metal arc (SIGMA). The following inert gas welding machines are available through supply channels to maintenance activities responsible for this category of hull repair: Type__________________Tungsten inert gas Make__________________P&H Rating_________________300 amperes Model _________________ DAR 300 HFSG Specification No,________2100 H1580 FSN__________________ 3431-984-3401 and Type__________________ Metal inert gas Make__________________Linde Rating_________________300 amperes Model _________________ SWM7 SV1-300 FSN__________________ 3431-731-4163 Oxyacetylene and oxyhydrogen gas welding processes are also used for aluminum welding but are limited to materials ranging from 0.040 to 1 inch in thickness. Materials heavier than 1 inch are usually not welded with oxyacetylene or oxyhydrogen gas because the heat dissipates too rapidly and it is very difficult to melt the metal with a torch. Material thicker than 1 inch is normally metal arc welded. The major problem in obtaining a satisfactory joint with aluminum is the removal of the tenacious oxide film that forms on the surface of the material. It is this oxide film that gives aluminum its great resistance to corrosion; however, its presence also prevents satisfactory fusion of the metal. Flux residues also contain chlorides 203 and other salts which are corrosive to aluminum if left in contact with it. Therefore, it is essential to remove these residues with a brush and hot water. a. Procedures for Gas Welding. (1) Edge preparation. Thickness of the material determines the method of edge preparation. As a rule, the edges are prepared in the same manner as the edges of similar thicknesses of steel. There are, however, noteworthy differences. On thin material up to about ){ 6 inch thick, the edges should be formed to a 90-degree flange about the same height as the thickness of the material or higher. The flanges perform two important operations. They prevent excessive warping and buckling and serve as a filler metal when flanges are melted down in the welding operation. This makes the use of a filler rod unnecessary. The only requirement for the flanges is that the edges be straight and square. If desired, materials up to about % inch can be welded with a flange-type joint. Unbeveled butt welds can be made on thicknesses from 1i 6 to %r. inch, but in this application it is necessary to notch the edges with a saw or a cold chisel. Edge notching is recommended in aluminum welding because it serves to facilitate full weld penetration and to prevent local distortion. It also minimizes the likelihood of burning holes through the joint. All butt welds in material over 1Js inch thick are notched in the same manner. In gas welding thicknesses over ~~ r. inch, the edge is beveled to secure thorough penetration. The included angle of bevel can be from 90 to 120 degrees. Single V welds can be used on material up to about 11 7 inch. Notching is used to supplement the beveled edges. (2) Cleaning and preheating. After the edges of the pieces have ben properly prepared, the surfaces to be welded should be cleaned of grease, oil, and dirt. The presence of oil or grease, can necessitate the use of a deterent, soap and water, naphtha, or other nonflammable, nontoxic solvent to complete the cleaning job. Aluminum plates %, inch thick or over should be preheated to prevent cracks and assure more complete penetration. Preheating to a temperature of from 300°F. to 500°F. (149°C. to 260°C.) is sufficient. Thin materials can be preheated with a welding torch prior to welding. It is important that the preheating temperatures does not exceed 500°F. (260°C.), as the desirable properties of certain aluminum alloys can be destroyed at higher temperatures. If a pyrometer is not available, a mark made with a blue carpenter's pencil or heat crayon will turn white at the preheating temperature. Cold aluminum gives a metallic ring when struck. This sound becomes duller as the temperature rises and disappears entirely at the temperature required for welding. (3) Welding flame. Oxyhydrogen flame is recommended for welding aluminum up to % inch thick, -and oxyacetylene flame for aluminum 1ft inch thick and up. In welding aluminum, a neutral or slightly reduced flame gives the greatest speed and economy as well as a clean weld of good soundness. Should the flame become oxidized, it will cause the formation of aluminum oxide, resulting in poor penetration and a defective weld. ( 4) Weld'ing flux. The use of flux in welding aluminum is extremely important. Aluminum welding flux is designed to remove the aluminum oxide by chemically combining with it. In gas welding, the oxide forms rapidly in the molten weld pool. It must be removed or a defective weld will result. To insure the proper distribuUon of flux, it should be painted on the surface to be welded and also the welding rod. After welding is completed, all tr2ces of adhering flux should be removed. This can be accomplished by using AGO 5244A boiling water or steam jet or by immersion in cold water with 10 percent sulphuric acid for 30 minutes or in hot water with 5 percent sulphuric acid for 10 minutes. (5) Welding technique. After the material has been properly prepared and fluxed, the flame is passed in decreasing circles over the starting point until the flux melts. The rod should be scraped over the surface at about 3-to 4second intervals, permitting the rod to come clear of the flame each time. The scraping action will reveal when welding can be started without overheating the aluminum. The rod should remain under the flame long enough to melt the amount of metal needed. One of the difficulties in aluminum welding is failure of the deposited metal to adhere. This is generally caused by attempts to deposit the weld metal on cold base metal. After the flux melts, the base metal and the filler metal can be brought to the molten state simultaneously, forming a solid weld. b. Degree of Repair by Weld£ng. Aluminum welding is successful in butt welding material up to 5fa inch thick, provided that both plates are of the same thickness and have the same alloy content, and both butt ends are prepared properly. Each butt end must be shaped to form a 60-to 90-degree V and notched. Insure that the aluminum does not come in direct contact with steel, causing an electrolytic reaction and subsequent fatigue to the aluminum joint. The same precaution pertains to damp or wet wood which would cause electrolytic reaction and corrosion. 187. Repairing Hull Using Rivets and Bolts a. Types of Rivets and Riveting Procedure. The size of rivets required in hull repair is limited to about % inch. The development of larger rivets is complicated by problems of driving them. Cold driving must be done quickly; otherwise, the rivet hardens to the extent that it cannot be driven. Hot driving requires a careful control of temperature to prevent damaging the rivet. In driving rivets in aluminum, AGO 5244A two methods can be used, hand driving with a dolly block or pneumatic driving with a bucking bar. A few heavy blows are more effective than many light blows, particularly when hand riveting. It is desirable to close a rivet in 30 seconds to avoid too much cold working. In order to extend the diameter of rivets which can be driven, the nonheat-treatable rivets of some alloys can be driven hot. These materials cannot be heated indiscriminately as can be done with steel rivets. The practical temperature range is from 752°F. to 932°F. ( 400°C. to 500°C.). It is important to heat the rivets near the upper end of the temperature range. Allow them to soak at this temperature for about 15 minutes. Due to the high thermal conductivity of aluminum, rivets cool very rapidly once they are in contact with cold metal. For this reason, rivets should be installed as quickly as possible after heating. The holes in aluminum parts which are to be connected by rivets can be either drilled accurately to size or punched and reamed to size afterward. Drilling is preferred with aluminum, and care must be taken in centering the hole so that the use of drifts to bring holes into line is avoided. Hole clearance should not be too great, or the hole will not be completely filled when the rivet is driven. The best practice is to allow a clearance 1 of Kt to 1:! 2 inch maximum. Within these limits, the shear strength of the rivet is not affected either in hand driving or in pneumatic driving. b. Types of Bolts Used in Hull Repair. Stainless steel or galvanized bolts are used to attach aluminum superstructures to the main steel structure. Cadmium-plated steel bolts should not be used. The bol'ts should be dipped with zinc-chromate primer immediately before use and nonmetallic ferrules installed on the bolt shank. Insulating washers will be used, if possible. 188. Preservation and Finishing Aluminum Hull a. Aluminum must be primed before painting. Before priming new aluminum, the surface must be cleaned with naphtha solvent, and then washed down with clear water. New aluminum must be etched before primer or paint will adhere. Phosphoric acid is a good etching liquid. b. To remove old paint from aluminum, proceed as follows: (1) Swab all aluminum and aluminum alloy surfaces to be painted with a hot, 10-percent solution of chromic acid conforming to Military Specification 0-C-303. Immediately after the swabbing, rinse the surfaces thoroughly in clean, warm water, and dry. (2) Clean surface with wire brush or sanding block and very fine sandpaper. (3) Etch hull with phosphoric acid. (4) Apply two or three coats of zincchromate primer to surface. (5) Apply three coats of antifouling paint to hull from bottom up to boottop, and two coats of good marine paint from boottop to bullards. c. Small vessels that can be easily removed from the water need not be painted. To keep the hull surface clean and bright, go over the hull once or twice a year with aluminum wool. AGO 6244A CHAPTER 8 STEERING SYSTEMS 189. General A steering system supplies the medium for moving the rudder of a vessel to enable it to change course or direction. The steering system of any vessel must be rugged and designed so that the rudder cannot overpower or control the steering wheel of the vessel. The steering gear on any vessel must be so designed that a relatively small amount of force, applied to the driving wheel, will produce a large amount of rudder movement or torque. A steering system includes the steering wheel, transmitting assembly, and, on larger vessels, a driving engine. The most common types of steering systems in use today are the link-rod, chain-cable, steam, electro-mechanical, and electro-hydraulic systems. Emergency tillers are used to control small vessels when the steering system is inoperative due to damage or malfunction. Aboard U.S. Army vessels, the marine hull repairman is responsible for maintenance of rudders, which includes pressure testing and maintenance of rudder stock, rudder post, and pintles and gudgeons. When required by the marine engineer or machinist, the hull repairman performs repairs to various engine components. The maintenance and repair of starting engines, however, is performed only by the marine engineer or machinist. 190. Link-Rod Type Steering Gear a. Description. The link-rod type steering gear (fig. 165) is controlled by worm gears, located behind the steering wheel panel and joined to the steering wheel shaft. A vertical rod sleeve is connected to the worm shaft and to the short shaft extending upward from a horizontal brace attached to the bulkhead of the engine compartment. An arm joins the vertical rod to the horizontal rod which is connected to the rudders. The rudders are connected by a tie rod with clevis ends. An arm from the rudder post connects with the clevises. The rudders are held by a flange bolted to a support shelf. The flange is combined with a stuffing box. Normally, four turns of the wheel are required to turn the rudders from full port to full starboard. To locate the rudders amidships, turn the wheel hardover in one direction, and then make two turns back in the opposite direction. For easier operation, a small amount of play is left in the wheel adjustment; however, the wheel should take hold at not more than a one-quarter turn. b. Replacement of Steering System Bolts. The most frequent repair necessary on the linkrod type steering gear is replacement of bolts and/or clevis pins in the tie rod system. These items should be checked periodically for excessive wear and looseness. c. Adjustment and Packing of Stuffing Boxes. Adjustment of the stuffing boxes for watertightness is made by loosening the lock nuts, tightening the packing nuts, and then tightening the locknuts. The lock nuts will prevent the packing gland nuts from loosening. When it becomes necessary to use considerable pressure to tighten the locknuts, the stuffing boxes should be repacked with flax or original-type packing as supplied by the builder. Drydocking the vessel is mandatory when the packing gland has to be completely removed. Packing should be installed in a stuffing box in rings with ends cut square, not beveled. Sufficient clearance should be left between the ends of the rings to allow for elongation when the packing is set up. The cut rings should be installed in the box, one at a time and with joints staggered. The gland is inserted, each nut tightened with a wrench, and the nut is backed off until it is fingertight. The locknuts are then tightened against the packing gland nuts. A slight leak- AGO 6244A STEERING ROD ADJUSTMENT POINT VERTICAL STEERING ROD TIE ROD LINKAGE ADJUSTMENT POINT ~~~~~?~~~~ "HORIZONTAL STEERING ROD STEERING ROD ADJUSTMENT POINT BRACE TIE ROD LINKAGE ADJUSTMENT POINT WORM GEAR BOX WORM SHAFT BOLTED TO STEERING ROD STEERING ROD ADJUSTMENT POINT ARM Figure 165. Example of link-rod type steering gear. AGO li244A age can occur during the time the packing is adjusting itself to the rod and box. As the packing expands, further adjustment of the packing gland nut and locknut could be necessary, depending upon the ease with which the rod turns. Packing should never be jammed tight with a wrench, as this increases the friction on the rod and causes wear of both the packing and the rod. If proper attention is given during the wearing period, the life of the packing will be extended considerably. When manufactured, rod packing is supplied with a definite amount of lubricant, and no additional lubricant needs to be applied when rod packing is installed. When a stuffing box is disassembled, the box, gland, rod, and studs will be carefully inspected for conditions which will cause trouble; unsatisfactory conditions will be corrected before the box is repacked. Care in installing rod packing is as important as using the proper material for packing. Therefore, care must be exercised to detect and correct existing deficiencies before installing new packing. The best grade of packing cannot effectively seal a rod if the following conditions exist: (1) Rod is bent, scored, or rusty. (2) Gland is cocked. (3) Stuffing box is scored or nicked. ( 4) Gland is not in alinement with shaft. ( 5) All old, hard, dry packing has not been removed. (6) Threads on the gland studs are burred and prevent setting up of the gland nuts. Caution: Extreme care must be used when tightening packing gland nuts to avoid cocking or bending the packing gland. d. Alinement of Link-Rod Type Steering Gear. Alinement should be accomplished during any overhaul inspection while the vessel is out of the water, but it can be done at dockside by qualified personnel. Alinement of link-rod type steering gear is accomplished as follows: (1) Remove emergency tiller cover plate in aft cockpit and insert emergency tiller. (2) Set tiller in dead ahead position and check to insure both rudders are parallel. (3) Adjust tie rod linkage if necessary to line up rudders. ( 4) Check to determine that ·steering wheel is approximately in center of its movement when emergency tiller is dead ahead. ( 5) Center steering wheel position by adjusting horizontal steering rod assembly. 191. Chain-Cable Type Steering Gear a. Description. The chain-cable type steering gear (fig. 166) consists of a sprocket wheel on the steering wheel shaft with a roller chain fitted over the teeth. Connected to each end of the chain is a wire cable which runs through pulleys to the rudder quadrants. The cable ends are connected to the chain and quadrant by clamps or by open and close sockets. Turnbuckles are located in he cable near the chain to permit adjustment of the cable. b. Replacement of SpTocket Wheel Setscrew. The setscrew which holds the sprocket wheel key in place on the chain-cable type steering gear can become loosened by vibration, permitting the key to fall out. The setscrew should be examined from time to time, and if frequent adjusting is required, one of the following changes may be necessary: (1) Use a longer setscrew with a locknut. (2) Replace original setscrew with squarehead setscrew which has been drilled to permit safety wiring. (3) Drill, ream, and install a taper pin through gear hub and shaft. Care must be taken to determine the proper size taper pin hole to prevent weakening the shaft excessively. c. Tightening Wire Cables. When the steering begins to exhibit looseness, the wire cables can need tightening. On some cable-chain type installations, the cable is tightened by adjusting the clamps or turnbuckles which fasten the cables to the chain. On installations using open and close sockets as cable end connectors, the open sockets will have to be resocketed at the quadrant when the turnbuckles reach maximum AGO 6244A 209 SPROCKET WHEEL / CHAIN --------------~ ~-=-=-=-----------------...... ~r r ~> ~----~ ------- PACKING NUT RUDDER STUFFING BOXQUADRANTS DOUBLE SHEAVE PULLEY Figure 166. Chain-cable type steering gear. adjustment. The open sockets should be red. AUnement Of Chain-cable Type Steering Gear. Alinement of a cable-type steering gearsocketed far enough along the cables to take requires that the rudders be parallel and theup the slack with the turnbuckles about threesteering wheel be in the center of its range ofquarters open. Both cables mus,t be shortened movement when the rudders are positionedthe same amount, so that the steering system dead ahead. Alinement procedures are as folremains approximately centered. On systems lows: using a single cable mechanism, the adjust(1) Remove chain from sprocket wheel of ment is made at one cable end connection. steering wheel shaft. AGO 6244A 210 (2) Position rudders, using emergency tiller, to dead ahead position. (3) Adjust rudder quadrant tie rod as necessary if rudders are not parallel. (4) Reinstall chain on steering wheel sprocket with rudders centered dead ahead. (5) Adjust length of main cable by resocketing if ends of chain are not even with each other. 192. Steam Steering Gear a. A steam steering gear consists of a reversible, reciprocating steam engine working through reduction gears to drive a geared quadrant attached to the rudder stock. Reversing and speed control of the engine are accomplished by use of a differential valve which reverses the steam connections to the slide valve chamber. Control of the differential valve is accomplished through a mechanical differential actuated by a trick wheel in the steering engine room or by some other distant control device. The differential provides a followup capability which allows the rudder to lag behind the wheel by the full angle of rudder movement. Motion of the rudder is transferred back to the differential by the followup gearing so that when the assigned rudder angle is reached, the differential closes the differential steam valve and the steering engine stops. b. The valves in the engine room controlling the supply and return of steam to and from the steering engine should be locked wide open while the steering gear is in operation. When starting a cold engine, the steam is admitted slowly and the engine rocked or turned slowly until all water has been cleared from the cylinders and the engine has been brought to operating temperature. c. Maintenance. (1) Inspection. The steering gear should be inspected carefully at frequent intervals. Any steam or oil leaks, worn pins or bushings or gears, or any other suspected cause of trouble should be reported immediately and repairs made at the first opportunity. AGO 5244A (2) Steam valves. Steam valves removed from their cylinders must always be reinstalled in the same cylinder. These valves are generally fitted individually. A valve replaced in another cylinder can operate satisfactorily when cold, but can seize when brought to operating temp~rature. (3) Preservation. Active vessels not underway should have the steering gear turned over at least twice each week for proper preservation of pistons, valve stems, and other parts. (4) Draining steam system. Drain valves should be left open on all idle steering engines so that any steam or water which has entered the engine through a leaking inlet valve can drain out. This is especially important in cold weather when the water can freeze and break the engine cylinders or jackets. Drain valves should be inspected frequently to insure that drain holes are not clogged. During very cold weather, the steering engines should be warmed up at frequent intervals. This reduces the danger of cracking the cylinder due to excessive internal stresses which build up when steam is turned into very cold cylinders. (5) Starting a cold engine. When starting a cold steering engine, the following actions will be taken: (a) Insure cylinder drains are open. (b) Open exhaust valves. (c) Rid lines and cylinders of condensation by cracking steam stop valve off its seat. (d) Open steam stop valve slowly. (e) Turn engine over slowly to warm up and eliminate condensation. (f) Close cylinder drains. 193. Electro-Mechanical Steering Gear a. General. The electro-mechanical steering gear (fig. 167) employs an electric steering unit which can be directly connected to the rudder stock or indirectly connected to the rudder stock by a tiller or quadrant with wire AUTOMATIC FOLLOWUP -- RUDDER STOCK MOTOR RUDDER QUADRANT STEERING SHEAVE CABLE STAND Figure 167. Example of an electro-mechanical stee1·ing gear. rope transmission. The most common type of direct-drive electric steering mechanism is the electric screw type in which the screw is driven by either of the two motors through magnetic clutches. The mechanical components of this steering arrangement are generally the same as those of the screw-type hand steering equipment. The electric quadrant-type steerer is also a direct-drive gear, in which a quadrant on the rudder stock is driven through gearing by an electric motor. The steering wheel is often mounted directly at the steering unit, although remote control is applied in some cases. b. Steering Control. Electro-mechanical steering motor control can be either the nonfollowup or follow-up type. In the nonfollowup type, the motor is controlled by a master controller at the steering station. The controller will generally have three positions: port, off, and starboard. The followup type control generally employs a roller and ring-type contact in the steering stand. The rollers are geared to the helm so that rotation of the wheel brings a roller in contact with a contact ring. The ring is connected to contactors in the motor control panel so that the motor starts turning in the required direction when a circuit is closed. The rotation of the motor, which is geared to the rudder, is transmi,tted by mechanical or electrical linkage to the contactor ring in the steering stand. When the ring has rotated to the position called for by the helm, the electrical circuit is broken and the motor stops. Most wire rope and chain drive steering gears use a followup control system. In some instances, the shaft which provides followup control can also be used as a means of emergency steering by connecting the shaft to the helm mechanically. This system is generally employed only on small vessels where rudder torques are relatively small. c. General Maintenance. ( 1) Steering gear motors should be maintained in accordance with instructions for care of electric motors, as given in applicable component technical manuals. Gears, clutches, brakes, and other mechanical parts should be frequently inspected and lubricated. (2) Where visible, steering cables should be inspected frequently when the vessel is underway. The cables are also inspected and tested at the annual shipyard overhaul. If found to be in good condition at this inspection, the AGO 5244A cables should be properly lubricated and reinstalled. If there is evidence of excessive wear or breaking of wires in a strand, the defective steering cable should be replaced with prestretched cable. Care should be exercised to have the proper tension on the new cable to prevent rudder play and cable strain coming off the quadrant or drum. All components of the steering system should be examined during the inspection. (3) Rudder actuating chain and wildcats should be inspected at least once each 6 months and, if in good condition, should be well lubricated and tightened to eliminate slack. 194. Electro-Hydraulic Steering Gear a. General. The electro-hydraulic steering system controls the rudder with hydraulic rams operating in cylinders connected to variable delivery hydraulic pumps. The pumps are driven by continuously running electric motors. The direction and rate of rudder travel are controlled by changing the position of the tilting block in the hydraulic pumps. On large vessels, two complete power units are provided for each ram group as a safety measure. In all such dual installations, both motors and pumps can operate at the. same time; however, in most cases only one pump at a time can be connected to the hydraulic ram. b. Transfer Valves. A six-way transfer valve is provided in the hydraulic lines betwen the pumps and the ram cylinders. The purpose of this transfer valve is to connect either of the two pump units to the ram cylinders. In some installations, the transfer valve can be made up of two separate four-way valves connected by piping to serve the same function as a sixway valve. The transfer valve is multiported and, in most cases, has three positions: port, lock, and starboard. The lock position establishes a hydraulic lock on the rudder by closing the lines leading from the ram cylinders. In this position, lines from both pumps are ported to make a closed loop with the pump, and the fluid circulates through this loop when the pump is running. When the transfer valve is set to connect one pump to the ram cylinders, the AGO 5244A other pump is still connected :to bypass the fluid the same as when the valve is in the lock position. On most vessels, the transfer valve is manually operated and held in one of the three positions by detents. On the vessels, the transfer valve is operated by hydraulic pressure from the control servo systems. In these systems, the transfer valves are springloaded to return to the lock position each time servo pressure is lost due to a power failure or pump stoppage. In some servo-operated transfer valves, the operation is controlled by a small manually operated valve which also has the three positions: port, lock, and starboard. On other servo-operated systems, the valve to the first pump unit energized will open automatically. c. Nonoverhauling Devices. If a hydraulic pump is left connected to the ram group when the pump motor is deenergized, it is possible that forces acting on the rudder will build up sufficient pressure in the hydraulic system to make the pump rotate, provided the tilting block within the pump is at some degree of stroke. To prevent this motoring of the pump unit and rudder movement, a nonoverhauling device is installed on the steering gear. In the case of servo-operated transfer valves, a nonoverhauling device is not required, as the ram group is hydraulically locked when the pump is stopped. Steering gears having manually operated transfer valves have either a friction brake on the drive motor, which sets automatically when the motor is stopped, or a mechanical backstop, which prevents overhauling. Manually operated transfer valves should always be set on the lock position when both pump units are secured. d. Relief Valves. Relief valves are provided in all hydraulic steering systems to protect the components from damage due to excessive pressures. These valves are set at 10 percent, plus 50 psi, in excess of the maximum normal operating pressure. Relief valves should be tested and set during regularly scheduled overhauls. e. Replenishing Valves. Replenishing valves are provided in hydraulic steering systems for automatic makeup of any fluid which can be lost by leakage. A low pressure supply of hy draulic fluid passes through the check valve to both lines leading to the ram cylinder. If leakage has depleted the fluid being pumped from one ram cylinder to the other, replenishing fluid is taken in through the check valve on the low pressure side to keep the system filled. Cocks are provided in the hydraulic system for purging the system of air or for vent ing when draining the system. f. Horsepower Limiter. In order to reduce the size of the motor which would be required on the steering gear for some vessels, a pressure-operated stroke control mechanism or horsepower limiter, also cailed a torque equali:;~er, is installed in the hydraulic system. The horsepower limiter usually consists of a springloaded piston in a hydraulic cylinder. The cylinder is automatically connected to the high pressure side of the ram system through a shuttle valve. When oil pressure builds up in the system due to high rudder pressure, the oil pressure eventually overcomes the force of the horsepower limiter spring and the piston begins to move. The piston reduces the pump stroke by an ELECTRIC MOTOR Figure 168. Typical single rudder, single ram, rapson slide. AGO 6244A amount proportional to the load, through a linkage which overrides the steering control mechanism and thereby reduces the power re quir3d to turn the pump. This action permits a reasonably small motor to pump a large volume of fluid at low pressure for fast rudder rates, and still provide the high pressure, at a re duced rate, which is required for high rudder torque. g. Rudder Linkages. Various methods are used for connecting hydraulic rams to the rudder stock. The exact configuration of steer~ ing gear and the method of transmitting the force of the ram to the rudder depend upon available space and special requirements. Although other arrangements have been used, the most common are described below: (1) Single rudder, single ram, rapson slide. This type rudder linkage (fig. 168) consists of a port and starboard cylinder operating a single ram having a crosshead block mounted in the center. As the ram moves in and out of the cylinder, the crosshead imparts a turning movement to the yoke which is mounted on the rudder stock. (2) Twin rudder, single ram, link type. Vessels having twin rudders have a single ram, generally set athwartships between the rudder stocks. Links connect the ram crosshead to the tillers on the rudder stocks. (3) Single rudder, twin ram, rapson side. Recent steering gear designs for large, single rudder vessels have two rams set fore and aft, one on each side of the rudder stock. These rams operate the rudder through a double yoke tiller with sliding blocks. ( 4) Single rudder, twin ram, link type. On vessels having limited space around the rudder stock, the fore-and-aft twin rams can be located forward of the rudder stock and the ram crossheads connected by links to twin tillers on the rudder stock. h. Indicating Equipment. Rudder and helm indicators (fig. 169) are provided in the steering gear room. The differential input shafting is driven by the control mechanism and indicates AGO 62«A the rudder angle called for by the helmsman. The rudder angle indicator is linked to the rudder stock through the follow-up shaft and indicates the actual rudder position. Remote reading indicators are also provided at distant steering stations. i. Emergency Steering Gear. Emergency steering gear is provided on all vessels having electro-hydraulic steering gear. Large vessels usually possess an auxiliary electro-hydraulic system as an emergency steering gear. Smaller vessels use hand-operated hydraulic pumps supplemented by chain falls or jacking nuts. (1) Electro-hydraulic emergency steering gear. Many large vessels have a separate hydraulic power unit for each steering gear. This power unit is located in the opposite steering gear compartment or in a separate compartment above the waterline. These units consist of electric motors driving variable delivery hydraulic pumps which are connected to two cylinders of the ram group. These systems can operate with the ram cylinders and main steering gear submerged. All connections and valve operations are automatic. A handwheel is used to con- RUDDER ANGLE INDICATOR FOLLOWUP SHAFT Figure 169. Indicating equipment. trol the flow of fluid to the rams and operate the rudder at a greatly re duced rate. (2) Hand-driven emergency steering gear. Hand-driven emergency steering gear consists of a _ hydraulic gear pump, capable of operating in either direction of rotation, and associated shuttle valves, piping, relief valves, and fittings. The pipes from the hand pump are connected to the ram drain lines to eliminate the need for additional high pressure cutoff valves. Some vessels have an emergency hand steering system in which the electric motor can be disengaged from one of the main pumps and the pump then operated by hand. The emergency steering systems for the electrohydraulic steering system require an intact hydraulic system for operation; therefore, rudder positioning equipment is also furnished in the event the hydraulic system becomes inoperable. This equipment generally consists of jacking nuts, drum, and cables or, in some older installations, chain hoists. Rudder positioning equipment should be employed only when the vessel is dead in the water. j. Hydraulic Pump Servo Systems. The force required to operate the tilting block in large variable delivery hydraulic pumps is considerably greater than that by which the relatively low torque control systems can operate. To make the tilting block operable by the control mechanism, a hydraulic servo is provided on the pump. The .servo is essentially a control valve which regulates a flow of fluid from a servo pump to a pair of servo pistons which move the tilting block. The servo pump can be driven separately by an electric motor; however, in most installations, the servo pump is driven from the main pump shaft. The servo system has a built-in followup which stops the tilting block at a point determined by the con trol mechanism. k. Mechanical Control Differentials. Mechanical control differentials control rudder angle by transmitting rudder angle orders from the distant control mechanism to the hydraulic ram. Failure of a differential mechanism results in loss of steering control by the power unit controlled by that particular differential. On installations where a single differential controls both power units of a dual system, all power steering control will be lost if the differential fails. Repair of mechanical control differentials should be accomplished in accordance with applicable technical manuals. l. Adjustable Control Stops. Adjustable control stops are provided in the control system to limit the movement of the differential input shaft to the equivalent of hardover-to-hardover rudder movement. It is important that these stops be correctly adjusted to prevent damage to the differential gears and follower mechanism in case the follower reaches the end of the groove in the cam face. To further safeguard the steering gear against damage, the rams are arranged to come into contact with renewable copper crushing pieces before the rudder reaches the extreme limits of its travel. m. Maintenance Procedures. (1) Cleanliness of hydraulic systems. The importance of cleanliness in hydraulic systems cannot be overemphasized. Dirt or foreign matter in steering systems can destroy hydraulic pumps, cause valves to stick, score cylinders, ruin packings, and disrupt control systems quickly and with possible disastrous results. Systems should never be opened except for good cause and then only by experienced, qualified personnel. Care should be exercised to kep out dirt while systems are open, and all parts should be carefully cleaned before being reinstalled. Any filters installed in the active hydraulic system should be changed or cleaned regularly. All fluid in the active system should be pumped through the installed external filter at least once each 6 months, and any fluid added for replenishment of the system should be carefully filtered. Only approved----gasket materials or packings should be used when replacing such items in the steering systems. Any piping or tubing which is detached from the system during repairs should be plugged AGO 6244A and protected from damage while removed. Only clean hydraulic fluid of the type specified in the applicable technical manual for the system should be used for refilling or replenishment. Caution: Extreme care should be exercised to keep any water from entering a hydraulic system. (2) Ram packings. The packing used in the ram cylinders is designed so that the edges are expanded against the ram by the pressure of the fluid in the cylinder. It is important that the applicable technical manual be referenced for determining the packingtype specifications and installation procedures. The packing glands should be sufficiently tightened to allow a film of oil to remain on the rams as they extend from the cylinders. An occasional drop of oil leaking past the packing is not considered objectionable. Packing glands which are drawn up too tightly create friction, causing premature wear of the packing and rams. (3) Control differential maintenance. Differential mechanisms should be adequately but not overly lubricated with a clean, specified lubricant. Repairs and internal inspections should be performed only by competent, authorized personnel. Inspection of the differential should be accomplished at each scheduled overhaul. The differ€ntial and the mechanism in the differential control case should be flushed with an approved cleaning fluid, inspected for damaged or worn parts, and adequately lubricated. If parts are removed or disconnected, care must be exercised to realine all shafts, gears, and· couplings in their correct positions before reinstalling. 195. Emergency Tiller One type of emergency tiller (fig. 170) consists of a rod or tube which is bent at an angle and; designed to fit over or into the rudder stock or quadrant. The emergency tiller is inserted through an emergency steering hole in AGO 6244A the aft section of the deck. The hole is cov~red by a plate which can be removed by the use of a special key. The emergency tiller can be operated by one person. This tiller operates in the same manner as a regular tiller in that a turn to port is accomplished by moving the handle toward the starboard side. On larger vessels, emergency steering is accomplished by connecting blocks and tackle to the quadrant and to a capstan. The capstan is used to supply the power to move the rudders. 196. Distant Control System Because of the distance between the bridge and steering gear compartment, large vessels use a hydraulic telemotor or an electric system for steering gear control. The telemotor system can be of either the plunger or rotary pump type. The plunger type consists of a pair of transmitting plungers in the pilothouse connected by hydraulic tubing to a pair of receiving plungers at the steerer. It is necessary to provide a means for equalizing the system at zero rudder angle because 'of leakage. This can be done either by a cam-operated or electrically- Figure 170. Example of an emergency tiller. operated equalizing valve or by providing equalizing or bypass ports for the transmitter plungers. When used in conjunction with an automatic steering system, the plunger-type telemotor should be returned to zero rudder angle before transferring control from automatic steering to telemotor. a. General. Several electrical steering gear control systems have been developed including the synchronous type, the step-by-step system, and the balanced-bridge or gyropilot type. The balanced-bridge or gyropilot type is most frequently used for harbor craft. In the balancedbridge system, the steering wheel moves a potentiometer to unbalance the circuit and, start the motor. The movement of the motor actuates a follow-up potentiometer to rebalance the ci'rcuit and stop the motor when rudder and helm are in approximate coincidence. The gyropilot system is a complete servo mechanism in which motion of the steering wheel regulates a power unit in the steering gear compartment. The effort on the wheel is independent of the force required to operate this control. In addition to hand steering, this system provides for automatic steering on a preselected course by taking its input signal from the gyrocompass system. b. Synchronous Transmission. (1) Power type. The power-type synchronous control system consists of interchangeable receiving and transmitting units which are wound-rotor induction motors with interconnected three-phase rotor windings. The transmitters are mechanically connected by gears to the steering wheels. The transmitter at each distant control station is electrically connected to a receiver in the steering room. The receivers control the operation of the rudder positioning mechanism in the stern of the vessel. (2) Synchro type. The synchro-type control is similar to the power-type control system except that the transmitter and receiver units are much smaller. c. Hand Electric Servo System. This system is an electric, closed loop servo consisting of a synchro or potentiometer geared to the steer ing wheel and connected through cables to a synchro or potentiometer in the steering engine room. The output from the amplifier controls a servo motor which in turn operates the hydraulic pump servo valve. d. Maintenance Procedures. (1) Vessels that have been in service for an extended period of time can have a variation reading in degrees between the actual rudder angle and the rudder angle indicator. This variation does not warrant overhaul of the control sys.tem if the variation is no more than 1 or 2 degrees. The error can usually be corrected by taking up lost motion in the linkages and gear trains. When making repairs and/or adjustments to the indicating equipment, the graduations on the ram stock or rudder should be used as a reference. (2) Excessive steering wheel effort in synchronous transmission control systems can be due to insufficient lubrication of gears and bearings, insufficient lubrication in the mechanical differential, or misalinement of control linkages and couplings. All mechanical, hydraulic, and electrical components of a steering system will have a routine check before and during operation. In addition, the complete system will be inspected and tested during each annual shipyard overhaul period. 197. Typical Hydraulic Systems a. General. A telemotor is a hydraulic device which controls the steering gear of a vessel from the pilothouse or control station. On some amphibious craft, a telemotor system consists of one transmitter or more at a steering station connected by piping to a receiver or receivers. Each transmitter and receiver are arranged so that movement of the steering wheel forces hydraulic fluid through the piping system, causing movement of the plungers in the receiver unit. The receiver plungers are connected to the pump control or valve operation mechanism of the steering engine. Telemotor 218 AGO 6244A transmitters consist of plunger and rotary pump types. b. LARC-V Hydraulic System. This hydraulic system is an open center system. There is no pressure buildup until a requirement is placed on the system, except that pressure caused by fluid friction in the valves and line. When no component is operating, pressures in the system will range from 25 to 250 psi, depending upon where in the system the pressure is checked. Maximum pressure in the system is controlled by relief or bypass valves. The maximum still pressure is 1500 psi. Fluid flows from the reservoir to the pump to a relief valve set at 1500 psi and from the relief valve to the flow divider valve in the steering system. The first 10 gallons of hydraulic fluid are diverted to the steer valve and cylinder and from the flow divider. The cylinder has an open center four-way valve constructed in one end which ports the fluid into either side of the piston as directed by the steering cylinder to the return line, and then ports the fluid back to the reservoir. If the pump fails, an internal check valve in the steer cylinder will allow the fluid to bypass, permitting emergency manual steering. c. LARC-XV Hydraulic System. The LARCXV is equipped with two complete, independent hydraulic systems. One system, called the main hydraulic system, operates the power steering, bilge pumps, ramp installation, and winch. The other system operates the service brake on the vehicle. The main hydraulic system is a closed center system, demanding type with hydraulic fluid circulating freely until required for power. Two variable-displacement type pumps provide fluid circulation and working pressures for the entire system. Four hydraulic fluid filters are mounted port and starboard of the converter and of the forward, neutral, and reverse transmission. A 25-gallon capacity hydraulic fluid reservoir is located on the starboard side of the converter and the forward, neutral, and reverse transmission. Warning: When handling hydraulic fluid, extreme care must be taken to prevent the fluid from making contact with an open wound or cut or from getting into the eyes of personnel. If this should happen, the affected area should be thoroughly washed with fresh water while medical assistance is being summoned. ,, d. BARC-LX Steering System. The BARCLX, when water based, is steered by two rudders located aft of the propellers. The starboard rudder is equipped with a quadrant and the port rudder with a tiller arm. The quadrant and tiller arm are linked together with a cross rod assembly for simultaneous operation of the rudder. The rudders are steered with the forward wheels by wire rope connected between the quadrant and starboard wheel column steering lever. Sheaves are provided at the various bends and turns of the wire rope to insure smooth operation. The following inspection should be a accomplished before BARCLX is put into the water: ( 1) Inspect tiller arm and quadrant for broken and malformed condition. If damaged, replace tiller arm and quadrant. (2) Inspect cross rod and clevis for broken and bent condition. If damaged, replace and adjust cross rod assembly. (3) Inspect rudder for cracked, chipped, or warped condition. Notify support maintenance unit if rudders are damaged. ( 4) Clean rudder bushing and sheave lubrication fittings and lubricate. If lubrication fittings are broken or clogged, replace them. ( 5) Inspect wire rope for broken strands and fraying at tie points and sheaves. Replace portion of wire rope that has broken or has frayed strands. (6) Inspect turnbuckles for breakage, and replace any that are broken. (7) Inspect sleeves and sockets for breakage. Replace sleeves and sockets if broken. ( 8) Inspect pulleys for craeks and breakage. If cracked or broken, replace. (9) Insure that capscrews attaching key plates are tightened securely. ( 10) Clean sheave pin lubrication fittings and lubricate. If lubrication fittings are broken or clogged, replace. AGO 5244A 219 e. Plunger-Type Telemotor Transmitter. This transmitter employs two plungers which are driven by a pinion and rack from the steering wheel. The steering wheel must be brought to the amidship position to replenish the fluid in the plungers. With this type transmitter, centering springs must be overcome each time a movement away from the amidship position is required. f. Rotary-Pump Telemotor Transmitter. The rotary-pump telemotor transmitter employs a reversible, parallel-piston, rotary pump to deliver fluid to the receiver. In this system, regardless of leakage, the transmitter can continue to be turned until the receiver reaches the end of its s,troke. At the end of the stroke, the oil pressure builds up until a relief valve opens and the oil is discharged to a built-in supply tank. Replenishing oil is automatically drawn from this supply tank, as required, to make up for leakage. Because centering springs are not installed on the receiver uni,ts of this system, no force is required to hold a given rudder angle. Synchro indicators are used to relay to the helmsman the angle called for at the telemotor receiver. The synchro indicator transmitter is gear-driven from the telemotor receiver plunger, and the synchro indicator receiver is mounted in the steering console. g. Filling Telemotor Systems. Specific filling and purging instructions for the telemotor system should be obtained from the applicable technical manuals for the vessel concerned. The replenishing tank for telemotor systems should be kept at least three-quarters full of fluid at all times using hydraulic fluid, Military Specification MIL-H-6083. Care should be exercised to keep all water or condensation from contaminating the fluid. h. Maintenance Procedures. In addition to insuring that clean fluid is used in the system, it is extremely important that all parts be kept clean when the system is opened for repair or inspection. Normally, there is little wear of internal parts in a telemotor system. Packings should only be drawn up tightly enough to prevent leakage. Excessive steering wheel effom can be caused by the following: (1) Lack of lubrication of the transmitter gears and bearings. (2) Binding of linkages on the steering engine. ( 3) Restriction in the hydraulic lines. (4) Packings drawn up too tightly. (5) Improper fluid in the system. 198. Rudders a. General. The simplest type of rudder (fig. 171) is a single, wide, flat plate fastened to a vertical shaft by arms set on alternate sides of the plate. The arms are steel forgings or castings, the forward edges of which can be gudgeons. Rudders for small craft are usually cast in one piece or cut from sheet metal, while rudders for larger vessels are constructed in single plate or double plate configurations. Large double-plate rudders are made into streamlined hydrofoils to reduce drag. These resemble wings of aircraft in cross section. In all cases, the rudder acts as a ~teering device by deflecting the flow of water. b. Types of Rudders. Rudders vary widely in area, shape, and type of balancing (fig. 172). Vessels requiring more than average maneu- Figure 171. Typical rudder. AGO 6244A verability have comparatively large rudders. Basically, all rudders can be classified as balanced, semibalanced, and unbalanced. The term balance refers to the relative proportion of rudder area which is fore and aft of the rudder post. The unbalanced rudder is entirely aft of the rudder post, and all the force necessary to deflect it must be provided by the steering system. A fully balanced rudder has approximately one half its area forward of the rudder post and needs far less force to be deflected and held, as the water flow is acting on both sides of the rudder. c. Repair or Replacement of a Rudder. On small vessels, rudder assembly repair is accomplished by lowering and removing the rudder and rudder stock. The weight of the rudder is carried either at the top of the rudder stock by a flange or carrier bearing unit or at the stuffing box unit directly above the rudder. To remove the assembly, the rudder must, if necessary, first be supported by blocking. The tie rods are disconnected from the tiller or quadrants along with the steering rods. The tiller or quadrant is then loosened on the rudder stock and the stuffing box gland removed. If the weight of the rudder is supported at-the top of the assembly, the hanger nut and lock nut are removed. The rudder must first be lifted slightly, then lowered until there is suf ficient room to remove the tiller quadrant, stuffing box nut, and packing box gland from the rudder stock. The rudder is then further lowered until the stock or post clears the rudder port. Repairs to the rudder are accomplished through application of standard metalworking practices. Reassembly of the rudder is essentially the reverse of the disassembly procedure. The single plate rudder is the most common type used today on small sea craft. This type of rudder is round or rectangular UNBALANCED SEMIBALANCED BALANCED Figure 172. Types of rudders. and is provided with gudgeons through which pintles are fitted. The pintles provide the pivoting from the stern post. A number of stays are placed opposite each gudgeon to stiffen the main rudder surface. In some cases, extra stiffeners are placed between each gudgeon, as shown in figure 173. The stays are either single or double riveted in place. To secure a correct position, a key is inserted in front of the rudder to prevent distortion of the rudder. If the stays are properly shrunk on the rudder, the key will show very little strain, indicating the rudder is properly balanced in place. To reduce friction and provide a means of effective repairs, the pintles are fitted with a bushing of lignum vitae. These bushings can be removed during repairs and rebushed. Bronze or white metal is sometimes used to prevent corrosion of pintles. The entire rudder assembly can be removed by removing the nuts from the pintles and quadrant and lifting the assembly up and out. During haul out, the drain plugs should be removed from the bottom of the rudder. These are usually the screwed-in type plugs fitting flush with the rudder surface. During repair of hollow rudders, the inside must be painted with a rust preventive paint such as zinc-chromate. Several heavy coats are recommended. Rudders can be reassembled while paint is still wet. After the paint has been allowed to dry, the hollow rudder should be air tested before reinstallation to insure watertightness. To air test a hollow rudder, compressed air is applied internally at 3 to 5 psi. Using liquid soap or a premixed soap solution and a paint brush, the entire surface of the rudder is brushed. If defects are present, small bubbles will appear and indicate the location. All defects requiring repair are to be marked. Warning: Do not apply air pressure in ex~ess of 5 pounds psi. Excess air pressure will cause the rudder to explode. d. Quadrant Repair. (1) Quadrant failure can consist of structural failure of the quadrant itself or be caused by damage due to excessive cable wear. Structural failure requires a survey to determine if the repair is practical or possible. Cracking or bending of the quadrant is re- AGO 5244A 221 ~ SECTION B-B SECTION A-A SEE DETAIL A MAIN PIECE BRACE MAIN PIECE STERN POST BRONZE OR WHITE METAL DETAIL A Figure 173. Typical gudgeon and pintles on single plate rudder. paired by welding or heat treatment. tached to the quadrants and ride in Many quadrants on small craft are the quadrant grooves. The cause is produced from a manganese-bronze usually due to improper alinement or alloy which requires special metaladjustment of cables. Repair is acworking techniques. Consult applicomplished by removing worn cabling cable welding and metalworking techand thoroughly cleaning the grooves. nical manuals for details of structural Care must be taken to see that the repair. new cable is properly lubricated and (2) Quadrants can be damaged by excesenters the groove without rubbing sive wear of the cables which are at-against metal edges. AGO 5244A CHAPTER 9 PROPELLERS AND SHAFTS Section I. 199. Propellers-General There are three types of propellers: in relation to construction, the solid and built-up propellers, and in relaion to function, the controllable pitch propeller. a. Solid Propellers. The blades and hub of a solid propeller are formed from a single integral casting and can have either constant or variable pitch. A propeller with a constant pitch will have the same pitch at each radius; a propeller with a variable pitch will vary, at each radius, from the nominal pitch and produce a particular distribution of loading over the propeller radius. The nominal pitch, in reference to the variable pitch propeller, usually corresponds to the pitch at the 0.7 radius. b. Built-Up Propellers. The blades and hub of a built-up propeller are cast separately and can be of different material. The blades are fastened to the hub by means of studs and nuts, and proper orientation must be secured to produce the designed propeller pitch. c. Controllable Pitch Propellers. Controllable pitch propellers are provided with actuating mechanisms which can change the pitch. Operating and maintenance instruction manuals should be consulted before overhaul or repairs are made on these propellers. 200. Propeller Vibration When vibration difficulties are encountered, the frequency of vibration should be the first thing determined. A vibration with a frequency equal to the revolutions per minute of the shaft is usually evidence of variations in propeller dimensions; excessive runout of the shaft taper, imbalance of the propeller and cap, or a combination of these discrepancies. The propeller PROPELLERS should be checked for proper dimensions, the propeller blade pitch and contour should be corrected, and the propeller and cap balanced. A vibration with a frequency equal to the product of the number of blades times the shaft revolutions per minute is called blade frequency vibration. This type of vibration is caused by hydrodynamic forces acting upon the propellers and the surrounding hull. Since blade frequency vibration is a function of the flow around the hull and appendages, the propeller is not necessarily defective. Blade frequency vibration can indicate a need for refinement of hull lines, a change in the number of propeller blades, or other design modifications. 201. Cavitation and Noise a. The flow of water around the propeller blades causes a reduction in pressure on some points of the blades. When absolute pressure is reduced on any blade surface below the vapor pressure of the fluid, vapor pockets or cavities are formed which break the continuity of flow and reduce the efficiency of the propeller. This is called cavitation. This phenomenon can also be caused from the irregular flow of water around damaged blade edges, and if cavitation bubbles collapse on the blade surfaces, erosion will result. b. Noise heard as a swishing sound is known as a cavitation noise. If this noise is well developed, .it will be violent and plainly audible in the stern area. Another type of noise emitted from propellers is called singing. This noise is characterized by a musical note which has a constant frequency over a range of propeller speeds. Singing can be caused by the propeller blades or by vibrations generated in the machinery system and transmitted through thE'\ AGO 5244A propeller. Singing can usually be eliminated by modifying the trailing edges of the propeller blades. 202. Cleaning Propellers a. The efficiency of a propeller is reduced by fouling. To prevent fouling, propellers should be cleaned when the vessel is drydocked. Barnacles can be removed by scraping or wire brushing and should be accomplished before the growth has dried out. The removal of appreciable amounts of metal by grinding or other methods must be avoided. b. After cleaning bronze propellers, polish with a fine abrasive and, if the vessel is to go into immediate service, no further cleaning needs to be performed. If the vessel is to be inactive for an appreciable period of time, the propellers should be coated with a corrosion preventive compound. In case the vessel is laid up but will be docked again prior to being placed in service, the propellers should be painted with the same paint and quantity of coats as the hull of the vessel. Hone blasting to clean propellers must be controlled so that blade surface roughness or other side effects will not be produced. Hone blasting is a cleaning method whereby a nonsilica material of 40-100 U.S. mesh size is blown through a %inch tungsten carbide nozzle at 30 psi. Silica (sand) of 70-100 U.S. mesh size can be used and is blown through a %6 -inch tungsten carbide nozzle at 60 to 70 psi. The hone blasting cleaning method is used by the U.S. Navy but is not currently in common use by the U.S. Army or commercial shipping industry. Blade surface areas which exhibit roughness after cleaning, because of cavitation or other conditions, should be polished by use of a 60-grit grinding disk. 203. Removal of Propellers In removing a propeller from the shaft, care must be taken to prevent damage to the shaft threads. Heat can be applied to the hub if necessary. a. To remove a propeller having tapped drawbolt holes, using a center bolt type puller, proceed as follows: (1) Remove fairwater nut or cone. (2) Loosen propeller nut a few turns. Note. Do not remove nut unless necessary for use of propeller puller. (3) Attach propeller puller with drawbolts (fig. 174). ( 4) Start removing propeller from shaft taper by tightening center bolt or puller. Caution: Each drawbolt must have sufficient thread in the propeller hub, or the tapped drawbolt hole will be stripped upon tightening the center bolt. ( 5) Remove propeller puller from propeller hub after loosening propeller and remove propeller. ( 6) Note that propeller pullers of the type shown in figure 17 4 can be made easily for different size propellers. The center hole in the strongback plate does not have to be tapped for the center bolt. A hole large enough to provide ample clearance for the center bolt shank can be drilled in the strongback plate, and a nut that fits Figure 174. Using a propeller puller. AGO 5244A the center bolt can either be tack welded to the side of the plate toward the propeller or held there and kept from turning wi·th a wrench. b. To remove a propeller having tapped drawbolt holes, using a drawbolt clamp and wedges, proceed as follows: (1) Loosen propeller nut a few turns. (2) Insert drawbolts in tapped holes in hub face. (3) Place a drawbolt clamp over end of shaft. ( 4) Interpose a pair of steel wedges between clamp and shaft end. (5) Set up on clamp nuts as tight as possible, then drive wedges until propeller loosens. (6) Remove wedges, drawbolt clamp, propeller nut, and propeller. c. To remove a propeller not provided with tapped drawbolt holes or for some single screw vessels where above procedure is not applicable, proceed as follows: (1) Install a shore between shaft coupling and forward side of stern tube to prevent strain on thrust or main bearings. (2) Loosen propeller nut. (3) Fill space between propeller hub and sternpost with metal blocking and a pair of metal wedges. Use two sets; one on top and one underneath. ( 4) Drive from opposite sides one wedge of each pair until the propeller starts moving. (5) Remove wedges, blocking, propeller nut, and propeller. 204. Straightening Bent Blades Normally a three-man crew is sufficient in propeller repair. The tools necessary for small craft propeller repair as a blacksmith's forge, an anvil, files, and an oxacetylene torch. Straightening and ·finish work can be conveniently and economically executed in the field. AGO 6244A a. Impor tanc e of Pr opeller Straightening. Straightening an(l balancing minimizes outboard bearing maintenance and avoids overloading engines, loss of efficiency and speed, and poor performance of misshaped propellers. b. H eating Propellers . Small bends or depressions in bronze propellers can be straightened while the propeller is cold. Because cold working hardens bronze, larged bends or irregularities must be repaired using heat to prevent cold cracks from occurring. When heat is used, heat propeller to a dull red color in a forge or with a gas flame. For overall heating where large surfaces are involved, the forge is faster and gives a more uniform application of heat. Figure 175 shows a propeller being heated with a forge. For small or localized repairs, a gas flame should be used. Caution: Bronze becomes weak at high temperatures and the propeller, if struck, can sag or break. Exercise care when handling or repairing a heated propeller. c. Straightening the Blade. On small propellers, tightly rolled bends are unrolled with blacksmith's tongs. Other irregularities are peened. It is advantageous to peen a bend on its concave or hollow side. On small propellers, strike the blade with a light hammer while backing the peening with the blade on an anvil. A typical peening operation is shown in figure 176. Large propellers are peened by using air hammers with a round edge calking tool. The metal unrolls like wet leather under Figure 175. Heating propeller with a forge. the hammer when the blade is at the correct temperature. Work should be stopped and the propeller reheated when the sound of the metal under the hammer changes from a dull, flat sound to a sharper, ringing sound. Several propellers can be heated and straightened at the same time. Most blades can be reshaped with two or three heatings. This can be done alt ernately so that the blade of one propeller is cooling while another is being heated and worked. In this way, the annealing is continuous, and no water cooling is necessary because a separate annealing step is not used. During straightening operations, the propeller should be compared occasionally to a propeller pitch block. d. Making and Using Pi tch Block. A pitch block can be made by pouring concrete in a plywood box and shaping the upper surface of the concrete to fit a new propeller. Figure 177 shows a badly damaged propeller on a block before straightening. Figure 178 shows the propeller on the pitch block after straightening. In figure 178, the upper edges of the Figure 176. P eening p1·opelle1· on anvil. blade are about an inch above the pitch block. This is because the pitch block is for a propeller with a pitch of 17 inches, whereas the propeller is a 24-inch diameter propeller with Figu1·e 177. Badly damaged propeller on pitch block. AGO 6244A a pitch of 18 inches. An efficient blacksmith with an eye for blade configuration can determine the amount of shaping and pitch alinement. e. Damaged, Notched Edges. The edges of the straightened propeller shown in figure 178 have notches. Normally notches of the size shown in figure 178 are not filled if other vessels are deadlined for repair. Damaged edge repair is covered in paragraph 205. 205. Repairs by Welding The location of the repair governs the kind of weld used and the care necessary. Root sections of the blade carry more stress than sections near the tip and therefore are critical. All metal deposits above the surface of the blade will have to be removed. a. Repair of Root Sections. Because of the high stresses on the blade between the hub and 0.4 radius, any repair in this area is considered major repair, and a welding procedure that can be depended upon to produce a strong, sound weld substantially free of residual stresses should be used. Metallic arc welding, multiple-layer gas welding, and the hot-flow process are approved methods for root section repair. b. Repair of Sections Outside the 0.4 Radius. Repairs in these areas are relatively minor and can be accomplished with the use of multiplelayer gas welding or metallic arc welding. Note. The use of silver brazing alloy or any other low temperature brazing alloy is not an approved method, as these alloys have insufficient hardness to resist the erosive action of high velocity water. (1) Repair of cav·itation pits . Cavitation pits can be weld~filled, using any approved method. (2) R epair of blade edges. Broken propeller edges can be replaced by welding a corresponding edge from a dispropeller (fig. 179). Cracks are ground or cut open and then welded together. The entire crack must be ground out or it will start cracking Figu1·e 178. P1·opeller on pitch block afte?' stmightening. AGO 5244A 227 again. If necessary, blades can be built up with the same welding rods used in the process of welding. Small notches in the edges are sometimes filled by welding. c. Finishing Weld ed Areas. Beads should be ground or filed smooth to match original surface contours. Splatter and flux should be removed by scraping, chipping, and/ or grinding or filing. Welded areas s hould be annealed if required. d. Metallic A rc W elding . For major or minor repair to manganese-bronze propellers, a covered aluminum-bronze electrode composed of 90 percent copper and 10 percent aluminum should be used. Phosphorous bronze rods should only be used for minor repairs, as these rods have only about one half the strength of the base metal. Each edge of the repair sections should be beveled 45 degrees (included angle 90 degrees) and the root of the bevel should be rounded to a minimum 1,4-inch radiu s; however, if the depth is over 1 inch, the sides can be beveled at 15 degrees after the width of the groove at the top exceeds 11/2 inches. The sec tion to be repaired should be chipped to sound metal and positioned for downhand welding. Welds can be made in the vertical position; however, suitable copper or carbon dams should be used to aid in supporting the weld metal. In order to obtain a proper joint, it is imperative that the base metal be locally preheated. The preheat temperature should be between 600 ° F. and 800 °F. (316 ° C. and 427 ° C.). In an emergency, a temperature of 400 °F. (204 ° C.) can be used. An approved rod of 1,4-, %6 -, or %-inch diameter should be used, especially on propeller sections over % inch thick. Smaller diameters, %2 inch and %6 inch, should not be used unless absolutely necessary, and then only when considerable preheating h as been done. With sufficient preheat, lower values of the cu r rent ranges recommended by the electrode manufacturer can be used. Although lower currents are desirable, the operator's skill and experience must be considered. Therefore, higher currents are preferable to currents too low. Higher currents risk fine porosity in the weld metal, but currents too low risk poor fusion and slag inclusions. Figut·e 179. Welding a replacement section to a propeller. AGO 5244A e. Hot-Flow Process. The hot-flow process provides a satisfactory method for major repairs. This process consists of flowing molten metal of approximately the same chemical composition as the base metal into the joint. This flow washes away and replaces the parent metal and forms a continuous member upon solidification. Foundry and mold equipment is necessary for the use of this process. f. Multiple-Layer Gas Welding. The multiple-layer gas welding method is an approved major and minor repairs of propellers. The edges to be welded are beveled to form a 75degree, single V-groove weld for thicknesses less than 1% inches. A 75-degree double V-groove is used if the thickness of the section is greater than 1% inches. A copper-zinc, lowfuming, welding rod of the proper size and in accordance with Military Specification MIL-R-19631 is used with a suitable brazing flux for repair of manganese-bronze propellers. A carefully adjusted oxidizing flame is essential for sound welds. A forehand method of welding should be used and the weld metal deposited in beads with limited oscillation not exceeding 1% times the diameter of the welding rod. g. Welding-Preheat and Stress Rel·ief. Because copper-zinc alloys are susceptible to stress-corrosion or season cracking, stress must be relieved, as the propeller can crack after being returned to service. The use of local preheat abov.e 400 °F. (204 9 C.), preferably between 600 °F. and 800 °F. (316 ° C. and 427 °C.), will preclude the accumulation of harmful stresses. Hot-flow welds and large gas welds are automatically preheated and slowly cooled, and stress relief can be safely omitted after welding. Arc welds and small gas welds should be preheated with a torch or other suitable means and then cooled slowly. If it is considered more desirable to stress relieve after welding, the following procedure is recommended. Heat slowly to 750 °F . (399 ° C.) and hold at this temperature for at least 1 hour per inch of thickness of metal in the welded area; cool slowly, approximately 2°F ., per minute, until metal is below 250 °F. ( 121 °C.) , after which air-cooling is permissable. During all preheating, welding, or stress relieving, the propeller should be well supported in order to avoid sagging and distortion. Repairs, particularly to AGO 5244A heavier sections of the propeller, should be performed with care in order to avoid thermal cracks or tears due to shrinkage stresses which can be imposed on the base metal. 206. Installation of Propellers All salt air and moisture must be excluded from void spaces of the propeller assembly. After installing the propeller assembly, make sure that it is tight. Proper attention to the details in installation instructions in the applicable technical manual will reduce the possibility of loss of the tail shaft or propeller. The propeller hub should be carefully fitted to the shaft taper and the fit checked with prussian blue. The standard shaft taper is 1 inch on the diameter per foot of shaft length. In final assembly the propeller is advanced beyond the mark at which an acceptable fit can be obtained. For bronze propellers with standard taper, the movement beyond the mark should be Ya 2 inch for each 5 inches of shaft diameter and 1 percent for each degree the fitting temperatur.e is below 60 °F . (15.6° C.). If the temperature is above 60° F. (15.6° C.), subtract 1 percent for each degree. For propellers with cast iron or cast steel hubs, the movement beyond the mark should be Ya 2 inch for each 5 inches of shaft diameter. For other tapers, the movement beyond the mark should be inversely proportional to the taper. Grease, oil, or other substances should not be used on the taper to facilitate driving up the propeller. Dry metalto-metal contact gives a better grip between hub and shaft. Cored holes in the hub should be filled with corrosion preventive compound, Military Specification MIL-C-11796, Class lA nonslick, before the propeller is installed on the shaft. If filling and vent holes have been provided in the hub, they can be filled after the propeller is installed. The space between the end of the shaft liner and the bottom of the propeller hub counterbore should be filled with a seamless soft rubber or neoprene ring for propellers that do not have an external packing gland. If an external packing gland is installed, the space between the ends of the hub counterbore and the annular space between the aft end of the shaft taped should be filled with corrosion preventive compound. The propeller nut and fairwater cone should be filled with corrosion preventive compound. Stu s and nuts, securing the hub cap and packing gland to the propeller hub, should be installed with a torque wrench and tightened dry so that they are within ± 5 percent of the specified torque in the applicable technical manual. 207. Propeller Measuring After Repairs Propellers should be measured with pitch blocks or a pitchometer and calipers to verify the ar.:curacy of repairs that have been made. Nominal decrease in blade thickness because of wear and erosion is acceptable, but the blade section contours should remain true. 208. Propeller Balancing Propellers and propeller caps should be balanced to insure freedom from vibration. A static roll balance is sufficient for propellers that rotate at a relatively low speed and have a small axial length in ratio to the diameter. Other propellers can require dynamic balancing. In static roll balancing a propeller, the propeller is mounted on a mandrel. The propeller shaft key should be included in the balancing. With the propeller mounted on the mandrel, the propeller is placed on two rails as shown in figure 180. The rails must be level, straight, and smooth. Material should be removed for balancing from the back or suction side of the blade over as large an area as practicable, but no closer to the blade edge than 10 percent of the blade's width. Weights can be welded to the inside of the propeller cap if Figure 180. Static balancing a p~·opeller using roll rails. necessary, providing they do not interfere with installation. When the propeller is correctly balanced, it can be stopped in any position of rotation on the balancing mechanism and released, and it will not roll back. Note. If available, a ball bearing, knife edge balancer should be u sed instead of roll rails. The knife edge balancer has greater sensitivity than roll rails. 209. Safety Precautions-General a. Application of H eat. During installation, it may be necessary to apply heat in order to obtain the proper advance up the shaft or to assist in removal of the taper propeller. Before applying heat, make sure that all propeller filling plugs and cover plates are removed and that adjacent shafting is protected from flame contact. Heat should be applied with two soft gas torches located on opposite sides so that the flame can be rotated for uniform heat and expansion. The temperature of manganesebronze propellers should not exceed 500 °F. (260 °C.) and should be checked at frequent intervals with tempil sticks or contact pyrometers. b. P1·otection of Propulsion Machine1·y. In order to prevent transmission of shock to reduction gears, rotors, or crankshafts when removing or replacing a propeller nut, a shore should be fitted from the bottom of the dock to a propeller blade near the root. The blade root should be protected by using chafing gear or softwood blocking. c. Handling PTopellen. In order to protect blade edges on a large propeller when turning it over, care must be exercised and softwood blocks used. Except when the propellers are crated, blade edges should be protected by canvas• and metal strips when they are shipped or moved. To lift a propeller, it is recommended that I-bolts, located in the hubs, be used with preventer straps placed around the blades. d. Exclusion of Water f r om Prop eller Bore. To avoid t he fracture of a shaft and possible loss of the propeller, the entry of sea water into the shaft and propeller assembly must be prevented. Therefore, it is ·essential that special attention be paid to the watertight integrity of the cap and gland sealing rings and to AGO 6244A filling the voids in the propeller assembly with rust-preventive compound. When propellers are installed on waterborne vessels, it is virtually impossible to exclude all salt water from the final assembly. For this reason and the increased possibility of propeller shaft failure, propellers should be changed under water only as a last resort. When propellers are changed on a waterborne vessel, the shaft should be inspected for corrosion and properly reinstalled at the next drydocking. e. Loss of Fairwater Cap. When the fairwater cap is lost, it should be replaced at the earliest opportunity. Rust-preventive compound, if exposed to the action of the sea, will wash away, causing acceleration of electrolytic corrosion of the propeller shaft taper and keeper key. This can cause loosening of the propeller nut and loss of the propeller; therefore, frequent checks of the propeller nut and keeper key should be made by divers until the fairwater cap is replaced. Section II. PROPELLER SHAFTS AND BEARINGS 210. Propulsion Shafting-General The primary purposes of propulsion shafting are to transfer the torque generated by the main engine to the propeller and to transmit the thrust developed by the propeller to the thrust bearing. Maintenance of shafts and bearings is the responsibility of the vessel engineer or dockyard machinist, not the hull repairman. However, the hull repairman will assist the engineer or machinist in the heating and straightening of struts and the heating of shaft sleeves and propeller when required for maintenance. a. Installation-Geneml. Shafting sections outside the skin of the vessel are usually supported by bearings located in struts, skegs, and stern tubes. On larger vessels, shafting is supported by line shaft spring bearings inside the vessel. To prevent the entry of water to the hull, a sealing system is installed in the area where the shafting pierces the hull. Some of the newer vessels are equipped with a split inflatable seal which is installed aft of the stuffing box and gland. These inflatable seals are used during repair or replacement of the main seals when the vessel is waterborne and the shaft is at rest. b. Propeller Shaft Removalr-General. Propeller shaft inspection and certification will be accomplished by the U.S. Coast Guard and American Bureau of Shipping, on U.S. Army vessels, by type and design as outlined in Army Regulation AR 750-1900-1. These inspection requirements state that propeller shafts fitted with continuous liners or approved lubricating systems will be removed at least once every 3 years. In some cases the propeller shafts will be removed every 2 years or more frequently if considered necessary by the inspectors. Consideration can be given to special circumstances such as vessels fitted with multiple propellers performing in scheduled operations or for shafts fitted with approved oil lubricated metal bearing arrangements where an approved modification is pending. American Bureau of Shipping defines allowable weardown of propeller shafts by the location of machinery. Where machinery is located amidships, the aft bearing is to be rebushed when it has worn down to lf.!, inch clearance in the case of shafts 9 inches or less in diameter, '(J fi inch clearance where shaft diameter is more than 9 inches but less than 12 inches, and % inch clearance for shafts exceeding 12 inches in diameter. When the machinery is located aft, the maximum clearances should be a grade less than the foregoing. Propeller shafts are removed when the shafts are bent, out of round, or cracked, or when excessive electrolytic action is present. Propeller shaft removal must be performed with extreme care to avoid bending or cracking the shaft. Removal should be made with hydraulic jacks or block and tackle methods. Care must be taken in separating connecting flanges so the machine facing will not be scored and to insure that no damage results to the struts, bearings, stuffing box, or steady bearing (fig. 181). c. Shafting Construction. Propulsion shafting for some vessels is forged in sections from alloy steel ingots and is sometimes hollow bored to save weight. The aft sections of the shaft are exposed to sea water and, when the vessel AGO 5244A AFTER ENGINE ROOM . FORWARD ENGINE. BULKHEAD--~ ROOM BULKHEAD PROPELLER NUT Figure 181. Propeller and shaft assembly. is dry docked, must be protected from salt water corrosion (pitting). These aft sections of shafting are protected by a rubber or plastic covering that is applied over exposed areas of the steel shafts (k· below). d. Pitted Shafting. Cases of severe pitting in outboard shafting, resulting from damaged or porous covering, should be reported to the appropriate authority who will decide whether the shaft is suitable for future service. If the pitted shafting is approved for reconditioning, the sharp edges of the pits should be well rounded by grinding and the corroded areas should be dressed down to the solid metal surface. Ground out pits and corroded areas, if extensive and of shallow depth, should be filled with approved cavity build-up material. Pits and corroded areas beyond allowable depths should be builtup by welding and covered with a protective rubber or plastic material. e. Vibration. If objectionable vibrations exist the shafting sections should be removed and checked for straightness. Dial indicator runouts of shafting ends, measured at the propeller or coupling tapers, should total less than 0.003 inch (0.0015-inch eccentricity), which should prevent excitation of the first-order vibrations (one vibration per shaft revolution). Runouts in excess of 0.003 inch total, giving an unacceptable performance, must be rectified or replaced by a new shaft section. f. Bent Shafting. Approval by the appropriate authority should be obtained prior to straightening severely bent shafting. Repair to the shafting section can be done by the spot heating method, or electric induction heating, 232 after which the shaft is straightened by mechanically controlled forces. g. Cmcks in Shafting. Cracks found in propulsion shafting should be thoroughly probed to determine the depth and length of the cracks. If shafting is determined to be repairable, weld crack by an approved method. h. Eccentr·icity. The dial indicator runout for any length of shafting, with respect to the axis of rotation and exclusive of journals and ends, should be limited to an eccentricity of approximately 0.003 inch. If, when the shafting is rotated 360 degrees, runouts greater than this figure are found, this eccentricity should be reduced to the lowest possible limit. A record should be kept of all installed shafting where eccentricities exceed 0.003 inch. Shafting should be replaced if objectionable vibration is still present. i. Electr·olytic Action. Zinc protector collars on the shafting should be replaced as necessary. Steel shafting that is exposed to sea water should be protected from electrolyte action by a rubber or plastic protective covering when electrolytic action occurs betwen the steel shaft and the bronze bearing journal sleeve (k below). j. Plugg·ing Shaft Ends. All shafting that is exposed to sea water and has been bored throughout its entire length must have both ends plugged to prevent water from seeping into the hollow shaft and into the vessel. One method is by tapping the shaft bore with a tapered pipe thread. In this method, a threaded plug is fitted and installed with thread compound to insure the watertightness of the plug. AGO 6244A As an alternative method, the shaft end can be counterbored and the plug machined for a shrink fit. The plug is then cooled to a low temperature and allowed to expand in the shaft bore. The plug in the aft end of the propeller shaft should always be threaded. At least one threaded plug is required in each section of outboard shafting to permit drainage of the condensed steam that occurs when a rubber covering is used to permit the application of rust-preventive compound. One end of each section of inboard shafting should be plugged. k. Shaft Covering and Insulation. (1) Preservation. In order to adequately preserve the water-lubricated stern tube and strut bearings of reserve fleet vessels, a leakproof seal and an effective preservative compound must be employed. A leakproof seal must be provided which will prevent the entrance of foul and silt-laden water and its various contaminants and retain the preservative compound in the bearings during inactive status of the vessel. The procedure described below should be followed to provide divers with a standard method of removal upon activation. The propulsion bearing seals should be installed after a positive lock has been secured on the shafts to prevent accidental turning of the shaft when the vessel is under tow. The basic materials used are sheet rubber, Military Specification MIL-S-15058, type III, and phosphorous bronze flexible cables and cable terminals. Flexible cables are used to help secure the ends of the cemented rubber boot to the shaft, strut barrel, propeller hub, or stern tube extension. The seal will have an outer protective jacket consisting of a laced-on corset of vinyl or neoprenecoated nylon cloth (fig. 182). (2) Preservative compound. A preservative compound that will be light in viscosity and penetrate all bearing voids such as clearance spaces and / Figure 182. Typical laced boot with oil fittings. AGO 5244A lubricating grooves must be employed. In use, it must effectively protect all bearing and journal surfaces to prevent chemical and electrolytic corrosion and to displace all sea water. The preservative compound used must also provide the bearing with initial lubrication and must be capable of being flushed out of the bearings upon activation of the vessel. (3) Principle of construction. Bearing preservation by the sheet rubber method involves the following: (a) Inspection and cleaning of the bearings prior to preservation. (b) Structural modi,fications involving the construction of a circular metal band or rubber band to provide a smooth gasket sealing surface for one end of the boot. The other end of t~e boot is sealed onto the shaft after cementing a rubber band over the shaft. (c) Determination of the size and shape of the rubber boot to be cut from sheet rubber. (d) Construction of the lap seam of the boot by skiving, overlapping the edges, and cementing together. (e) Cementing the ends of the boot to the shaft and to one of the structural modifications on the strut barrel, propeller hub, or stern tube extension. {f) Clamping the two ends of the rubber boot. (g) Testing the boot for leaks. (h) Lacing on the outer jacket of vinyl or neoprene-coated glasscloth. ( i) Filling the rubber boot wi,th rustpreventive solution so that the bearings are immersed (fig. 183). 211. Shaft Couplings-General The shaft coupling is used for the connection of two separate parts of the shaft or the con- Figure 183. Typical boot with clamps and oil fitting. AGO 624U nection of the shaft to the main engine. This is accomplished through connecting nuts and flanges which are locked in place with setscrews, locking keys, or locking plates (fig. 184). a. Fitted Flanges. The ends of the propulsion shafting sections are usually provided with integral flanges for coupling together the adjacent shaft sections by coupling bolts. The face of each half coupling flange must be finished truly perpendicular to the axis of the shaft. The outer peripheries of each of the matched flange coupling halves must be concentric. For fitting together flanges of two adjacent sections, two different bolting systems can be used: a hex or round (with flats) headed, straight-fitted bolt, backed up by a standard nut and cotter pin; or, preferably, a hex or round (with flats) headed bolt with a body taper of 1/s inch per foot, backed up by a standard nut or cotter pin. Using these approved designs with upset heads reduces the danger of pulling headless taper bolts through the flanges when backdriving the vessel, which could result in casting the shafting adrift. In all cases when fitting the flange bolts to their particular flanges, a system of permanently marking the bolt location in the flange must be used in order to insure the proper fit of the flanges after repair of the shaft (fig. 185). b. Couplings and Shafting Exposed to Sen Water. The aft section of the shafting which is exposed to sea water and inaccessible except COUPLING AND FLANGE Figure 184. Typical shaft coupling with retaining nut and flange. AGO 5244A Figure 185. Ty]Jical fitted flange and cou]Jling. when the vessel is drydocked must be protected from salt water and corrosion (pitting). The aft sections of shafting are protected by a rubber or plastic covering applied over the exposed area of the steel shafts. Information on rubber boots and covering of shafts, couplings and flanges, and propeller shafts and bearings, is contained in paragraph 210k. c. Inbonrd Flange Coupling. The makeup and connection of inboard flange couplings have been covered with the following exception: some shafts are equipped with keyways and removable couplings, line shaft bearings, or line shaft spring bearings. The bearings are generally of the ring oil type, with top and bottom babbitt-faced removable shells that are mounted on spherical se~ts. The bearings should be temperature-checked hourly while underway and examined annually for defects. 212. Shaft Journals-General A shaft journal is that part of the shaft supported by a bearing. A shaft journal is lubricated either with oil or with water. Any time a shaft bearing is removed, a support must be used to hold the shaft to prevent bending or misalinement which would result in excessive shaft vibration. a. Journal Sur"[aces. When shaft bearings are removed, the following steps should be performed for journal surface care: (1) Examine condition of journal as each bearing is removed. (2) Stone and polish or roll and polish journal if scored lightly. (3) Restore journal to design diameter by chromium plating and grinding if journal is badly scored; or it can be ground undersize. (4) Take precautions to maintain concentricity with bearing if journals are machined. Check balance after machining is completed. b. Care of Journals. Journals should be kept smooth and even at all times and kept free from rust and products of corrosion. To remove spots of rus~t, ridges, and 'Sharp edges of scores, the journals should be lapped with an oil stone or with an oilstone powder. Carborundum can be used if care is taken to remove all particles after lapping. c. Installation of Shaft Keys. Keys and keyways in shafting, propeller hubs, and couplings (inboard and outboard) must be fitted closely and a press fit used in the installation (fig. 185). Drilling for retainer screws is not required. Drilling for a dowel pin to keep the keys from sliding, when installing propellers and couplings, is required. Key corners are to be chamfered 45 degrees and the keyways should have well-rounded corner fillets, preferably with the radius of the fillet amounting to about 3 percent of the shaft diameter. Keys should be made from the same basic material used for the shafting and the couplings. The dimensions and the sectional area of the keys should provide sufficient strength to carry the entire load and to comply with the designed working stress of the particular installation. 213. Alinement of Shafting and BearingsGeneral The alinement of shafting and bearings will change wi,th every docking. The alinement of the struts and stern tubes, in relation to each other as well as their alinement with the main propelling machinery, will undergo a natural change if the propeller, propeller shaft, line shaft, and/or bearings are removed. Due to changes in weight loads and stresses, the alinement of shafting and bearings is affected by the removal of machinery either attached to them or in their vicinity. It is particularly important to check for correct shaft and bearing alinement after an engine change, as in a land ing craft. Alinement conditions will vary and depend upon whether the vessel is waterborne, whether the vessel rides in the hollow or crest of the wave, and loading conditions of the vessel. The final alinement of the main propulsion shafting should be done when the vessel is waterborne. a. Importance of Correct Alinement. Correct alinement is necessary to eliminate shaftexcited vibrations and prevent excessive pressure on any localized portion of the shaft bearing surfaces. The longitudinal line, connecting the lowest extremities of all shafting journals having the same diameter, should form a continuous faired line when the machinery is at operating temperature. If the shafting, when at rest, is correctly alined, the bottoms of the shaft journals should be in contact with the bearing material and the bearing clearance at the horizontal centerline of the journal, should be equally divided. The loads should be of the same magnitude as determined by the theoretical bearing reaction calculations. b. Maintaining Alinement. Alinement or sag charts have been prepared for most vessels to show the relative flange positions and angular slopes of shafting when the coupling bolts have been removed. With the bearings adjusted to conform to these charts and the couplings bolted up, proper alinement of the shafting is assured. c. Running a Line Wire. The proper location of the bearings on main propulsion shafting can be checked by running a line wire. There should be no sag in the wire and it should be approximately horizontal for best results. Running a line wire consists of installing supports just clear of the ends of the outer bearings of the set to be lined up and stretching a length of No. 6 music wire with a 30-pound weight attached between the supports. The wire should be attached to the supports in such a way that it can be accurately centered in the reference bearings and firmly held in this position by the supports. After it is centered in the end bearings and corrected for sag, the wire forms the line of reference for all intervening bearings. Refer to .table XII. d. Optical Method of Alining Shafting. Alinement of shafting by the optical method makes AG0,5244A >8 ~.. > Table XII. Sag of No. 6 Music Wire Distance from support (feet) 12 14 16 18 20 22 24 26 Distance between supports (feet) 28 30 32 34 36 38 40 42 44 46 48 60 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 1.5 2 2 2.5 3 3.5 4 4.5 4 5 5.5 6.5 4.5 6 7 8 5 6.5 8 9.5 5.5 7 9 10.5 ---7 9 11.5 -------9.5 11.5 --------·---12 --------------------------------------------------------------------------·---------------------------------------------------------------------------------------------------------------------------------------------------------------------- 3 5.5 7.5 9.5 11 12.5 13.5 14 14.5 14.5 --------------------------------------------- 3 3.5 3.5 6 6.5 7 8.5 9 10 10.5 11.5 13 12.5 14 15.5 14 16 17.5 15.5 17.5 19.5 16.5 19 21 17 20 22.5 17.5 20.5 23.5 17.5 21 . 24 ---21 24.5 --------25 ------·----------------------------------------------------------------------·--------___,_ -------------------------------------------- 4 4.5 3.5 3.5 4 7.5 8.0 7 7.5 8 11 12 10.5 11 11.5 14 15 13.5 14 15 17 18.5 16.5 17 18.5 19.5 21 19.5 20 21 21.5 23.5 22 ~· 23 ; 24 23.5 26 25 26 27 25 27.5 27.5 29 30 26.5 29.5 29.5 31.5 33 27.5 30.5 31.5 33.5 35.5 28 31.5 33.5 35.5 37.5 28.5 32.5 35 37.5 39.5 28.5 33 36.5 39 41.5 ----33 37.5 40.5 43 ---------38 41 44 ------------42 45 ----------------45.5 -------------------------------------------------------------------------------------------------------------------------------------------- 4 8 12 15.5 16.5 22.5 25.5 28.5 31.5 34.5 37 39.5 42 44 45.5 47 48 48.5 49 ----------------------- 4 8 12 16 20 23.5 27 30 33 36 39 41.5 44 46 48 49.5 51 52 52.5 52.5 --------------- 4.5 9 13 17 21 24.5 28 31.5 34.5 37.5 40.5 43.5 46 48 50 52 53.5 55 55.5 56 56 ---------------- 5 9.5 13.5 18 22 26 29.5 33 36.5 39.5 42.5 45 47.5 50 52 54 56 57.5 58.5 59.5 60 60 ------------ 5 9.5 14 19 23 27 31 35 38 41 44 47 50 52 54 56 58 59.5 61 62 63 63.5 63.5 -------- 5 10 15 20 24.5 28.5 32.5 36.5 39.5 43 46 49 51.5 54 56 58 60 61.5 62.5 64 65 66 66.5 67 --- 5.5 11 16 21 25.5 29 34 38 41 44.5 47.5 50.5 53 55.5 58 60 62 63.5 65 66.5 68 69 69.5 70 70.5 Note. Tight wire sag data, showing allowance thousandths of an ineh)• to be made for sag in alinement wire when using 0.0166-inch wire (No. 6 music wire) and SO-pound weight (sag in .., w ... use of sight which, for all practical purposes, IS a true line. Using this method eliminates many steps in alinement where errors could occur and, at the same time, aids greatly in speeding up and checking the alinement. e. Alinement Using Feeler Gages and Shims. Testing and correcting alinement of flanges and couplings can be accomplished by using feeler gages of various thicknesses and shims. Correcting misalinement is only a matter of alining the engine to the propeller shaft keeping all flanges square and even. At the same time the feeler gage, of the correct thickness should be equally tight at all points around th~ coupling. A small clearance around the engine holddown bolts should be provided to allow slight movement of the engine during alinement. All close testing must be done with the holddown bolts tightly secured to keep the engine firm on its foundation. A perfect shaft alinement is not as simple as it can seem. Additional shim:r;ning or cutting down of the foundation and several tests after tightening the bolts are necessary. When the flange is open on the bottom, it can be necessary to shim aft or lower the forward end of the shaft or both. Side alinement can be corrected by shifting the engine horizontally after vertical alinement is correct. When the feeler gage feels the same all around and the holddown bolts are tight, the alinement is correct. Do not use flange bolts while testing. Push the flanges together without force. Four strips of paper equally spaced can be used between the flanges for testing purposes. Alinement is correct when tension is the same on all four strips. Thick hardwood shim should be used when alining. Shims of galvanized sheet metal of various thicknesses and slotted to slip around the holddown bolts will be very satisfactory while alining. These slotted shims can be installed permanently. When performing shaft alinement, always work from the stern bearing toward the engine, alining the engine last. f. Final Alinement. The final alinement of the shafting is accomplished after the vessel is waterborne. This is dope by slightly shifting the line shaft bearings until the drops and openings of the uncoupled mating shaft flanges are as calculated. 214. Bearings-General Bearings are used to guide and support reciprocating and rotating elements. The elements or members subject to external loads can be resolved into components having normal, radial, and axial directions, or a combination of two-dimensional loading. a. Sliding Surface Bearings. A journal bearing is an example of a sliding surface bearing. An oil film provides the best lubrication for sliding surface bearings; however, grease is often used. Propulsion shaft bearings exposed to sea water are usually lubricated with water. b. Radial Bearings. Radial bearings are designed to carry loads in a plane perpendicular to the axis of the shaft. They are used to prevent movement in a radial direction. The simplest forms of radial bearings are the integral and insert types. The integral type is formed by surfacing a part of the machine frame with the bearing material. The insert bearing is a plain bushing that is held in place in the machine frame. The insert solid bushing type and the integral type have no means for adjustment. They must be replaced when wear reaches the point of maximum clearance. The split type allows for adjustment by removal of shims. c. Thrust Bearings. Thrust bearings are designed to take loads applied in the same direction as the axis of the shaft. They are used to prevent free end movement. The pivot or single disk type bearing is a simple thrust bearing consisting of the end of a journal extending into a cup-shaped housing. The housing bottom holds the single disk of bearing material. ( 1) The multidisk type thrust bearing consists of several disks, usually alternating bronze and steel, which are placed between the end of the journal and the housing of the bearing. The intermediate disks are free, the lower disk is fastened to the housing, and the upper disk is fastened to the journal. (2) The multicollar thrust bearing consists of a journal with thrust collars, integral with or fastened to the shaft, fitted into bearing metal-faced recesses in the bearing housing. AGO 5244A (3) Pivoted-shoe type thrust bearings are usually designed for both directions of rotation. A thrust collar, fixed to the shaft, turns against the pivoted shoes. d. Radial-Thrust Bearings. Radial-thrust bearings are designed to carry a combination of radial and thrust loads. This is usually done by using a radial-type bearing to restrain the radial load and a thrust bearing to handle the thrust load or by using a bearing that combines the functions of the two. A typical example of the combination type of bearing is the multicollar bearing which has its recesses entirely surfaced with bearing material. The faces of the collars carry the thrust load and the cylindrical edge surfaces handle the radial load. e. Application of Bearings. (1) Main pr-opulsion stern tube and strut bearings. Stern tube bearings generally consist of bronze shells, in halves, lined with a suitable bearing wearing material. Bearing shells are normally grooved longitudinally to receive the wearing material. Wearing materials are strips of lignum vitae, laminated resin bonded composition which is faced with natural or synthetic rubber compounds. The lignum vitae and laminated strips are cut and installed in the bearing shells so that the end grain is presented to the shaft. In some installations, solid packed strip wood, resin bonded composition bearings, or full-molded type rubber-faced bearings are used. Strut bearings are similar to stern tube bearings and made of the same material. When a bearing must be renewed, consideration should be given to renewal of other bearings on the same shaft to avoid misalinement. Water can be supplied to the stern tube bearings by either 10 psi, continuously forced flow through the flushing connection located at the forward end of the stern tube, or by natural pressure circulation. When the method of forced water lubrication is used, the flushing valve should be opened prior to getting underway. When the vessel is underway and natural water circulation is employed, the packing gland should be sufficiently slackened to allow a thin stream of water to trickle by. The leakage of water through the stern tube stuffing box is the only available indication of a flow of water for cooling and lubricating the bearing wearing material. The glands, during anchoring, should not be disturbed unless leakage becomes excessive. As a means of assuring positive water lubrication to the forward stern tube bearing during turbine warmup periods or other periods when natural circulation is doubtful, fire main or circulating water should be forced through the flushing connection on the inboard end of the stern tube stuffing box. (2) Main JJropulsion line shaft spring bearings. These bearings are usually of the ring-oiled type and have top and bottom babbitt-faced removable shells or brasses that are mounted on spherical seats. They are to be treated the same as other babbit-faced sliding surface bearings, and, when underway, their temperature should be checked every hour. (3) Main propulsion thrust bearings. This bearing, in its simplest form, consists of several pivoted segments or shoes against which the thrust collar turns, thus restraining the fore-and-aft axial motion of the shaft by the action of the thrust shoes against the thrust collar. The shoes and collar, encased in a housing, are immersed in oil for protection. (ct) In a segmental, pivoted-shoe type thrust bearing, pressure is equally distributed among the entire set of shoes by the action of leveling blocks. The removal of any shoe or shoes from the set breaks the chain of leveling blocks, causing the ends of the blocks supporting the shoe or shoes to be jammed against the base ring which destroys the bal- AGO 6244A ancing effect. It is necessary that each half of the base ring rest against the housing in order that each shoe can assume its share of the pressure. In some types of bearings, the base rings are designed to have the joint in a practically horizontal position. When the top half of the housing is removed from this type bearing to make the collar accessible, the upper half of the base ring has no support. When adjusting the thrust of this type bearing, the base ring should be temporarily installed with the joint vertical. Each half of the base ring then takes up against the bottom half of the housing, and the entire thrust is compressed between the flat parallel surfaces of the thrust collar and housing. The shoes and leveling blocks then assume the same position as with the top half of the housing in place. The faces of the shoes will adjust themselves to any small angle relative to the base ring, and pressure on any one shoe is distributed to all. This type of bearing should not be adjusted by applying shims behind the base rings. (b) Frequently, a set of shoes is slightly burnished or worn away. If this happens and no spares are available but the shoes are interchangeable, change the astern shoes with those of the ahead side. Stone out any ridges cut in the collar carefully, as the tolerance recommended is 0.001 per inch of collar diameter. Spot in the worn shoes and install on the astern side, leaving a Yt6 -inch, 30degree bevel on the entering edges of the shoes; otherwise, the sharp edge will tend to scrape the oil film from the collar. If the collar has been badly scored, refinish the surface. The final operation must be a fine lap to achieve a maximum surface roughness of 16 microinches. The applicable technical manual should be consulted regarding maximum and m1mmum allowable oil clearances on thrust bearings. If this information is not available, the minimum thrust clearance can be taken as 0.001 inch times diameter of the collar in inches. The maximum thrust bearing clearance should be less than the minimum axial clearance of connected machinery units, such as turbine blade clearance, or minimum axial clearance between the fins of turbine labyrinth packing. (c) On small vessels, thrust is frequently taken by a simpler type of thrust bearing, normally located between the propeller and the transmission on the shaft, shaft coupling, or rear assembly of the transmission. (4) Rudder bearings. Rudder bearings transmit forces to the hull that are generated by the weight of the rudder and its accessories, by the steering system, and by the drag through the water. Both sliding-surface and rolling-contact type bearings are used for rudder bearings, and sometimes combinations of the two types are used. Sliding-surface type rudder bearings can be used to take radial forces and carry the weight of the rudder. On large vessels, the radial rudder bearing usually consists of a bronze bushing, split on the centerline for ease of removal, and is fitted with a solid pack nesting of staves made from laminated, resin-bonded, composition wearing material. Radial bearings, inside the hull and free from sea water exposure, are grease or oil lubricated. The bearings mounted in gudgeons, attached to the stern casting outside the hull, are lubricated by grease, water, or a combination of both. The rudder carrier bearing is usually a laminated phenolic, bronze, or babbittfaced vertical thrust bearing of the plain-disk type. In rudder bearings, the characteristic low speed rotation with high-bearing loading makes heat AGO 5244A generation of slight consequence and wear or material deformation of major consequence. Spherical, roller-type bearings are often used for both radial ;nd carrier bearings, as the selfalining feature enables the bearing to adjust itself to normal hull and stock deformations. One arrangement has the upper bearing fixed while the lower bearing is axially unrestrained; the lower bearing accepts only radial loads. In another arrangement, the order is reversed; the lower bearing is fixed and the upper bearing is axially unrestrained. In either arrangement, the lubrication sealing mechanism for the upper bearing is accomplished by either a packing gland or a mechanical (Syntron) seal. 215. Bearing Requirements-General The basic design of a bearing depends upon the magnitude and direction of the load on the bearing and upon the relative speed between the bearing surfaces. The length of the bearing determined by maximum rubbing speed, allowable load per square inch of bearing contact area, and requirements for strength and rigidity. The radial dimension of the bearing is fixed by the diameter of the journal. The proper bearing material is selected with respect to the load on the bearing, the heat generated,· and the material used for the journal. A satisfactory method of fixing bearing wearing material into the bearing must be provided, and provisions must be made to take up wear and increased clearances as they occur. The design and installation should provide a way to change the positioning of the bearings in cases where misalinement could occur between the journal and bearing. a. Bearing Material. The replacement, repair, and maintenance costs of bearing material should not be excessive. Molded plastics, rubbers, and lignum vitae do not meet all of these requirements; however, under certain conditions of application, these types of materials offer enough additional advantages to warrant their use as bearing materials. A good bearing material should possess the following qualities: AGO 5244A (1) Easy availability and strength. (2) Practical service and maintenance. (3) Uniformity. ( 4) A low coefficient of friction. ( 5) High heat conduction and resistance. ( 6) Sufficient hardness to resist abrasion. (7) Impact resistance (yet not brittle). b. Lubrication Provisions. There are several ways of providing lubricant to bearings. The following are most frequently used: (1) Drop-feed lubrication which consists of feeding the lubricant a drop at a time through a hole in the bearing. (2) Wick lubrication which uses oil carried from an outside reservoir to the bearing surface by capillary action in the wick. (3) Ring lubrication which uses oil picked up by a ring and carries it to the shaft as the ring rotates with the shaft. The quantity of oil delivered to the journal depends upon the size and speed of the ring and the viscosity of the oil. ( 4) Disk lubrication which uses oil picked up by a rotating disk clamped to the shaft and directs the oil to the bearing surface by a wiper fitted to the upper shell. ( 5) Flood lubrication which has the bearing completely immersed in a bath of oil at all times. (6) Pressure lubrication which furnishes oil under pressure to the bearings through pipes or passages. c. Grooving of Bearings. After the lubricant is delivered to the bearing, distribution within the bearing is made by grooves in the bearing. The lubricant should enter the bearing at a point of minimum pressure. Depending upon design of the bearing, grooves in the bearing take several forms. The simplest are the axial and the circumferential grooves, and either of these can be modified or used in combination to give desired lubrication delivery within the bearing. Sometimes circumferential grooves are placed at the ends of the bearings as a controlling device for preventing side leakage, but this use does nothing to distribute the lubricant. When grooves are machined into 'a bearing, care should be taken in beveling the groove into the bearing surfaces so that a constriction will not result. This type bearing groove should not be changed from the original design unless warranted by continuous trouble from improper lubricant distribution within the bearing. The bearing must be fitted with a radius larger than that of the journal to allow circulation of lubricant and the formation of a film between the journal and the bearing. This difference allows a certain amount of play between the journal and the bearing and is called the BEARING CLEARANCE. Clearance must be uniform along the entire length of the bearing, except for large bearings. Large bearings have a slightly larger clearance at the sides near the joint. The beveled sides of a bearing prevent nipping of the journal if the bearing runs warm. This facilitates handling the bearing on and off the journal during the process of fitting and permits a better distribution of lubricant for cooling. If the clearance is not uniform throughout, only part of the bearing surface takes the load. The friction on this limited surface will tend to cause the bearing to run warmer than normal, which could result in failure. In assembling a bearing, the butting faces of the shells must be set up metal to metal. The result desired is to reduce bearing clearance to a minimum but, at the same time, insure sufficient flow of lubricant to prevent overheating. d. Bearing Clearances and Factors Governing Clearance. The amount of clearance to be provided depends upon the size of the bearing, the accuracy af shaft alinement, the speed of revolution, the desired operating temperature, and the viscosity of the lubricant. It also depends upon whether the direction of the load force alternates or remains constant or whether gravity or forced lubrication is used. 216. Maintenance of Bearings-General Bearings should be kept within specified tolerances given in applicable technical manuals. a. Procedure When Bearings Overheat. A small rise in temperature is advantageous, as it decreases the viscosity of the lubricant and lessens internal friction. If the temperature of a bearing increases above its normal running temperature, the quality and quantity of the lubricant supplied should be checked. The supply should be increased by opening the needle valve, if one is provided, or by increasing the delivery pressure of the oil pumps. The lubricant should be further cooled by increasing the flow of circulating water to the coolers. If these measures are not effective, the speed of the unit should be reduced or the unit shut down. The bearing should not be sprayed with water except in case of emergency, as water causes contraction and further reduces the clearance. Generally, hot bearings can be traced to several possible causes. Refer to table XIII for the causes and remedies of hot bearings. A bearing being used for the first time should be used at low speed, and oil temperature should be observed at frequent intervals. Injury to the rubbing surfaces of the bearing will be indicated by a rapid rise in temperature of the outlet oil. A temperature rise of more than 1°F. (0.56°C.) per minute usually indicates that the rubbing surfaces have been scored. When this occurs, the bearing should be taken apart and examined. A run of about 10 minutes is usually sufficient to determine the rate of temperature . change, and if any cutting occurs at low speed, Table XIII. Bearing Troubleshooting Chart Trouble Probable cause Remedy Hot bearings _________ Improper or insufficient lubrication __ _ Add abundant supply of lubricant. Grit or dirt in bearing _______________ Flush out with increased supply of lubri cant. Foreign matter in lubricant _________ Renovate or renew lubricant. Bearings out of line, improperly fitted, Operate at reduced power until proper ad or not in proper condition. justments or repairs can be made. Workload on bearing too great ________ Adjust independent link-up gear. AGO li244A the face will not be seriously injured. If the babbitt is wiped, carefully scrape away the metal and remove any high spots. Be careful to remove only a very small amount of the metal at a time and avoid the forming of ridges. b. Wiped Bearings. Once a bearing has been wiped, it should be reconditioned at the first opportunity. If it has been slightly wiped, it can probably be scraped to a good bearing surface and restored to service. If badly wiped, the bearing will require replacement. c. Rebabbiting. A bearing which has been wiped beyond restoration must be replaced. ThP following procedures can be used to rehabbitt bearings. ( 1) Machine out all old lining to base metal of shell. (2) Wash shell in hot alkaline cleaner solution consisting of 4 to 6 ounces Oakite to 1 gallon of water. A weak lye solution can be used if Oakite is not available. (3) Rinse shell in fresh water. Do not touch that part of shell to be tinned with hands or any oily substance. 4) Dip shell in cold (20 to 25 percent) hydrochloric acid solution for approximately 5 to 10 minutes. If no bath is available, this solution can be swabbed or painted on area to be tinned. (5) Rinse with fresh water. ( 6) Plug all holes in shell with dry asbestos or magnesia. (7) Coat all surfaces of shell which are not to be tinned with a fire-clay wash. (8) Brush or swab surface of shell that is to be tinned with flux (zinc chloride and water in equal parts by weight). (9) Immerse shell in bath of molten solder held at a temperature of 575°F. (302°C.) minimum to 625°F. (330°C.) maximum. Keep shell in bath until it has reached bath temperature. (10) Remove shell and inspect tinned surface for flaws; scrape and reflux poorly tinned areas and return shell to solder bath. ( 11) Remove bearing from bath, shake off excess solder, set in jig, and pour babbitt as soon as possible, preferably within 2 minutes. The timed surface should be preheated with a torch to above 600°F. (316°C.) so that babbitt will begin to solidify at bond rather than at mandrel. This prevents pulling away of babbitt from the bond during solidification. If a wooden mandrel is used, no preheating is necessary. (12) Pour babbitt into space between shell and mandrel. Navy No. 2 babbitts should be at a temperature between 800° and 850°F. (427° and 454°C.), with a bottom pour ladle preferred. If this ladle is not available, a common ladle can be used, taking care to keep surface of molten metal bright and free from oxides by skimming. ( 13) Cool assembly from outside and bottom by air blast or sprinkling can. Puddle molten metal with iron wire during cooling to prevent formation of shrinking cavities. (14) Note, after solidification, that the sides of the shell have been drawn together by shrinkage of the lining. These can be brought to their original dimensions by peening the inner surface of the lining. ( 15) Observe that figure 186 shows a simple jig suitable for rebabbitting bearings. The two halves of the bearing are wired together before tinning, with a Vs-to 1,4-inch spacer with pieces of metal wrapped in asbestos paper between them. The mandrel is through-bolted to a metal plate. The bearing is placed in position over the mandrel with asbestos paper between the plate. The pouring lip is placed on the upper end of the bearing. This lip is a ring of either wood or metal about %, to 1 inch thick. The cross bar is placed on the center bolt and secured AGO 5244A 243 with a nut. Wooden wedges are driven between the cross bar and the pouring lip, and the molten babbitt is poured in. After solidification, the spacers between the bearing halves are removed and the halves separated by sawing through the babbitt to the mandrel on each side. (16) Note that when a bearing is rehabbitted, it must be verified that the bearing is in accordance with drawing or applicable requirements, and that a good bond exists between babbitt and shell by sounding with a hammer. d. Maintenance Inspection. Inspect all bearings as outlined in applicable technical manuals. If the bearing is scored, uneven, or worn beyond limits or if lining is loose, the bearing should be replaced. Rudder bearings should be inspected as follows: POURING LIP-WOOD OR MET ( 1) All rudder bearings requiring lubrication should have the bearing rings, the area between roll rings, and separators completely packed with the required grease specified in the applicable technical manual. (2) The housings should then be completely filled to aid in preserving and sealing the housing against moisture. Note. If grease is found to be oxidized or discolored during inspection, it should be removed and replaced with new grease. (3) Rolling contact bearings showing evidence of wear indicate the presence of contamination. Uniform wear does not affect the load carrying function of the bearing; however, the integrity of the sealing mechanism can be seriously affected if the original mounted clearance of the bearing is exceeded by a factor of 3 or 4. DAM-WET SAND OR FIRE CLAY METAL BASE PLATE Figure 186. Rig for rebabbitting bearings. AGO 5244A Table XIV. Recommended Clearances for Rudder Bearings. A B c Outside diameter Maximum allowable of stock or pintle Minimum operating diametric clearance including sleeve diameter clearance at which bearing (journal diameter) (See notes) should be renewed (inches) (inches) (inches) 1 0.005 0.05 2 0.005 0.05 3 0.006 0.06 4 0.006 0.06 5 0.007 0.06 6 0.008 0.06 7 0.009 0.06 8 0.010 0.07 9 0.011 0.07 10 0.012 0.07 11 0.013 0.07 12 0.014 O.o7 13 0.015 0.08 14 0.016 0.08 15 0.017 0.08 16 0.08 17 0.019 0.08 18 0.020 0.09 19 0.021 0.09 20 0.022 0.09 21 0.023 0.09 22 0.024 0.09 23 0.025 0.10 24 0.026 0.10 25 0.027 0.10 26 0.028 0.10 27 0.029 0.10 28 0.030 0.11 29 0.031 0.11 30 0.032 0.11 31 0.033 0.12 32 0.034 0.12 33 0.035 0.13 34 0.036 0.14 35 0.037 0.15 36 0.038 0.16 0.018 Note 1. The values in column B are minimum operating diamet ric clearances fOil" the wet installation of lignum vitae and laminated phenolic bearing materials. The values also apply to metal bearing materials which are not dimensionally changed due to water absorp tion. Suitable diametric swelling allowance for bearing wearing materials, which expand due to water absorption, must be added. The allowances for these materials are as follows: allow 1 percent of the total wearing material thickness for stave-type bearings with cotton fiber laminations that are perpendicular to the journal surface (this 1-percent allowance should be added to column B) ; allow 3 percent of the total material thickness for stave-, segment-, or tube-type bearings with cotton fiber laminations that are either parallel or concentric to the journal surface (this 3-percent allowance should be added to column B). Note l!. In measuring clearances of bearings, take readings with dial gage with the stock jacked forward, aft. to port, and to starboard. If dial gage readings at a given bearing indicate an excessive amount of bearing wear, that particular bearing should be renewed. AGO 5244A Note 9. When laminated phenolic or lignum vitae bearing mate rial is installed wet, no allowance for diametrical, longitudinal, or circumferential swelling will be necessary. Wet installation of lignum vitae bearings is the only acceptable method of installation of this rnaterial. Note 4. When the maximum allowable clearance given in column C is exceeded, replacement of bearings is necessary. This should be done if theroe is evidence of excessive leakage at the stuffing boxes, excessive noise, chatter, or vibration, or other undesirable effects attributable to excessive bearing clearances. The bearings should be renewed even though the maximum allowable clearances are not exceeded. Note 5. Laminated phenolic material should conform to Military Specification MIL-P-18324. In stave form, it should be installed with the edges of cotton fiber laminations perpendicular to the journal surface. When laminated phenolic material is installed dry, the swelling allowances specified in Note 1 should be applied to correct for diametrieal, longitudinal, and ci:reumferential swell ing of the material. ( 4) Check exposed rolling surfaces of bearings for evidence of spalling or pitting by drawing an improvised stylus across exposed surfaces of rollers and those surfaces of the bearing rings which are adjacent to rollers. If spalling or pitting is detected, remove rudder stock and perform a more detailed inspection of bearings. (5) Technical manuals or vessel plans should be consulted for bearing clearance, details of operation, adjustment, and care of systems containing special lubrication instructions or special sealing mechanisms. In the . event specifications cannot be found outlining the installation of rudder bearings, table XIV can be used as a guide to determine maximum and minimum installation clearances. e. Rolling Out Lower Ha-lves. If difficulty is experienced in rolling out the lower half of a bearing, it can be started by placing a zinc slab edgewise on one side of the joint where the bearing halves meet and striking the slab with a maul. f. Treatment of Journals. Journals should be kept smooth, even, and free from rust at all times. To remove spots of rust, ridges, and sharp edges of scores, the journals should be lapped with an oilstone or with an oilstone powder. Carborundum can be used if care is taken to remove all particles after lapping. g. Bearing Adjustments. Bearing adjustments consist mainly of alinement, fitting, and grooving; however, these adjustments must be carefully and correctly made or serious operating troubles can result. Trouble in alinement of shafting and bearings can be due to faulty shop work. When shafting is performed in the shop, special care should be taken to see that coupling faces are perpendicular to the shaft axis, and the peripheries of matching couplings are exactly concentric. These surfaces are indispensable in verifying the alinement of shafting and bearings aboard the vessel. h. Fitting Bearings. Bearings are usually finish-bored to a diameter equal to that of the journal and the oil clearance, and little or no fitting should be necessary. Where hand-fitting is required, a mandrel should be used; the mandrel should have a diameter equal to that of the journal and the oil clearance. The first step in hand-fitting is to coat the mandrel with a compound such as Prussian blue. One half of the bearing is placed on the mandrel and turned slightly to cause the coloring on the mandrel to adhere to the high spots on the bearing. These high spots should be removed with a scraper and the fitting operation repeated until the coloring matter is uniformly distributed over the bearing surface. This indicates that all of the bearing surface is in contact with the journal. When no mandrel is used, contact with the journal should be limited to a small area of about 30 degrees in the bottom of the bearing. Care must be taken in scraping a bearing to see that the lining is kept concentric with the shell and to avoid taper runout. In starting a new bearing, follow instructions given in a above. i. Liners-Shaft. Liners or shims are generally used to permit ready adjustments of bearing clearances within small limits. Such liners are generally copper or brass. Tinned sheet iron or plate should never be used. Liners should be held in place by dowels and should be designed so they are readily removable without drawing the bolts. Liners are never used in turbine or reduction-gear bearings. j. Taking Leads. One method used in measuring the clearance of a bearing is called taking a lead and is accomplished as follows. (1) Remove upper half of bearing. (2) Lay several lengths of soft unalloyed lead wire around journal. Do not use solder wire of any type. Do not use a large diameter wire to measure a small clearance, as it can deflect the cap and give a false reading. (3) Replace upper half of bearing and set it up on all bearing nuts. Mark position of each one. (4) Remove top half of bearing; examine and caliper leads. k. Placing Leads on Journal. A method of placing leads on the journal is shown in figure 187. Leads that are heavier than required for the clearance to be measured should not be used. When taking leads, care should be used so that all bolts, boltholes, bearing surfaces, liners (if used), and butting faces of the shells are free from foreign matter. When the leads have been properly placed and the bearing assembled, the nuts should be run down to bring the shells solidly against the liners or bring them metal to metal of butting faces if no liners are used. After this has been accomplished, no more force should be applied to the nuts, as it could result in deforming the threads of straining the metal of the bolts. When set up, the position of the bearing nuts should be marked so they can be retightened the same amount after the loads have been removed. l. Marking Bearing Nuts. One method of marking bearing nuts is to graduate the nut Figure 187. Placing leads on journal. AGO 6244A collar, numbering each graduation. In selecting the number of graduations to use, the number of threads to the inch on the bolt should be considered. m. Examination and Measurement of Leads. When the leads are removed from the journal, one end of each lead should be pinned to a piece of paper with the leads spaced the same distance apart and arranged in the same order as they were on the journal. If, upon examina~ tion, the wire is found to be squeezed out evenly along its entire length, the clearance is uniform. If the leads are squeezed wide and thin in some places and narrow and thick in others, the clearance is irregular. The thickness of each lead should be carefully measured with a micrometer at several places along the length of the wire so that the amount of clearance at all points is known. Leads which vary in thickness indicate an uneven bearing surface. Such bearings should be refitted to give a uniform clearance. n. Bearing and Shaft Clearance Tables. To assist in inspection and replacement of shaft bearing clearances, use tables XV through XVIII as a guide in the absence of other instructions. Table XV. Stern Tube and Strut Water-Lubricated Bearing Clearances A B c Minimum operating clearance of Total clearance Diameter of journal (inches) bearings (see note 2) (inches) at which bearing should be renewed (inches) 1 0.015 0.070 Ph 0.016 0.081 2 0.017 0.091 2% 0.018 0.100 3 0.020 0.107 4 0.022 0.120 5 0.025 0.131 6 0.027 0.142 7 0.030 0.153 8 0.032 0.164 9 0.035 0.175 10 0.037 0.185 11 0.040 0.196 12 0.042 0.206 13 0.045 0.216 14 0.047 0.226 15 0.050 0.235 16 0.052 0.244 AGO 5244A Table XV. Stern Tube and Strut Water-Lubricated Bearing Clearances-Continued A B c Minimum operatingDiameter of clearance of Total clearance journal (inches) bearings at which bearing (see note 2) should be renewed (inches) (inches) 17 0.055 0.253 18 0.057 0.261 19 0.060 0.269 20 0.062 0.275 21 0.065 0.281 22 0.067 0.286 23 0.070 0.290 24 0.072 0.294 25 0.075 0.297 26 0.077 0.300 27 0.080 0.303 28 0.082 0.306 Note I. The vessel's plans should be referred to, in every case, prior to renewal of bearings. Note 2. The values given above under column B are minimum operating bearing clearances for all types of sliding contact bearings, after dimensional changes due to swelling or deflection of the wearing material have taken place. Swe1ling characteristics of phenolic resin and lignum vitae bearing and deflection characteristies of natural or synthetic rubber-faced bearing are such that the following additional allowances must be made, at time of instaUation of wearing material, to correct for swelling and deflection characteristics as follows: a. For phenolic resin bearings installed dry with cotton fiber laminations perpendicular to shaft axis, allow 1 percent of wearing material thickness for swelling. b. For phenolic resin and lignum vitae bearings installed wet after soaking for at least 6 months). no allowance for swelling will be necessary, as swelling due to water absorption will have practically ceased. c. For natural or synthetic rubber-faced bearings, no allowance for deflection by installing activity wiU be ·necessary, as wearing material is manufactured to final design dimensions which will provide proper minimum clearances. Table XVI. Centrifugal Pump Shaft Bearing Clearances (White Metal) Journal Bore of bearing Minimum Wear at Diameter (inches) Tolerance (inches) clearance-, journal and bearing (inches) Tolerance (inches) which bearing should be renewed (inches) 1 +0.000 0.025 +0.001 0.0075 -0.001 =0.000 2 +0.000 0.003 +0.001 0.0075 -0.001 -0.000 3 +0.000 0.004 +0.001 0.010 -0.001 -0.000 4 +0.000 0.005 +0.001 0.015 -0.001 -0.000 Note. Allowable wear indicated as approximate only and is based on average wear ring clearances. Table XVII. Line Shaft Spring Bearing Clearances Table XVIII. Oil Clearances for Turbine, Reduction Gear, Generator and Motor Bearings Clearance at ' Journal diameter (inches) 1 Minimum clearance (inches) 0.007 Maximum clearance (inches) 0.009 which bearing should be rebabbitted (inches) 0.017 Basic diameter of journal (inches) Minimum oil clearance when rebabbitting bearings (inches) Maximum oil clearance when rebabbit ing bearings (inches) Maximum oil clearance at which bearing should be rebabbitted (inches) 2 3 4 5 6 7 8 9 10 11 12 13 14 15 .16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 0.007 0.007 0.007 0.008 0.010 0.011 0.012 0.013 O.D15 0.016 0.017 O.D18 0.020 0.021 0.022 0.023 0.024 0.025 0.027 0.028 0.029 0.030 0.031 0.032 0.033 0.034 0.035 0.036 0.037 0.009 0.009 0.009 0.010 0.012 0.013 0.014 0.015 0.018 0.019 0.020 0.021 0.023 0.025 0.026 0.027 0.028 0.029 0.032 0.033 0.034 0.035 0.037 0.038 0.039 0.041 0.042 0.043 0.045 0.017 0.017 0.017 0.019 0.022 0.025 0.028 0.030 0.033 0.036 0.038 0.040 0.042 0.044 0.046 0.047 0.049 0.051 0.052 0.054 0.055 0.056 0.058 0.059 0.060 0.061 0.062 0.063 0.064 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 0.005 0.005 0.005 0.006 0.007 0.008 0.009 0.010 0.011 0.012 0.012 0.013 0.013 0.014 0.015 0.016 O.D17 0.018 0.019 0.020 0.021 0.022 0.023 0.024 0.025 0.026 0.027 0.028 0.029 0.007 0.007 0.007 0.008 0.009 0.010 0.001 0.012 0.013 0.014 O.D15 0.016 O.Dl7 O.Dl8 0.019 0.020 0.021 0.022 0.023 0.024 0.026 0.027 0.028 0.029 0.030 0.031 0.032 0.033 0.034 0.015 O.D15 0.015 0.015 0.015 O.D18 0.021 0.024 0.027 0.030 0.033 0.036 0.039 0.042 0.045 0.045 0.045 0.045 0.045 0.045 0.045 0,045 0.046 0.048 0.050 0.052 0.054 0.056 0.058 30 0.030 0.035 0.060 Note. The above figures represent the minimum acceptable clear ance at any point in a bearing. Section Ill. CONTROL OF ELECTROLYSIS 217. General Electrolytic corrosion, in general, is discussed in chapter 5. Chapter 3 outlines the prevention of electrolytic corrosion to stored floating vessels and amphibians. This section describes methods used and replacement of wasting plates, their location, and installation. 218. Methods Used Two ways to prevent electrolysis is to provide wasting plates and to maintain an equal and like change on all metal parts in contact with the water. Zinc is used for wasting plates, which are also called zinc protectors or zinc electrodes. Zinc, except for magnesium and its alloys, is more easily stripped away by an electric current than other metals and, in a good conducting bond with other metals, will protect those metals by sacrificing itself. Another method of controlling electrolytic corrosion is to electrically connect all metal parts on the hull, which eliminates the possibility of having changes of different voltages or opposite polarity on different metal parts. 219. Replacement of Wasting Plates Zinc protectors should be replaced when they become wasted away to the point that they fail AGO 6244A to provide adequate mass r.nd surface area. They should also be replaced or reattached if loose. Zinc protectors for installation and replacement will conform to types ZHS or ZSS of Military Specification MIL--A-18001. Type ZHS will be used for large vessels and type ZSS will be used for small vessels. Type ZHS measures 1%, by 6 by 12 inches, weighs approximately 23.5 pounds, and has cast-in steel straps with protruding ends for attachment. Type ZSS measures 11,4 by 3 by 12 inches, weighs approximately 11.8 pounds, and has cast-in steel straps with protruding ends for attachment. 220. Location and Installation Zinc protectors will be located in the immediate vicinity of the propellers and will be symmetrically distributed. The distance between any two zinc protectors will not be less than 2 . feet. On wooden hull vessels, zinc protectors will be attached to the underwater surfaces of metallic structures and appendages to inhibit the galvanic corrosion of steel and removal of zinc from the bronze. Zinc protectors, conforming to Military Specification MIL--A-18001 and cut to size, will be attached to the interior of sea chests. For determining the quantity of zinc protectors of type ZHS or four protectors of type ZSS are needed to protect 400 square feet of freshly painted steel, 200 square feet of steel with a 1-year old coa;t of paint, or 100 square feet of bare steel. During installation, zinc protectors will be bedded in zinc oxide paste to the bare metal conforming to Federal Specification TT-P-463, type II, grade B. The edge swill be calked and the outside zinc surface will be kept free of paint. Where thickness of hull plating permits, cast steel straps will be welded on to provide better electrical connection between zinc and hull or other structure. Galvanized coat will be removed from steel straps prior to welding. Straps, but not zinc protectors, will be painted, after attachment, with the paint specified for underwater hull surfaces in chapter 16. When double plates are installed for attachment of zinc protectors, they will be left bare directly under protectors but painted the same as the adjacent hull on ex posed areas. AGO 6244A CHAPTER 10 MACHINERY FOUNDATIONS Section I. INTRODUCTION and torque of the machinery. In addition to 221. General bearing the weight of the machinery, boilerMacllinery foundations described in this seatings also prevent the shifting and topplingchapter pertain to those applicable to main over of the boiler when the vessel is in motion. engines and auxiliaries in the motor and enIn the case of propelling machinery, the moveginerooms. ments can become extreme, thereby subjecting 222. Purpose the seatings to taking up the forces and move The purpose of machinery foundations, or ment, thus preventing destruction of the maengine and boiler seatings, is to bear the weight chinery. Section II. MAIN ENGINES FOUNDATION 223. Description 224. Repair of Engine Bedplate The bedplate (fig. 190) is the backbone of The main engine foundation or bed is so conthe engine. It supports the entire weight of the structed that it becomes an integral part of the engine and receives tensile stresses which arevessel's hull and will absorb most of the forces transmitted to the foundation. In modern enand movement of the engine. The weight of an gines, the bedplate housing rests directly onengine can be supported by solid floors, which the engine foundation. The vessel frames are are normally provided with lightening holes to constructed with a recess which enables the ,,, lessen the weight of the structure. The main upper half of the main bearing to be removed engine seatings must be capable of taking up while the lower half remains held in a cradle, the inertial resistance caused by the rolling or bedplate, which is bolted to the engine's movement of a vessel. In a reciprocating en transverse framing. Tie rods are also used to gine, the rolling movement of the vessel will aid in firmly securing the bedplate. The upper cause tension in one crosshead guide plate and half of the main bearing is held in position by compression in the other. To take up these jack screws. Some important measures to be tensile and compressive forces, extra longitu'considered when installing the bedplate are as dinal strengthening is provided in the double follows: bottom by intercostal plating. The thickness of a. Insure that all bedplate surfaces coming this intercostal plating varies proportionately into contact with engine foundation have been with the size of the vessel in which it is used. machined to a true surface. Figure 188 shows a typical engine mounting b. Insure that body-bound type bolts are usedwith stiffeners and reverse frame. In steel for securing bedplate. hulls, the main engine is secured to the reverse frame by one of two methods: the engine mount Note. In some engines, the body-bound bolts are uesd only in the center of the bedplate, about four on is welded in place or bolted with rubber each side, to hold the engine in correct alignment. washers and bearings (fig. 189). The remaining bolts are not the body-bound type but AGO 5244A REVERSE FRAME SIDE INTERCOSTAL KEELSON Figure 188. Typical engine mounting with stiffeners .and reverse frame. RUBBER BEARING Figure 189. Bolt with rubber washer and bearing fm· securing engine mount. are holddown bolts which permit fore-and-aft expansion of the bedplate. Caution: Because of the natural vibration in all reciprocating engines, it is necessary that the holddown bolts be firmly secured. The slightest weaving of the engine will result in overstressing and continued running will undoubtedly loosen the holddown bolts. c. Check body-bound bolts periodically to insure tightness. d. Correct excessive clearance by reaming holes and installing oversized body-bound bolts. Caution. Any variation from correct alinement could result in cracking the bedplate or bearing supports. 225. Repair of Mounting Rails Mounting rails are part of the engine bedplate and secure the engine to the engine bed with hanger bolts (fig. 191). Before the mounting rails are installed, they must be machined to the exaot thickness to prevent twisting the bedplate and misalinement of the engine and propeller. Misalinement of the engine and propeller will cause vibration and damage to the struts, engine, and other equipment. If vibration does occur, the point of vibration should be determined and corrected by placing shims or a vibration damper under the mounting rail. a. Vibration. There is no such thing as a vibrationless engine. After a diesel engine is balanced as fully as its construction permits, it will still cause a certain amount of vibration while operating. In order to absorb the vibration, the engine must be provided with dampers which prevent damage to the engine or its mount. There are two general types of vibration dampers in use on harbor craft: the engine vibration damper and the engine mount vibration damper. (1) The engine vibmtion damper is in the form of an extra flywheel connected to the front end of the crankshaft as shown in figure 192. This reduces the crankshaft stresses to a point where the engine can be safely operated at increased speeds. Th~ damper as- AGO 5244A Figure 190. Typical bedplate. sembly is made up of rubber blocks bonded together with a metal ring on one side and a stamped metal disk on the other. The light and heavy dampers are bolted and doweled together and secured to the driving hub. The hub is positioned by a tapered inner and outer cone. Endwise movement of the assembly on the crankshaft is prevented by a front end pulley forced firmly against the outer cone by a retaining screw in the end of the crankshaft. (2) The engine mount vibration damper consists essentially of a flexible engine support made of rubber, cork, or metal springs. The damper will allow a small deflection of the engine in any direction and absorb the vibration before it is transmitted to the foundation. However, the fitted pins in this type damper restrict its usefulness to absorption of only those vibrations due to vertical shaking, pitching, and rocking. b. Maintenance of Vibration Dampers. Vibration dampers are rigidly constructed and give very little trouble if properly maintained. Fuel oil and lubrication oil, as well as heat, are destructive to rubber, and the damper should be protected against these agents. Inspection should be made after overhaul to ascertain that the dampers turn evenly in a single plane without wobbling. Wobbling can be caused by the presence of dirt on the tapered surfaces of the cone. These surfaces must be kept clean at all times. AGO 5244A ADJUSTMENT BOLT Figure 191. Typical engine mounting rail. 226. Use of Engine Bed Shims Engine bed shims are normally used in wooden engine beds as a stiffener between the engine bed and the bedplate (fig. 191). They are made in sizes from 0.010 inch to 0.500 inch. The smaller shims are used to aline the engine and propeller shaft to prevent excessive vibration or breakage of the bedplate. Very little maintenance is required on engine bed shims. Normally, they should not be used more than once, as vibration with steady running of the engine will score or dent the shims. Shims can be used more than once only if they can be machined down to uniform thickness. 227. Cleaning of Engine Mounting a. Engine mounts should be kept free from oil and grease and cleaned as often as possible. Caution: Fuel oil will cause deterioration in rubber vibration dampers. b. Rust, caused by salt water, should be chipped off and the metal cleaned. c. A coat, 1 millimeter thick, of zincchromate should be applied. d. The engine mounts should be painted to match the rest of the engine. SPRING VIBRATION DAMPER RUBBER VIBRATION DAMPER Figure 192. Typical engine vibration dampers. e. The bottom of the engine bedplate should be cleaned and coated with bituminous emulsion, 5 to 6 millimeters thick. Caution: Bituminous emulsion should be applied only by qualified personnel. 228. Replacement of Components No components should be replaced in the engine bed or mounting rails except by fully qualified personnel. This is required because each time a part is removed or replaced the engine can be put out of alinement, causing vibration or the bedplate and mounting rails to break. If the engine is pried up, the shims and seating· of the mounting rails can become damaged. This will cause excessive vibration at high speeds and misalinement of the engine. When replacing any components of the mounting rail or engine bedplate, the engine should be either jacked up or lifted by overhead tackle to prevent damaging the machined surfaces. Section Ill. AUXILIARY EQUIPMENT mounted and dismounted. This construction 229. General should also enable the connecting bolts, whichThe motor and enginerooms contain a large have to be as close to the stiffeners as possible,number of auxiliaries, among which are diesel to be properly handled. The seatings are norand turbo dynamos, distilling apparatus, mally welded and machined prior to being inpumps, filters, donkey-boilers, and condensers. stalled on the vessel. Some of these auxiliaries are mounted on beams or platforms (fig. 193) fitted to the bulk 230. Repair or Replacement of Components head or frames. Most of these auxiliaries are erected on the deck plates or at the vessel's Because all auxiliaries are mounted on deck side. The seating for this machinery should be platforms or bulkheads with bolts, repair and strong, have little weight, and be readily acmaintenance are simpler if the equipment is cessible for inspection and repairs. These seatmoved. Figure 194 shows a typical bulkhead ings should be constructed so that the auxiliand overhead mounting for auxiliaries. All aries to be erected on them can be easily mounts must be machined on top for a close fit BULKHEAD -----.."-!1 CAST STEEL BEARER WATER SPACE FITTED BOLT CAST STEEL FLOOR ~0 0 I WELDED BEARER BOILER SHELL DOUBLE BOTTOMDOUBLE ANGLE Figure 193. Deck platform and mounts for auxiliaries in the engineroom. AGO 5244A 254 and to prevent vibration during operation of the auxiliaries. In moving or raising an auxiliary, a jack or overhead tackle should always be used. ~ a. Boiler Seatings. Boiler seatings prevent the boilers from shifting when the vessel is rolling or pitching in heavy seas. The boilers are arranged in the lowest possible part of the vessel and in some cases only a few inches off the bottom of the bilge. The seatings are made up of heavy steel plating at the bottom of the boiler. The boiler seatings are ~__constructed aboard the vessel and welded in place. The boilers are then set in the seatings and bolted in place through the flanges hliilt on the boilers. Sizes of the bolts are determined by the sizes of the boilers and the functions they are to perform. Boiler seatings should be inspected regularly for loose nuts oF-bolts and tightened as nec~ssary. Inspect the_seating of -· ·-VERTICAL FLANGE OF ANGLE WELDED TO STIFF EN ER ·-- ; ;:::.::::--"/-~\ MOUNTING 1( d(_ II • WELD. \.~--"/\~//II -.__ ~=-_:;::J ~.,;_-~ BULKHEAD STIFFENERS Figure 194. Typical bulkhead and overhead mounting for auxiliaries. AGO 5244A the boiler for rust spots. When rust is found, it should be removed to the bare metal by chipping or wire brushing and repainted. b. Pump Seatings. Pump seatings can be placed on the deck floor or on the bulkhead. Pump seatings are built and welded in place before the pumps are installed. Usually, the part of the seating which will hold the motor for driving the pump is reinforced to prevent vibration. If, after the pump and motor have been installed, vibration is excessive, mounting dampers may have to be installed. The motor and pump will be secured to the seating with bolts and nuts. This is for easy access to repair or for removal. c. Generator Seatings. Generator seatings are located on the main deck of the engine room and are constructed of very heavy metal. The seating is built and welded in place to fit the generator bed, as this type of machinery weighs from 1 to 5 tons and must be assembled in place. After the engine bed has been set in the seating, the generator must be checked for vibration. If vibration exists, vibration dampers should be installed. Maintenance of generator seatings should be performed as follows: (1) Inspect for loose nuts and bolts. If found loose, check for excessive wear and replace defective bolts and nuts, (2) Check for rust on seating, and clean and repaint as necessary. (3) Check wire connections for loose or worn wiring, and repair or replace as needed. Caution: Do not try to move generator or other machinery with a pry bar, as this will break or damage flanges. Use jack or overhead tackle. 231. Cleaning and Preservation a. Auxiliaries and mounts should be kept free of grease and oil at all times. An accumulation of grease and oil makes it impossible for maintenance personnel to perform inspections adequately. This could result in a broken mount or loosened mounting bolts going undetected and thus in major damage to the equipment. b. When an auxiliary is removed for repair, d. If a painted foundation for a mount starts the mount should be cleaned and a thin coat of to peel, the old paint should be stripped to bare oil spread on the surfaces. metal, the surface cleaned thoroughly, and a coat of zinc-chromate primer applied. When c. Machined surfaces should never be painted, this primer has dried, paint the foundation to as this will adversely affect balancing of the machinery when the machinery is reinstalled. match the attached machinery. AGO liU4A CHAPTER 11 WATERTIGHT INTEGRITY Section I. TESTS 232. General Watertight integrity is the ability of those parts of the vessel that are designed to prevent the passage of water to maintain watertightness. Watertightness is required of shell plating, boundaries to water tanks and structures, and closures of compartment fittings which could be required to restrain flooding. Periodic inspection of watertight boundaries is imperative, and care should be exercised in making and reporting these tests and inspections. In order to insure the control of hull damage, required standards of tightness should be determined, and specific tests and inspections must be made. 233. Standards of Watertightness When any flooding occurs, watevtight subdivision above and below the waterline operates beneficially to minimize loss of buoyancy, loss of stability, and to conserve main propulsion, vessel control, and fire control. The hull repairman is charged with the responsibility of insuring that compartments originally waterproof will remain waterproof. Visual inspections and water pressure tests will aid the repairman in determining if repairs are necessary to retain watertight integrity. When corrective work has been accomplished on a vessel compartment, appropriate entries should be made in the repair record book. These entries should include the tests and inspection both before and after completion of the corrective work. The standards of watertightness are normally classified as outlined in a below. a. Test Requirements. During inspection of the vessel, the condition of certain compartments will indicate the necessity to perform detailed tests to maintain watertight integrity. AND INSPECTIONS All vessels having watertight and airtight compartments should have a Schedule of Watertight Integrity Tests and Inspections. This schedule enumerates all compartments on the vessel that are to be tested or inspected, the type of test or inspection to be conducted, and the period or frequency of such test or inspection. Allowable limits are also noted on this schedule. The type of test depends upon the classification of a compartment, its bounding area, temperature conditions, and the number, size, and location of fittings such as doors, manholes, stuffing boxes, and other openings. b. Correction of Defects. (1) No corrective action need be taken when a compartment is determined as watertight. (2) A compartment determined as unsatisfactory deserves an immediate detailed inspection, and corrective action should not be postponed or delayed. This could be a relatively minor repair, such as replacing a gasket around a compartment door, tightening a drop bolt, or lubricating a hinge bolt, or a major repair or replacement. 234. Maintaining Tightness-Methods Watertight integrity is of the utmost importance to the safety of the vessel. Routine visual and operational inspections of all boundaries and fittings are made by personnel assigned to the vessel in addition to the periodic surveys or inspections conducted by the U.S. Coast Guard and the American Bureau of Shipping. These tests and inspections will be in accordance with latest approved methods and will be conducted on all vessels in active service AGO 5244A to insure the proper maintenance of watertight integrity. Condition of the hull and the structural members is by visual inspection. When thickness of metal cannot be determined, a drill test or audio (sound) test will be made. a. Leakage Inspection. External boundaries of tanks containing oil or water should be inspected for leaks at least once in each annual inspection period. These inspections can be made in conjunction with the regular inspection of compartments. When making this leakage inspection, particular care should be exercised to note evidence of leakage that.can occur only when the tank is filled to capacity. b. Visual Inspection. ( 1) Periodic visual inspection should be made at least once in each annual inspection period. This visual inspection should be made where practicable by darkening one of the compartments separated by the boundary and lighting the other. Inspection of the compartment from the darkened side will disclose any defects that allow a diffusion of light. A checkoff list of fittings should be maintained by the commanding officer. All fittings, such as doors, hatches, manholes, deckdrain valves, voice tube c:;overs, and ventilation-duct covers, 'Should be carefully examined in conjunction with the boundary inspection and the condition noted in the checkoff list. Any defects discovered in boundaries should be cause for the compartment to be classified as unsatisfactory and considered as an urgent repair. (2) The periodic visual inspection generally involves some of the most important watertightness boundaries of the v,essel. Such compartments are the boilerroom, enginerooms, main motor rooms, and similar machinery spaces, as well as chain lockers, main battery handling rooms, uptake inclosures, and similar spaces. The periodic visual inspection should be made as carefully as possible, and successive inspections of a boundary should be made by different inspectors. c. Method of Making Water Pressure Test. The water pressure test is a method of determining the degree of watertightness by spraying water from a hose at a minimum of 30 psi. The water spray is directed against closures classified as watertight. Each compartment or closure classified as watertight will be tested at least once between the annual inspections. Prior to starting a water pressure test of compartment, the following steps will be taken: ( 1) Perform a visual inspection to ascertain that all openings are closed and that no discernible defect exists. (2) Effect these closures by securing watertight doors, hatches, vent covers, and other closure devices in the normal manner. If special measures are needed to make a closure, such as hammering down the dogs with a mallet, or using special gaskets or wooden plugs, repairs should be made before completion of the test and proper notation made in the repair log. (3) Test compartments which are pierced by rotating shafts or other moving parts, such as shaft alleys, when such machinery is not in operation. ( 4) Determine the location of defects by giving attention to the known condition of adjoining compartment bulkheads and decks, as determined from previous inspections. ( 5) Restore openings in the compartment to their normal operating condition upon completion of the tests. Section II. BULKHEADS AND HATCHES 235. Bulkhead Openings-General which they are installed. Doors can be distinguished as follows: Bulkhead doors are closures for bulkhead access openings. They are constructed so that they a. Watertight Doors. Among the s,trongest will be structurally strong as the bulkheads in doors are those classified as watertight doors. AGO 6244A ·258 They are designed to resist 1% times a.S much pressure as the bulkheads through which they give access and have from 6 to 12 dogs for securing them evenly and firmly. Some doors have dogs that must be individually closed and opened as shown in figure 195. Quick-acting watertight doors (fig. 196) have handwheels which operate all dogs simultaneously. Gaskets are used as seals between door and frame. Gaskets should never be painted and must be kept free of dirt and grease. When replacing a gasket, the steel surface under the old gasket should be carefully cleaned. When installing new strip gasket material, plan to have only one break or joint, cutting the material so the two butts will fit snugly. A simple way to test the knife edge and gasket is to chalk the bearing surface of the knife edge and then close the door by the usual method. Irregularities or breaks in the chalk line indicate improper adjustment of the dogs, a defective gasket, warping of the closure, or worn places along the knife edge. Some minor repairs to correct these irregularities are the following: (1) Knife edges should be kept bright, smooth, and free of dust, grease, and paint; beeswax can be used for this purpose. (2) Clean knife edge contact surface with abrasive cloth. ( 3) If knife edge does not bear evenly against gasket, build up behind gasket Figu.re 195. Watertight door with individually operated dogs. AGO 5244A procedures. To close, first set up a dog that is opposite the hinges, with just enough pressure to keep door shut. Then set up two dogs snugly on the hinge side, after which all the remaining dogs can be set up evenly to insure an even bearing all around. When opening a closure, start with the dogs nearest the hinges. This will keep the door from springing, thus making it easier to operate the remaining dogs. b. Airtight Doors. Airtight doors are designed to be fumetight and gastight. When such doors are used in air locks, they usually have lever-type, quick-acting closures, but some can have individually operated dogs. The. maintenance and repair on airtight doors adheres generally to the procedures listed in a above, relating to watertight doors. c. Nonwatertight Doors. Nonwatertight doors are made of light steel or sheet metal and are used in nonwatertight bulkheads; therefore, they need inspection for proper operation. d. Panel Doors. Panel doors are ordinary joiner doors which are made of metal. They are used to provide privacy closures for staterooms, wardrooms, and the like. All doors to privacy closures used by personnel will be equipped with emergency kick-out panels as required by U.S. Coast Guard regulations. The kick-out panels provide a means of escape during emergencies when the door cannot be opened due to damage. These doors are also considered as Figure 196. Quick-acting watertight door. nonwatertight and no special testing is necessary. by using wood or metal shims or cardboard if knife edge is unevenly worn 236. Hatches-General or has corroded, the only satisfactory Hatches are horizontal doors used for access·repair is to build up the knife edge through decks and should always maintainwith welding and then dress down the watertight integrity. A hatch is fabricated ofbuilt-up surface. either wood or steel and can be set with the (4) Dogs and pins can be removed for top surface flush with the deck or can be set cleaning, adjustment, and repair. All on a coaming. Access hatches and carg~atches cotter pins and lock nuts should be differ greatly and are discussed separately. checked. Never try to cle;m threads of a. Access Hatches. Access hatches can bedog bolts with files, emery cloth, or either the quick-acting operated type (fig. 197)sandpaper. Steel bolts will not rust if or those secured with individually operated they are kept clean and given a light dogs. Access hatches serve to allow access tocoating of grease occasionally. certain areas such as water and fuel tanks and ( 5) To prevent warping of the closure, voids. These access closures depend for their use the proper closing and opening tightness upon a rubber gasket mounted in the 260 AGO 52UA covering part to ~close against a fixed position hatches are generally .the same as outlined in knife edge. These gaskets are either pressed paragraph 235a for watertight doors. into a groove or secured with retaining strips held in place with screws or bolts. These hatches are subjected to constant weather abuse and water from deck cleaning; therefore, they must be watertight at all times to have watertight integrity. These hatches are seldom used as purely an entrance or exit point for personnel, although an escape scuttle is incorporated into some hatches. When replacing the rubber gasket on these hatches, be sure that the proper replacement gasket is available. In emergency cases, it could be necessary to continue using the old gasket by placing shims under it to make it flush against the knife edge. Minor repairs and maintenanCe practices for access Figure 197. Typical bolted access hatch with escape scuttle. b. Cargo Hatch Covers. All cargo hatchways are provided with covers, either wooden or steel. Wooden hatch covers have the disadvantages of being liable to damage in a heavy seaway, being subject to catching fire, and allow ing a hold fire to spread over the vessel, plus having a high cost of maintenance because of the frequent removal and replacement of the hatch cover. The wood hatch cover is generally made of highgrade white pine with the ends encircled with steel bands. A waterproof tarpaulin is placed over the hatch cover when it is properly seated on the coaming. The hatch cover and tarpaulin are then battened down with steel straps, making it as watertight as possible. In the case of steel hatch covers, a gasket normally is positioned into a groove of the hatch cover, providing a watertight fit when it is cinched down with dogs or attaching lugs. In most cases, a tarpaulin is also placed over the metal hatch covers to further the watertight integrity of the vessel. c. Access Plates. Access plates are bolted to the plating of the deck, bulkhead, or coaming surrounding the hole. A gasket is used to provide a tight fit. In order to obtain a tight joint after a bolted access plate has been opened, the gasket must be replaced and renewed if in poor condition. The mounting bolts must be set up tightly and evenly all around. An ungasketed or loosely fitting access plate is not watertight and is a source of possible progressive flooding. Section Ill. AIR PORTS, PORTLIGHTS AND SKYLIGHTS 237. Port Lights (Air Ports) Port lights, or air ports, are openings in the sides or decks of a vessel, usually round in shape, and are nonopening or fitted with a hinged frame in which a thick glass is secured. The purposes of the port light are to provide light, ventilation, and vision from the interior of the vessel. Nonopening port lights provide light and vision only and must be watertight. In some instances, port lights are provided with an additional solid metal hinged cover, called deadlight, to afford protection should the glass be damaged and to prevent showing light from within. AGO 62UA a. Installation-Port Lights. The installation of port lights must comply with the rules of the American Bureau of Shipping. Normal practice is to provide opening-type port lights in spaces that are not air conditioned, and nonopening port lights in air-conditioned spaces in the following manner: ( 1) No installations should be made in the shell plating below the uppermost strength deck. (2) Above the uppermost strength deck, installations are restricted to the following:· (a) In ballistic structure, only as specifically shown on the vessel plans. (b) One in each stateroom, cabin, and office; however, two can be installed if the total length of the external boundary of the space exceeds 10 feet. (c) In living and dining spaces, one should be used for each 8 linear feet of external boundary. b. Installatio~Port Light Covers. Metal covers are usually installed on the inside of the glass port for most fixed (nonopening) port lights except those located in pilothouses. In addition to the above" standard covers, fixed port lights installed in ballistic plating, including those in pilothouses, are provided with ballistic covers. These covers, which are fitted on the outside, are of the same weight and kind of plating as that in which the port light is installed. Ballistic covers located in pilothouses or conning stations are fitted with slots for vision. c. Maintenance. To maintain watertight integrity under various conditions, personnel should familiarize themselves with the types of port lights and deadlights installed so that the covers can be correctly placed and secured at any time. Particular attention should be given to proper securing of battle covers. When tightening the dogs on port light lens frames, special care should be taken to obtain an even bearing all around to prevent breaking the glass lens when the vessel is in a seaway or hit by a heavy sea. In hinging up port light covers and deadlights, care should be taken to bring the hinge pin of the covers all the way to the end of the hinge. This will prevent breakage of the hinge. A typical port light with its dogs and hinges is shown in figure 198. d. Lens Replacement. Heat-treated or laminated heat-treated glass is specified for lenses in port lights. Installations with the older, nonheat-treated glass and those with wire glass will be replaced with heat-treated or laminated heat-treated glass when breakage necessitates replacement. Heat-treated glass has good resistance to breakage, due to the manufacturing HINGE HINGE PIN GLASS PORT LIGHT COVER SECURING EYE FOR OPEN POSITION BULKHEAD FR~E Figure 198. Typical port light. process which allows it to flex about three times as much as regular plate glass. It will break, however, so care is required when mounting the glass to avoid chipping the edge. After an old lens has been removed, clean the threads of the frame and the retaining ring. A light coat of oil can be applied to the threads. When the new lens is inserted, imbed the edge in red lead putty. This will give a· tight fit when the retaining ring is secured, thus insuring watertight integrity. e. Special Purpose Lenses. Special purpose lenses are installed only upon authorization. There are several types of special purpose lenses. Nonicing windows and organic plastic glass are described below. (1) Nonicing windows. Nonicing windows are composed of a lamination of two pieces of heat-treated glass. A transparent metallic oxide film is applied to the inside surface of the glasslaminar that is exposed to the weather. The oxide film conducts electricity between two bus bars installed in the window. Warning: This type window should be deenergized during maintenance to prevent injury to personnel. AGO 6244A. (2) Organic plastic glass. For special glazing purposes where extreme resistance to breakage is required, organic plastic glass can be employed. The two different types used are polymerized methyl methacrylate and vinyl chloride-vinyl acetate copolymer. These are seldom used, however, because they are highly susceptible to scratching, thus losing optical clarity. These materials also have poor aging proper- TYPICAL HINGE DETAIL ties, especially in sunlight where deterioration is rapid. Because of these disadvantages, they are used in port lights only as an emergency measure. 238. Skylights A skylight is a wood or metal structure, having port lights in its top, and fitted over an opening in the deck to afford light and ventilation to the spaces below. The top covers are Figure 199. Typical skylight. AGO 5244A flat or pitched and are provided with hinges. lights are fitted with deadlights, while others They can usually be raised or lowered by a can be blacked out from the interior of the screw gear. Some port lights in the skylights vessel if such blackout condition is needed. are hinged and secured by the use of dogs, while Brass rods are frequently fitted over the glass others can be bolted to the skylight as a perfor protection. A typical skylight is shown in manent installation. Some port lights in sky-figure 199. AGO 6244A CHAPTER 12 SPARS AND RIGGING, AND BOAT DAVITS Section I. SPARS 239. Standing Rigging Standing rigging, made from galvanized, high-grade, plow steel wire rope, is used to support the masts. Standing rigging is in the form of shrouds, supporting the mast athwartships, or in the form of stays, supporting the mast in the fore-and-aft directions. Shrouds and stays are connected with turnbuckles equipped with locknuts. The effectiveness of shrouds and stays is reduced considerably if they are allowed to become slack. 240. Inspection of Standing Rigging Standing rigging should be inspected periodically and tightened as necessary in accordance with instructions in applicable technical manuals. A typical arrangement of shro.1ds and stays in shown in figure 200. 241. Adjustment of Standing Rigging The following procedures should be used when adjustment of standing rigging is necessary: a. Slacken all stays so that no unbalanced forces will be applied to mast. · b. Take up slack as uniformly as possible until sag is substantially eliminated from all stays and turnbuckles are handtight. c. Measure distance between ends of turnbuckle bolts. Tighten each turnbuckle so that it is shortened by using the formula, a distance equal to 1 inch for 60 feet of stay length, or by using a proportionate sum. 242. Worming, Parceling, and Serving In places where chafing is likely to occur, all metallic standing rigging should be wormed, AND RIGGING parceled, and served in way of splices and thimbles. Metallic standing rigging should be left bare elsewhere except for lubricant coating. Before serving, wire rope should be thoroughly clean and bright, free from rust, and given one coat of wire rope lubrication, Federal Specification VVL-L-751, and after parceling and serving, inclosed in canvas wrapping. Care sho11 1rl h~> t<>ken to insure that the lubrication is worked into the lays of the rope. Refer to Techmcal Bulletin TB 7 46-93-4. 243. Installation of Rigging Insulators Porcelain insulators or other approved insulators should be installed in metallic rigging TOPMAST STAY TURNBuCKLES. Figure 200. Typical arrangement of shrouds and .~tays. AGO 5244A STEP 1' WIND ON THE ANNEALED IRON SEIZING WIRE UNIFORMLY AND USE GOOD TENSION ON WIRE. UNLESS A SERVING MALLET is USED, THERE IS NO ADVANTAGE IN MAKING MORE THAN 10 WRAPS OF WIRE PER SEIZING. STEP 2 TWIST ENDS. WHEN WOUND AS IN 1, BE SURE TO TWIST WIRES COUNTERCLOCKWISE. STEP 3 GRASP ENDS WITH END CUTTING NIPPERS (DETACHABLE CUTTER TYPE) AND TWIST UP SLACK. DO NOT TRY TO TIGHTEN UP ON SEIZING BY TWISTING. SEE 4. STEP 4 DRAW UP ON SEIZING. STEP 5 TWIST UP SLACK, REPEATING OPERATIONS SHOWN IN 4 AND 5 IF NECESSARY. CUT ENDS AND POUND THEM DOWN ON THE ROPE. SEE 6. STEP 6 THE FINISHED SEIZING. Figure 201. Seizing wire rope prior to cutting. AGO 5244A in all surface vessels in which radio equipment i·s installed. One rigging insulator should be installed near the top of each member of standing rigging and Jacob's ladder, and the lower ends should be securely and effectively grounded. Each triatic stay or spring stay should be broken with insulators, one at each end, and the others spaced so that no section of the stay exceeds 10 feet in length. By breaking up the rigging in this manner, the heavy accumulation of static charges on wire ropes is prevented, and sparking, which might occur due to poor contact of long leads of wire rope with other metal, is reduced to a minimum. Rigging insulators should not be fitted to booms that handle heavy loads. Both ends of all uninsulated stays should be thoroughly and permanently grounded. The insulators should not be painted, tarred, varnished, or coated in any way but should always present clean surfaces. 244. Seizing Used Over Splices Iron wire seizing should be used over the splices which secure the insulators in the rig-. ging. The proper procedure for iron wire seizing, for purposes of cutting the wire rope, is shown in figure 201. The rigging should be parceled and served with marline at the splices only where corrosion usually begins. Seizing a completed eye splice is shown in figure 202. 245. Grounding Masts Unless otherwise directed, mast stays should be grounded at the deck to prevent accumulation of static charges. One method of grounding shrouds and stays is shown in figure 203. To avoid the formation of loops by the grounded masts stays and to reduce the volume of deviation of the radio direction finder, a rigging insulator is inserted in each mast stay neJ.r the top. This does not apply to vessels fitted with high frequency direction finding equipment. Rigging on these vessels should be broken by STRANDED GROUND WIRE---• l!'igure 202. Seizing an eye splice. Figure 203. Ground shrouds and stays. AGO 5244A METAL MAST BAND FITTING COPPER GROUND STRIP Figure 204. Grounding a wooden mast. Section II. 248. Description A boat davit is essentially a crane used to lower and raise such vessels as landing craft, lifeboats, whaleboats, and motor launches. Connected with the boat davits are four basic mechanisms which are necessary for the proper operation of the davit. These mechanisms consist of the boat davit winch, deck winch, standard release gear, and falls tensioning device. 249. Types There are several different types of boat davits. Some of the more common types of boat davits used on Army vessels are described as follows: a. Gravity Davit. A gravity davit depends upon the force of gravity to move a boat from the inboard launching position to the waterborne position. The entire launching or:eration insulators in such a manner that no undergrounded section of the rigging is longer than 15 feet and no grounded portion is over 8 feet in length. 246. Charring Prevention of Wood Masts and Spars !viost metal fittings on wooden masts and spars should be grounded by means of a copper strip at least 1 by Y:J 2 inch to prevent charring the mast. Figure 204 shows the grounding of metal fittings on a wooden mast. The co~wer ground strip is bonded to the nearest steel superstructure that is connected to the steel hull of the vessel. It a steel vessel has masts constructed entirely of steel, grounding of the mast is not necessary. 247. Grounding and Insulation of Rigging Grounding and insulation of rigging should be as shown on the hull plan or the blueprint for the individual vessel. Most electrical insulation and grounds on metallic standing rigging should be inspected periodically for deterioration at points of contact between dissimilar metals. When deterioration is evidenced, the connections should be thoroughly cleaned and new parceling and serving applied, as outlined in paragraph 242. BOAT DAVITS is controlled by the falls tensioning device. A typical gravity davit is shown in figure 205. The trackway davit is a typical example of a gravity davit. It consists of a set of arms mounted on rollers which run on inclined trackways mounted on the deck. Because of the incline of the trackways, gravity will enable the boat and arms to move down the trackway from the stowage position to the outboard position so that the boat can be lowered into the water. b. Mechanical Davit. A mechanical davit (fig. 206) depends upon an external force to move the boat outboard in preparation for launching. With a mechanical davit, outboard movement of the boat is not under control of the falls tensioning device. A mechanical davit with arms in cresent form is called a cresent davit. 268 AGO 5244A STOWAGE POSITION WOOD BUMPER LASHING FALLS TENSIONING DEVICE ---{--....:.>fl""'6<§~~ 1', I I I I I I / I ----~I WINCH r ---~~\ 1 I, I \I I II 1·1 I \\\ II !\'I, TRACKWAY ASSEMBLY \\ \\\ /' \i\ LAUNCHING POSITION ',-________ \~ Figure 205. Typical gravity davit. The arms are racked in and out by a sheet screw, which can be operated by hand crank or by power. The boat hoist can consist of manila rope which is. led to the gypsy head of a deck winch or of wire rope which is led to the drum of a special winch furnished with the davit. This type of davit handles a single boat from 26 to 30 feet in length and up to 13,500 pounds in weight. The crescent davit has superseded most mechanical davits of boom and quadrant type. c. Jladial or Swing Davit. Radial or swing davits (fig. 207) are nonmechanical davits which are located near the deck edge. These davits consist of a pair of vertical arms extending from a pedestal. The boat is stowed on the deck and inboard of the davits. To prepare for launching, it could be necessary to move the OUTBOARD POSITION Figure 206. Typical mechanical davit. AGO 6244A ARM FALLS STOWAGE POSITION POSITION OUTBOARD Figure 207. Typical radial or swing davit. boat to an outboard position by partially rotating the vertical arms. 250. Safety Precautions The most effective safety precaution is a vigorous program of preventive maintenance. Most damage is attributed to improperly maintained and operated equipment rather than to design deficiencies or personnel failure. Observe the following procedures to help insure the safe operation of the boat davit. a. Insure that all nonoperating personnel are clear of the area prior to any boat handling operation. b. Insure that qualified operators perform each operation. c. Do not turn on the winch electric motor when a boat is being lowered, unless the motor is used in the lowering operation. d. Keep number of personnel in the boat use lifelines. e. Insure that lifting hooks are properly secured before a boat is raised or lowered. f. Be alert for any possible malfunction. g. Stop winch motor by using master switch, when paying out empty falls under power. 251 . Safety Devices The most effective safety device is a properly maintained davit and winch installation. Marine hull repairmen must be thoroughly familiar with boat davit and winch operation to be qualified in performing the required maintenance. Boat davit installations are provided with a number of safety devices, most of which are interconnected with the winch motor control. The most common safety devices with their intended functions and certain inherent limitations are listed below: a. Painted Stripes. All trackway-type davits, whether single or multiple bank, should have stripes of contrasting color painted on the davit head and trackways as follows: when the davit heads are in a stowed position, paint those davits where the inboard positive stops or the solidly compressed position of the buffer springs is more than, equal to, or less than 8 inches from the inboard contact surface. Note. For pivoted-type davits, the stripes should be painted to coincide at the stowed position. b. Emergency Disconnect Switch. An emergency disconnect switch is connected between the motor and the motor controller in the winch motor supply leads. This switch is located at the winch operator's station and is used to turn off the motor to prevent two-blocking of the davit when some other control component fails to function properly. The most serious limitation of this switch is that the emergency must be recognized by the winch operator in time to permit his actuating the switch prior to an accident. c. Handcrank Interlock Switches. Control interlock switches are mounted on the winch and, in order to engage the handcrank, the switches should be opened. The function of these switches is to prevent inadvertent energization of the winch motor. The major limitation of these switches is that contactors in the control panel can be closed manually by uniformed maintenance personnel, thus energizing the motor. Warning: Power operation of winch during engagement of handcrank can be fatal to personnel operating the handcranks. d. Trackway Limit Switches. Control limit switches, located on each trackway of trackway-type davits, turn off the winch motor and prevent the davit arms from being driven into the positive stops. The primary limitation of these switches is that all personnel realize their 270 AGO 6244A relative inaccessibility. It is of utmost importance that trackway limit switches are intended to function as overtravel switches, not as stop switches. e. Hoist Limit Switches. Control limit switches, usually of the geared type, are installed on drum type winches and are used for hoisting the boats with mechanical davits. Hoist limit switches have the same purpose and limitations as trackway limit switches in that all personnel must realize that they are not intended to function as stop switches. f. Safety-Type Handcranks. Safety-type handcranks include a mechanism which permits overriding in the hoist direction of rotation. Safety-type handcranks function in such a a manner that, if the winch motor is energized while the winch is being manually cranked, no force is exerted on the crank handle from the winch side. Safety-type handcranks are limited to use on nonreversing winches and can be used in lieu of handcrank interlock switches. g. Brake Interlock Switch. The brake interlock switch is connected to the manual brake on reversing winches and functions to prevent energizing the motor in the payout direction when the brake is not released. This switch is intended primarily for protection of the winch gearing and should not be used as a stop switch is used. h. Double Break. The double break feature is the inclusion in the winch control panels of sufficient contactors arranged so that when the motor supply is interrupted by the controller, the supply leads are opened in two places by contactors, thus acting as a double break. 252. Maintenance Procedures Improperly maintained equipment is unsafe equipment. The following maintenance items should be performed by the hull repairmen and are listed to supplement those maintenance instructions contained in technical manuals for individual equipment: a. Inspect the davit installation weekly and operate winch as needed to make sure that all safety devices function properly. b. Pay particular attention during inspection to electrical components mounted in exposed AGO 5244A locations. Leakage of water into the inclosures of electrical components is one of the major causes of accidents. All seals, gaskets, and cover bolts should be in place and in good condition. All limit and interlock switches, not located in a position to be subjected to wash, should be provided with a %-inch drain hole in the lowest part of the housing to prevent an accumulation of moisture. c. Insure that all contactors in the control panel operate freely and are in good condition. This is particularly important where the control includes the double break feature (para 251h), as one contactor might stick and still give the appearance of normal operation. d. Check insulation resistance to grol'nd, particularly through external switches. e. Insure that gravity-type davit arms travel inboard together. Adjustment of the length of the boat falls could be required. f. Accomplish regular lubrication of mechanical components as outlined in applicable technical manuals. g. Check the winch manual brake for proper adjustment; insure that braking surfaces are free from rust and grease. h. Replace the wire rope falls during each ··-"~-. regular overhaul period and more frequently · if necessary. Replacement is considered necessary when a broken strand appears, when any of the outer strands appear to be worn to two thirds of their orginal diameters, or when the falls have been subjected to excessive strain due to kinking or sharp bends. The falls should be kept properly greased at all times. i. Note that other points requiring more regular inspection include the centrifugal brake, strongback trunnion bearings, and block latching mechanisms. j. Note also that welding repairs to the body or tumbler bearing surface of Raymond (diskbearing) hooks should not be undertaken by forces afloat except in extreme emergency. Hooks should be replaced when damaged. 253. Testing Davits Boat davits should be tested by the hull repairman after each new installation, after 271 major repairs, and annually. The test should ingly, test loads have been designated as fol be selected on a basis of davit design capacity. lows: Original label plates should not be changed (1) Test A. For old design handling landunder any conditions. For testing purposes, ing craft. davits can be divided into two groups: those (2) Test B. For new design davits handesigned for handling landing craft and those dling landing craft. designed for handling craft other than landing craft such as motor whaleboats, lifeboats, and (3) Test C. For davits handling craft motor launches. Required design capacities for other than landing craft. later landing craft handling davits have been b. Mechanical Davits. Mechanical davits willincreased so that each group can be further be tested in accordance with Test D of tabledivided, for test purposes, into old and new XXIX. design davit categories. Reference should be made to applicable technical manuals supportc. Radial Davits. Radial davits will be tested ing specific craft for rated line speeds and to in accordance with Test E of table XXIX. insure that the proper test is being applied. Reference should be made to aplicable technical a. Gravity Davits. Gravity davit tests will manuals supporting specific craft for rated line depend upon the design of the davit. Accord-speeds. To,ble XIX. Tests for Davits Test A Test B Test C Test D and Test E Hoisting Nomenclature of load and way handled (see note 1) Hoisting (pounds) Lowering (pounds) and Lowering (pounds) Hoisting Lowering Hoisting Lowering Working load (from 18,500 26,600 26,600 Working load Working load Hoisting Hoisting water to stowed (see note 2). (see note 2). weight weight position and return of boat. of boat. at rated speed). Dynamic load tween inboard (beand 21,500 39,900 39,900 150% of working load. 150% of working load. 150% of working load. 150% of working load. outboard positions at no specified speed). Dynamic load (verti 26,600 39,900 39,900 150% of work 150% of work 150% of work 150% of work cal lift only, at no ing load. ing load. ing load. ing loarl. specified speed) . Static load (davit 53,200 ----- 53,200 200% of work ------------ _200% of work arms outboard). ing load. ing load. NOTES: 1. Loads listed to be equally distributed between the boat falls for test purposes. 2. Working load is the davit capacity shown on the original label plate on the davit; under no conditions will the original label plates be changed. AGO 5244A CHAPTER 13 GROUND TACKLE Section I. 254. Uses Anchors are classified according to their use and location as follows: a. Bower Anchors. Bower anchors are carried on the bow, usually in hawsepipes. They are used primarily for holding the vessel against current and in wind. b. Stream Anchors. Stream anchors, which are approximately one-fourth the weight of the bower anchors, are used when anchoring in a current to avoid swinging. c. Stern Anchors. Stern anchors are carried on the stern to prevent swinging and on landing craft, to prevent broach on the beach and to assist in retracting from beaches. d. Kedge Anchors. Kedge anchors are used for kedging and warping. When used in kedging, the vessel is moved ahead by taking the kedge anchor out in a boat, letting it go, and hauling the vessel up to it. When this is done to change the heading of a vessel, as by hauling the stern around, the action is called warping. ANCHORS e. Special Purpose Anchors. Special purpose anchors are designed for specific functions other than securing or moving the vessel. A .FLUKE COMMERCIAL STOCKLESS ~ RING MARK 2 STOCKLESS FLUKE STANDARD STOCKLESS Figure 208. Typical mushroom anchor. Figure 209. Typical stockless anchors. AGO 5244A 273 LIGHTWEIGHT DANFORTH Figure 210. Typical lightweight-type anchors. typical example is the mushroom anchor used for securing buoys. 255. Types Four types of anchors normally used on Army vessels are as follows: a. Mushroom Anchors. Mushroom anchors (fig. 208) are mushroom shaped with a shank projecting from the center of the cupped side. They are used as special purpose anchors. b. Stockless Anchors. Stockless anchors of three designs are in use: the commercial stockless, standard stockless, and Mark 2 stockless (fig. 209). The main differences in these anchors are in the length of the flukes and the holding power. The Mark 2 stockless anchor has the greatest holding power and the longest flukes; the commercial stockless anchor has the poorest holding power and the shortest flukes. The main advantage of stockless anchors is ease of stowage. They are used chiefly as bower anchors but can also be used as stern, stream, and kedge anchors. Figure 211. Typical Navy-type stock anchor. c. Lightweight-type Anchors. Several lightweight-type anchor designs are in use: two cast steel designs with different shaped flukes (fig. 210) and several fabricated steel designs. Lightweight-type anchors have high holding power equivalent to standard stockless anchors of twice their weight. Lightweight-type anchors can be used as bower, stern, stream, or kedge anchors. d. Navy-Type Stock Anchors. These anchors (fig. 211), in sizes below 150 pounds, are used as small craft anchors. They are also used for kedging and anchoring on hard, rocky bottoms. A variation of this anchor, with only one fluke, is used as an ice anchor. Section II. ANCHOR CABLE (CHAIN) 256. Types chain have been used on Army vessels. The types normally used are as follows: Although the die-lock and high strength welded steel types of anchor chain are now a. Standard Die-Lock Anchor Chain. The considered standard,· numerous types of anchor standard die-lock anchor chain (fig. 212) is a AGO 6244A DETACHABLE LINK SWIVEL DETACHABLE LINK STANDARD OUTBOARD SWIVEL SHOT AND METHOD OF ASSEMBLING ANCHOR SHACKLE DETACHABLE LINK •~m m""A'"""'~"""'o ~""""'"""' r--''r-.~.-...'~ i ~'"c"'""""' ) ( ALTERNATE ARRANGEMENT OF OUTBOARD SWIVEL.. SHOT AND METHOD OF ASSEMBLING Figure 212. Makeup of die-lock anchor chain. forged alloy steel chain in which the stud, although split through the middle, is an integral part of the link. b. High Strength Die-Lock Anchor Chain. This is a forged, heat-treated, alloy steel chain which has the same length and width as standard die-lock anchor chain, with an enlarged section at the lock. The stud is an integral part of the link and, although split through the middle, resists kinking more than other chains. High strength die-lock anchor chain has a proof load equal to the breaking load of the standard die-lock chain. It is designed in sizes of %, 1, 11Js, 13/s, 1%, and 1% inches. c. Heavy Duty Die-Lock Anchor Chain. This is a forged, heat-treated, alloy steel chain similar in design to the high strength, die-lock anchor chain, except that the end sections are oval shaped at the point of cross section. It is designed in sizes of 2%, 3, and 3% inches. d. Welded Steel Anchor Chain. Welded steel anchor chain is cold formed and scarfed, thoroughly annealed before welding, and lap-fire welded, or it is hot formed, hot scarfed, and lap-fired. The length of the scarf is not less than twice the bar diameter and the lap is not less than one-fourth the bar diameter. All links are welded. e. High Strength Welded Steel Anchor Chain. High strength welded steel anchor chain is made by several methods. In one method, the chain is made up of alternate solid forged and welded links, the welded length being reforged after welding, which gives the appearance of all forged or all cast links. In another method, every other link is welded by hand. In a third method, all of the links are welded, and the studs are either welded to the link by hand or forged into one half of the link. f. EBB Anchor Chain. BBB anchor chain is an all-welded steel chain of uniform links without studs. r,r. Wrought-Iron Anchor Chain. Wroughtiron anchor chain possesses high resistance to shock loads and, because of the ductile nature of the material, will elongate when overloaded and show visual signs of danger. h. Cast Steel Anchor Chain. Cast steel anchor chain has a tensile strength approximately 30 percent greater than wrought-iron or firewelded steel chain of the same diameter. It can be distinguished by thE;) fact that the studs are solid and an integral part of the links, with each common link in the chain identical. 2s:r. Anchor Chain Components and Accessories The following is a list of common anchor chain components and accessories. Figure 213 illustrates several components in a typical makeup of anchor chain. a. Detachable Links. The detachable link is used as a connecting shackle for joining shots of anchor chain. It has replaced the U-shaped connecting shackle and the Kenter connecting shackle which were used for this purpose. The AGO 5244A DETACHABLE BENDING c. Mooring Shackles. Mooring shackles are LINK SHACKLE ~ fabricated from forged steel with a 6-inch opening between the jaws and are used for attaching anchor chains to mooring buoys. An OUTBOARD additional special lightweight mooring shackle, co••~ SWIVEL END LINK HARP not possessing the full strength of the anchor cable, is used with some heavy equipment. Figure 213. Typical makeup of anchor chain. Mooring shackles with a 7-inch opening between the jaws are used where large buoy rings are encountered. Navy-type detachable link consists of a Cshaped line with two coupling plates which d. Detachable End Links. This link although form one side as well as the stud of the link. resembling the detachable link, is pear-shaped A taper pin that holds the link and plates toto permit a direct attachment between a common link of shackle, end link, and detachable gether is locked in place at the large end by a lead plug. The chief advantages which the link. detachable link has over the U-shaped connecte. Shackle Tool Sets. Shackle tool sets, in ing shackle are the following: cluding spare taper pins and locking plugs, are (1) The detachable link is approximately provided for use in assembling and disassemblthe size and shape of the common links ing detachable links. of the chain with which it is designed f. Chain Swivels. Chain swivels are furnishedto be used; therefore, it will ride as as part of the outboard swivel shot and servesmoothly over the wildcat, in both the to minimize kinking of the anchor chain. flat and vertical positions, as the com mon links. g. Mooring Swivels. Mooring swivels are (2) The use of long shots (40 to 45 fabricated of forged steel and have two detachable links, one at each of the swivel. They are fathoms) immediately inboard of the outboard swivel shot is not necessary used to facilitate mooring. with the detachable link because there h. Mooring Hooks. Mooring hooks are made is no disadvantage in having it on the of galvanized or forged steel and are used to wildcat when the chain is vertical and facilitate mooring to a buoy.the windlass is under the strain of i. Outboard Swivel Shots. Standard outboard breaking out the anchor. swivel shots, consisting of detachable links, (3) Enlarging the end link to take the eye swivel, end link, and bending shackle, are usedof the U-shaped shackle is no longer on most vessels to attach the anchor chain tonecessary. The detachable link can be the anchor. These shots vary in length up tothreaded through a common link, thus approximately 61f2 fathoms and are also termed permitting the omission of these enbending shots. The taper pin in the detachablelarged links. This eliminates the main link, located in the outboard swivel shot, iscause of anchor chain slipping on the additionally secured with a wire-locking clip. wildcats and allows the pockets of the wildcats to be designed to closer j. Housing Chain Stoppers. Most standard housing chain stoppers (fig. 214) are used for tolerances. holding the anchor taut in the hawsepipes, for (4) Because both ends of the detachable riding to an anchor, or for holding the anchorlink are closed, they do not catch on chain is disconnected. When riding to an anchor the hawsepipe or deck fittings and, as with more than one stopper in use, the largea result, have reduced the losses of chain stopper wrenches are used to equalizeanchors and chains. strain on the stoppers. Special housing chain b. Bending Shackles. Bending shackles are stoppers, such as devil's claw or pawl-type used for attaching the anchor to the anchor stoppers, are used where space limitations do not permit use of standard stoppers. chain. AGO 5244A 276 DETACHABLE LINKS Figure 214. Typical housing chain stopper. 258. Maintenance and Repair Only minor repairs can be performed by shipyards other than those authorized. Overhauling and heat treating of high strength welded chain and appendages can only be accomplished by shipyards meeting requirements of the Department of Defense. a. Maintaining Chain Identification Marks. Each shot of anchor chain usually bears a serial number that is stamped, cut or cast on the inner side of the end links at the time of manufacture. In the case of cast steel chain, this number is preceded by the letters C.S. If an end link is lost or removed from a shot, this identification number should be cut or stamped on the side of the new end link of the altered shot. The studs of forged-iron and forged-steel, fire welded links have the wire diameter of the links imposed on the reverse side, with the opposite side indicated in raised letters. Cast steel and some types of high strength welded steel chain have these mark ings on the studs of alternate links only. AGO 5244A b. Restrictions As to Use of Chain Appendages. During makeup or repair, anchor chain appendages should be restricted to the purposes for which they are intended. The intended uses are obvious, but particular attention should be given to the uses of the detachable link (para 257a) and the housing chain stopper (para 257i). c. Periodic Maintenance. Annually, all anchor chains of sizes up to and including llh inches should be arranged on deck and examined throughout their entire length. If necessary, they should be scaled and cleaned of rust and foreign matter. Detachable links should be disassembled (fig. '215), examined for excessive wear or corrosion, and replaced as necessary. When the stock detachable links is exhausted, new high .sb:-ength detachable links, with proof loads equal to the breaking load of the standard detachable links, will replace the standard de- MARK TO ASSIST ASSEMBLY--:'-~ ASSEMBLED LINK LEAD PELLET--a "'""'"'"" '"~ LUGS OVERLAP AND ARE HELD TOGETHER BY FORELOCK PIN LUGS /\. ~~ Figure 215. Disassembly of detachable link. tachable links in sizes from % inch to 1% cause thickening of the paint. The addition of inches inclusive. Before reassembly, the new solvent will remedy such a condition. links should be coated with white lead. The deNote. Vessels receiving anchor chain that has been tachable link, located in the outboard swivel coated with either red-lead primer or zinc-chromate shot, is fitted with a corrosion resisting steel primer and black enamel or biack-asphalt varnish should leave this coating intact and cover it with one coat locking wire which serves to hold the taper pin of black enamel, Military Specification MIL--P-15146. in position. Disassembly of this link requires the removal and probable destruction of the d. Replacement of Worn Chain. If any part locking wire; a replacement wire of the same of the chain has been reduced by corrosion or type should be obtained prior to removal for wear so that the mean diameter is reduced inspection. Shackle bolts, locking pins, and to 90 percent of its normal diameter, that part swivels should be carefully examined, put in should be replaced, provided, it can be acorder and, if needed, coated with red-lead complished and the diameters of the remaining primer, Military Specification MIL-P-17545, links allow continued use. If it appears unecoor zinc-chromate primer, Federal Specification nomical to replace worn parts, the chain should TT-P-645 or Military Specification MIL-P-be surveyed. If replacements are made, the new 8585, followed by one coat of black enamel, links, shackles, or parts should be heat-treated, Military Specification MIL-P-15146. When proof tested, and, in the case of wrought iron, facilities permit, the chain links should be preheat-treated again. In each case a complete reheated prior to both the prime and final paintport should be formulated containing the foling operations. A temperature of 250°F. (121 °lowing information: material composition of the C.) is recommended, but a lower temperature chain, shot number, length of each shot, natureof 150°F. (66°C.) will decrease the drying of work actually performed on the chain, datetime. In cold weather, apply some heat to counof such work, and cost. This report shouldteract the natural thickening of paint; this can reference the file number of the correspondence be accomplished by an immersion-type electric heater or a steam coil. When left standing for authorizing the work involved. This report should also include disposition of the chaina considerable period, the turpentine substitute after the heat treatment. can evaporate to such an extent that it will Section Ill. ANCHOR WINDLASSES power source. These classes include electric 259. General hyraulic drive, electric drive, steam drive, and Windlasses are installed on vessels primarily hand-operated windlasses. The essential parts for handling and securing the anchor and of a windlass, regardless of type and class, are anchor chain. Most windlasses are provided the primer mover, gear transmission, chain with capstans or gypsy heads which are used wildcat and brake, head for handling line, and for handling line or for mooring and warping control means. Horizontal-shaft windlasses are operations. Windlasses are usually located in usually a self-contained unit with the windlass the bow of the vessel for handling the bower and primer mover mounted on the same bed Craft Utility (LCU) is anchors. Landing plate. Vertical-shaft windlasses have the power capable of retracting from a beach by the use source located below the deck with only theof 150°F. (66°C.) will decrease the drying time. wildcats and heads showing above the deck. typical anchor windlass, chain, and anchor a. Electric Hydraulic Drive Windlasses. In assembly are shown in figure 216. the hydraulic drive windlass (fig. 217), power 260. Types and Classes is transmitted from an electric motor through a variable stroke hydraulic transmission in There are two general types of windlasses order to obtain a wide range of output speed. installed on most vessels: The horizontal-shaft The motor, transmission, reduction gearing,type and the vertical-shaft type. These types and controls are called a power unit. Electricare subdivided into classes, depending upon the AGO 5244A 278 RIDING CHOCK (FAIRLEAD) Figure 216. Anchor windlass, chain, and anchor assembly. hydraulic drive windlasses on large vessels have two power units, one to drive each half of the windlass. Interconecting piping and transfer valves allow selection of power unit to be used. The electric motor for an electric hydraulic drive windlass is usually a single speed, squirrel-cage type motor and is equipped with a magnetic brake designed to hold 150 percent of the motor rated torque. The brake activates upon loss of power to prevent the anchor from dropping in case of power failure. The electric motor is coupled to the hydraulic pump of the transmission. Fluid, under pressure is delivered from the hydraulic pump to the hydraulic motor. The pump end .of the transmission is commonly called the A end and the hydraulic motor end is called the B end. The B end is connected to suitable reduction gearing which drives the windlass shaft. The hydraulic motor is usually mounted vertically on the reduction gear case. Windlass speed is determined by varying the stroke of the hydraulic pump. This is performed by control handwheels, located on the weather deck and at the pump. An indicator at each handwheel shows the stroke of the pump in percentage of full stroke. Adjustable stops normally limit the stroke to 90 percent but can be increased to full stroke, if necessary, to compensate for pump wear. When starting the electric motor, it is essential that the hydraulic pump be offstroke to prevent overloading the electric motor. This is accomplished by a centering device and an interlock switch which the operator uses to place the pump in a no-stroke position at the control handwheel. The stroke at which the pump is set determines the quantity of hydraulic fluid delivered to the hydraulic motor, which in turn determines the speed of the motor, as its displacement is constant. The control handwheels also control the direction of rotation of the windlass and are marked accordingly. Relief valves in the hydraulic piping are set to prevent excessive strain on the chain and on the windlass driving mechanism. Relief valves should be tested and set during scheduled overhauls. A combined storage and expansion tank is provided for each power unit. The tank is located above the highest point in the hydraulic system, usually on the underside of the main deck. Replenishing and circulating lines connect the tank to the hydraulic system. A replenishing valve maintains fluid level and eliminates air from the active system. The circulating lines provide thermal circulation and cooling of inactive fluid. A locking head, AGO 5244A located above the reduction gear case, permits disconnecting the wildcat shaft from the drive for dropping anchor. The wildcat shaft is equipped with a lined brake, controlled by brake handwheels on the main deck and in the windlass room. The brake is capable of controlling and ,stopping the free fall of an anchor and chain at 15-fathom intervals for a depth of 60 fathoms. When disengaging the locking head, the brake should first be engaged. Vertical capstan heads, located port and starboard on the main deck, are driven through vertical shafting from the reduction gears. Because · locking heads are not installed on the capstans, they will rotate during windlass operation. When using the capstan, the wildcat shaft locking head should be disengaged and the wildcat held by the brake. b. Electric Drive Windlasses. Electric drive windlasses are powered by an electric motor which drives the wildcat and head directly CONTROL STAND INDICATOR through suitable reduction gearing. Qargo, transport, and auxiliary vessels are generally provided with a horizontal shaft, self-contained, electric drive windlass with the motor and reduction gearing located on the windlas bedplate situated on the open deck. This windlass has combined facilities for anchor handling and warping and consists of two declutchable wildcats on the main shaft and two warping heads on the shaft ends. It is driven, through suitable reduction gearing, by a reversible variablespeed, 230-volt de electric motor provided with a magnetic brake to hold the load in case of power failure. Controls are of the dual magnetic type to provide both straight and reversing characteristics for warping and dynamic lowering characteristics for anchor handling. Transfer switches allow selection of the proper characteristics. When used for anchor handling, the control usually provides five speeds in each direction, with adequate torque in hoist direc- REDUCTION GEARS SECTION THROUGH PORT WINDLASS Figure 217. Electric hydraulic drive windlass. AGO 5244A tion and dynamic braking in all lowering points. For warping, the control characteristics are substantially identical in both directions. A single controller master switch is provided and located on the deck adjacent to the windlass. Before starting an electric drive windlass, a thorough inspection should be made to insure proper lubrication in accordance with the applicable lubrication chart. c. Steam Drive Windlasses. While steam drive windlasses provide a good range of speed and smooth acceleration, their use on modern vessels is limited to tankers, some cargo vessels, and transports. Steam windlasses are of the horizontal-shaft type, driven through spur gear reductions by two single-cylinder, horizontal steam engines, one at each end of the crankshaft. Reversing and speed control are obtained by use of a hand operated piston valve which reverses and regulates steam flow to the valve chests. The main cylinder valves are also of the piston type. Two wildcats and two warping heads are usually provided. d. Hand-Opemted Windlasses. Hand-operated windlasses are limited to use on small boats where the weight of the anchor gear is such that it can be ·handled in a reasonable time and without excessive effort. A pumpbrake type, hand-operated windlass is installed on some boats where a power source is not available. This windlass will handle up to 2000pound anchors and 1%-inch die-lock anchor chains. It is operated by two pump levers fitted into a walking beam. By pressing the levers alternately, power is transmitted to the windlass shaft through the linkage, the friction shoes, and the locking head. Each friction shoe grips the locking head on the up stroke and releases it on the down stroke. Handbrakes are provided on the wildcat for control when dropping the anchor. The horizontal-shaft type, hand-operated windlass has two wildcats, but handling of only one anchor at a time is recommended. 261 . Components The following components are common to all windlasses: a. Wildcats. The windlass wildcat is a special type of drum of sprocket construction to handle AGO 6244A the anchor chain links. The outer surface is provided with flats or pockets in which the flat chain links lie. At each end of the pockets, lugs known as whelps, which contact the end of the flat link, are provided. A central groove in the outer surface accommodates the vertical links which are not in contact with the wildcat at any point. The wildcat, which brings in the chain, is rotated by the windlass power source. b. Locking Heads. Windlasses are provided with a means of disengaging the wildcat from its power source. This is known as a locking head and permits free rotation of the wildcat when letting out chain. Locking heads usually consist of two sliding block keys which can be shifted to key together a drive spider and the wildcat. The drive spider is keyed to the windlass shaft while the wildcat is carried on bearings and is free to rotate except when the locking head keys are engaged or when the wildcat brake is set. c. Windlass Brakes. Each wildcat is equipped with an externally contracting, flat band brake operated by a handwheel. This brake can be used to hold the anchor and chain and to control the rate of descent. This brake should be inspected regularly for wear, maladjustment, and defective parts. Consult the applicable windlass technical manual for' detailed instructions for maintenance and adjustment of the brake. Failure of the wildcat brake can result in loss of the anchor and chain. d. Capstan Heads. Capstan heads fitted on windlasses are keyed to the drive shaft and rotate when the windlass power source is turning. When using the capstan heads the wildcat locking head should be disengaged and the wildcat brake applied. The capstan heads will operate independently of the wildcats. When using the wildcats, however, the capstan heads will always rotate. 262. Maintenance In addition. to maintenance instructions contained in applicable manuals, the following items should be considered. a. General. (1) Maintenance and adjustment of equipment should be continued during peri ods when it is not in use in order to prevent deterioration and to provide dependable operation when required. Inspect windlass weekly and operate as necessary to insure that equipment is in proper condition. (2) Windlass brakes are designed to stop and hold the anchor and chain. Due to wear and compression of the brake lining, the clearance between the brake drum and band will increase with use. Means of adjustment are provided on all brakes and should be used if inspection indicates excessive clearance. In most cases, loss of the anchor and chain is attributed to failure of the brake. (3) Lubrication instructions are provided in the applicable technical manual lubrication chart and should be followed as to grades of lubricant, frequency of application, and points of application. ( 4) If the windlass is not used frequently, it should be lubricated before each operation in accordance with applicable technical manual. Rotation of the windlass by power during lubrication will distribute the lubricant evenly. The locking mechanism can be disen gaged and the chain held by engaging the wildcat brake. ( 5) After using the windlass, lubricate the equipment in order to prevent rusting and freezing of adjacent parts and to protect finished surfaces from corrosion. (6) The mounting frame should be checked to insure that nuts and holddown bolts are tight. b. Maintenance of Electric Hydraulic Drive Windlass. (1) The hydraulic transmission, used for operating electric hydraulic. windlasses, is manufactured, with close tolerances between moving and stationary parts. To maintain these clearances and prevent wear, it is necessary that every precaution be taken to keep foreign material out of the hydraulic system. Only clean fluid should be used for filling and replenishing the system. Fluid containers should be clean and the fluid should be strained as it is poured into the system. Interiors of valves, piping, and fluid reservoirs should be cleaned before installation to remove all foreign material. (2) Hydraulic systems perform best when they are free from entrapped air which usually enters when filling the system with fluid. Presence of air is indicated by noisy operation or by variation in hydraulic motor speed, especially slowing down under load. Air vent needle valves are provided at high points on the piping. When filling the system, these valves should be used to allow escape of air by manipulating the valve until clear fluid is observed. A few turns of the transmission, by power, will force the air from the cylinders and valve plate ports; by opening the air valves at high points, the air will escape. If there are still indications of air in the system, operate the hydraulic transmission for about 20 minutes at reduced stroke and high pressure; this will force the air from the active system. (3) Relief valves prevent excessive strains in the chain and the windlass driving mechanism. These valves are set to relieve at 200 percent of the normal hydraulic working pressure. Relief valves should be tested and set during regularly scheduled shipyard overhauls. c. Maintenance of Electric Drive Windlass. (1) Inspect windlass weekly, operating as necessary, to insure that equipment is in proper condition. (2) Check electrical components to insure that gaskets and seals are in place and that contactors are in good operating condition. ( 3) Refer to applicable technical manual for instructions on maintenance and repair of electrical parts. AGO 5244A • d. Maintenance of Steam Drive Windlass.· (1) Steam drive windlasses are not designed to operate on full boiler pressure. The rated capacity of the windlass is based on a 100-or 125-psi gage steam pressure, which is controlled by a pressure regulator in the steam line. Insure that regulator is in proper condition and that rated steam pressure is maintained. (2) Drain cylinders, control valves, steam chests, and piping before operating windlass. (3) Keep equipment clean and properly adjusted at all times. AGO 5244A CHAPTER 14 DECK AND HULL FITTINGS Section I. DECK FITTINGS 263. General Deck fittings are those items on the deck provided to aid in mooring, towing, loading cargo, refueling, and docking and for use with ground tackle. They are fabricated from strong metals, capable of withstanding long and constant use. Deck fittings are securely mounted to a strong area of the deck oradjacent area. 264. Mooring and Gear FiHings Mooring and gear fittings are primarily used to moor, tow, and dock the vessel, to handle cargo and other pieces of equipment, and to provide access through a surface. Mooring and gear fittings must have adequate strength in their design and method of attachment. Typical locations of mooring and gear fittings on an Army vessel are shown in figure 218. a. Lifting Eyes. There are many designs of lifting eyes (g. 219) and various ways of attaching them. One type has a pad for a base and is secured by viets or bolts. Another type has a threaded shank and is screwed into either a pad or a threaded hole. Whatever the means of attachment, the attachment must be to a strong point of the structure. Eyes installed on decks are frequently attached to deck beams. Reinforcement plates are sometimes added to strengthen their attachment. Eyes can have a ring through them or not. In use, a hook on the end of a sling is normally put through the eye or ring. Eyes with rings give a greater degree of angle leverage and are useful for securing ends of tackle. b. Cleats. Cleats (fig. 218) have two projecting arms or horns to which a halyard or other line is belayed. They can be forged of one piece of metal or consist of two pieces. Cleats are se cured to the deck, side plating, or a stanchion. They are frequently used for attachment of temporary mooring lines on small vessels. c. Chocks. A chock is an opening through which hawsers and mooring lines are passed. It can be cast or fabricated of steel, can have rollers or not, and can be opened or closed at the top. Typical chocks are shown in figures 218 and 220. d. Bow Plates. A bow plate consists of several items, such as fairleads and an end socket for a jackstaff installed on the bow. Bow plates are used on special installation or on small vessels. e. Bitts. Bitts (fig. 218), also known as hallards, are posts or columns that extend above the deck. The riding and stern bitts shown in figure 218 are used for mooring and towing. Bitts for large vessels are usually cast or fabricated of steel; however, some bitts are made from fiat plates welded together. A fabricated cross bitt and a cross section of a fabricated cone section double bitt are shown in figure 221. On small vessels, a cross bitt can simply be a wood post with a rod run through it. The capacities of various size fabricated steel bitts are listed in table XX. The moments used to show capacity are obtained by multiplying the pull on the bitt in pounds by the height above the base at which the pull is exerted, in inches. f. Removal and Installation of Lifeline Stanchions and Other Deck Fittings. If lifeline stanchions (fig. 222) and stanchion braces are secured to wooden decks by screws, the screws should be replaced by bolts. The bolts should extend through the deck where possible. If the stanchion or brace blocks are cracked or deteriorated, new stanchion or brace blocks should be installed. In securing stanchion or AGO 5244A DETAIL A STERN BITT SEE DETAIL C DETAIL B DETAIL C DETAIL D DETAIL E SEE DETAIL B ANCHOR STORAGE CHOCKS SEE DETAIL A Figure 218. Typical locations of mooring and gear fittings. AGO 5244A THREADED SHANK Figure 219. Lifting eyes. Table XX. Fabricated Steel Bitt Capacities Maximum diameter Maximum Diameter of wire circumference Capacity bitt rope of manila rope (moment in (inches) (inches) (inches) inch-pounds) 4 % 4 6 % 6 8 % 9 10 11,4 12 12 1% 14 1% 16 1% 18 21,4 20 23,4 103,000 250,000 499,000 894,000 1,095,800 2,014,000 2,678,000 4,030,000 5,855,000 brace blocks to the deck, surfaces where the flange rests on the block and where the block rests on the deck should be covered with white lead. Grommets, made of wicking and worked through with white lead, should be looped around the bolt holes on both surfaces to insure a proper seal around bolt holes. g. Mast Socket. Some vessels use a mast socket (fig. 223)) bolted to the pilot house or deck. In areas where bolts are impossible to use, the socket can be secured with screws. If the socket or the block under it is to be reattached, use the method of calking described in f above. CLOSED CHOCK ~ENCHOCK ~ ~ROLLER CHOCK OOUBLE-ROLLER CHOCK~ Figure 220. Chocks. h. Emergency Tiller Deck Plate. An access in the deck is frequently used on small vessels to insert the emergency tiller (para 192) into or over the rudder posts or stocks. Frequently, a flange with a threaded plate fitting is attached by screws over the hole in the deck. A AGO 6244A FABRICATED CONE SECTION DOUBLE BITT FABRICATED CROSS BITT Figu1·e 221. Bitts. LIFE LINE STANCHION -----<--1 Figure 222. Typical footrail or toerail and lifeline stanchion. AGO 5244A key is usually provided for removal of the plate from the center of the flange; however, some plakes can be removed with a screwdriver. If a key is used to remove the plate one or more must be aboard the vessel so that the crew can use the emergency tiller. The keys should be in good shape with their prongs even and not broken. If the section of the deck into which the deck plate is fitted has been shifted or replaced, the hole for the deck plate must be centered above the rudder stock or post, for the emergency tiller to function properly. The emergency tiller should be installed and operated to assure proper functioning. The deck plate must be easily removable from the flange. If the threads or retaining teeth are defective, they should be retapped or deck plate replaced. If the deck plate was designed to be watertight, it must remain so. The flange should be sealed under its face where it contacts the deck. 265. Railings Railings are used to prevent accidental falling overboard or into a hole. They are also in stalled in companionways and passages for use in rough water. a. Deck Railing Stanchions. Stanchions (fig. 222) can be forged of round iron or loop iron or can be made of steel pipes. The railings are welded to the stanchion or pass through holes drilled or forged through the stanchion. Braces for stanchions are either welded or attached by a pin and eyeplates. The stanchion can be welded directly to the deck, set in palm brackets attached to the gunwale, or set in eyeplates I with pins or other fastenings. Stanchions I should not be installed to interfere with deck / wash along the gutterways. Any repair or replacement work should r.esult in a product at least as strong as the original. b. Footrail or Toerail. A footrail or toerail (fig. 222) fits around the outer edge of the deck on the outside of the lifeline stanchions. The rail extends up about 3 inches from the deck Figure 223. Mast socket. Figure 224. Typical deck handrails. AGO 5244A ~----- --~ ~- HOSE Figure 225. Typical fuel tank filler pipe deck plate fitting. on small vessels and much higher on larger vessels. This is installed to prevent personnel and equipment from sliding overboard. It is made of wood or metal, depending upon the type of vessel and where it is operating. The footrail or toera~l is sometimes used on catwalks or walking flats in engine rooms around engines and machinery. c. Cabin Top Handrails. Cabin top handrails (fig. 224) are provided to enable personnel to maintain balance while walking around the sides of the cabin or other structures extending above the deck. They can be constructed of wood or steel. If installed on a nonmetallic surface, bolts should be used for securing supports with flanges. FRESH WATER FILLER CAP WRENCH Figure 226. Typical fresh water tank filler cap deck fitting. 266. Through-Deck FiHings Through-deck fittings are designed to allow passage through a deck opening and to make that opening watertight and/or spray and deck wash proof. a. Fuel Tank Filler Pipe Deck Plate. The fuel tank filler pipe deck plate (fig. 225) is designed to fit flush with the deck surface. It is a flange fitting with a welded neck, which is connected, to piping wtih a coupling. The deck plate is threaded to receive a flat threaded cap having two holes for a special type of opening . wrench. The-flange deck plate and filler cap are made of brass or bronze. Fuel filler caps are marked FUEL ONLY and are secured to the inside of fuel piping with a piece of chain or a lanyard. ' b. Anchor Deck Pipe and Cap. The anchor deck pipe and cap (fig. 218) allow lines to be passed through and stored under a deck, leaving one end on deck usually connected to an anchor. A nipple with a flange base is fastened to the deck and is covered by a pipe cap that fits over the nipple. The nipple and cap are slotted so not to interfere with the line extending through the fitting when the cap is installed. If the anchor deck pipe is removed from the deck, it should be sealed against the deck when reinstalled. A length of chain or lanyard is connected to the deck pipe and cap to prevent losing the cap overboard. Section II. 267. General Hull fittings are various types of hardware items such as sea chests, valves, ducts, ventilators, pumps, vent lines, and connecting fiittings. They are furnished for the purpose of intake and exhaust of air, liquid, and light and are especially designed for watertightness. 268. Sea Chests and Valves a. Bilge Bulkhead Drain Check Valve. Bilge bulkhead shut-off drain check valves (fig. 227) are designed to permit flow in only one direction. They are used in drain lines to prevent reversal of flow. Care must be taken to make certain the valves are properly installed. Most of the valves have an arrow or the word INLET cast on the valve body to indicate direction of flow. If a valve lacks such indication, check closely to be sure that the flow of liquid in the system will operate the valve in the proper direction. The port in a drain valve is closed either by a disk, bolt, or plunger. The valve opens when the pressure on the inlet side is greater than that on the outlet side and closes when the reverse is true. These valves are made with threaded, flanged, or union faces, with screwed or bolted caps, and for specific pressure ranges. The disk of the valve is raised as soon as the line pressure of the fluid entering below . the disk is of sufficient force. While the disk is raised, continuous flow takes place. If for any reason the flow is reversed or if back pressure builds up, this opposing pressure forces the disk to seat, thus stopping the flow. The operation of this valve is similar to that of c. Fresh Water Tank F,itting and Deck Plate. The fresh water tank fitting and deck plate (fig. 226) are installed through the deck similar to the fuel tank fitting described in a above. The cap is marked FRESH WATER ONLY and must be opened with a special wrench. The key type wrench used to open the water cap differs from the fuel cap wrench in configuration and spacing between the lugs. This spacing of lugs on the wrench prohibits accidentally opening the wrong cap when loading liquids. The cap should be secured to the inside water piping with a piece of chain on a lanyard. HULL FITTINGS a swing-check valve, except that the valve disk moves in an up-and-down direction instead of through an arc. b. Toilet Intake and Discharge Gate Valve and Seacock. (1) Gate valves are installed where a straight flow with a minimum amount of restriction is desired. Most gate valves have a wedge-shaped gate, although some have a gate of uniform thickness. The gate is connected to the valve stem and is positioned by a handwheel or a straight on and off handle. An example of a gate valve is shown in figure 253. The gate valve is commonly used for the intake of raw INLET PORT Figure 227. Typical bilge bulkhead shut-off drain check valve (horizontal lift check). AGO 6244A UPPER DUCT SECTION JAMNuT-® Figure 229. Mushroom ventilator. water for sanitary conditions. The seacock is also used for the discharge of water such as waste water from wash basins, toilets, and showers. (2) Gate valves are installed against the bulkhead. Intake globe valves are inFigure 228. Exhaust blower and duct. stalled below the waterline, and out- BULKHEAD BLANK PLAIN THREADED MALLEABLE FLANGED FLANGE FLANGE FLANGE UNION CAST OR WROUGHT STEEL FLANGE WELDING NECK FLANGE SOCKET WELDING FLANGE VAN STONE FLANGE Figure 230. Typical standard flanges used for bulkhead fittings. AGO 5244A put gate valves are installed above the waterline. These valves are used for either engine-driven pumps or hand pumps. c. Ducts and Ventilators. (1) Half-cowl type ventilators are primarily used on small vessels and are fitted to the sides and decks. Their purpose is to ventilate the lowest parts Full size ventilators are used for the comfort of the crew and for ventilation of the engine room and storage areas (fig. 228). Fuel compartments are ventilated by the use of vent pipes. Full size ventilators are power-driven EXHAUST HULL FITTING ETS I L__ FLAHGE----.,1 through a blower system on deck. This system forces fresh air into all compartments, forcing out foul air through a series of exhaust fans. (2) All air is forced through the vessel by a series of ducts. The main intake duot ventilator (fig. 229) is a mushroom type. It is connected to the blower systems on deck and forces air through smaller ducts into each compartment. The fresh air ducts are fitted to the lower part of the bulkhead. The exhaust ducts are secured to the overhead and expel through the exhaust ventilator on deck. 269. Through-Hull Fittings a. Bilge Pump Fitting. The bilge pump through-hull fitting is a bronze welding necktype fitting. It is installed through the hull and connects to the bilge pump discharge line with a standard bulkhead-type flange fitting. A valve of some type is normally installed in the line inboard at the fitting, to prevent sea water entry. An example of a welding-neck flange fitting is shown in figure 230. b. Fuel Vent Line Fitting. The fuel vent line fitting is similar to the bilge fitting described in Figure 231. Typical engine exhaust fitting. Figure 232. Bucket-type propeller guard for steel hulls. AGO 5244A a above. The fitting is made of brass or bronze and connects the vent pipe to the fuel tank through the deck and is fitted with return bends or goosenecks. The vent pipe deck opening is protected with a wire screen cover. All vent pipes are fitted with a type of valve to permit closing in case of emergency. c. Sink Drain Through-Hull Fitting. This through-hull fitting is a welded-neck flange fitting (fig. 230), the same as described in a above. A valve, normally flutter-type is installed inboard next to the fitting to prevent entry of sea water. d. Engine Exhaust Fitting. The engine exhaust through-hull fitting is a bronze or brass fitting which connects the engine exhaust piping through the hull. The inner and outer flanges of the fitting are connected by nuts and bolts. Flutter valves are sometimes installed inboard the flange to prevent the entry of sea water. Types and sizes of all through-hull fittings vary with the type and size of vessel. I-+---TRACK Figure 233. Gate-type propeller guard for wooden hulls. AGO 5244A e. Propeller Guards. There are two types of propeller guards, the bucket-type and the gatetype. The bucket~tpe is used on slow moving vessels, such as landing craft, which operate in shallow waters or close to shore. This guard is installed around the propeller and welded to the hull of steel vessels (fig. 232) . On wooden hulls, the gatetype guard is secured through the hull with bolts and steel bracing (fig. 233). The gate-type guard is made of bronze or brass and is secured on the port and starboard sides by a track or is hinged to the transom so that it can be let down by a sleeve or line. f. Salt Water Scoop and Screens or Grills. The salt water scoop is located on the bottom of the hull with the grillport of the scoop forward. This arrangement enables the raw water pumps to pick up water while underway. Scoops are bolted through the hull flanges on wooden hulls. On steel hulls, they are welded to the flanges. All scoops are grilled or screened with heavy brass or bronze wire to prevent seaweed or other foreign matter from entering the raw water lines. A typical salt water scoop and grill are shown in figure 234. g. Replacing Through-Bulkhead Fittings. When necessary to replace through-bulkhead fittings, use a welding neck-type flange on one side and a flat bulkhead-type on the other side. Gaskets must be used between the flange surface and the bulkhead for watertightness. Piping through the flanges should be calked or wrapped to prevent vibration or leakage. If a hot pipe is to be installed through the bulkhead, it should be covered with an insulating material to prevent excess heat in other compartments Figure 234. Typical salt water scoop and grill. and also to serve as protection for personnel against burns. h. Replacing Through-Hull Fittings. Replace through-hull fittings (fig. 235) as follows: (1) Remove connection pipes and throughhull fitting. (2) Indicate location for new hull fitting by placing an X mark on surrounding planking as shown in figure 236. (3) Repair and paint planking as necessary. ( 4) Center punch and drill hole at location determined by X mark. ( 5) Pack flange with white lead or gasket material to insure watertight installation. (6) Install flange and reconnect piping. Note. When the fitting is for a hot pipe, clearance must be provided for asbestos covering while marking and drilling hole. All hot pipes must be wrapped with asbestos covering before installation. AGO 5244A STEP l. CUT RECESS FOR OUTER EDGE OF FLANGE STEP 4. APPLY WHITE LEAD TO RECESS FOR FLANGE STEP 2. CUT THROUGH-HULL OPENING STEP 5. DRILL BOLT HOLES WITH FLANGE AS GUIDE STEP 3. CHISEL OUT RECESS FOR FLANGE STEP 6. INSTALL FLANGE BOLTS Figure 235. Replacing through-hull fitting. AGO 5244A ,,,,,,,,___ FITTING OUTLINE ~--PAPER PLANKING TO BE REPLACED PLANKING TO REMAIN STRAIGHTEDGE MARKS Figure 236. Method for locating fitting in new planking. AGO 5244A CHAPTER 15 PIPING SYSTEMS Section I. GENERAL INFORMATION 270. General· Piping system on vessels are used to carry steam, air, salt water, fresh water, fuel oil, lubricating oil, gasoline, and other fluids. Although each piping system is designed to serve one special purpose or more, all piping systems serve the same basic purpose of transfer ring fluid from one place to another, for storage or for use. 271. Definitions a. Pipe. Specified by iron pipe size (IPS). Designations by size and by schedule for wall thickness, such as standard weight schedule 40, extra strong schedule 80, and double extra strong schedule 160. b. Tubing. Specified by outside diameter or iron pipe size, to where wall thickness is generally specified in decimals of an inch. Tubing normally is intended for joining by methods other than threading such as brazing or welding. c. Piping. An assembly of pipes or tubing, valves, fittings, and related components which form a whole or a part of a system for .transferring fluids. d. Potable Water. Water of drinking water quality. e. Feed Water. Water of boiler water quality. f. Fresh Water. A collective term which refers to both fresh water and potable water. g. Fresh Water Drains. A collective term referring to drainage from steam heating systems and warming-up drainage from other high pressure steam systems. These drains are of feed water quality and are returned. to the boiler condenser system. h. Cut-Out Valve. A valve that is normally to be fully opened or closed. i. Throttle Valve. A globe-or angle-type valve especially designed to control rate of flow. 272. Check Prior to Pressurizing Piping Before pressurizing any portion of a piping system for operation or testing, operate all downstream valves, except those which would pressurize the system from another source, to insure freedom of operation. Verify that all valves and equipment in or connected to this portion of the piping system are in the required position or condition. Warning: Failure to observe this requirement can result in injury to personnel and damage to material. Admitting steam or hot water into an open and occupied boiler and opening circulation water valve to an open condenser must be avoided. 273. Steam Supply Systems Steam supply systems are installed to furnish energy for operating vessel propulsion turbines and associated auxiliaries, generator turbines, boiler auxiliaries, distilling plants, air compressors, oil heating systems, space heating systems, and a variety of miscellaneous services. Steam supply systems generally are operated'· independently by machinery groups, but suitable connections are provided so they can be cro~s-connected for economy of operation during cruising or for emergency operation due to equipment malfunction or damage. 274. Drain Collection Systems Drain collection systems are provided to remove condensate that collects in steam piping systems and equipment and to provide fresh AGO 6244A 297 and contaminated water drainage from other services. Most vessels, depending upon their performance and function, have an extensive drain-collecting installation. The principal drain collection systems in a vessel include the high pressure steam drainage system and the service steam drainage system. a. High Pressure Steam Drainage System. This system collects drainage from steam piping systems and steam equipment operating at pressures of 15Q psi and above, and returns it to the deaerating feed tanks or feed water heaters. Each drainage branch line is fitted with a strainer, a trap, and cutout valves. Bypassing these components is a warming-up branch line which discharges to the fresh water drain-:-collecting main. b. Service Steam Drainage System. This sys tern collects drainage from steam piping systems and steam equipment outside machinery spaces which operate at pressures under 150 psi. This includes services such as space heaters, laundry, tailor shop, galley, and pantry equipment. Drainage from this system is discharged into the fresh water drain-collecting tanks. On large vessels, the system discharges to service steam drain-collecting tanks located in the machinery spaces. Air ejectors are provided to maintain these tanks under a vacuum to insure proper functioning of the drainage system. The contents of the tanks are discharged by floatoperated pumps to the condensate-discharge system. In addition, each tank has gravity drainage connections to the fresh water draincollecting tank and to the bilge-sump tank in the same space. Section II. METHODS OF JOINING 275. General Current practice is to use welded joints in carbon steel, alloy steel, and other weldable piping to the maximum practicable extent. In these welded systems, the throttle valves and valves which operate automatically or semiautomatically, such as safety, relief, regulating, and governing valves, are provided with flanged connections to facilitate removal for repairs. Other components which have been welded into the piping system have been located, to the maximum possible extent, so they can be accessible for repair, reseating, or overhaul while installed. Complex assemblies, such as assemblies of valves, strainers, and traps in the high pressure drainage system, which cannot be repaired satisfactorily while installed and ordinarily require repeated removal, are also provided with sufficient flanged joints to permit their removal as assemblies. In many cases, welded-in cutout valves adjacent to equipment or machinery have been provided with one flanged end so that the machinery or equipment can be easily removed,. The above criteria are generally applicable also to systems that have brazing components. In systems such as Freon piping and heating coils in tanks where system tightness is more important than optimum portability, however, take-down at locations other than at specified flanged valves is permitted by heating and breaking brazed joints and brazing on reassembly. Where this is impractical due to space limitations, take-down joints are provided. 276. Cutting All tube ends should be cut with a hacksaw or a metal cutting handsaw. Wheel cutters are not satisfactory for cutting tube ends that are to be brazed into bored fittings. Either the cutter or the roller usually deforms the tube ends so that it is impossible to get the proper fit between the tube and fitting bore. All tube ends should be cut square so that, when inserted into the fitting, the ends of the tubing will rest squarely against the shoulder or the stop in the fitting outlet. All burrs should be removed by reaming or filing. 277. Sizing All tube ends should be seized to provide clearances between the inside surface of the fitting and the outside surface of the tubing. When the tubing is moved by hand in any direction in the fitting, the maximum clearance at any location, determined by a feeler gage, should not exceed these clearances. Sometimes the tube ends become enlarged during the bending process. In other cases, the ends can be AGO 6244A considerably undersized due to bending, clamping, or similar operations. In these instances, it will be necessary to correct the dimensions to obtain a proper fit between component surfaces. To increase the clearance, the ends will have to be filed to fit; to decrease the clearance, the ends will require expanding. On sizes 2 inches ID and smaller, a drift pin or plug, similar to that shown in figure 237, should be used to increase the end diameter. On sizes over 2 inches ID, a sizing jig, as shown in figure 238 should be used. To use this type of jig, SILVER BRAZE HARDEN GRIND AND POLISH (TOOL STEEL) Figure 237. Shaping and sizing tool for tubing not over 2 inches ID. 5/8 IN_ DIA Figure 238. Shaping and sizing tool for tubing over 2 inches ID. the tube ends are clamped in the jig, which is held in a vise. A ball-peen hammer is then used to round up the tubing and to stretch it to the proper size by hammering on the inside of the tubing. 278. Flange Joints Flanges are installed in piping systems for ready removal of piping in order to provide for portability of machinery and equipment, accessibility to equipment, and convenience in main- GASKET ""LXXXX!....,....,..........-....FNVS2SI..,....,........,OT"""--------.NSXXJ.,..........,.....,-__,..!Xo:rx"'"~"/'""'Z'""'Z.--Zr-zn..-~r-------.:rr./r.zr-zrzr-/rz'71J LOW PRESSURE TYPE WITH RING GASKET HIGH PRESSURE TYPE VAN STONE OR LAPPED WELDING NECK FLANGE, BUTT-WELDED TO TUBE SLIP-ON FLANGE, WELDED FRONT AND BACK Figure 239. Types of flange joints. AGO 5244A 299 tenance. The-material and design of a flange are determined by\ 'its intended service. Figure 239 shows different types of flange joints installed in piping systems. 279. Mountings Flanges are connected to pipe and tubing by brazing for nonferrous material and by welding for ferrous material. Figures 240 and 241 show typical procedures for mounting slip-on flanges and for mounting welding neck flanges on pipe or tubing. TYPICAL SLIP-ON FLANGE WELD Figure 240. Methods for mounting slip-on flanges. 280. Flange Face Surface Finish A fine tool finish is normally required on nonferrous flanges and on steel flanges in low pressure service. Steel flanges in high pressure systems are given a serrated or a phonographic finish. The majority of vessels built after 1959 have flanges with surfaces finished as described above. In 1959, the standards for flange face surface finishes were revised to provide the following: a. Nonferrous and Ferrous Flanges for Use w-ith Sheet Gaskets. These flanges are of a nominal size of 12 inches or less with concentric serrated or phonographic finishes from 63 to 500 rough height rating produced by machining BACKING RING SHALL BE MACHINED FLUSH WITH INSIDE DIAMETER OF PIPING ENING IH BACKRIHG SHALL HOT EXCEED 1/16·11'1. TYPICAL GROOVED BUTT JOINT, WELDED ON REMOVABLE RING ROOT OPENING TYPICAL GROOVED BUTT JOINT, WELDED BOTH SIDES Figure 241. Methods for mounting welding neck flanges. cuts from 0.002 to 0.010 inch in depth in the range from 30 to 80 serrations per inch of fr.ce width. The tips of the serrations should not exceed 0.010 inch in width. For flanges over a nominal size of 12 inches, the requirements should be the same, except that from 21 to 80 serrations per inch of face width can be used. Figure 242 illustrates different types of sheet gaskets. b. Flanges for 0-Ring Seals. A finish of 63 rough height rating is the maximum limitation for 0-ring grooves. A finish of 125 rough high rating is the maximum limitation on the fl~:mge face opposite the groove. c. FeTrous Flanges for Spiral-Wound Gaskets. A finish with a circular lay, concentric or phonographic, leaving a roughness not exceeding 500 rough height rating is produced by machining cuts of 0.003-inch maximum depth with not less than 32 cuts per inch of face width. For special installation involving radioactive service or hazardous fluids, which are either toxic or explosive and where a finer finish is required, the requirement should be the same, except the finish should be 125 rough height rating maximum. For flanges where the flange AGO 5244A 0 ~ ~ SHEET ASBESTOS GASKETS FLAT RING GASKET FLAT FULL-FACE GASKET Figure 242. Flat gasket shape.q. face cannot be turned and tool marks run across the flange face, the surface finish should have a maximum rough height rating~of 125. 281. Repair to Gasketed Joints The following instructions should be followed in accomplishing repairs to gasketed joints: a. All sealing and bearing surfaces must be cleaned thoroughly. Surfaces should be checked for signs of damage from erosion or steam cutting. Flanges showing damage should be refaced or replaced. b. Gaskets showing imperfections, such as brittleness of rubber gaskets, cuts, or wire drawing permanent set, indicated by deep impressions in gasket material from flange faces, must be replaced. Similarly, bolts and nuts that show signs of corrosion or other damaging imperfections should be replaced. c. Gaskets removed from joints in fuel systems should be discarded. Note. If leakage continues after these instructions are followed and approved gasket materials are used in flanged joints, an investigation for other possible causes, such as misalinement or uneven flange faces, should be made. If unsatisfactory conditions still con tinue, a report should be made and submitted to the proper repair activity. 282. Bolting Joints in Piping Systems a. Gasket Materials. Gasket materials are designated for a definite bolt loading in order to yield properly and result in a tight joint. Gasket materials are softer than flange face materials to preserve the flang~es. Gaskets are divided into two general categories according to material (fig. 243): soft materials such as sheet rubber and sheet asbestos over 1/8 inch thick and hard materials such as spiral-wound, metallic asbestos and sheet asbestos less than % inch thick. (1) Soft mate1·ials. Flange joints utilizing soft gasket materials can be tightened with open-end or other standard wrenches using reasonable force without danger of overstressing the bolts or distorting the flange. Caution: Care must be taken not to overcompass soft gasket materials, as permanent set and loss of resiliency can result, causing gasket failure after a short period of operation. (2) Hard mater"ials. With hard gasket materials, it is important to tighten each bolt to a specified torque so that the bolt strength will be adequate while operating at higher temperatures. The most critical gasket in this category is the spiral-wound, metallic-asbestos gasket, which is used for high temperature and pressure applications. b. Spiral-Wound, Metallic-Asbestos Gaskets. Spiral-wound, metallic-asbestos gaskets are AGO 5244A RINGS RUBBER-CORED, DUCK-WRAPPED, WIRE-INSERTED ASBESTOS BRAIDED COPPER PRESSED COTTON FABRIC GRAPHITE LUBRICATED COILS SPIRAL HIGH PRESSURE ROD, GRAPHITEASBESTOS CLOTH AND BRAIDED FLAX RESILIENT RUBBER LUBRICATED ASBESTOS MOLDED RINGS EXPANSION JOINT PACKINGS ASBESTOS, ALUMINUM, GRAPHITE, AND WIRE-INSERTED BRAIDED ASBESTOS, NEOPRENE COMPOUNDS GRAPHITE-LUBRICATED Figure 243. Packing materials. composed of interlocked piles, spirally wound, of preformed, corrugated metal and asbestos strips, called a FILLER, and a solid metal outer or centering ring, sometimes called a RETAINING R!NG. Previously, specifications covering military gaskets of this type specified a retaining ring thickness of %2 inch in order to conform with commercial-type gaskets. A survey to determine the most desirable retaining ring thickness for both military and commercial flanges led to the standardization of the %-inch thick retaining ring presently specified. The filler is replaceable. When replacement of a gasket is required, the filler should be removed from the retaining ring and replaced with a new refill. The retaining ring need not be replaced unless it is damaged. (1) Application. Spiral-wound, metallicasbestos gaskets are used for valve bonnets, manhole cov,ers, and similar special applications in addition to piping line joints. Gasket filler thickness has been standardized at 0.175 ±0.005 inch; a thickness of 0.125 ±0.005 inch can be used where required by flange design considerations. (2) Installation. Spiral-wound, metallic-asbestos gaskets are designed to be installed at a compressed thickness of 0.130 ±0.005 inch. This corresponds to a flange/bolt stress, based upon the cross sectioned area at the thread root, as follows: AGO 5244A (a) Gaskets per Military Specification MIL-G-16265: For 150 psi flanges __________________________________30,000 psi ± 10 percent (all sizes). For 300, 400, and 600 psi flanges: %,-inch to l-inch ________________________________25,000 psi + 10 IPS and 16-inch OD piping. percent. 11,4-inch to 12-inch ______________________________ 30,000 psi ± 10 IPS and 14-inch to 15-inch OD piping. percent. (b) Gaskets per Military Specification MIL-G-21032: For 150, 300, 400, 600, 900, and 1500 psi flanges: 1,4-inch to l-inch IPS______________________________25;ooo psi ±10 p1pmg. percent. 11,4-inch IPS and larger ___________________________ 30,000 psi ±10 ptpmg. percent. For 2500 psi flanges __________________________________25,000 psi ±10 percent (all sizes). c. Bolt Stress. (2) The bolt stress to be applied in the assembly of flanged joints has been (1) Table XXI shows typical stretch of selected to provide a reasonable factorbolting materials under various load of safety based on the yield point ings at about 70°F. (21.1 °C.). of the bolting material and, at the Table XXI. Bolting Material Stretch same time, to insure a tight joint. The approximate torque required to obtain Stress based on cross sectional Stretch of effective area at root diameter of thread length (inches the stress indicated for various size (pounds per square inch) per inch) alloy-steel bolts and studs is shown in table XXII. 1,000 0.000033 20,000 0.000660 Caution: Factors to be considered 25,000 0.000833 in assembling flanged joints ?.,re well 30,000 0.001000 lubricated threads, excess bolting on 40,000 0.001320 45,000 0.001485 flanges 11;2-inches IPS and below in size, and limited gasket seating area. Note. The effective length of bolting is considered Extreme care must be exercised in to be the distance between the centers of the nuts. This assembling such joints to avoid dam is shown in figure 244. age to the gasket or the flange. Table XXII. Torque Values f-BOLT-STUD LENGTH -l Nominal size Approximate Approximate I of alloy steel torque to obtain torque to obtain I I bolt or stud 30,000-psi stress 25,000-psi stress (inches) (foot-pounds) (foot-pounds) % ______ 30______ 25 60______ %----~-50 %, ______ 100______ 83 %______ 160 ______ 133 245______ 1 ------205 355______ 11h ------295 500______ 114------416 13,-B ______ 645______ 567 1% ______ 800 ______ 667 Figure 244. Bolt steel measurement. AGO 5244A ( 3) Torque wrenches should be used to apply the initial required bolt stress. When torque wrenches are used, the values listed in table XXII should be applied to obtain the required stress. The stress of the bolts must be check<.-n (2c) for pipes of different sizes and for fittings of 45° and 60°. · Table XXIII. Deductions for Use with Off.~et Chart Pipe Size 14------------ %_____________ 1h ------------ !)4 ------------ 1 _____________ _ 11A, ----------- 1%----------- 2 ________ _, _____ 2%------------ Deduction (inches) 46" elbows !)4 ________ rs ________ !)4 ------ % _______ % _______ 11,4______ 1% ______ 1 % ______ 2_________ 60" elbows 1 1 1% Ph 1% 214 2% (3) Example 1. What length (1) of 2inch pipe is required for an offset, usin_g 60° elbows, if the amount of offset (a) is 3 feet 6 inches? Solution. Opposite 3 feet 6 inches on the_ (a) scare in the offset chart (fig. 252), the value of (b,) is found to be 4 feet % inches on the outside scale. The deduction (2c) for a 2-inch pipe with 60° elbows is 21,4 inches, from table 23. Hence, the length of pipe required is ( 1) :::::: 4 feet % inches minus 21;4 inches 3 feet 10%, inches. Pipe Size 3 _____________ _ 3%----------- 4 _____________ _ 5 _____________ _ 6 _____________ _ 8 _____________ _ 10_____________ 12 ____________ _ Deduction (inches) 45° elbows 60" elbows 2% ______ 3 2% 3 _______ _ 3!)4 3% _____ _ 4% 414------5% 5% ______ 9% 7l,.fl_ _____ 9% 8% (4) Example 2. An offset of 5 feet 11 inches is made with 45° elbows in a line of 6-inch pipe. What length (1) of pipe should be cut? Solution. Opposite 5 feet 11 inches on the (a) scale in the chart (fig. 252), the corresponding reading on the inside scale is 8 feet 4% inches, which is the distance (b.). From table XXIII, the deduction for a 6-inch pipe . with 45° elbows is 41;4 inches, which is the value (2c). Hence, (1) = 8 feet 4% inches minus 4% inches = 8 feet 1fs inches. Section VI. REPAIR OF PIPING 296. General The repairs of p1pmg systems on vessels sometimes consist of a simple procedure involving nothing more than the renewal of a composition seat in a water tap or the replacement of a worn or blown flange gasket. In other cases, however, the repairs to piping systems are much more complex and involve taking down sections of the system and fabricating and installing entire assemblies or subassemblies. a. Continuing Leakage, Breakage, or Failure. When continuing or repeated leakage, breakage, or failure occurs in a piping system, the cause should be determined and corrected. Common causes are as follows: ( 1) Misalinement. (2) Inadequate allowance for thermal expansion, working of the vessel, and other movements. (3) Vibration. (4) Hydraulic ram. (5) Rapid temperature changes. AGO 5244A (6) Galvanic corrosion. (7) Erosion. b. Precautions for Repair of Piping. Prior to repairing valves or piping, the following precautions should be adhered to. (1) Before breaking a line or valve bonnet joint, or cuting into a line, insure that the following are accomplished: (a) Valves isolating the section are closed and secured in such a manner that they cannot be opened accidentally, either locally or remotely. Insure that the valves are locked or wired closed and a warning tag attached. (b) The line is completely drained and there is no pressure on the line. (c) Precautions are taken to prevent fire or explosion from flammable liquids and vapors. (d) Adequate ventilation is provided. (e) In breaking flanged joints, two diametrically opposite securing nuts remain tight while the remaining nuts are slackened. Then slacken these two securing nuts sufficiently to permit breaking the joint. After joint is broken and line or valve is proved to be clear, remove all nuts. (2) Before working on any piping system, a survey should be made to insure that under no condition can any liquids splash on exposed electrical equipment. If there is any possibility of splashing a switchboard or other electrical equipment, the following precautions will be adhered to. · (a) Deenergize electrical equipment and cover with a waterproof material. (b) Cover electrical equipment completely with a rubber sheet or other nonconductive waterproof material if it is not possible to deenergize the equipment before work on the piping system begins. Do not restrict ventilation to the point that equipment will overheat. (3) Open piping, prior to repairing valves or piping, away from electrical equipment at a lower level if feasible, to insure that the line is completely drained and unpressurized. c. Reshaping of Dented Copper Piping. Copper piping sections that have been dented, flattened, or distorted can be brought back to normal roundness and shape by the following method. Anneal the entire section or, if preferred, the damaged section. Place under hydrostatic pressure not exceeding the test pressure of the system. While under pressure, hammer the piping, beginning with the high spots, until proper roundness is attained. This method has the advantage of eliminating hammering on a ball or shape and can be employed on large seamed piping. d. Repa·iring Thread Leaks. Leaking threaded joints, which cannot be tightened with a reasonable amount of pullup, should be taken apart and cleaned. The joints should be examined for damaged threads, recoated with a compound suitable for the intended service, and reassembled with care to avoid any further thread damage. Poorly cut threads are a constant source of trouble with threaded joints; therefore, it is essential that pipe thread cutters be properly used and cared for. Table XXIV lists various causes of troubles for pipe thread cutters and the corrective measures to be taken. Table XXIV. Troubleshooting Chart for Pipe Thread Cutte1·s Trouble Probable Cause Rough threads ------------------Dull chasers ---------------------Insufficient lubrication ____________ Improper lead shape ______________ Excessive or insufficient lead cutting angle. Broken tooth in chaser leader ______ Remedy Sharpen chasers. Apply plenty of good oil. Grind correctly. Grind to correct angle. Grind out entire tooth. AGO 5244A Trouble Probable Cause Remedy Chaser not set to form true cutting Clean slots; set chasers to true cutcircle. ting circle; grind chasers, if necessary, to uniform length. Shaved threads Improper lead of chaser ___________ Regrind lead. Chasers not tracking properly _____ Clean and lubricate slots. Chasers not set in correct rotation _ Correct chaser setting. Carriage travel retarded (machine Repair carriage. only). Wavy threads -------------------Die or chasers not true (manual Center die or chasers. only). Loose chasers (machine) __________ Install new die head. Thumb screw not tight (manual Tighten with wrench. only). Worn cam in head (machine) _______ Install new die head. Wornout lead screws (manual only) __ Get new die stock. Cuttings or dirt in chaser slots Clean chaser slots. (manual only) .. Shoulder burrs __________________ Pipe ends not square (manual) ______ Recut pipe square and rethread bad thread. Die and chuck not alined (machine)__ Check and realine. 297. Temporary or Emergency Repairs Chapter 3 of this manual describes various pipe repair methods for damage control purposes. These methods can be used for making temporary or emergency repairs to piping. a. Small holes can be repaired by drilling and inserting a rivet or through-bolt or by drilling (and threading if necessary) and inserting a screw. b. Larger openings can be closed by placing a suitable gasket or soft patch over the opening and holding the gasket in place by means of the following: (1) Serving with marline wire. (2) Metal straps. (3) Sheet metal collar, similar to a hose clamp, secured with nuts and bolts. Note. Preferably, the gasket should be of the same material used for line-flange gaskets. A suitable sealing compound can be applied between the gasket and pipe to assist in obtaining a tight joint. c. The Emergency Damage Control Metallic Pipe Repair Kit contains materials and instructions for repair of low temperature piping with plastic resins. Repair by this method requires about 30 minutes in order to permit curing of the plastic. 298. Semipermanent Repairs a. The piping can be served with wire drawn on tightly and soldered or· brazed as it is applied. Several layers of wire securely bonded give a strong, tight repair. b. A casting of soft metal can be formed around the piping. The section of piping should be removed and the leaks stopped with soft solder. The piping should be placed in a vertical position and filled with water above the level of the leaks. A sheet metal mold made tight with fire clay should be placed completely around the piping at the leaks, and a molten mixture of available soft metals, such as lead, babbitt, or zinc, poured into the mold. The piping must be filled with water to prevent the piping f11om expanding when heated by the casting, then the casting is pulled away from the piping when contracting during cooling. 299. Permanent Repairs a. Small leaks in copper or brass piping should be closed by brazing. b. Large leaks in copper or brass piping can be closed by brazing a patch over the leak as follows: (1) Shape a copper patch of suitable thickness and size to the part of the piping requiring repair. AGO 5244A (2) Clean thoroughly the surfaces to be the new section, however, should be the same as brazed together with a file or emery that used in the remainder of the system. cloth, and coat with flux. (3) Wire or clamp the patch securely in place. ( 4) Build screening walls with firebrick, sheet asbestos, or similar material to confine the heat to the vicinity of the area to be brazed. (5) Apply heat with acetylene torch, a forge fire of charcoal or coke, or oil flame. Caution: If an oil flame must be used, take extreme care that the oil is perfectly atomized, as the slightest deposit of oil on the surfaces to be brazed will spoil the work. Do not burn the piping. (6) Feed brazing alloy between the surfaces to be brazed, as the melting of the brazing alloy progresses until it has run between all parts of the patch. The brazing alloy is applied from the inside or outside of the piping, depending upon the circumstances. Arrange to cool the work slowly, using the torch if necessary. c. When repairing leaks by welding, the procedures should be in accordance with those applying to the joining of new piping by welding. 300. Renewing Piping When replacement of a section of piping is required, the procedure for installation of the new section should be in accordance with the applicable maintenance manual pertaining to the installation of new piping. The material of 301. Testing Repaired Piping a. Piping or piping assemblies, except Freonrefrigerant piping, removed for repair or renewal should be tested hydrostatically before reinstallation at a pressure 50 percent above the maximum allowable working pressure, but in no case less than 50 psi gage. This pressure should be held while a complete inspection is made of the pipe assembly, with special attention given to the renewed parts. The pressure for this inspection for evidence of slow leaks will be held for at least 15 minutes. When porosity is suspected, the pressure will be held until the inspector is satisfied that no slow leaks exist. An air or gas test, subsequent to the hydrostatic test, will not be required due to the danger involved. When required to make a specified air test, personnel will observe all safety precautions. b. Where shipboard welds are required for replacement of piping or other repair, the welds will be checked in accordance with procedures given for the applicable class of pressure piping. If a repaired portion of a system is reinstalled by shipboard welds and the arrangements or circumstances prevent the use of radiography, a hydrostatic test of 150 percent psig will be applied to the system affected by the welds. This will be in addition to the other nondestructive tests. All repairs to systems operating normally under vacuum or atmospheric conditions will be tested for leakage during normal service. When a repaired portion of the system can be isolated, only that portion need be tested. Section VII. VALVES 302. General Every piping system must have some means of controlling the amount and direction of the flow of liquid or gas through the lines. This is accomplished by the installation of valves which can be opened or closed as required. Valves are usually made of bronze, brass, cast or malleable iron, or steel. Steel valves are either cast or forged and are made of either plain steel or alloy steel. Alloy steel valves are used in high pressure, high temperature systems. The disks and seats of these valves are usually surfaced with a chromium-cobalt alloy known as stellite. This material is extremely hard. Brass and bronze valves are used mostly where temperatures do not exceed 550°F. (288°C.). Steel valves are used for all services above 550°F. (288°C.) and in lower temperature systems where internal or external conditions of high pressure, vibration, or shock AGO 5244A 115 would be too severe for valves made of brass or iron. Bronze valves are used almost exclusively in systems carrying salt water. The seats and disks of these valves are usually made of brass, a metal which is both corrosion resistant and erosion resistant. a. Common Types of Valves. Many different types of valves are used to control the flow of liquids and gases. Basically, there are two main groups of valves: stop valves and check valves. Stop valves are those which are used to shut off or, in some cases, partially shut off the flow of fluid. These valves are controlled entirely by the movement of the valve stem. Check valves are used to permit the flow of fluid in only one direction. These valves are controlled by the movement of the fluid itself. Valve designs vary greatly, due to the varying demands of service. BODY BONNET BOLT There are also some valves which are combinations of these basic types; others, such as reducing valves, must be considered as special valves, bearing only slight resemblance to the basic types. In general, the more common types of valves used in marine piping systems are gate, globe, plug or ball, butterfly, check, and relief valves. (1) Gate valves. Gate valves are used in systems where a straight flow with a minimum amount of restriction is desired; frequent use of them is made in water lines. Most gate valves have a wedge-shaped gate, although some have a gate of uniform thickness. The gate is connected to the valve stem and is positioned by a handwheel. The port is the full size of the pipe and DISK STEM RING GATE VALVE (RISING STEM) GLOBE VALVE Figure 253. Gate and globe val·ves. AGO 5244A extends straight through the valve. A cross section of a gate valve is shown in figure 253. Some types of gate valves have a rising stem, and a glance at the valve will show whether it is opened or closed. In the type of gate valve with the nonrising stem, the stem revolves in the bonnet, and the gate is raised or lowered by the threads on the internal end of the stem. On this type of valve, a pointer or gage is usually installed to indicate opened and closed posi,tions. Unlike most valves, gate valves will operate properly with either face on the inlet side, thus simplifying the job of installation. Cast or forged steel valves have disks and seats made of nickelcopper alloy, chromium steel, or a steel that has been treated with a hard facing material. Valve stems are of corrosion-resistant steel, and the handwheels are of fabricated steel, brass, or aluminum. Bronze gate valves are made entirely of bronze, except for malleable iron or aluminum handwheels. (2) Globe val,ves. Globe valves (fig. 253) are so named because of the globular shape of their bodies. It should be noted, however, that other types of valves can also have globe-shaped bodies; hence, the name is not always properly descriptive. In a globe-type stop valve, the disk, which is attached t0 the valve stem, seats against a seating ring or seating surface and thus shuts off the flow of fluid. When the disk is moved off its seat, fluid can pass through the valve. Globe valves can be used partially· open as well as fully open or fully closed. Globe valve inlet and outlet openings are arranged in several ways and are used to suit the requirements of flow. Figure 254 shows three common types of globe valve bodies. In the straight type, the fluid inlet and outlet openings are in line with each other. In the angle type, the inlet and outlet openings are at an angle to each other. An angle type globe valve is used where a stop valve is needed at a 90-degree turn in a line. The cross-type: globe valve has three openings, rather than two; it is frequently used with bypass piping. . (3) Plug or ball valves. Figure 255 illustrates two variations of the plug-type stop valve. Essentially, a plug valve consists of a solid cylindrical or truncated cone-shaped plug which is free to turn about its axis within a closely fitting hollow cylinder. A passage is bored through the plug at right angles to its axis. When the plug is turned so that its passage is alined with ports in the cylinder wall, passage is effected from the inlet port to the outlet port. Turning the plug 90 degrees about its axis from this position results in closing the ports. Other variations of .the plug valve are three-way and four-way valves by which the routing of the fluid can be selected. Ball valves are similar to plug valves except that a ball is used to control the liquid flow instead of a plug. (4) Butterfly valves. Although the design and construction of butterfly valves can vary somewhat, a butterfly-type disk and some means of sealing are common to all butterfly-type valves. The butterfly valve illustrated in figure 256, although relatively new in CROSS ANGLE STRAIGHT Figure 254. Types of globe valve bodies. AGO 52~4A service, has some advantages over gate and globe valves in certain applications. The butterfly valve is light in weight, takes up less space than a gate valve or globe valve, is easy to overhaul, and is relatively quick acting. The butterfly valve consists of a body, resilient seat, butterfly-type disk, stem, packing, notched positioning plate, and handle. This valve provides a positive shut-off and can be used as a throttling valve set in any position from fully open to fully closed. The replaceable resilient seat is held firmly in place by mechanical means; NONLUBRICATED VALVE neither bonding nor cementing is necessary. It is not necessary to grind, lap, or do machine work to replace the valve seat; therefore, overhaul of the valve is relatively simple. The resilient seat is under compression when it is mounted in the valve body. This forms a seal around the periphery of the disk and around both upper and lower points where the stem passes through the seat. Packing is provided to form a positive seal around the stem in the event that the seal formed by the seat becomes damaged. When closing the valve, the handle needs only to be CLOSED VALVE LUBRICATED VALVE Figure 255. Plug valves. AGO 5244A turned a quarter of a turn to rotate the disk 90 degrees. The resilient seat exerts positive pressure against the disk, assuring a tight shut-off. Butterfly valves can be designed to meet a wide variety of applications. The classes of butterfly valves used for various services are indicated in the following list: CLASS A-Fresh water and sea water. Series 50 -50 psi maximum working pres sure (22 inches IPS and above). Series 150-150 psi maximum working pres sure (20 inches IPS and below). Series 200 -200 psi maximum working pres sure (20 inches IPS and below). CLASS B-JP-5 Fuel. Series 150-150 psi maximum working pressure (20 inches IPS and below). CLASS C-Oil, fuel. Series 150-150 psi maximum working pressure (20 inches IPS and below). CLASS D-Oil, diesel or lubricating. Series 150-150 psi maximum working pressure (20 inches IPS and below). (5) Check valves. Check valves are designed o permit flow through a line in one direction only. They are used in drain lines; for example, where it is important that there be no reversal of flow. Considerable care must be taken to insure that valves of this type are properly installed. Most of them have an arrow or the word inlet cast on the valve body to indicate direction of flow. If a valve lacks any such indication, a close check must be made to insure that the flow of fluid in the system will operate the valve in the proper direction. The port in a check valve can be closed by a disk, a ball, or a plunger. The valve opens when the pressure on the inlet side is greater 1than that on the outlet side, and it closes when the reverse is true. All such valves open and close automatically. These valves are made with threaded, flanged, or union faces, with screwed or bolted caps, and for specific pressure ranges. (a) The disk of a swing-check valve (fig. 257) is raised as soon as the line pressure of the fluid entering below the disk is of sufficient force. While the disk is raised, continuous flow takes place. If for any reason the flow is reversed or if back pressure builds up, this opposing pressure forces the disk to seat, thus stopping the flow. The operation of DISK NUT ARM Figure 256. Butterfly valve. Figure 257. Swing-check valve. AGO 5244A 319 a lift-check valve is similar to that of the swing-check valve, except that the valve disk moves in an upand-down direction instead of through on arc. This difference is illustrated in figure 227. (b) Some valves function either as stop valves or as check valves, depending upon the position of the valve stem. These valves are known as stop-check valves. Stop-check valves are shown in cross section in figure 258. This type of valve is similar in appearance to a lift-check valve; however, the valve stem is long enough so that when it is screwed all the way down it holds the disk firmly against the seat, thus preventing any flow of fluid. In this position, the valve acts as a stop valve. When the stem is raised, the disk can be opened by pressure on the inlet side. In this position, the valve acts as a check valve to allow the flow of fluid in only one direction. The amount of opening is controlled by the position of the valve stem, regulating the amount of fluid allowed to pass through the valve. A special type of stop-check valve is arranged so that the disk can be fully lifted when the valve stem is raised to its highest position. Thus, the valve acts as a stop valve when the stem is all the way down and as a check valve when the stem is partly raised, but allows the free flow of fluid in either direction when the stem is entirely raised. (6) Relief valves. Relief valves, or pressure-reducing valves, are automatic valves used to provide a steady pressure which is lower than the supply pressure. These valves can be set for any desired discharge pressure within the limits of the design of the valve. Of the various types of reducing valves found on vessels, the type installed in the flushing system is of primary interest. Most of these valves are of the single-seated, direct-acting, spring-loaded, diaphragm type as rTtT"'--"-GLAND BOLT HUT ~~--GLAND ~--GLAND BOLT ~-'of"+'---PACKING '!-+---BOHNET BOHNET STUD ~n,---RELEIF PLUG Figure 258. Stop-check valves. AGO 6244A shown in cross section in figure 259. Control of water passing through this valve is effected by means of a pressure difference on opposite sides of the diaphragm. The diaphragm is secured to the stem. Reduced water pressure at the valve outlet is led through an internal passage to a diaphragm chamber below the diaphragm. An adjusting spring acts on the upper side of the diaphragm. A leather cup washer or a neoprene 0-ring forms the water seal between the valve inlet and the diaphragm chamber. This seal is located about halfway down the valve stem. The amount of pressure applied by the water to the underside of the diaphragm varies according to the discharge pressure. When the discharge pressure is greater than the spring pressure, the diaphragm is forced up. Because this is an upward-seating valve, the upward movement of the stem tends to close the valve, or at least to decrease the amount of discharge. When the discharge pressure is less than the spring pressure, the diaphragm and the valve stem are forced down, opening the valve wider and increasing the amount · of discharge. When the discharge pressure is equal to the spring pressure, the . valve stem remains stationary, and there is no change in the flow cf water through the valve. The amount of pressure applied by the spring to the top of the diaphragm can be varied by turning an adjusting screw. Turning the adjusting screw clockwise increases the pressure applied by the spring to the top of the diaphragm, thus tending to open the valve. Turning the adjusting screw counterclockwise decreases the amount of spring pressure on the top of the diaphragm, thus tending to decrease the amount of discharge. Opening and closing of the valve will continue as long as the discharge pressure fluctuates. For example, when a water closet is flushed, the pressure drops in the sup- LOCKNUT PADLOCK SEAT RING DISK INSERT~~~~~~~ DISK BOTTOM COVER Figure 259. Relief valve. ply line:· This line is on the discharge .,,. side of the pressure-reducing valve, so the diaphragm moves down and opens the valve. As the flush valve closes, the pressure builds up again and closes the valve. b. Throttling Serm:ce in Valves. For severe throttling service, plug or needle-disk globe and angle valves are considered superior. Gate valves are never recommended for throttling. Ball and butterfly valves have fair throttling characteristics. c. Installing Valves. (1) The best position in which to install a valve is with the stem pointing straight up. When the stem points downward, the bonnet acts as a pocket for scale and other foreign matter in the line. Such matter can interfere with valve operation by cutting and eventually destroying inside stem threads. The recommended position AGO 5244A for double-disk gate valves is with stem upright. (2) In liquid lines subject to freezing temperatures, an upside-down position for valves is undesirable because liquid trapped in the bonnet can freeze and rupture it. Even when installed upright, valves in such lines should have drain plugs in the body as a precaution against freezing. (3) The proper method for installing a globe valve is determined by the purpose for which it is used. (a) In cases where flow should be continuous and no harm would come from the valve being open due to a detached disk, having the · pressure below the disk is advisable. (b) When damage would occur from having the disengaged disk blow open and leaving the globe valve wide open, it is advantageous to have the pressure above the disk. (c) The general rule should be that, unless otherwise required, a globe valve will give more satisfactory service when installed with pressure below the seat. This type of installation permits the replacement of the valve stem without isolating the entire system. · ( 4) Install all check valves so that the disk will open with the flow. To insure closing of the disk when back flow occurs, position of check valves in line must permit closure of disk by gravity. Caution: When a stop valve has been modified to a stop-check valve, a plate or disk should be inserted under the handwheel nut and marked: STOP-CHECK VALVE-CAUTION: INSTALL IN CORRECT DIRECTION. Failure to make such marking can result in installation of valve in reverse direction, causing possible damage or malfunction. d. Principal Difficulties Causing Valve Leakage. (1) Leakage through the valve is generally caused by failure of disk and seat to make a tight joint, and can result from the following: (a) Foreign substances, such as scale, dirt, waste, or heavy grease, lodged on the seat in such a way that the disk cannot be seated. If the obstructing material cannot be blown through, the valve will have to be opened and cleaned out. (b) Scores in seat or disk caused by attempting to close the valve on scale, dirt, or erosion. If the damage is slight, the valve can be made tight by grinding; if more extensive, the valve will have to be reseated and then ground. (c) Disk in a cocked position caused by feather guides fitting too tightly, by bent spindle guide, or by bent valve stem. (d) Valve body or disk too weak for the purpose used, permitting distortion of valve seat or disk under pressure. (e) Disk and/or seat not machined properly. (f) Leakage behind inserted seats. (g) Leaks through casting defects in valve disk or body, particularly in new valves. (h) Leakage past threads in seat ring. (2) Stuffing-box leaks can be remedied by setting up on the gland or repacking. The gland must not be set up or packed so tightly that the stem sticks. Persistent stuffing-box leaks generally are caused by a bent or scored valve stem. Considerable trouble with stuffing-box leaks can be avoided if valves are installed with the valve stem pointing upward. Before alerting the position of a valve stem, take the following into consideration: (a) The convenience in working, if an important valve. (b) Whether or not sufficient space is available to remove bonnet, stem, and disk. (3) Pressure-seal valves are assembled in the cold condition by the manufac- AGO 5244A turer. When steam is applied, expansion can take place in the bonnet joint so that leakage past the seal ring can occur. In order to prevent continued leakage and ste8.m cutting of the pressure-seal rings, the bonnets of all pressure-seal valves should be retightened after the valve has been brought up to operating temperature. Leakage through flanged or threaded bonnet joints should be repaired in the same manner that these joints are repaired in piping. (4) Sticking valve stems are caused by the following: (a) Stuffing-box set up or packed too tightly. To correct this fault, it is necessary only to slack up on gland and thus relieve packing pressure. (b) Stuffing-box gland cocked due to uneven setting up of gland nuts. Remedy by correcting position of nuts. (c) Paint or rust on valve stem which should be removed by cleaning. (d) Disk bound tightly to seat. caused by valve being jammed shut while hot, resulting in contraction from subsequent cooling. To relieve strain, carefully loosen yoke nuts; if not a yoke valve, slightly loosen bonnet nuts. This may free disk from seat. (e) Disk bound tightly to seat, caused by valve being jammed shut while cold, resulting in expansion from subsequent heating. Valve usually can be started with a wrench, taking ca~e not to spring the valve stem. If valve cannot be started, valve must be cooled and bonnet loosened to force disk from seat. (f) Valve open, caused by valve being jammed open while hot, resulting in contraction from subsequent cooling. Valve usually can be started with a wrench. If valve cannot be started in this manner, disassembly is necessary. (g) Valve open, caused by valve being jammed open while cold, resulting in expansion from subsequent heating. This condition is not serious, as the valve usually can be started by means of a wrench, and care is taken not to spring the valve stem. After opening a valve wide, it is good practice to turn the stem onehalf revolution in the closing direction, so that all danger of binding the valve will be eliminated. (h) Threads of stem burred from rough handling or upset by excessive pressure applied in attempting to move a stuck valve. This condition is the most serious of valve-stem troubles. If other measures to remove the stem fail, the bonnet must be removed, the stem must be cut out of the yoke or bonnet, and a new stem made. If the bonnet and yoke are damaged, they must be replaced. If the burred or upset threads of stem are found before they become stuck in the yoke or bonnet threads, they can be dressed smooth with a file or machined in a lathe. ( i) Bent valve stem. In this case, straighten or renew the damaged stem. (j) All important valves and all other valves that are likely to stick should be moved once a month or oftener, depending upon the frequency which experience indicates as necessary. (5) If a valve disk becomes loose from its stem, the .fault is due either to failure of the securing device or to corrosion through the stem. Failure of the securing device is infrequent in valves of good construction, and recurrence can be prevented by slight minor changes or by greater care in reassembling valve parts. Trouble due to corrosion is confined mostly to valves in salt water lines. Replacements should be made with rolled, Monel metal stems. Periodic inspections should be made of stems which previously have shown signs of corrosion, so that replacement can be made AGO 5244A 323 before failure occurs. In order to ( 1) Disks. Disks should be refaced in a prevent failure by corrosion, split pins lathe by machining and/or grinding. in valve disks in water lines should Insure that disks are properly cenbe of nickel-copper alloy instead of tered and have correct angles and diiron or steel. mensions. (6) Swing- and stop-check valves in main (2) Seats. Valve reseating machines and secondary drainage systems will should be used, when possible, to rebe dismantled and inspected annually face valve seats in place. These mafor cleanliness, freedom from foreign chines are available for most sizes matter, and integrity of valve seat. and varieties of both globe and gate valves. Insure that the proper size, seat angle, and abrasive are used. Use 303. Reseating Valves of these machines usually results in The depth of the defects in the seat and disk labor savings and avoids rewelding of determines the methods to be used for repair. welded-in valves. A cast-iron dummy Valve drawings should be referenced to obtain disk and grinding compound can also details on seat angles and dimensions. Technibe used to remove minor defects. The cal manuals for valve reseating machines disk must have the proper seat angleshould be consulted for operating instructions. and be remachined occasionally to In some cases, replacement of a valve can be maintain this angle and remove shoulmore economical and more desirable than re-· ders. A jig to guide and support this pair. When grinding seating surfaces, avoid dummy disk should be used. Seats of overheating to prevent changes in dimensions, valves removed for repair can be machanges in physical properties, and possible chined and/or ground by valve recracking after cooling. a. Very Minor Defects. If small leakage occurs and if there are no visible defects in the seat or disk and no working or other defects to prevent seating, the valve can be reseated by spotting in the seat and disk. The seat and disk are ground together with an abrasive such as grinding compound, powdered emery, or ground glass mixed with oil. The disk is turned back and forth on the seat. Occasionally the OUT OF ROUND STRINGY disk is lifted from its seat and its position is shifted slightly. Continue the grinding until a bearing all around is obtained. As a test of the work, put pencil marks at intervals of about l/2 inch on the bearing surface of the disk or seat. Drop disk on seat and rotate it about onequarter turn. If all the pencil marks rub off, the seating is satisfactory. For globe valves CORRECT with tapered seats and disks, remove only a minimum amount of metal, as this grinding operation reduces the effectiveness of the seal. The ability to seat property is reduced because the wedging action of the tapered faces is partially destroyed. b. Minor Defects. When defects do not reTOO WIDE TOO HIGH quire renewal of parts, the valves can be re seated as follows: Figure 260. Identification of spotted-in valve seats. AGO 5244A seating machines, lathes, or other suitable equipment. (3) Spotting-in. The method used to determine visually whether or not the seat and disk made good contact with each other is called SPOTTING-IN. To spot-in a valve seat, first apply a thin coating of Prussian blue evenly over entire machined face surface of disk. Then insert disk into valve and rotate it one-quarter turn, using a light downward pressure. The Prussian blue will adhere to valve seat at those points where disk makes contact. Figure 260 identifies a valve seat correctly spotted-in; it also identifies various types of imperfect seats. After noting the condition of seat surface, wipe all .Prussian blue off disk face surface. Apply a thin, even coat of Prussian blue to contact face of seat, and again place disk on valve seat and rotate disk one-quarter turn. Examine resulting blue ring on valve disk. The ring should be unbroken and of uniform width. If blue ring is broken in any way, disk is not fitted properly. ( 4) Gr-inding-1:n. The manual process used to remove small irregularities by grinding the contact surfaces of the seat and disk together is called GRINDING-IN. Grinding-in should not be confused with refacing processes in which lathes, valve reseting machines, or power grinders are used to recondition the seating surfaces. To grind-in a valve, first apply a small amount of grinding compound to face of disk; then insert disk into valve and move disk back and forth approximately one-quarter turn. Shift disk-seat relation from time to time so that disk will be moved gradually, in increments, through several rotations. During grinding process, grind ing compound will gradually be displaced from between seat and disk surfaces; therefore, it is necessary to stop every minute or so to replenish compound. Before applying new compound to disk face, wipe both the seat and disk clean. When it appears that irregularities have been removed, spot-in disk to seat as outlined in (3) above. Grinding is also used to followup all machining work on valve seats or disks. When the valve seat and disk are first spotted-in after they have been machined, the seat contact will be very narrow and will be located close to the bore. Grinding-in, using finer and finer compounds as work progresses, causes the seat contact to become broader. The contact area should be a perfect ring covering approximately one-third of the seatinO' b surface. A void overgrinding a valve seat or disk, as it tends to produce a groove in the seating surface of the disk; it also tends to round off the straight, angular surface of the disk. Machining is the only process by which overgrinding can be corrected. c. Major Defects. To avoid replacing complete valves in the event of major damage to the seating surfaces, the following procedure can be utilized: ( 1) Replace parts. Disks, seats, and inserts can be replaced in some valves. (2) Replace lost meted. Welding, plating, and metal spraying can be used to build up seating surfaces which have been eroded, scored, or otherwise damaged. This operation is followed by machining, grinding, and spotting-in. 304. Valve Repair Valve troubles, probable causes, and remedies are listed in table XXV for guidance. . Table XXV. Troubleshooting Chart for Valve Repair Troubie Probable cause Remedy Main valve fails to open when Lack of electrical power -----------With operating switch. closed, check operated electrically. for proper voltage to No. 1 solenoid. AGO 5244A :325 Table XXV. Troubleshooting Chart for Valve Repair-Continued Trouble Probable cause Remedy Solenoid fails to position pilot valve Check linkage for binding. properly. Burned out solenoid coil ----------- Check for visible evidence of burn. Check coil for direct shorts or breaks, using an ohmmeter. Stuck pilot valve ----------------- Attempt to turn pilot valve manually. If hard to turn, remove for repair. (If stuck pilot valve is not removed, solenoid cannot turn valve. This will cause solenoid to overheat and per haps burn out.) Plugged drain line ----------------- If main valve fails to open when pilot valve is properly positioned, inspect drain line to insure it is plugged. (Remember that fluid should dis charge from drain line each time main valve opens.) Main valve stuck closed ------------ Position control to open valve and re move tubing from the control to main valve cover; if main valve still fails to open, it must be disassem bled and freed. Ruptured diaphragm -------------- This condition will be apparent when valve is disassembled. Main valve opens slowly _________ Pilot valve partially stuck open _____ Check linkage for binding; try to turn pilot valve manually; if it turns hard, it must be removed for repair. Drain line partially plugged ________ Inspect drain line and remove obstruc tion. Main valve fails to close electrically Lack of electrical power ____________ Insure that proper voltage is being supplied to No.2 solenoid. Solei-wid fails to position pilot valve Check linkage for binding. properly. Burned out solenoid coil ____________ Check for visible evidence; check coil for direct shorts or breaks, using an ohmmeter; if necessary, replace coil. Stuck pilot valve ---~-------------- Turn pilot valve manually; if it is hard to turn, remove for repair. (Remember that a stuck pilot valve can cause solenoid to burn out.) Plugged supply line ---------------- Loosen pipe plug in top of main valve indicator, and, with pilot positioned to close main valve, watch for a steady flow. If flow stops, main valve inlet to pilot valve, tubing from pilot valve cover, or pilot valve itself is .plugged, and it will be nec essary to work back from main valve cover to locate point of stop page. Main valve fails when operated Any cause listed above, except Any remedy listed above, except manually. where electrical power is re where electrical power is required. qui red. AGO 5244A a. Packing Stuffing Box. The stuffing box is packed by placing successive turns of packing in the space around the rod of the valve stem. Where string packing is used, it is simply coiled around the rod, the ends being beveled to make a smooth seating for the bottom of the gland. The gland is then put on and set up by the bonnet nut or the gland bolts and nuts. To prevent string packing from folding back when the gland nut is tightened down, the packing should be wound to the right or in the same direction that the gland nut is turned. This will insure that there are no joints in the packing and reduce the possibility of leakage. Where successive rings are used, the ends of the rings should be cut square and even with ends butted to make a level joint. If rings are put in place by packing sticks, care should be taken to avoid splitting the packing. b. Repacking Valves Under Pressure. Certain types of gate, globe, angle, and stop-check valves, for some pressures, are designed to back-seat the stem against the valve bonnet when fully open. This allows the stem stuffing box to be repacked under pressure when necessary. In addition, high pressure valves usually have a pipe plug as a leak-off to the cooling chamber, and this pipe plug should be removed when repacking the valve under pressure. For valves where discharge cannot be permitted during replacing under pressure, the discharge will be blanked off securely before the valve is opened for the back-seating and repacking. c. Precautions for Installing and Operating Reducing and Regulating V al'ves. (1) Reducing valve installations should conform to the valve manufacturer's recommendations. In general, they Section VIII. 305. General From a thermodynamic standpoint, s,team can be considered as the carrier of thermal energy. In engineering installations, there are, broadly speaking, two major demands for heat: power generating equipment and heat transfer equipment. Both equipment installations are concerned with the problem of removing water condensation f:r;'om the steam without removing should be installed in a horizontal run of pipe with the superstructure in a vertical position. They should be located so that they are not in a piping pocket where water and dirt can accumulate. Also, their location should permit removal of the valve superstructure and working parts without removing the valve from the line. (2) Reducing valves have an arrow cast on the valve body to indicate the direction of flow through the valve. This marking should be observed when installing a valve to insure proper operation. ( 3) Each steam-reducing station should consist of an inlet cutout valve, a steam strainer, a reducing valve, a tapered increaser, and an outlet cutout valve. Bypassing these components should be a line containing a cutout valve and a throttling valve. On the discharge of the reducing station, a pressure-relief valve and a pressure gage should be provided. On some installations of reducing valves in parallel, only one bypass line, pressure gage, and relief valve are provided. ( 4) Reducing valves must be warmed up and drained before they are adjusted. ( 5) Cutout valves in the inlet and outlet lines of a reducing station should be fully open when the reducing station is in use. ( 6) Reducing station relief valves must be kept in good operating condition. They should be lifted by hand weekly. STEAM TRAPS any of the steam. Relatively large amounts of water in steam pipes result in a water hammer, endangering the piping and fittings. Water carried over with the steam into the power generating equipment can, in the case of reciprocating engines, cause cracked cylinder heads or, in the case of turbine installation, result in damaged blades. In heat transfer equipment, it is desirable to remove the water as it is con- AGO 5244A TRAP COLD-VALVE OPEN TRAP HOT-VALVE CLOSED Figure 261. Thermostatic steam trap. densed from steam, in order to increase the rate of heat transfer. In any case, it is desirable to remove the water without losing any of the steam, which is the thermal energy carrier. The device used to accomplish this is the steam trap or drain regulator. 306. Types of Steam Traps a. Thermostatic Traps. Operation of this trap is controlled by expansion of vapor from a volatile liquid inclosed in a bellows-type element. These traps are limited to pressures up to 100 psig. They are satisfactory for use in draining the constant-service steam system; intermittentservice steam system (except ventilation preheater), auxiliary exhaust system, and some oilheating steam systems. Figure 261 shows a typical thermostatic steam trap. This type of trap is lightweight, is compact, and requires as much as 40°F. ( 4.4 °C.) temperature differential to operate, depending upon the class of trap. In most instances, a cooling leg of bare pipe is provided between the trap and the unit Figure 262. Hucket-type steam trap. drained to facilitate drainage. b. Open-Bucket, Inverted-Bucket, and Ballr Float Traps. Operation of these traps is reguThey are satisfactory for use in draining the lated by the condensate level in the trap body. constant-service steam system and intermittentTheir use is limited to pressures up to 150 psig. service steam system (except fuel-oil service AGO 5244A VALVE CLOSED -MAIN FLOW SHUT OFF VALVE OPEN-MAIN FLOW THROUGH SEAT Figure 263. Thermodynamic-type pulsating continuous-flow steam trap. heater). Figure 262 shows a typical bucket-type steam trap. These traps are generally heavier and require more space than the thermostatictype traps. c. Pulsating Continuous-Flow Traps. There are two general types of pulsating continuousflow traps used in steam-drain collecting systems aboard floating craft: the thermodynamic, or impulse type, and the bimetallic-element type. (1) Operation of the thermodynamic-type trap is based upon principles governing the flow of fluids through orifices in series. Because of this, its use is limited to services where the back pressure on the trap is not more than 25 percent of the trap inlet pressure. There is a small amount of steam leakage through this trap when no condensate is present, which would be the case when underway with steam flowing and the steam lines drained. It is impossible then, to build up pressure in the drain-collecting system under this condition. If this condition occurs, certain nonvital traps should be secured to limit the drain-system pressure. Figure 263 shows a typical thermodynamic-type pulsating continuous-flow steam trap. (2) In the case of the bimetallic-element type trap, the fluid temperature acts on the element and either closes the trap when steam is present or permits the top trap valve to open if condensate is present. These traps are used primarily for draining main and auxiliary s,team lines, but they can be used in other services, under the proper conditions. d. Cont,inuous-fiow Traps. This type of trap has no parts and consists of fixed orifices in series. Because of this, it cannot adjust itself to a widely changing rate of condensate formation. Its use is restricted to services where the condensate rate is relatively constant such as in ventilation preheaters, constant-service steam systems, oil-heating steam systems, and whistlejacket drainage. It must not be used for services where condensate formation is not continuous. 307. Causes of Inefficient Operation of Traps The principal troubles, causes, and remedies of trap operation are shown in table XXVI. Table XXVI. Troubleshooting Chart for Operation of Traps Trouble Probable cause Remedy Discharge valve leaking _________ Scored by erosion or scale and dirt _ Reseat. AGO 5244A 329 Trouble Probable cause Remedy Leaking float or bucket __________ Trap is nonoperational ----------- Trap not operating properly ______ Valve does not seat properly _____ Line stoppage ------------------- Inverted bucket trap does not close_ 308. Positive Test For Traps Punctured float or bucket _________ Working parts adrift _____________ Discharge valve too small _________ Malfunctioning pump ______________ Internal load of valve exceeds pulling power of pump. Sediment in bottom of trap ________ Dirt or scale caught under valve ____ Excess air in lines (air lock) _______ Lack of proper amount of water ____ Repair leak. Secure parts in place with additional devices to prevent repetition. Replace valve or trap with one of larger capacity. Repair or replace pump. Adjust pump leverage. Blow out, if so fitted; otherwise, disassemble and clean trap. Operate handtripping device to dislodge dirt, or disassemble and clean trap. Open air cocks in lines. Shut valve on discharge side of trap and allow to fill with water. Fill trap by pouring water through inlet connection. On many vessels in service, steam traps, other than the thermostatic type, are fitted with a small atmospheric test valve installed in the discharge line between the trap and the trap discharge-cutout valve. This test valve is used to check the condition of the steam trap and the trap cutout valves. To test, close the discharge-cutout valve and open the test valve. If fitted to do so, trip the trap; otherwise, wait until it dumps and note if it shuts off properly. Some steam will accompany the discharged condensate due to reevaporation of a portion of the condensate at a temperature of 212°F. (100°C.) and atmospheric pressure. After the trap shuts off, a sizzle of steam denotes a leak. Thermodynamic or impulse-type traps require from 3 to 5 percent of full condensate capacity to prevent discharge of live steam. Should the discharge-cutout valve leak, a false test result will be given if the drain line is under steam pressure. To determine the source of leakage, close trap inlet-cutout valve. Ifsizzle stops, trap is leaking; if it continues, discharge-cutout valve is leaking. The presence of a defective trap will be made evident by an increase in the drain system pressure above the normal figure. When this occurs, the trap can be located by securing traps, one at a time, until the drain system pressure drops. When the trap is removed for repair, the condition of the trapcutout valves can be noted. If overhaul is indicated, this fact can be recorded for accomplishment when the drain system is secured. Section IX. STRAINERS, SEPARATORS, AND FILTERS 309. General Strainers are located in all piping lines to prevent the passage of foreign matter. They must be installed so that flow will be through the strainer element. Figure 264 shows a typical basket-type strainer. In some locations, duplextype strainers are used so that the flow of fluid through the system need not be interrupted when one element is removed for cleaning. Figure 265 shows a typical duplex-type strainer. 310. Cleaning Strainers a. To clean a strainer that has no air-cock vent in its top or cover, close valves leading to it; open strainer cover gradually, so that oil or any other foreign matter will not be sprayed out if strainer is air bound. Clean basket, replace, and secure cover. The strainer is ready for use when valves are opened. b. To clean a strainer fitted with a drain in the bottom and a vent in the top or cover, open AGO 5244A STRONGBACK COVER BASKET HANDLE BASKET STRAINER TO PUMP SUCTION t Figure 264. Basket-type strainer. drain in bottom to allow oil and sludge to run down; open. vent cock in top of cover to purge chamber of air. Close drain before opening valves, and close vent after opening valves. Strainers without a drain in bottom and a vent in top of cover should have bosses welded or brazed on for drilling and tapping for these connections. c. If the removed basket is heavily incrusted with grease or other foreign matter, it can be cleaned easily with a steam jet or by boiling in a pot, using boiler compound. d.. Suctions to bilge and double bottoms have a fixed strainer at the open end of the pipip.g or over the drain well. Care must be taken to keep rags and other similar material out of bilges and double bottoms. If a fixed strainer becomes clogged with such materials, it is difficult to clear when there is any depth of water over it. e. Y-type strainers in steam piping are provided with a cleanout feature for cleaning the strainer basket. In some cases, this consists of a blowout valve arranged to discharge the bilge. In other cases, the strainer cap is used as a cleanout feature and must be removed in order to clean the basket. /. Observe the instructions regarding frequency of shifting baskets and the allowable pressure drop across fuel oil and lubrication-oil service system duplex strainer baskets. A gradual increase in pressure drop is normal and indicates that the strainer is effective. However, a decrease in differential pressure could mean that the basket has been damaged or leakage around the basket is occurring. ( 1) Each time the strainer is shifted and the basket cover is removed, the gasket should be examined carefully and replaced if it shows signs of unusual damage or wear, such as severe depressions on the surface, deep scratches, or cracks. If any doubt exists about the condition of the material, it should be replaced, using only approved gaskets as shown on the strainer drawings or the vessel allowance list. When replacing the strainer cover, insure that there is no dirt on the cover sealing surfaces. Insure that the gasket is properly located in its recess in the strainer body. Insure that the cover is properly seated in its recess and centered on the gasket and that the joint is bolted down evenly all around or properly secured by the cover clamp. (2) Vessel forces should fabricate and install a metal skirt for the basket cover. The skirt should be so arranged that any oil which might spray out, due to gasket failure or an improperly seated cover, will be deflected from the operator. The skirt should not interfere with proper cover joint makeup. AGO 5244A 331 ~~~~~~~~~''"1..>..__,__,._-'J,rnoooooorn !IIDDDDDD!Il rnoooooorn !IJDODDDD!Il moooooom moooooom IIIDDDODOill !IIDDODDDill 4 WAY PLUG COCK PLUG COCK IN POSITION FOR USE PLUG COCK THROUGH 180 DEGREES OF LEFT-HAND STRAINER BASKET FOR USE OF RIGHT-HAND STRAINER BASKET Figure 265. Duplex-type strainer. (3) After a clean strainer basket has been 311. Strainer Locations inserted in its compartment and the cover replaced, the compartment should be filled with oil so that it will a. Strainers are fitted in all piping lines to prevent passage of foreign matter which can be ready when shifting is required. This is accomplished by opening the vent valve on the cover and cracking obstruct pump valves or throttle valves. They also prevent damage to turbine blading, gearing, or other machinery or appliances to which the main switching valve so that oil the piping is connected. In certain cases, steam will enter and fill the compartment. turbines have a strainer incorporated in the Insure that the drain valve is shut. steam chest as part of the turbine design. In When all air has been vented, shut vent these cases, it is not necessary to provide an valve and return main switching valve to operating position. When shifting additional strainer in the piping for protecting the turbine. Strainers are installed so that the ( 4) baskets, the main switching valve should be moved very slowly so that pressure buildup is controlled. Any operation that results in hydraulic shock should be guarded against, as damage to the basket and in extreme cases to the cover joint could result. Use only bolting materials as shown on approved strainer drawings. Some duplex strainers have been designed to flow is into and through the perforated basket. In some places, such as the forced lubrication and fuel-oil lines, a duplex-type strainer is fitted to permit uninterrupted flow when closing off one strainer for cleaning. The valves or plug cocks should be marked to indicate the direction of flow and should be arranged so that both strainers cannot be closed off at the same time. use alloy steel bolting materials. If b. The installation of strainers in suction carbon-steel bolting materials are sub lines to the main-lubrication oil pumps and fuel stituted, the design safety factors are oil service pumps has been discontinued in new reduced considerably. construction. 332 AGO 5244A 312. Separator Maintenance Separators operate on the general principle of removing entrained liquids and solids from gases and vapors by using centrifugal force. Steam-system separators are fitted with vanes, guides, or baffles to impart a positive whirling motion to the gas or vapor. The resulting centrifugal force throws the contaminants, which are of greater density, against the separator walls, allowing the gas or vapor to continue unimpeded through the separator. The separated liquid collects in the separator pump from which it can be drained as necessary. Separators in .steam service are provided with trappeddrain connections to permit continuous drainage of condensate. Moisture separators in compressed-air service are arranged for manual draining by use of a needle valve. Because of . this, regular and periodic blowdown of the moisture separator is mandatory to maintain maximum efficiency and to prevent rusting of the separator. For maximum efficiency, separators should be installed in a straight length of pipe and at least 10 pipe diameters downstream of the nearest V~alve or fitting. 313. Filter Maintenance Filters are installed in fuel systems to remove solid contaminants and water from the fuel. Basically, the equipment is a two-state unit consisting of a coalescer (mixer) stage and a separator stage. Each stage is made up of replaceable elements, the number of which is determined by considerations such as the liquid processing capacity gallons per minute (gpm) of the element and its dirt-retaining capacity. Coalescer or mixer elements filter solids from the fuel and cause the small particles of undissolved water in the fuel to combine (coalesce) into larger drops of water. These will settle to the filter sump due to their weight. Separatar elements are provided to remove any remaining free water that has not combined. Water which has accumulated in the filter sump is removed through a drain line, either automatically or manually. The efficiency of the mixer and separator elements is basically dependent upon the condition of the fuel. Water in the fuel has less effect on shortening the life of the mixer elements than does solid contamination or dirt. Mixer elements can collect AGO 5244A only a limited amount of solids before they fail to filter the solids and fail to combine the water. Only be replacing these elements prior to this point can element failure and subsequent fuelsystem contamination be prevented. Note. Do not mix, within sets, coalescer or separator elements from different manufacturers, as they can have different pressure-drop characteristics. Coalescer element sets from manufacturer, however, can be used with separator element sets of another manufacturer. a. Transfer Filters. (1) Most JP-5 transfer filters are rated at 300 gpm but are flowed at 200 gpm to prolong their life. (2) A daily log of pressure drop and gallons pumped should be kept for each filter. As dirt accumulates in the coalescer elements, the pressure drop across the unit increases. By observing this pressure-drop buildup, the point at which element replacement is required can be anticipated and elements replaced before failure occurs first It should be noted that no increase in pressure drop is an indication that one or more coalescer elements are faulty. (3) When coalescer elements are changed, the separator elements will also be changed if any dirt is on the element. If separator elements are clean, they will be tested and only the defective elements replaced. Replacement elements will be tested before installation. ( 4) Vessels will deploy with a new set of filter elements in such :transfer filter and have 500 percent of installed elements aboard as spares. b. Service Filters: (1) The rate of flow through service filters for JP-5 and A vGas and the level of contamination of the fuel handled are extremely variable. Because of this, the pressure drop and total-gallons limits established for transfer filters cannot be utilized to indicate that element replaceme~t is necessary. It is recommended, therefore, that the elE! ments be replaced prior to deployment filter water sump contain solid or yearly. Elements should also be replaced when one of the following exists: (a) Analysis of fuel samples submitted to a labomtory indicates that more than 2.0 milligrams per liter of solids and/or water are passing through the filter. (b) The fuel samples taken during the monthly automatic water-drain and slug-control valve tests indicate that water is passing through the filter. (c) The daily samples taken from the particles. (d) The daily sample taken from the filter discharge section drain contains more than 4 ounces of water. Very small amounts of water can collect in this section from solution in the fuel and the cooling of the :fuel in service piping. (2) Both coalescer and separator elements should be replaced at the same time, unless one or the other is proved by test to be satisfactory. Replacement elements will be tested before installation. AGO 5244A CHAPTER 16 PAINTING, MARKING, AND INSIGNIA Section I. 314. General . Detailed requirements for the painting of U.S. Army floating equipment are outlined in Technical Bulletin TB 746-93-4. Colors and thicknesses have been extracted and included in this manual for convenience. Table XXVII is to be used as a guide and gives the square foot coverage and the thickness by millimeter obtained when using 1 gallon of paint by type and color. One brush stroke normally equals 1 millimeter. All surfaces must be thoroughly cleaned and dried prior to application of paint. Table XXVII. Painting Instructions Square foot coverage MilliType of paint (1 gallon of ameter paint) thickness Compound, canvas preservative _ 300____ 1 100____ Ena~el, black ---------------4 800____ Engine gray --------------1 Insignia blue _____________ 800____ 1 200____ Insignia red --------------4 Insignia white ____________ 300____ 2 400____ Yellow ------------------- 2 Light green _______________ 800____ 1 International orange _______ 400____ 2 400____ I>ark gray --------------- 2 350____ Light gray --------------- 4 Paint, antifouling _____________ 300____ 4 anticorrosive --------------4 300____ 350____ buff ---------------------- 3 Primer, zinc-chromate _________ 400____ 2 Paint remover ________________ 200____ 6 Varnish, asphalt_______________ 800____ 1 600____ clear --------------------- 1 315. Exterior Painting a. General. (1) Wood, canvas, and aluminum surfaces. Remove oil and grease from wood, canvas, and aluminum surfaces with an approved cleaner. Remove dirt and dust with fresh water and PAINTING detergent using brush or rag. Rinse with clean, fresh water. Dry thor oughly prior to sanding. (2) Steel surfaces. Remove rust, mill scale, and marine growth from steel surfaces by sandblasting or wire brushing. Remove oil and grease with solvent. Remove loose dirt and dust with a clean lint-free rag dampened with turpentine. b. Top Area. Paint the top areas of the vessel as follows: (1) Steel deck houses. Apply a light coat of pretreatment compound to steel deck houses, followed by two !-millimeter coats of primer. Paint the deck house with two coats of haze gray paint from the deck to a height of 9 inches. Use· two coats of white paint for the remaining height of the deck house. (2) Cabin trunks. Paint interior of cabin trunks white. Match color of adjacent exterior surfaces and apply two coats. (3) Bridge wings. Paint bridge wings white; apply two coats. ( 4) Mast, derrickse, flagstaffs, and ventilators. Paint mast, derricks, flagstaffs, and ventilators from the deck upward with two coats of buff enamel. (5) Ventilator interiors. Apply two coats of buff enamel to the interior of ventilators. c. Canvas. Treat awnings, windbreakers, flag bags, canvas covers on life boats, and searchlight covers with canvas preservative and paint to match surrounding area. AGO 5244A d. Frequently Handled Surfaces. Paint frames, hatches, and handrails the same color as adjacent areas. Paint fittings which constitute a trip hazard, such as bitts, cleats, anchors, and windlasses, with black enamel. e. Cockpit Decks, Coamings, and Cockpit Interiors. Paint cockpit decks and exterior sides with deck gray. Use haze gray on coamings. Paint cockpit interior decks with dark green deck paint, and interior bulkheads and overheads with pastel green, fire retarding paint. f. Hul~Topside to Boot Top. (1) Steel hulls from upper boot top area to bulkhead cap or first deck. Remove all old paint and foreign matter and apply one coat of pretreatment. Apply two coats of primer or red lead, 1 millimeter thick each, after pretreatment is dry. Then apply two coats of black or haze gray hull paint, each 1 millimeter thick. (2) Wood hull from upper boot top to bulkhead cap or first deck. Paint hull with two light coats of aluminum paint, each 0.5 millimeter thick, after hull has been cleaned and sanded. Apply two coats of haze gray paint, each 1 millimeter thick, after aluminum paint drys. g. Bottom. (1) Steel bottom including appendages, strainers, and sea chest. Apply one light coat of pretreatment, 0.5 milimeter thick, to clean, bare metal. After drying, apply four coats of anticorrosive primer, total thickness of 4.5 millimeters. After drying, apply three coats of antifouling, red, cold plastic with a total minimum dry film thickness of 10 millimeters. (2) Wood bottom including appendages cmd strainers. Apply three coats of antifouling, red, cold pla.Stic with a total thickness of 10 millimeters to clean, dry surface. 316. Interior Painting a. Hull and Cabin Interior. (1) Steel surfaces. The hull and cabin interior includes all steel decks and bulkheads. After the old paint has been removed and the surfaces cleaned, apply one coat of zinc-chromate primer, 1 millimeter thick, to all surfaces. Paint decks of wardrooms, staterooms, pilot house, messrooms, and washrooms dark green, two coats, 1 millimeter thick each. Paint the bulkheads and overheads fire retarding white, two coats, 1 millimeter thick each. (2) Wooden surfaces. Paint clean, sanded, wooden hull and cabin interior with two coats of fire retarding semigloss white, two coats, 1 millimeter thick each, 6 inches above the deck upward. Paint woden decks and walking flats up to a point 6 inches above the deck with two coats of dark green paint, 1 millimeter thick each. b. Engine Rooms, Engine Compartments, and Engine Boxes. After removal of old paint and thorough cleaning, paint all metal surfaces with one coat of zinc-chromate primer, 1 millimeter thick. After drying, apply two coats of fire retarding white paint, 1 millimeter thick each, from a point 12 inches above the deck. c. Engine Room Decks and Walking Flats. (1) Steel surfaces. After removal of old paint and thorough cleaning, apply one coat of zinc-chromate primer, 1 millimeter thick, down from a point 12 inches above the deck. Allow to dry, then apply two coats of black deck paint, 1 millimeter thick each. Gratings and floor plates or deck plates in the engine room will be left unpainted on vessels in active status. Vessels destined for storage or those in storage will be protected as prescribed in Technical Bulletin TB 746-93-4. (2) Wooden surfaces. Paint wooden hull engine rooms with two coats of deck gray, 1 millimeter thick each. d. Decks and Steel Washbands. (1) Steel surfaces. Apply one coat of zincchromate primer, one millimeter thick, downward from a point 9 inches above deck. Allow to dry, and then apply two coats of green deck paint, one millimeter thick each. AGO 5244A (2) Wooden surfaces. Apply two coats of painted will be thoroughly cleaned. All rust, oil, grease, loose and blistered paint, ·deteriorated gray deck paint, 1 millimeter thick areas of old paint, and other surface contamina each, to wooden decks. tors will be removed prior to painting. After e. Bilge Area and Floor Plates. Painting of cleaning, apply two coats of red lead primer, the bilge area includes bilge wells and sumps. 1-millimeter thickness for each coat. After the Floor plate painting is restricted to the bottom primer has dried, apply two coats of red deck and sides as the tops are left bare. When major paint, 1-millimeter thickness for each coat. painting is to be performed, all surfaces to be Allow adequate drying between coats. Section II. MARKING AND INSIGNIA LOCATION LAYOUT PREFERRED DESIGNATION ARRANGEMENT !STARBOARD SIDE SHOWN} ALTERNATE DESIGNATION ARRANGEMENT !STARBOARD SIDE SHOWN} NOTE: INSIGNIA WILL BE PLACED FORWARD OF DESTINATION ON PORT AND STARBOARD SIDES. SIZE OF VESSEL DIMENSIONS IN INCHES (LOAD WATER LINE LENGTH IN FEET) A B c LESS THAN 20 3 4 2 20 TO LESS THAN 40 4 112 6 3 40 TO LESS THAN 70 6 8 4 70 TO LESS THAN 125 7 112 10 5 125 AND OVER 9 12 6 DIMENSIONS FOR DESIGNATIONS Figure 266. Designation a1·rangements. AGO 5244A 337 G\3;~~ (C [OJ OY~[02S 0.83 I-_jf I-0.75 ~(TYPICAL LETTER WIDTH, UNLESS OTHERWISE INDICATED} TII[JJ. !OJ 0.37 _L~~£F~"rlru ~~'"1 GJJ 0.10 l-045 ~ ---J r0.08 f-~0.63~. 0 37 I oi 17 -~ t ~0.67 I OY-c~ (Q) 0.25 NOTE: 1. ALL DIMENSIONS ARE DECIMAL FRACTIONS OF THE HEIGHT (H). SEE FIG. 266. 2. WIDTH OF BARS USED FOR LETTERS AND NUMERALS IS 0.17 (1/6) OF THE HEIGHT (H). 3. EXCEPT WHERLC OTHERWISE SHOWN, ALL OUTSIDE CORNER BEVELS SHALL BE AS SHOWN. SEE NOTE 3 Figure 267. Block letters and numerals. AGO 5244A 317. General . Block lettering and numerals are used on exteriors of all watercraft. All lettering is to be in Gothic style and numerals will be Arabic. Colors are black on white background or white on black background. Figures 266, 267, and 268 illustrate the correct size of marking by the type of the vessel. 318. Type of Vessel Wooden hulls will have the draft and load marking cut 1!s inch wide and 1!s inch deep and will be painted using the same style as the lettering. Steel hulls will have the draft and load lines marked with a fine weld bead outline and painted the same as the lettering. 319. Bow and Transom Designation a. Bow designation will be located at the hull or bulwark on port and starboard sides, and centered three-fourths of the height from the design load waterline and arranged in two lines. On tugs, the bow designation will be located clear of the installed fender guard and bumpers. b. Stern designation will be the same as the bow on the hull or bulwark. On vessels having transom or elliptical sterns, the designation will be centered horizontally on the vertical centerline through the hull. Vessels with cruiser sterns will have the designation located near the stern on both port and starboard sides. On transom and cruiser sterns, designation will be cen- H 2/3 NOTE: DIMENSIONS ARE FRACTIONAL PART OF STACK HEIGHT (H). Figure 268. Painting of stack for peacetime. AGO 5244A tered at approximately three-fourths of the height of the designed load waterline to the upper edge of the deck or bulwark. On elliptical sterns, designation will be centered midway between the fantail knuckle and the upper edge of the deck or bulwark. c. Name boards will be painted black with gold colored letters. d. Shipformed hulls, nonpropelled, will be marked the same as propelled vessels. e. Barges with deck houses will have the designation marking centered on the deck house, both port and starboard, and the same designation centered at the fore and aft ends. /. On barges without deck houses, the designation will be centered 12 inches longitudinally amidships, both port and starboard. The same designation will be centered on the bow and stern below the deck edge. g. Floating crane hulls will be marked with designations the same as barges without deck houses. In addition, the cab of the crane will have the designation centered on each side of the cab. 320. Boat Designator and Serial Number Location These will be carried on the forward cabin or forward deck of the watercraft. Size of the lettering will be determined by the size of the vessel. 321. Service Designation and Boat Designator for Ring Buoys and Noninflatable Rafts Service designation and boat designator will be marked on the face of ring buoys and noninflatable life rafts. These mar]fings will be on a line around the circumferenc~, centered on the face width. The service de~ignation will be placed at the top and the boat designator at the bottom of ring buoys. Service Besignation and boat designator will be placed at opposite ends of life rafts Both parts of designation will read from left to right. Letters and numbers will be 2lj2 inches high on ring buoys and 31/2 inches high on life rafts. All characters will be in black deck enamel. CHAPTER 17 REPAIR SPECIFICATIONS 322. General Accurate logs, reports, and records are of prime importance in maintaining the vessel in good operating condition. These logs, reports, and records provide a means of determining the condition of the vessel in general, condition of the equipment, and necessary repairs. Inspectors use the logs, reports, and records to deter-mine the repair necessary and to initiate a request for maintenance. 323. Typical Repair Specifications Typical procedures and the necessary logs, reports, and records for vessel or equipment repair beyond the capabilities of the vessel crew are as follows: a. Vessel Deck Log. The vessel deck log, DA Form 55-40, lists data pertaining to the condition of the entire vessel and equipment, except engine and machinery equipment. This log is used in the preparation of a request for maintenance. b. Engine Department Log. The engine department log, DA Form 55-44, lists data pertaining to the condition of the engine and machinery equipment. This log is used in the preparation of a request for maintenance. c. Maintenance Request. The maintenance request, DA Form 2407, is prepared and submitted to the supporting maintenance and repair shop when necessary repairs are beyond the maintenance capability of the using unit. Maintenance shop personnel screen each request. All repairs beyond the mission capability of the maintenance shop become the responsibility of the supporting depot. The maintenance request form is then forwarded to the Marine Inspection Section for processing. An example of a prepared DA Form 2407 is shown in figure 269. d. Inspection. Upon receipt of DA Form 2407, the Marine Inspection Section will inspect the vessel or major component, as listed on the repair request and validate the requirement. A formal letter is prepared by the Marine Inspection Section and forwarded through command channels to the supporting depot repair agency. Formal letter requests are prepared and forwarded to the depot repair agency covering one of three different support actions. Types of letters are as follows: (1) Scheduled annual repair requests (every 18 rrionths for propelled and 24 months for nonpropelled vessels). Example: (localletterhead) Subject: Emergency Request, U.SST 2122 Depot . Army Vessel Repair To: (supporting agency) depot repair 1. Enclosed herewith for your information and necessary action are two copies of subject request as compiled by operating personnel. 2. Vessel is available for your survey and located at the 3rd Port Area, Fort Eustis, Virginia. (Signed in accordance with local procedure.) (2) Emergency requests (immediate action, based on operational justification). Example: (localletterhead) Subject: Emergency Depot Repair Request, U.S. Army Vessel ST 2122 To: (supporting depot repair agency) 1. Request that immediate action be taken to accomplish necessary repairs on subject vessel. AGO 5244A •See .eveue of file PAGE NO. I INO. OF ;_AGES I REPORTS CONTROL SYMBOL MAINTENANCE REQUEST copy for codes and · 1 CSGLD-1047 (RI)(TM 38-750) additional data. 00 WORK REQUEST 0 IIWO 0 EIR c:::J ~~~~H~~~OT~~THY SECTION I DESIGNATOR CODE CONTROL HUMBER lo. ORGANIZATION b. LOCATION '· ORG IDE NT CODE 26.3754 330TH HVY BOAT CO. FT EUSTIS, VA WWDED 2. SERIAL HUMBER 3. NOUN HOMEHCLATUR E "· LINE NUMBER S. MODEL 6. FE-DERAL STOCK HUMBER LCU 1663 Landing. Craft 750030 1466 1905-217-2293 B. UTILIZA~CODE' 9.~ECTED !TEll 10. HOURS 111. IIILES 12. ROUNOSr. STARTS ON YES Ol]HO 7. STRAC CIIl YES ~NO U. FAILURE DETECTED DURING (Select one-use\,/ or X) lS.~IHDICATIOH OF TROUBLE (Select one-use'!;' or X) CI!J SCHEDULED ~TEST []])STORAGE CikiFLIGHl INOPERATIVE C!lmOVERHEATIHG cr:niDOUT OF ADJUSTMENT MAINTENANCE NORMAL CIEI]HOISY o:n!)LOW PERFORMANCE o::::JOTHER DIJ HANDLING OPERATION Dl]IHSPECTIOH CI!!J OTHER 16. DESCRIBE DEFICIENCIES OR SYMPTOMS ON THE BASIS OF COMPLETE CHECKOUT AND DIAGNOSTIC PROCEDURE IN EQUIPMENT TM (Do not prescribe repairs) Motor Generator Set,./"\.(Aboard Vessel), Allis-Chalmers Mfg Co. Ser No 2N-466-45 INPUT; 115 VoltsflC,<") 14 AMP, 60 Cycle, 3600 RPM. OUTPUT: 1KW. CONDITION: Slip\.r~excessively worn, bearings defective, brushes worn, commutator worn, 1 windings and rotor dMy. /) 1~ "\-- ~IONII -WORK ACCOMPLISHED 17a. REPAIR ORGANIZATION/ACTIVITY c. ORG/ACT IDEHT CODE 18. TYPE ORGAHIZATIOHIACTIVITY ACCOM.-19. AMS ACT. CODE PLISHIHG WORK (Select one-u.se \ or X) II b. LOCATION v CTIJTOE CIIJTD ~ CI!J CONTRACTOR FAILURE '· COIIPOHEHT/PART NOUN, SERVICE, O~WO HO-d_ / g.MAH HOURS• h. FEDERAL STOCK HUMBER j. k. PARTS cooe• (Hnurs & VART' QUANTITY COST A~~ b. d. CB CODE I·· REFERENCE DESIGHAT!!l'll"\. Ml'R. ~DE tenths) s~~~~E I I II I I v / ") I I <./. /.-". I I ....., -/ I ' I I -// I v /_'\. I I I / ()) I v '-"' I I /) I // m. TOTAL PARTS 1. TOTAL MAHHOURS n, ~'HHOURS '0 COST 21. DELAY (Select one DATA TRANSCRIBED TO LOG BOOK [Ij]PARTS "C:rn',.!~POWER c::Il] FACILITIES CJil FUNDS V'"~s 22. 23. SUBMITTED BY 24. RECEIVED BY 2S. WORK STARTED BY 26. INSPECTED BY 27. ACC(_N' J6· DISPOSITION (Select one - I. M. WRITE usf' \ or X) a:tlsALVAGED JULIAN DATE JULIAN DATE JULIAN DATE JULIAN DATE JULIAHDAV 0AJTO USER ernEVACUATED DIJCAHHIBALIZA· 2045 CIID TO STOCK TION SECTION Ill-EQUIPMENT IMPROVEMENT RECOMMENDATION 31. RI!COMMI!MDATIOM (Select o.e ... 'V 32•. ORGANIZA TIOH/ACTIVITY c. ORG/ACT IDE NT CODE ·•· ~m~t:r lO.EIR f~~':~/ ::x) or XJ(Select Cl Table XXVIII. Typical Types of Nails "" "'... ... > Nomenclature Roofing nails Roofing nails (Neoprene washer attached; with or without spiral shank; designed primarily for application of aluminum roofing) Spiral shank aluminum siding nails Spiral shank asbestos s.iding nails (special needle point) Insulated siding nails Length (inches) 7/8 1 1-1/4 1-1/2 1-3/4 2 2-1/2 1-3/4 1-3/4 2 2-1/2 2-1/2 1-1/2 1-1/8 1-7/16 1-3/4 2 2-1/2 Gage 10 10 10 10 10 10 10 10 Spiral 10 10 Spiral Spiral Spiral Spiral Spiral 11-1/2 10 Decimal equivalent (inches) 0.135 0.135 0.135 0.135 0.135 0.135 0.135 0.135 0.145· 0.135 0.135 0.150 0.120 0.102 0.104 0.105 0.113 0.135 Head diameter (inches) 7/16 7/16 7/16 7/16 7/16 7/16 7/16 7/16 7/16 7/16 7/16 7/16 5/16 3/16 3/16 3/16 7/32 7/32 Approximate pieces (per pound) 663 605 491 417 368 336 274 318 288 285 243 215 550 1150 900 720 495 295 w ~ w '!:abl~ XXYIII. TYQi9JI,l_Types of.Nails.JCon_!} o- Oil Nomenclature Length Gage Decimal Head Approximate equivalent diameter pieces (inches) (inches) (inches) (per pound) Wood siding nails, 1-7/8 11•3/4 0.109 17/64 566 sinker head 2-1/8 11-1/2 0.113 17/64 468 2-3/8 10-1/2 0.128 19/64 319 2-7/8 9-1/2 0.142 5/16 215 Wood siding nails, case 1-7/8 11-3/4 0.109 9/64 566 head 2-1/8 11-1/2 0.113 9/64 468 2-3/8 10-1/2 0.128 5/32 319 2-7/8 9-1/2 0.142 3/16 215 Cedar shake nails 1-3/4 12-1/2 0.099 5/32 724 Gypswn lath nails 1-1/8 12-1/2 0.099 5/16 988 1-1/4 12-1/2 0.099 5/16 939 1-1/2 12 0.105 5/16 725 Common nails 1-1/2 12-1/4 0.102 1/4 800 2 11 0.120 17/64 425 2-1/2 9 0.148 9/32 230 Asbestos roof shingle 1-1/4 11-1/2 0.113 5/16 785 nails 1-1/2 11-1/2 0.113 5/16 659 1-3/4 11-1/2 0.113 5/16 544 > Cl "' ..."" ... > > Table XXIX. Threads, Tap Drills, and Gages Cl .., "' ... ... > Decimal equivalent Nominal OUtside Pitch Root of size diameter diameter diameter Tap drill tap drill (inches) (inches) (inches) * 0-80 0.0600 0.0519 0.0438 3/64 0.0469 * 1-64 0.0730 0.0629 0.0527 53 0.0595 72 0.0730 0.0640 0.0550 53 0.0595 * 2-56 0.0860 0.0744 0.0628 50 0.0700 64 0.0860 0.0759 0.0657 50 0;0700 * 3-48 0.0990 0.0855 0. 0719 47 0.0785 56 0.0990 0.0874 0.0758 45 0.0820 * 4-40 0.1120 0.0958 0.0795 43 0.0890 48 0.1120 0.0985 0.0849 42 0.0935 * 5-40 0.1250 0.1088 0.0925 38 0.1015 44 0.1250 0.1102 0.0955 37 0.1040 * 6-32 0.1380 0.1177 0.0974 36 0.1065 40 0.1380 0.1218 0.1055 33 0.1130 * 8-32 0.1640 0.1437 0.1234 29 0.1360 36 0.1640 0.1460 0.1279 29 0.1360 *10-24 0.1900 0.1629 0.1359 25 0.1495 32 0.1900 0.1697 0.1494 21 0.1590 *12-24 0.2160 0.1889 0.1619 16 0.1770 28 0.2160 0.1928 0.1696 14 0.1820 1/4 -20 0.2500 0.2175 0.1850 7 0.2010 28 0.2500 0.2268 0.2036 3 0.2130 5/16-18 0.3125 0.2764 0.2403 F 0.2570 24 0.3125 0.2854 o. 2584 I 0.2720 3/8 -16 0.3750 0.3344 0.2938 5/16 0.3125 24 0.3750 0.3479 0.3209 Q 0.3320 w ~ w Table XXIX. Threads, TaQ Drills, _ar1<1 Gages (Co_!lt) ~ Decimal equivalent Nominal Outside Pitch Root of size diameter diameter diameter Tap drill tap drill (inches) (inches) (inches) 7/16 -14 0.4375 0.3911 0.3447 u 0.3680 20 0.4375 0.4050 0.3726 25/64 0.3906 1/2 -13 0.5000 0.4501 0.4001 27/64 0.4219 20 0.5000 0.4675 0.4351 29/64 0.4531 9/16 -12 0.5625 0.5084 0.4542 31/64 0.4844 18 0.5625 0.5264 0.4903 33/64 0.5156 5/8 -11 0.6250 0.5660 0.5069 17/32 0.5312 18 0.6250 0.5889 0.5528 37/64 0.5781 3/4 -10 0.7500 0.6850 0.6201 21/32 0.6562 16 0.7500 0.7094 0.6688 11/16 0.6875 7/8 -9 0.8750 0.8029 0.7307 49/64 0.7656 14 0.8750 0.8286 0.7822 13/16 0.8125 1 -8 1.0000 0.9188 0.8376 7/8 0.8750 14 1.0000 0.9536 0.9072 15/16 0.9375 1-1/8 -7 1.1250 1.0322 0.9394 63/64 0.9844 12 1.1250 1.0709 1.0168 1-3/64 1.0469 1-1/4 -7 1. 2500 1.1572 1.0644 1-7/64 1.1094 12 1.2500 1.1959 1.1418 1-11/64 1.1719 1-3/8 -6 1.3750 1. 2667 1.1585 1-7/32 1. 2187 12 1.3750 1.3209 1.2668 1-19/64 1.2969 1-1/2 -6 1.5000 1. 3919 1.2835 1-11/32 1.3437 12 1. 5000 1.4459 1. 3918 1-27/64 1.4219 1-3/4 -5 1.7500 1.6201 1.4902 1-9/16 1.5625 2 -·4-1/2 2.0000 1.8557 1. 7113 1-25/32 1. 7812 > C'l 0 "' ~ ~ "' > >0 Table XXIX. Threads, Tap Drills, and Gages (Cont) 0 "' "'... ... > Decimal equivalent of Nominal Outside Pitch Root size diameter diameter diameter Tap drill tap drill (inches) (inches) (inches) 2-1/4 -4-1/2 2.2500 2.1057 1.9613 2-1/32 2. 0312 2-1/2 -4 2.5000 2.3376 2.1752 2-1/4 2.2500 2-3/4 -4 2.7500 2.5876 2.4252 2-1/2 2.5000 3 -4 3.0000 2.8376 2.6752 2-3/4 2.7500 3-1/4 -4 3.2500 3.0876 2.9252 3 3.0000 3-1/2 -4 3.5000 3.3376 3.1752 3-1/4 3.2500 3-3/4 -4 3.7500 3.5876 3.4252 3-1/2 3.5000 4 -4 4.0000 3.8376 3.6752 3-3/4 3.7500 *Machine screw-sizes w ...... - w ~ Table XXX. Areas and Circumferences of Circles from 1/32 to 10 Inches in Diameter Dia 1/32 3/64 1/16 3/32 1/8 5/32 3/16 7/32 1/4 9/32 5/16 11/32 3/8 13/32 7/16 15/32 Area 0.00077 0.00173 0.00307 0.00690 0.01227 0.01917 0.02761 0.03758 0.04909 0.06213 0.07670 0.09281 0. 11045 0.12962 0.15033 0.17257 Circ Dia Area Circ Dia Area Circ 0.098175 2 3.1416 6.. 28319 5 19.635 15.7080 0.147262 1/16 3.3410 6.47953 1/16 20.129 15.9043 0.196350 1/8 3.5466 6.67588 1/8 20.629 16.1007 0.294524 3/16 3.7583 6.87223 3/16 21. 135 16.2970 0. 392699 1/4 3.9761 7.06858 1/4 21.648 16.4934 0.490874 5/16 4.2000 7.26493 5/16 22.166 16.6897 0.589049 3/8 4.4301 7. 46128 3/8 22.691 16.8861 0.687223 7/16 4.6664 7.65763 7/16 23.221 17.0824 0. 785398 1/2 4.9087 7.85398 1/2 23.785 17.2788 0. 883573 9/16 5.1572 8.05033 9/16 24.301 17.4751 0.981748 5/8 5. 4119 8.24668 5/8 24.850 17.6715 1. 07992 11/16 5.6727 8.44303 11/16 25.406 17.8678 1. 17810 3/4 5.9396 8. 63938 3/4 25.967 18.0642 1. 27627 13/16 6.2126 8. 83573 13/16 26.535 18.2605 1. 37445 7/8 6.4918 9.03208 7/8 27.109 18.4569 1. 47262 15/16 6. 7771 9.22843 15/16 27.688 18.6532 > G"l "' .. "" ... > > C'l 0 "' ... "' ... Table XXX. Areas and Circumferences of Circles > from 1/32 to 10 Inches in Diameter (Cont) Dia Area Circ Dia Area Circ Dia Area Circ 1/2 0.19635 1. 57080 3 7.0686 9.42478 6 28.274 18.8496 17/32 0.22166 1. 66897 1/16 7.3662 9. 62113 1/8 29.465 19.2423 9/16 0.24850 1. 67615 1/8 7.6699 9.81748 1/4 30.680 19.6350 19/32 0.27688 1. 86532 3/16 7.9798 10.0138 3/8 31.919 20.0277 5/8 0.30680 1. 96350 1/4 8.2958 10.2102 1/2 33.183 20.4204 21/32 0.33824 2.06167 5/16 8.6179 10.4065 5/8 34.472 20.8131 11/16 o. 37122 2. 15984 3/8 8.9462 10.6029 3/4 35.785 21. 2058 23/32 0.40574 2.25802 7/16 9.2806 10.7992 7/8 37.122 21.5984 3/4 0.44179 2.35619 1/2 9.6211 10.9956 7 38.485 21.9911 25/32 o. 47937 2.45437 9/16 9.9678 11. 1919 1/8 39.871 22.3838 13/16 0.51849 2.55254 5/8 10.321 11.3883 1/4 41.282 22.7765 27/32 0.55914 2.65072 11/16 10.680 11.5846 3/8 42.718 23.1692 7/8 0.60132 2.74889 3/4 11.045 11.7810 1/2 44.179 23.5619 29/32 0.64504 2.84707 13/16 11.416 11.9773 5/8 45.664 23.9546 15/16 0.69029 2.94524 7/8 11.793 12. 1737 3/4 47.173 24.3473 31/32 o. 73708 3.04342 15/16 12.177 12.3700 7/8 48.707 24.7400 w ~ w ~ Table XXX. Areas and Circumferences of Circles from 1/32 to 10 Inches in Diameter pont) Dia 1 1/16 1/8 3/16 1/4 5/16 3/8 7/16 1/2 9/16 5/8 11/16 3/4 13/16 7/8 15/16 > p "' .... "" ... > Area 0.78540 0.88664 0.99402 1. 1075 1. 2272 1. 3530 1. 4849 1. 6230 1. 7671 1. 9175 2.0739 2.2365 2.4053 2.5802 2.7612 2. 9483 Circ Dia Area Circ Dia Area Circ 3.14159 4 12.566 12.5664 8 50.265 25.1327 3.33794 3.53429 1/16 1/8 12.962 13.364 12.7627 12.9591 1/8 1/4 51.849 53.456 25.5224 25.9181 3.73064 3.92699 3/lfi 1/4 13.772 14.186 13.1554 13.3518 3/8 1/2 55.088 56.745 26.3108 26.7035 4.12334 4.31969 4.51604 5/16 3/8 7/16 14.607 15.033 15.466 13.5481 13.7445 13. 9408 5/8 3/4 7/8 58.426 60.132 61.862 27,0962 27.4889 27.8816 4. 71239 1/2 15.904 14.1372 9 63.617 28.2743 4.90874 5.10509 5.30144 5.49779 5.69414 5.89049 6.08684 9/16 5/8 11/16 3/4 13/16 7/8 15/16 16.349 16.800 17.257 17.721 18.190 18.665 19.147 14.3335 14.5299 14.7262 14.9226 1.5. 1189 15.3153 15.5116 1/8 1/4 3/8 1/2 5/8 3/4 7/8 65.397 67.201 69.029 70.882 72.760 74.662 76.589 28.6670 29.0597 29.4524 29.8451 30.2378 30.6305 31. 0232 P> Table XXXI. Cl U.S. Standard Gage for Sheet and Plate Iron and Steel ~ ... ... > No. of gage 0000000 000000 00000 0000 000 00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Approximate thickness (fractions of an inch) 1/2 15/32 7/16 13/32 3/8 11/32 5/16 9/32 17/64 1/4 15/64 7/32 13/64 3/16 11/64 5/32 9/64 1/8 7/64 3/32 5/64 9/128 1/16 9/160 Approximate thickness (decimal parts of an inch) 0.5 0.46875 0. 4375. 0.40625 o. 375 0.34375 0.3125 0.28125 0.265625 0.25 0.234375 0.21875 0.203125 0.1875 0. 171875 0•. 15625 0.140625 0.125 o. 109375 o. 09375 0.078125 0.0703125 0.0625 0.05625 Approximate weight (pounds per square foot) 20. 18.75 17.5 16.25 15. 13.75 12.5 11.25 10.625 10. 9. 375 8. 75 8.125 7.5 6.875 6.25 5.625 5. 4. 375 3.75 3.125 2.8125 2.5 2. 25 w ~ w ~ Table XXXI. U.S. Standard Gage for Sheet and Plate Iron and Steel (Cont) No. of gage 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 > Cl 0 01 .... "' .... > Approximate thickness (fractions of an inch) 1/20 7/160 3/80 11/320 1/32 9/320 1/40 7/320 3/160 11/640 1/64 9/640 1/80 7/640 13/1280 3/320 Approximate thickness (decimal parts of an incll) 0.05 0.04375 0.0375 0.034375 0.03125 0.028125 0.025 0.021875 0.01875 0.0171875 0.15625 0.0140625 0.0125 o. 0109375 0.01015625 0.009375 Approximate weight (pounds per square foot) 2. 1. 75 1.5 1. 375 . 1. 25 1.125 1. o. 875 0.75 0.6875 0.625 0.5625 0.5 0.4375 0.40625 0.375 > Cl ___]'~_ble XXXII. Weights of Sheets and Plates__9f Steel, Copper, and Brass "' ..."" ... > Weight (pounds per square foot) No. of Thickness Gage (inches) Steel Copper Brass 0000 0.460000 18.7680 20.8380 19.6880 000 0.409642 16. 7134 18.5568 17.5327 00 0.364796 14. 8837 16.5254 15.6133 0 0.324861 13.2543 14. 7162 13. 9041 1 0.289297 11. 8033 13.1052 12.3819 2 0.257627 10. 5112 11.6705 11.0264 3 o. 229423 9.3605 10.3929 9.8193 4 0.204307 8.3357 9.2551 8.7443 5 0.181940 7.4232 8.2419 7.7870 6 0.162023 6.6105 7. 3396 6.9346 7 0.144285 5.8868 6.5361 6.1754 8 0.128490 5.2424 5.8206 5.4994 9 0.114423 4.6685 5.1834 4.8973 10 0.101897 4. 1574 4.6159 4.3612 11 0.090742 3.7023 4. 1106 3. 8838 12 0.080808 3.2970 3.6606 3.4586 13. 0. 071962 2. 9360 3.2599 3.0800 14 0.064084 2.6146 2.9030 2. 7428 15 0.057068 2.3284 2.5852 2.4425 16 0.050821 2.0735 2.3022 2.1751 17 0.045257 1. 8465 2.0501 1. 9370 18 0.040303 1. 6444 1. 8257 1. 7250 Table XXXII. Weights of Sheets and Plates of Steel, Copper, and Brass (Cont) Weight (pounds per square foot) No. of Thickness Gage (inches) Steel Copper Brass 19 0.035890 1. 4643 1. 6258 1. 5361 20 0.031961 1. 3040 1. 4478 1. 3679 21 0.028462 1. 1612 1. 2893 1. 2182 22 0.025346 1. 0341 1. 1482 1. 0848 23 0.022572 0.92094 1. 0225 0.99608 24 0.020101 0.82012 0.91058 0.86032 25 0.017900 0.73032 0.81087 0.76612 26 0.015941 0.65039 0.72213 0.68227 27 0.014195 0.57916 0.64303 0.60755 28 0.12641 0.51575 0.57264 0.54103 29 o. 011257 0.45929 0.50994 0.48180 30 0.010025 0.40902 0.45413 0.42907 31 0.008928 0.36426 0.40444 0.38212 32 0.007950 0.32436 0.36014 0.34026 33 0.007080 0.28886 0.32072 0.30302 34 0.006305 0.25724 0.28562 0.26985 35 0.005615 0.22909 0.25436 0.24032 36 0.005000 0.20400 0.22650 0.21400 37 0.004453 0.18168 0.20172 0.19059 38 0.003965 0.16177 0.17961 0.16970 39 0.003531 0.14406 0.15995 0. 15113 40 0.003144 0.12828 0.14242 0.13456 ;l> C) 0 "' ... "" ... > Table XXXIIT. Solid Aluminum Antimony Bismuth Brass Bronze Cadmium Chromium Cobalt Copper Gold Iridium Iron-cast, gray Iron -cast, white Iron -wrought Lead Magnesium Manganese Mercury Nickel Palladium Platinum Potassium Rhodium Silver Sodium Steel -mild Steel -hard Tin Vanadium .·Zinc Melting Points or Temperatures of Fusion Degrees Centigrade 656 630 268 1030 920 320 1487 1463 1084 1064 2500 1220 to 1530 1050 to 1135 1500 to 1600 327 750 1207 -39.7 1435 1546 1753 62 2000 953 95 1475 1420 232 1775 419 Degrees Fahrenheit 1214 1166 514 1886 1688 608 2709 2665 1983 1947 4532 2228 to 2786 1922 to 2075 2732 to 2912 620 1382. 2205 -39.5 2615 2815 3187 144 3632 1747 203 2687 2588 449 3227 786 AGO 5244A 379 w CD Table XXXIV. Tyeical Tensile and Bearing Properties of Aluminum Alloy Plates and Shapes Bearing properties Tensile properties Edge distance =1. 5 Edge distance = 2. 0 X rivet diameter X rivet diameter Alloy Yield Ultimate Yield Ultimate Yield Ultimate strength strength strength strength strength strength (psi) (psi) (psi) (psi) (psi) (psi) 1100-0 5,000 13,000 10, 000 21,000 12,000 27, 000 1100-H12 15,000 16,000 18,000 23,000 21,000 29,000 1100-H14 17,000 18,000 20,000 25,000 23,000 31, 000 1100-H16 20,000 21,000 23,000 28,000 26,000 34,000 1100-H18 22,000 24,000 27,000 31,000 32,000 38, 000 2014-T4 42,000 62,000 56,000 93,000 64,000 118, 000 2014-T6 60,000 70,000 84,000 105,000 96,000 133,000 Alclad 2014-0 10, 000 25,000 .. . . . . . . . . . . . . .. . ..... Alclad 2014-T3 40, 000 63,000 55,000 90, 000 62, 000 114, 000 Alclad 2014-T6 60,000 68,000 83,000 100, 000 94, 000 127,000 2017-T4 40,000 62,000 56,000 93,000 64,000 118, 000 2024-T3 50,000 70,000 64,000 102,000 74, 000 129, 000 Alclad 2024-T3 45,000 65,000 60,000 96,000 69,000 122, 000 2024-T36 57, 000 72,000 80,000 110, 000 91,000 139, 000 Alclad 2024-T36 53,000 67,000 74,000 100,000 85,000 127, 000 > ~ "" ..."" ... > ;I> Cl Table XXXIV. Typical Tensile and Bearing Properties of Aluminum Alloy ... "' "' ... > Plates and Shapes (Cont) Bearing properties Tensile properties . Edge distance =1. 5 Edge distance = 2. 0 X rivet diameter X rivet diameter Alloy Yield Ultimate Yield Ultimate Yield Ultimate strength strength strength strength strength strength (psi) (psi) (psi) (psi) (psi) (psi) 3003-0 6, 000 16,000 12,000 25,000 15,000 34,000 3003-H12 18, '000 19,000 21,000 27,000 24,000 36,000 3003-H14 21,000 22,000 24,000 30,000 29, 000 38,000 3003-H16 25, 000 26,000 28,000 34,000 33,000 42,000 3003-H18 27, 000 29,000 32,000 38,000 38,000 46,000 5052-0 13, 000 28,000 25,000 46,000 30,000 61,000 5052-H32 28, 000 33,000 37,000 54,000 42,000 71, 000 5052-H34 31,000 38,000 41,000 59, 000 47,000 78;000 5052-H36 35, 000 40,000 47,000 62,000 54,000 82;000 5052'-H38 37,000 42,000 50,000 66,000 58,000 86,000 6061-T4 21, 000 35,-000 29,000 56,000 34,000 73,000 6061-T6 40,000 45,000 56,000 72,000 64,000 94,000 7075-T6 73,000 83,000 101,000 123,000 115, 000 156,000 Alclad 7075-T6 67,000 76,000 94,000 114,000 107, 000 144,000 w CD - Table XXXV. Recommended Hole Sizes for Hot-driven Aluminum Alloy Rivets with Corresponding Shear and Bearing Areas Nominal rivet diameter (inches) 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 Recommended hole diameter (inches) 0.397 0.469 0.531 0.594 0.656 0.781 0.922 1.063 Corresponding drill size X 15/32 17/32 19/32 21/32 25/32 59/64 1-1/16 Corresponding single shear area (square inches) 0. 1238 0.1728 0.2215 0. 2771 0. 3380 0.4791 0.6677 0.8875 Bearing area for various sheet and plate thickness (square inches) 0.032 0.040 0.051 0.064 0.081 0.102 1/8 5/32 3/16 7/32 1/4 5/16 3/8 7/16 1/2 9/16 5/8 11/16 3/4 13/16 7/8 1 ..... ..... 0 0 ••• .... . . 0.0322 0.0405 0.0496 0.0620 0.0744 0.0868 0.0993 0.1241 0. 1489 •• 0 •• ..... ..... . . . . . • • • 0 • ..... .... . . . . . . • 0 ••• .... . ... .. • •• 0 • . .... ..... 0.0478 0.0586 0.0733 0. 0879 0.1026 0. 1173 0.1466 0.1759 0.2052 . .... . .... ... . . ••• 0 • • •• 0 • . . .... 0 •• • • . .... ..... ..... . .... . .... . .... ..... 0.0664 0.0830 0.0996 0. 1162 0.1328 0.1659 0.1991 0.2323 0. 2655 . .... . .... . .... • • 0 • 0 . .... . .... 0 •••• . .... ..... • 0 ••• . .... • • 0 •• . .... 0.0742 0.0978 0. 1114 0.1299 0.1485 0.1856 0.2228 0.2599 0.2970 0.3341 0 •••• 0 •••• ..... . .... . .... 0 •••• . .... . .... . ... . 0 0 ••• • 0 •• 0 . .... 0.0820 0. 1025 0. 123 0 0.1435 0. 1640 0.2050 0. 2460 0.2870 0.3280 0.3690 0.4100 0.4510 0 • • •• . . ... 0 •• 0 • • • 0 •• ..... ..... . .... . ... . . .... . . .. . 0.0976 0. 1220 0. 1464 0. 1708 0. 1953 0.2441 0. 2929 0.3417 0.3905 0.4393 0.4881 0.5369 0.5858 • 0 •• 0 • 0 ••• . .. .. 0 •••• . .... • 0 • • • . . . .. • 0 • •• • • •• 0 0. 1153 0. 1441 0.1729 0.2017 0.2305 0.2881 0.3458 0.4034 0.4610 0. 5186 0.5763 0.6339 0.6915 0. 7491 0.8068 . .... . .... • 0 •• 0 0. 1329 0. 1661 0. 1993 0.2325 0.2658 0.3322 0.3986 0.4651 0.5315 0.5979 0.6644 0. 7308 0.7973 0. 8637 0. 9301 1. 0630 AGO 5244A 383 Table XXXVI. Recommended Hole Sizes for Cold-driven Aluminum Alloy Rivets with Corresponding Shear and Bearing Areas Nominal rivet diameter (inches) 1/8 5/32 3/16 1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 Recommended hole diameter (inches) 0. 1285 0. 159 0.191 0.257 0.323 0. 386 0. 453 0. 516 0.578 0.641 0. 766 Corresponding drill size 30 21 11 F p w 29/64 33/64 37/64 41/64 49/64 Corresponding single shear area (square inches) 0.01296 0.01986 0.02865 0.05187 0.08194 0. 1170 0. 1612 0. 2091 0.2624 0.3227 0.4608 Bearing area for various sheet a nd plate thickness (square inches) 0.032 0.040 0.051 0.064 0. 081 0.102 1/8 5/32 3/16 7/32 1/4 5/16 3/8 7/16 1/2 9/16 5/8 11/16 3/4 13/16 7/8 1 0. 00411 0.00514 0.00655 0.00822 0.01041 0. 01311 0.01606 0.00509 0.00636 0. 00811 0.01018 0.01288 0.01622 0.01988 0.02480 0.00764 0.00974 0.01222 0.01547 0.01948 0.02388 0.02980 0.03581 0.04178 0. 01311 0. 01645 0.02082 0. 02621 0. 03213 0. 04016 0. 04819 0. 05622 0. 06425 0.0207 0. 0262 0.0329 0. 0404 0.0505 0.0606 0.0707 0.0808 0.1009 0.0313 0. 0394 0.0483 0.0603 0.0724 0.0844 0.0965 0. 1206 0.1448 0.0462 0.0566 0. 0708 0.0849 0.0991 0. 1133 0. 1416 0.1699 0. 1982 0.0645 0.0806 0.0968 0. 1129 0.1290 0. 1613 0.1935 0.2258 0.2580 0.0723 0.0903 0.1084 0. 1264 0. 1445 0.1806 0.2168 0.2529 0.2890 0. 325·1 0.0801 0.1002 0.1202 0. 1402 0. 1603 0.2003 0.2404 0. 2804 0. 3205 0. 3606 0.4006 0. 4407 0. 0958 0. 1197 0.1436 0. 1676 0.1915 0.2394 0. 2873 0. 3351 0. 3830 0.4309 0.4788 0.5266 0.5745 A GO 5244A Table XXXVII. Recommended Hole Sizes for""TYPe B Cadmium > Cl 0 Plated Self-tapping Screws (in Plastics) "" "' ... ... > Cellulose acetate cellulose nitrate Phenol acrylic resin formaldehyde styrene resin Minimum penetration Screw Hole Drill Hole Drill in blind diameter required size required size holes No. (inches) No. (inches) No . (inches) 2 0.078 47 0.078 47 3/16 4 0.099 39 0.093 42 1/4 6 0.128 30 0.120 31 1/4 7 0.136 29 0.128 30 1/4 8 0.149 25 0.144 27 5/16 10 0.177 16 0.169 18 5/16 12 0.199 8 0.191 11 3/8 14 0.234 15/64 inch 0.221 2 3/8 Note: Hex head screws not included in this table. Table XXXVlli. Recommended Hole Sizes for Types A and B Stainless Steel Self-tapping Screws (in Plywood, Resin Impregnated) Penetration in Minimum blind holes Screw Hole Drill material (inches) diameter required size thickness No. (inches) No. (inches) Minimum Maximum - 4 0.099 39 3/16 1/4 5/8 6 0.125 1/8 inch 3/16 1/4 . 5/8 8 0.144 27 3/16 1/4 3/4 10 0.173 17 1/4 5/16 1 14 0.228 1 5/16 3/8 1 Table XXXIX. Recommended Hole Sizes for TyPe A Cadmium Plated Self-tapping Screws (in Plywood, Resin Impregnated) Compreg and Pregwood Penetration in blind holes Minimum (inches) Screw Hole Drill material diameter required size thickness No. (inches) No. (inches) Minimum Maximum 4 0.098 40 3/16 1/4 3/4 3/4 6 0.110 35 3/16 1/4 7 0.128 30 1/4 5/16 3/4 8 0.140 28 1/4 5/16 3/4 10 0.169 18 5/16 3/8 1 12 0.189 12 5/16 3/8 1 14 0.228 1 7/16 1/2 1 388 AGO 5244A Screw diameter No. 4 6 7 8 10 12 14 Screw diameter No. 2 4 6 7 8 10 12 14 AGO 5244A Table XL. Recommended Hole Sizes for Type A Cadmium Plated Self-tapping Screws (in Asbestos Compositions) Transite and ebony asbestos Penetration in blind holes (inches) Minimum Hole Drill material required (inches) size No. thickness (inches) Minimum Maximum 0.093 42 3/16 1/4 3/4 0.106 36 3/16 1/4 3/4 0.125 1/8 inch 1/4 5/16 3/4 0.136 29 1/4 5/16 3/4 0.161 2."0 5/16 3/8 1 0.185 13 5/16 3/8 1 0.213 3 7/16 1/2 1 Table XLI. Recommended Hole Sizes for Type B Cadmium Plated Self-tapping Screws (in Castings, Nonferrous) Aluminum, magnesium and zinc Minimum penetration Hole Drill in blind required size holes (inches) No. (inches) 0.078 47 1/8 0.104 37 3/16 0.128 30 1/4 0.144 27 1/4 0.152 24 1/4 0.177 16 1/4 0.199 8 9/32 0.234 15/64 inch 5/16 389 Table XLII. Recommended Hole Sizes for Type B Cadmium Plated Self-tapping Screws (in Sheet Metal) Aluminum alloy - Pierced or extruded hole Screw diameter No. Metal thickness (inches) Hole required (inches) 2 0.015 0.018 0.024 0.030 0.036 0.048 0.060 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 0.015 0.018 0.024 0.030 0.036 0.048 0. 060 0.075 0.105 . . . . . . . . . . 0.086 0.086 0.086 0.086 . . . . . . . . . . . ~ . . . 6 0.015 0.018 0.024 0.030 0.036 0.048 0.060 0.075 0.105 0.128 to 0.250 . . . . . . . . . . 0.111 0.111 0.111 0.111 . . . . . . . " . . . . . . . . . . . . Drilled or cleanpunched hole Hole required (inches) . . . . . . . . . . 0.063 0.063 0.063 0.067 0.070 . . . . . . . . . . . . . . . 0.086 0.086 0.086 0.089 0.089 0.093 . . . . . . . . . . . . . . 0.104 0.104 0.104 0.106 0.110 0.111 0.120 Drill size No. 52 52 52 51 50 44 44 44 43 43 42 37 37 37 36 35 34 31 A GO 5244A Table XLII. Recommended Hole Sizes for Type B Cadmium Plated Self-tapping Screws (in Sheet Metal) (Cont) Aluminum alloy Screw Metal diameter thickness No. (inches) 7 0.018 0.024 0.030 0.036 0.048 0.060 0.075 0.105 0.128 to 0. 250 8 0.018 0.024 0.030 0.036 0.048 0.060 0.075 0.105 0.125 0.135 0.162 to 0. 375 Pierced or extruded hole Hole required (inches) . . . . . 0.120 0.120 0.120 0.120 . . . . . . . . . . . . . . . . . . . . . . . . . 0.136 0.136 0.136 0.136 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilled or cleanpunched hole Hole required (inches) . . . . . . . . . . 0.113 0.113 0.116 0.120 0.128 0.136 0.136 . .. . . . . . . . . 0.116 0.120 0.128 0.136 0.140 0.147 0.147 0.149 0.152 Drill size No. 33 33 32 31 30 29 29 32 31 30 29 28 26 26 25 24 AGO 5244A 391 Table XLII. Recommended Hole Sizes for Type B Cadmium Plated Self-tapping Screws (in Sheet Metal) (Cont) Aluminum alloy Screw Metal diameter thickness No. (inches) 10 0.018 0.024 0.030 0.036 0.048 0.060 0.075 0.105 0.125 0.135 0.164 0.200 to 0.375 12 0.024 0.030 0.036 0.048 0.060 0.075 0.105 0.125 0.135 0.164 0.200 to 0.375 Pierced or extruded hole Hole required (inches) . . . . . 0.157 0.157 0.157 0.157 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilled or cleanpunched hole Hole required (inches) . . . . . . . . . . . . . . 0.144 0.144 0.144 0.147 0.147 0.154 0.154 0.159 ' 0.166 . . . . . . . . . . . . . . 0.161 0.166 0.173 0.180 0.182 0.182 0.189 0.196 Drill size No. 27 27 27 26 26 23 23 21 19 20 19 17 15 14 14 12 9 392 AGO 5244A Table XLII. Recommended Hole Sizes for Type B Cadmium Plated Self-tapping Screws (in Sheet Metal) (Cont) Aluminum alloy Screw Metal diameter thickness No. (inches) 14 0.030 0.036 0.048 0.060 0.075 0.105 0.125 0.135 0.164 0.187 0.194 0.200 to 0.375 Pierced or extruded hole Hole required (inches) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilled or cleanpunched hole Hole Drill required size (inches) No. . . . . . 0.199 8 0.201 7 0.204 6 0.209 4 0.209 4 0.213 3 0.213 3 0.221 2 0.228 1 A GO 5244A 393 Table XLIII. Drill Sizes Lead hole size Hardwoods Softwoods Nearest Accurate Nearest Accurate Screw fractional drill fractional drill diameter size size size size No. (inches) No. (inches) No. 0 1/32 70 . . . . . 1 1/32 66 1/32 71 2 3/64 56 1/32 65 3 1/16 54 3/64 58 4 1/16 52 3/64 55 5 5/64 49 1/16 53 6 5/64 47 1/16 52 7 3/32 44 1/16 51 8 3/32 40 5/64 48 9 7/64 37 5/64 45 10 7/64 33 3/32 43 11 1/8 31 3/32 40 12 1/8 30 7/64 38 14 9/64 25 7/64 32 16 5/32 18 9/64 29 18 8/16 13 9/64 26 20 8/64 4 11/64 19 24 7/32 1 3/16 15 Note: Lead holes are not usually employed for No. 0 and No. 1 screws. For sizes less than No. 6, lead holes can be eliminated for softwoods, except near edges and ends of boards . AG O 5244A Table XLIV. Twist Drill Sizes Decimal Decimal Decimal Size equivalents Size equivalents Size equivalents 1/2 0.5000 c 0.2420 30 0.1285 31/64 0.4844 B 0.2380 1/8 0.1250 15/32 0.4687 15/64 o. 2344 31 0.1200 29/64 0.4531 A 0.2340 32 0.1160 7/16 0.4375 No. 1 0.2280 33 0.1130 27/64 0.4219 2 0.2210 34 0.1110 z 0.4130 7/32 0.2187 35 0.1100 13/32 0.4062 3 0.2130 7/64 0.1094 y 0.4040 4 0.2090 36 0.1065 X 0.3970 5 0.2055 37 0.1040 35/64 0.3906 6 0.2040 38 0.1015 w 0.3860 13/64 0.2031 39 0.0995 v 0.3770 7 0.2010 40 0.0980 3/8 0.3750 8 0.1990 41 0.0960 u 0.3680 9 0.1960 3/32 0.0937 23/64 0.3594 10 0.1935 42 0.0935 T 0.3580 11 0.1910 43 0.0890 s 0.3480 12 0.1890 44 0.0860 11/32 0.3437 3/16 0.1875 45 0.0820 R 0.3390 13 0.1850 46 0.0810 Q 0. 3320 14 0.1820 47 0.0785 21/64 p 0.3281 0.3230 15 16 0.1800 0.1770 5/64 48 0.0781 0.0760 0 0.3160 17 0.1730 49 0.0730 5/16 0.3125 11/64 0.1719 50 0.0700 N 0.3020 18 0.1695 51 0.0670 19/64 0.2969 19 0.1660 52 0.0635 M L 0.2950 0.2900 20 21 0.1610 0.1590 1/16 53 0.0625 0.0595 9/32 0.2812 22 0.1570 54 0.0550 K 0.2810 5/32 0.1562 55 0.0520 J I 0.2770 0.2720 23 24 0.1540 0.1520 3/64 56 0.0469 0.0465 H 0.2660 25 0.1495 57 0.0430 11/64 0.2656 26 0.1470 58 0.0420 G 0.2610 27 0.1440 59 0.0410 F 0.2570 9/64 0.1406 60 0.0400 E 1/4 0.2500 28 0.1405 D 0.2460 29 0.1360 AGO 5244A 395 ___j Table XLV. Common Material Specifications Lead Lead, peg -Federal Specification QQ-L-171 Lead, sheet -Federal Specification QQ-L-201 Welding Rod Rod, aluminum bronze welding-Military Specification MIL-R-18818 Rod, copper and copper alloy welding-Military Specification MIL-R-196318 Rod, copper and nickel alloy welding-Federal Specification QQ-R-571 Rod, steel and cast iron welding -Military Specification MIL-R-908 Rod, welding surfacing -Military Specification MIL-R-17131 Brazing Alloy Braze-welding -Military Specification MIL-B-12672 Brazing -Military Specification MIL-B-12673 Brazing alloy, copper, copper-zinc, and copper phosphorus -Federal Specification QQ-B-650 Brazing alloy, aluminum and magnesium -Federal Specification QQ-B-655 Brazing alloy, aluminum and aluminum alloys -Military Specification MIL-B-20148 Brazing alloy, silver-Military Specification MIL-B-15395 Zinc Plate Anodes, corrosion preventive -Military Specification MIL-A-18001 Pigment, zinc oxide -Federal Specification TT-P-463 AGO 5244). APPENDIX Ill DOCKING PLANS FOR STANDARD ARMY VESSELS 1. General Proper drydocking of Army vessels is accomplished by utilizing a drawing or docking plan of the particular vessel being docked. Docking plans show the various locations on the hull where blocking is required to support properly the vessel during the drydocking period. It normally consists of a longitudinal view of the vessel showing transverse bulkheads, framing, and sea conditions. Cross sections are shown at various points outlining the form of the hull. Depending upon the shape of the vessel, offsets can be indicated to facilitate setting bilge blocks and cribbing under docking keels. The docking plans shown in this manual are not intended to replace the standard docking plans issued for the vessels; they are to be used when drydocking the vessels listed in the absence of the standard docking plans. 2. Docking Plan Identification Docking plans listed in table XLVI are representative of the more commonly used Army vessels. AGO 5244A 397 ____. NOTE: ALL BLOCKING AND SHORING TO BE CLEAR OF THRU -HULL PENETRATIONS AND FITTINGS. TRANSVERSE BULKHEAD BLOCKING LONGITUDINAL BULKHEAD BLEEDER PLUGS ---e::~=====:=$'=:$===='tt BLEEDER PLUGS : :-= ; : r i · A lP 22 .5 15 FT 14 .I. 13 22.5 FT 12 11 10 I 9 30 FT I 8 I 7 I 6 2 2 . 5 FT I I 5 4 I 3 22. 5 I 2 FT I 1 I /FRAME STATION LINE FIP DETAIL A LOCATION OF BLEEDER PLUGS I i I I I I I I I I I ~ : I I I I ~~1' ' :-~:..__ _ _ _ I ---_ L -61 -6t-I ' 1 ' I • PROFILE-STARBOARD SIDE I I I I ~ SEE DET All A 1 . / 1 I · -............ .. __ _ _ -9-'-¥ I I I ~_:_,. ' ---... .rt-.----1----_. ______I_--_,_ 1.:t ____ I I -o-1-y-1·9-I ; : --_____!_,_ I 1 I I I i· TYPICAL BLOCKING AND SHORING PLAN VIEW Figure 270. Docking plan for barge deck ca1·go, nonpropelled, ocean towtng, 585 tons (BC), design 281-A. AGO 5244A 399 NOTE: ALL BLOCKING AND SHORING TO BE CLEAR OF THRU-HULL PENETRATIONS AND FITTINGS. PROFILE -STARBOARD SIDE BLOCKING BLOCKING SECTION AT FRAME 46 SECTION FRAME 5 THRU 40 Figure 271 . Docking plan for landing craft utility, 115ft (LCU-1466). AGO 524 4A -------~-- : ~ r --------------------1----------------------- 1 I I I I ld II Ti I DOCKING PLUGS~T --~---~~I -I t ,-k SHAFT"'-. -f;+j-j ---1 -~i~ : DETAIL A LOCATION OF DOCKING PLUGS BLOCKING TYPICAL SECTION Figure 281 . Docking plan for 1·epair shop, floating, marine equi1Jment, nonpropelled, design 7011 . AGO 52 44A 421 > C'l ..."" .... .... > n 0 z )> < m ~ :;10 m "' z ~ 0 c z -1 >< )> o::J < ,... m "' Table XLVI. Docking Plan Identification Vessel nomenclature Barge (BC), 120-foot Small tug (ST), 45-foot Passenger and cargo boat (T), 65-foot Small tug (ST), 65-foot Large tug (LT), 107-foot Picket boat (Q) , 65-foot Picket boat (J), 46-foot Floating repair shop (FMS) , 210-foot Liquid cargo vessel (Y), 222-foot Landing craft mechanized, 69-foot Landing craft utility, 115-foot Design Figure number 231-A 270 320 278 2001 272, 273 3004 274 3006 275 4002 276 4003 277 7011 281 7014 279 LCM-8 280 LCU-1466 271 424 AGO 5244A > () APPENDIX IV CONVERSION DBLES 1'0 "' .... .... > Table XLVII. English and Metric Equivalents Metric to English English to Metric Length 1 centimeter = 0. 3937 inch 1 inch = 2. 540 centimeters 1 meter = 3.281 feet 1 foot 0. 305 meter = 1 meter = 1. 094 yards 1 yard = 0. 914 meter 1 kilometer = 0. 621 statute mile 1 statute mile = 1.161 kilometers 1 kilometer 0. 5396 nautical mile = 1 nautical mile = 1. 853 kilometers Area 1 sq centimeter = 0.155 sq inch 1 sq inch = 6. 45 sq centimeters 1 sq meter = 10.76 sq feet 1 sq foot = 0. 0929 sq meter 1 sq meter = 1.196 sqyards 1 sq yard = 0. 836 sq meter 1 hectare = 2.47 acres 1 acre = 0. 405 hectare 1 sq kilometer = 0. 386 sq miles 1 sq mile 2. 59 sq kilometers Volume and Ca:Eacity 1 cu centimeter = 0. 0610 cu inch 1 cu inch = 16.39 cu centimeters 1 cu meter = 35.3 cu feet 1 cu foot = 0. 0283 cu meter 1 cu meter 1. 308 cu yards= 1 cu yard = 0. 765 cu meter 1 milliliter = 0. 0338 US liq ounce 1 US liq ounce = 29. 57 milliliters 1 liter = 1. 057 US liq quarts 1 US liq quart = 0. 946 liter 1 liter = 0. 2642 US liq gallon 1 US dry quart 1.101 liters = 1 liter = 0. 908 US dry quart 1 US liq gallon = 3. 785 liters 1 dekaliter = 1.135 US pecks 1 US peck = 0. 881 dekaliter 1 hectoliter = 2. 838 US bushels 1 US bushel = 0. 3524 hectoliter •..., 0. Table XLVII. English and Metric Equivalents (Cont) 1 gram 1 gram 1 kilogram 1 metric ton 1 metric ton 1 em/sec 1m/sec 1m/min 1 km/min 1 km/hour 1 km/hour 1 liter 1 liter 1 cu meter > Cl "' ... "' ... > Metric to -English English to Metric Weight = 15.43 grains 1 grain = 0.0648 gram = 0. 0353 ounce 1 ounce = 28.35 grams = 2. 205 pounds 1 pound = 0. 4536 kilogram = 0. 984 long ton llong ton = 1. 016 metric tons = 1.102 short tons 1 short ton = 0. 907 metric ton Linear velocity = 30.48 ft/sec 1ft/sec = 3. 281 x 10-2em/sec = 0. 3048 ft/sec 1ft/sec = 3.281 m/sec = 0. 3048 ft/min 1ft/min = 3.281 m/min = 2. 682 X 10-2mi/hr 1 mi/hr = 37. 28 km/min = 1.609 mi/hr 1 mi/hr = 0. 6214 km/hr 2 = 3. 088 x 10-knots 1 knot = 0. 5396 km/hr 1 knot = 0. 8684 mi/hr 1 mi/hr = 1.152 knots Liguid measure = 1. 0567 quarts 1 quart = 0. 9463 liter = 0. 2642 gallon 1 gallon = 3.7854 liters = 264.17 gallons 1 gallon = 0. 0038 cu meter Table XLVIII. Mariner's Measure 6ft = 1 fathom 120 fathoms = 1 cable length 6080.2 ft = 1 nautical mile 1 nautical mile per hr = 1 knot (speed) 1 degree at equator = 60 nautical miles 1 degree at equator = 69.17 statute miles Table XLIX. Mariner's Shipping Measure 1 register ton = 100 cu ft 1 US shipping ton or measurement ton = 40 cu ft = 32.14 US bu = 31.14 imp. bu 1 British shipping ton = 42 cu ft = 33.75 US bu = 32.17 imp. bu Table L. Mariner's Volume 1728 cu inches = 1 cu foot 27 cu feet = 1 cu yard 231 cu inches = 1 US gallon 5. 615 cu feet = 42 gallons = 1 barrel Table LI. Mariner's Avoirdupois Weight 437. 5 grains = 1 ounce 16 ounces or 7000 grains = 1 pound 2000 pounds = 1 short ton 2240 pounds = 1 long ton 35 cu feet of water = 1 ton Table LII. Mariner's Circular or~arMeasure 60 seconds = 1 minute 60 minutes = 1 degree 90 degrees = 1 quadrant or right angle 4 quadrants = 1 circumference AGO 5244 A 427 Table Llll. Weights of Materials Metals Pounds per cubic foot Aluminum, cast or hammered 165 Brass, cast or rolled 534 Copper, cast or rolled 556 Iron, gray cast 442 Lead 710 Mercury 849 Steel 489.6 Tin 459 Building Materials Concrete 144 Sand or gravel 100 to 120 Oak, white 46 Pine, white 26 AGO 52 ••A ~-------------------------------------------------------------------------- > 0 0 "" .... "" .... > Cubic feet 0.1 0.2 0.3 0.4 0.5 0.6 0. 7 0. 8 0. 9 1 2 3 4 5 6 7 8 9 10 20 30 40 Gallons 0.75 1. 50 2.24 2.99 3.74 4.49 5.24 5.98 6.73 7.48 14.96 22.44 29.92 37.40 44.88 52.36 59.84 67.32 74.81 149.6 224.4 299.2 Table LIV. U.S. Gallons in a Given Number of Cubic Feet (1 cubic foot= 7.4805195 U.S. Gallons) Cubic feet Gallons Cubic feet 50 374.0 9,000 60 448.8 10, 000 70 523.6 20,000 80 598.4 30,000 90 673.2 40,000 100 748.1 50,000 200 1,496.1 60,000 300 2,244.2 70,000 400 2,992.2 80,000 500 3, 740.3 90,000 600 4,488.3 100,000 700 5,236.4 200,000 800 5, 984.4 300,000 900 6, 732.5 400,000 1000 7,480.5 500,000 2000 14, 961.0 600,000 3000 22, 441. 6 700,000 4000 29,922.1 800,000 5000 37,402.6 900,000 6000 44,883.1 1,000,000 7000 52,363.6 2,000,000 8000 59,844.2 3, 000,000 Gallons 67,324.7 74,805.2 149,610.4 224,415.6 299,220.8 374,026.0 448, 831.2 523,636.4 598, 441.6 673,246.8 748,052.0 1.496.103.9 2,244,155.9 2, 992,207.8 3, 740,259.8 4, 488, 311. 7 5,236,363.7 5, 984,415.6 6, 732,467.6 7,480,519.5 14,961,039.0 22,441,558.5 ~ w Table LV. Cubic Feet in a Given Number of U.S. Gallons (1 U.S. gallon =231 cubic inches =0. 13368056 cubic foot) Gallons 1 2 3 4 5 6 7 8 9 10 20 40 60 80 100 200 300 400 500 600 > c;) • "' ... "' ... > Cubic feet 0.134 . 267 .401 . 535 . 668 • 802 . 936 1. 069 1. 203 1. 337 2.674 5.347 8.021 10.694 13,368 26.736 40.104 53.472 63.840 80.208 Gallons 700 800 900 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 Cubic feet 93.58 106.94 120.31 133.68 267.36 401.04 534.72 668.40 802, 08 935. 76 1, 069.44 1,203.13 1,336.81 2, 673.61 4,010.42 5,347.22 6,684.03 8, 020. 83 9,357.64 10,694.44 Gallons 90, 000 100, 000 200, 000 300,000 400,000 500, 000 600,000 700,000 800,000 900, 000 1,000, 000 2, 000, 000 3,000, 000 4, 000, 000 5, 000, 000 6,000, 000 7,000,000 8, 000,000 9,000,000 10,000,000 Cubic feet 12, 031. 3 13,398.1 26, 736. 1 40,104.2 53,472.2 66,840.3 80,208.3 93,576.4 106,944.4 120,312.5 133,680.6 267, 361. 1 401, 041.7 534,722.2 668,402.8 802,083.4 935, 763. 9 1,069,444.5 1,203,125.0 1,336, 805.6 Table LVI. Temperature Conversions OF oc OF oc oF oc OF oc OF oc -40 -40 70 21. 1 185 85. 950 510. 2100 1149. -35 -35.2 75 23.9 190 85.8 1000 537.8 2150 1176.5 -30 -34.4 80 26.7 195 90.6 1050 565.5 2200 1204. -25 -31. 7 85 29.4 200 93.3 1100 593. 2250 1232. -20 -28.9 90 32.2 205 96. 1 1150 621. 2300 1260. -15 -26. 1 95 35. 210 98.9 1200 648.5 2350 1287.5 -10 -23.3 100 37.8 212 100. 1250 676.5 2400 1315.5 -5 -20.6 105 40.6 215 101. 7 1300 704. 2450 1343. 0 -17.8 110 43.3 225 107.2 1350 732. 2500 1371. +5 -15. 115 46.1 250 121.2 1400 760. 2550 1399. 10 -12.2 120 48.9 300 148.9 1450 788. 2600 1426.5 15 -9.4 125 51. 7 350 176.7 1500 816 . 2650 1455. 20 -6.7 130 54.4 400 204.4 1550 844. 2700 1483. 25 -3.9 135 57.2 450 232.2 1600 872. 2750 1510. 30 -1. 1 140 60. 500 260. 1650 899. 2800 1537.5 32 0 145 62.8 550 287. 8 1700 926. 2850 1565. 35 + 1. 7 150 65.6 600 315.6 1750 954. 2900 1593. 40 4.4 155 68.3 650 343.3 1800 982. 295.0 1621. 45 7. 2 160 71. 1 700 371. 1 1850 1010. 3000 1648.5 50 10. 165 73. 9 750 398. 9 1900 1038. 3050 1676. 55 12: 8 170 76.7 800 426.7 1950 1065.5 3100 1705. 60 15.6 175 79.4 850 454.4 2000 1093. 3150 1732. 65 18.3 180 82.2 900 482.2 2050 1121. 3200 1760. To convert Fahrenheit into centigrade: Subtract 32 from Fahrenheit and divide remainder by 9 and multiply by 5. Example: 212°F 32 180 + 9 = 20. 20 X 5 = 100. 180 Answer: 2120 F = 1000 C To convert centigrade into Fahrenheit: Divide by 5, multiply by 9 and add 32. 0 Example: 260 C -T 5 = 52. 52 X 9 =468 + 32 =500°F Answer: 260°C -500°F AGO 5244A 431 Table LVII. Decimal Equivalents of Fractions Fraction 1/64 1/32 3/64 1/16 5/64 3/32 7/64 1/8 9/64 5/32 11/64 3/16 13/64 7/32 15/64 1/4 17/64 9/32 19/64 5/16 21/64 11/32 23/64 3/8 25/64 13/32 27/64 7/16 29/64 15/32 31/64 1/2 Decimal equivalent 0.015625 0.03125 0.046875 0.0625 0.078125 0.09375 o. 109375 0.1250 0.140625 0.15625 0. 171875 0.1875 0.203125 0.21875 0.234375 0.2500 0.265625 0.28125 0.296875 0.3125 0.328125 0.34375 0.359375 0. 3750 0.390625 0.40625 0.421875 0.4375 0.453125 0.46875 0. 484375 0.5000 Fraction 33/64 17/32 35/64 9/16 37/64 19/32 39/64 5/8 41/64 21/32 43/64 11/16 45/64 23/32 47/64 3/4 49/64 25/32 51/64 13/16 53/64 27/32 55/64 7/8 57/64 29/32 59/64 15/16 61/64 31/32 63/64 1 Decimal equivalent 0.515625 0.53125 0.546875 0.5625 0.578125 0. 59375 0.609375 0.6250 0.640625 0.65625 0. 671875 0.6875 0.703125 0. 71875 0.734375 0.7500 0.765625 0.78125 0.796875 0.8125 0.828125 0.84375 0. 859375 0.8750 0.890625 0.90625 0.921875 0.9375 0.953125 0.96875 0.984375 1 432 AGO 5244A GLOSSARY Abrid-A bushing plate around a hole in which a pintle works. Access hole-A hole through casing, bulkhead, floor, or deck to enable one to reach work or gear. Aces-Hooks for the chains. Ac01·n-A solid piece of metal shaped like an acorn and used to finish off the top of an upright in a railing constructed of pipe or a nut on the end of a threaded shaft. After peak-A compartment or tank located between the aftermost transverse bulkhead and stern frame. Afterrake-That part of the stern which overhangs the keel. Ahead-Forward of the bow. A ·i1· r-asing-The ring-shaped plate coaming around the stack below the umbrella and at the upper deck. It serves as an upper deck insulation and fireroom ventilation. Air chamber-An extension of the water piping beyond the branch to fixtures terminating with a cap. The compressed air in this portion of piping prevents any shock or vibration of pipe if faucet is closed suddenly. Altar-A step or a dry dock. Angle bar-A bar of angle-shaped section used as a stiffener and for attachment of one plate or shape to another. Aperture-The space provided for propeller between propeller and sternpost. Appendages-Relatively small portions of a vessel projecting beyond its main outline, as shown by cross sections and water sections. The work applies to the following parts of the stern and sternpost: the keel below its shell line; the rolling keel or fin; the rudder, rudder posts, screws, struts, bossing, bilge keel, and skeg. AGO 5244A ......., Apply template-A template to be used with another template and in a relative position indicated by pitch marks on both templates. Arch piece-The curved portion of the stern frame over the screw aperture, joining the propeller post and sternpost. A1·mstrong joint-A two-bolt, lugged or flanged connection for high pressure. Axis of a weld-A line through the length of a weld, perpendicular to the cross section at its center of gravity. Backhand welding-A gas-welding technique wherein the flame is directed opposite to the direction of welding. Backing weld-Backing in the form of a weld, deposited before a single-groove weld is made. Balanced frames-The midship frames that are of equal shape and square flanged. There are thirty or more on a cargo vessel, equally divided between starboard and port sides. Balanced rudder-A rudder, a portion of which is forward of the axis of rotation. Base Une-A horizontal le vel line at the lowest point of the mold lines and the top of the keel plate, on which all the calculations of the vessel's characteristics are based. B earding-The line of intersection of the plating and the stem or sternpost. Becket-A rope eye for the hook of a block; a rope grommet used in place of a rowlock. Bend-To make fast, such as bending a cable to an anchor; a knot used in joining two lines. Bilge blocks-The built-up wooden blocks at the bottom of a drydock upon which a vessel's bilge rests when in dock. Binding strake-A strake of planking fi·tted next to and under the sheer strake. 433 Bleeders-A term applied to plugs screwed into the bottom of a vessel to provide for drainage of the compartments when the vessel is in drydock. Blocking-A collective name for the wooden shores and blocks placed under a vessel's keel and bilges when on a building berth or in drydock. Also called cribbing, making up. Bolster plate-A plate adjoining the hawse hole to prevent the chafing of the hawser against the cheeks of a vessel's bow. Boot topping-Quick-drying anticorrosive paint used on and above the waterline. Bosom bar-An angle ,fitted inside another. Bosom plate-A plate, bar, or angle fitted in the bosom of two angle bars to connect the ends of the two angles as if by a butt strap. Boss-A thick section in a thin part, made to receive a bolt. It provides more material around the bolt than there would be normally in the thin body of the main piece in order to help transmit the loading on the craft into the thinner sections. Bonding bar-A bar connecting the edges of a bulkhead to tank top, shell, decks, or another bulkhead. Bower anchor-A heavy anchor carried in the forward part of the vessel and ordinarily used in anchoring. Bow painter-A line to the bow of a small craft used for securing it. Box girder-An assembly of plates used as a stiffener under decks. The form of the assembly is the same in cross section as the cross section of an H-beam. Box templates-Templates permanently fastened together, with two or more legs, of an angle iron or tee bar that ordinarily would be pitchmarked and applied separately; used where many angles or tee bars are to be duplicated. The inside of a box template fits the angle or tee bar for which it is made. Braze welding-A method of welding whereby a groove, filler, plug, or slot weld is made by using a nonferrous filler metal having melting point below that of the base metals but above 800°F ( 427 °C). The filler metal is not distributed in the joint by capillary attraction. Bronze welding, a term formerly used, is a misnomer. Breakwater-A low bulkhead forward to prevent seas from coming aft. A structure such as a seawall used for breaking the force of waves. Beaming-Cleaning such substances as barnacles and paint from a vessel's bottom with a blow torch. Breast-A mooring or docking line leading at an angle of about 90 ° with the fore-and-aft line of the vessel. Breast beam-The transverse beam nearest to midships on the poop and forecastle deck. B1·idging-A welding defect caused by inadequate penetration; a void at the root of the weld spanned by weld metal. Briggs standard-Standard pipe thread as used on threaded pipe in the United States. (See standard pipe.) Buildup sequence-The order in which t he weld beads of a multipass weld are deposit ed with respect to the cross section of a joint . Bulb plate-A narrow plate, generally of mild steel, rolled with a bulb or swell along one of its edges. Used for such purposes as hatch coamings and built-up beams. Buoy-A floating marker moored to the bottom which, by shape and color, conveys navi gational formation; also used for mooring vessels. Butt blocks-Blocks between frames, reinforcing a plank joint. Buttock line-An imaginary plane, cut vertically through the vessel from bow to stern; usually written in drawings titled BL. Butt straps-A term applied to a strip of plate serving as a connecting strap between the butted ends of plates. Calking recess-A counterbore or recess in the back of a flange into which lead can be calked for water, or copper for steam. Camber mold board-A board forming a pattern of one half the developed shape of the 434 AGO,,... deck of a vessel athwartships, the pattern showing the straight line or shape of the deck with the camber. The pattern shows one half the camber shape at the greatest half breadth of the deck. Cant beam--Any of the beams supporting the deck plating in the overhanging portion of the stern of a vessel. These beams radiate in fan shape from transom beam to cant frames. Capillary action-That property displayed by liquids when they extend beyond ·their natural limits through close-fitting surfaces. Examples of its operation are common: Ink spreads through a blotter when one corner touches a drop; oil rises in the wick of a lamp to the flame; and water is absorbed by a towel. In each of .these cases, close-fitting surfaces produce capillary action. In a solder joint, the valve or fitting end and the copper tubing are the close-fitting surfaces. Capping-A fore-and-aft finishing piece on top of the clamp and sheer strake and at the frame heads in an open craft; called a covering board or margin plank, or planksheer, in a decked-over craft. Cargo battens-Planks used to hold cargo away from bulkheads and vessel's sides. Carvel-built-Constructed with planks meeting flush at the seams or a type of plating made flush at the seams or a type of plating made flush by vee butt welding or butt strap riveting. Catalyst-A chemical which causes atomic reaction of plastics and activates polymerization or cure. Different plastics require different catalysts. Cellular double bottom--A term applied where the double bottom is divided into numerous rectangular compartments by the floors and longitudinals. Centrifugal trap-A trap so constructed to give the water, when passing through it, a whirling motion, thereby making the trap selfcleaning. Chafing gear-A guard of canvas or line around spars, hawsers, chocks, or rigging to prevent chafing. AGO 5244A Chafing mat-A mat woven from strands of old rope and used to prevent chafing. Chafing plate-A bent plate used in minimizing chafing of ropes, as at hatches. Chain locker pipe-The iron bound opening or section of pipe leading from the chain locker to the deck, through which the chain cable passes. Chain pipe-A pipe of large diameter, through which the chains pass into the chain lockers. Chain plcdes-Piates of iron bolted to the side of a craft, to which the chains of the lower rigging are connected. Chain stopper-A device which prevents anchor chain from running. It is moved into position after the anchor has been dropped. Cha-in tongs-A pipefitter's tool; a lever with a serrated end provided with a chain to enlace the pipe. The chain is wrapped around the pipe to hold the lever in place, and the teeth on the end of the lever grip into the pipe, thus affording a powerful leverage to screw or unscrew the joints. Chalk line-A small line, strong enough to withstand being drawn very taught over a surface. The line is first chalked, then drawn taught between two points and snapped, thus leaving an impression of the chalk on the surface to be marked. Chase-A recess in wall in which soil, vent, and waste stacks or similiar piping is installed. Chase joint-A kind of plate joint by which an overlap can gradually be made flush. This is done with the aid of liners and is used on the bow and stern to give the vessel a finer trim. Circular weld-A weld extending around a girth seam. Such welds are sometimes butted and often are_scarfed. Clinching-Bending over or blunting and bending over protruding points. Clinch pan-Steel plate with handle against which to blunt and clinch tacks or nails. Coalescence-In welding, the growing together or union of weld and base metals. Coaming-The raised framework about deck openings and cockpits of open vessels. Cofferdam-Space between two bulkheads set close together, especially between fuel oil tanks and potable water tanks. Cold shut-A welding defect due to the cooling of the weld metal before fusion is completed. Collision bulkheadr-A watertight athwartship bulkhead a short distance abaft the bow for the purpose of confining damage due to a head-on collision. Collision mat-A heavy square of canvas hauled under the side as a temporary plug for a leak or shell hole. Complete fusion-Fusion that has occurred over the entire base-metal surfaces exposed for welding. Composite joint-A joint where welding is used in conjunction with a mechanical joining process. Concurrent heating-The application of supplemental heat to a structure during a welding or cutting operation. Contraction-The shrinkage of metal due to cooling from an elevated temperature. Conventional paints-Linseed oil, alkyd, phenolic, coal tar, and other common resin paint. Vinyl, epoxy, and urethane are not considered conventional paints. CTibbing-Timber used to support the bottom of a vessel while it is under construction or in drydock. Cup joint-A joint used on lead pipe, made by opening end of pipe enough to receive the tapered end of another piece. Deadlight-A fixed glass in a bulkhead for admitting light and permi1tting vision; also a cover for a port light to prevent interior light from being seen from the exterior. Deck line-The line from forward to aft where a deck touches the vessel's side. Depth of fusion-The distance that fusion extends into the base metal from the surface melted during welding. Devil's claw-A strong iron hook used as a stopper for chain cable. Die welding-A forge-welding process where coalescence is produced by heating in a furnace and by dies. Dip brazing-A brar.ing process where coalescence is produced by heating in a molten chemical or metal bath and by using a nonferrous filler metal having a melting point above 800 ° F ( 427° C), but below that of the base metals. The filler metal is distributed in the joint by capillary attraction. When a metal bath is used, the bath provides the filler metal. Dog-A type of bolt nut used to secure watertight doors, hatch covers, and manhole covers; also metal rods which are driven into blocks at the bottom of a drydock ~to prevent them from floating. Double bend-A pipe or fitting shaped like the letter S in outline. Doubling pl£Lte-An extra plate of the same strength or stronger than the original plating, secured to the original plating for additional strength. Downhand-(See Flat position.) Draft (draught)-The depth of water from the surface to the vessel's keel. Dresser joint-A peculiar form of Normandy joint. Drift pin-A pin used for enlarging rivet holes, forcing holes into alignment, and driving out pins and keys. Driftedr-Having had a drift or short mandrel passed through the pipe in order to be certain that there are no inside irregularities or that they have thereby been removed. It is also, but less correctly, called plugged. Dummy fitting-A temporary substitute for such fittings as elbows, tees, Y's ( wyes), and manifolds. Eccentr·ic fitting-A fitting having its opening on centerlines that are not concentric, usually arranged so that the interior walls of one side are in one plane; so arranged for draining condensation. AGO 5244A , Electrolyte-A· solution of sulphuric acid and distilled water, normally with a specific gravity of 1,300 and used in storage batteries. Epoxy-A liquid plastic which will cure at room temperatures when activated with a suitable catalyst. It is nonshrinking and has outstanding adhesive and other properties, but some epoxies are toxic to handle. Etch test-A method of testing the soundness of welds. Fairing a line-Straightening lines supposed to be straight; or smoothing out, into a smooth curve, lines supposed to be curved. Fal~The line used to lower and hoist a boat at the davits. False kee~A thin covering secured to the lower side of the main keel of vessels to afford protection. Ferrules-Insulated packing, rolled and glued together, and inserted in bolt holes of insulated deck or bulkhead connections that will connect to steam lines to prevent conduction of heat from the pipe line to the deck. Fi fty-fifty solder-Solder made up of half lead and half tin. Fille1· block--Solid pieces of material, as wood or metal, used to strengthen or sustain. Fillet-A term applied to the metal •filling in the bosom or concave corners where abrupt changes in direction occur in the surface of a casting, forging, or welding. Flame hardening-A method for hardening a steel surface by heating followed by suitable quench. Flame softening-A method for softening steel by heating with a gas flame and slow cooling. Flare-The outward and upward curve in the form of a vessel's bow; the curve of a vessel's bottom from the waterline to the keel. Flash plate-Protective metal plate secured to the deck over which the anchor chain rides. Flash welding-A resistance-welding process where coalescence is produced simultaneously, over the entire area of abutting surfaces, by the heat obtained from resistance to the flow of current between two surfaces and by the application of pressure after heating is substantially completed. Flashing is accompanied by expulsion of metal from the joint. Flexitallic joint-A special gasket, made up of special metals with a series of spiral turns, between which asbestos paper is inserted. When this gasket is tightened between the flange faces, it is compressed, thereby insuring a tight semimetallic joint. It is used on raised-face flanges for high pressure piping. Flow brazing-A brazing process where coalescence is produced by heating with molten nonferrous filler metal poured over the joint until brazing temperature is attained. The filler metal has a melting point about 800 °F ( 427 °C), but below that of the base metals, and is distributed in the joint by capillary attraction. Flow welding-A welding process where coalescence is produced by heating with molten filler metal poured over the surfaces to be welded until the welding temperature is attained and until the required filler metal has been added. The filler metal is not distributed in the joint by capillary attraction. (Burning-in, formerly used, is a misnom.er for this term.) Flux-A fusible material us ed in welding and oxygen cutting to dissolve and facilitate removal of oxides and other undesirable substances. Flux-o xygen cutting-An oxygen-cutting process where severing of metals is effected by using a flux to facilitate the cutting. Forge welding-A group of welding processes where coalescence is produced by heating in a forge or furnace and by applying pressure or blows; sometimes called blacksmith welding. Form stringers-Temporary stringers which, as part of the vessel mold, give longitudinal form to the vessel; stringers which are not part of the craft, but which are considered part, for the purpose of forming the shape. Fou~A term applied to the underwater portion of the outside of a vessel's shell when it AGO 5244A 437 is more or less covered with sea growth or other foreign matter. Freeboard-The distance from the water line to main deck. Freeing ports-Holes in the lower portion of a bulwark which allow deck wash to drain off into the sea. Some freeing ports have swing gates which allow water to drain off but which are automatically closed by seawater pressure. Furrings-Strips of timbers or boards fastened to frames and joists in order to bring their faces to the required shape or level for attachment of sheathing, ceiling, and flooring. Galling-Tearing threads when cutting. Gas pocket-A weld cavity caused by entrapped gas. Gas welding-A group of welding processes where coalescence is produced by heating with a gas flame or flames, with or without the application of pressure and with or without the use of filler metal. Gib-A metal fitting that holds a member in place or presses two members together. Girth-The distance measured on any frame line, from the intersection of the upper dec'k with the side around the body of the vessel to the corresponding point on the opposite side. Gooseneck-An iron hook secured to the inner end of a boom having no jaws and fitting into an iron eye carried on the mast. Grating-A wooden latticework platform covering a hatch or the bottom boards of a craft; similarly designed grating of metal is frequently found on a vessel. Grommet-A ring of line made from a single strand; also from rings sewed into the edge of a hammock or hatch covering. Gudgeo'Ylr-Lugs cast or forged on the sternpost for the purpose of hanging the rudder. Each lug is bored to form a bearing for a rudder pintle. Gunwale-The upper edge or rail of a vessel's or craft's side. Gunwale bar-A term applied to an angle bar connecting a stringer plate on a weather deck to the sheer strake. Gusset-A bracket or angular piece of material which strengthens angles. Gusset plate-A horizontal bracket plate used for fastening posts, frames, and beams to other objects. Hal[-bTeadth pla'Ylr-A plan of one half a vessel divided by a centerline drawn through the stem and stern posts. It shows the water, bow, and buttock lines. Half-hole joint-A modification of the full gasket and the ring joint. It fits the gasket face and extends out to the pitch circle of the bolt holes, which means that it covers one half the bolt holes. Hamme1· welding-A forge-welding process where coalescence is produced by heating in a forge or furnace and applying pressure by using hammer blows. Hard patch-A plate riveted over another plate to cover a hole or break. Harpings-The fore parts of the wales of a vessel which encompass its bows and are fastened to the stem, thickened to withstand plunging. Hatch coaming-A frame bounding a hatch for the purpose of stiffening the edges of the opening and forming the support for the covers. In a steel vessel, it generally consists of a strake of strong vertical plating completely bounding the edges of a deck opening. Hawse-That part of a vessel's bow in which the hawse holes for the anchor chains are. Heat-affected zone-That portion of the base metal which has not been melted, but whose mechanical properties or microstructures have been alerted by the heat of welding or cutting. Heat time-In multi-impulse welding or seam welding, the time that the current flows during any one impulse. Helm-A term applied to the tiller, wheel, or steering gear and also to the rudder. AGO 5244A Helm PO't't-The hole in the counter of a vessel through which the rudder stock passes. Hog frame-A fore-and-aft frame, forming a truss for the main frames of a vessel to prevent bending. Hogging-The distortion of a vessel's hull when its ends drop below normal position relative to midship portion. Holiday-Parts of a vessel's surface which have been accidentally missed during painting or other protective processing. Horn-In resistance welding, a beam or arm, extending from the frame of a welding machine, which transmits the electrode force and usually conducts the welding current. Horseshoe plate-A small, light plate fitted on the counter around the rudder stock for the purpose of preventing water from backing up into the rudder trunk. Frequently it is made in two pieces. Hounding-That portion of a mast between the deck and the hounds. Hounds-The mast head projections which support the trestle trees and top; also appplied in vessels without trestle trees to that portion at which the hound band for attaching the shrouds is fitted. Induction brazing-A brazing process where coalescence is produced by the heat obtained from resistance of the work to the flow of induced current and by using a nonferrous fille;:· metal with a melting point above 800 ° F ( 427 °C), but below that of the base metals. The filler metal is distributed in the joint by cap-mary attraction. Induction welding-A welding process where coalescence is produced by heat obtained from resistance of the work to the flow of induced electric current, with or without the application of pressure. Inert-gas carbon-arc welding-An arc-welding process where coalescence is produced by heating and the work. Shielding is obtained from an inert gas such as argon or helium. Pressure may or may not be used and filler metal may or may not be used. Inert gases-Argon and helium. AGO 5244A -, Insert plate-A heavier plate installed in a hole cut to shape, used for added strength. Inside strake-A strake having edges which are overlapped by those of the outside strakes. Intermediate beams-Beams placed between deck beams, if the spacing of the latter is unusually large. Intermediate frames-Frames placed between main frames, if the spacing of the latter is unusually large, Jacob's ladder-A ladder of rope with rungs used over the side and aloft. Joggling-The term applied to offsetting one plate edge of a lapped plate joint, to give a continuous flush surface on the side opposite the offset; also, the term applied to offsetting one frame in way of an outside strake of plating to make both outside and inside strakes fit snugly against the frame. Joggling is employed to eliminate the use of liners. Journa~That portion of a shaft or other revolving member which transmits weight directly to and is in immediate contact with the bearing in which it turns. Jury-A term applied to temporary structures, such as masts and rudders, used in an emergency. Keelson-A fore-and-aft vertical grider on top of a keel used to strength the vessel's structure. Kentledge-Pig iron used either as temporary weight for inclining a vessel or as a permanent ballast. King posts-The main pillar posts of the vessel; also called samson post; a post or pillar forming support for a cargo boom. Knee-An angular piece connecting a vessel's frames to the beams. Knee beam-A bracket between a frame or stiffener at the end of a beam; a beam arm. Landing-The distance from the edge of a plate or bar to the center of the first rivet hole. Lap-A joint in which one part overlaps the other, thus avoiding the use of a butt strap. 439 Lap weld-Method of making steel or wroughtiron pipe in which the edges of the sheet are beveled and lapped before welding. Lazarette-A low head-room space below decks, in the after part of some vessels, used for provisions or spare pal1ts. Lazy guy-A light rope or tackle by which a boom is prevented from swinging around. Lead wool--Lead in a shredded form used to calk cast-iron pipe where the moisture prevents the use of molten lead. Lifting pads-Pads or eyelet plates permanently attached outside the shell in position for anchoring rigging to hoist the rudder or propeller or to lash the rudder fast. Lightening holes-Holes of various sizes cut in a plate to make it lighter and yet not reduce its strength. Light load line-The waterline when the vessel rides empty. Load waterline-The line painted on the side of a vessel representing the intersection of the vessel's form with the plane of the water's surface when floating with her designed load on board; also applied to the actual intersection of the surface of the water with a vessel's side. Local preheating-Preheating a specific portion of a structure. Lock-bibb-A bibb or faucet so constructed as to allow the use of a padlock to prevent its being opened. Lock-stop-A stop cock so constructed as to allow the use of a padlock to keep it opened. Machinery compartment-All boiler rooms, engine rooms, and compartments for auxiliary engines are classified as machinery compartments. Mainmast-The second mast from the bow of a vessel having two or more masts. If avessel has but one mast, it is considered the mainmast. Malleable iror~r--Cast iron made from pig iron of the proper kind, so treated to render it capable of being bent or hammered to a limited extent without breaking; that is, it is malleable. Its strength is above that of cast iron. The process is known as annealing. Manger-The perforated, elevated bottom of the chain locker which prevents the chains from touching the main locker bottom and allows seepage water to flow to the drains. Marine glue-A substance resembling guttapercha and sometimes used in calking decks as a substitute for pitch. Marine railway cradle-The carriage on which the vessel rests when being docked on a marine railway. Marine ways-A carriage on rollers on a track which runs into the water. It is used as a cradle for pulling a vessel on land. Marlinespike-A pointed iron instrument used in splicing line and wire. Master die-A die made standard and used only for reference purposes or for treading taps. Master tap-A tap cut to standard dimensions and used only for reference purposes or for tapping master dies. Masthead-The top of a mast. Matheson and Dresser joint-A combination joint in which a Dresser leak clamp of special advantage is that it allows repair without shutting off the service pressure; much used on pipes 16-inch outside diameter and less. Matheson joint-A wrought pipe joint made by enlarging one end of the pipe to form a suitable lead recess, similar to the bell end of a cast-iron pipe, and which receives the male or spigot end of the next length; practically the same style of joint as used for castiron pipe. Medium pressure-When applied to valves and fittings, a good working pressure of 125 to 175 pounds per square inch. Melting rate-The weight or length of electrode melted in a unit of time. Metacentric height (GM)-The distance between the center of gravity ( CG) of the vessel and the metacenter, either transverse or longitudinal, of a floating body. AGO 5244A Metal-electrode and arc welding-A group of arc-welding processes where metal electrodes are used. Microballons-Very thin, hollow plastic spheres, used as a fill putty when mixed with plastic. Midship coefficient-The ratio of the area of the immersed midship section of the vessel to the area of the circumscribing rectangle. MiTr-A small angle equal to 3.44 minutes, or 1 yard across the line-of-sight for each 1,000 yards of range. Mil thickness-The dry film thickness of a paint coat. Each mil equals one-thousandth of an inch. Mixer chamber-That part of gas-welding or oxygen-cutting torch wherein the gases are mixed. Mock moldr-A metal form on or in which an object can be hammered or pressed to give the object proper shape. Molded beam-The width of widest portion of a vessel measured to outside the frame angle or channel inside the plating. Mold ed breat~The greatest breadth of the vessel measured from heel of frame on one side to heel of frame on other side. Molded dept~The extreme height of a vessel amidships from the top of the keel to the top of the main deck. Molded line-A datum line from which is determined the exact location of the various parts of a vessel. It can be horizontal and straight as the molded base line, curred as a molded deck line, or a molded frame line. These lines are determined in the design of the vessel and adhered to throughout the construction. Mold lines are laid down in the mold loft. Mold forms-Forms made to the shapes of the section drawings of the lines of vessel; used to shape the hull. Molding edge-The edge of a vessel's frame which comes in contact with the skin and is represented in the drawings. Mold loft-The large enclosed floor where the lines of a vessel are laid out and the molds or templates made. Moments to (alter) trim 1 inc~Number of foot-pounds (tons) to alter the difference between forward and after draft of the craft by 1 inch. Monkey tailr-A curved bar fitted to the upper, afterend of a rudder and used as an attachment for the rudder pendants. Monomer-A cross-linking molecule which helps the plastic to polymerize. Polyester resin is made of a polymer and a monomer and the polymer and the monomer can be made from different base materials; hence the great differences in polyester resins. Mortise-A hole cut in any material to receive the end or tenons of another piece. Multi-impulse welding-The making of spot, projection, and upset welds by more than one impulse of current. When alternating current is used, each impulse can consist of a fraction of a cycle or number of cycles. Mult·i-impulse weld tim er-In resistance welding, a device for multi-impulse welding which controls only the heat time, cool time, and either the weld interval or the number of heat times. Mushroom ventilator-A ventilator cowlshaped like a mushroom. Nonfe1·rous-Containing no iron. Copper, brass, aluminum, and lead are nonferrous metals. Norman--A pin through the head of a bollard to prevent hawsers from slipping off. Nugget-The weld metal joining the parts in spot, seam, or projection welds. Oakum-A calking material made of old tarred hemp rope fiber. Offset--A table of molded dimensions for waterlines and decks; to bend out of line sharply. Outboard profile-A plan representing the longitudinal exterior of a vessel, showing a side of the shell, all deck erections, masts, yards, riggings, and rails. AGO 5244A 441 Outer skin-The outside plating of a vessel. Packing-A general term applied to yield material used to make a tight joint. Pad eye-A metal eye permanently secured to a deck or bulkhead. Panting-The pulsation in and out of the bow and stern plating as the vessel alternately rises and plunges into the water. Panting beams-The transverse beams that tie the panting frames together. Panting f-rames-The frames in the forepeak, usually extra heavy to withstand the panting action of the shell plating. Panting stringer-A horizontal stiffener with a breast hook, giving added strength against panting. Pawlr-The catch which stops, falls or holds to a ratchet wheel. Pelican hook-A hinged hook which is held in place by a ring; when the ring is knocked off, the hook swings open. Pet cock-A small cock used to drain a cylinder or fitting. P'intles-Pivot pins on which a rudder turns. Pipe dog-A hand tool that is much used to rotate a pipe whose end is accessible. It is simply a small, short steel bar whose end is bent at right angles to the handle, and then quickly returned, leaving only enough space between the jaws to slip over the wall of the pipe. Pipe fittings-Connections, appliances, and adjuncts, designed to be used in connection with pipes, such as elbows and bends, to alter the direction of a pipe; tees and crosses to connect a branch with a main; plugs and caps to close an end; bushings, diminishers, or reducing sockets to couple two pipes of different dimensions. Pipe hanger-A suspension link or band (often split), used to support a pipe without interfering with its expansion and contraction. Pitch--The distance advanced by a propeller in one revolution; the distance between the centers of the teeth of a gear and spacing of rivets. Planking-Broad planks used to cover a wooden vessel's sides ; a covering f or deck beams. Platen-A part of a resistance welding machine with a substantially fiat surface to which dies, fixtures, backups, or electrodes are attached and which transmits the electrode force or upsetting force. A fiat surface provided for assembling units of a vessel. Platen force-The force available in flash and upset welding at the movable platen to cause upsetting. This force can be dynamic, theoretical, or static. Plimsoll mark-A mark painted on the sides of a vessel designating the depth to which the vessel can, under the maritime law, be loaded in different bodies of water during various seasons of the year. Polyester-A liquid plastic, commonly used for laminating fiberglass crafts. It cures at room temperature when a catalyst is added. Pontoon-A portable tank used to give buoyancy. Poppets-Pieces of timber which are fixed perpendicularly between the vessel's bottom and the bilgeways at the foremost and aftermost parts of the vessel to support it when being launched. Pressure welding-Any welding process or method where pressure is used to complete the weld. Preventer-A line used for additional safety and to prevent loss of gear under heavy strain. Prick punch--A small hand punch used to make a very small indentation or prick in a piece of metal. Propeller arch--The arched section of the hull above the propeller. Protective deck-The deck fitted with the heaviest protective plating. Protector-A ring threaded on its inside and used to protect the threaded end of pipe in transit. 442 AGO 6244A Pump dale-A pipe to convey water from the pump discharge through the vessel's side. Purchase-A tackle consisting of blocks and falls. Quadrant-The metal fitting on the rubber head of a vessel to which the steering ropes are attached. Quay-An artificial wall or bank, usually of stone, made toward the sea at the side of a harbor or river for convenience in loading and unloading vessels. Rabbet-That part of a structural member recessed to accommodate other structural members. Rabbet stringer-A beam or timber which runs fore and aft at the garboard or rabbet line for the purpose of stiffening the hull. Radius of bend-The distance measured always from the center of curvature to the center of pipe or fitting. The relation between length of radius and size of pipe is modified by the ratio of the pipe's thickness to its diameter; in general, the thinner the pipe, the longer the radius. Rail-A guard made of flat pieces of wood or of steel bars or rods joined and connected to the upper edge of the bulwark plating, or fitted upon the summits of stanchions sur rounding an upper deck, bridge, poop, or forecastle. Railroad chalk-White and blue chalk supplied in rvund bars about 1 inch in diameter and 4 inches long; a fine-grained grade of chalk pressed into a very hard stick. Rail stanchions-Iron stanchions, about 3 feet high, fitted with several tiers of guard ropes or chains, to enclose the sides and ends of a bridge, forecastle, or poop, and sometimes an upper deck. Rake-The inclination of a vessel's mast, funnel, or stem, from its upright angle with the keel. The rake can be either forward or aft. Rat guard-A circular piece of metal made in two parts and fitted closely on hawsers and lines to prevent rats boarding a vessel while at a dock or wharf. Ratline-One of the small transverse ropes attached to the shrouds and forming a rope ladder. R eaction stress-The residual stress which cannot otherwise exist if the members or parts being welded are isolated as free bodies without connection to other parts of the structure. R ef erence line-A line fixed in position and location from which measurements are made. R egiste1·ed breadth-Measured amidships at its greatest breadth to outside of plating. R elief-Any clearance allowed back of the cutting edge to reduce friction, whether on top, bottom, or wall of the thread. R esidual stress-Stress remaining in a structure or member as a result of thermal or mechanical treatment, or both. R eturn bend-A 180° bend; usually a fitting having inside threads ; often applied to a bent pipe; always means the fitting unless otherwise specified. R everse frame-An angle bar or other shape riveted to the inner edge of a transverse frame to reinforce it. Ribband-Strips of material temporarily holding par ts of a vessel in position. Ri bs--The frames of a vessel to which the sides are secured. Rider frame-Any frame riveted or welded on another frame for the purpose of stiffening it. Rider plate-A continuous flat plate attached to the top of a centerline vertical keel in a horizontal position. Its underside is attached to the floors and, when an inned bottom is fitted, it forms the center strake. Rising floors-The floor frames which rise fore and aft above the level of the midship section. River dog-A device to hold a pipe line on a river bottom. River sleeve-A long sleeve used over other joints to prevent injury to joints laid on river bottom or under water. An excellent form requires sleeves to be about 6 diameters AGO 5244A 443 long and fit as neatly as possible to the outside of the central joint. It is so made to prevent bending or springing of the pipe, which might injure or loosen the joint. Riveting chai'Yir-Two or more rows of rivets that have their centers opposite each other. Root crack--A crack in the weld on base metal occurring at the root of the weld. Root f ace-That portion of the groove face adjacent to the root of the joint and parallel to the root face of the other member. Runner-Shape or flanged plate at end of treads and risers on a stairway; longitudinal member making up a template. Samson post-A heavy vertical post that supports cargo booms located between the centerline and bulwarks; also known as a king post. S cantlings-A term applied to the dimensions of the frames, griders, and plating that enter into a vessel's structure. Scoop-Through-hull fitting that permits water to flow into or out of plumbing systems within the vessel. S creen bulkheadr-A light bulkhead fitted between engine and boiler rooms, used to keep dust and heat out of the engine room; often built around the afterends of boilers. S cribe-To mark; to mark with a tool; to mark a line with a draftsman's compass by drawing the pointer along the edge of a similar part. Scrieve-To mark by cutting-in with pencil or knife for permanence. S crieve board-A large section of low flooring in the mold loft in which the lines of the body are cut with a knife; used in making molds of the frames, beams, and floor plates. Scupper casting-An opening cut through the waterway and bulwarks of a vessel so that water falling on deck can flow overboard. This casting is secured under the opening cut in the waterway. S cupper hose-A temporary canvas hose attached to the outside of a scupper hole and reaching to the water, to conduct the water clear of the vessel's side. ScuJJper lip-A projection on the outside of the vessel to allow the water to drop free of the vessel's side. Scuppers-Drains from decks to carry off accumulations of rain water or sea water. The scuppers are placed in the gutters or waterways on open decks and in corners of enclosed decks and connect to pipes leading overboard. Scuttle-A small opening, usually circular in shape and generally fitted in decks to provide access, as a manhole, or to stow fuel, water, and stores. Sea chest-A compartment through which sea water is admitted or discharged. S eacock--A cock in a pipe connected to the sea; a vessel can be flooded by opening the seacocks. Seam battens-Wood seam straps which connect the edges of small vessels having a single thickness of planking, give additional stiffness to the planks, are continuous, and have notched out to fit over them. Seam welding-A resistance-welding process where coalescence is produced by the heat obtained from the resistance to the flow of electric current through the work parts held together under pressure by circular electrodes. The resulting weld is a series of overlapping spot welds made progessively along a joint by rotating the electrodes. S ellers threadr-The standard screw thread of the United States, having an angle of 60° between the threads, and one-eighth flattened at top and at bottom. It is also known as United States Standard Thread and as the Franklin Institute Standard Thread. Series welding-The making of two spot welds or seam welds or two or more projection welds simultaneously with three electrodes forming a series circuit. S ervice ellr-An elbow at 45° or 90 ° having male threads on one end and female on the other; also called a street ell. AGO 524 4A Service tee-A tee having male threads on one end and female on the other end and the branch; also called a street tee. Set (of a frame)-The distance between the chord of the portion of the frame line concerned and the frame line, measured at the point where the distance is greatest. Set bolt-A bolt used as a drift to force another bolt out of its hole. S et ir o'Yir---Bar of soft iron used on the bending slab to bend frames to desired shapes. Shave hook-A small scraper used by lead workers to scrape lead pipes prior to soldering. Shear ma1·k-A mark or symbol used to indicate where a cut is to be made. Sheer-The longitudinal curve of a vessel's rails and decks, the usual reference being to the vessel's side; however, in the case of a deck having a camber, its centerline can also have a sheer. Sheer height-Height of decks or flats at frames, measured from base line. Sheer pla'Yir---Side elevation of vessel's form. Sheer railr-A rail surrounding a vessel on the outside under the gunwale; on small vessels called guardrail. Sheer strike-The upper strake of the main shell plating just below the bulwarks. Sheet separatio'Yir---ln spot, seam, and projection welding, the gap surrounding the weld betwen faying surfaces after the joint has been welded. Shellr-Outside covering of the vessel, exclusive of decks and superstructure. Sherardizing-A process in which clean surface of iron or steel is coated with zinc-iron alloy for protection against rust. Shifting beam-A portable beam fitted in a hatchway for the purpose of supporting the hatch covers. The ends of the beams are fitted in slotted carriers attached to the inside of hatchway coamings. Shift of butts-An arrangement of butts in longitudinal or transverse structural mem- AGO 6244A bers whereby the butts of adjacent members are located a specified distance from each other, measured in the line of the members. Shoe~A blacksmithed shape forming the bend of a bulkhead bounding bar over the stringer bar of deck or tank top to shell. Shole-A piece of plank put under a shore where there is no groundway. Shore-One of the many wooden props by which the ribs or frames of a vessel are externally supported while building or by which the ribs or frames of a vessel are externaly supported while building or by which the vessel is held upright on the ways. Sh1·oud-Side stay of hemp or wire running from the masthead to the rail to give support to the mast. Shroud pads-Devices for attaching shrouds or guy cables to crosstree or bulwark. S'ide frames-Frames in the side above and connecting with the tank top margin plates. Sister frame-A frame installed during repair to relieve stress from an existing frame that is broken or damaged. Sister hooks-Two iron flatsided hooks, reversed to each other, suspended from a thimble with the flat sides together when in place. Skeg-The extreme after part of the keel of a vessel; the portion that supports the rudder post. Skelp-A piece of plate prepared by forming and bending, ready for welding into a pipe. Flat plates, when used for butt-weld pipe, are called skelps. Slip joint-An inserted joint in which the end of one pipe is slipped into the flared or swaged end of an adjacent pipe. The two pipes are often soldered together. Slot weldr-A weld made in an elongated hole in one member of a lap or tee joint joining that member to the portion of the surfaces of the other member that is exposed through the hole. The hole can be open at one end and can be completely or partially filled with weld metal. (A fillet-welded slot should not be construed as conforming to this definition.) 445 ___j Slugging-Adding a separate piece or separate pieces of material in a joint before or during welding with a resulting welded joint that does not comply with design, drawing, or specification requirements. Sluice-An opening in the lower part of a bulkhead fitted with a sliding watertight gate or door having an operating rod extending to the upper deck or decks. These openings are useful in centerline bulkheads; in case of damage to one side of the vessel, the water can be quickly admitted to the other side before the vessel is dangerously listed. Snake-Wrapping a smaller line around a larger one, similar to worming. Snatch block-A block which can be opened on one side to receive the bight of a line. Snibs-Handles that can be operated from both sides of a watertight door. Soft patch-A temporary plate put over a break or hole and secured with tap bolts. It is made watertight with a gasket such as canvas saturated in red lead. Sole plate-A plate fitted to the top of a foundation to which the base of a machine is bolted; also a small plate fitted at the end of a stanchion. Sounding-Measuring the depth of water or other liquid. Spider bo,tten-Batten held in place by spider dogs. Spider dog-A device either of flat bar or wood, used to hold a batten on a curve line. Spiling-The curve of a plate or strake as it narrows to a point. Splice-A method of uniting the ends of two lines by first unlaying the strands, then interweaving them to form a continuous line. Spline-A flexible strip used for fairing lines. Spline plate-A vertical plate on the centerline, connecting to the nose plate above the stem casting. Splinter deck-The deck fitted with the lightest protective plating. SpTay coat-A spray coat consists of one or more passes, depending upon the paint and should be considered as that amount of paint applied at one time just short of sagging, running, wrinkling, and orange peeling. Squeeze time-In spot, seam, projection, and upset welding, the time interval between the initial application of the electrode force on the work and the first application of current. Stairway stringe1·-A channel or flanged plate used in making the sides of a set of stairs. StcLndaTd pipe-The standard adopted by the wrought pipe markers in 1886. The Briggs standard runs to 10-inch size inclusive and, by extending the pipe sizes, embraces the nominal sizes 11, 12, 13, 14 and 15 inches. For the 11-and 12-inch sizes, the outside diameters are 1 inch larger than the nominal diameter. By later agreement, the 9-inch size was changed from Brigg's size to a 9.625inch outside diameter. The thickness of all 10-inch sizes and under is determined by Brigg's rul.e; above 10 inches, it is 0.375 inch thick. Standard is also a term frequently but poorly used to inc!icate a regular or common product. Standing rigging-The heavy wire ropes which support spars or masts and which are permanently secured. Stay-A piece of rigging, either wire or hemp, used to support a mast. StiffeneT-An angle bar or stiffener used to stiffen plating of a bulkhead. Stopper-A short length of line secured at one ,end and used in securing or checking a running line. Stopwate1·-A plug of wood fitted transversely across the mating surfaces of a scarf joint. I.t is used to make a tight joint. Stmke-A term applied to a continuous row or range of plates. The strakes of shell plating are usually lettered, starting with A at the bottom row or garboard strake. a. Bilge strake-A term applied to a strake of outside plating running in the way of the bilge. b. Bottom strake-Any strake of plating AGO 5244A on the bottom of a vessel that lies between the garboard and bilge strakes. c. Clinker strake-An in-and-out lap stra:ke. d. Go·re strake-A strake which ends before reaching the stem or stern-post. Such strakes are laid at or near the middle of the vessel's sides to lessen the spiling of the plating. e. Landing strake-The second strake from the gunwale. f. Lim.ber strake-The strake on the inner skin of a vessel which is nearest the keel. g. Sheer strake-The top strake, just under the gunwale. Stress-relief treatm.ent-Vniform heating of a structure or portion thereof to a sufficient temperature below the critical range to relieve the major portion of the residual stresses, followed by uniform cooling. (Normalizing and annealing are misnomers for this application.) Stuffing box-Watertight gland used for making a watertight joint though bulkhead or deck; also called stuff tube. Surface preparation-The thorough cleaning of a surface to insure positive bonding of the applied paint to that surface. Surface t1·eatm.ent-The application of coating pretreatment to a cleaned and bare metal surface Ito provide intial corrosion protection and adhesive bonding of the primer coats to the metal surface. Surfacing-The deposition of filler metal on a metal surface to obtain desired properties or dimensions. Swash bulkheads-Longitudinal or transverse bulkheads fitted in a tank to decrease the swerving action of the liquid. Their function is greatest when the tanks are partially filed; without them, the unrestricted action of the liquid against the sides of the tank· would be severe. Swash plates-Pla.tes fixed in tanks to prevent excessive movement of the contained liquid. Sweat joint-A joint made by a flame instead of soldering iron. AGO 6244A Tack weld-A weld made to hold parts of a weldment in proper alinement until the final welds are made. Tem.plate-Pattern made from wooden strips, cardboard, or heavy paper. Teredo-A worm which eats into the unprotected hulls of wooden vessels. Th-ixotropic-Having the ability or phenomenon of becoming fluid when shaken. Thixotropic agents are light fillers which thicken plastics without causing runoff. Tholes-Pin in the gunwale of a vessel which is used in place of oarlock. Tie plate-A single fore-and-aft or diagonal coarse of plating attached to deck beams under wood deck to give extra strength T·ille·r-A short piece of iron or wood fitted into the head of the rudder by which is is turned. Toggle pin-A pin having a shoulder and an eye on one end called the head and the other end called the point which has its extremity hinged in an unbalanced manner so that it forms a T-shaped looking device to hold the pin in place. Tongue-The raised, middle section of a sternpost or propeller post which is fastened to the vertical keel. Tonnage, gross-The entire internal cubic capacity of a vessel expressed in tons, taken at 100 cubic feet each. The peculiarities of design and construction of the various types of vessels and their parts necessitate certain explanatory rulings in connection with this term. Tonnage, net-The internal cubic capacity of a vessel which remains after the capacities of certain specified spaces have been deducted from the gross tonnage. Topping lift-A line or chain extending from the head of a boom or gaff to a mast or to the vessel's structure, for the purpose of supporting the weight of the boom or gaff and its loads and permitting them to be rotated at a certain level. Tmnsom.-In steel ships, the framework of the stern at the sternpost; the upper part of the stern above the counter in a square sterned vessel. Transverse-Placed at right angles to the keel, such as a transverse frame and a transverse bulkhead. Two-blocked-The condition when the two blocks of a tackle have been drawn together as closely as possible by hauling on a fall. Ultra-speed _welding-(See Commutator-controlled welding.) Unbalanced rudder-A rudder whose area does not extend forward of the axis of rotation. Upset--A localized increase in volume in the region of a weld, resulting from the application of pressure. · Van stone flange-This flange slips over the pipe, and the ends of the pipe are heated and upset in a special machine to form the faces for the joint. The flanges are then pulled together with the joint between the faces. These joints are also used for high pressure work. Vee-out--To prepare for butt welding by making a vee-shaped joint. Vo'id-An empty space inside the armor belt for protection and for control of list and trim. Water ballast-Sea water used for ballast, let into the double-bottom, water-ballast or trimming tanks. Waterline-A term used to describe a line drawn parallel to the molded base line and at a certain height above it, as the 10-foot waterline. It represents a plane parallel to the surface of the water when the vessel is floating on an even keel, without trim. In the body plan and sheer plan, it is a straight line, but in the plan view of the lines it shows the contour of the hull line at the given distance above the base line. Waterline is also used to describe the line of intersection of the surface of the water with the hull of the vessel at any draft and any condition of trim. W eather deck-The portions of the main, forcastle, poop, and upper decks which are exposed to the elements. W eb frame-A frame built up transversely with a reinforcing web of wood or metal to give greater stiffness. Weeping-The passing of water through tiny pin holes in fiberglass laminates. Weldability-The capacity of a metal to be welded under the fabrication conditions imposed into a specific, suitably designed structure and to perform satisfactorily in the intended service. W elding technique-The details of a manualmachine, or semiautomatic-welding operation which, within the limitations of the prescribed joint welding procedure, are controlled by the welder or welding operator. Well-The space between the first bulkhead of a long poop deck or deckhouse and a forecastle bulkhead. Yok e-The piece .fitting across the head of a small craft rudder, to the ends of which the steering lines are attached; in a rising stem valve, the position of a bonnet that supports the nut, and handwheel; a pipe with two branches, as for hot and cold water, uniting them to form a single stream. Zinc protectors-High purity zinc anodes attached to metal surfaces to provide corrosion protection in a water environment by galvanic action. AGO 5244A INDEX Aluminum hulls, repair: Inspection --------------------Preservation and finishing ______ Repair procedures -------------Rivets and bolts -------------- Use of template and patterns ___ Welding ----------------------Anchor cable (chain) : Components and accessories ____ Maintenance and repair ________ Types ------------------------Anchors : Types ------------------------Uses -------------------------Anchor windlasses: Components ------------------Maintenance -----------------Types and classes -------------- Bedding compounds, application on wood hulls Boat davits: Maintenance Safety devices --------------- Safety precautions ------------ Testing ----------------------- Types ------------------------Bridgehouse and bridge ----------Bulkheads Cabin trunks Calking, wood hulls: Principles and procedures Tools ----------------------- Ceilings ------------------------- Ceramic tile Cleaning after haulout ------------ Coaming ------------------------ Compartments --------------------Corrosion Cranes --------------------------Damage control: Corrective measures ___________ Drydocking procedure Effects of damage -------------Flooding and sinking __________ Knowledge required -----------Material preparations __________ Objectives ------------------Piping repairs ---------------Prevention of progressive flooding and burning ---------------Procedures after compression failures -------------------Procedures after reaching anchorage ------------------ AGO 6244A Paragraph 182 188 184 187 185 186 257 258 256 255 254 261 262 260 152 252 251 250 253 249 51 37 150 149 49 65 116 49 42 58 56 98 111 96 102 93 104 94 109 106 100 101 Page 201 205 201 205 203 203 275 277 274 274 273 281 281 278 172 271 270 270 271 268 54 39 171 171 54 66 128 54 44 56 55 87 124 85 88 85 90 85 112 92 88 88 Protective equipment __________ Recovering sunken vessels ______ Restoring watertight integrity __ Shoring ---------------------- Stability training or repair parties -------------------- Scope -----------------------Strandings Types of damage ------------- Underwater damage ___________ Decay ----------------------------Deck beams ---------------------- Deck coverings : Canvas deck covering ---------Ceramic tile -----------------Concrete and aluminum diamond plating --------------------Magnesite -------------------Polyester resin and celastic coverings Surface preparation ___________ Resilient roll and tile __________ Rubber mastic ---------------Rubber matting Rubber sheet Rubber terrazzo Slip-resistant cloth ----------- Slip-resistant deck covering _____ Underlay -------------------Waterway gratings -----------Wood deckings Wood gratings ----------------Deck fittings: Mooring and gear fittings ______ Railings Through-deck fittings Deck fittings and hardware _________ Deck houses Decks Drydocking procedure ------------Dry Rot ------------------------ Electrolysis Engine beds ---------------------- Engine foundation, repair: Auxiliaries Cleaning, engine mounting Component replacement _______ Engine bedplate Engine bed shims ___________ _ Mounting rails Fastenings, wood hull ------------Filters, piping: Maintenance ------------------ Paragraph Page 99 87 110 120 107 94 108 107 103 90 92 83 105 90 95 85 97 86 61 60 36 34 80 78 65 66 66 68 67 68 68 69 64 66 69 72 70 73 71 76 72 77 73 77 74 77 75 78 76 78 77 78 78 78 79 78 264 284 265 287 266 289 48 54 53 55 47 49 111 124 59 59 62 61 41 44 230,231 254, 255 227 253 228 253 224 250 226 253 225 251 129 143 313 333 449 I_ -- Paragraph Page Paragraph Page Flooding -------------------------Floors ---------------------------Frames -------------------------- Haulout procedures: Beaching and tide ------------Floating drydock -------------Lift handling ----------------- Marine railway handling _____ _ Hatches, watertightness ----------Hull components: Bulkheads ------------------- Ceilings and coaming Deck fittings and hardware ____ Decks ----------------------- Engine beds ----------------- Floors Frames and deck beams Keels ------------------------ Keelsons Ladders --------------------- Lockers Partitions and compartments __ Planking and plating --------- Seatings --------------------- Seats and ladders Stringers -------------------- Walking fiats Hull fittings: Sea chests and valves Through-hull fittings __________ Hull repair: Hull repair categories Maintenance categories ________ Safety precautions Typical repair specification _____ Hull repairman requirements _______ Hull types: Flat bottom Round bottom ----------------V-bottom Inspection after haulout Joinery, wood hulls Keels -----------------------------Keelsons -------------------------- Ladders -------------------------Lockers Maintenance categories -----------Marking and insignia location layout, painting: Boat designator and serial number location -------------Bow and transom design _______ Service designation and boat designator for ring buoys and noninfiatable rafts ---------- Type of vessel --------------Masts ----------------------------Mildew -------------------------- 102 39 36 115 113 114 112 236 37 49 48 47 41 39 36 33 34 46 43 42 38 44 45 35 40 268 269 2 3 5 323 4 26 28 27 117 132 33 34 45,46 43 3 320 3Hl a21 a18 55 60 88 Outfit lockers 54 55 41 Painting: 34 Boat designator and serial number location -------------320 339 128 Bow and transom designation ___ 319 339 128 Exterior ---------------------315 335 128 Interior ---------------------316 336 128 Marking and insignia location 260 317 339 layout ---------------------Partitions -----------------------42 44 39 109 112 Piping repairs ------------------- 54 Piping systems: 54 Bolting joints in piping systems_ 282 301 49 Causes of inroficient operation 44 of traps 307 329 41 Cleaning strainers 310 330 34 Constant-support pipe hangers __ 290 31029 Cutting -----------------------276 298 32 Drain collection systems _______ 274 297 47 Filter maintenance ------------313 333 44 Flange face surface finish __ __ _ 280 300 44 Flange joints 278 299 41 Flareless fittings 285 306 44 Measuring piping 295 310 45 Miscellaneous connections 287 30734 Mountings -------------279 300 44 Permanent repairs 299 314 Piping definitions 271 297 290 Positive test for traps _______ _ 308 330 292 Renewing piping 300 315 Repair to gasketed joints _______ 281 301 3 Reseating valves -------------303 324 3 Semipermanent repairs 298 314 5 Separator maintenance 312 333 340 Sizing ------------------------277 298 4 Shock-resistant root nipples ____ 286 307 Sound and thermal insulation 293 310 21 Steam supply systems 27::! 297 23 Steam traps 305 327 23 Strainer locations 311 332 Support of branch connections __ 292 310 129 291 310 Sway braces ----------------- 149 Temporary or emergency repairs 297 314 29 Testing repaired piping _______ 301 315 32 Types of steam traps 306 328 45,47 284 305 lJnions ---------------------- 44 Valves ----------------------302 315 3 Valve repair -----------------304 325 Variable-spring pipe hangers ___ 289 309 Planking: Hull components, general ______ 38 41 339 Repairs -----------------------134, 136, 156, 161, 339 142 168 Replacing --------------------135 159 Plastic hulls, repair: 339 Repair kits ------------------171 196 339 Repair procedures -----------173 196 55 Safety precautions ------------172 196 59 Tools and materials, repair ___ 170 195 AGO 5244A Paragraph Page Paragraph Page 38 41 237 261 208 230 214,215 238,241 Plating Portlights, watertightness Propellers : Balancing Bearings Cavitation and noise Cleaning ------------------- Electrolysis, control Installation Maintenance of bearings Measuring after repairs Removal Repairs by welding Safety precautions, repair Shaft couplings Shafting Shafting and bearing alinement_ Shaft journals Straightening bent blades _____ Vibration Railings -------------------------Recovering sunken vessels __________ Repair of piping Rigging, standing: Adjustment Charring prevention Grounding and insulation Grounding masts -------------Inspection Insulator installation Seizing, splice ----------------Worming, parceling, and serving Rubber mastic --------------------Rubber matting Rudders -------------------------- Safety precautions, general Salvage equipment Salvage procedures: Clearing fouled propellers _____ Clearing or removing valves ___ Conditions affecting salvage operations -----------------Crew and duties Hazards and safety precautions__ Materials for emergency hull repair Materials required Recovering an anchor Salvage equipment Scribing, wood hulls Seatings Seats Separators, piping: Maintenance ------------------Shafting, propeller Shafts, propeller Shoring Sinking Skylights, watertightness Spi!ing, wood hulls Splicing, wood hulls Steam traps, piping: Causes of inefficient operation__ Positive test ----------------Types ------------------------ Steel hulls, repair: Application of paint Causes for repair ------------Inspection Preparation of paint _________ _ Repair materials Repair procedures Repair tools Surface preparation Types of repair Steering gears: Chain-cable Electro-hydraulic -------------Electro-mechanical Link rod Steam Steering gear components: Distant control system Emergency tiller Hydraulic systems Rudders Storage: Dry Prevention of electrolytic corrosion Wet Strainers, piping: Cleaning Locations --------------------Strandings Strength requirements: Maintaining material strengths__ Materials commonly used ______ Metals Stringers Superstructures: Bridgehouse and bridge ____ _ _ Cabin trunks Cranes _L _ _ ______ __ _ _________ _ Deck houses ------------------ Masts Outfit lockers ---------------Ventilation 168,169 190,195 161 178 159 177 168,169 190,195 201 202 217 206 216 207 203 205 209 211 210 213 212 204 200 265 110 296 241 246 247 245 240 243 244 242 70 198 5 82 88 89 86 85 84 87 83 90 82 133 44 45 312 223 224 248 229 242 230 224 227 230 234 231 236 235 225 223 287 120 312 265 268 268 267 265 265 267 265 73 220 5 81 82 83 82 82 82 82 81 83 81 154 44 45 333 210 210 108 102 238 133 132 307 308 306 163 165 164 167 160 191 194 193 190 192 196 195 197 198 120 121 119 310 311 105 32 30 31 35 51 52 56 53 55 54 57 231 231 107 88 263 154 149 329 330 328 179 183 182 190 177 209 213 211 207 211 217 217 218 220 135 138 130 330 332 90 27 24 25 34 54 54 55 55 55 55 55 AGO 52HA Tables: Areas and circumferences of circles from %2 to 10 inches in diameter --------------- Bearing troubleshooting chart Bolting material stretch -------· Centrifugal pump shaft bearing clearances (white metal) _____ Common angles and beams_____ _ Common material specifications_. Common woods -------------- Corrosion test of cadmiumplated naval brass attachments on aluminum alloy and clad aluminum__________________ Corrosion ·test of naval brass attachments on aluminum and clad aluminum___________ Cubic feet in a given number of U.S. gallons ------------Decimal equivalents of fractions. Decking applications, locations, and approved materials_______ Deductions for use with offset chart_____________ __________ Docking plan identification ____ __ Drill sizes -------------------- English and metric equivalents _ Fabricated steel bitt capacities__ Ferrous metals ---------------· Galvanic series in sea water ____ Line shafting spring bearing clearances -----------------Mariner's avoirdupois weight____ Mariner's circular or angular measure ------------~------ Mariner's measure Mariner's shipping measure ____ Mariner's volume -------------Melting points or temperature of fusion ------------------- Nonferrous metals__________ ___ Oil clearances for turbine, I reduction gear, generator, and motor bearings__________ Painting instructions __________ Recommended clearances for rudder bearings ------------- Recommended hole sizes for cold-driven aluminum alloy rivets with corresponding shear and bearing areas______ Recommended hole sizes for hotdriven aluminum alloy rivets Paragraph XXX XIII XXI XVI X XLV I VI v LV LVII VII XXIII XLVI XLIII XLVII XX II IV XVII LI LII XLVIII XLIX L XXXIII III XVIII XXVII XIV XXXVI Page 372 242 303 247 180 396 24 58 58 430 432 64 312 424 394 425 286 26 57 248 427 427 427 427 427 379 26 248 335 245 385 Paragraph Page with corresponding shear and bearing areas________ _______ XXXV 383 Recommended hole sizes for type A cadmium plated self tapping screws (in asbestos compositions) --------------- XL 389 Recommended hole sizes for type A cadmium plated self tapping screws (in plywood, resin impregnated) __________ XXXIX 388 Recommended hole sizes for type B cadmium plated self tapping screws (in castings, nonferrous) ------------- XLI 389 Recommended hole sizes for type B cadmium plated self tapping screws (in plastics) __ XXXVII 387 Recomm!!nded hole sizes for type B cadmium plated self tapping screws (in sheet metal) XLII 390 Recommended hole sizes for types A and B stainless steel self-tapping screws (in ply wood, resin impregnated) ____ XXXVIII 388 Recommended mooring gear by size -------------------- VIII 131 Recommended sizes of mooringlines _______ ______________ __ IX 132 Sag of No. 6 music wire________ XII 237 Steel repair hand tools ____ ____ XI 182 Stern tube and strut water lubricated bearing clearances_. XV 247 Temperature conversions ------· LVI 431 Tests for davits --------------- XIX 272 Threads, tap drills, and gages___ XXIX 369 Torque values ---------------- XXII 303 Troubleshooting chart for operation of traps -------- XXVI 329 Troubleshooting chart for pipe thread cutters ------------- XXIV 313 Troubleshooting chart for valve repair ---------·----------- XXV 325 Twist drill sizes ------------- XLIV 395 Typical tensil and bearing properties of aluminum alloy plates and shapes ____________ XXXIV 380 Typical types of nails ---------· XXVIII 367 U.S. gallons in a given number of cubic feet -------------- LIV 429 U.S. standard gage for sheet and plate iron and steeL______ XXXI 375 Weights of materials __________ LIII 428 Weights of sheets and plates of steel, copper, and brass ______ XXXII 377 AOO 6244A 4U Template making, wood hulls Tiller, emergency ----------------- Valves, pipings: Reseating -------------------Repair ----------------------- Vessel types: Amphibians ------------------Floating craft ---------------Landing craft ----------------Miscellaneous vessels ---------- Walking flats --------------------Watertight integrity: Bulkhead openings ----------Hatches ---------------------Maintaining -----------------Portlights -------------------Restoring -------------------Skylights -------------------- Standards --------------------Wood hulls, repair Application of paint ___________ Batten, patching -------------- Paragraph 133 195 303 304 9 7 8 10 40 235 236 234 237 107 238 233 Page 154 217 324 325 10 7 10 10 44 258 260 257 261 94 263 257 156,157 174,175 146 170 Paragraph Page Bulkhead repair --------------147 170 Causes for repair -------------125 140 Chine guard repair -----------139 165 Coaming repair ---------------140 166 Decayed wood --------~--------138 164 Fastenings -------------------129 143 Frame repair -----------------144, 145 169,170 Garboard strake repairs _______ 137 164 Guard or rub strake repair____ 141 167 Inspection --------------------126 140 Laminated bending ------------131 148 Materials for repair -----------127 141 Methods of construction _______ 123 139 Planking repairs ______________134, 136, 156, 161, 142 168 Plywood repair ---------------143 169 Preparation of paints ________ 155,157 173, 175 Preparation of surface --------154 173 Scribing, spiling, and template 133 154 making --------------------Splicing and joinery ---------132 149 Steam bending --------------- 130 148 Tools for repair ---------------128 142 AGO 62HA 453 j By Order of the Secretary of the Army: Official: J. C. LAMBERT, Major General, United States Army, The Adjutant General. Distribution: Active Army: DCSOPS (2) DCSPER (2) CAR (1) CRD (1) ACSI (2) ACSRC (2) ACSFOR (2) CA (2) CINFO (2) TIG (1) TJAG (1) CNGB {2) CORC (2) CMH (1) TPMG (2) CofEngrs (2) TSG (2) USAMC (5) CC-E (2) Dir of Trans (2) DCSLOG (3) CofSptS (2) USACDCTA (2) USCONARC (10) LOGCOMD (5) USAMOCOM (5) USAMEC (5) OS Maj Comd (10) NG: None. USAR: None. For explanation of abbreviations used, see AR 320-50. HAROLD K. JOHNSON, General, United States Army, Chief of Staff. Armies (10) USMA (5) Svc Colleges (2) Br Svc Sch (10) USACDCEA (2) USACDC (5) USAMB (2) USATEA (1) USA Tml Comd (5) Units org under fol TOE: 55-111 (2) 55-116 (5) 55-117 (1) 55-118 (1) 55-121 (2) 55-128 (5) 55-129 (5) 55-131 (2) 55-138 (5) 55-139 (5) 55-140 (5) 55-157 (10) 55-158 (5) 55-500 FG, FI, FJ, FK, FL, FN, FP, FQ, IA (1) IB, IC, ID (5) IE (10) 55-510 (10) i:l U.S. Government Printing Office: 1966-250-573/ 5244A AGO 6244A