f V M /9/(^_ UC-NRLF B 3 lis ni m- -J A Circular for the information of ^ersons Desiring to Enter the Navy as Acting Ensigns for Engineering Duty illlMtlt»iU!i!i:ii im Digitized by tine Internet Arciiive in 2008 witii funding from IVIicrosoft Corporation Circular for the information of Persons Desiring to Enter the Navy as Acting Ensigns for Engineering Duty WASHINGTON GOVERNMENT PRINTING OFFICE 1916 Kv.'^ h M CmCULAE FOR THE INFORMATION OF PERSONS DESIRING TO ENTER THE NAVY AS ACTING ENSIGNS FOR ENGINEERING DUTY. An act of Congress approved August 29, 1916, authorizes the appointment of 30 acting ensigns, annually, as follows: ' ' That the Secretary of the Navj^ is hereby authorized to appoint annually in the line of the Navy for a period of ten years following the passage of this act, in the order of merit determined by such competitive examination as he may prescribe, thirty acting ensigns for the performance of engineering duties only. Persons so appointed must have received a degree of mechanical or electrical engineer from a college or university of high standing or be graduates of technical schools approved by the Sec- retary of the Navy, must have been found physically qualified by a board of medical officers of the Navy for the performance of the duties required, and must at the time of appointment be not less than twenty nor more than twenty -six years of age. Such appointments shall be for a probationary period of three years, and may be revoked at any time by the Secretary of the Navy. "Such acting ensigns shall, upon the completion of the probationary period of three years, of which two years shall have been spent on board cruising vessels and one year pursuing a course of instruction at the Naval Academy prescribed by the Secretary of the Navy, be commissioned in the grade of lieutenant of the junior grade after sat- isfactorily passing such examination as may be prescribed by the Secretary of the Navy, and having been recommended for promotion by the examining board and found physically qualified by a board of medical officers of the Navy. "Such officers shall thereafter be required to perform engineering duties only, and shall be eligible for advancement to the higher grades in the manner herein pro"\dded for line officers assigned to engineering duty only." APPOINTMENT. A candidate for appointment as acting ensign for engineering duty must, at the time of appointment, be a citizen of the United States, not less than 20 nor more than 26 years of age, a candidate who has passed his twenty-sixth birthday not being eligible. Attention is particularly invited to the italicized portion of the preceding sentence. Although a candidate may successfully pass the professional and physical examination his appointment can not be made unless he i.s within the prescribed age limit at the time he accepts an appointment that may be tendered by the depart- ment after passing all examinations. The age limit is prescribed l)y law and the Navy Department has no discretion in the matter of wai^ving same. Therefore, no person will be permitted to appear who will pass his twenty-sixth birthday within two months after the date set for the examination. This is done in order to prevent candidates from going to the trouble and expense of appearing for examination when it is certain that they can not be examined, ha^•e their papers marked by the local board in Washington, and their appointments issued and accepted before reaching the statutory age limit of 26. 86721—16 (3) 345»27 Applir.£.tiT)iifr l'(^r appoint avent ehould be made to the Thief of Bureau of Navigation, Navy Department, Washington, D. C, and one requirement is that the application i>e in the handuriting of the candidate, and in the following form: 191. Sir: I request permission to be examined at , for appointment as acting ensign for engineering duty. I was bom at on day of ; and am a citizen of the United States, residing in County of , in the State of My occupation is that of , am a graduate of ; character of degree received The following is a description of my scientific work performed before or after graduation , I am inclosing certificates as to moral character, habits, and citizensliip; also a certificate from the faculty of the above-mentioned school (or college) which shows the full course pursued, my relative standing, the degree conferred on me, and my deportment as a student. Very respectfully, The Chief of Bureau op Navigation, Navy Department, Washington, D. C. Applications must be accompanied by testimonials as to citizenship, good moral character, and correct habits, from at least two persons of prominence who have personally known the applicant long enough to form a correct opinion of hipi. Upon the receipt of an application for appointment as acting ensign same will be promptly acknowledged, and if the candidate is considered eligible a permit will be issued in time to enable him to appear for the professional examination. PROFESSIONAL EXAMINATION. The professional examination of candidates will be held simultaneously tloroughout the United States, after which all papers will be forwarded to the local board at Wash- , ington, D. C, for marking. When this has been done permits will be issued to the successful candidates authorizing them to appear for the physical examination. Candidates should promptly advise the Bureau of Navigation of any change of address in order that permits, if issued, may reach them promptly-. The following sample schedule of subjects and sample set of questions are given in order that candidates may have an idea of the scope of the professional examination: Day. Time. First Hours. 3 Second... 3 3 3 Third.... J'ourtn... 3 1? H 2i Subjects. Marine engineering. — Propelling machinery. (Sheet A.) Marine engineering — Boilers. (Sheet B) Marine engineering — Auxiliary machinery and operations. (Sheet C.) Marine engineering— Internal combustion and explosive engines. (Sheet D.) Elecl ricity. (Sheet E) Applied mechanics. (Sheet F) Heat and thormo-dynamics. (Sheet G) Hydraulics and pneumatics. (Sheet H) Physics and chemistry. (Sheet I) Shop methods, and hand and machine tools. (Sheet J.) From- 9 a. m. to 12 m. 2p. m. to 5p. m. 9 a. m. to 12 m . . . 2p. m. to5p. m. 9 a. m. to 12 m 1.15 p. m. to 3 p. m 3.15 p. m. to 5 p. m 8.30 a. m. to 10.15 a. m.. 10.30 a. m. to 12.15 p. m. 2 p. m. to 4.30 p. m Aver- age. MARINE ENGINEERING — -PROPELLING MACHINERY. (Sheet A.) M. E. 1. Describe a modern triple expansion marine engine and tlie auxiliary ma- chinery necessary for its operation. M. E. 2. Sketch and describe the Stephenson link valve gear as used on marine engines. In a multiple expansion marine engine, how is this valve gear fitted so as to permit the independent varying of the cut-off in each cylinder when going ahead, the steam to follow full stroke when backing? M. E. 3. Describe the method of measuring the pitch of a screw propeller. Illustrate ^\ith sketches. Explain the meaning of the following terms: (a) Helicoidal area, (b) Projected area, (c) Disk area, (d) Pitch. (e) Slip. M. E. 4. Describe the Parsons marine steam turbine. Show by diagi'am the action of the steam on the blades and sketch and describe the following details: dummy cylinders, casing and packing rings; facial, and fin or radial pack- ing rings, stating where and why each type of packing ring is used, and clearance in each case. M. E. 5. Explain the principles of the steam engine indicator. Applied to the cylinder of a marine engine, what points are revealed directly by the diagram? What particulars may be calculated or inferred? How many indicators are used for each cyhnder, and how are they connected? MARINE ENGINEERING — BOILERS. (Sheet B.) B. 1. Name, sketch, and describe a water-tube marine boiler used on a seagoing vessel, showing clearly its main features. Show by arrows the circulation of . the water and of the gases of combustion. Give two views of the boiler. State the material used in the following parts: Steam drums, headers or down comers, and tubes. B. 2. Give descriptions and explanations of what is meant by the terms "Closed fire- room system of forced draft" and "Closed ashpit system of forced draft," with the comparative advantages and disadvantages of the two systems. How is the intensity of the draft measured? B. 3. Give a full description of an oil-burning system, including the fuel storage and settling tanks, piping, and burners. B. 4. Describe a gas-analysis apparatus and its use as applied to .smokestacks. What are the benefits gained from its successful operation? B. 5. What is the object of a time-firing device in the engine and fire rooms of a sea- going vessel? Give a detailed description of one type and its method of operation. MARINE ENGINEERING — AUXILIARY MACHINERY AND OPER.\TION. (Sheet C.) A. M. & O. 1 . Describe an evaporating and distilling plant as fitted on board a modern seagoing vessel to supply fresh water, showing by outline sketch all its component parts, connections, lead of piping, and attachments. A. M. & O. 2. State the principles involved in refrigerating by the comi^ression and expansion of a gas, and describe in detail, including all fittings, the refrigerating apparatus as used on board a seagoing vessel. Only outline sketches required. A. M. & 0. 3. Describe a hydraulic ash ejector, discharging above the water line, and explain its operation. How is excessive erosion at the curves in the discharge pipe prevented? What type of pump is necessary for its operation? State reasons. A. M. & O. 4. How do you measure the clearance between a journal and its brasses? What clearance would you permit for crank-pin journal of a large marine engine? A. M. & 0. 5. Describe in detail and in proper sequence the routine of operation and management, in a fireroom and in an engine room, in raising steam and starting a reciprocating engine. A. M. & 0. 6. Describe the process of warming up a turbine preparatory to starting it. State type of turbine. - ■ A. M. & 0. 7. With coal as fuel, what percentage of COj in the smoke-pipe gases represents maximum efficiency? How is the percentage of COj determined? Wliat effect has a leaky boiler casing on the percentage of COj? INTERNAL COMBUSTION AND EXPLOSIVE ENGINES. (Sheet D.) I. C. E. 1. Describe the basic principle employed in the operation of a gasoline or explosive engine and the Diesel or internal combustion engine, stating clearly the difference between the two. No sketches required. I. G. E. 2. Describe the 2-cycleand 4-cycIe types of gasoline engines and their opera- tion, illustrating your answer with sketches as necessary. I. C. E. 3. Describe the 2-cycle and 4-cycle types of Diesel oil engine and their opera- tion. Illustrate your answer with sketches as necessary. How does the economy of this engine compare with that of the steam engine? I. 0. E. 4. Sketch a carbureter and describe its operation as used with a gasoline engine; the sketch to show a cross section. I. C. E. 5. Discuss the use of Diesel engines of the 2 and 4 cycle types for the propulsion of seagoing vessels in competition with the steam engine. State which type you consider the best, giving reasons for your selection. ELECTRICITY. (Sheet E.) E. 1. Name and define the international or legal electrical units. E. 2. Define alternating current, frequency, cycle, and electric oscillation. For what purpose is alternating current used on board naval vessels, and how is it generated? E. 3. Describe a motor generator and a dynamotor and their operation. E. 4. No. 1 dynamo is in operation and delivering current to the bus bar. On account of increased load, it is necessary to start No. 2 dynamo and connect it in parallel with No. 1. Explain what is meant by connecting the two dynamos in parallel, and how it is accomplished. Make line sketch showing leads, switches, etc. E. 5. State the fundamental principle of wireless telegraphy. Describe a radio plant and its operation. Make outline sketch showing all parts. APPLIED MECHANICS. (Sheet F.) 1. (a) Specify some of the different stresses propeller shafts are subject to in sea- going vessels. (6) Wliat is the equivalent of 1 horsepower in foot-pounds per second? 2. (a) What is the difference between "moment of a force" and "momentum of a body"? (6) What is meant by "dead load" friction and friction of the "working load" in a marine engine? 3. To what pressure are Scotch boilers tested and what methods are commonly used? 4. Specify what kind of material is used for the following parts of engines or turbines: (a) Steam cylinders. (6) Piston rods, (c) Bedplates, (d) Headers in Babcock & Wilcox boiler, (e) Turbine rotors. (/) Turbine casings, (g) Condensers and condenser tubes. 5. Explain the assumptions made in connection with the subject of boiler bracing, and show how the principles of mechanics are applied in these problems. HEAT AND THERMODYNAMICS, (Sheet G.) a) What is meant by a British thermal heat unit (B. t. u.), and how many, approximately, are there in a pound of coal and oil, respectively? b) What means are used for measuring furnace and uptake temperatures in boiler installations? a) What is moisture in steam?. Describe how it is measured. b) What is superheated steam and how is it obtained? What is the Umit of superheat used in marine engines, and why? a) What is thermodynamic efficiency? b) Give an idea about the method used for an approximate determination of the thermod^-namics efficiency of an engine or tiu:bine. a) State what is meant by total heat in saturated steam and what parts it con- sists of. 6) Enumerate and explain the principal heat losses in a steam plant; in the boilers; in the engine. a) What is the effect of the variation of the load on the efficiency and steam consumption of a steam engine and what are the principal causes? What is: 6) Efficiency of the boiler? c) Efficiency of the boiler and grate? HYDRAULICS AND PNEUMATICS. (Sheet H.) a) Explain what is meant by a contracted weir, a suppressed weir, and triangular weir. Which is the most accurate for measuring, a triangular or a rectangular weir? b) In the flow of water from a tank through a sharp-edged orifice what coefficients have to be considered in finding the quantity of water flowing through this orifice? a) A pump is used to force feed water into a boiler. Explain the different heads that have to be taken into account in pumping the water. b) How would you find the horsepower necessary to pump water to a certain height? 3. (a) Explain and describe a Piezometer tube, a pitot tube, and a Venturi meter. 6) How would you find the total pressure on the bottom of a tank completely full of water? 8 1. («) (b) (c) (d) 2. (a) (b) 3. (a) (b) 4. (a) (b) 5. (a) (b) (c) 4. How is slip of a pump figured? Duty trials of a pump? What are the efficiencies of centrifugal and reciprocating pumps? 5. (a) What type of air compressor would be necessary to compress air from atmos- pheric pressure to 1,000 pounds per square inch? (b) Why is a multiple stage compressor more economical than a single stage for high degrees of compression? PHYSICS AND CHEMISTRY. (Sheet I.) What instruments are used for measuring vacuimi, engine, and boiler pressure? What is compound gage and where is it used? What is "pressure of gage"? What is absolute pressure? Describe the process of the formation of boiler- tube incrustation. What is the remedy? Explain the causes of corrosion in boilers, condensers, sea connections, pro- pellers, and shafting. What partial remedy exists? Explain combustion of fuel. Which are the principal fuels? What average percentage of phosphorus and sulphur may be allowed in first- class machinery forgings? ^Miat physical effect upon the general properties of the material may be ascribed to the presence of such ingredients? What is Dalton's law as to gas mixtures? KNOWLEDGE OP SHOP MACHINERY, GENERAL SHOP PRACTICE, AND REPAIR WORK. (Sheet J.) , Describe the molding, casting; and machining of a cylinder for a marine engine. The description to include all tools used and shops in which the work is done. The cylinder to be machined ready for installation. List of points authorized for professional examinations. Birmingham. Demopolis. Doth an. Florence. Himtsville. Mobile. c. n. Montgomery. (Jpelika. Clifton. Douglas. Flagstair. Globe. Phoeni.\. Prescott. Tucson. Yuma. Camden. Fayette ville. Fort Smith. Arkansas ■( Helena. Jonrsboro. Little Rock. Te.xarkana. Chico. Eureka. Fresno. Los Angeles. Red niull. California { Riverside. Sacramento. San Diego. San Francisco. San Jose. San Luis Obispo. Alabama. Arizona. ColoradoSprings. Albany. Denver. Athens. Durango. Atlanta. Fort Collins. Augusta. Fort Morgan. Georgia Columbus. Colorado Grand Junction. La Junta. Macon. Rome. Leadville. Savannah. Monte Vista. Thomasville. Montrose. Waycross. Pueblo. .Trinidad. Hawaii Honolulu, c. Hartford. Boise. Middletown. Coeur d'Alene Connecticut New Haven. New London. Grangeville. Moscow. Waterbury. Willim antic. Idaho.. Pocatello. Sandpoint. St. Anthony. Delaware Dover. Wilmington. Twin Falls. Weiser. District of Co- Cairo. lumbia Washington. Urbana. Chicago. Gainesville. East St. Louis Jacksonville. Effingham. Key West. Illinois Freeport. Florida Miami. Pensacola. Gale.sburg. Peoria. San ford. Quincy. Tallahassee. Rock Island. Tampa. Springfield. Lut of points authorized for projessional exananations ~ Qoniinued. Angola. Bloomington. Evcinsville. Fort Wayne. Indianapolis. Jeffersonville. La Fayette. Marion. Richmond. South Bend. Terra Haute. .Valparaiso. Ames. Burlington. Cedar Rapids. Coimcil Bluffs. Creston. Davenport. Denison. Des Moines. Dubuque. Fort Dodge. Iowa City. Mason City. Ottumwa. Sioux City. Spencer. .Waterloo. Concordia. Dodge City. Emporia. Fort Scott. Kansas City. Lawrence. Leavenworth. Manhattan. Norton. Pittsburg. Salina. Topeka. Wichita. Ashland. Bowling Green. Covington. Hopkinsville. Lexington. lyouisville. Middlesboro. Owensboro. Paducah. .Somerset. Alexandria. Baton Rouge. Lake Charles. Monroe. New Iberia. New Orleans. c.H. Shrev'eport. Bangor. Bath. Calais. Caribou. Houlton. Lewiston. Portland. .Rockland. I Baltimore. Cumberland. Easton. Salisbury. Boston. Brockton. Fall River. Fitchburg. Hyannis. Lawrence. Lowell. Pittsfield. Salem. Springfield. .Worcester. Michigan . Minnesota. Mississippi . Missouri . Massachusetts . Nebraska . Nevada. Ann Arbor. Chebovgan. Detroit. Escanaba. Grand Rapids. Ironwood. Kalamazoo. Lansing. Manistee. Marquette. Saginaw. Sault Ste. Marie. .Traverse City. Austin. Bemidji. Brainerd. Crookston. Duluth. Fergus Falls. International Falls. Mankato. Minneapolis. Pipestone. St. Cloud. St. Paul. Virginia. Willmar. .Winona. Corinth. Greenville. Grenada. Hattiesburg. Holly Springs. Jackson. Meridian. Natchez. Vicksburg. .West Point. Cape Girardeau. Columbia. Jefferson City. Kansas City. Kirksville. Moberly. Poplar Bluff. St. Joseph. St. Louis OLD CH. Springfield. IWarrensburg. Billings. Bozeman. Butte, (ilasgow. Great Falls. 1 Havre. Helena. Kalispell. Miles City. Missoula. Alliance. Beatrice. Broken Bow. Chadron. Columbus. Grand Island. Holdrege. Lincoln. McCook. Nebraska City. Norfolk. North Platte. Omaha. O'Neill. Carson City. Elko. Ely. (Joldfield. Reno. Fallon. New Hamp- shire, Berlin. Concord. Hanover. Keene. Manchester. Plymouth. Portsmouth. I Atlantic City. Camden. Newark. Trenton. New Mexico. ..• New York . North Carolina North Dakota. Ohio. Oklahoma . Albuquerque. East Las Vegas. Las Cruces. Raton. Roswell. Santa Fe. Tucumcari. Binghamton. Buffalo. Elmtra. Ithaca. Jamestown. New York. c.H. Ogdensburg. c.H. Plattsburg. Poughkeepsie. Roche,ster. Syracuse. Troy. .Utica. Asheville. Charlotte. Durham. Goldsboro. Greensboro. Hickory. Raleigh. Salisbury. Washington. Wilmington. Bismarck. Devils Lake. Dickinson. Fargo. Grand Forks. Minot. Valley City. 'Williston. Akron. Athens. Chillicothe. Cincinnati. Cleveland. Cohimbus. Dayton. I ronton. Lima. Mansfield. Marietta. Portsmouth. Sandusky. Stpubenville. Toledo. Youngstown. Zaneaville. Altus. .\rilmore. Enid. Guthrie. Lawt on. Me A lost er. Muskogee. oklalioma. Vinita. Woodward. ■"-^^^' H THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.00 ON THE SEVENTH DAY OVERDUE. f'^r :.. ' -"■■• f S]ii\' '^'- '■■ ■ LD 21-100m-7,'40 (6936s) ^m^M^mmmri^m