U.S. War Department

“ 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 forward, if necessary, by means of the cable. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 vaporizer box) so as to get air well out of the pipes. ”

“ 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. ”

“ 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 primary 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. ”

“ 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. ”

“ For the larger cases, the charge should be the maximum 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 cartridges 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. ”

“ 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 slushing oil should be applied in a thin coat, 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, kerosene and lubricating oil, as their presence will cause rusting underneath the slushing oil. ”

“ Large ropes should be stored on skids, allowing a free circulation 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 circulation 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. ”

“ A boat should never go out at night without a good, well-filled lantern. 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 bearings 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 ”

“ 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 battery. 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. [Pg 85]
Direct sunlight should not fall on the cells. ”

“ 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. ”

“ 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 [Pg 78] tank under the engine and forces it into the vaporizer at the proper time. ”

“ The brass collar is screwed on the transformer; a little ruberine on the screw threads facilitates the operation. 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 connecting 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. ”

“ 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. ”

“ 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 3⁄4-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. ”

“ Rowlocks are forked pieces of metal in which the leather of the oars rests while pulling. Swivel rowlocks are movable, 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. ”

“ Man the flywheel and start the flywheel backward, using the weight of the body if necessary, 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 compression, 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. ”

“ 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. ”

“ 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 is 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 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 [Pg 19] testing 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. ”

“ 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 ”

“ In unloading mines charged with dynamite too many precautions 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 usually destroyed. Sometimes the interior of the mine case may be found coated with an extremely thin film of exuded nitroglycerin. ”