CHAPTER II.
PREPARATION OF TORPEDOES.
SERVICE TORPEDO.
=Pattern D.—Plate I.=
=Priming the Service Torpedo.=—Take the torpedo out of its box; remove the screw-cover of the case and take out the wet gun-cotton found in the primer-case; wipe the primer-case dry and insert a primer of 16 one-half inch blocks, or 4 two-inch blocks of dry gun-cotton.
The wet gun-cotton removed from the primer-case is to be put in one of the empty exercise torpedo-cases and dried when opportunity offers.
Wipe the screw-thread carefully and screw down tight the cover on its washer, taking care not to cut it, using the open-end wrench provided for the purpose in the supply-box. _It is absolutely necessary that this case be closed water-tight._
=_Note._=—It is not advisable to prime torpedoes for a much longer time before using than the exigencies of the service require, although experiments at the Torpedo Station show that service gun-cotton torpedoes may remain primed for three months, under service conditions, and yet be relied upon to explode.
=Testing the Detonator.=—Select a detonator, brighten the ends of its legs and attach them to leading-wires. _Put the detonator in a safe place_, connect the leading-wires to the terminals of the testing-magneto and turn the crank. Rattling of the armature will indicate continuity of the circuit and is presumptive evidence that the detonator is good. The wires from the detonator can be taken to the binding-posts T, T of the firing-key of the A machine and tested, a deflection of the needle furnishing proof of continuity (_Plate XVI_); or they can be taken to the terminals of the C machine which will indicate continuity by the striking of its gong. (_Plate XVI_).
=Splicing on the Detonator.= (_Plates I and II._)—The detonator should now be spliced to the spar leading-wires. In splicing on the detonator, so arrange the length of wire that the spherical rubber packing can be placed on the leading-wires five inches from the bottom of the detonator-case, the splices being between the detonator and the packing. Remove the water-cap from the screw-cover of the case. Strip the braiding and rubber tape from the leading-wires for at least six inches from their ends and put on a neat whipping, which shall be outside the packing.
Reeve the ends of the leading-wires through the water-cap and rubber packing. Remove so much of the insulation as may be necessary, for making the splice, from the leading-wires and from the legs of the detonator; brighten the wires and place the insulation of the detonator-legs alongside that of the leading-wires, with the ends of the insulation flush, and expend the bare detonator-legs in turns at right angles around the leading-wires. Turn the ends of the leading-wires back over the splices, and trim off the ends. _One splice should be one-half inch from the detonator and the other one inch from the packing._ Insulate from metallic contact the splice nearest the packing with twine and pass several turns about the wires until the detonator is reached, where the end of the twine is secured. A strip of okonite tape can be used, taking care that the insulation is not too bulky. (See sample splice in supply-box).
=Fuzing the Service Torpedo.= (_Plate I._)—Having lined the holes of the dry blocks with the rectifier, to be found in the supply-box, enter the detonator through the hole in the cover and push it in until the packing is seated; screw up the water-cap hand-tight. Provide the spindle, to be found in Box 53, and secure it to the torpedo-case.
=Shipping the Secondary Spar.= (_Ship‘s._)—Enter the end of the secondary spar in the loop of the outer band, and push in until the key-way is abreast the slot in the loop of the inner band; then put in the key and stop it in.
=Shipping the Service Torpedo.= (_Ship‘s._)—Insert the stem of the spindle in the outer end of the secondary spar and push it home as far as the shoulder. Put in the torpedo-pin and stop it in.
To prevent the strain of towing from starting the splice, turn a cuckold‘s-neck in the spar leading-wires, and lash it to the secondary spar or to the spindle, clear of the torpedo-case. The spar leading-wires should then be led in along the ship‘s spar, abaft the topping lift, and stopped to it at intervals of about four feet.
=Fuzing and Shipping the Service Torpedo, and Shipping the Secondary Spar.= (_Boat‘s._) =Pattern B. Boat-Fittings.=—See that the elevating-arm points aft. Rig in the main spar clear of the guide-ring. Point the inner end of the secondary spar through the guide-ring, the outer end resting on the rail. Reeve the leading-wires through the guide-ring from forward aft, and fuze the torpedo. Then ship the torpedo in the secondary spar, securing it by the torpedo-pin, which must be stopped in. Turn a cuckold‘s-neck in the leading-wires and stop it to the secondary spar or to the spindle, clear of the torpedo-case. Slew the secondary spar in position, butt aft. Reverse the elevating-arm, by revolving it downward, until the guide-ring is in line with the swivel-crutch and heel-rest, carefully tending the inner end of the secondary spar by a line bent on. Ship the secondary spar in the main spar, by rigging the latter out or in, and secure it by a toggle, which must be stopped in.
The boat spar leading-wires are rove through the main spar. To facilitate this, a reeving-line and weight, found in the supply-box, is rove through the main spar, before the secondary spar is shipped; one end of the line is secured to the heel-bolt, and the other around the spar abreast the wire-hole.
When the secondary spar is shipped, bend the end of the leading-wires to the reeving-line, rig out the torpedo until the heel of the spar is conveniently placed for hauling on the after end of the reeving-line, and reeve the leading-wires through the spar, being careful to avoid chafing the insulation.
When the contact spar leading-wires are used they must be rove through the main spar, from aft forward, before fuzing the torpedo.
The spar leading-wires from the heel of the ship‘s spar are taken to the terminals abreast the heel of the spar; from the heel of the boat‘s spar they are taken directly to the C machine, or to the firing-battery, a hand-firing key being interposed when the battery is used. (_See Plate XV._)
_No connection, however, is to be made with terminal, machine, or battery, until the torpedo is submerged and at the proper distance from the side of the ship or boat._
=Testing the Circuit from Ships.=—After the torpedo is submerged the circuit may be tested, to do which connect the spar leading-wires to their proper terminals and connect the binding-screws T, T, of the firing-key, to the proper permanent wires. Place the firing-key as directed for testing the detonator, ship the crank of the D. E. machine, turn rapidly with the sun, and press the key T of the firing-key. A deflection of the compass-needle will indicate that the circuit is complete. (_See Plate XVI._) Or, the testing-magneto may be used to test the circuit.
_The firing-battery must not be used to test the circuit._
=To Fire.=—Make connections with the firing-battery, or with the A machine (_Plate IX_). When using the battery, close the hand-firing key at the moment it is desired to fire. When using the A machine, press the key F of the firing-key, and keep it down; turn the crank of the machine rapidly, and at the instant it is desired to fire, press firmly the key T of the firing-key (the key F being already down).
The Service Torpedo must be immersed 10 feet, and from ships may be safely exploded at 35 feet from the side.
=To Test the Circuit from Boats.=—The spar leading-wires are brought directly to the machine, (_See Plate XVI_), _but not connected until the torpedo is submerged_, when the circuit may be tested by connecting it to the binding-screws of the C machine, turning the crank of the machine and pressing the key T, as for testing the detonator. Or, the testing-magneto may be used to test the circuit.
_The firing-battery must not be used to test the circuit._
=To Fire.=—Make connection with the battery (_Plate XV_), or with the C machine (_Plate XVI_.) When using the battery, close the hand-firing key at the desired instant. When using the C machine, manipulate the keys as directed for the firing-key of the A machine.
The Service Torpedo must be immersed not less than 10 feet, and may be safely exploded at a horizontal distance of 22 feet from the boat.
EXERCISE TORPEDO.
=Pattern D.—Plate II.=
=Priming the Exercise Torpedo.=—Remove the transportation thumb-screw and loosen the thumb-screw on the lug of the hinge. Throw back the cover, replace the second wet block of gun-cotton from the top with a dry 2-inch block, or four ½inch blocks, and put the cover back in place; insert the spindle, to be found in box 53, through the loops on one side and screw down taut against its shoulder; screw down also the thumb-screw on the lug of the hinge. _It is absolutely necessary that this case be closed water-tight._
The wet gun-cotton removed is to be placed in one of the empty exercise torpedo-cases, to be dried when opportunity offers.
=_Note._=—Do not allow the dry primer to remain in the exercise torpedo any considerable length of time before use, as it may absorb enough moisture to prevent detonation.
The detonator is tested and spliced, and the torpedo fuzed in the same manner as directed for the Service Torpedo.
=Shipping the Exercise Torpedo.=—To be done in the same manner as prescribed for the Service Torpedo.
The Exercise Torpedo may be used from either a boat‘s or ship‘s spar. It may be safely exploded at an immersion of 5 feet, and a horizontal distance of 20 feet.
PREPARATION OF THE CONTACT TORPEDO.
=Pattern D.—Plate V.=
=To Convert a Service Torpedo into a Contact Torpedo.=—Attach a circuit-closer, Pattern B, to the frame on the lower head of the torpedo by screws through the lugs.
=Testing the Circuit-Closer.=—Remove the water-cap and spherical rubber packing from the side of the circuit-closer; remove its screw-cover; take out the inner plunger. Remove the braid for a few inches from the longer leg (insulated double-conductor cable) at the outer end of the contact spar leading-wires, whipping the braid. Remove the rubber tape from the conductors, and pass them through the water-cap and packing and through the cylinder of the circuit-closer. Remove the insulation for one inch, brighten and lay up the naked wires and connect them to the binding-posts of the circuit-closer, taking care that the bare ends do not project far beyond the binding-posts. Seat the inner plunger, hauling on the wires at the same time, so as not to leave any slack wire in the cylinder. Set down the water-cap on the packing in the side of the circuit-closer. Replace the diaphragm, friction-plate and screw-cover. Remove the insulation for one inch from the shorter legs at the outer end of the leading-wires, and bend the naked wires together temporarily. Connect the inner ends of the leading-wires with the terminals of the testing-magneto, or of the C machine. Close the safety-break. Remove the safety-pin from the circuit-closer and press down the contact-arms. Under these circumstances a test with the testing-magneto, or with the C machine should show continuity. Release the contact-arms and put in the safety-pin. A test should now show no continuity. After this test the safety-pin must not be removed until just before submerging the torpedo prior to firing.
_It is absolutely necessary that the circuit-closer be closed water-tight._
=Priming the Contact Torpedo.=—Proceed as in priming the Service Torpedo.
=Fuzing and Shipping the Contact Torpedo, and Shipping the Secondary Spar.=—Proceed as with the Service Torpedo, except that the contact spar leading-wires must be rove through the main spar, from aft forward, before fuzing the torpedo. The detonator must be spliced to the short legs of the leading-wires.
=To Test the Circuit.=—The torpedo having been submerged, connect the inner ends of the leading-wires to the testing-magneto, or to the C machine. Close the safety-break and the hand-firing key and test. Under these circumstances continuity should be found.
=To Fire at Will.=—Connect to the firing-battery, close the safety-break and, at the desired moment, close the hand-firing key.
=To Fire on Contact.=—Connect to the firing-battery. Close the safety-break. When contact is made the contact-arms will be forced in, and the torpedo will explode.
=_Note._=—The safety-break should be habitually left open, being closed only just before it is desired to put the circuit in condition to fire by closing either one of the two remaining breaks—that in the hand-firing key, when firing at will, or that in the circuit-closer, when firing on contact.
IMPROVISED TORPEDOES.
Torpedoes may be readily improvised from kegs or casks pitched outside. The fuze should be put in place before filling with powder, in order that it may be near the center of the charge. The spar leading-wires pass out through the close fitting scores in the bung. The latter, after being secured in its place, should be pitched over thoroughly, and weight added to the whole, in order that it may be readily immersed. For exercise torpedoes, bottles, oil-cans, etc., may be used.
An excellent composition for rendering the bung and the entrance of the leading-wires water-tight is made by melting together 8 parts of pitch, 1 of beeswax and 1 of tallow. It is to be applied while fluid.
In order to burn all of the powder in the torpedo, a spindle, to contain the fuze, should be made on board of wood, following the general form of spindle in a gunpowder torpedo, and using a wrapping of cotton cloth, bunting, or paper, to prevent the powder passing through the flame-holes and choking up the spindle.
=Splicing on the Fuze.=—To splice the fuze to the spar leading-wires so arrange the length of wire that the fuze will be entered in the spindle, reaching well into the torpedo-case when the entrance for the wires is closed. The leading-wires must be stripped of covering exterior to the insulation, to a distance extending to just outside the entrance. At this point the outer wrapping on the wires should be secured by a good whipping. If the outer wrapping on the wire is admitted inside, it will, after a time, act so as to introduce water to the charge.
To make the splices, strip the insulation from the leading-wires for about an inch, and brighten them. Brighten the fuze-legs and twist them around the leading-wires in a manner similar to that employed in the Service Torpedo, arranging the splices, however, so that they shall be at equal distances from the top of the fuze. Cut off extra ends and lay the splices in the scores of the fuze-plug; turn the insulator down over them, and secure it with the insulator fastener. (See sample splice in supply-box).
USE OF THE PERMANENT WIRES AND ELECTRIC SWITCHES.
=Connecting.= (_Plate IX._)—The connections with the firing-battery are as follows:—one wire from each switch is connected to one battery terminal, and the common-return wire, with the hand-firing key interposed, is connected to the other battery terminal.
The connections with the firing-key of the A machine are as follows:—one wire from each switch is connected to one binding-post, marked T, of the firing-key, and the common-return wire is connected to the other binding-post of the firing-key, also marked T.
When electric switches are used an intelligent and careful person must be stationed at each switch, the index of which must be kept pointing toward “Battery off; connection through,” except when it is desired to prepare the circuit for firing any torpedo, when the index must be turned so as to point toward the torpedo which is about to be fired.
The circuit for firing any single torpedo may thus be arranged; or, by moving the index to point toward “Battery on both” the circuits will be prepared for firing the two attached to that switch.
By a proper manipulation of the switches the circuits may be prepared so that any one, two, or three, or all four of the torpedoes may be fired simultaneously.
It must be borne in mind, however, that the electric switch is only a commutator for establishing the paths of the currents and that it must not be used as a firing-key.