LIBRARY 
 
 I UNfVSKWTY Of 
 \CAUFOflNJA 
 
 This volume, prepared under the supervision of 
 
 ^ P 
 
 and published by the War Department, is the 
 property of the United States and by direc- 
 tion of the Secretary of War is deposited with 
 
 1-J**&&g^+^--SV;. 
 
 foi' official use. 
 
 Section 74 of the act of Congress approved 
 January 12, 1895, provides as follows: 
 
 "Government publications furnished to judicial and 
 executive officers of the United States for their official 
 use shall not become the property of these officers, but 
 on the expiration of their official term shall be by them 
 delivered to their successors in office, and all Govern- 
 ment publications delivered to designated depositories 
 or other libraries shall be for public use without 
 charge." 
 
 Form 87. 0. C. 8. 
 Ed. 10-13-1150,000. 
 
 31071 
 
MANUAL FOR 
 SUBMARINE MINING 
 
 EDITION OF 1912 
 
 R. W. FINGER. 
 
 2nd Lieut. Coast Artillery Corps 
 
 Registered Number 
 DEC 3 1912 
 
 WASHINGTON 
 GOVERNMENT PRINTING OFFICE 
 
 1912 
 

 
 WAR DEPARTMENT, 
 
 Document No. 399. 
 
 Office of the Chief of Staff. 
 
Y oo 
 
 WAR DEPARTMENT, 
 OFFICE OF THE CHIEF OF STAFF, 
 
 Washington, June 29, 1912. 
 
 This Manual for Submarine Mining, revised to 1912, is 
 approved and published for the confidential information and 
 guidance of the Army of the United States. Under no cir- 
 cumstances shall its contents be divulged to persons not in 
 the military or naval service of the United States. 
 By order of the Secretary of War: 
 
 WM. H. CARTER, 
 Major General, Acting Chief of Staff. 
 
 447 
 
OOl^TE^TS. 
 
 Page. 
 
 CHAPTER I. Definitions and general principles 7 
 
 II . Materiel of the system 11 
 
 III. Loading-room duties 34 
 
 IV. Locating distribution box, laying multiple cable, mark- 
 
 ing out mine field 42 
 
 V. Assembling and planting mines 48 
 
 VI. Test of mines and apparatus 56 
 
 VII. Taking up mines 62 
 
 VIII. The mine command 65 
 
 APPENDIXES. 
 
 1. Explosives. . . .'. 69 
 
 2. Oil engine and generator 77 
 
 3. Storage battery , 84 
 
 4. Submarine-mine cable 92 
 
 5. Care and preservation of materiel 106 
 
 6. Instructions for masters of mine planters 110 
 
 7. Manual for small boats 114 
 
 8. Supply list 120 
 
 5 
 
CHAPTER I. 
 DEFINITIONS AND GENERAL PRINCIPLES. 
 
 A submarine mine consists of an explosive charge inclosed 
 in a water-tight case, and a firing device, the whole intended 
 to be submerged in a waterway which it is desired to close 
 against the passage of an enemy's vessels. 
 
 With respect to the position of the case containing the ex- 
 plosive, submarine mines are of two classes, buoyant and 
 ground. 
 
 In the buoyant mine, the case contains the explosive and 
 the firing device, and has such excess of buoyancy that it 
 would float were it not held below the surface by a mooring 
 rope and an anchor. The submergence is such that, while 
 the mine w r ould be struck by the hull of a passing vessel, it is 
 not so near the surface as to be seen. 
 
 Buoyant mines may be planted and operated successfully 
 in water 150 feet deep. They should not, in general, be used 
 where the depth of water is less than 20 feet. 
 
 In the ground mine, the case contains the explosive and 
 the firing device, and is heavier than the displaced water; 
 it therefore rests upon the bottom and requires no anchor. 
 Ground mines are not used where the depth of water exceeds 
 35 feet. 
 
 With respect to the means used to fire them, mines may be 
 classed as mechanical and electrical. 
 
 Electrical mines are, in turn, of two general classes, con- 
 trollable in which the firing device is under control after 
 the mine has been fixed in position ; and noncontrollable in 
 which no such control is had. 
 
 Mechanical and noncontrollable electrical mines are in- 
 tended to be fired only by the blow of a passing vessel. 
 When once in position they are dangerous alike to friend 
 
 7 
 
8 SUBMARINE MINING. 
 
 and foe, while controllable mines may instantly be made safe 
 for friendly vessels or as quickly made dangerous to vessels 
 of the enemy. 
 
 Controllable electrical mines are arranged so as to give a 
 signal to the operator when they are struck. They may be 
 set to fire automatically wjien struck or tampered with, or 
 may be fired at the will of the operator. In the latter case 
 the firing may be delayed, in which case the operator fires 
 the mine some short interval after the signal indicates that 
 it has been struck; or by observation, in which case he fires 
 it after the position-finding system shows that the vessel has 
 come within the mine's destructive radius.. 
 
 LOCATION OF MINES. 
 
 The considerations involved in the location of mines are of 
 two general classes, tactical and local. 
 
 Tactical considerations deal with the position of mines 
 with reference to the other defenses. Local considerations 
 deal with the width and depth of the channel, the swiftness 
 of the current, the variation of the tide, and the relative im- 
 portance of the harbor. 
 
 Where ordinary ship channels are unobstructed it is pos- 
 sible for modern battleships, with their high speed and 
 heavy armor, to run by shore batteries, at least in the night 
 or during a fog; hence the defense of such channels should 
 not be left to guns alone. 
 
 On the other hand, where mines are unprotected by the 
 fire of shore batteries it is possible for an enemy to remove 
 or disable them. 
 
 Therefore guns and mines, the two elements of the fixed 
 defenses of a harbor, are mutually dependent, and when the 
 location of one has been decided upon that of the other must 
 conform thereto. 
 
 Within the. zone between 4,000 and 8,000 yards of the main 
 defense the fire of heavy guns is destructive for warships, 
 yet the latter are at such a distance that their rapid-fire guns 
 will be of little effect against the batteries. 
 
SUBMAKINE MINING. 9 
 
 Moreover, at 4,000 yards vessels are just beyond the inner 
 limit of mortar fire. 
 
 If possible, therefore, hostile vessels should be held in this 
 zone by some obstacle. Such obstacle is afforded by a mine 
 field. ' 
 
 On the other hand, attacks upon a mine field are most 
 liable to be made by small boats at night. If the mine field 
 be at too great a distance from the defenses, these boats will 
 not be revealed by the mine searchlights. Furthermore, for 
 protection against such attacks, the defense relies upon 
 rapid-fire guns of relatively limited range. 
 
 Due to the above considerations the outermost mines are 
 usually placed between 3.000 and 4,500 yards from the main 
 defense. 
 
 In general, there should be in each main channel at least 
 three lines of mines. 
 
 ELEMENTS OF A MINE SYSTEM. 
 
 The elements of a mine system are : 
 
 1. The mining casemate, consisting typically of four rooms : 
 ( 1 ) The operating room, containing the power panel and the 
 operating boards; (2) the engine room, containing the en- 
 gine and the generator; (3) the battery room, containing 
 the storage battery; and (4) the sleeping room for the 
 personnel. 
 
 2. The multiple cables, 7 and 19 conductor, leading from 
 the casemate out to the distribution boxes, one of which is 
 in the center and rear of each group of mines, 
 
 3. The single-conductor cables, radiating to the front from 
 the distribution boxes, one leading to each mine. 
 
 4. The mines, in groups of 19 or less, extending across the 
 waterway to be defended, planted approximately 100 feet 
 apart and anchored so as to have a submergence of about 10 
 feet at low water. The groups are numbered 1, 2, 3, etc., 
 from left to right of the observer stationed in rear of the 
 line, and the mines in each group are numbered similarly, 
 No. 1 being on the left, No. 10 in the center, and No. 19 on 
 the right. 
 
10 SUBMARINE MINING. 
 
 The groups composing a line of buoyant mines are not 
 usually planted in prolongation of each other, but with a 
 space for the passage of friendly vessels, and also for the 
 movement of the planter when at work upon adjacent 
 groups. Groups of ground mines may be placed in prolon- 
 gation of each other or between the groups of buoyant mines, 
 as they will always be below the hulls of passing vessels. 
 
 5. The mine planters and other boats with the necessary 
 equipment for planting and maintaining the planted mines. 
 
 6. The range-finding 1 system, the same as or similar to that 
 used for the guns, enabling accurate plotting of the positions 
 of the individual mines, and consequently permitting vessel 
 tracking and observation firing. 
 
 7. The searchlights, for illuminating the mine fields at 
 night. 
 
 8. The rapid-fire guns, for the protection of the mine fields. 
 
CHAPTER II. 
 MATERIEL OF THE SYSTEM. 
 
 The generating set. This consists of a D. C., shunt-wound 
 generator driven by a kerosene oil engine, or of a direct - 
 connected gasoline set. (For method of operation of a 
 Hornsby-Akroyd oil engine, see Appendix 2.) 
 
 The storage battery. This is a 40-cell chloride accumulator, 
 with a normal charge and discharge rate of 5 amperes. The 
 voltage may be taken at 2 volts per cell ; the internal resist- 
 ance is negligible. Directions for setting up, care, and 
 usage of the storage battery are given in Appendix 3. The 
 5-ampere battery is the standard equipment at the present 
 time, but the new installations will have batteries with a 
 normal charge and discharge rate of 15 amperes. 
 
 The motor-generator, D. C.-A. C. This is a D. C.-A. C. (60- 
 cycle, 'single phase) machine, running on D. C. voltage 
 (80-110) and designed to give one-half kilowatt at 80 volts. 
 To insure against breakdown two of these motor generators 
 are supplied to each casemate. 
 
 Starting switch. This is a 4-point lever switch and is used 
 to start the motor-generator and to accelerate it to full speed. 
 To insure against breakdown two of these motor-generators 
 cuit to the fourth -point. Resistances are connected between 
 the points, as shown in figure 1. The contact made at point 1 
 is not broken as the lever is moved to its successive positions. 
 It is seen that the total resistance is 8 ohms; it is all in the 
 armature circuit when the switch blade is in the first point; 
 4 ohms when in the second point; 2 ohms when in the third 
 point; none when in the fourth point. The operation of 
 closing the lever short circuits in turn the resistances 4, 2, 
 and 2. 
 
 11 
 
12 
 
 SUBMARINE MINING. 
 
 The casemate transformer. This is a step-up transformer, 
 of the oil-insulated core type, and is rated at 60 cycles, 500 
 watts, 80 volts primary and 500 volts secondary, when carry- 
 ing full load. 
 
 Line 
 
 FIG. 1. Starting switch. 
 
 The power panel. This panel is shown in figure 2, its wir- 
 ing diagram in figure 18 at the end of the book. It consists 
 of an enameled slate panel upon which the apparatus is 
 mounted. It is 32 inches wide, 69 inches high, and is set up 
 with its face 34 inches from the wall in rear. 
 
\ 
 
 FIG. 2. POWER PANEL. 
 
SUBMARINE MINING. 13 
 
 Across the top are two lamps, a double circuit breaker, a 
 D. P. D. T. switch, and a single circuit breaker. Below these 
 there are an ammeter, an A. C. voltmeter, and a D. C. volt- 
 meter. Below the ammeter is a battery rheostat and below 
 the D. C. voltmeter a field rheostat. On a bracket at the side 
 there is a mil-ammeter, with a 16 c. p., 110- volt lamp in series 
 with it. 
 
 The remaining switches, receptacles, and attachments are 
 sufficiently well indicated in the figures. 
 
 Switch No. 1 controls the lamps at the top of the board. 
 When it is up, they are supplied from an external source of 
 power. When it is down, they are supplied from the stor- 
 age battery. 
 
 The D. C. terminals are all carried to one terminal bar, 
 the A. C. terminals to another. All terminals and all switches 
 are labeled. 
 
 Provision is made for energizing the D. C. busses : 
 
 (a) From an external source of power : Close single circuit 
 breaker and close switch No. 2 to the right facing the board. 
 
 (b) From the casemate generator: Close single circuit 
 breaker and close switch No. 2 to the left facing the board. 
 
 (c) From the storage battery: With switch No. 2 open, 
 close double circuit breaker. 
 
 Feeder switches are plainly marked. The D. C. switches 
 supply pow r er as follows : 
 
 No. 3. When up, supplies the operating boards (negative 
 pole to boards, positive to earth) ; when down, it is spare. 
 
 No. 4. When up, supplies motor-generator No. 1 ; when 
 down, motor-generator No. 2. 
 
 No. 5. When up, supplies the mine commander's station. ' 
 
 No. 6. When up, supplies casemate lamps; when down, it 
 does the same, but the power is now drawn from an external 
 source and not from the D. C. busses. 
 
 No. 7. When up, grounds the positive bus and connects the 
 negative bus through the protective lamp and mil- ammeter 
 to the mil-ammeter lead. 
 
 The A. C. switches supply power as follows : 
 
 No. 8. When up, supplies the operating boards, one pole 
 to boards, the other to earth through an independent lead; 
 
14 SUBMARINE MINING. 
 
 when down, it does the same, but the side grounded is 
 grounded through a choke coil. 
 
 No. 9. When up, energizes the A. C. busses from motor- 
 generator No. 1 ; when down, the A. C. busses from motor- 
 generator No. 2. 
 
 No. 10 is spare. 
 
 No. 11. When up, supplies power to the primary of the 
 testing transformer; when down, it is spare. 
 
 No. 12. When up, supplies power from the secondary of 
 the testing transformer to the test fuses. 
 
 Voltmeter receptacles and plugs, all of which are properly 
 marked, are provided for obtaining the reading of the A. C. 
 and D. C. voltages. The D. C. receptacles are on the right 
 and the A. C. on the left. The first receptacle of each set is 
 spare to hold the plugs when the latter are not in use. 
 
 With the D. C. plug: 
 
 In the second receptacle, the voltage of the casemate gen- 
 erator is indicated. 
 
 In the third receptacle, voltage of external D. C. power. * 
 
 In the fourth receptacle, voltage of storage battery. 
 
 With the A. C. plug: 
 
 In the second receptacle, voltage of A. C. power on the 
 busses is indicated. 
 
 In the third receptacle, voltage of external A. C. power, 
 if the latter is supplied. 
 
 In general, no external A. C. power should be led into the 
 casemate, as the system would be unsafe, owing to the lia- 
 bility of a " cross." The standard system is perfectly safe, 
 as it is impossible for a mine to be fired when the motor 
 generators are idle. 
 
 The double circuit breaker is an ordinary single-coil 
 breaker. The single circuit breaker is an overload and 
 reverse-current circuit breaker. The reverse-current coil has 
 two windings, one of which is bridged across the power 
 supply, and the other is in series with it. On charge, the 
 effect of these coils is differential, and on discharge it is 
 cumulative and will trip the circuit breaker when the current 
 from the storage battery exceeds 2 amperes. 
 
f - 
 
 ffiUMllr 
 
 &&>&& 
 
 FIG. 3. OPERATING BOARD. 
 
SUBMARINE MINING. 15 
 
 To charge the storage battery: 
 
 (a) From an external source of power: Both the single and 
 the double circuit breakers are closed and switch No. 2 is 
 closed to the right (facing the board). 
 
 (b) From the casemate generator: Both circuit breakers 
 are closed and switch No. 2 is closed to the left (facing the 
 board). 
 
 The operating board. A front view of this is given in figure 
 3, its wiring diagram in figure 18 at the end of the book. 
 One is required for each group of 19 mines. It consists of 
 an iron frame to which are attached a signal block, a master 
 block, 19 mine blocks (1 for each mine), busses, and a ter- 
 minal bar with 19 numbered terminals. The frame is 78 
 inches high by 24 inches wide. It should be set up so that 
 its face is 34 inches from the wall in rear. 
 
 The signal block (see fig. 18). This is an enameled slate 
 block 24 inches wide and 11 inches high, upon which are 
 mounted three binding posts, three lamps (red, white, and 
 green), a bell and bell switch, a 90-ohm noninductive resist- 
 ance in parallel with the white lamp, and a 125-ohm re- 
 sistance in series with the bell. The binding posts are 
 marked " Earth " or " G.," "A. C.," and D. C.," respectively. 
 The bell, the 90-ohm non-inductive resistance, and the 125- 
 ohm resistance are so indicated on the figure. The lamps are 
 marked as follows: Red, " R. L."; white, "W. L."; green, 
 " G. L." 
 
 The circuit, under normal conditions, is: From negative 
 D. C. bus on power panel, to switch 3 closed up, to " oper- 
 ating board " terminal, to D. C. lead, to D. C. post on signal 
 block, through green lamp, to D. C. jaw on master block, to 
 D. C. bus on operating board, through power switch P on 
 mine block, through solenoid S, to middle of testing switch 
 T, to upper contact of same, to upper contact of automatic 
 switch A, to middle of same, to mine switch M, through 
 same to terminal bar, through 19-conductor and single-con- 
 ductor cables, through mine transformer primary, to mine 
 case, to ground, to D. C. " earth " terminal on power panel, to 
 switch 3, and to positive D. C. bus on power panel. 
 
16 SUBMARINE MINING. 
 
 Green lamps of 8, 1C, and 32 candlepower are supplied. 
 The 16-candlepower green lamp glows dimly when 19 mines 
 are connected to the operating board and all are free from 
 short circuits, grounds, or abnormal resistances. If it should 
 glow abnormally bright, due to grounds, a 32-candlepower 
 lamp should be substituted. If it should glow very dimly, 
 due to a less number of mines connected, an 8-candlepower 
 lamp should be used. 
 
 A short circuit in a mine circuit causes the green lamp to 
 glow more brightly. 
 
 Breaks in conductors not causing short circuits will not be 
 revealed ordinarily by this lamp. To detect breaks, tests of 
 individual mines must be made. 
 
 The red lamp glows and the bell rings when any automatic 
 switch is down. The circuit under this condition is: 
 
 From negative D. C. bus on power panel to switch 3 
 closed up, to " operating board " terminal, to D. C. lead, to 
 D. C. post on signal block, through green lamp to D. C. jaw, 
 to D. C. operating board bus, through power switch on mine 
 block whose automatic switch is down, through insulated 
 pin of lower arm of automatic switch, to lower point of 
 testing switch T, to operating board lamp bus, through bell. 
 125-ohm resistance and bell switch, and red lamp in parallel, 
 to " earth " post, to earth lead^ to D. C. " earth " terminal on 
 power panel, to switch 3, and to positive D. C. bus on power 
 panel. 
 
 The resistance of the bell is such that a resistance of 125 
 ohms must be placed in series with it to make the joint re- 
 sistance of the red lamp-bell circuit so large that if one auto- 
 matic switch is down it will not interfere with the tripping 
 of another. 
 
 The white lamp, W. L., is in the firing and A. C. testing 
 circuits. The 90-ohm resistance is in parallel with this lamp, 
 and in addition to protecting it from excessive current, serves 
 to keep the firing circuit complete should the lamp burn out. 
 
 The master block (see fig. 18). This is an enameled slate 
 block 6 inches wide by 9J inches high, upon which are 
 mounted two jaws for the terminals of a jumper, a testing 
 switch, T. S., and a firing switch, F. S. 
 
11003 12 2 
 
r -Automatic Switch 
 
 ..Mine Switch 
 
 Automatic Switch 
 Release 
 
 Power Switch 
 
 Solenoid 
 
 ' L - Testing Switch * L Solenoid Plunger 
 
 FIG. 4. MINE BLOCK. 
 
SUBMARINE MINING. 17 
 
 The testing switch, T. S., is used to determine if the A. C. 
 power be on the signal block. If so, when it is closed the 
 white lamp on signal block glows. This switch is marked 
 to indicate its " off " and " on " positions. When " on " the 
 circuit is as given in " test of the delivery of the A. C. power 
 to the operating board," Chapter VI. 
 
 The firing switch, F. S., is used to throw the A. C. power 
 on the operating board A. C. busses. This is marked to show 
 its " on " and " off " positions. No mine can be fired unless 
 this switch is in its " on " position. When " on " the firing 
 circuit is as follows: 
 
 From A. C. bus on power panel to switch 8 closed up, to 
 " operating board " terminal, to A. C. lead, to A. C. post on 
 signal block, to white lamp and resistance in parallel, to 
 A. C. jaw, through firing switch, F. S., to A. C. b,us on 
 operating board, to lower point of automatic switch when it 
 is closed down, to middle point of automatic switch, through 
 mine switch to terminal bar, through 19-conductor and 
 single-conductor cables, through mine transformer primary, 
 to mine case, to ground, to A. C. "earth " terminal on power 
 panel, to switch 8. and to other A. C. bus on power panel. 
 The white lamp glows after the mine has been fired. 
 
 The mine block (see figs. 4 and 18). This consists of an 
 enameled slate block, 6 inches wide and 9J inches high, on 
 which are mounted four switches. 
 
 1. The upper switch is the " mine switch." When it is 
 open the corresponding mine is cut out and can not be fired. 
 It is placed horizontally on the blocks of the old model and 
 vertically on those of the new model. 
 
 2. The right-hand switch, a S. P. S. T. knife switch, is 
 the "power switch." When it is closed the D. C. power is 
 on the block and the automatic switch will function when 
 the corresponding mine is struck. When it is .open the mine 
 can be fired by raising the automatic switch release, thus 
 tripping the automatic switch. 
 
 3. The central switch is the " automatic switch," a single- 
 pole double-throw switch, operated by the plunger of a sole- 
 noid. Through its lower arm there passes an insulated pin 
 
18 SUBMARINE MINING. 
 
 which, when the switch is down, makes connection between 
 two contacts to the right and left of this arm. 
 
 If for any cause the current through the solenoid rises 
 above that for which it is set (normally 0.075 ampere), its 
 plunger is drawn up and the switch is tripped. Such rise in 
 current is produced when a mine is struck, the resistance 
 through the circuit-closer circuit being far less than that 
 through the primary coil of the transformer. Such would 
 also be the case when a mine cable is grounded. 
 
 When the automatic switch is tripped, the D. C. circuit to 
 the mine is broken at its upper contact (see fig. 18) and D. C. 
 circuit through red lamp and bell is made through the insu- 
 lated through pin in the lower arm, thus giving warning. 
 If at the same time A, C. power be on the busses and the 
 firing switch on the master block be closed, A. C. will be 
 thrown on the mine through the lower contact of the auto- 
 matic switch, and the mine will be fired. 
 
 Just above the plunger of the solenoid there is a red knob 
 attached to the tripping bar of the automatic switch release. 
 This enables the automatic switch to be released by hand in 
 observation firing and in testing. 
 
 4. The left-hand switch, a S. P. D. T. switch, is the " test- 
 ing switch." It is used to test the automatic switch, which 
 should open when the testing switch is thrown down. The 
 bell switch should be opened before throwing down testing 
 switch. When the testing switch is in this position, the cir- 
 cuit being broken at its upper contact, the mine is cut out, 
 and in place of the mine there is thrown in the red lamp of 
 the signal block. The resistance of this red lamp is greater 
 than that of the mine circuit when the mine is struck, so that 
 if the automatic switch works for the current through the 
 red lamp it will certainly work for that through the circuit 
 closer when the mine is struck. 
 
 The circuit when the testing switch, T, is down and before 
 the automatic switch drops is : From negative D. C. bus on 
 power panel, to switch 3 closed up, to " operating board " 
 terminal, to D. C. lead, to D. C. post on signal block, through 
 green lamp, to D. C. jaw, to D. C. bus on operating board, 
 through power switch, through solenoid to middle of testing 
 
SUBMARINE MINING. 19 
 
 switch T, to lower point of same, to operating board lamp 
 bus L, through red lamp to " earth " post, to earth lead, to 
 D. C. " earth " terminal on power panel, to switch 3, and to 
 positive D. C. bus on power panel. The circuit, when testing 
 switch, T, is down, and after the automatic switch has dropped, 
 is the same as the above up to the power switch, then from 
 the power switch through the insulated pin in the lower 
 part of the automatic switch, to the lower jaw of the testing 
 switch, and then the same as the circuit above. 
 
 A diagram similar to the wiring diagram, figure 18, at the 
 end of the book should be made of the power panel and of 
 one of the operating boards of each casemate and posted in a 
 conspicuous place in the casemate. Any changes made in the 
 wiring of either of these boards should be made immediately 
 on this diagram. 
 
 Submarine mine cable, 19-conductor. This is an armored 
 cable about 1 inch in diameter and contains 19 insulated 
 single conductors of No. 16 American wire gauge wire (51 
 mils in dia.) . The conductors are arranged in two concentric 
 layers around a single central conductor, the inner layer con- 
 taining 6, the outer 12. One conductor in each layer is dis- 
 tinguished from the rest by some characteristic mark, as a 
 spiral white thread, a wrapping of tape, or other easily de- 
 tected mark. The marked conductor in the outer layer is 
 No. 1, that in the inner layer No. 13, and the central con- 
 ductor is No. 19. The other conductors are numbered at the 
 shore end of the cable in a clockwise direction ; at the distant 
 end in a contraclockwise direction. 
 
 Submarine mine cable, 7-conductor. In many cases the 7- 
 conductor cable now on hand can be used to advantage for 
 mine work, particularly in planting groups which do not 
 require great lengths of multiple cable. In all such cases 
 the old grand junction boxes are to be used as distribution 
 boxes, thus providing for separate groups of 7 mines. 
 
 Submarine mine cable, single conductor. This is an armored 
 cable, about three-fourths inch in diameter, and contains 
 an insulated conductor made of 7 strands of soft annealed 
 No. 22 American wire gauge copper wire (25.35 mils in dia.). 
 
20 SUBMARINE MIXING. 
 
 The buoyant-mine case. The service 32-inch, pattern is 
 made of 10-pound, ^-inch, open-hearth steel, of great tough- 
 ness and elasticity, and is thoroughly galvanized. The shell 
 consists of two hemispheres, ribbed and welded together at 
 the equator, thus avoiding all rivets. Every case before it is 
 accepted is tested with an internal hydraulic pressure of 100 
 pounds per square inch. 
 
 The top hemisphere is provided with an external man- 
 euvering ring ; the bottom hemisphere has a hole 5^ inches 
 in diameter at the pole. The edge of the hole is reenforced 
 by a welded ring 1^ inches thick ; and near it are four bosses, 
 also welded, carrying screw bolts which project 2^ inches 
 outside to secure the cap. 
 
 The cap consists of a hemisphere of 15-pound, f-inch 
 wrought iron, flanged and dished at the base to fit the case, 
 to which it is attached by the four bolts already mentioned. 
 They pass through slots in the flange, which is then held in 
 place by shoes and nuts which are keyed on. The water has 
 free access to the chamber inside the cap. The uses of the 
 cap are: To clamp the Turk's-head of the mine cable, to 
 cover and protect the portion of the core exposed outside the 
 case, and to serve as an attachment for the wire mooring 
 rope. 
 
 A hole 1-J inches in diameter at the pole of the cap is con- 
 nected by means of a slot with a 3-inch hole punched through 
 the cap between two of the bails. This arrangement per- 
 mits the entrance or removal of the Turk's-head without re- 
 moving the cap from the mine case. The mooring attach- 
 ment consists of a ring of IJ-inch wrought iron, having a 
 hole 2^ inches in diameter, attached to the cap by three bails 
 of 1-inch wrought iron permanently double riveted to the 
 sides. The cap is thoroughly galvanized. 
 
 The large hole in the mine case covered by the cap is closed 
 by a plug. The joint is made water tight by a lead washer 
 jammed between the plug proper and the case and by a coat- 
 ing of red lead or similar waterproofing material upon the 
 screw threads. In the strong currents and deep water of 
 some harbors more buoyancy than is possessed by the 32-inch 
 case is required. This is obtained by inserting between the 
 
Cop 
 
 Circuit C/oser 
 Springs 
 
 P/ate 
 
 D/3 tan ce R/ng 
 Bo// 
 
 r?eocfanc& Terminal 
 
 Transformer- 
 
 Primary Term/no/ 
 Screw 
 
 Fuse Con 
 
 Trofo/ 
 
 fuse Can Cap 
 Jef Screw 
 Lower 
 
 Set Screw 
 P/vg Proper 
 Rubber Packing 
 
 Bo// Sear 
 -Primary Term/no/ 
 
 Reinforce 
 Lead Washer 
 Brass G/ond 
 
 Lead Washers 
 
 Brass G/and 
 
 Loading W/re 
 
 FIG. 5. COMPOUND PLUG, OLD MODIEL FUSE CAN. 
 
Cop 
 
 C/rcvf C/oser- 
 Ba// 
 
 Trans for me r 
 Reactance 
 
 P/ore 
 
 Primary Co//- 
 
 Co//ar. 
 Cotter Pin 
 
 Bo/f Securing 
 
 Screws 
 
 Conn&cfing Co//or 
 Okonite and Hanson 
 Tape 
 
 Brass Jointers 
 
 Connecting Bolt 
 Rubber 
 
 Dry 
 
 Oun Co f ton 
 Primer Cokes 
 
 Rubber Pocking 
 
 h 
 
 Proper* 
 
 FIG. 6 COMPOUND PLUG, RUBBER FUSE CAN. 
 
Cop 
 
 Circuit C/oser- 
 Ball Seat 
 
 Transformer- 
 fteacfance 
 
 Pr/mory Co//- 
 Brass Co//ar 
 Colter P/'n 
 
 Plate 
 Distanc e Ring 
 
 Bo/t Securing 
 Nuts 
 
 Connecting Collar 
 Connecting 0o/t 
 
 Fuse Con 
 
 Fuses 
 
 Brass Washer 
 Lead Washer- 
 
 fuse Can Cap 
 I Rubber Pocking 
 
 ~^p- Plug , Proper 
 Rubber Packing 
 Brass Gfand 
 
 4- o a a* ing 
 
 Wire 
 
 FIG. 7. COMPOUND PLUG, TROTOL FUSE CAN. 
 
SUBMAKIKE MINING. 
 
 21 
 
 hemispheres a cylinder of 20-pound wrought iron which is 
 stiffened by extra welded ribs for the larger sizes. Such cases 
 are designated by the diameter in inches of a sphere having 
 the same buoyancy. Thus, a Xo. 40 case is made by inserting 
 a cylinder 32 inches in diameter and 20.4 inches in length 
 between the two hemispheres of a No. 32 case; this is suffi- 
 cient to make the displacement equal to that of a spherical 
 case 40 inches in diameter. In the latest types the cylinders 
 are made of corrugated mild steel of less thickness, which 
 diminishes very materially the weights of the cases. 
 
 The following table exhibits the dimensions and weights 
 of buoyant mines, with trot pi fuse cans, complete except the 
 charges and moorings. The actual free buoyancy when 
 planted will be the difference between the displacement and 
 weight as given in the table, reduced by the weight of the 
 charge and of the moorings and cables : 
 
 PLAIN CASES. 
 
 No. 
 
 Dis- 
 place- 
 ment. 
 
 Com- 
 puted 
 weight, 
 empty. 
 
 Meas- 
 ured 
 weight, 
 empty. 
 
 Length 
 of 
 cylinder. 
 
 Remarks. 
 
 32 
 
 33 
 
 Pounds, 
 635 
 
 695 
 
 Pounds. 
 308 
 
 364 
 
 Pounds. 
 311 
 
 Feet. 
 0.00 
 
 .17 
 
 All are about 33J inches in outside diameter; 
 the extreme length in each case is 4.3 feet 
 plus the length of the cylinder. 
 
 34 
 
 762 
 
 395 
 
 
 .35 
 
 
 35 
 
 829 
 
 427 
 
 
 .54 
 
 
 36 
 
 904 
 
 462 
 
 
 .75 
 
 i 
 
 37 
 
 982 
 
 498 
 
 
 .96 
 
 
 38 
 
 1,064 
 
 538 
 
 
 1.20 
 
 
 39 
 
 1,149 
 
 578 
 
 
 1.43 
 
 
 40 
 41 
 
 1,242 
 1,341 
 
 621 
 665 
 
 (525 
 
 1.70 
 1.96 
 
 
 4*> 
 
 1,436 
 
 712 
 
 
 2.24 
 
 
 43 
 44 
 
 1,540 
 1,652 
 
 788 
 842 
 
 759 
 
 2.53 
 2.77 
 
 One extra welded rib. 
 
 45 
 
 1 767 
 
 876 
 
 
 3.17 
 
 Do 
 
 46 
 
 47 
 43 
 
 1,887 
 
 2,013 
 2,144 
 
 952 
 
 1,011 
 1,073 
 
 f 899 
 \ 936 
 
 ~"i,"637' 
 
 | 3.50 
 
 3.85 
 4.20 
 
 /Lot of 1879; one extra welded rib. 
 \Lot of 1884; one extra welded rib. 
 One extra welded rib. 
 Do. 
 
 CORRUGATED CASES. 
 
 47 
 
 1,536 
 
 572 
 
 
 2.24 
 
 
 V) 
 
 2,323.2 
 
 777 
 
 
 4.22 
 
 
 
 
 
 
 
 
 The compound plug, with old model brass fuse can. A sec- 
 tion of this plug, with the names of all the parts, is shown 
 
22 SUBMARINE MINING. 
 
 in figure 5. The brass fuse can is not used when guncotton 
 is used as a priming charge. 
 
 The compound plug, with rubber fuse can. A section of this 
 plug, with the names of all the parts, is shown in figure 6. 
 
 The compound plug, with trotol fuse can. A section of this 
 plug, with the names of all the parts, is shown in figure 7. 
 
 In each plug the main parts are screwed together and held 
 in place by set screws. The connection of the compound 
 plug with the mine case makes an earth plate, of which the 
 electrical resistance in salt water is about 1 ohm. 
 
 The mine transformer (see fig. 8). This consists of a cylin- 
 drical brass case, which contains the primary and secondary 
 coils of the transformer and the reactance coil. The trans- 
 former is screwed into the brass collar or the reenforce and 
 in turn has the circuit closer screwed upon its top. The 
 fuses are attached to the secondary and are fired when proper 
 voltage is applied to the primary. The primary leads are 
 black; those of the secondary are red. The terminal, P', of 
 the primary coil is left free for the purpose of testing, but 
 when preparing the transformer for use it is attached 
 securely to the binding post, T. The upper terminal, R', 
 of the reactance is prepared for attachment to the ball seat 
 of the circuit closer. 
 
 The normal circuit is from P, 'through the primary coil 
 (the resistance of which is about 2,400 ohms), to the trans- 
 former case, and thence tto earth. However, when the mine 
 is struck, so as to close the circuit closer, a parallel circuit is 
 closed through the reactance (the resistance of which is about 
 130 ohms), thence to the ball seat of the circuit closer, 
 through the ball and springs to the transformer case, and 
 thence to earth. In this latter case, therefore, the resistance 
 is lessened by about 2,300 ohms. 
 
 The reactance coil will permit only a small amount of 
 alternating current to pass through it when the ball is dis- 
 placed, hence mines may be fired whether the ball is displaced 
 or not. 
 
 Two fuses are connected in multiple across the ends of 
 the secondary terminals. These terminals are 10 inches in 
 
REACTANCE: 
 
 PRIMARY COIL 
 
 SECONDARY 
 COIL 
 
 FIG. 8. MINE TRANSFORMER. 
 
SUBMAKINE MINING. 23 
 
 length, to allow ample margin for inserting fuses in the 
 primer. 
 
 The transformer is of the step-down type and is rated at 
 22.5 watts, 60 cycles, 500 volts primary, and 14 volts sec- 
 ondary. 
 
 The mine circuit when normal is such that 80 volts should 
 give only 30 mil-amperes, but a mine may be fired even when 
 the circuit is so defective that 80 volts give 120 mil-amperes. 
 
 Furthermore, 150 volts D. C. may be applied to the pri- 
 mary without danger of explosion. 
 
 An explosion can not be produced unless the A. C. busses 
 on the operating board are energized, and as long as the 
 firing switch on the master block is open, there is no danger 
 from accidental closing of switches in making mine tests or 
 from short circuits in the mine. 
 
 NOTE. In designing this transformer the following varia- 
 tions were considered: (a) Omitting reactance and tapping 
 to ball seat beyond primary of transformer; (b) using a 
 condenser; (c) using two sets of fuses, so as to be able to fire 
 with either D. C. or A. C. All were eliminated, as they 
 impaired either the safety, the simplicity, or the efficiency of 
 the system. 
 
 The circuit closer. This, when used with the buoyant mine, 
 consists of the following parts: The cap, the spring plate, 
 the distance ring, the steel ball, and the ball seat, which, when 
 assembled, are mounted on the top of the mine transformer. 
 
 The ground-mine case. The form and details of construc- 
 tion adopted for the service pattern are the following (see 
 fig. 9) : The case is cast iron, in form a segment of a sphere, 
 of which the height is two-thirds of the radius. The bottom 
 is nearly flat, w y ith a central sand-hole plug to empty the 
 casting. Six internal radial ribs are added to give addi- 
 tional supports to the top; the loading hole, 5J inches in 
 diameter (3 inches in old pattern), is at the pole and is 
 closed by a compound plug. Before acceptance a hydraulic 
 pressure of 100 pounds per square inch must be borne with- 
 out developing leakage. 
 
24 
 
 SUBMARINE MINING. 
 
 Only one size of ground mine has been introduced into 
 our service. This pattern is designed to contain from 200 
 to 300 pounds of explosive and to rest on the bottom in water 
 not exceeding 35 feet in depth at high tide. The dimensions 
 are as follows: Radius of the sphere, 21^ inches; diameter 
 of the base, 40 inches; extreme height, 25 inches; thickness 
 of iron, seven-tenths of an inch; weight, empty in the air, 
 1,355 pounds; when submerged it loses 515 pounds. The 
 capacity of this case is about 5 cubic feet. 
 
 A mine cap is provided to clamp the Turk's-head of the 
 mine cable, to cover and protect the portion of the core 
 
 CAP 
 GLAND 
 
 FUSE CAN 
 
 FIG. 9. Ground-mine case. 
 
 exposed outside the case, and to serve as an attachment for 
 the mooring and the raising ropes. This cap is held to the 
 mine case by six bolts, and is fitted with two rings, one for 
 attachment of the mooring rope of the circuit-closer buoy 
 and the other for attachment of the raising rope. 
 
 The compound plug, ground mine. This is similar to the 
 compound plug for buoyant mines. The circuit closer is 
 placed in a buoy above the mine. 
 
 The mushroom anchor. The 1,000-pound anchor is in shape 
 a right cylinder about 10 inches in height and 26 inches in 
 diameter, slightly dished on the bottom to increase the hold- 
 
11003 12 3 
 
FIG. 10a. AUTOMATIC ANCHOR. 
 
SUBMARINE MINING. 25 
 
 ing power in mud. For a rock bottom six projecting toes 
 increase the holding power; corresponding depressions on 
 the top permit piling when in store. The heavy anchors, 
 2,000 and 3,000 pounds, are of the same form. The cylindri- 
 cal form is adopted to facilitate handling, since in that shape 
 the anchor may be rolled readily on its edge. 
 
 The absolute stress of the mine and its moorings upon a 
 mushroom anchor of this kind is easily computed, being 
 the square root of the sum of .the squares of the buoyant 
 effort and of the horizontal pressure exerted by the current. 
 The latter, in pounds per square foot of exposed cross sec- 
 tion, may be estimated at one-half the square of the velocity 
 of the current in feet per second. A coefficient of safety 
 should cover the jerking effect of the waves and the shocks 
 of friendly vessels. It will, of course, vary with the locality 
 and with the absolute weight of the anchor, but in general a 
 value from 3 to 5 is considered sufficient. 
 
 The holding power of such an anchor varies greatly with 
 the nature of the bottom. If this be hard, the dead weight 
 alone must be depended upon ; if soft, at least double power 
 may be anticipated. In swift water the buoyant mine can 
 be better held in position by two anchors chained together. 
 
 The shackles. The wire mooring rope is attached to the 
 anchor and to the case by shackles, of which there are two 
 sizes. The anchor shackle consists of a wrought-iron strap 
 with two eyes bent into the usual curved form and offering 
 a thickness of \\ inches at the bottom, where the wear and 
 sand cutting is greatest, and of a IJ-inch wrought-iron bolt 
 fitted flush with the outside of the straps. The bolt is held 
 in position by a split key, which, after insertion through a 
 small hole in the bolt and one of the eyes (in the old model) , 
 is opened so that it can not work loose. 
 
 The mine shackle is lighter, being 1 inch thick at the bot- 
 tom, with a 1-inch bolt; otherwise it is identical in pattern 
 with the anchor shackle. 
 
 Sister hooks. They are used to connect the bail of the 
 mushroom anchor to the anchor shackle. They are of drop- 
 forged steel of high tensile strength and weigh about 7 
 pounds per pair. 
 
26 SUBMARINE MINING. 
 
 The automatic anchor, Artillery type, 1910 (see figs. 10 a 
 and b). This is a device intended for use with buoyant 
 mines, and by means of which such mines may be anchored 
 in any depth of water, with any desired depth of submerg- 
 ence given automatically. 
 
 The anchor is bell-shaped, 28 inches in diameter at the 
 bottom, 28^ inches high over all, and composed of the follow- 
 ing parts : Body, cover, reel, journal-box caps, ratchet, pawl, 
 pawl spring, distance rope, distance weight, brakes, bails, 
 necessary bolts, wrenches, and crank handles. 
 
 The pawl is drawn away from the ratchet by a weight sus- 
 pended a certain distance below the anchor. This is called 
 the distance weight, and the submergence is regulated by the 
 distance this weight is from the anchor. In falling through 
 the water the mooring rope will unreel and the mine will 
 remain on the surface, but w r hen the distance weight reaches 
 the bottom the pawl spring forces the pawl into the teeth 
 of the ratchet, and as the latter is attached to the reel shaft, 
 it prevents the reel from turning and hence unreeling. 
 
 These anchors weigh approximately 1,500 pounds, includ- 
 ing the 200-pound distance weight. 
 
 In order to control the speed of revolution of the reel, 
 the friction brakes must be adjusted properly. To do this, 
 a pull is put on the mooring rope with a spring balance 
 rigged to show the amount of pull ; the pull for a particular 
 size of case is determined by experiment. For a No. 40 mine 
 case the adjusting screws of the brake shoes are regulated 
 so that the reel will revolve slowly when a pull of 300 pounds 
 is registered. 
 
 The pawl spring is 9J inches long and of such strength that 
 a pull of 36 pounds will extend the spring 1J inches. The 
 pawl-spring bolt is of such length that the pawl spring will 
 be just at the point of tension when the top of the pawl- 
 spring bolt is flush with the top of the pawl-spring-bolt nut 
 and the pawl fully seated in the ratchet. 
 
 When the tidal currents are such as to require a heavier 
 anchor to hold the mine than the 1,500-pound automatic 
 anchor, the following combination anchor will be used: At- 
 tach a mushroom anchor by means of a mooring rope (about 
 
FIG. 105.-AUTOMATIC ANCHOR. 
 
SUBMARINE MINING. 27 
 
 8 feet long) and clips to the bail in the bottom of the auto- 
 matic anchor. If necessary, two mushroom anchors may be 
 fastened together by bolts and these attached to the auto- 
 matic anchor as stated above. 
 
 A 3,000-pound automatic anchor, similar to the 1,500- 
 pound automatic anchor, is supplied for some localities. 
 
 The mooring sockets. To connect the wire mooring rope to 
 the shackles at the mine and the anchor, a closed socket is 
 attached at each end. The eye of the socket has a clear 
 opening, 1 T % inches, designed to receive the bolt of the 
 shackle. The end of the rope is passed into the socket, 
 spread out, and secured by pouring in a melted socket alloy. 
 
 A substitute method for connecting the wire mooring rope 
 to the shackles is to bend the ends of the mooring rope by 
 means of a small vise around a galvanized-iron thimble and 
 fasten the end by two bolted clips. 
 
 Wire mooring rope. This is the highest grade of j-inch 
 galvanized-steel wire rope, consisting of 6 compound strands, 
 each made of 19 wires, the whole laid around a steel center. 
 Its breaking strength when new is about 18 tons. Its weight 
 per running foot, submerged, is about eight-tenths of a 
 pound. It is used for mooring mines to mushroom anchors. 
 
 Marline-covered wire mooring rope. For mooring mines to 
 the automatic anchors and for raising rope marline- 
 covered wire rope is used. This rope consists of five outer 
 strands wound around a central hemp core. Each of the 
 outer strands consists of a small twisted wire rope wound 
 around with four strands of marline. One end of the rope is 
 prepared for attachment to the mine by passing it over a 
 thimble and fastening it to the standing part by means of 
 two clips. A shackle joins the thimble and the bail of the 
 mine. The other end of the rope is made secure to the reel 
 of the anchor. The breaking strength of ^-inch marline- 
 covered rope is 17,000 pounds, that of f-inch marline-covered 
 rope is 27,000 pounds. The weight per running foot of the 
 |-inch rope is 0.5 pound, that of the f-inch rope is 0.8 pound. 
 The weight of this rope submerged is about 60 per cent of its 
 weight in air. 
 
28 SUBMARINE MINING. 
 
 About 155 feet of the -inch and 85 feet of the |-inch mar- 
 line-covered rope can conveniently be wound on the G-inch 
 reel of the 1,500-pound automatic anchor. 
 
 Marline-covered wire distance weight rope. For attaching 
 distance weights to the automatic anchor J-inch marline- 
 covered wire rope is used. This rope is identical in pattern 
 with the marline-covered wire mooring rope. 
 
 The distribution box, 19-conductor. This is a circular, cast- 
 iron, disk-shaped box which receives the end of the multiple 
 cable, in which taped joints are made between the separate 
 conductors of this cable and the single-conductor mine 
 cables, and from which these mine cables radiate. It is 
 about 27 inches in diameter and weighs about 300 pounds. 
 It consists of two parts, a bowl-shaped bottom 6 inches deep 
 inside and a slightly curved lid. The latter has an iron ring 
 in its center by which the box is raised and lowered. 
 
 Eight pins, fastened to the bottom, fit in corresponding 
 holes in the edges of the lid and are slotted for keys by 
 which the two parts are fastened together. 
 
 The vertical edge of the bottom is cut with 20 slots, each 
 about 2J inches deep. One of these is larger than the others 
 and receives the multiple cable ; the others are for the single 
 conductor cables. When in use these slots are numbered 
 clockwise from the multiple-conductor slot, looking down 
 into the box. The lid has corresponding projections or lugs 
 which enter these slots, and which, in position, fit snugly 
 against the cable ends. The cables are held from being 
 pulled out by Turk's-heads worked upon them. 
 
 To prevent the cable ends from accidentally slipping out 
 of the slots while joints are being made between them before 
 the lid is put on, the multiple cable is secured by a bolted 
 collar on the inside of the box, the single-conductor cables 
 by clipping their Turk's-heads under claw-like radial projec- 
 tions cast upon the inside rim between the slots. 
 
 The distribution box, 7-conductor. This box is used with 
 multiple cable, 7-conductor. It consists of two circular plates 
 of cast iron 21 inches in diameter and three-fourths of an 
 inch thick united by four 1-inch bolts, which are placed in 
 rounded projections forming the angles of a square. The 
 
SUBMARINE MINING. 29 
 
 cables are separately clamped, the top plate overlapping the 
 clamp straps. The multiple cable enters on one side; three 
 single-conductor cables enter on the opposite side, and two 
 on each of the intermediate sides. The top plate is provided 
 with a lowering ring. 
 
 The junction boxes. These boxes, in different sizes, are 
 used in splicing multiple and single-conductor cables; they 
 consist of two rectangular plates of iron or steel united by 
 four ^-inch bolts at the corners. The plates are hollowed 
 in the middle to form a chamber to receive the Turk's-heads 
 and the joints connecting the conductors. The ends of the 
 plates are curved to admit the cable ends. The Turk's-heads 
 are clamped to the lower plate by straps and screw bolts, the 
 cavity of the upper plate covering them when bolted in posi- 
 tion. Each cable end is thus made fast before the box is 
 closed. 
 
 The distribution-box buoy. This buoy is used to mark the 
 position of the distribution box during the planting of mines 
 and subsequently, in practice and in service, until such time 
 as the mine commander desires to remove it. It may be 
 either a can or a keg buoy a beer keg of one-half barrel 
 capacity is well suited for this purpose. 
 
 The mine buoy. This buoy is used to mark the position of 
 the mine when planted. It may be a small can buoy, prefer- 
 ably cork filled, or a piece of wood with a hole bored through 
 it. The size of the buoy is determined by the swiftness of 
 the current. It is attached to the maneuvering ring of the 
 buoyant mine by 60 feet of J-inch rope. 
 
 The measuring reel and frame. The frame consists of two 
 longitudinal pieces, 3 by 4 by 66 inches, placed 17 inches 
 apart, center to center. At 11 J inches from each end two 
 cross pieces, 3 by 4 by 20 inches in length, are fastened to the 
 longitudinal pieces with through bolts. At the center point 
 of these cross pieces are placed standards, 3 by 4 by 16f 
 inches, which have journals for the axle of the reel, counter- 
 sunk in their upper ends. Two iron braces, one on each side, 
 hold each standard firmly in a vertical position. An iron 
 clamp is also attached to the upper ends of the standards, by 
 nueans of which the axle is prevented from jumping out of 
 
30 SUBMARINE MINING. 
 
 the journals. Distance from center to center of standards is 
 43 inches. 
 
 The iron axle of the reel is 1^-inch round iron, 54 inches in 
 length. At each end of the axle a screw thread is cut for the 
 nut which holds the crank in place. Inside the screw thread 
 the axle is squared to receive the socket of the crank. Two col- 
 lars prevent the wooden reel from binding on either stand- 
 ard. The cranks are of the usual design. The drum of the 
 reel is 8^ inches in diameter; heads are 2J inches thick, 
 made in two layers, cross-grained, and are 24 inches in diam- 
 eter; length of drum over all is 36 inches. Iron plates are 
 fastened in the center of each head, through which the axle 
 passes. The reel is prevented from turning on the axle by 
 keys. 
 
 Three f-inch rods pass through the iron plates and drum 
 and bind these parts firmly together. 
 
 At 6 inches from the ends of the longitudinal pieces a hole 
 is bored to receive a lag screw, -J inch by 6 inches, by means 
 of which the whole apparatus can be firmly fastened to the 
 deck. 
 
 The brake is a piece of 3 by 3 by 36 inch hardwood, used 
 as a lever to bring pressure on the drumhead. There is one 
 for each side, and, when not in use, each rests on one of the 
 longitudinals, being held in place at one end by two staples 
 and at the other end by a bolt and pin. 
 
 Near the drum on one head is a hole through which the 
 inner end of the measuring line can be passed and stapled to 
 the outside of the head. 
 
 The cable-reel frame. The frame is made in two parts 
 which, when in use, are held in proper relative positions by 
 means of two iron ties provided with turnbuckles at their 
 centers. The ends of these ties are bent over at right angles 
 and fit in sockets in the two end parts. 
 
 Each end part consists of a standard having an iron head 
 through which works a screw turned by a small lever, the up- 
 per end carrying a journal in which the end of the reel axle 
 rests. The lower end of the standard rests on a horizontal 
 piece and has a diagonal brace on each side, the outer ends 
 of these braces being dovetailed into the longitudinal piece 
 
SUBMARINE MINING. 31 
 
 and the inner ends into the standard near the top. Dove- 
 tailed into the longitudinal piece at its middle point is a piece 
 extending out at right angles, bottom flush with bottom of 
 the longitudinal. A diagonal brace similarly fastened pre- 
 vents any outward movement of the standard. The whole is 
 held firmly together by bolts and lag screws. 
 
 Lag screws are also provided, by means of which the ends 
 of the frames can be fastened to the deck of the vessel if 
 desired. 
 
 The reel axle is 2J by 2| inch squared iron, rounded at 
 the ends for 6 inches to fit the journals of the frame. A 
 disk secured by a set-screw at one end of the axle and the 
 friction brake wheel at the other end hold the axle in position 
 with respect to the reel. 
 
 The brake wheel is 18 inches in diameter. The friction 
 band is 1^ inches by -J inch, and is fastened at one end to one 
 of the standards of the frame. The other end is attached to a 
 lever whose fulcrum is also attached to the same standard. 
 
 Boat telephones. The different models in use are as fol- 
 lows: 
 
 (a) Model 1904. The system consists of two telephone 
 hand sets, a buzzer, and a battery of dry cells of about 8 
 volts, all connected in series by means of cable and earth 
 connections. 
 
 In operating the telephones a call is made by pressing the 
 button, and when talking the lever is held down. 
 
 (b) Model 1906. The system consists of two telephone 
 hand sets, a reactance coil, and a source of energy that will 
 furnish about 15 volts, dry cells preferred, connected as 
 shown in figure 11. The terminals do not have to be poled, 
 as the receiver is not in the primary circuit and can not be 
 demagnetized. 
 
 To regulate the buzzer, remove the cap in the base nnd 
 with a small screw driver loosen the lock nut on the center 
 screw (a small portion of a turn is all that is necessary). 
 With a smaller screw driver the screw may be adjusted to 
 increase or decrease the rate of vibration, increasing or de- 
 creasing the sound. Then tighten the lock nut. In case the 
 contact is dirty the entire buzzer and condenser may be 
 
32 SUBMARINE MINING. 
 
 removed by disconnecting the cord and removing the screw 
 on the back of the telephone just below the call button. As 
 the contacts are aluminum, this will seldom have to be done. 
 
 (c) Model 1909. The system consists of two telephone 
 hand sets, an apparatus box, and a battery of from 7 to 10 
 volts, all connected as shown in figure 12. The talking and 
 ringing circuits are normally open at the talking and ring- 
 ing buttons, respectively. 
 
 Apparatus box. Seven dry cells in series should be con- 
 nected to the posts of the apparatus box marked " + " an d 
 " ," and the post marked " G " connected to a ground plate. 
 
 /Shore hand set. The blue cord of the shore hand set should 
 be connected to the ground plate. Either of the red cords 
 of the shore hand set should be connected to the post in the 
 apparatus box marked " L " and the other to the conductor 
 in the cable that is to be used for telephoning purposes. 
 
 Boat hand set. The blue cord of the boat hand set should 
 be connected to the ground plate and one of the red cords 
 to the conductor in the cable to which the hand set on the 
 shore is connected. The other red cord is free. 
 
 Signaling. From figure 12 it will be seen that in either 
 hand set, when neither the ringing nor the talking switch is 
 closed, a condenser within the hand set is in series with the 
 transmitter and the receiver, so that the practical effect is to 
 permit an alternating or variable current to pass through the 
 transmitter and the receiver, but to prevent a direct or con- 
 tinuous current from so doing. 
 
 By pressing the ringing key of either hand set the circuit 
 in that hand set is closed through the 1,000 ohms resistance 
 and the receiver to ground. Thus, when the ringing key of 
 the boat hand set is pressed, this allows the direct current 
 from the battery to pass (see fig. 12) through f, e, d, c, " B," 
 b, a, line, the ringing key, 1,000-ohm resistance, and receiver 
 of the boat hand set, to ground, and back through o and p 
 to battery. Similarly, a circuit through the battery, f , "A," 
 and a, is made, thus placing relays "A" and " B " in parallel. 
 The relay " B " operates, but relay "A," being less sensitive 
 than " B." does not operate. Relay " B " closes the circuit at 
 1, and thus completes the circuit from battery through f, e, d, 
 
ll 
 
 *if 
 
 3^ 
 
 LAA. 
 
 i 
 
 b 
 
 
 5, 
 
 * 
 
 SI i| ' 
 
SUBMARINE MINING. 33 
 
 c, k, 1, " C," o, p, back to battery. This causes relay " C " to 
 operate and to complete a local circuit from battery through 
 f , e, d, k, m, s, primary, t, vibrator, p, back to battery, causing 
 the vibrator to vibrate and inducing in the secondary wind- 
 ing of the induction coil an alternating current, which passes 
 through the 1 M. F. and 2 M. F. condensers, through the hand 
 sets in parallel, and by alternately increasing and decreasing 
 the attraction of the receiver magnets for their diaphragms 
 produces a loud humming sound in each receiver. 
 
 Similarly the shore station may call the boat station. 
 
 Talking. When the ringing key is released and the talk- 
 ing key is depressed the 1,000- ohm resistance is cut out and 
 the condenser in the hand set is short circuited. The current 
 is then sufficient to operate relay "A," and this relay in 
 operating allows the other relays to resume their normal 
 positions. 
 
 When the variations in the pressure upon the transmitter 
 diaphragm in either hand set varies the resistance of the cor- 
 responding branch circuit a slight variation in the current 
 from the batltery is produced. The internal resistance of the 
 battery is sufficient to produce a slight variation in its ter- 
 minal voltage. The resulting variations in the line voltage, 
 and hence in the drop across the receivers, produce the usual 
 vibrations in the receiver diaphragms. These variations also 
 produce slight variations in the current through the primary 
 winding of the induction coil, resulting in greater variations 
 across the terminals of the secondary winding. Since the 
 secondary winding is in series with the battery, the practical 
 effect is to amplify the variations in the line voltage, and 
 hence in the talking currents. 
 
 Successful working of the relays is obtained only by a 
 careful adjustment of the screws which regulate the throw 
 of the armatures. The relay "A" is located in front of the 
 " + " battery post, the relay " C " in front of the " G " post. 
 
 In addition to the above materiel there are necessary 
 for the mine system certain electrical instruments, as well 
 as tools, appliances, and supplies requiring no special de- 
 scription, which are enumerated in the supply list. (Ap- 
 pendix 8.) 
 
 Figures 17a and 17b, at the end of the book, show the con- 
 struction of an improvised mine target. 
 
 11003 12 4 
 
CHAPTEE III. 
 LOADING ROOM DUTIES. 
 
 Making a telegraph joint. The insulation is removed from 
 the ends for 1-J inches and the wires brightened. The ends 
 to be joined are placed across each other about one-third 
 distance from the insulation, making an angle of about 
 45 with each other. The wires are grasped firmly at 
 the junction and each free end wound tightly around the 
 other wire for four turns ; the winding should be in opposite 
 directions. The ends of the wires are trimmed down so they 
 will be smooth and present no sharp points. 
 
 When wires are joined with brass jointers three-fourths 
 inch of each wire is bared and the wires are inserted in the 
 jointer; each end is crimped with pliers in the direction of 
 the longer axis; the rest of the jointer is crimped and the 
 ends or sharp points rounded off. When brass jointers are 
 used care should be exercised not to crimp them too hard, as 
 the wires may be partly cut through and finally broken. 
 Special care must be used with the fuse leads, as the second- 
 ary circuit of the mine transformer can not be tested after 
 the compound plug is assembled. 
 
 Insulating a joint. A piece of rubber tape about 2 inches 
 long is used, with ends cut diagonally. The tape is stretched, 
 and starting at a point about three- fourths inch back on the 
 insulation, with the long edge of the tape on the inside, it is 
 wound around the joint under tension, each turn covering 
 the previous turn about one-third. The wrapping is con- 
 tinued until the same amount of insulation is covered on each 
 side, when the wrapping is worked backward over the joint 
 and the end is secured by pressing it firmly a short time or 
 placing a drop of cement under it. 
 34 
 
SUBMARINE MINING. 35 
 
 Making a water-tight joint. The two ends of wire are 
 scraped clean for about three-fourths of an inch and joined 
 by a brass jointer, which is then crimped. The insulation is 
 scraped clean about 2 inches on each side of the jointer and 
 covered with rubber cement. (Cement is not absolutely 
 essential.) Two strips of rubber tape are cut about 6 inches 
 long, with diagonal ends, and stretched. Beginning about 
 1J inches along the insulation, the tape, with the long edge 
 on the inside, is wrapped firmly and tightly until about one- 
 fourth of an inch of the insulation on the other side is cov- 
 ered ; it is wound back and forth over the joint so as to taper 
 toward the ends. The other piece of tape is used, beginning 
 at the other end and wrapping as before. The finished insu- 
 lation should be thick at the middle and taper toward the 
 ends. It should be firm and tight. The insulation is cov- 
 ered with tin foil, wrapped with protective tape, and vulcan- 
 ized for about 30 seconds. The protective tape and tin foil 
 are then removed, the joint inspected, and new protective 
 tape wrapped on, using two pieces, starting at opposite ends 
 and finally ending each beyond the center. 
 
 Making a Turk's-head. The cable is trimmed square and a 
 wrapping of four or five turns of marline is made about 15 
 inches from the end. The collar, flat side first, is slipped 
 on until it rests on the marline ; the iron wires are bent back 
 regularly over the collar. The jute wrapping is unwound 
 to the collar and trimmed, and all the iron wires are cut with 
 the pliers, removing all but 4 inches and 6 inches from 
 alternate strands; the iron wires are bent separately to fit 
 the collar closely (making two right angles with the pliers), 
 and the ends arranged smoothly along the cable; the end of 
 a piece of marline is engaged under one of the wires near 
 the collar and wrapped regularly and closely around the 
 cable, and the free end of marline secured with two half 
 hitches. About 15 feet of marline are required for single 
 conductor cable ; 24 feet for multiple cable. 
 
 Testing fuses. The following apparatus is used for testing 
 in the loading room: A double-pole double-throw switch, a 
 
36 SUBMARINE MINING. 
 
 150- volt voltmeter, and sufficient dry cells to give a full throw 
 when using the lower scale of the voltmeter. The apparatus 
 is connected up on the testing table so as to make resistance 
 measurements by the voltmeter method. To test fuses, leads 
 are carried from the switch to an iron or other suitable recep- 
 tacle outside of the building and the fuse leads joined 
 thereto. A full deflection should be obtained when the cir- 
 cuit is closed through the fuses. 
 
 Preparing a compound plug for service. The transformer to 
 be used is first tested for a good circuit between the red wires, 
 a poor circuit between the ends of the black wire, a good cir- 
 cuit between the black or primary lead and the reactance 
 terminal, no circuit between the red and black wires, and no 
 circuit between any wire and the case. The resistance of the 
 circuits is determined by the voltmeter method. The upper 
 end of the black wire (see fig. 8) is prepared for use by 
 baring the wire for about one-half inch and securing it to 
 the binding post in the neck of the transformer. The ball 
 seat is screwed home. The spring plate, distance ring, and 
 ball are placed in the circuit-closer cap, which is held in- 
 verted and the transformer screwed into it, the threads being 
 coated with ruberine. 
 
 (a) Old model, brass fuse can. Starting with the compound 
 plug dismantled. 
 
 A piece of loading wire is cut about 3 feet long and the 
 ends bared. One end is joined by a telegraph joint to the 
 primary terminal of the transformer and the joint is taped. 
 This wire and the two secondary wires are drawn through 
 the fuse can, which is screwed on the transformer, the threads 
 of the latter having first been coated with ruberine. 
 
 Two mine service fuses, which have been tested for con- 
 tinuity of circuit, are connected in multiple across the sec- 
 ondary (red) terminals and the joints taped. 
 
 The can is held vertically and the explosive, if trotol, 
 poured in up to the screw threads for the fuse-can cap; if 
 dynamite, inclosed in a cloth bag and placed in the can. 
 The fuses are embedded in the explosive. 
 
SUBMAKINE MINING. 37 
 
 The loading wire is drawn through a lead washer and the 
 fuse-can cap ; the latter, its threads having been coated with 
 ruberine, is screwed into place. 
 
 A rubber packing is pushed over the loading wire into the 
 stuffing box in the fuse-can cap, a brass gland is threaded 
 down so that it is close against the rubber packing, and the 
 follower in screwed home with moderate pressure. The 
 lower tube is screwed into place, compressing a lead washer 
 between it and the fuse-can cap. The threads of the follower 
 and lower tube are coated with ruberine. 
 
 The loading wire is drawn through a lead washer and the 
 hole in the plug proper, and the latter screwed hard against 
 the lower tube. 
 
 A rubber packing and a brass gland are placed upon the 
 loading wire and forced into their seat in the plug proper by 
 means of the follower, the threads of which have been coated 
 with ruberine. 
 
 (b) Rubber fuse can. Starting with the compound plug 
 dismantled. 
 
 Two mine service fuses, which have been tested for con- 
 tinuity of circuit, are cut with 9-inch leads, wires bared for 
 about 1 inch and connected in multiple. A piece of loading 
 wire is cut about 3 feet long and the ends bared for telegraph 
 joints. It is threaded through a hole in a cake of dry gun- 
 cotton. The tw T o fuses are inserted by pushing each sepa- 
 rately into the same hole and the loading wire drawn up 
 until it is the same length above the cake as the fuse leads. 
 
 Three other primer cakes are threaded on the wire; two 
 above the fuses, and one below. This arrangement will leave 
 the fuses in the third cake. The cakes are held in one hand 
 with the fuse leads upright, and the fuse can slipped over the 
 cakes, being careful to thread the fuse leads and loading 
 wire through the opening. 
 
 The screw threads of the fuse-can cap are covered with 
 ruberine and it is screwed firmly into place onto the fuse can. 
 The stuffing box of the cap is assembled. 
 
 The plug proper is held upright in a vise. The fuse can, 
 the threads of the cap having been coated with ruberine, is 
 
38 SUBMARINE MINING. 
 
 screwed home and secured by its set screw. The loading 
 wire must be pulled through the opening in the plug proper 
 with extreme care. It must not be injured in placing the 
 fuse can in position and in screwing it home. The trans- 
 former leads are cut about 6 inches long, and the ends bared 
 for 1 inch. The brass collar is screwed on the transformer ; 
 a little ruberine on the screw threads facilitates the opera- 
 tion. The connecting collar is slipped over the fuse leads 
 and loading wire and allowed to rest on the fuse can. The 
 transformer is supported by allowing two of the connect- 
 ing bolts to slip into the holes in the collar; telegraph joints 
 or brass jointers may be used between the secondary leads 
 and the fuses and between the primary lead and the loading 
 wire. The joints are wound with rubber tape, care being 
 taken that there are no sharp ends to cut through the tape. 
 
 The transformer is raised vertically above the fuse can 
 until the lead wires are extended. It is lowered and at the 
 same time the leads are coiled in the base of the transformer. 
 As the transformer and collar approach their position on 
 the connecting bolts, the connecting collar is screwed on the 
 transformer, the threads of the transformer having been 
 covered wih ruberine. The connecting collar will take care 
 of the remainder of the leads and joints. The set screw in 
 the connecting collar is screwed home; the brass collar is 
 placed on the connecting bolts and secured in position by the 
 nuts and cotter pins. 
 
 The lips of the fuse can and connecting collar are covered 
 with a thin covering of rubber cement. A piece of rubber 
 tape is cut about 18 inches long and laid around this opening 
 without stretching. A piece of protective tape is cut about 
 18 inches long and laid over the rubber tape with consider- 
 able stress. This forces the soft tape over the lips on the con- 
 necting collar and the fuse can and makes a tight but flexible 
 joint. The stuffing box in the plug proper is prepared as 
 under (a). 
 
 Great care must be taken not to injure the insulation of 
 the loading wire in tightening up the follower in the stuffing 
 box of the fuse can or of the plug proper. 
 
SUBMAKINE MINING. 39 
 
 (c) Trotol fuse <can. Starting with the compound plug 
 dismantled. 
 
 Two mine service fuses, which have been tested for con- 
 tinuity of circuit, are cut with 12-inch leads, the wires bared 
 for 1 inch and connected in multiple. A piece of loading 
 wire is cut about 3 feet long and the ends bared for telegraph 
 joints. The loading wire is threaded through the fuse can 
 and cap. The threads of the fuse can are covered with 
 ruberine. The can is screwed into the cap. The threads of 
 the connecting collar are coated with ruberine and the collar 
 is screwed down entirely. The loading wire should project 
 about 4 inches above the connecting collar. The stuffing box 
 of the cap is prepared. The plug proper is held upright in 
 a vise. The fuse-can cap, its threads having been coated 
 with ruberine, is screwed firmly into the plug proper by 
 means of a spanner wrench. The loading wire must be 
 pulled through the opening in the plug proper with extreme 
 care. It must not be injured in placing the fuse can in 
 position and screwing it home. 
 
 The fuses are inserted in the fuse can, which is filled with 
 trotol to the top of the connecting collar. The transformer 
 leads are cut 4 inches long and the ends bared for 1 inch. 
 The threads of the brass collar are covered with ruberine. 
 It is screwed on the transformer. The latter is raised verti- 
 cally above the fuse can and lowered on the connecting bolts. 
 
 Telegraph joints are made between the secondary leads 
 and the fuses and the primary lead and the loading wire. 
 The joints are wound with rubber tape, care being taken that 
 no sharp ends cut through the tape. The leads and joints 
 are coiled in the base of the transformer. The connecting 
 collar, its threads having been covered with ruberine, is 
 screwed upon the transformer against the brass collar. The 
 bolt-securing nuts and cotter pins are placed in position. 
 The stuffing box in the plug proper is assembled as under (a). 
 
 The actual resistance of the assembled plug in the vertical 
 and the horizontal positions is determined by testing with 
 a voltmeter. 
 
40 SUBMARINE MINING. 
 
 In service, after the loaded plug tests out satisfactorily, all 
 set screws are set up. 
 
 When compound plugs are prepared for drill or for in- 
 struction purposes the use of ruberine or other waterproofing 
 material on the screw threads is omitted ; care must be taken 
 that the transformer leads are not needlessly shortened. 
 
 Loading 1 a mine. The mine case is carried from the store- 
 room to the loading room and placed on a loading skid or 
 other receptacle with the loading hole up. The plug is re- 
 moved and the screw threads are thoroughly cleaned. The 
 explosive detail brings in a box of explosive from the explo- 
 sive house and inserts a loading funnel into the loading hole. 
 The charge for a 32-inch mine case is 100 pounds of explo- 
 sive. For the larger cases, the charge should be the maxi- 
 mum that the conditions warrant ; it is specified at present as 
 200 pounds, though larger charges are desirable if enough 
 explosive can be obtained and the excess buoyancy of the case 
 will warrant the use of more than 200 pounds. The car- 
 tridges of dynamite, the trotol, or the blocks of guncotton are 
 inserted by hand and so placed in the mine case that there 
 will be ample room for inserting the compound plug. Only 
 one box of explosive for each mine being loaded is brought 
 into the loading room at one time. After the proper amount 
 of explosive has been placed in the mine case the screw 
 threads are thoroughly cleaned with button brushes and then 
 coated with ruberine or other material to prevent access of 
 water. The compound plug, with its screw threads similarly 
 coated, is screwed home with the socket wrench, a lead washer 
 being used between the plug and mine case. A bar put 
 through holes in the sides of the skids and through the 
 maneuvering ring will prevent the case from falling over and 
 from turning while the compound plug is being screwed 
 home. 
 
 In order to insure setting the compound plug tight, it is 
 advisable to tap the end of the lever of the socket wrench a 
 few times with a large mallet or a large wooden bar. The 
 mine cap is bolted on and the mine put in a tank for test. 
 If time admits, it may remain in the water 24 hours. It 
 
SUBMAKINE MINING. 41 
 
 should show practically the same resistance as the compound 
 plug. If this test be made, the loading wire must be long 
 enough for this purpose. 
 
 Upon completion of this test the mine is taken from the 
 tank, the loading wire pushed inside the cap to avoid injury 
 in handling, and the loaded mine taken to the planting wharf. 
 
 The precautions to be observed in handling explosives and 
 loading mines are given in Appendix 1. 
 
CHAPTEK IV. 
 
 LOCATING DISTRIBUTION BOX, LAYING MULTIPLE 
 CABLE, AND MARKING OUT MINE FIELD. 
 
 (NoTfc. The operations in Chapters IV and V are described in 
 what is thought to be the logical order, but circumstances may alter 
 their sequence, and, in fact, several of the steps may be carried on 
 simultaneously. ) 
 
 For the work on the water there will be needed five boats, 
 viz, a mine planter or suitably fitted-up heavy tug, a small 
 tug or heavy launch called the distribution-box boat 5 and 
 three launches or yawls. The capacity of the planter is such 
 that a group of 19 mines can be handled at one time. 
 
 The instructions to be observed by the master of a mine 
 planter in marking out a mine field and in planting mines 
 are to be found in Appendix No. 6. 
 
 Determining location for distribution box. From an exami- 
 nation of the chart, or of the approved scheme for mining, 
 the locations of the lines and groups of mines are deter- 
 mined. A distribution box is to be placed about 350 feet in 
 rear of the center of each group of mines. The locations for 
 the distribution boxes are marked on the plotting board and 
 their azimuths from each of the ends of the horizontal base 
 or their azimuth and range from the vertical base station are 
 determined. 
 
 Marking location of distribution box. An anchor with buoy 
 attached is placed upon the deck of a small tug and carried 
 out to one of the selected spots. By a system of signals the 
 boat is directed to the location determined and there the 
 anchor is thrown overboard. The locations for the other 
 distribution boxes are marked in a like manner. 
 
 Laying multiple cable. The cable reel is placed upon the 
 forward deck of the planter and raised on the jacks. The 
 
 42 
 
SUBMARINE MINING. 43 
 
 planter then proceeds as near the mining casemate as the 
 depth of water permits, and one end of the cable is passed 
 ashore, either by a launch, by yawls, or by any other suitable 
 method. In case the planter can not approach nearer the 
 shore than 100 yards it will be necessary to coil more than 
 enough cable to reach the shore in a figure of eight in a 
 yawl, which is then towed toward the desired point on shore, 
 the men aboard the yawl paying out the cable as it proceeds. 
 This end is drawn in through the conduit or gallery to the 
 casemate or terminal hut. It may be secured by taking a 
 telegraph hitch around it with a chain and spiking the chain 
 to some heavy timbers or fastening it to some holdfast. 
 When cable ends have already been laid they will be picked 
 up and joined to the multiple cable for the groups. 
 
 The shore end having been secured, the planter moves out 
 to the position of the distribution box, unreeling the cable 
 as it goes. If the water be very deep, a friction brake must 
 be extemporized to prevent the reel from overrunning. 
 (While the planter is laying the cable, the casemate party 
 tags and attaches the shore end as explained later.) To pre- 
 vent kinks as far as possible cable should be laid with as 
 much tension as practicable. 
 
 If the cable is not long enough, a second one must be 
 joined to it. This is preferably done by passing the ends to 
 a small boat. The junction is made, either using a junction 
 box with Turk's-heads and taped joints, or opening back the 
 armor for about 5 feet from the ends, making taped joints, 
 protecting them with tape, and then rewrapping the armor 
 and seizing the ends with wire. Care must be taken to join 
 the proper conductors of the two ends. 
 
 In the meantime the distribution-box boat with a detach- 
 ment of one noncommissioned officer and five men takes the 
 distribution box and moves out to the spot marked by the 
 buoy. It picks up the buoy and makes fast to the anchor 
 line. 
 
 The planter continues laying the multiple cable until it 
 reaches the distribution-box boat. The multiple cable is then 
 cut and the end passed to the distribution-box boat, usually 
 by a heaving line. The cable is lashed to the boat ; a Turk's- 
 
44 SUBMARINE MINING. 
 
 head is worked upon the end and then secured in the distri- 
 bution box. As a precautionary measure for the recovery of 
 the distribution box, should it be lost overboard during mine 
 planting, it is well to have the multiple cable buoyed about 
 100 yards in rear of the distribution box. 
 
 In case it may be desired not to use the distribution box at 
 once, the separate conductors of the multiple cable should be 
 tagged, tested, and insulated. The cable should be buoyed 
 and dropped overboard to be recovered subsequently. 
 
 Identifying-, tagging, and testing the conductors of the mul- 
 tiple cable. Tagging. In the casemate the conductors are 
 separated, carefully identified, tagged, and attached to the 
 corresponding terminal of the terminal bar on the operating 
 board. The mine switch for No. 19 is opened and the tele- 
 phone terminal attached to its stud so as to use No. 19 for 
 communicating with the distribution-box boat. The ends in 
 the distribution-box boat are separated, one terminal of a boat 
 telephone is attached to No. 19, and the other earthed either 
 by attaching to the cable armor or to an earth plate hanging 
 overboard in the water. Communication is thus established 
 with the operator in the casemate. Nos. 1, 13, and 19 are 
 picked out easily; the remaining ones are tagged in contra- 
 clockwise direction. 
 
 Verifying the tagging. The casemate is then notified that 
 the boat party is ready to check the tagging. This is done as 
 follows : The power switches on the operating board are all 
 closed, except 19, and direct current put on the cable by closing 
 switch No. 3 up. The casemate operator then directs the boat 
 party to earth in regular succession the various conductors. 
 This is done most quickly by touching the conductor to the 
 cable armor. The corresponding automatic switch on the 
 operating board should drop. Any errors in tagging de- 
 tected by this test should be corrected at once. This test also 
 checks the continuity of circuit of each conductor. 
 
 Insulation test. The operator then directs the boat party 
 to prepare the cable end for insulation test. This is done by 
 separating the conductors, holding them in the air, and 
 drying them if necessary. 
 
SUBMARINE MINING. 45 
 
 When prepared, word is sent to the casemate operator, who 
 tests as follows : He closes switch No. 7 up. This throws D. 
 C. power on the mil-ammeter plug of the operating board 
 and introduces in the circuit the mil- ammeter and its protec- 
 tive lamp. The green lamp is then unscrewed and the mil- 
 ammeter plug used on the D. C. jaw. 
 
 If there be no leak in the multiple cable, since the ends at 
 the distribution-box boat are held in the air, there will be no 
 appreciable reading of the mil-ammeter. 
 
 If there be a leak, this fact will be revealed by a reading 
 on the mil-ammeter. To discover the particular conductor 
 or conductors on which this leak exists, each power switch is 
 opened in succession and the mil-ammeter plug inserted on 
 the jaw of the power switch. 
 
 No. 19 is now tested in the same way by first shifting both 
 telephones to No. 1, the boat end being held in the air. The 
 operator reports the result of the test. 
 
 Upon completion of these tests the power is turned off. 
 Post power should not be used for testing, because the nega- 
 tive side of the post power may be grounded. 
 
 Marking 1 out the mine field. In using automatic anchors it 
 is not necessary to mark the mine field ; but in using mush- 
 room anchors it is generally done. The material required 
 consists of 1 measuring line with reel and frame, 5 anchors, 
 5 keg buoys, and 5 raising ropes. 
 
 A buoyed anchor is dropped about 350 feet in front of 
 the distribution-box buoy. This marks the position of mine 
 No. 10 and of the center of the group. * 
 
 This marking buoy is picked up by a launch which makes 
 fast to the anchor rope. The planter now passes to the 
 launch one end of a measuring line, which has marks at 
 280, 300, 350, 580, and 600 feet. These marks may be made 
 by painting 3 feet of the measuring line some distinctive 
 color at the designated points. The planter moves out 
 slowly along the line to be occupied by the mines, unreeling 
 the measuring line as it goes, and drops buoys at the 300 and 
 600 foot marks. It then returns and does the same for the 
 other side of the line. These five buoys mark the line to be 
 
46 SUBMARINE MINING. 
 
 occupied by the mines, indicate the positions of mines Nos. 
 4, 7, 10, 13, and 16, and in addition cut up the distance into 
 300-foot lengths, which enable the planter to plant mines at 
 a close approximation to 100 feet apart. 
 
 Taking soundings on line of mines. When automatic an- 
 chors are used, such information as may be required about 
 depth of water may usually be obtained from charts. This 
 may not be sufficiently accurate for planting with ordinary 
 anchors. In the latter case .soundings must be taken at the 
 spots where the mines are to be planted. 
 
 These soundings are made from the launches. The 
 launches take a measuring line marked at every 100 feet, 
 stretch it between the planted buoys, and take the soundings 
 at every 100- foot point. The soundings are recorded in a 
 blank book showing the number of the corresponding mine 
 and state of the tide. It may be found more satisfactory to 
 hold one end of the measuring line at the buoy and circle 
 across the line of mines with the launch, getting the sound- 
 ing at the point of crossing. 
 
 Preparing mooring ropes. The mooring ropes are cut off 
 with square ends, and the ends passed through the holes in 
 the mooring sockets. The strands and wires are untwisted 
 and spread out for a length equal to the length of the socket 
 hole. The rope is pulled back until the ends are about flush 
 with the top ends of the hole ; a piece of marline is tied about 
 the rope below the socket. If necessary to hold the socket, 
 a piece of burlap may be wrapped around below the socket, 
 and a fold allowed *to fall over the hand. Generally, means 
 can be found to set the socket upright while pouring full of 
 alloy. The alloy consists of 9 parts of lead and 1 part of 
 antimony melted together. A melting pot heated by a 
 plumber's furnace, or preferably a Khotal lamp, is used for 
 this purpose. Great care must be taken to see that there is 
 no oil or water on the socket or mooring rope before pouring 
 (the alloy. 
 
 The length of the mooring rope for buoyant mines No. 32 
 equals the depth at low tide, less 15 feet. This allows 5 feet 
 
SUBMARINE MINING. 47 
 
 for the length of the mine, anchor, and shackles, and 10 feet 
 for submergence. When thimbles and clips are used the 
 mooring rope is cut 3 feet longer and is bent back a foot and 
 a half at each end for the thimbles and clips. 
 
 For the larger mine cases, an additional allowance must 
 be made for the length of the cylindrical part of the case. 
 
 Each mooring rope is carefully tagged at each end with 
 the number of the corresponding mine. 
 
CHAPTER V. 
 
 ASSEMBLING AND PLANTING MINES. 
 
 NOTE. The instructions to be observed by the master of a mine 
 planter in marking out a mine field and in planting mines are to be 
 found in Appendix No. 6. 
 
 The planter detail. This consists of the chief planter and 
 3 noncommissioned officers and 16 privates, distributed in 
 three details, as follows: One noncommissioned officer and 
 six privates on each side of the planter and one noncommis- 
 sioned officer and four privates aft. 
 
 Tools and supplies. The tools and supplies to be taken 
 aboard for the work described are : 
 
 On the planter. 
 
 On distribution-box boat. 
 
 In each yawl. 
 
 Alcohol. 
 
 Alcohol. 
 
 Anchor, boat. 
 
 Anchors. 
 
 Anchors, boat (2). 
 
 Anchor line. 
 
 Axe. 
 
 Axe. 
 
 Boat hook. 
 
 Boat hooks. 
 
 Boat hook. 
 
 Heaving line. 
 
 Buoy, key. 
 Buoys, mine. 
 Cable cutter. 
 
 Boat telephone with connec- 
 tors and earth plate. 
 Breaker of drinking water. 
 
 Life buoy. 
 Life preservers, 1 for each 
 man. 
 
 Cables, multiple. 
 
 Buoy. 
 
 Marline. 
 
 Cables, single conductor. 
 Cable tags. 
 Clips, cable. 
 
 Cable tags. 
 Compass, boat. 
 Distribution box. 
 
 Megaphone. 
 Oars and locks (7). 
 Sounding line. 
 
 Cotter pins. 
 Crank handle for automatic 
 
 Flags, boat (2). 
 Gasoline (tankful). 
 
 
 anchor. 
 
 Green light. 
 
 
 Dry cells. 
 
 Hammers. 
 
 
 Grappling hooks. 
 
 Heaving lines. 
 
 
 Hammers. 
 
 Kerosene. 
 
 
 Heaving lines. 
 
 Knives, submarine-mine. 
 
 
 Kerosene. 
 
 Lamps, alcohol (2). 
 
 
 Knives, submarine-mine. 
 
 Lashings. 
 
 
 Lamps, alcohol (2). 
 
 Life buoys (2). 
 
 
 Life buoys (3). 
 
 Life preservers, one for each 
 
 
 Marline. 
 
 man. 
 
 
 Marlinespikes. 
 
 Marline. 
 
 
 Matches. 
 
 Marlinespike. 
 
 
 Megaphone. 
 
 Matches. 
 
 
 Mines. 
 
 Megaphone. 
 
 
 Monkey wrenches. 
 Nuts. 
 
 Monkey wrenches. 
 Notebook and pencil. 
 
 
 Ropes, mooring. 
 
 Red light. 
 
 
 Rcxpcs r&ising. 
 
 Rope, raising. 
 
 
 Shackles, anchor. 
 Shackles, mine. 
 
 Ropes, buoy (2). 
 Shackles. 
 
 
 Shoes, mine-cap. 
 
 Tools and materials to make 
 
 
 Sister hooks. 
 Spring balance. 
 
 Turk's-heads and joints. 
 Waste. 
 
 
 Stamping outfit. 
 
 White lights (2). 
 
 
 Tools and materials necessary 
 
 
 
 to make Turk's-heads and 
 
 
 
 joints. 
 
 
 
 Voltmeter. 
 
 
 
 Washers. 
 
 
 ** 
 
 Waste. 
 
 
 
 Wire, soft-drawn copper. 
 
 
 
 Wrench, socket, for automatic 
 
 
 
 anchor. 
 
 
 
SUBMARINE MINING. 
 
 49 
 
 Preparing mine cables. A reel of single-conductor cable 
 is taken from the tank and placed on a cable-reel frame. A 
 piece 20 feet long is cut off the end to eliminate the part 
 which was above water during storage. The cable for the 
 mines is now unreeled, cut to the following lengths plus twice 
 the approximate depth of the water, and each end carefully 
 tagged with the number of the corresponding mine. A 
 Turk's-head is made on each end. 
 
 No. 11 
 
 No. 12 
 
 No. 13 
 
 No. 14 
 
 No. 15 
 
 No. 16 
 
 No. 17_ 1,025 
 
 No. 18 1, 225 
 
 No. 19 1,425 
 
 Feet. 
 425 
 475 
 525 
 625 
 725 
 825 
 
 Feet. 
 
 No. 1 1,425 
 
 No. 2 1,225 
 
 No. 3 1,025 
 
 No. 4 825 
 
 No. 5 725 
 
 No. 6 625 
 
 No. 7 525 
 
 No. 8 475 
 
 No. 9 425 
 
 No. 10 375 
 
 The mine cables are coiled in figure 8's. In order to secure 
 uniformity in the size of the coils, they may be coiled on a 
 rack (improvised at the post). This rack is made of one 
 12-foot length of 4 by 6-inch scantling, crossed at right angles 
 by two 6-foot lengths (4 by 6 inch) placed 5 feet apart. 
 Four 1-inch holes are bored through each of the timbers 
 about 2 feet from each of the crossings, and a 2- foot length 
 of gas pipe is inserted in each hole. These pipes make the 
 form on which the coils are made. 
 
 A cable must be coiled for planting so that both ends are 
 free, one to be passed to the distribution-box boat, the other to 
 be carried forward on the planter and attached to the mine. 
 This is accomplished by starting the coil about 135 feet from 
 the mine-cap end, the approximate length required to run for- 
 ward when using a mine planter. The cable is coiled on the 
 form, spreading out the laps at the center to reduce the 
 height at that point, until the entire length is coiled. The 
 outer loops and the center of the figure 8 coil are lashed, 
 leaving the ends sufficiently long to lash the part of the cable 
 
 11003 12 5 
 
50 SUBMARINE MINING. 
 
 remaining uncoiled. The mine-cap end of the cable is then 
 coiled on top of the coil and lashed with the ends of the rope. 
 Single-conductor cables when coiled should be tested for 
 continuity of circuit and grounds before being placed aboard 
 the planter. 
 
 For continuity of circuit the two ends of the cable are con- 
 nected to a battery and voltmeter in series. If the cable has 
 no break, the reading of the voltmeter should show approxi- 
 mately the same deflection as when the battery circuit and 
 voltmeter alone are in circuit. 
 
 To test for a ground the cable is submerged in a testing 
 tank, leaving both ends out. It is advisable, when practi- 
 cable, to extend a lead from one of the operating boards of 
 the mining casemate to the cable tank. One end of the cable 
 to be tested is connected to this lead and the test made as 
 prescribed for " insulation test " on page 44. The condition 
 of a multiple-conductor cable can be quickly determined by 
 this arrangement. If the above method is not practicable, a 
 dry-cell battery with a mil-ammeter and protective lamp may 
 be installed at the cable tank ; or, in place of the mil-ammeter 
 and lamp, a voltmeter placed in series with the battery and 
 cable may be used, the resistance being obtained by the volt- 
 meter method. One side of the battery should be grounded 
 by touching the cable armor or by using an earth plate. In 
 actual service, cable which tests under 1 megohm should not 
 be used ; for practice, cable under 10,000 ohms should not be 
 used. If post power is used as a source of energy for testing, 
 the system should be free from grounds. Care should be 
 taken to have the cable ends and battery leads free from 
 grounds and dry, 
 
 Cables are raised and lowered into the tank by means of a 
 cable yoke, which consists of an 11-foot length of 4 by 6 
 inch scantling, with three hooks on the lower side and a 
 ring on the upper side at the center for hoisting. The lower 
 hooks, which are secured to the scantling by a bolt and ring, 
 hook into the lashing on the cable. Washers are placed 
 under the bolt heads to prevent their slipping through the 
 holes. 
 
SUBMARINE MINING. 51 
 
 Swinging or traveling cranes with triplex blocks are used 
 for lowering and raising cable and yoke. 
 
 The coils of single-conductor cable are carried aboard the 
 planter, to the aft deck, by the cable detail, or they may be 
 lowered onto the deck by means of the cable yoke and a der- 
 rick on the wharf. The cable for mine No. 1 is placed on 
 the starboard side of the aft deck and its mine-cap end is 
 carried forward on the cable racks close to the mines. The 
 other cables, Nos. 2 to 9, inclusive, are placed in succession 
 on the starboard side in the same manner. The cables, Nos. 
 19 to 10 are placed in succession on the port side, with No. 19 
 at the bottom. The coils on each slide are placed on top of 
 each other. The cable should be removed from the racks 
 when its corresponding mine is being prepared for planting. 
 
 At the same time the other apparatus and appliances are 
 carried aboard and placed forward, the proper supply on 
 each side. The anchors are placed as convenient to the 
 forward davits as possible. 
 
 Finally, the loaded mines are put aboard. If they contain 
 dynamite they should be protected from the direct rays of 
 the sun by being covered with a paulin. 
 
 Preparing mines for planting. The detail on each side of 
 the planter prepares a mine on its own side. The loading 
 wire from the mine is cust to the proper length, a water-tight 
 joint is made with the single conductor of the corresponding 
 cable, and the Turk's-head is clamped in place, care being 
 exercised that no part of the leading-in wire is caught under 
 the clamp. The cable is lashed with soft-drawn copper wire 
 or secured by clips to the bails just above the ring. 
 
 The proper mooring rope is now shackled at one end to 
 an anchor, at the other end to the mine, and is lashed to the 
 mine cable with soft- drawn copper wire at every 5 feet. If 
 automatic anchors be used, the mooring rope is shackled to 
 the mine after the anchor and mine are swung outboard ; the 
 lashing of the cable to the mooring rope is omitted. 
 
 A rope for raising the mine is cut to the length of 80 feet 
 plus the depth of water. One end is attached to the anchor 
 by an anchor knot or bowline, the other to the mine cable by 
 
52 SUBMARINE MINING. 
 
 two half hitches and a seizing of soft-drawn copper wire. 
 It should not be secured at other points. 
 
 The mine buoys have attached to them 60 feet of -inch 
 rope, which is marked at every 5 feet. The free end is 
 slipped through the maneuvering ring of the mine and tied 
 to the buoy. 
 
 When planting mines for practice, marline may be used 
 to seize the raising rope to the cable and to lash the cable to 
 the bail and mooring rope. 
 
 A mousing must be put around the upper hook of the 
 differential block to prevent the block from jumping off the 
 hook when the mine or anchor is tripped. The tripping 
 hook of the differential block on the forward davit is attached 
 to the anchor and it is hoisted and swung outboard clear of 
 the rail. The mine is similarly slung from the after davit by 
 its maneuvering ring or by a rope sling through the latter. 
 Both mine and anchor are lowered as close to the water as 
 conditions will permit. A heaving line is bent onto the free 
 end of the mine cable, generally by means of a clove hitch 
 and two half hitches. 
 
 The aft detail now removes or cuts the rope lashings of the 
 coil of the corresponding mine cable. A detail sees that the 
 cable and raising rope are held on the gunwale ready for 
 planting. These should not be allowed to trail in the water. 
 A man 'stands near the mine davit ready to throw the mine 
 buoy clear of the planter when the mine is tripped. (Fig. 13 
 shows the mine and anchor slung for planting and fig. 14 
 shows the relative position of the various parts in the water. 
 In these figures the cable should be shown as lashed to the 
 mooring rope.) 
 
 The distribution-box boat should precede the planter to the 
 mine field. The distribution-box buoy, to which the anchor 
 rope is fastened by a bowline, to the bight of which the rais- 
 ing rope is secured, is taken aboard at !the bow, if the tide is 
 coming in toward the box, and the anchor rope is made fast. 
 The distribution box is then raised by its raising rope and 
 secured in the stern. The boat is thus anchored fore and aft, 
 perpendicular to the line of mines, with its bow pointed 
 toward the position of the center mine of the group. If the 
 tide is running out from the box, the buoy should be taken 
 
SUBMARINE MINING. 53 
 
 in at the stern, the boat being held in position by the raising 
 rope of the distribution box and then by the multiple cable. 
 The anchor rope is finally made fast in the bow. During the 
 planting of mines a man should always stand ready to 
 slacken away on the anchor rope if necessary. 
 
 If the buoy for the distribution box is not in place, the 
 cable must be underrun, either from shore or from a buoy 
 planted for this purpose. This is done preferably with a 
 yawl. The cable is raised, taken aboard, and placed over a 
 roller or rowlock in the stern. The cable is then pulled in 
 over the stern and lowered over a roller or rowlock in the 
 bow. If the planter is to underrun cable, a cathead is put 
 in place and a snatch block is lowered by a raising rope 
 secured to a hoisting windlass. The cable is placed in the 
 snatch block and the planter moves forward slowly. When 
 it is desired to transfer the cable to a small boat the snatch 
 block is lowered into the boat and the cable removed. 
 
 After the distribution-box boat has secured the box in 
 position, the lid is removed and the cable is tested as pre- 
 scribed on page 44. A signal is then raised to indicate to 
 the planter that the distribution-box boat is ready for the 
 planting of mines. 
 
 Planting the mines. If there be a strong tide, the mines 
 should, if possible, be planted at such time that the planter, 
 in going out toward the line of mines, moves against the tide. 
 
 The planter moves but and passes close to the distribution- 
 box boat, with the latter to port. As it passes slowly by. a 
 heaving line is thrown by a man forward of the beam to the 
 distribution-box boat, whose party immediately hauls in the 
 mine cable, bends on another heaving line, and lashes the 
 cable to the boat. It is desirable to have a second heaving 
 line ready in case the first one fails. If the water be rough 
 the cable end is passed to the boat by a launch. 
 
 The planter moves forward to the position to be occupied 
 by mine No. 10. If automatic anchors are used, the distance 
 weight is lowered at the command " Lower weight," given 
 after the cable is secured in the distribution-box boat. As 
 the planter approaches this position the command " Get 
 
54 SUBMAKINE MINING. 
 
 ready " is given. As the forward davit comes abreast of the 
 position of No. 10 mine, the officer in charge of the planting 
 commands " Let go " ; the tripping hook of the mine is re- 
 leased first and that of the anchor immediately thereafter. 
 The mine buoy, cable, and raising rope are then thrown 
 overboard. 
 
 (Caution. The men operating the tripping hooks must 
 be very careful that they stand back of all cable and rope, so 
 that they may not be caught. All others must stand clear.) 
 
 The planter turns so that the stern will be thrown away 
 from the planted mine. When the stern is clear of the mine 
 buoy "All clear" is signaled from the stern. 
 
 The planter then executes a sweeping circle to starboard, 
 passes to the rear, and comes up with the distribution-box 
 boat to starboard. As it moves by, the free end of mine 
 cable No. 9 is passed to the boat and secured as before. The 
 planter moves ahead to a point 100 feet to the left of mine 
 No. 10, and as it crosses the line, plants mine No. 9, swings 
 off to port, circles and comes up from the rear with the dis- 
 tribution box to port, and so on alternately until all the 
 mines are planted. 
 
 As soon as a mine is dropped the detail for that side of 
 the planter prepares another for planting. There is ample 
 time to do this while the vessel is turning and planting the 
 other mine. 
 
 Two small boats, one on each side of the line, work as fol- 
 lows: As soon as a mine is dropped the boat on the corre- 
 sponding side moves to it, picks up the buoy, pulls the rope 
 taut, notes the submergence of the mine, transmits the data 
 to the planter, and holds up an oar or a flag in prolongation 
 of the buoy rope. The observers at the ends of the base line 
 take observations on this marker and are thus able to plot 
 the position of the mine accurately. This process is repeated 
 for each mine. 
 
 These boats also serve as guides to the planter in dropping 
 mines by holding on to their buoys until the adjacent mines 
 are planted. With automatic anchors the line may not be 
 marked otherwise than in this manner. 
 
SUBMARINE MINING. 55 
 
 After the mine is dropped, the members of the distribution- 
 box boat party remove the lashing from the cable, insert the 
 Turk's- head in the proper slot, make a temporary joint be- 
 tween it and the corresponding conductor of the multiple 
 cable, and telephone to the casemate operator. The latter 
 opens all the power switches on the corresponding operating 
 board, closes switch No. 7 up (this throws D. C. power on 
 the mil-ammeter lead) , and then plugs in on the upper jaw of 
 the power switch of the mine under test. If the D. C. volt- 
 age be 110, the mil- ammeter should read about 40 mil- 
 amperes ; if the voltage be 80, the reading should be about 30. 
 If this test be satisfactory, the joint is made permanent. 
 
 For the last mine the telephones are removed from the 
 corresponding conductor, a temporary joint is made in the 
 boat, and the test made as above. By arrangement with the 
 casemate operator the mine is left on two minutes for test. 
 At the end of this time the joint is opened and the telephones 
 put back. If the casemate operator reports the test satisfac- 
 tory, the telephones are again removed and a permanent 
 joint is made. 
 
 When the last joint has been made, the distribution box is 
 closed and the raising rope fastened to its lid. The box is 
 then lowered. This is done by the distribution-box boat if 
 it is provided with the necessary davit and power, otherwise 
 it is done by the planter. Generally the anchor rope is made 
 fast to a buoy by a bowline, and the raising rope of the dis- 
 tribution box is secured to the bight of the bowline. 
 
 After the distribution box is lowered all buoys are re- 
 moved except that for the box, and such others as it may be 
 desired to place for marking the ends of lines. The mark- 
 ing boats may remove the mine buoys as they work, provided 
 they are notified from the mine commander's station that 
 proper observations for plotting have been obtained. Such 
 notification is usually sent by telephone to the distribution- 
 box boat. 
 
 In time of war decoy buoys judiciously placed would be 
 very useful in deceiving the enemy. 
 
CHAPTER VI. 
 TESTS OF MINES AND APPARATUS. 
 
 After the mines have been planted the following tests are 
 made daily, or more frequently if need be, the results being 
 recorded carefully on the form given at the end of the 
 chapter. (Note : This applies also to such test mines as may 
 be kept planted for purposes of observation and instruction. ) 
 
 Caution. If A. C. power be supplied from the casemate 
 motor-generator, there is no possibility of accidental firing 
 of mines if the motor-generator is not running; and when 
 it is running the chance is remote, since it would require the 
 committing of three blunders. However, the following pre- 
 cautions must be enforced rigidly: 
 
 (a) Never start the motor- generator during the planting 
 of mines nor when any friendly vessels are in the neighbor- 
 hood of the mine field. 
 
 (b) Before starting the motor-generator for testing it, see 
 that all automatic switches are up, all firing switches open, 
 and the A. G . operating switch (No. 8 of the power panel} 
 open. 
 
 1. Test of the D. C. voltage. Plug in at the proper recep- 
 tacle and read the voltmeter. 
 
 2. Test of the A. C. voltage. Caution. First see that all 
 automatic switches are up, that the firing switches are open, 
 and that the A. C. operating switch No. 8 is open. 
 
 Close switch No. 4 up; close starting switch of moitor- 
 generator, and when the latter has attained its full speed 
 close switch No. 9 up ; plug in at the proper receptacle, and 
 read the voltmeter. When the source of power is the storage 
 battery, the battery rheostat should be adjusted until the A. C. 
 voltage is 500 or above; when the casemate generator is used, 
 its field rheostat should be adjusted for the same purpose. 
 56 
 
SUBMARINE MINING. 57 
 
 3. Test of the mines. Leakage in mine circuits will be indi- 
 cated automatically by an increased brightness of the green 
 lamp on the signal block; an excessive leakage in any mine 
 circuit may cause the automatic switch to trip. 
 
 However, each mine should be tested separately, as fol- 
 lows: 
 
 With the D. C. on the D. C. busses of the power panel, 
 close switch 7 up, open the power switch on the mine block 
 of the mine circuit to be tested, and put the M-AM " plug " 
 on the upper point of the power switch. If the automatic 
 switch falls, adjust the solenoid or hold the switch up while 
 testing the circuit, otherwise the reading obtained will be 
 that of the red lamp and bell circuit. These operations 
 put the mil-ammeter and its protective lamp in series with 
 the mine circuit. 
 
 The circuit is as follows : From the negative D. C. bus on 
 the power panel, to switch 7 closed up, through the mil- 
 ammeter and its protective lamp, to the terminal bar, to the 
 M-AM lead, to the plug, to the upper point of the power 
 switch P, through the solenoid, to the middle of the testing 
 switch T, to the upper point of same, to the upper point of 
 the automatic switch, to the middle of same, to the mine 
 switch, through same, to the terminal bar, through the 19- 
 conductor and the single-conductor cables, to the mine trans- 
 former primary, to the mine case, to ground, to the D. C. 
 "earth" terminal on the power panel, to switch 7, and to 
 the positive D. C. bus on the power panel. 
 
 With from 80 to 110 volts these readings should normally 
 be between 30 and 40 mil- amperes. A mine may be fired if 
 the reading with 80 volts is between 14 and 120 mil-amperes. 
 These limits increase with the testing voltage. If the mine 
 tests within the firing limits, the solenoid should be adjusted 
 if the current is above its normal setting (0.075 amperes). 
 If the test indicates that the mine can not be fired, the mine 
 switch should be opened. 
 
 4. Test of the automatic switch, red lamp, and bell. Throw 
 the D. C. power on the busses of the operating board by 
 closing switch 3 up. Open the bell switch. Next close the 
 testing switch down on the mine block under test. The red 
 
58 SUBMARINE MINING. 
 
 lamp should glow and the corresponding automatic switch 
 trip. (For circuit see fig. 18.) Now close the bell switch, 
 throwing the bell in parallel with the red lamp; the bell 
 should ring. Next open the bell switch and repeat the test 
 for each mine block in turn. 
 
 5. Test of the alternating circuit. This circuit is tested with 
 D. C., as follows: Connect the A. C. and D. C. jaws on the 
 master block witlt a jumper, open the power switches, close 
 switches 3, 8, and 9 up on the power panel. The green and 
 white lamps of the operating board under test should glow. 
 A break or an excessive resistance in the casemate grounds, 
 or elsewhere in the circuit, will be indicated by the lamps not 
 glowing, or glowing dimly. 
 
 The circuit is as follows: From the negative D. C. bus on 
 the power panel, to switch 3, to the " operating board " ter- 
 minal, to the D. C. lead, to the D. C. post on the signal block, 
 through the green lamp, to the D. C. jaw on the master 
 block, through the jumper, to the A. C. jaw on the master 
 block, through the white lamp and resistance in parallel, 
 to the A. C. post on the signal block, to the A. C. lead, to 
 the A. C. " operating board " terminal, to switch 8, to the 
 A. C. bus, to switch 9, to the casemate transformer second- 
 ary, back to switch 9, to the other A. C. bus, back to switch 
 8, to the A. C. earth, through ground, to the D. C. earth, to 
 switch 3, and to the positive D. C. bus on the power panel. 
 With this circuit on, remove the 90-ohm resistance in parallel 
 with the white lamp ; the white lamp should glow more 
 brightly, indicating continuity of circuit through the resist- 
 ance as well as the white lamp. 
 
 It will be observed that the above test is for only a part 
 of the A. C. circuit. To test the firing switch and the lower 
 contact of the automatic switch, open switches 3, 8, and 9, 
 close 7 up, remove the jumper, put the M-AM " plug " on 
 the A. C. jaw on the master block, close the firing switch, and 
 trip in turn each automatic switch by raising the corre- 
 sponding knob on the solenoid and observe the reading of 
 the mil-ammeter. Close each automatic switch up before 
 tripping the next one. 
 
SUBMAKINE MINING. 59 
 
 The mil- ammeter reading should be from 30 to 40 mil- 
 amperes, indicating a circuit through the firing switch and 
 the automatic switch. The circuit is as follows: From the 
 negative D. C. bus on the power panel, to switch 7 closed up, 
 through the mil- ammeter and its protective lamp, to the 
 operating board terminal, to the M-AM lead, to the " plug," 
 to the A. C. jaw on the master block, through the firing 
 switch F. S., to the A. C. bus on the operating board, to the 
 lower point of the automatic switch which was tripped, to 
 the middle of same, to the mine switch, through the same, 
 to the terminal bar, through the 19-conductor and the single- 
 conductor cables, to the mine transformer primary, to the 
 mine case, to ground, to the D. C. " earth " post on the power 
 panel, to switch 7, to the positive D. C. bus on the power 
 panel; 
 
 6. Test of the delivery of the A. C. power to the operating 
 board. See that all the automatic switches of the operating 
 boards are up and all the firing switches of the master blocks 
 open. Close switches 4 and 9 up (or down) and 8 down ; close 
 the testing switch T. S. on the master block. The white 
 lamp should glow and the A. C. bus-bar voltage should drop 
 appreciably. 
 
 The circuit is as follows : From the A. C. bus on the power 
 panel, to the lower right terminal of switch 8, to the " oper- 
 ating board " terminal, to the A. C. lead, to the A. C. post on 
 the signal block, to the white lamp and the resistance in par- 
 allel, to the A. C. jaw on the master block, to the testing 
 switch T. S., to the " earth " post on the signal block, to 
 the earth lead, to the D. C. earth, through earth, to the A. C. 
 earth terminal on the power panel, through the choke coil, 
 to switch 8, to the other A. C. bus on the power panel. 
 
 In this test it is imperative to see that all the automatic 
 switches are up and all the firing switches are open. 
 
 7. Test of the power. Insert two fuses in multiple across 
 the fuse leads from the power panel. Put the fuses in a place 
 prepared for the purpose outside of the casemate, so that 
 there will be no danger from flying fragments. With all the 
 switches on the power panel open, all the automatic switches 
 
60 SUBMARINE MINING. 
 
 up, and the firing switches on the master blocks open, ener- 
 gize the D. C. busses of the power panel, close switch No. 4 
 up (or down), and close the starting switch; close switch 
 No. 9 up (or down) ; close switch No. 12 up (which connects 
 the mine transformer secondary to the fuses) ; and, finally, 
 close switch No. 11 up (which throws the A. C. power on the 
 mine transformer primary) . The fuses should explode. 
 
 If fuses are not available for this test, a low-voltage lamp 
 or a short piece of fine wire may be heated to incandescence. 
 
 8. Test of grounds. (a) " Separate " grounds shall be made 
 for the A. C. power and the D. C. power on the power panel. 
 The word " separate " as here used means actual connection 
 to earth without metallic contact of the earth leads. A 
 convenient method of making a ground is to connect to the 
 armor of a cable running to salt water, a bond being made 
 in case the armor of the cable in the casemate does not reach 
 water before a joint is made. If a cable armor is used 
 for one ground, the other ground lead must go to earth with- 
 out contact with that armor. This may be accomplished by 
 using the conductors of a cable, the ends of which are 
 grounded to an earth plate in 'salt water. 
 
 (6) Neither of the grounds made should have more than 
 10 ohms resistance. To verify this, tests should be made 
 as follows : 
 
 Close the double circuit breaker ; close switch 7 up and plug 
 the extension cord of the mil-ammeter lead of the power 
 panel on the upper left-hand terminal of switch 8, the mil- 
 ammeter extension cords for the operating boards being dis- 
 connected. 
 
 Ascertain the voltage across the mil- ammeter and lamp, 
 and across the bus bars. Read the mil- ammeter. 
 
 From these readings the combined resistance of the grounds 
 can be determined. 
 
 A table or chart may be prepared giving the resistances for 
 various testing voltages and mil-ammeter readings. 
 
SUBMAKINE MINING. 
 
 Form for record -of tests, Group No. 
 
 61 
 
 
 I 
 
 
 
 
 
 
 
 
 
 No. 
 
 
 
 5 
 
 " : 
 
 |l 
 Z* 
 
 J? 
 
 C. on A. C. 
 . S. closed. 
 
 S J? 
 
 i! 
 
 M 
 
 D. C. on A. C. 
 
 F. S. closed. 
 
 f 
 
 Auto, switch 
 lamp & bell. 
 
 D. C. on A. C. 
 F. S. closed. 
 
 a, 
 = 
 
 - 
 
 Auto, switch 
 lamp & bell. 
 
 D. O. on A. C. 
 F. S. closed. 
 
 Mil. amp. 
 
 Auto, switch 
 lamp & bell. 
 
 - _ 
 =1 
 
 s 
 
 m 
 
 9 
 
 Auto, switch 
 lamp & bell. 
 
 _' c 
 
 Re- 
 marks. 
 
 
 
 * <- 
 
 
 s~< 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 2 
 3 
 4 
 
 5 
 
 C 
 
 7 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 - 
 
 
 
 
 
 ~_ 
 ~ 
 
 
 
 
 \ 
 
 
 
 E 
 
 ; 
 
 
 
 
 
 ; 
 
 = 
 
 
 
 - 
 
 2 
 
 
 
 ; 
 
 
 
 -: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 8 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 9 
 10 
 11 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 ~ 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 12 
 13 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 14 
 
 15 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 16 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 - 
 
 
 
 17 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 18 
 19 
 
 - 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 
 
 - 
 
 
 
 D. C. on A. C. 
 F. S. open. 
 
 
 
 
 
 
 
 
 
 D. C. volts .... 
 
 
 
 
 
 
 
 
 
 
 A. C. volts 
 
 
 
 
 
 
 
 
 Fuses, fired 
 
 
 
 
 
 
 
 
 
 Delivery of A. 
 C. power to 
 the Op. Bd. 
 
 
 
 
 
 
 
 
 
 
 Grounds. 
 
 
 
 
 
 
 
 
 Remarks. 
 
 
 
 
 
 
 
 
 
CHAPTER VII. 
 TAKING UP MINES. 
 
 Mines should be raised in the reverse order from that in 
 which they were planted if the conditions of wind and tide 
 are favorable. With a cross tide or a strong cross wind, the 
 mines should be taken up in regular order from one side so 
 that the planter will not drift onto the mine field. 
 
 A yawl or launch takes position at the outer mine on each 
 side. The mine-buoy rope is hauled up taut in order to 
 locate the exact position of the mine. The boat holds fast 
 until directed from the planter to let go. While the anchor 
 and mine are being taken aboard the planter, the boat 
 remains off the bow to render assistance if necessary. 
 
 The distribution box is raised by underrunning the mul- 
 tiple cable, or by means of its raising rope if the buoy has 
 not been removed. The box is taken aboard the distribution- 
 box boat, the lid is removed, and the mine cables, in turn, 
 disconnected from the multiple cable. The planter passes 
 close to the distribution-box boat. A heaving line which has 
 been made fast to the outer mine cable is thrown to the bow 
 of the planter. If this should fail, a man throws a heaving 
 line from the bow of the planter. If the conditions be unfa- 
 vorable for passing a heaving line, a launch may carry the 
 line to the planter. The heaving line attached to the cable is 
 hauled aboard and the cable placed over the cathead. The 
 planter then proceeds to underrun the cable. If the water 
 be shallow, the cable is carried through a snatchblock to the 
 aft deck and coiled, or it may be carried to a cable reel for- 
 ward. If the water be deep, or the cable can not be raised 
 easily by hand, it is carried through a snatchblock to the 
 drum of a hoisting windlass and coiled as before mentioned. 
 62 
 
SUBMARINE MINING. 63 
 
 (If placed on a cable reel, the ends should be insulated and 
 tagged. Mine cables Nos. 1 to 9 should be placed on one reel 
 and Nos. 10 to 19 on another, both reels being carefully 
 marked.) When the raising rope is reached, it is carried 
 with the cable over the cathead. The bight of the rope is 
 hauled in quickly, carried through a snatchblock, and a few 
 turns taken on the drum of a hoisting windlass. The rope is 
 untied from the cable as soon as possible. If there be danger 
 of losing the rope, it should be made fast at once. The 
 anchor is raised until within a few feet of the cathead. It 
 is lifted aboard by means of the boom, or by the differential 
 block on the anchor davit. 
 
 At the same time a man is sent over the side of the planter 
 near the mine davit (a rope ladder may be used) to secure 
 the hook of the differential block in the sling attached to the 
 maneuvering ring of the mine when it comes to the surface. 
 To bring the mine to the proper place to accomplish this, a 
 man should be ready to secure the mine-buoy rope with a 
 boathook; other men should be ready to pull the mine for- 
 ward, if necessary, by means of the cable. The mine is raised 
 by the differential block of the mine davit. It may be raised 
 by the boom and fall ; or by means of a tackle secured to the 
 mine davit, the end of the rope running through a snatch- 
 block to the drum of a windlass. The distance weight of the 
 automatic anchor may be raised by the fall of the boom, or 
 by an improvised tackle. An eye should be made in the 
 distance rope for this purpose. 
 
 If the end of the cable is lost, the work may proceed as 
 follows: The planter moves out to the mine if its buoy is 
 still in place. A sling made of raising rope may be thrown 
 over the mine, or two raising ropes are tied together and 
 one end is passed to a launch which moves around the mine 
 and brings the end, back to the planter. Both ends are 
 placed over the cathead, through a snatchblock, and around 
 the drum of a hoisting windlass. The mine is hoisted, bail 
 up, until near the cathead. It can then be transferred to the 
 anchor davit. The mine cable is pulled in until the raising 
 rope is reached. The work then proceeds as before. If the 
 11003 12 6 
 
64 SUBMARINE MINING. 
 
 mine buoy has been removed, a yawl may drag for the cable 
 with a grappling iron. If the raising rope should break or 
 be lost, the mine may be raised as mentioned above, except 
 that the mine must be transferred to the fall of the boom and 
 the anchor raised by means of its mooring rope, or the mine 
 may be transferred to the anchor davit, as before, and a rais- 
 ing rope made fast to the mooring rope of the anchor and 
 carried over the cathead, through a snatchblock, to a hoisting 
 windlass. The mine, as soon as the strain is taken up by the 
 raising rope, is unshackled. The anchor is then taken aboard 
 in the usual manner. 
 
 As soon as the mines are taken aboard they are discon- 
 nected, the ropes are coiled, and all materiel placed so as not 
 to interfere with subsequent work. As soon as the materiel 
 is unloaded on the wharf it should be cleaned thoroughly and 
 stored. 
 
 If the multiple cable is to be left down, the ends of the 
 conductors are insulated, the lid replaced, and the box low- 
 ered by means of a raising rope, the end of which is made 
 fast to the bight of the bowline of the anchor rope. 
 
 If the multiple cable is to be taken up, the end is passed to 
 the planter, run through a large snatchblock on the bow, and 
 coiled on a cable reel as it is raised. Whenever a multiple 
 cable is coiled on a reel it should be secured so that both ends 
 will be available for test when the cable is stored. 
 
 Unloading mines. Should any of the mines be loaded with 
 dynamite the utmost care must be exercised in unloading 
 them. (See p. 76.) Some contrivance must be rigged up 
 so that the first few turns of the compound plug may be 
 accomplished by the operator at a distance, as there is great 
 liability of explosion, due to leakage of nitroglycerin into 
 the screw threads. After the compound plug is removed the 
 precautions to be observed are given in Appendix No. 1. 
 
 Should the mine be loaded with guncotton or trotol, no 
 danger is to be apprehended in unloading; the usual pre- 
 cautions in handling high explosives must, of course, be 
 observed. 
 
CHAPTER VIII. 
 THE MINE COMMAND. 
 
 A mine command consists of the mine groups and rapid- 
 fire batteries specifically assigned for their protection, which 
 are controlled by a single individual. 
 
 The mine commander is in direct command of the ele- 
 ments of the mine defense during drill and action. His 
 station is at the mine primary, which is connected by tele- 
 phone to the battle commander's station. He bears the same 
 relation to the battle commander as do the fire commanders, 
 and his duties are similar to theirs. 
 
 The mine commander is responsible that the property 
 officer requests for all materiel necessary to carry out the 
 approved scheme for mining the harbor; he is responsible, 
 further, that the property officer keeps this materiel in proper 
 condition for immediate service. 
 
 The senior company officer of the mine command is the 
 property officer and obtains from the district artillery engi- 
 neer all necessary materiel for the mine defense. He has 
 direct charge of the storeroom, cable tanks, loading room, 
 wharves, boats, boathouses, and mining casemate. The per- 
 sonnel of the mine companies are subject to his orders for 
 service in connection with caring for and maintaining this 
 materiel. 
 
 The officers of the companies of the mine command will 
 be assigned by the mine commander in accordance with 
 their special fitness. 
 
 The enlisted personnel of mine companies will be divided 
 into sections, detachments, and details, as follows: 
 
 (a) Fire-control and power section. 
 
 (b) Planting and loading section. 
 
 (c) Gun and ammunition sections. 
 
 (d) Reserve section. 
 
 65 
 
66 SUBMARINE MINING. 
 
 These will be subdivided as follows : 
 
 (a) Fire-control and power section: 
 
 1. Observing detachment 
 
 a. W detail. 
 6. M" detail. 
 c. M'" detail. 
 
 2. Plotting detachment 
 
 a. Plotting-board detail. 
 &. Communication detail. 
 
 3. Power detachment 
 
 a. Casemate detail. 
 6. Searchlight detail. 
 (I) Planting and loading section: 
 
 1. Planting detachment 
 
 a. Planter detail. 
 
 &. Small-boat details. 
 
 2. Loading detachment 
 
 a. Loading-room detail. 
 6. Explosive detail, 
 c. Cable detail. 
 
 (c) Gun and ammunition section: 
 
 a. Gun details. 
 
 6. Projectile detail. 
 
 c. Powder detail. 
 
 ( d ) Reserve section : As required. 
 
 In each company assigned to the mine defense, a perma- 
 nent manning table will be made out and always kept up to 
 date. A copy of this manning table will be posted in the 
 mine commander's station. In addition, a copy of such por- 
 tion of this table as pertains to any particular station will 
 be posted therein. 
 
 Plotting board. The plotting board differs from that used 
 for guns in that it requires no gun arm and corresponding 
 attachments. Furthermore, since the distance at which mines 
 are planted will in general be small, the board, without any 
 change in size, may be used with a much larger scale, say, 150 
 yards or even 100 yards to the inch, and the arms graduated 
 accordingly. 
 
 The stations are manned during the planting of mines and 
 the location of distribution boxes, as well as during opera- 
 tions. 
 

 105- -105 
 
 120 120 
 
 125 125 
 
 ISO 150 
 
 155 155 
 
 I60-M60 
 165 
 ITO-f- ITO 
 175 ITS 
 
 FIG. 15. PREDICTION RULER. 
 
SUBMARINE MINING. 67 
 
 For planting buoys signals may be made from the pri- 
 mary, from the secondary, or from both, as conditions war- 
 rant. 
 
 Observations are taken on each mine as planted, the data 
 are recorded, and the position of each mine is plotted. 
 
 During operations vessels may be tracked by the vertical 
 or by the horizontal method of position finding. If by the 
 former, either the command " Fire " may be given when 
 the vessel is on the cross wires of the instrument set at the 
 range and azimuth of a mine, or the time from any point to 
 the instant of passing over a mine may be found by means 
 of the prediction ruler (see below) and the command " Fire " 
 be given at the proper instant, as indicated by the stop 
 watch. For the horizontal base system the latter method 
 must be used. 
 
 Prediction ruler (fig. 15). This is a 10-inch white celluloid 
 slide rule with a beveled edge. The slide is graduated in 
 " Yards in 15 seconds," and on the left and right of the run- 
 way, respectively : are a " Fire at time " and a " Yards to 
 mine " scales. The beveled edge is graduated from the cen- 
 ter outward in both directions with " " in the center of the 
 scale and "500" at either end. Each 50 and 100 has its 
 value engraved on the scale. 
 
 Method of using. Plot the position of the target for a 15- 
 second interval. With the beveled edge find the distance the 
 target has passed over during the interval; and also deter- 
 mine the distance from the last plotted position to the mine. 
 Move the slide until the graduation corresponding to the 
 " Yards in 15 seconds " is opposite the graduation corre- 
 sponding to the " Yards to mine," and read the " Fire at 
 time " scale opposite the arrow on the slide. The reading 
 will be the number of seconds from the last plotted position 
 to the mine which the vessel is approaching. A stop watch 
 is started at the time of the last observation on the target, 
 and at the expiration of the time obtained from the " Fire 
 at time " scale the command " Fire " may be given. 
 
 Observation firing. The mine commander's station is con- 
 nected with the casemate by telephone. At the command 
 " Observation firing " sent to the casemate, the casemate oper- 
 
68 SUBMAKINE MINING. 
 
 ator will see that all automatic switches are up, and that all 
 firing switches are open. He will then close the double 
 circuit breaker, and switches 4 and 9, which will energize the 
 
 busses of the power panel. At the command " Group , 
 
 mine - ," the operator will close switches 3 and 8 on the 
 power panel, thereby putting both D. C. and A. C. power on 
 the operating boards. At the command " Ready," given 
 from the mine commander's station at the proper time, the 
 operator will stand ready to trip the corresponding auto- 
 matic switch. At the command " Fire " the automatic switch 
 will be tripped and the firing switch will be closed. Without 
 delay, after the mine is fired, the firing switch and the power 
 switch will be opened, the automatic switch closed up, and 
 the mine switch opened on the mine block. 
 
 If the mine is struck before the command " Fire " is given, 
 the automatic switch will fall, and the mine should be fired 
 by closing the firing switch unless there are positive orders 
 to the contrary. 
 
 Contact firing. For contact firing the mine system will be 
 set so thalt a signal will be sent to the casemate and the mine 
 will be fired when the latter is struck by a passing vessel. 
 This is the normal method of firing in actual service. At the 
 command " Contact firing," which may be given for all 
 groups, or certain individual ones, the casemate operator will 
 see that all automatic switches are up, power and mine 
 switches closed, and firing switches open; he will then close 
 the double circuit breaker, and switches 4, 9, 3, and 8 on the 
 power panel. This puts both D. C. and A. C. on the operat- 
 ing boards. He will then close the firing switches on all the 
 boards or on such as may have been indicated. When a mine 
 has been fired, the corresponding mine block will be cut out. 
 
 If it is desired to delay the firing of a mine after being 
 struck, the command " Delayed contact firing " is given. The 
 operations are the same as for contact firing except that the 
 firing switch is closed by the operator a short time after the 
 mine has been struck or when directed to do so. After 
 the mine has been fired the firing switch will be opened, and 
 the corresponding mine block will be cut out. 
 
APPENDIX NO. 1. 
 EXPLOSIVES. 
 
 The latest adopted explosive for submarine mines is 
 trinitrotoluol, also called trotol. The commercial names for 
 this explosive are trinol, trotyl, and triton. 
 
 Wet guncotton is used extensively for submarine mines 
 and in emergency other commercial high explosives may be 
 employed, preferably dynamite. 
 
 Trotol is a fine crystalline yellow powder, much resembling 
 brown sugar. It is manufactured by nitrating toluol. It 
 is very insensitive to shock or friction, insoluble in water, 
 very stable in storage, and very powerful when detonated. 
 Its melting point is about 81 C., its ignition point is about 
 197 C. ? its specific gravity in powdered form is about 1.55 ; 
 it has no dangerous chemical action on metals. 
 
 The priming charge is a fuse can full of crystalline trotol. 
 
 Trotol is supplied in wooden boxes doubly lined with wax 
 paper, each box containing about 50 pounds of explosive. 
 The date of receipt at the post and the name of the explosive 
 shall be painted on each box. The boxes should be stored in 
 tiers with the marked end out, the bottom tier resting on 
 skids. The explosive is not dangerous to handle, but the 
 same care should be observed in storing and handling as with 
 other high explosives. It should be stored in a perfectly dry 
 place, preferably in a magazine. If it is impracticable to 
 store in a magazine, the explosive may be stored in the driest 
 place available where it is protected thoroughly from all fire 
 risks. If from any cause the boxes of explosive are wet and 
 there is reasonable assurance that the interior has become 
 wet, a box should be selected and opened. If the interior is 
 wet, a full report of the circumstances shall be made to the 
 War Department. Boxes should be opened and the contents 
 dried in open air out of the direct rays of the sun. 
 
 69 
 
70 SUBMARINE MINING. 
 
 Trotol may be stored with wet guncotton, explosive D, and 
 dynamite. 
 
 Inspection at posts will be limited to seeing that the rules 
 for storage and care are strictly observed. Technical in- 
 spections will be made, when required, by the Ordnance 
 Department. 
 
 Wet guncotton in the form of compressed cakes is supplied 
 in boxes lined with zinc, the lid being screwed down upon a 
 rubber gasket so as to prevent the loss of water by evapora- 
 tion. Each box contains 100 pounds of dry guncotton. 
 In the lid is a small flush cap which screws down upon 
 a rubber washer and closes a tube communicating with the 
 interior of the box. Upon each box there is painted by the 
 manufacturer the net and total weights. Shipping regula- 
 tions require that guncotton should be wet with water so that 
 the water is 20 per cent of the weight of guncotton and water. 
 This is too much water for full detonation, and the gun- 
 cotton upon receipt at a post should be dried out so that the 
 weight of water is from 12 to 15 per cent of that of the dry 
 guncotton. The guncotton is dried by opening the box and 
 pyramiding the guncotton on the lid and in the box so that 
 there will be free circulation of air between the cakes. The 
 use of an electric fan in this connection will ordinarily 
 materially facilitate the operation. By weighing pilot cakes 
 it may be determined when the proper amount of water has 
 evaporated. The guncotton is then repacked, lid screwed 
 down, and the weight chalked upon the end of the box. The 
 guncotton should be placed while drying so that it is not in 
 the sunlight and should be handled with clean cotton or 
 rubber gloves. 
 
 In addition to the regular monthly inspection the boxes 
 are reweighed quarterly under the supervision of the officer 
 responsible for submarine-mine explosive, and the gross 
 weight so found chalked upon the end. Should any box 
 show any decided decrease in weight the screw cap in the lid 
 is removed, enough fresh water, preferably distilled or rain 
 water, added to bring it up to its original weight, and the 
 screw cap replaced. 
 
SUBMARINE MINING. 71 
 
 Magazines in which guncotton is stored should not be 
 allowed to attain a temperature as high as 100 F. for any 
 length of time. 
 
 Guncotton which is kept wet may deteriorate after long 
 storage, but will not become dangerous. 
 
 Wet guncotton can not be ignited by a flame, but gradually 
 smoulders away as the outer portions in contact with the 
 flame become dried. 
 
 A brownish or reddish shade is sometimes seen in cakes of 
 guncotton. This is due to the presence of iron in the wash 
 water and does not indicate decomposition. 
 
 When storing guncotton in the magazine the piles of boxes 
 should be made so as to give free circulation of air and the 
 greatest convenience in handling consistent with the capacity 
 of the magazine. 
 
 In the event of damage to any case, which may cause loss 
 of water by evaporation, the contents shall be removed at 
 once, repacked in a guncotton box which has been washed 
 with soda solution, the proper amount of water added to 
 the contents, and the box closed. The gross weight shall 
 be marked on the case. In repacking avoid as much as pos- 
 sible handling the cakes with the bare hands. This is for the 
 protection of the guncotton from oil or acid of any kind. 
 Clean cotton or rubber gloves are suitable covering for the 
 hands when engaged on this work. 
 
 If for any reason the cases are subjected to dampness 
 sufficient to cause unusual deterioration of the cases, they 
 should be removed from the magazine and dried, out of the 
 direct rays of the sun. 
 
 Guncotton containing 12 or 15 per cent of moisture may be 
 stored with explosive D, trotol, and dynamite, but never with 
 dry guncotton. 
 
 Empty cases, before being placed in storage, must be 
 washed thoroughly to remove all traces of guncotton. 
 
 For a charge of wet guncotton, the priming charge is dry 
 guncotton. This may be either of crumbled guncotton or 
 cakes made to fit the fuse can. The compressed primer cakes 
 are supplied wet and bored with holes to receive the fuses 
 and the loading wire. 
 
72 SUBMARINE MINING. 
 
 Should the supply of guncotton primers become exhausted 
 fresh ones may be prepared as follows: Two blocks of soft 
 pine are used, one 3 inches square, the other circular and 2.9 
 inches in diameter. A cake of wet guncotton is clamped 
 between these blocks. Using a fine joiners' saw and the cir- 
 cular block as a gauge, a cylinder is sawed from the cake. 
 The cylinder is then smoothed down with a rasp. Four of 
 these are prepared for each charge and in each one of them a 
 hole about T % inch in diameter is bored. While boring the 
 hole the cake must be tightly clamped between two pine 
 blocks to prevent it from splitting; to insure that all the 
 holes will be in alignment it is advisable that the upper 
 wooden block be provided with a T 9 g-inch hole and be thick 
 enough to enable this hole to serve as a guide for the bit. 
 The boring is done with the ordinary bit, which must be 
 sharp, so as to cut clean. It is not safe to saw or bore a dry 
 guncotton cake. 
 
 It is essential that the guncotton primer be thoroughly 
 dry. The primers may be dried by exposure to the air or by 
 means of drying ovens supplied especially for the purpose. 
 To air-dry a primer, it is placed on edge upon a shelf of wire 
 gauze or netting which is hung up indoors where there is a 
 free circulation of dry warm air. Drying should continue 
 until weighings on two successive days show no appreciable 
 loss. This may require a week or more. 
 
 In drying with an oven the cakes are laid on edge on the 
 shelves and the temperature of the oven is kept at about 100 
 F.; it should not exceed 104 F. The heat is provided by 
 means of a bank of lamps placed under the hood and the 
 current of warm air regulated by the size of the lamp bank 
 and the openings in the top of the oven. Under no circum- 
 stances must an open flame be used as a source of heat. The 
 drying in this case also is continued until successive weigh- 
 ings of samples show no appreciable loss. 
 
 Whenever it is necessary to dry more than 50 pounds of 
 guncotton primers for immediate use the guncotton should 
 be placed in the drying oven and exposed to the action of 
 an electric fan placed about 4 feet in front of the open door 
 until the moisture content is reduced to about 6 per cent, 
 
SUBMARINE MINING. 73 
 
 when the drying should be completed by the use of the bank 
 of lamps as described in the preceding paragraph. 
 
 In each case, to test the dryness of the primers, take a cake 
 and split it in four or five pieces and detonate each sepa- 
 rately with a fuse. 
 
 It has been determined that about 5 per cent of water is 
 the maximum content for unconfmed guncotton capable of 
 detonation by a Du Pont No. 30 fuse. 
 
 Priming charges are not to be prepared until just previous 
 to the time they are to be used in loading. When the primers 
 have been dried, they should be kept in well-sealed jars unless 
 they are to be used very soon after drying, in which case they 
 will be stored in assembled fuse cans; when thus stored the 
 assembled fuse cans should be kept in a cool, dry, and secure 
 room away from other explosives. If, however, the primers 
 are to be stored for any length of time, two strips of blue 
 litmus paper are inserted between the cakes, which are in- 
 spected from time to time. If the litmus paper shows de- 
 cided redness, it should be removed and fresh strips inserted. 
 If these strips turn red in a few hours, the primers should be 
 thoroughly wet with fresh water. In general, the period of 
 storage will be short and no particular examination of the 
 dry guncotton will be required. 
 
 Dry guncotton should be handled as little as possible, to 
 prevent crumbling and scattering of guncotton dust. Finely 
 divided guncotton is difficult to remove by brushing and if 
 allowed to collect about a room may give serious trouble by 
 flashing should a portion become ignited. This dust may be 
 removed with a damp sponge or cloth. 
 
 Dry guncotton which is not used as contemplated shall be 
 rewet with the proper amount of water and repacked. 
 
 Samples of each lot of guncotton issued to the service are 
 preserved in the laboratory of the Ordnance Department for 
 chemical test. These retained samples are subjected regu- 
 larly to technical inspection and test by that department to 
 determine their condition as to stability. This will insure 
 the detection of lots that are deteriorating and their removal 
 from the posts or their destruction before they have dete- 
 riorated to such an extent that they become dangerous. 
 
74 SUBMARINE MINING. 
 
 Dynamite. Dynamite cartridges are packed ordinarily in 
 sawdust in wooden boxes. Each cartridge is wrapped in 
 paraffin paper. The cartridges are arranged in the box so 
 that when they are transported all cartridges will lie on 
 their sides and never on their ends. Usually the amount of 
 explosive in a single package will not exceed 50 pounds. 
 
 The boxes must never be allowed to stand so that the 
 cartridges w r ill be vertical. 
 
 Like other nitroglycerin, dynamite freezes at about 40 F., 
 and in its frozen condition is, under ordinary circumstances, 
 less liable to explosion from detonation or percussion than 
 when thawed, but more susceptible to explosion by simple 
 ignition. Should any of the nitroglycerin be exuded, the 
 dynamite cartridges are much more sensitive to explosion 
 by a blow. 
 
 It is important that dynamite cartridges be kept dry. If 
 exposed to a moist atmosphere, there is a tendency of the 
 water, condensed from the air on all exposed surfaces, to 
 displace the nitroglycerin. 
 
 The cases should be raised from the floor on skids and the 
 floor underneath covered with clean sawdust. The sawdust 
 should be removed from time to time, the old sawdust being 
 burned in the open air. 
 
 Kubber gloves should be worn in handling this explosive, 
 or in the absence of rubber gloves cover the hands with 
 grease and wear cotton gloves. This is for the protection 
 of the skin from the injurious effect of nitroglycerin. 
 
 Dynamite may be stored with wet guncotton, explosive D, 
 and trotol. 
 
 Date of receipt at post shall be marked on each box. 
 
 The priming charge for dynamite is a pound of loose 
 dynamite contained in a small bag which fits easily into the 
 fuse can. In filling the bag rubber gloves must be worn. 
 To insert the fuses the bag is opened and the fuses embedded 
 in the explosive, the choke being tied around the fuse wires. 
 
 At the monthly inspection all boxes shall be examined to 
 see if they are dry. If not dry, all shall be exposed to the 
 dry air out of the direct rays of the sun. 
 
SUBMARINE MINING. 75 
 
 The principal source of danger from dynamite is in the 
 exudation of the nitroglycerin. Exudation is indicated by 
 the presence of small white, oily, lustrous globules of liquid, 
 either among the particles of dynamite or on the packages. 
 If such' globules are discovered, they may be identified posi- 
 tively as nitroglycerin by absorbing a drop in a piece of un- 
 glazed paper, which should be placed on an anvil or other 
 piece of metal, and striking it a sharp blow with a hammer. 
 If it be nitroglycerin, an explosion will occur. Another test 
 is to set fire to the paper, and if the liquid be nitroglycerin 
 it will burn with a crackling noise and a greenish-yellow 
 flame. 
 
 If exuded nitroglycerin has stained floors or other ma- 
 terial not readily destroyed, the nitroglycerin may be de- 
 composed and rendered harmless by washing with " sulphur 
 solution." This solution may be made by boiling 50 pounds 
 of lime in a barrel of water and adding powdered sulphur 
 until the solution will take up no more. This will require 
 about 20 pounds of sulphur. The resulting bright orange- 
 colored solution should be filtered and only the filtrate used. 
 A suitable filter for this purpose is a piece of thin cheese- 
 cloth. Sodium carbonate may be used in the place of lime. 
 
 Dynamite may be destroyed by burning in small quantities 
 at a time. Slit the cartridge with a knife, spread out the 
 contents over some straw or shavings, and ignite carefully. 
 Do not attempt to burn frozen dynamite. 
 
 Mine fuses. These are regular commercial electric fuses, 
 extra quality, and each contains about 25 grains of mer- 
 cury fulminate. Fuses are supplied in pasteboard boxes 
 containing 50 each, pasteboard boxes being shipped in suitable 
 wooden boxes. They are supplied with long leads which are 
 cut to proper length when the mines are loaded. They must 
 not ~be stored with other explosives. 
 
 Loading mines. In loading mines the following precau- 
 tions are observed: 
 
 (a) Funnels are used to cover the screw threads. 
 
 (b) Trotol is poured through the funnels. 
 
 (c) Cakes of guncotton or packages of dynamite are 
 passed through the funnels by hand. 
 
76 SUBMAKINE MINING. 
 
 (d) The screw threads are wiped carefully before the 
 compound plug is inserted. 
 
 (e) Pieces of canvas or paulins should be spread upon the 
 floor of the loading room. After the loading has been com- 
 pleted the canvas should be removed and thoroughly cleaned. 
 The floor of the loading room should be scrubbed and all 
 refuse destroyed. 
 
 Unloading mines. Mines charged with trotol or wet gun- 
 cotton may be unloaded without danger; the compound 
 plug being unscrewed, the cakes of wet guncotton are re- 
 moved by hand, repacked in the original boxes, a little fresh 
 water added, and the boxes closed. If loaded with trotol, 
 the charge is poured out into the boxes, which are then 
 closed. Trotol should be inspected carefully when removed 
 from the case, and if there is indication that any of it has 
 undergone a change while the mine was loaded, a report 
 should be made to the War Department. 
 
 In unloading mines charged with dynamite too many pre- 
 cautions can not be taken. The mine should be held either 
 in an opening in a raft or behind an earthen traverse and 
 the compound plug removed by some arrangement which 
 may be operated from a safe distance. If the mine has 
 been planted for some time the recovered dynamite is usu- 
 ally destroyed. Sometimes the interior of the mine case may 
 be found coated with an extremely thin film of exuded nitro- 
 glycerin. This film may be destroyed by filling and thor- 
 oughly rinsing the case with " sulphur solution." 
 
APPENDIX NO. 2. 
 
 THE HORNSBY-AKROYD OIL ENGINE AND GENERATOR. 
 
 (See also Artillery Notes, No. 12.) 
 
 The engine. This is a horizontal, single-acting, single- 
 cylinder kerosene engine, having a flyball governor and oper- 
 ating on a four-stroke cycle. This cycle consists in turn of 
 the explosion on the first outstroke, the expulsion of the prod- 
 ucts of the explosion on the following instroke, the intake 
 into the cylinder of a mixture of air and oil vapor on the 
 following outstroke, and the compression of this explosive 
 mixture on the next instroke. This cycle therefore requires 
 two complete revolutions of the crank shaft for one complete 
 set of operations. 
 
 One one side of the cylinder near the closed end is a valve 
 box containing two valves, the air-inlet valve and the exhaust 
 valve. The air inlet and the exhaust valves are actuated by 
 separate levers, each lever being moved by a cam mounted on 
 a horizontal shaft, driven by the crank shaft through worm 
 gearing. This horizontal shaft makes but one revolution 
 while the crank shaft makes two ; thus the air inlet and the 
 exhaust valves are each opened once every two revolutions 
 of the flywheel. 
 
 At the back of the cylinder, in prolongation of its axis, is a 
 cast-iron box called the vaporizer, which is always open to 
 the cylinder. Before starting the engine this vaporizer must 
 be heated by an external lamp, so that it will vaporize the oil 
 when it is first pumped into it. After the engine has started 
 running, the lamp is no longer required, as the vaporizer is 
 kept at a sufficient heat by the internal explosions. 
 
 A small oil pump, worked by the air-valve lever, draws 
 oil from the oil tank under the engine and forces it into the 
 
 11003 12 7 77 
 
78 SUBMARINE MINING. 
 
 vaporizer at the proper time. The oil, on its way from the 
 pump to the vaporizer, passes through a valve box attached 
 to the vaporizer ; this valve box has two valves in it, a hori- 
 zontal one, kept closed by a spring which the oil forces open 
 as it goes into the vaporizer; the other, a vertical one, also 
 kept closed by a spring. Should the engine run too fast, the 
 governor opens this latter valve and allows some of the oil 
 to flow back to the oil tank through the waste pipe. This 
 valve can also be opened by turning the little regulating 
 handle, which will stop the supply of oil to the vaporizer 
 and thus stop the engine. 
 
 INSTRUCTIONS FOB WORKING. 
 
 Frosty weather. If there is danger of freezing, on shutting 
 down drain the water from the circulating pipes and cylinder 
 jacket, and valve box if water- jacketed; otherwise they may 
 burst or crack. 
 
 Caution, Before starting, see that the cocks which admit 
 water to the water jacket of the vaporizer valve box are 
 open ; that the cock on the main water pipe from the bottom 
 of the water tank is open ; that the water in the tank is above 
 the upper circulating pipe ; that the drain cock is closed ; and 
 that the oil tank is filled with kerosene. Gasoline must not 
 be used with this engine. 
 
 Heating the vaporizer. Open the relief cock on top of the 
 engine cylinder. Place the lamp on the stand under the 
 vaporizer ; fill the lamp with oil by means of the filling pipe 
 till the oil is 1 inch below the pipe ; and put a piece of wick 
 into the cups which are formed around the pipes. These 
 wicks, which should consist of a piece of ordinary asbestos 
 packing, will last for several weeks. Place the lid of the 
 vaporizer cover crosswise on the cover to allow the escape 
 of heated gas and air. 
 
 A little alcohol or kerosene should be poured into the cup 
 under the coil and lighted. The cups may be filled with 
 kerosene by closing the air-escape valve and working the air 
 pump. The pressure forces oil out through the vapor nozzle 
 and it will run down into the cups. When this is nearly 
 
SUBMARINE MINING. 79 
 
 burned out pump up the reservoir with air by the air pump. 
 Oil will issue from the small nozzle and give a clear flame. 
 When it is desired to stop the lamp, turn the thumbscrew on 
 the reservoir filling nozzle to let the air out. Should the 
 nozzle become choked it should be cleaned with the small 
 needles for that purpose. 
 
 The heating of the vaporizer is one of the most important 
 things to be attended to, and care must be taken that it is 
 hot enough at starting. The attendant must see that the 
 lamp is burning properly and that a good clear flame is given 
 off for from 5 to 10 minutes, according to the size of the 
 engine. If, however, the lamp is burning badly, it may take 
 longer to become heated sufficiently. It is important that 
 this should be carefully attended to, for though the engine 
 may start, if the vaporizer is not as hot as it should be the 
 engine will run badly and perhaps soon stop altogether. 
 Failures of engines to run properly can in most cases be 
 traced to this source. 
 
 No time should be lost in starting the engine after the 
 vaporizer has been sufficiently heated, as the engine may not 
 run satisfactorily if the vaporizer is allowed to cool after 
 heating it. The lamp should be left burning a few minutes 
 after starting. 
 
 Oiling the engine. Oiling the engine should always be done 
 during the heating-up of the vaporizer. 
 
 See that the oil cups on the two main crank-shaft bearings 
 are fitted with proper wicks and filled with oil. Adjust the 
 lubricator on the large end of the connecting-rod and oil the 
 small end which is inside the piston. 
 
 Oil also the following: The bearings on the horizontal 
 shaft and the skew gearing, the rollers at the ends of the 
 valve levers and their pins, the pins on which the levers rock, 
 the governor spindles and joints and the bevel wheels which 
 drive the same, and the joints that connect the governor to 
 the vertical valve of the overflow. For such bearings none 
 but the best engine oil should be used. 
 
 It is necessary that a suitable oil should be used for lubri- 
 cating the cylinder, and unless such an oil be used for this 
 
80 SUBMARINE MINING. 
 
 purpose the engine may run badly and perhaps stop alto- 
 gether. Under no circumstances must a thick cylinder oil 
 be used, and the oil must not be used over again on the piston. 
 Do not use ordinary lubricating oil. A high-grade gas- 
 engine oil especially suited to this engine should be used and 
 the piston should be kept flooded with it. 
 
 Starting the engine. Throw the hand lever to u To start." 
 Turn the small crutch-handle regulator Y to the position 
 " Shut " and work the pump lever up and down until oil is 
 seen to pass the overflow freely. Turn the regulator back to 
 " Open," work the pump lever up and down a few strokes. 
 Vapor should issue with some force from the relief cock on 
 the cylinder. This indicates sufficient heat. Close the relief 
 cock and pump a few strokes. Man the flywheel and start 
 the flywheel backward, using the weight of the body if neces- 
 sary, bringing the piston up against compression as sharply 
 as possible, and then release the wheel, when an explosion 
 should take place and the engine start forward. As soon as 
 the engine has sufficient speed to carry it past a full compres- 
 sion, throw the lever to "To work." When full speed is 
 obtained, cut down the pump stroke to correspond to the 
 load, open the oil feeders, and go over the engine carefully, 
 seeing that the cylinder oil feed is working. 
 
 Oil pump. When the cylinder is working at its full power 
 the distance between the round flanges on the pump plunger 
 should be such that the hand gauge (supplied with the en- 
 gine, and to be found in the tool box) will allow the part 
 stamped " 1 " just to fit in between the flanges ; if at any time 
 the positions of these flanges be altered they can be read- 
 justed to this gauge. The other lengths on the hand gauge 
 are useful for adjusting the pump to economize oil. When 
 running on a medium load, use length marked 2 ; on a light 
 load, use length marked 3. See that the pump packing is 
 not too tight. 
 
 Running the engine light. When the engine is to run 
 light that is, with no load or with a light load it is best 
 to alter the stroke of the pump to the amount of oil that will 
 keep the engine running. This amount can be reduced so 
 that the speed of the engine is a few revolutions under the 
 
SUBMARINE MINING. 81 
 
 normal, which will allow the vaporizer to get a small charge 
 each time and keep it from cooling. The cock on the return 
 of the water circulating pipe may be nearly closed to keep 
 the cylinder warmer. These remarks do not apply when the 
 load is intermittent and the engine is running light for a 
 short time only. 
 
 Air-inlet and exhaust valves. See that the air-inlet and 
 the exhaust valves are always working properly and drop 
 onto their seats. They can at any time, if required, be made 
 tight by grinding with a little flour of emery and oil. 
 
 To insure a good seat to the valves when the stems are 
 expanded by heat the stems should clear the set screws on 
 the levers at least -fa inch when the air and the exhaust levers 
 are clear of the cams. A greater clearance is undesirable, as 
 it prevents the full opening of the valves. 
 
 If at any time the air-inlet or the exhaust valves appear to 
 be opening or closing at the wrong time, take off the nut on the 
 end of the lay shaft which holds the skew wheel on and see 
 that the chisel cuts on the shaft are opposite to one another. 
 The lay shaft is coned where the skew wheel is fixed on and 
 it is held on simply by friction, the nut being tightened 
 against it. -i 
 
 Should it at any time become necessary to take out the 
 crank shaft, always be sure that the skew-wheel gearing is 
 put together so that the tooth marked " " on the crank-shaft 
 skew- wheel fits in between the two teeth marked " " on the 
 oil-shaft skew-wheel. 
 
 Vaporizer valve box and pipes attached to vaporizer. In this 
 box there are two valves. The vertical one is regulated by 
 the governor, and when the engine runs faster than its 
 proper speed the governor pushes it down, thus opening it 
 and allowing some oil to return to the oil tank. The hori- 
 zontal valve in this box is a back-pressure valve. If at any 
 time this valve is not working properly, vapor will be seen 
 coming out of the overflow pipe ; in this case the valve should 
 be examined. By screwing off the outside cap the tail of 
 this valve can be seen; if the valve is turned around a few 
 
82 SUBMARINE MINING. 
 
 times it will probably dislodge any dirt that may be under 
 it; if, however, this does not stop the leakage the valve 
 should be taken out for inspection. 
 
 If the horizontal valve and sleeves are taken out at any 
 time, great care must be taken in replacing them to use the 
 same thickness of jointing material as before or the distance 
 the valve opens will be altered. 
 
 See that the pipe from the pump to the vaporizer valve 
 box is inclined upward all the way from the pump. If this 
 is not so, an air pocket will be formed in which a certain 
 amount of air will be compressed upon each stroke of the 
 pump. This will cause the oil to flow in slowly and not 
 suddenly as it should. If the oil tank be emptied of oil at 
 any time, air will get into the suction and delivery pipes of 
 the pump and it will take some time before the oil going 
 through the pump and pipes will be free of this air; for 
 awhile thereafter, the engine will not work properly, as the 
 air, by being compressed as the pump works, will interfere 
 with oil being pumped in suddenly. It is best, if the oil 
 gets below the filter in the tank, to work the pump by hand 
 for about 10 minutes, holding the relief valve (on the vapor- 
 izer box) so as to get air well out of the pipes. 
 
 To stop the engine. Turn the crutch-handle regulator to 
 " Shut." Close the automatic lubricator. If it is desired to 
 stop the engine for a short time only, put the lamp back 
 under the vaporizer to keep it hot. 
 
 Setting the oil engine and the generator. The engine and 
 generator should be so located that the distance from center 
 to center of pulleys should be as nearly correct as possible 
 when the generator is at the middle point of the base rails, so 
 that the proper tension of the belt may be obtained within 
 the limits of adjustment allowed by the rails. 
 
 The two pulleys should be accurately in line and the belt 
 not too tight. The generator base should rest on a wooden 
 frame to separate it from the concrete pier. Both engine 
 and generator should be held firmly in position by anchor 
 bolts. 
 
 For the generator bearings a quantity of the best dynamo 
 oil is furnished ; the commutator should be clean and smooth, 
 
SUBMARINE MINING. 83 
 
 and the brushes should fit the surface. The commutator 
 should be cleaned occasionally with a little paraffin on can- 
 vas, and the brushes should be adjusted, so that when running 
 at full load no sparking occurs. 
 
 All electrical connections should be firmly made and kept 
 thoroughly clean. A cover should be kept on the generator 
 when not in use. If the machine be damp it should be 
 allowed to dry before running at full load. 
 
 NOTE. A few new installations have been supplied with 5-kw. gaso- 
 line electric sets, and future installations will be similarly equipped. 
 Wherever installed, pamphlets on the care and operation of the gaso- 
 line sets have been furnished, containing full instructions for the 
 guidance of those concerned. 
 
APPENDIX NO. 3. 
 THE STORAGE BATTERY. 
 
 (See pamphlets issued by the Electric Storage Battery Co., Philadel- 
 phia, Pa., on General Instructions for the Operation and Care of 
 the Chloride Accumulator.) 
 
 Unpacking material. Great care should be taken in the un- 
 packing and subsequent handling of the various parts of the 
 battery, as many of them are easily broken or bent out of 
 shape by rough handling. 
 
 Open the crates or packing boxes on the side marked " Up " 
 and carefully lift contents out ; never slide them out by turn- 
 ing the crate on its side. 
 
 Upon opening the crates and boxes, carefully count the con- 
 tents of each package, and check with the shipping list. A 
 number of small parts will usually be found in each shipment, 
 and care should be taken to examine the packing materials 
 to determine that no parts have been overlooked. 
 
 Immediately upon opening the crates the materials should 
 be carefully examined for breakage. Cracked jars, whether 
 of glass or rubber, should not be set up, for if put into use 
 leakage of electrolyte may cause annoyance or trouble. 
 
 Location of battery room. The proper location of the bat- 
 tery is important. It should be in a separate room, which 
 should be well ventilated, dry, and of moderate temperature. 
 Extremes of temperature affect the proper working of a bat- 
 tery. The air should be dry, for if damp there is danger of 
 leakage due to grounds. 
 
 The ventilation should be free, not only to insure dryness, 
 but to prevent chance of an explosion, as the gases given off 
 during charge form an explosive mixture if confined. For 
 this reason never bring an exposed flame near the battery 
 when it is gassing. 
 84 
 
SUBMARINE MINING. 85 
 
 Direct sunlight should not fall on the cells. 
 
 The trays, the benches on which the cells ^est, and all 
 metal work (iron and copper) should be painted with as- 
 phaltum varnish. 
 
 Assembling and placing cells in position. Place the jars, 
 after they have been cleaned, in position on the stands, which 
 should be provided for the purpose and which should be so 
 situated in the room that each cell will be easily accessible. 
 The jars are set in the trays, which previously should be 
 filled with fine dry sand even with the top, the trays resting 
 on the glass insulators. 
 
 Place the elements as they come from the packing cases on 
 a convenient stand or table (the elements are packed positive 
 and negative plates together; the positive has plates of a 
 brownish color, the negative of a light gray the negative 
 always has one more plate than the positive), cut the strings 
 that bind them together, and carefully pull the positive and 
 negative groups apart, throwing the packing aside. After 
 carefully looking over both groups and removing any dirt or 
 other foreign matter, assemble them, with separators between 
 each positive and negative plate. 
 
 When putting into the jars be careful that the direction of 
 the lugs is relatively the same in each case, thus causing a 
 positive lug of one cell always to connect with a .negative of 
 the adjoining one, and vice versa. This insures the proper 
 polarity throughout the battery, bringing a positive lug at 
 one free end and a negative at the other. 
 
 Before bolting or clamping the lugs together, they should 
 be well scraped at the point of contact to insure good conduc- 
 tivity and low resistance of the circuit; this should be done 
 before the elements are taken apart and directly after un- 
 packing, if the battery is to be set up at once. The connec- 
 tions should be gone over and tightened several times after 
 the lugs are first fastened together to insure good contact. 
 
 Connecting up the charging circuit. Before putting the 
 electrolyte into the cells, the circuits connecting the battery 
 with the charging source must be complete, care being taken 
 to have the positive pole of the charging source connected 
 with the positive end of the battery. 
 
86 SUBMARINE MINING. 
 
 Electrolyte. The electrolyte is dilute sulphuric acid of a 
 specific gravity of 1.210 or 25 Baume, as shown on the 
 hydrometer at temperature of 70 F. 
 
 The electrolyte should cover the top of the plates by one- 
 half inch to three- fourths inch, and must be cool when 
 poured into the cells. The jars should be numbered with 
 asphaltum varnish and a line made with the same material 
 to indicate the height at which the electrolyte should be kept. 
 
 Initial charge. The charge should be started at the normal 
 rate as soon as the electrolyte is in the cells and continued 
 at the same rate, provided the temperature of the electrolyte 
 is well below 100 F., until there is no further rise or 
 increase in either the voltage or specific gravity over a 
 period of 10 hours, and gas is being given off freely from 
 all the plates. Also, the color of the positive plates should 
 be a dark brown or chocolate and that of the negatives a light 
 neutral gray. The temperature of the electrolyte should be 
 closely watched and, if it approaches 100 F., the charging 
 rate must be reduced or the charge stopped entirely until the 
 temperature stops rising. From 45 to 55 hours at the normal 
 rate will be required to complete the charge ; but if the rate is 
 less, the time will be proportionately increased. The specific 
 gravity will fall rapidly after the electrolyte is added to the 
 cells, and may continue to fall for some time after charging 
 begins. It will finally rise as the charge progresses, until it 
 is again up to 1.210 or possibly slightly higher. The voltage 
 for each cell at the end of charge will be between 2.5 and 2.7 
 volts, and for this reason a fixed or definite volage should 
 not be aimed for. It is of the utmost importance that this 
 charge be complete in every respect. 
 
 At the end of the first charge it is well to discharge the 
 battery about one-half and then immediately recharge it. 
 Repeat this treatment two or three times and the battery 
 will be in proper working condition. 
 
 After the completion of a charge (initial or with the bat- 
 tery in regular service) and the current off, tjie voltage will 
 fall immediately to about 2.20 volts per cell, and then to 2 
 volts when the discharge is started. If the discharge is not 
 begun at once, then the pressure will fall quite rapidly to 
 
SUBMARINE MINING. 87 
 
 about 2.05 volts per cell, and there remain while the battery 
 is on open circuit. 
 
 Battery in regular service. A battery must not be repeat- 
 edly overcharged, undercharged, overdischarged or allowed 
 to stand completely discharged. After the initial charge is 
 completed, the battery is ready to be put into regular service. 
 
 A cell should be selected as a " pilot cell " ; that is, one 
 that is in good condition and representative of the general 
 condition of the battery. The height of the electrolyte in 
 this cell must be kept constant by adding a small quantity of 
 water each day. This cell is to be used particularly in fol- 
 lowing the charge and indicating when it should be stopped. 
 
 When the battery is in regular service, the discharge should 
 not be carried below 1.75 volts per cell at full load. Stand- 
 ing completely discharged will cause permanent injury; 
 therefore the battery should be immediately recharged after 
 a heavy discharge. 
 
 In usual service, with the normal rate, it is advisable to 
 stop the discharge at 1.90 volts per cell. If the discharge 
 rate is considerably less than normal, the voltage should not 
 be allowed to fall as low as 1.90 volts per cell, for the reason 
 that with a very low rate of discharge the voltage will not 
 begin to fall off until the limit of capacity is almost reached. 
 The fall in specific gravity of the electrolyte also serves as 
 an indication of the amount taken out and is in direct pro- 
 portion to the ampere-hour discharge, thereby differing from 
 the drop in voltage, which varies irregularly for different 
 rates and degrees of discharge. For this reason, under ordi- 
 nary conditions, the fall in specific gravity is to be preferred 
 in determining the amount of discharge. 
 
 The actual amount of variation in the specific gravity of 
 the electrolyte between a condition of full charge and a com- 
 plete discharge is dependent upon the quantity of solution in 
 the containing vessel compared with the bulk of the plates. 
 When cells are equipped with the full number of plates, the 
 range will be about 35 points (0.035 sp. gr.) ; for instance, 
 if the maximum specific gravity reached on the preceding 
 overcharge is 1.209, the extreme limit beyond which the dis- 
 charge should not be carried is about 1.174. If the cells have 
 
88 SUBMARINE MINING. 
 
 less than the full number of plates, this range in specific 
 gravity is proportionately reduced, except in the case of the 
 "pilot cell," which should be equipped with a device for 
 displacing the excess electrolyte. 
 
 The available capacity is temporarily reduced at low tem- 
 peratures ; with a return to normal temperature the capacity 
 is regained. 
 
 The battery should preferably be charged at the normal 
 rate. It is important that it should be sufficiently charged, 
 but the charge should not be repeatedly continued beyond 
 that point. Both from the standpoint of efficiency and life 
 of the plates the best practice is the method which embraces 
 what may be called a regular charge, to be given when the 
 battery is from one-half to two-thirds discharged, and an 
 overcharge to be given weekly if it is necessary to charge 
 daily, or once every two weeks if the regular charge is not 
 given so often. 
 
 The regular charge should be continued until the specific 
 gravity of the pilot cells has risen to within five points of the 
 maximum, as shown on the last previous overcharge. For ex- 
 ample, if on the previous overcharge the maximum is 1.210, 
 then on the following regular charges the current should be 
 cut off when the specific gravity of the pilot cell reaches 1.205. 
 The pilot-cell method of noting the end of charge should not 
 be used with a battery unless all the cells are approximately 
 in the same condition. With an old battery whose plates are 
 not uniform, readings should be taken on each cell to deter- 
 mine the end of charge. 
 
 The overcharge should be prolonged until all the cells gas 
 freely and until no rise in the specific gravity and voltage of 
 the pilot cell is shown for five successive 15-minute readings. 
 
 Just before the overcharge the cells should be carefully 
 examined to see that they are free from short circuits. If any 
 short circuits are found they should be removed with a stick 
 or a piece of hard rubber ; do not use metal. 
 
 AJS the temperature affects the specific gravity this must be 
 considered and correction made for any change of tempera- 
 ture. The temperature correction is one point (0.001 sp. g.) 
 for 3 degrees change in temperature. For instance, electro- 
 
SUBMAKINE MINING. 89 
 
 lyte, which is 1.210 at 70, will be 1.213 at 61 and 1.207 
 at 79. 
 
 Inspection. In order that the battery may continue in the 
 best condition it is essential that specific gravity and voltage 
 readings be taken on all cells in the battery at least once a 
 week; the specific gravity readings on the day before the 
 overcharge and the voltage reading near the end ; the voltage 
 readings must always be taken when the current is flowing, 
 open circuit readings being of no value. Also, at the end of 
 each charge it should be noted that all of the cells are gassing 
 moderately and at the end of the overcharge very freely. 
 
 Unevenness of cells; cause and remedy. If any of the cells 
 should read low at either time and do not gas freely with 
 the others at the end of charge, examine them carefully for 
 pieces of scale or foreign matter which may have lodged be- 
 tween the plates. If any are noted, remove them by pushing 
 down into the bottom of the jar with a strip of wood. Never 
 use metal of any kind for this purpose. 
 
 If, after the cause of the trouble has been removed, the 
 readings do not come up at the end of the overcharge, then 
 the cell must be cut out of circuit on the discharge, to be cut 
 in again just before beginning the next charge, during which 
 it should come up all right. 
 
 Impurities in the electrolyte will cause a cell to work 
 irregularly and the plates to deteriorate. Should it be 
 known that any impurity has gotten into the electrolyte, 
 steps should be taken to remove it at once. The solution 
 should be replaced with new immediately, thoroughly flush- 
 ing the cell with water before putting in the new electrolyte. 
 The change should be made when the battery is discharged, 
 for the impurities will be in the electrolyte when the battery 
 is discharged. Immediately after the change the cell should 
 be charged. If in doubt as to whether the electrolyte con- 
 tains impurities, a half -pint sample, taken at the end of dis- 
 charge, should be submitted for test. 
 
 Sediment. The accumulation of sediment in the bottom of 
 the jars must be watched and not allowed under any circum- 
 stances to get up to the plates ; if this occurs, rapid deteriora- 
 tion will result. To remove the sediment, the simplest way, 
 
90 SUBMARINE MINING. 
 
 if the cells are small, is to lift the elements out after the 
 battery has been fully charged, draw off the electrotyte, and 
 then dump the sediment, and clean the jar with water, get- 
 ting the elementvS back and covered with electrolyte again as 
 quickly as possible, so that there will be no chance of the 
 plates drying out. Electrolyte, not water, will be required 
 to complete the filling of the cells, the specific gravity being 
 adjusted to standard (1.210 at the end of charge). 
 
 Evaporation. Do not allow the surface of the electrolyte to 
 get down to the top of the plates; keep it at its proper level 
 (one-half inch to three- fourths inch above the top of the 
 plates) by the addition of pure water ; which should be 
 added at the beginning of a charge, preferably the over- 
 charge. It will not be necessary to add electrolyte except 
 at long intervals or when cleaning, as noted above. Elec- 
 trolyte added to replace loss should be of specific gravity 
 1.210. 
 
 Battery used but occasionally. If the battery is to be used 
 at infrequent periods, it should be given a " freshening " 
 charge every two weeks. 
 
 Putting the battery out of commission. If it is thought best 
 to put the battery out of commission for a time, then it must 
 be treated as follows : After thoroughly charging, syphon off 
 the electrolyte (which may be used again) into convenient 
 receptacles, preferably carboys which have been previously 
 cleaned and have never been used for other kinds of acid, 
 and as each cell becomes empty immediately fill it with fresh, 
 pure water. When water is in all the cells allow them to 
 stand 12 to 15 hours, then draw off the water; the battery 
 may then stand without further attention until it is again 
 to be put into service; then proceed as in the case of the 
 initial charge, as described above. 
 
 If for any reason any cell becomes discharged before the 
 others, it should be cut out on discharge and worked up to 
 normal before being used. 
 
 Should the battery sulphate, charge and discharge fre- 
 quently, not using less than one-half normal rate at any time 
 and increasing to full rate as the plates show signs of 
 
SUBMAKINE MINING. 91 
 
 recuperation ; keep the temperature of the cells below 100 F. 
 Frequent exercise will clear the plates in a badly sulphated 
 battery. 
 
 Keep careful records of all charging voltages, specific 
 gravities, and troubles with the cells. 
 
 The following is a recapitulation of the important points 
 in operating a storage battery: 
 
 CONDENSED INSTRUCTIONS. 
 
 1. Excessive charging must be avoided. A battery should 
 not be undercharged, overdischarged, or allowed to stand 
 completely discharged. 
 
 2. Keep the electrolyte at the proper height above the top 
 of the plates. 
 
 3. The daily and weekly readings should be regularly and 
 accurately taken and recorded. 
 
 4. Inspect each cell of the battery carefully at regular 
 intervals. 
 
 5. If any low cells develop do not delay in bringing them 
 back to condition. 
 
 6. Do not allow the sediment to get up to the plates. 
 
 7. Do not allow impurities, either solid or liquid, to get 
 into or remain in the cells. 
 
 8. Have the battery room well ventilated, especially while 
 charging. 
 
 9. Never bring an exposed flame into the battery room 
 during or shortly after the gassing period of a charge. 
 
 10. Keep the floor and other parts of the battery room 
 clean and dry. 
 
 11. Keep the iron, copper, or other metal work about the 
 battery room free from corrosion. 
 
 12. Keep all connections clean and tight. 
 
 13. Post a copy of these condensed instructions in a con- 
 spicuous place. 
 
APPENDIX NO. 4. 
 SUBMARINE MINE CABLE. 
 
 Submarine mine cable is shipped on reels having an outer 
 sheathing for protection in transit, with at least 12 feet of 
 both ends of the cable brought out and coiled on the head of 
 the reel for test purposes. If the cable is not for imme- 
 diate use, it should be moved to the cable tank, and by means 
 of the overhead trolley and cable tongs put in its position in 
 the tank, the two ends being properly tagged and firmly fixed 
 so as to allow it to be tested. In arranging the multiple 
 cable in the tanks that which is to be used first should be 
 most readily accessible. 
 
 The cable tank should be provided with a cover to keep it 
 clean, as well as to lessen as much as possible variations of 
 temperature. Enough clean water to cover by several inches 
 the outer sheathing of the cable reels should be kept in the 
 tanks, but in climates where the water in the cable tanks 
 would normally freeze to a depth exceeding 2 feet, the water 
 should be let out of the tanks before ice begins to form and 
 not again admitted until the following spring. In localities 
 where the tanks may become a breeding place for mosquitoes, 
 as a preventive measure, salt water from the ocean or bay 
 should, when practicable, be used for filling the tanks, or 
 where it is necessary to use fresh water sufficient salt should 
 be added to produce a 3 per cent solution. No oil or kerosene 
 should be used in the tanks. 
 
 The methods of recording tests and of classifying and 
 transferring submarine mine cable are prescribed by orders 
 from the War Department. The tests of submarine mine 
 cable at posts will consist in determining the insulation and 
 conductor resistances. 
 
 The insulation surrounding the conductor of a cable is 
 supposed to be uniform in regard to quality of material, 
 92 
 
SUBMARINE MINING. 93 
 
 density, and thickness. The resistance which it offers to 
 the passage of a current through it will then vary inversely 
 with its length. In comparison the insulation resistance of 
 1 mile of cable is taken as the standard. This insulation has 
 a large negative temperature coefficient; that is, an increase 
 of temperature lowers its resistance. It is customary to 
 reduce all insulation resistance to that at a standard tempera- 
 ture of 60 F., and for this purpose reduction factors ap- 
 plicable to the particular insulation compound should be 
 furnished with the cable. (Note : It has been found that for 
 most compounds, if the logarithms of the resistance are plot- 
 ted as ordinates against the temperature in degrees F. as 
 abscissae, the resulting curve will be very nearly a straight 
 line. ) 
 
 The ordinary methods of measuring resistance that is, by 
 means of a Wheatstone bridge, or by fall of potential, or by 
 voltmeter can not be used in measuring resistance as high 
 as that of the insulation of a submarine cable. For this the 
 direct deflection method is employed. 
 
 In brief, this consists of the following steps : 
 
 First. The deflection produced in a galvanometer by a cur- 
 rent from a battery through a known resistance, usually 
 100,000 ohms, is determined, whence is calculated the resist- 
 ance through which this same battery would produce a deflec- 
 tion of one point using the unity shunt. This is expressed in 
 megohms and is called the galvanometer " constant " under 
 the conditions. 
 
 Second. The deflection produced by the current from the 
 same battery through the insulation of the cable is deter- 
 mined, whence, from " First," the corresponding number of 
 megohms is calculated. 
 
 Third. This multiplied by the length of the cable in miles 
 and corrected for temperature gives the required insulation 
 resistance per mile. 
 
 This testing can be made most satisfactorily on dry days, 
 but a close adherence to the instructions herein given relative 
 to the preparation of the cable ends, the insulation of the 
 cable lead and of the battery, and the drying out of the test 
 room and instruments should enable satisfactory work to be 
 
 11003 12 8 
 
94 SUBMARINE MINING. 
 
 done under adverse conditions of weather or climate. The 
 following apparatus is required: Reflecting galvanometer, 
 universal shunt, special testing key, 100,000-ohm resistance 
 box, battery of dry cells giving approximately 100 volts, and 
 stop watch. 
 
 Figure 16 shows diagrammatically the arrangement of the 
 apparatus for testing a reel of cable. As a rule the instru- 
 ments should* be so placed that one person may manipulate 
 the key and* the shunt while at the same time observing the 
 galvanometer. 
 
 The 100,000-ohm box, as a protection to the galvanometer 
 in testing, is always kept in the circuit and its value should be 
 subtracted from the resistance determined, except in the case 
 of high insulation resistance when it will not be necessary 
 to make the subtraction. 
 
 The universal shunt is always employed with the galva- 
 nometer and is used both to vary the current through the lat- 
 ter and to protect it from a violent throw at the instant of 
 making or breaking the circuit at the testing key. This last 
 is accomplished by having the shunt on zero at such times. 
 
 The galvanometer being a very sensitive instrument must 
 be solidly supported so as to be free from jars or vibrations. 
 
 The special testing key, shown diagrammatically in the fig- 
 ure, has its binding posts plainly marked. It is a double 
 throw key and has two positions upon each side. When 
 completely closed to the right, the cable is charged through 
 the galvanometer from the positive pole; when to the left, 
 from the negative pole of the battery. In each case the 
 deflection of the galvanometer is in the same direction. When 
 partly closed on either side, the cable is discharged to earth 
 through the galvanometer. (Note: It will be observed that 
 the connections are such that the galvanometer is always con- 
 nected to the cable*core and never to the ground. With this 
 connection, so long as the lead PX is free from leaks or 
 grounds, the galvanometer measures only the current actu- 
 ally passing through the core and not that leaking through 
 any imperfect insulation in the battery and leads.) 
 
 Cable testing is a very simple operation, but extreme care 
 is necessary in all operations. 
 
SUBMARINE MINING. 95 
 
 The following is a detailed description: 
 
 1. Preparing the cable for testing. 1. Closely examine each 
 conductor end. Look particularly for unusually hard or 
 brittle insulation and for torn, pinched, or punctured insula- 
 tion, especially near the ends of the armor wires. If any of 
 the ends are not in perfect condition, cut off enough cable to 
 secure good ends. (Caution. Do not cut off more than 
 enough to secure good ends, for after three or four tests it 
 may be necessary to unreel the whole cable to secure enough 
 of the inner end above water.) 
 
 2. Verify the tagging. Remember that the " shore end " is 
 the end from the outer coils on the reel and is numbered 
 clockwise. The other end is numbered contraclockwise. 
 
 3. The " ground " should be made by taking several turns 
 of bare copper wire around the armor of the cable to be tested 
 and soldering them in position. One such ground in each 
 tank is sufficient. Whenever " ground " or " earth " is sub- 
 sequently spoken of, this ground in the tank is meant, and 
 not a connection to ground at some point outside the tank. 
 
 4. The leads PX and BY (fig. 16) should be of loading 
 or other heavily insulated wire. They must be carefully 
 insulated from each other, from the ground, and from the 
 walls or other parts of buildings. This is especially true of 
 the cable lead PX. In damp weather porcelain-knob insu- 
 lators and porcelain tubes (the latter for use in passing 
 through walls or partitions) may not be sufficient to afford 
 proper insulation for the cable lead. In such case the latter 
 should be suspended in the air from the testing switch to the 
 cable tank by means of several chains of paraffined porcelain 
 insulators suspended by marline or protective tape which has 
 been boiled in paraffin. These suspensions should be in each 
 case under cover and should be kept as dry as possible. The 
 length of the leads is immaterial. If loading wire is used, 
 the distance between supports should be short (not over 50 
 feet) , as this wire stretches considerably from its own weight, 
 pulling out the insulation and giving a very thin wall, par- 
 ticularly at points of support. Extreme care should be taken 
 to tighten up on the knob insulators, in case they are used, 
 just enough to hold the wire without pinching the insulation. 
 
96 SUBMARINE MINING. 
 
 5. Using a double connector, join the lead BY to the ground 
 wire on the cable above the surface of the water. Put a con- 
 nector on the end of the other lead so that it can be readily 
 attached in turn to each conductor. 
 
 6. Any protective covering, such as armor, jute, etc., should 
 be removed from the ends of the conductors for a distance of 
 about 12 inches, thus laying the insulation coating bare. 
 This latter should not be handled and must be kept scrupu- 
 lously clean. With a clean dry knife prepare each conductor 
 of the cable to be tested by cutting off about 1 inch of the 
 insulation from each end of the wire and then tapering the 
 end of the insulation for about 1 inch, leaving a perfectly 
 clean surface. In damp weather dip each end of each con- 
 ductor into melted paraffin (not boiling, but heated above 
 212 F.). Secure one end of the cable so that it is well sep- 
 arated from the surrounding objects and separate the con- 
 ductors so that no ends, are touching. 
 
 7. Take one strand of a loading wire about 4 feet long 
 and wrap it two or three times around the projecting copper 
 end of each conductor at the other end of the cable, then 
 connect it to earth. See that the conductors at this end are 
 dry. Leave the lead PX disconnected and suspended in 
 the air. 
 
 II. Setting up the testing apparatus. 1. Select a light, dry 
 room as near the cable tank as practicable. 
 
 2. Use dry cells for the battery. The voltage of the bat- 
 tery should be such as to give a full scale deflection of the 
 galvanometer through the resistance employed for taking the 
 constant (with shunt at jinxr)- Large galvanometer throws 
 are essential for reliable results. 
 
 Set up the cells on shelves in a small closed closet or box, 
 with narrow strips of wood or heavy cardboard laid between 
 each row of cells, lengthwise and crosswise. The height of 
 each strip should be about half the height of a cell, so that 
 the two layers of strips will come nearly to the tops of the 
 cells and keep them well separated. Wire the cells in series 
 and bring the terminals out to a double-pole single-throw 
 switch, which should be on a heavy porcelain or slate base 
 
SUBMAKINE MINING. 97 
 
 and rated for at least 250 volts. (It may be found desirable 
 to install some electric lamps in the closet to keep the battery 
 dry.) 
 
 If difficulty is experienced in eliminating grounds from the 
 battery set up in this manner, the battery box should be sus- 
 pended in air by means of chains of paraffined cleats. 
 
 3. Set up the galvanometer on a pier or on a window sill 
 if the building is of masonry. It should be insulated by 
 placing its feet on a slate or ebonite slab, or in glass insu- 
 lators. Remove the cover. Adjust the level until the sus- 
 pended coil hangs freely. Maneuver the suspended coil, by 
 means of the knob at the top of the tube, until its face is 
 parallel with the face of the instrument. Then adjust the 
 level until the upper suspension hangs in the center of the 
 supporting tube, and the air gap between the coil and arma- 
 ture is symmetrical. Replace the cover. Put on the scale 
 and the telescope. Turn the mirror so that it reflects the 
 of the scale approximately, getting exact adjustment by mov- 
 ing the scale. Be careful (particularly in dry weather) not 
 to touch the glass of the cover or to do anything which will 
 produce a static charge on the glass. 
 
 The galvanometer scales are usually graduated in equal 
 divisions corresponding to 1 millimeter on the circum- 
 ference of a circle whose radius is 1 meter. Each tenth 
 division is usually marked with a number. This number is 
 sometimes 1 instead of 10, 2 instead of 20, and so on. The 
 number of divisions to read and record is the number of 
 smallest (millimeter) divisions. Do not try to read closer 
 than \ of one division. The larger the throw the less the 
 personal error. No accurate conclusion can be drawn from 
 a very small throw. 
 
 4. Place a table or low shelf conveniently to one side and 
 place the shunt, the testing key, the T ^ megohm box, and a 
 voltmeter on it. The apparatus should be insulated by an 
 ebonite or slate slab, or glass insulators. Fasten the shunt 
 and the key securely to the table or the shelf. (The use of 
 paraffin paper for insulating instruments is a makeshift at 
 best. It soon gets soiled and creased, then it has to be 
 replaced.) 
 
98 SUBMARINE MINING. 
 
 The use of lamps to keep the apparatus dry may be desir- 
 able, or it may be found convenient to expose the apparatus 
 to the sun for a few minutes before beginning the test on any 
 day. The use in the testing room of a small stove or of a 
 gasoline torch for two or three hours before the beginning of 
 the testing will ordinarily prove very advantageous. 
 
 5. Wire up as in figure 16, except that the leads from the 
 testing key should be carried to the battery through the 
 double-pole single- throw switch above referred to. (The 
 battery switch should be opened whenever any connections 
 are made or altered.) All leads used in connecting up the 
 instruments should be of heavy copper, and stiff enough to 
 hold permanently any shape to which they are bent. They 
 should be supported at points of connection only, and should 
 not lie on the table or within an inch of each other. 
 
 III. Testing the insulation of the apparatus. 1. Voltmeter 
 test of battery insulation. This is a rough test, but should 
 be included. A serious ground can be much more quickly 
 located with a voltmeter than with the galvanometer. 
 
 (a) Disconnect the battery leads at the battery switch ; con- 
 nect + lead of battery to + post of the voltmeter; connect 
 the B end of the lead BY to post of the voltmeter ; lead 
 of the battery should be in the air. Close the voltmeter 
 switch and read. 
 
 (b) Disconnect the voltmeter. Connect lead of the 
 battery to post of the voltmeter. Connect the B end of 
 the lead BY to + post of the voltmeter; -f lead of the bat- 
 tery should be in the air. Close the voltmeter switch and 
 read. 
 
 If any deflection is obtained in either case, the battery 
 or its connections are grounded. Locate and remove the 
 ground. (See Foster or some other practical handbook.) 
 
 2. Testing the battery voltage. Connect the voltmeter 
 across the battery terminals. Read and record the voltage. 
 (If there is no voltmeter available which will read as high 
 as the battery voltage, take the voltage of the battery in sec- 
 tions and add, or make a multiplier of one of the resistance 
 coils in the $ megohm box.) 
 
SUBMARINE MINING. 99 
 
 3. Testing the battery and the apparatus for grounds with 
 the galvanometer. With a camel's-hair brush go over all 
 the instruments and carefully remove dust. See that the 
 instruments and connections are dry. Do not blow on the 
 instruments. 
 
 Open the battery switch. Connect the battery leads to the 
 battery switch. Disconnect lead PX at P and connect the 
 earth leads BY and EY to the key at " cable post:' ( Y is 
 grounded.) Both battery leads are left connected to the key. 
 The shunt should be on 0. Close the battery switch. Close 
 the testing key to the right. Turn the shunt gradually to 
 the unity post. The galvanometer deflection should be zero. 
 Turn the shunt to 0. Reverse the testing key. Turn the 
 shunt to the unity post. The deflection should be zero. If 
 any deflection is obtained, there is a ground in the battery, 
 the apparatus, or the connections. The tesft of the cable 
 should not proceed if a deflection is obtained in either posi- 
 tion of the key. 
 
 In reporting the voltage + to earth and to earth as 
 " zero " on form, it will be understood that this means zero 
 using the galvanometer, as herein described. 
 
 4. Insulation of leads. Turn the shunt to 0. Open the 
 battery switch. Connect the earth leads BY and E Y to their 
 proper posts. Connect the cable lead, PX, to " cable " post. 
 See that the cable tank ends of the lead PX is disconnected 
 at X and suspended in the air. Close the battery switch. 
 Close the key and turn the shunt to the unity post. Deflec- 
 tions should be as small as possible and in any case must be 
 steady and uniform for several trials. Turn the shunt to 0. 
 Reverse the key, stopping at the discharge position. Turn 
 the shunt to the unity post and wait until the galvanometer 
 rests at 0, indicating that the leads are discharged. Turn the 
 shunt to 0. Close the key all the way down. Turn the shunt 
 to the unity post. The deflection should not differ materially 
 from that noted above. If there is a deflection, the trouble is 
 in the lead PX or its connections. Go over these, carefully 
 examining for dust and moisture and noting particularly the 
 proximity of all wires of opposite potential which cross or 
 lie near each other. If there is a small deflection which can 
 
100 SUBMAKINE MINING. 
 
 not be removed, a correction must be applied subsequently 
 to the deflection obtained in the test for the insulation resist- 
 ance of the conductor. 
 
 Using proper care, there are very few days when perfect 
 insulation of the instruments can not be secured. The lead 
 leakage with well-insulated wire put up properly will be 
 noticed rarely. 
 
 5. Use of Price guard-wire. As an additional precaution 
 against surface leakage across the insulation at the ends of 
 the conductor it will sometimes be advisable to install an 
 additional lead (not necessarily as carefully insulated as 
 PX) running from the testing switch to the cable under 
 test. This lead should be connected in at the testing switch 
 to the post carrying the lower blade between " D " and " C " 
 (fig. 16) ; the tank end should be bare of insulation for a 
 sufficient distance to enable the bare wire to be wrapped 
 firmly, without pinching, around the insulation at each end 
 of the particular conductor under test, just below the tapered 
 portion. 
 
 The potential difference between the cable core and this 
 guard-wire is thus made practically nil, so that any leakage 
 will be from the guard-wire to the tank, consequently this 
 leakage will not be measured by the galvanometer. 
 
 IV. Take the galvanometer constant as follows: Open the 
 battery switch. 
 
 With a short piece of wire connect the hinge post of the 
 testing key marked " cable " to either " earth " post of the 
 key, the leads to the cable tank being disconnected at E, B, 
 and P. Turn the shunt to 0. Examine the -^ megohm box 
 and see that all the resistance coils are in the circuit. Close 
 the battery switch and the testing key. Turn the shunt to 
 the T oVc post. Watch the swing of the galvanometer and 
 when it has come to rest, read and record. Turn the shunt 
 to 0. The galvanometer should return exactly to 0. If it 
 does not, readjust and repeat until it does. The galvanome- 
 ter constant is numerically equal to the total throw in smallest 
 divisions of the scale multiplied by 100. Remove the con- 
 necting wire and replace the leads to the tank. 
 
SUBMARINE MINING. 101 
 
 If at any subsequent time during the test the galvanometer 
 adjustment is disturbed that is, if it does not return accu- 
 rately to zero when the shunt is at the constant should be 
 redetermined. 
 
 V. Testing the cable. 1. See that the testing key is open 
 and the shunt at 0. Connect the earth lead to ground on 
 the cable armor. Remove the earth connection from No. 1 
 conductor and connect the cable lead to this conductor; in 
 wet weather the connector joint should be dipped in melted 
 paraffin. (In using paraffin to insulate joints or ends bring 
 it just above 212 F. to evaporate any moisture present. 
 It should not be boiling. The paraffin coating should be at 
 least as thick as the rubber insulation and extend back over 
 the rubber for an inch or more.) 
 
 2. Close the testing key to the left (-f- to earth), stopping 
 at the discharge position, and turn the shunt to the unity 
 post. There should be no deflection. If there is, it is due 
 either to a charge on the cable, which will disappear after a 
 moment, or to earth currents. (It is assumed that the test- 
 ing apparatus has been thoroughly tested for insulation.) 
 If due to earth currents, the conductor is probably a poor 
 one. Earth currents are readily recognizable by their fluc- 
 tuating character. Before assuming that the trouble can not 
 be removed, the joint between the lead and the conductor 
 should be examined again. Moisture on the cable end will 
 give a path for earth currents. Note the value and direc- 
 tion of the throw of the galvanometer and record it. 
 
 3. Turn the shunt to 0, close the testing key all the way 
 down (-f- to earth), noting the time to the second, or start- 
 ing the stop watch at the same time, if one is available. The 
 time must be accurately noted. The insulation resistance at 
 the end of one minute's electrification is the resistance to be 
 reported. 
 
 4. When 35 seconds have elapsed, turn the shunt to the 
 T tfW-post and watch the galvanometer throw ; if small, move 
 the shunt successively to the rfo-post, to the T Vpost, and to 
 the unity post. This operation must be completed before 45 
 seconds have elapsed from the time the key was closed. With 
 
102 SUBMARINE MINING. 
 
 good cable the unity post will always be reached without 
 danger of throwing the galvanometer reading off the scale. 
 Remember that each successive post should give 10 times 
 the throw of the preceding post. 
 
 5. At the end of one minute read the deflection, correct for 
 the leakage of the leads and the earth currents, and record. 
 (See example following.) 
 
 6. At the end of two minutes read the deflection, correct 
 and record it. For good cable it should be less than the de- 
 flection observed at the end of one minute. 
 
 7. Turn the shunt to 0, and reverse the key, stopping at the 
 discharge position. Turn the shunt on gradually until the 
 unity post is reached and wait until the reading is 0, 
 indicating that the conductor is discharged. If earth cur- 
 rents are present, will not be reached or w r ill be passed. In 
 this case proceed as before described. A submarine-mine 
 cable conductor a mile long will discharge ordinarily in 
 about three minutes. 
 
 8. Turn the shunt to 0, stop and start the stop watch; at 
 the same time close the key all the way down ( to earth). 
 
 9. After 35 seconds, start turning the shunt, ceasing at 45 
 seconds. ( See paragraph 4, above. ) 
 
 10. At the end of one minute read the deflection, correct 
 and record it. For good cable it should be substantially 
 the same as the deflection observed at the end of one minute 
 with -f of the battery to earth. 
 
 11. Turn the shunt to 0, and reverse the key, stopping at 
 the discharge position. 
 
 12. Disconnect No. 2 conductor from ground. Disconnect 
 No. 1 from the lead and connect up No. 2. Connect No. 1 to 
 ground. It is not necessary to wait for No. 1 to be dis- 
 charged completely before disconnecting it. 
 
 13. Proceed with No. 2 as with No. 1 and repeat with each 
 conductor. 
 
 14. On the completion of the test all conductor ends should 
 be carefully taped. 
 
 15. To determine the correct value of the insulation resist- 
 ance it is essential that the negative pole of the battery be 
 
SUBMARINE MINING. 103 
 
 connected to the core of the cable, otherwise the products of 
 electrolysis will tend to seal up any fault which may exist and 
 will cause the conductor to appear better than it really is. 
 With the negative pole of the battery to the core the tendency 
 is to deposit copper on the core and thus to lay bare any fault. 
 The insulation resistance of any conductor is therefore found 
 by multiplying the corrected deflection at the end of one 
 minute, with + of battery to earth, by the denominator of 
 the shunt used, and then dividing the galvanometer constant 
 by this product. The resistance of the T Vmegohm box is 
 neglected unless the insulation resistance determined is very 
 low, say, under 1 megohm, when the 100,000 ohms should 
 be subtracted from the above quotient. 
 
 16. To determine the insulation resistance per mile at 60 
 F., multiply the actual insulation resistance found by the 
 length of the cable in miles, and this result by the multiplier 
 furnished by the torpedo depot for the particular make of 
 cable, corresponding to the temperature of the water in the 
 tank observed during test. 
 
 Example. Leakage of the leads found to be one-half 
 division. Earth currents found to give 1J divisions in a 
 negative direction from of the scale. Galvanometer throw 
 at the end of one minute (+ to earth), 15 divisions. The 
 corrected deflection is, 15 J-|-1J=16 divisions. 
 
 The galvanometer constant (450 divisions through T ^ 
 megohm, shunt at ioW)) 45,000 megohms. That is, the 
 battery will give -^ f 450 divisions=45 through 1 megohm, 
 the shunt at T ^TT > or, what is the same thing, one division 
 through 45 megohms, the shunt at y^^ ; therefore with 
 the shunt at unity the battery will give one division through 
 45X1,00045,000 megohms. The insulation resistance^- 
 45,000-^-16=2,813 megohms. If the cable is three-fourths 
 mile long, the insulation resistance in megohms per mile is 
 2,813X1=2,110 megohms. 
 
 Manufacturer, Safety Insulated Wire & Cable Co. 
 
 Temperature of water in tank, 80 F. 
 
104 SUBMARINE MINING. 
 
 Multiplier, 1.7056; 2,110X1.7056=3,599 megohms insula- 
 tion resistance per mile at 60 F. This result is recorded 
 on the form. 
 
 VI. Copper resistance. 1. The drop of potential method is 
 quicker than the bridge method under the usual conditions 
 and should be used if the apparatus is available. 
 
 Apparatus required. (a) Source of power (110 volts 
 D. C. lighting circuit, casemate battery or generator) ; (b) a 
 double-pole single-throw switch to which the power leads are 
 attached; (c) a bank of ten 110-volt lamps in parallel; (d) a 
 D. C. ammeter of not more than 0-25 scale; (e) a D. C. 
 voltmeter, 0-150 scale. 
 
 Place the lamp bank and the ammeter in one side of the 
 power line from the switch to the conductor, and the other 
 end of the conductor to the other side of the power line. 
 Connect the voltmeter across the ends of the cable so as to 
 measure the drop of potential between the ends of the con- 
 ductor being tested. Close the switch, take simultaneous 
 readings on the voltmeter and the ammeter and calculate the 
 resistance. With the apparatus described a conductor 1 mile 
 long will receive about 2J amperes and show a drop of about 
 50 volts. The lamps are inserted as a safety precaution. In 
 no case should the current through the conductor exceed 6 
 amperes. If the cable has been tested for insulation resist- 
 ance and all the conductors show high insulation, the lamps 
 are not necessary, provided the cable is at least a mile long. 
 
 2. The copper resistance found is reduced to that at 60 F. 
 by multiplying by the coefficient found in the following table 
 with the temperature of the water in the tank at the time 
 of the test as an argument : 
 
SUBMARINE MINING. 
 Reduction of copper resistance to 60 F 
 
 105 
 
 Tem- 
 pera- 
 ture. 
 
 S 
 
 Tem- 
 pera- 
 ture. 
 
 8 
 
 Tem- 
 pera- 
 ture. 
 
 d 
 
 10 
 
 1252 
 
 40 
 
 1.0468 
 
 70 
 
 .9781 
 
 11 
 
 1224 
 
 41 
 
 1.0443 
 
 71 
 
 .9759 
 
 12 
 
 1196 
 
 42 
 
 1.0419 
 
 72 
 
 .9738 
 
 13 
 
 1168 
 
 43 
 
 1. 0395 
 
 73 
 
 .9717 
 
 14 
 
 1141 
 
 44 
 
 1. 0371 
 
 74 
 
 .9695 
 
 15 
 
 1113 
 
 45 
 
 1.0347 
 
 75 
 
 .9674 
 
 16 
 
 1086 
 
 46 
 
 1.0323 
 
 76 
 
 .9653 
 
 17 
 
 1059 
 
 47 
 
 1.0300 
 
 77 
 
 .9632 
 
 18 
 
 .1032 
 
 48 
 
 1. 0276 
 
 78 
 
 .9611 
 
 19 
 
 .1005 
 
 49 
 
 1. 0252 
 
 79 
 
 .9591 
 
 20 
 
 .0978 
 
 50 
 
 1.0229 
 
 80 
 
 .9570 
 
 21 
 
 .0952 
 
 51 
 
 1.0206 
 
 81 
 
 .9549 
 
 22 
 
 .0925 
 
 52 
 
 1.0182 
 
 82 
 
 .9529 
 
 23 
 
 .0899 
 
 53 
 
 1. 0159 
 
 83 
 
 .9508 
 
 24 
 
 .0873 
 
 54 
 
 1.0136 
 
 84 
 
 .9488 
 
 25 
 
 .0846 
 
 55 
 
 1.0113 
 
 85 
 
 .9468 
 
 26 
 
 .0820 
 
 56 
 
 1.0090 
 
 86 
 
 .9448 
 
 27 
 
 .0794 
 
 57 
 
 1.0068 
 
 87 
 
 .9428 
 
 28 
 
 .0769 
 
 58 
 
 1.0045 
 
 88 
 
 .9408 
 
 29 
 
 .0743 
 
 59 
 
 1.0023 
 
 89 
 
 .9388 
 
 30 
 
 .0717 
 
 60 
 
 1.0000 
 
 90 
 
 .9368 
 
 31 
 
 .0692 
 
 61 
 
 .9978 
 
 91 
 
 .9348 
 
 32 
 
 .0667 
 
 62 
 
 .9956 
 
 92 
 
 .9328 
 
 33 
 
 .0641 
 
 63 
 
 .9933 
 
 93 
 
 .9308 
 
 34 
 
 1.0616 
 
 64 
 
 .9911 
 
 94 
 
 .9288 
 
 35 
 
 1. 0591 
 
 65 
 
 .9889 
 
 95 
 
 .9269 
 
 36 
 
 1.0566 
 
 66 
 
 .9867 
 
 96 
 
 .9250 
 
 37 
 
 1.0542 
 
 67 
 
 .9846 
 
 97 
 
 .9231 
 
 38 
 
 1.0517 
 
 68 
 
 .9824 
 
 98 
 
 .9211 
 
 39 
 
 1.0492 
 
 69 
 
 .9802 
 
 99 
 
 .9192 
 
 The true length of a cable should be that of its center 
 conductor. 
 
 From the size of the conductor and its copper resistance 
 the length of the cable may be computed by use of the follow- 
 ing wire table : 
 
 Table of resistances of pure copper wire at 60 F. 
 
 Size 
 B.&S. 
 
 Dia.in 
 mils. 
 
 Ohms per 
 1,000 feet. 
 
 Size 
 B.&S. 
 
 Dia. in 
 mils. 
 
 Ohms per 
 1,000 feet. 
 
 1 
 
 289 
 
 0.11999 
 
 16 
 
 51 
 
 3.8880 
 
 2 
 
 258 
 
 . 15130 
 
 17 
 
 45 
 
 4.9030 
 
 3 
 
 229 
 
 .19080 
 
 18 
 
 40 
 
 6. 1827 
 
 4 
 
 204 
 
 .24058 
 
 19 
 
 36 
 
 7.8024 
 
 5 
 
 182 
 
 .30338 
 
 20 
 
 32 
 
 9. 8316 
 
 6 
 
 162 
 
 .38256 
 
 21 
 
 28.5 
 
 12. 397 
 
 7 
 
 144 
 
 .48245 
 
 22 
 
 25.3 
 
 15. 625 
 
 8 
 
 128 
 
 .60831 
 
 23 
 
 22.6 
 
 19. 712 
 
 9 
 
 114 
 
 .76696 
 
 24 
 
 20.1 
 
 24. 857 
 
 10 
 
 102 
 
 .96740 
 
 25 
 
 17.9 
 
 31. 343 
 
 11 
 
 91 
 
 1.21960 
 
 26 
 
 15.9 
 
 39. 535 
 
 12 
 
 81 
 
 1. 5379 
 
 27 
 
 14.2 
 
 49. 839 
 
 13 
 
 72 
 
 1. 9393 
 
 28 
 
 12.6 
 
 62. 848 
 
 14 
 
 64 
 
 2. 4453 
 
 29 
 
 11.3 
 
 79. 250 
 
 15 
 
 57 
 
 3.0134 
 
 30 
 
 10.0 
 
 99. 932 
 
106 SUBMARINE MINING. 
 
 The objections to the use of a bridge for measuring copper 
 resistance are the difficulty of eliminating the resistance of 
 the plug contacts and the time required to secure balance. 
 The resistance of the plug contacts may often be as high as 
 20 ohms, particularly if used at the tank. 
 
 If the bridge is used at all, it should be placed in the test- 
 ing room, and the same leads employed for testing insulation 
 should be used. The resistance of these leads should first be 
 determined by connecting them together and measuring; 
 this resistance is subtracted from each resistance measured. 
 
 VII. General. The key to success in cable testing is great 
 care in every detail. The cable now being furnished is all 
 tested with galvanometers having constants from 200,000 to 
 250,000 megohms. It has all been accepted after most care- 
 ful test. The chances are that it is good when it arrives at 
 the post, unless it has been mechanically injured in transit, 
 which should be ascertained by careful inspection when de- 
 livered at the posit. 
 
 Do not accept a single measurement if it shows low resist- 
 ance, but repeat until certain of results. The time between 
 trials on the same conductor should be as great as practicable. 
 For example : Measurements showing low resistance made in 
 the morning should be repeated in the afternoon ; those made 
 in the afternoon should be repeated the next day; the con- 
 ductor being connected to earth during the interval between 
 tests. 
 
APPENDIX NO. 5. 
 
 CARE AND PRESERVATION OF SUBMARINE MINE 
 MATERIEL. 
 
 Frequent inspections of all articles of submarine mine 
 equipment should be made, not only to check up the prop- 
 erty, but also to determine the condition of all materiel, 
 and especially to see if it has been affected by dampness. 
 These inspections should be thorough and detailed, as only in 
 this manner can there be impressed on those directly charged 
 with the care of the property the importance of ventilation, 
 dryness, and the proper use of preservatives. 
 
 The generating set, storage battery, motor-generators, case- 
 mate transformers, power panel, and operating boards will 
 be installed in the mining casemate, and such tools, appli- 
 ances, and materials as may be used when this apparatus is in 
 commission will also be kept there. 
 
 The explosive will be kept in the magazines and tested and 
 cared for in the manner prescribed in Appendix No. 1. 
 
 The multiple and single conductor cable will be kept in the 
 cable tanks as* described in Appendix No. 4. 
 
 All other articles of equipment will ordinarily be kept in 
 the storehouse, and a noncommissioned officer will be placed 
 directly in charge. It shall be his duty to keep the materiel 
 in the best possible condition, using such details from the 
 submarine mine detachment from time to time as may be 
 necessary to assist him in this work. He shall check up all 
 articles taken from the storehouse during practice and report 
 at the end of the day's work any shortage in tools or appli- 
 ances that he may discover. 
 
 Paints and oils should be kept separate from other stores, 
 and the floor where kept should be covered with 2 or 3 inches 
 
 11003 12 9 107 
 
108 SUBMARINE MINING. 
 
 of sand, to be renewed occasionally. Sawdust should never 
 be used for this purpose. Cotton waste which has become 
 unfit for use should be promptly burned. Fuses must not be 
 stored with other explosives. 
 
 Gasoline in considerable quantites should be stored in tanks 
 underground and never inside of buildings. Small quanti- 
 ties should be kept outside of buildings in some safe place. 
 
 When oil engines or generators are out of commission, 
 their bright parts should be covered with light slushing 
 oil. Brass screw threads and parts of tools that are liable 
 to rust should be covered also. In all cases the light slush- 
 ing oil should be applied in a thin coast, since this is all 
 that is necessary to give good protection. Before applying 
 the light slushing oil to any surface it should be thoroughly 
 cleaned, so as to be free from rust, water, kerosense, and 
 lubricating oil, as their presence will cause rusting under- 
 neath the slushing oil. The protected surfaces should be 
 occasionally inspected and the coating of slushing oil re- 
 newed as often as required. 
 
 Screw threads of mine cases, steel screw threads of com- 
 pound plugs, bolts, nuts and washers, and surfaces of flat 
 joints should be kept coated with the light slushing oil or a 
 mixture of machine oil and graphite. 
 
 No oils or grease should ever be placed on points where 
 metallic contact of electrical instruments is necessary, nor 
 on india rubber, ebonite, or slate. 
 
 Mine cases should rest on racks or skids, and where space 
 permits should not be in contact with each other. In hand- 
 ling mine cases care must be taken not to damage the bails 
 and bolts. They should be arranged so that the holes in the 
 mine cases can be seen easily; these holes should be fitted 
 with a wooden plug which has been thoroughly greased all 
 over its surface. New mine cases, if galvanized, usually will 
 not need painting until they have been in the water. When 
 taken from the water they should be thoroughly dried, and 
 if they should show signs of rust they should be gone over 
 thoroughly with steel wire brushes until the rust is removed. 
 Parts which can not be reached with the brush should be 
 cleaned with three-cornered steel scrapers. A heavy coat of 
 
SUBMARINE MINING. 109 
 
 red lead should then be applied. Seven gallons of this paint 
 can be made by mixing 100 pounds of red lead ground in oil 
 with 5 gallons of raw linseed oil. This mixture should be 
 applied within two or three weeks after mixing. One gallon 
 of paint should give 10 mine cases one coat. After this coat 
 has been allowed to dry there should be applied a coat of 
 white lead toned down to a neutral gray. Seven gallons of 
 this paint can be made by mixing 100 pounds white lead, 2J 
 gallons raw linseed oil, 2J gallons turpentine, 1 gallon liquid 
 drier, and adding about 1 pound of lampblack to tone down 
 the mixture. 
 
 Mines treated in this way, if kept in a dry storehouse, and 
 not put in the water, should not require repainting for sev- 
 eral years. Frequent inspection should be made, however, 
 for in handling the cases and changing their positions on the 
 racks, it will often happen that an abrasion will be made in 
 the surface of the paint, which if neglected may serve as the 
 starting point of a progressive corrosion, which may extend 
 rapidly under the surface of the paint. Should loose paint 
 or rust be seen the case should be repainted. A small wooden 
 mallet may be used to tap the case at all points to loosen 
 scales of rust or paint ; then the surface should be thoroughly 
 wire brushed or scraped and the cases repainted as stated 
 above. The inside of mine cases must be inspected to see 
 that the interior surfaces are kept free from rust. 
 
 Ground mines and ground-mine buoys should be treated in 
 the manner just described for buoyant-mine cases. 
 
 If the oil engine has not been painted, it should be given a 
 priming coat of red lead mixed in oil. This should be 
 rubbed down with pumice stone and two coats of steel- 
 colored paint applied. The second coat should be rubbed 
 down and two coats of varnish then applied. After this the 
 engine should not need repainting for a couple of years. 
 When, however, repainting is necessary, the engine should 
 be rubbed down until all the varnish is removed and a coat 
 of steel-colored paint applied. This coat should be rubbed 
 until no brush marks remain, and one or two coats of varnish 
 should then be applied. The steel-colored paint should be 
 applied flat; that is, the color which is ground in japan 
 
110 SUBMARINE MINING. 
 
 should be mixed with turpentine. One gallon of this paint 
 is more than sufficient to give an engine two coats. 
 
 The motor-generators and the casemate transformers usu- 
 ally will not need the priming coat of red lead, as they come 
 from the factory painted. When it is necessary to paint 
 them, one coat of the steel-colored paint and one of varnish 
 will usually be found sufficient. 
 
 Anchors, distribution boxes, junction boxes, mooring sock- 
 ets, shackles, sister hooks, and the ironwork of operating 
 boards and power panels should be painted with asphaltum 
 varnish. 
 
 Paint brushes when new, and before /use, should be wrapped 
 or bridled with strong twine and soaked in water to swell. 
 After use they should be cleaned with turpentine and put 
 away in water to keep them from drying and becoming 
 unpliable. 
 
 Large ropes should be stored on skids, allowing a free cir- 
 culation of air. Small ropes should be hung on wooden 
 pins. Ropes should be uncoiled semiannually in dry seasons 
 and stretched out for several days to dry. Wire rope must 
 be stored in a dry place where it will not rust. Marline- 
 covered wire rope should be stored where there is a fair cir- 
 culation of air. The date of receipt should be stenciled on 
 each reel. If not used at the end of five years it should be 
 run through a bath of pure distilled tar oil. This may be 
 done by setting up an empty reel 20 feet in front of the full 
 reel and placing a tub of the tar oil midway between them. 
 As the rope comes off the full reel it is passed through the 
 oil and the surplus oil slicked off with a piece of burlap, 
 thus returning the oil to the bath. The freshly oiled reel 
 will continue to drip for several days, and sand should be 
 put on the floor under the reel to take up the excess oil. After 
 use in water the marline-covered rope should be thoroughly 
 dried out and then reoiled as above described. 
 
APPENDIX NO. 6. 
 
 INSTRUCTIONS FOE MASTERS OF MINE PLANTERS. 
 
 The matter contained in this appendix is primarily for 
 the information of the masters of those vessels which are 
 called into service for mine-planting purposes upon the out- 
 break or threatening of hostilities. 
 
 The master shall request to be supplied with a copy of 
 Regulations for Mine Planters, U. S. Army. 
 
 To each vessel will be assigned a coast artillery officer, who 
 shall be the commanding officer of the vessel. All orders for 
 the vessel shall be given to and through him. He shall have 
 general charge of its business and be responsible for the 
 proper care and disposition of all stores aboard, leaving to 
 the master of the vessel the full and unquestioned control 
 and authority over all matters for which he is professionally 
 responsible. 
 
 Any orders to be given by the commanding officer concern- 
 ing the vessel or its crew will be given to or through the 
 master, except that when planting mines or operating any 
 of the mining appliances or machinery aboard the vessel, the 
 commanding officer, or an officer designated by him, may 
 give instructions directly to any of the vessel's officers or to 
 members of the vessel's crew who have duties directly con- 
 nected with the mining work. 
 
 The duties and responsibilities of the master of a vessel 
 engaged in submarine mine work do not differ materially 
 from those devolving upon him when his vessel is otherwise 
 employed. With respect to every duty the vessel may be 
 called upon to perform, it may be stated that explicit direc- 
 tions as to where the vessel is to go and just what maneuvers 
 it is to execute in the mine field will be given by the officer 
 
 ill 
 
112 SUBMARINE MINING. 
 
 aboard, and it is then incumbent upon the master to execute 
 the maneuver according to his best judgment. 
 
 The duties that vessels employed as mine planters are likely 
 to be called upon to perform are as follows: 
 
 1. To lay out the mine fields. 
 
 2. To lay the multiple cable. 
 
 3. To plant mines. 
 
 4. To take up mines (including replacing defective mines 
 by good ones where necessary). 
 
 5. To take up the cable. 
 
 The commanding officer of the vessel is responsible for the 
 proper equipment of the vessel with the necessary apparatus 
 for mine planting, for the loading of all the materiel prior 
 to the planting, and for the method of procedure under the 
 above heads. 
 
 The master of the vessel will carry out the orders of the 
 commanding officer and is concerned only in the handling of 
 his boat to prevent accidents to it and to the boats engaged 
 in the planting. 
 
 The following precautions will be observed by masters : 
 
 1. If current flows across the mine field the planting vessel, 
 to avoid accidents, should always pass on the downstream 
 side of the yawl boat holding the measuring line. 
 
 2. The greatest care should be taken that the measuring 
 line and buoy ropes are not caught in the propellers. If 
 the vessel has twin screws, the upstream propeller should 
 be stopped as soon as the measuring line has been passed 
 to the marking boat. In all cases a man with a boat hook 
 should be posted near the anchor davits and another amid- 
 ships, to hold the measuring line above the water and clear 
 of the sides of the vessel. Keg buoys, and as much of the 
 buoy rope as possible, should be held on the rail near the 
 stern, letting the rope pay out slowly and under tension, 
 until the propellers are past the rope, then the keg and the 
 remainder of the rope may be thrown overboard. 
 
 3. A general rule is never to back either propeller when 
 buoy ropes, measuring lines, or cables are being handled 
 overboard at or near the stern of the vessel. 
 
SUBMAKINE MINING. 113 
 
 4. If it becomes absolutely necessary to reverse the pro- 
 pellers when paying out cable, men paying it out must haul 
 it in taut and keep it above the wheel and clear of it. The 
 planting vessel should not pass nearer than 25 feet to the dis- 
 tribution-box boat when cable is leading out from the latter, 
 nor should it pass over any cable, if it can be avoided, if the 
 depth is less than 16 feet. 
 
 5. The vessel should proceed after passing the distribution- 
 box boat on such a course that cable will pay off smoothly 
 without becoming entangled. If a cable becomes fouled and 
 entangled, the end should be "let go" at once at the dis- 
 tribution-box boat the planter should proceed on, not stop 
 nor back its propellers. Mine cable should never be made 
 fast in the distribution-box boat until after a mine is dropped. 
 It is much better to drop the mine out of position than to en- 
 danger the propellers of the vessel. The propeller nearest 
 the distribution box should be stopped the moment the bow 
 of the vessel passes the distribution-box boat on its course to 
 drop a mine. 
 
 6. If, in planting, the vessel moves against the direction of 
 the current, there is little danger of overturning the distribu- 
 tion-box boat if ordinary caution is observed. Should it be 
 necessary to plant against a cross current or with it, it is best 
 to pass the cable end to the distribution-box boat by a launch 
 or small boat. In this way the planter need not pass within 
 50 or 75 yards of the boat. 
 
 7. To avoid getting foul of the buoy rope or mine after 
 the mine is dropped, the helm should be put over so as to 
 throw the stern away from the mine. The vessel should be 
 under good headway so that the propellers may be stopped 
 until they are well past the buoy and buoy ropes of the mine. 
 These points are important; failure to observe them will 
 result disastrously. 
 
 In laying multiple cable, the course of the vessel invariably 
 should be against the current. Rather than lay cable with 
 the current it is advisable to postpone laying the cable until 
 a change of the tide causes a favorable direction of current. 
 In the end, time will be saved by waiting. Cable should pay 
 
114 SUBMARINE MINING. 
 
 off on the upstream side of the vessel if any cross current is 
 running. All care should be taken that the cable does not get 
 caught in the vessel's propellers. This is of the greatest im- 
 portance. 
 
 As the cable pays out over a chock near the bow of the ves- 
 sel a man should stand by with a 3-inch strap in readiness to 
 stop the cable should it be necessary, and two men should 
 manipulate brakes to prevent the cable from paying out too 
 rapidly. This is especially necessary if the water is deeper 
 than 50 feet. 
 
 Especial care is necessary in planting mines to avoid: (a) 
 Colliding with yawl or distribution-box boat; (b) picking up 
 cable in the propeller; (c) getting the mine cable tangled; 
 (d) drifting over the mine after it is dropped. 
 
APPENDIX NO. 7. 
 MANUAL FOR SMALL BOATS. 
 
 The left-hand side of a boat or ship, looking toward the 
 bow, is the port side, and the other is the starboard side. 
 The men who row on the port side are called the port oars 
 and those rowing on the starboard side are called the star- 
 board oars. 
 
 Boats are called single or double banked, according as they 
 have one or two oarsmen to a thwart. 
 
 Thwarts are the seats on which the crew sits; the space 
 abaft the after thwart is called the stern sheet. 
 
 Floorings and gratings are the bottom boards of a boat. 
 They prevent the weight from bearing directly upon the 
 planking. 
 
 The gunwale of a boat is the upper rail. 
 
 The yoke is an athwartship piece of w r ood or metal fitting 
 over the rudderhead. 
 
 Yoke lanyards are the small lines made fast to the ends of 
 the yoke, by which the rudder is turned and the boat steered. 
 
 The stem is the upturned portion of the keel at the bow of 
 the boat, to which the forward ends of the planks are secured. 
 
 Oars are said to be double-banked when two men pull 
 one oar. 
 
 The blade of an oar is the broad flattened part. The 
 handle is the small part of an oar on the inboard end of the 
 loom, which the oarsman grasps when pulling. The loom 
 is the portion of an oar extending from the blade to the 
 handle. The leather is the portion of an oar which rests in 
 the rowlock. This is sometimes covered with canvas, but is 
 usually covered with leather ; hence the name. 
 
 Feathering is the term applied to the operation of turning 
 the blades nearly flat to the water after the stroke, with the 
 upper edge turned forward, especially valuable in rowing 
 against a head wind. 
 
 115 
 
116 SUBMARINE MINING. 
 
 Rowlocks are forked pieces of metal in which the leather 
 of the oars rests while pulling. Swivel rowlocks are mov- 
 able, a pin on the rowlock fitting into a socket in the gunwale. 
 
 Thole pins are pins set vertically in the gunwale and are 
 used in place of rowlocks. 
 
 The steering rowlock is a peculiar form of swivel rowlock 
 (fitted near the stern of a boat) in which the steering oar is 
 shipped. This is sometimes called a crutch. 
 
 The painter is a rope secured in the bow for towing or for 
 securing the boat. 
 
 Boat-falls are tackles made with two blocks and a length 
 of rope ; used for hoisting boats. 
 
 The plug is the wooden stopper fitted into a hole in the 
 bottom of a boat to let water in or out. 
 
 A boat breaker is a small keg used for carrying fresh water. 
 
 A boat-recall is an understood signal made to order a boat's 
 return. 
 
 BOAT ORDERS. 
 
 Oars and rowlocks having been placed in the boat, blades 
 of oars toward the bow, rudder and yoke, if any, stepped and 
 the yoke lanyards clear, the men board and take their proper 
 seats. The man pulling the bow-oar is No. 1, the next man 
 is No. 2, and so on, to the man pulling the stern-oar, who is 
 called the "stroke-oar." The men being seated, with oars 
 handy, the bow-man, who may be No. 1 or an extra man, as 
 convenient, holds onto the wharf, side, or piling, as the case 
 may be, with his boat hook. 
 
 Shove off. At this command the bow-man shoves the boat 
 clear, giving her headway if possible. He boats his boat 
 hook and takes his seat. 
 
 Up oars. The crew simultaneously seize and raise their 
 oars smartly to the vertical (guiding on the stroke-oar) and 
 hold them directly in front of them, the blades fore-and-aft, 
 inboard hands grasping the handles, holding the same well 
 down between the knees, outboard hands grasping the loom? 
 at the height of the chin. 
 
 Let fall. The oars are eased down into the rowlocks to- 
 gether, brought level with the gunwale, blades horizontal and 
 
SUBMARINE MINING. 117 
 
 all trimmed on the after oars. Oars must not be allowed to 
 splash. 
 
 (1) Give way together, (2) GIVE WAY. 
 
 At the first command the men reach well forward, blades 
 nearly vertical, ready for the stroke. At the second com- 
 mand they dip their oars at the same time as the stroke oar 
 and commence rowing, keeping stroke exactly and all lifting 
 their blades to the height of the gunwale on the return. (Or 
 higher if waves render this necessary.) 
 
 TO MAKE A LANDING. 
 
 In running alongside a vessel or up to a float-stage or 
 wharf, w T hen several lengths away from same, give* the com- 
 mand (while the oars are in the water), IN BOWS. The 
 bow oarsman (if there be no extra man in the bow) finishes 
 his stroke, then " tosses " and " boats " his oar, blade to 
 the bow, and stands ready with the boat hook to fend off 
 and hold the landing. When there is sufficient headway to 
 carry the boat properly to the landing, give the command, 
 WAY ENOUGH. This order is given while the oars are 
 in the water; the men finish the stroke, then toss and boat 
 their oars with as little noise as possible. The oars are next 
 the rail, the after-oars outboard of the bow oars. If the 
 stroke oarsman is provided with a boat hook, he grasps it 
 and stands ready to help the bow man. 
 
 If it be desired to stop rowing temporarily, give the pre- 
 paratory command, (1) Stand l>y to lay on oars, at which 
 the crew pays strict attention. Then, when ready, give (2) 
 OARS. At this command, given while the oars are in the 
 water, the crew finishes the stroke and brings the oars level 
 with the gunwale, blades horizontal, trimmed on the after 
 oars. This position is also used for salutes, as noted here- 
 after. 
 
 If about to pass so close to another boat that a collision of 
 oars seems probable, command (1) Trail, (2) OARS. At the 
 second command, given while the oars are in the water, the 
 men finish the stroke, and then, while the oars are still in 
 the water, by lifting the handles with their outboard hands. 
 
118 SUBMARINE MINING. 
 
 the looms are thrown out of the rowlocks. The men carry 
 their hands outboard till the backs of their wrists rest on the 
 rails and the oars trail astern. (This movement is used in 
 shooting bridges, where lack of head room precludes tossing.} 
 
 To bring the oars inboard, command : OARS. 
 
 At this command the men raise the handles, lower the 
 looms into the rowlocks, and then raise the blades out of the 
 water and swing the oars to the regular position of Let fall. 
 
 In order to turn the boat short around (being stationary 
 or nearly so) command: (1) Give way, starboard; 'back port. 
 (2) GIVE WAY; or (1) Give way, port; back, starboard, 
 (2) GIVE WAY. The crew keeps stroke just as regularly 
 as in pulling straight away. As soon as the boat points in 
 the desired direction command: (1) Give way together, (2) 
 GIVE WAY. 
 
 If it be desired to check the boat's headway, command: 
 HOLD WATER. At this command the men drop their 
 blades vertically into the water, tops of blades inclined 
 slightly forward, inboard hands grasping the handles, out- 
 board arms over the looms to steady the oars against the 
 chest. To prepare the crew for rowing command OARS, 
 at which they resume the position described under the head- 
 ing Let fall. 
 
 To move the boat astern command STERN ALL. 
 
 At this command the men back water, keeping stroke as 
 regularly as in ordinary rowing. To resume the position of 
 attention give the command OARS, as before. 
 
 To toss oars command: (1) Stand ~by to toss, (2) TOSS. 
 
 The command of execution is given while the oars are in 
 the water, the stroke is completed and the oars raised smartly 
 to the vertical, with blades in fore and aft plane, handles of 
 oars on bottom boards, the wrists of the inboard hands rest- 
 ing on the thighs, outboard hands grasping the looms at the 
 height of the chin, crew sitting upright. To place the oars 
 in the boat give the command BOAT YOUR OARS. At 
 this command the oars are lowered toward the bow (not 
 swung outboard) and laid in the boat as before described. 
 This command may be given from the position of Let fall, 
 in which case the men toss their oars and proceed as above. 
 
SUBMAKINE MINING. 119 
 
 NOTES. 
 
 In rowing the blade of the oar should be raised as high as 
 the gunwale after leaving the water and feathered by drop- 
 ping the wrist. A barely perceptible pause should be made, 
 and the oar next thrown well forward and dropped edgewise 
 into the water, taking care to avoid splashing and chopping. 
 Now swing the oar smartly through the water without giving 
 it any final jerk, and repeat as above. With green crews it 
 may be found necessary for the coxswain to call stroke, stroke, 
 in order to get the men to pull exactly together. 
 
 There should be a mark on the loom of the oar (about the 
 height of the eyes when the oar is at toss) to show when the 
 blade is fore-and-aft, thus avoiding the necessity of the men 
 gazing up for the purpose of finding out when this is the case. 
 Never allow a boat's crew to splash with the blades when 
 executing Let fall. When resting on oars, insist that they be 
 kept level with the gunwale and at right angles to the keel. 
 Talking among the crew and turning the heads to look at any 
 object should never be allowed while the boat is under way. 
 In most cases, boats should be permanently equipped with a 
 small breaker of fresh water, a spare oar and oarlock and a 
 suitable anchor or grapnel. The anchor rope to withstand a 
 storm should be six (6) times as long as the greatest depth 
 liable to be used as an anchorage. For any small boat in our 
 service a 20-pound anchor and 12-thread (about 1 inch) 
 manila hawser should easily weather a hurricane. A boat 
 should never go out at night without a good, well-filled lan- 
 tern. Many a boat has been run down through its inability 
 to make its presence known. Before leaving the shore in 
 foggy weather, provide the boat with some sort of a foghorn 
 and a compass, and calculate as nearly as possible the bear- 
 ings of the landing you wish to make. Take the opposite of 
 this upon returning, making due allowance for tide and wind 
 in both cases. To ride out a gale of wind in an open boat, 
 lash the oars and grating together, making them into a 
 bulky bundle and weight them if possible ; span them with the 
 painter and pitch them overboarcL This will keep the boat's 
 head to the sea and prevent her from drifting fast. Assist 
 the boat to take the seas head-on by means of a steering oar. 
 
120 SUBMARINE MINING. 
 
 In rowing through a chop, where the rudder is apt to be 
 pitched clear of the water, it should be unshipped and a steer- 
 ing oar used instead. Remember, in making a landing, that 
 the heavier the boat is laden the longer she will keep her way. 
 If you are being towed by a steamer, make her give you a 
 line, instead of using your own, and belay it so it can be cast 
 off in a hurry. Carefully avoid weighing down the bow; 
 always use a short towline when the boat is empty and a long 
 towline when the boat is laden. If the boat's painter is used 
 for a towline, have a knife ready for cutting it if it becomes 
 necessary. Never go close under a steamer's stern unless it 
 is absolutely unavoidable. 
 
 Officers in boarding a ship, use the starboard gangway, 
 although they may use the port gangway. Enlisted men use 
 the port gangway or the booms, unless otherwise ordered. 
 
 Boat salutes. The following salutes should be exchanged 
 between boats meeting or passing each other. No junior 
 should pass ahead of a senior without permission. 
 
 The junior should always salute first, and the senior should 
 return the salute by touching his cap. 
 
 Salutes should be exchanged whenever boats pass near 
 enough to each other for the senior officer to be recognized, 
 whether he be in uniform or not. 
 
 Officers without a flag or pennant flying should be saluted 
 with the hand only; those with a flag or pennant flying 
 should, in addition, be saluted by laying on oars. 
 
 When a noncommissioned officer is in a boat and meets 
 another boat containing an officer he stands and salutes. If 
 the boat flies a flag or pennant, the noncommissioned officer, 
 in addition, lays on oars. 
 
 Officers of the Navy and Marine Corps and foreign officers 
 in boats should always be saluted when recognized. 
 
 In laden boats, towing boats, or boats under sail the hand 
 salute only is made on all occasions. 
 
 Coxswains in charge of boats shall always rise and salute 
 when officers enter or leave their boats. 
 
 Boat keepers shall stand up and salute officers passing in 
 boats and remain standing until the boat has come alongside 
 or passed. 
 
APPENDIX NO. 8. 
 SUPPLY LIST. 
 
 APPARATUS. 
 
 Ammeters, portable, 0-25 scale, 1 to each post. 
 Anchors, buoy, 500 pounds, 5 to each group of 19 mines. 
 Anchors, mine, 1 to each buoyant mine. 
 Axle, cable-reel, 1 to each cable-reel frame. 
 Balances and weights, 1 set to each post. 
 Battery, storage, 1 to each casemate. 
 Boards, operating, 1 to each group of 19 mines. 
 Boxes, distribution, 1 to each group of 19 mines. 
 Boxes, distribution, 1 to each group of 7 mines. 
 Boxes, junction, large, 3 to each mile of multiple cable. 
 Boxes, junction, small, 1 to each mile of single-conductor cable. 
 Buoy, distribution-box, 1 to each distribution box. 
 Buoy, marking, 5 to each group of 19 mines. 
 Buoy, mine, 1 to each buoyant mine. 
 Cable, submarine, 19-conductor, according to project. 
 Cable, submarine, 7-conductor, according to project. 
 Cable, submarine, 1 conductor, according to project. 
 Cases, gun cotton, as required. 
 Circuit closer, 1 to each mine transformer. 
 Clips, cable, 2 for each mine. 
 Engine, internal combustion, 1 to each casemate. 
 Frame, cable-reel, 3 to each post. 
 Fuse can, 1 to each compound plug. 
 Generator, casemate, 1 to each casemate. 
 Mine cases, according to project. 
 Motor generator, D. C.-A. C., 2 to each casemate. 
 Panels, power, 1 to each casemate. 
 
 Planting equipment for emergency vessels, 1 to each vessel : 
 Each planting equipment consists of 
 
 1 axle, cable-reel. 
 4 blocks, snatch. 
 
 4 blocks, triplex, 2-ton. 
 
 2 corne-alongs. 
 
 2 davits, anchor. 
 2 davits, mine. 
 1 frame, cable-reel. 
 4 hooks, trip. 
 
 121 
 
122 SUBMARINE MINING. 
 
 Plugs, compound, 1 to each mine case. 
 Heels, cable, according to cable on hand. 
 Reel and frame, measuring, 1 to each mine field. 
 Shackles, anchor, 2 to each anchor. 
 Shackles, mine, 2 to each mine. 
 Sister hooks, 1 pair to each anchor. 
 
 Sockets, mooring, 2 to each buoyant mine, for wire rope only. 
 Springs, automatic anchor, 6 extra for each group of 19 mines. 
 Switches, starting, 1 to each motor generator, D. C.-A. C. 
 Telephones, boat, 4 to each mine field. 
 
 Testing set, insulation, 1 to each post having a cable tank : 
 Each testing set consists of 
 
 1 box, resistance, 100,000 ohms. 
 
 2 cases for instruments. 
 
 1 galvanometer, D'Arsonval, reflecting. 
 
 1 key, special insulation testing. 
 
 1 repair kit. 
 
 1 shunt, Ayrton Universal. 
 Transformer, casemate, 2 to each casemate. 
 Transformer, mine, 1 to each mine. 
 
 Voltmeter, portable, 0-3-volt scale, 1 to each storage battery. 
 Voltmeter, portable, 0-150-volt scale, 2 to each post. 
 Weights, distance, for automatic anchor, 6 extra for each group of 19 
 mines. 
 
 UTENSILS. 
 
 (Supply for each post, unless otherwise indicated.) 
 
 1 anvil, 50-pound. 
 3 axes, handled. 
 6 basins, wash. 
 
 24 binding posts (to each casemate). 
 
 2 blocks, tackle, double. 
 2 blocks, tackle, single. 
 6 boxes, tool. 
 
 6 brushes, battery. 
 
 6 brushes, dust. 
 
 6 brushes, paint, flat. 
 
 6 brushes, paint, oval. 
 
 12 brushes, sash. 
 
 12 brushes, scratch. 
 
 6 buckets, galvanized iron. 
 
 1 chest, carpenter's tool : 
 
 The chest contains the following tools 
 
 1 bits, set, of 13. 
 
 1 bit, expansive, 
 
 1 brace, ratchet. 
 
 1 chisels, carpenter's, set of 6. 
 
SUBMARINE MINING. 123 
 
 1 chest, carpenter's tool Continued. 
 
 The chest contains the following tools Continued. 
 
 1 hammer, claw. 
 
 1 knife, drawing. 
 
 1 level, carpenter's. 
 
 1 oilstone. 
 
 1 plane, jack. 
 
 1 plane, smooth. 
 
 1 rule, 2-foot. 
 
 1 saw, compass. 
 
 1 saw, hand. 
 
 1 saw, rip. 
 
 1 saw set. 
 
 1 square, carpenter's. 
 6 chisels, cold. 
 
 4 clips, wire rope (for each buoyant mine). 
 4 coppers, soldering. 
 3 crowbars. 
 6 cups, drinking. 
 
 2 cutters, cable. 
 
 1 dies, letters, set. 
 
 1 dies, numbers, set. 
 
 1 drill, breast. 
 
 1 drill points, set of 15. 
 
 6 files, 6-inch, flat bastard. 
 
 3 files, 6-inch, slim taper. 
 6 funnels, loading, large. 
 6 funnels, loading, small. 
 
 1 gloves, rubber, pair (to each storage battery). 
 
 1 grindstone. 
 
 24 hacksaw blades. 
 
 4 hacksaw frames. 
 
 6 hammers, ball peen. 
 6 hammers, smith's. 
 
 2 handles, with tools. 
 
 3 hatchets. 
 
 6 hooks, boat. 
 
 2 hydrometers, battery (to each storage battery). 
 
 3 irons, calking. 
 
 4 irons, grappling. 
 
 120 knives, submarine mine (for each mine company, to be issued as 
 
 part of equipment). 
 3 ladles. 
 6 lamps, alcohol. 
 
 2 lamps, battery inspection (to each storage battery). 
 
 3 lamps, Khotal. 
 
 5 leads, sounding. 
 
 M003 12 10 
 
124 SUBMARINE MINING. 
 
 12 levers for socket wrenches. 
 
 12 life buoys. 
 
 12 life-preservers. 
 
 2 mallets, large. 
 
 2 mallets, small. 
 
 12 marlinspikes. 
 
 6 megaphones. 
 
 1 oilers and tray, set (to each casemate). 
 12 padlocks, brass, with chain. 
 
 2 pitchers, acid (to each storage battery). 
 
 2 plates, earth. 
 
 70 pliers, side cutting, 5 inch (for each mine company, to be issued 
 
 as part of equipment). 
 50 pliers, side cutting, 8-inch (for each mine company, to be issued 
 
 as part of equipment). 
 
 3 pots, melting. 
 
 4 pumps, boat (to each mine field). 
 
 2 scales, extension spring, reading 200 pounds. 
 
 1 scales, portable platform. 
 6 scissors, 8-inch. 
 
 6 scoops, large, for trotol only. 
 
 6 scoops, small, for trotol only. 
 
 12 scrapers, iron, with handle. 
 
 4 screw-drivers, large. 
 
 4 screw-drivers, medium. 
 
 4 screw-drivers, small. 
 
 6 switches, assorted (to each casemate). 
 
 2 syringes, battery (to each storage battery). 
 
 3 tapes, measuring. 
 
 2 thermometers, battery (to each storage battery). 
 
 2 thermometers, cable tank. 
 
 2 thimbles, galvanized iron (to each buoyant mine case). 
 
 2 tongs, cable reel. 
 
 6 torches, gasoline, hand. 
 
 2 trucks, mine case. 
 6 vises, bench, large. 
 
 6 wrenches, monkey, 8-inch. 
 6 wrenches, monkey, 15-inch. 
 12 wrenches, S. 
 6 wrenches, socket. 
 6 wrenches, spanner. 
 
 3 wrenches, Still son. 
 6 wrenches, T, small. 
 
 EXPENDABLE STORES. 
 
 Alcohol, wood, 5 gallons to each post. 
 
 Antimony for socket alloy, 10 pounds to each 19 mines. 
 
 Books, record of cable test, 1 to each post. 
 
SUBMARINE MINING. 125 
 
 Books, daily test, 2 to each post. 
 
 Books, note, 24 to each post. 
 
 Brushes, carbon, 4 extra for each machine requiring them. 
 
 Brushes, wire, 4 extra for each machine requiring them. 
 
 Cells, dry, large, 25 to each post. 
 
 Cells, dry, small, 100 to each post. 
 
 Cement, rubber, 3 pounds to each 19 mines. 
 
 Cleats, porcelain, 1-wire, 50 to each casemate. 
 
 Cleats, porcelain, 2-wire, 50 to each casemate. 
 
 Collars, Turk's-head, large, 10 to each mile of 7-conductor cable. 
 
 Collars, Turk's-head, medium, 10 to each mile of 19-conductor cable. 
 
 Collars, Turk's-head, small, 5 to each mine. 
 
 Compound, commutator, 1 stick to each casemate. 
 
 Connectors, double, 25 to each casemate. 
 
 Cords, telephone, 4 extra. 
 
 Crayons, marking, 12 to each storehouse. 
 
 Cut-outs, porcelain, 2 to each casemate. 
 
 Drier, as required. 
 
 Electrolyte, specific gravity 1210, 4 carboys to each casemate, 
 
 Explosive, according to project. 
 
 Fuses, service, 4 to each mine. 
 
 Gasoline, for torches, 10 gallons to each post. 
 
 Glands for compound plugs, 2 extra for each plug. 
 
 Glue, 5 pounds to each post. 
 
 Graphite, as required. 
 
 Handles, assorted, as required for repairing tools. 
 
 Insulators, glass, 25 to each storehouse. 
 
 Jointers, copper, 1 pound to each 19 mines. 
 
 Keys, distribution box, flat, 4 extra to each box. 
 
 Keys, distribution box, split, 4 extra to each box. 
 
 Keys, mine case, 2 extra for each mine case. 
 
 Keys, shackle, 1 extra to each shackle. 
 
 Knobs, porcelain, 100 to each post. 
 
 Lampblack, 2 pounds to each 100 pounds of white lead. 
 
 Lamps, incandescent, white, 110 volts, 16-candlepower, 12 to each case- 
 mate. 
 
 Lamps, incandescent, white, 80 volts, 16-candlepower, 12 to each case- 
 mate. 
 
 Lamps, incandescent, red, 80 volts, 8-candlepower, 3 to each operating 
 board. 
 
 Lamps, incandescent, green, 45 volts, 8-candlepower, 3 to each operat- 
 ing board. 
 
 Lamps, incandescent, green, 45 volts, 16-candlepower, 3 to each operat- 
 ing board. 
 
 Lamps, incandescent, green, 45 volts, 32-candlepower, 3 to each operat- 
 ing board. 
 
 Lead, for socket alloy, 90 pounds for each 19 mines. 
 
126 SUBMARINE MINING. 
 
 Lead, red, as required. 
 Lead, white, as required. 
 Line, cod, 2,000 feet to each post. 
 Line, measuring, 2,000 feet to each post. 
 Line, sounding, 500 feet to each post. 
 Lye, as required. 
 Marline, 1 pound to each mine. 
 Nails, assorted sizes, 25 pounds to each post. 
 Needles, cleaning, for Khotal lamps, 6 to each post. 
 Nipples, soft rubber, 1 to each hard-rubber fuze can. 
 Oakum, 50 pounds to each post. 
 Oil, cylinder, 5 gallons to each casemate. 
 Oil, dynamo, 1 gallon to each casemate. 
 Oil, lubricating, 1 gallon to each storehouse. 
 Oil, linseed, as required, 3 gallons to 100 pounds of lead. 
 Oil, slushing, 5 gallons to each post. 
 Oil, tar, as required for marline-covered rope. 
 Oil, transformer, 1 gallon to each casemate transformer. 
 Packing, asbestos sheet, 2 pounds to each casemate. 
 Packing, asbestos wick, 1 pound to each casemate. 
 Packings, rubber, 100 to each 19 mines. 
 Paint, acid-resisting, as required. 
 
 Paint, steel color, for casemate apparatus, as required. 
 Paste, soldering, 1 pound to each post. 
 Paraffin, 10 pounds to each post. 
 Pencils, lead, 6 dozen to each post. 
 Plugs, attachment, 6 to each post. 
 Pomade, Putz, 3 pounds to each post. 
 Primers, explosive, 1 to each mine charge. 
 Pumice stone, 2 pounds to each casemate. 
 Resin, 2 pounds to each post. 
 
 Rope, for distance weight, 20 feet for each automatic anchor. 
 Rope for heaving lines, 1,200 feet to each post. 
 Rope for lashings, 1,200 feet to each post. 
 Rope, marline covered, according to project. 
 Rope, raising, 50 per cent more than of mooring rope. 
 Rope, wire-mooring, according to project. 
 Rosettes, 24 to each post. 
 Ruberine, 5 gallons to each post. 
 Sandpaper, 48 sheets to each post. 
 Sapolio, 10 cakes to each post. 
 
 Screws, brass, assorted sizes, 1 gross when required. 
 Screws, iron, assorted sizes, 1 gross when required. 
 Screws, set, for compound plugs, 1 extra set for each compound plug. 
 Screws, set, for mine transformers, 1 extra set for each mine trans- 
 former. 
 
SUBMARINE MINING. 127 
 
 Shellac for insulation purposes, 5 pounds to each post. 
 
 Soap, 25 cakes to each post. 
 
 Sockets, lamp, 12 to each casemate. 
 
 Solder, wire, 5 pounds to each post. 
 
 Staples, large, 20 pounds to each post. 
 
 Staples, small, 1 pound to each post. 
 
 Suspensions, galvanometer, lower, 3 to each insulation testing set. 
 
 Suspensions, galvanometer, upper, 6 to each insulation testing set. 
 
 Tags, brass, 50 per group of 19 mines. 
 
 Tags, lead, 50 per group of 19 mines. 
 
 Tags, linen, 50 per group of 19 mines. 
 
 Tape, protective, 5 pounds to each 19 mines. 
 
 Tape, rubber. 5 pounds to each 19 mines. 
 
 Tinfoil, 1 pound to each 19 mines. 
 
 Towelling, 10 yards to each post. 
 
 Tubes, porcelain, 12 to each post. 
 
 Turpentine, as required. 
 
 Twine, 3 pounds to each 19 mines. 
 
 Varnish, asphaltum, as required. 
 
 Varnish, spar, as required. 
 
 Washers, brass, 100 to each 19 mines. 
 
 Washers, lead, 1 extra set for each compound plug. 
 
 Waste, cotton, 50 pounds to each post. 
 
 Wire, casemate, extra, 100 feet each of black, blue, red, and brown 
 
 to each casemate. 
 
 Wire, fuse, 1 pound each of 3, 12, and 25 ampere to each casemate. 
 Wire, lamp-cord, extra 100 feet to each casemate. 
 Wire, loading, 20 feet to each mine. 
 Wire, soft drawn copper. 
 
 Remarks: 
 
 (a) Clips and thimbles, scales, extension spring, marline- 
 covered rope, and parts for automatic anchors are required 
 only at posts supplied with automatic anchors. 
 
 (&) Loading scoops are required only at posts supplied 
 with trotol. 
 
 (c) In the case of articles to be supplied " as required " 
 it is not contemplated that they shall be kept on hand in 
 larger quantities than required for immediate needs. 
 
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