Chapter V: Offensive Torpedo Warfare (2)

Two cog wheels, a large and a small one, are fixed on the upper part of the after end of the torpedo, just in front of the screw propellers: the small wheel is fitted with a certain number of teeth, thirty for instance, which gears into an endless screw attached to the propeller in such a manner that one revolution of the propeller moves the wheel one tooth, therefore thirty revolutions would turn the wheel one complete revolution. The big wheel is fitted with much larger teeth than the small one, and by means of a pin on the latter wheel is moved round one tooth for every complete revolution of the small wheel, and clamped in this new position by a spring catch, which is also worked by the pin on the small wheel. In front of these wheels is a stud which works fore and aft in a slot, and attached to a spring which tends to draw it to the after end of the slot. This stud is connected by means of a wire rod to the valve that admits the compressed air to the engines; when the stud is in the fore part of the slot the valve is open, and when in the after part it is closed.

_Adjusting Length of Range._--By means of a lever the spring of the stud is compressed, and the stud moved to the fore part of the slot; then the big wheel is moved round until a stud on its face is the required number of teeth above the lever. For every thirty revolutions of the propeller, and consequently one tooth of the big wheel, a certain known distance is traversed, which varies according to the pattern of the torpedo.

_Adjusting Apparatus._--When the propeller has made the number of revolutions corresponding to the length of range required, and consequently has moved the big wheel the number of teeth it was set above the lever, the stud on the big wheel presses against the lever and so releases the spring in the slot, causing the slot stud to fly from the fore part to the after part of the slot, by which action the valve admitting the compressed air to the engines is closed, and consequently the engines cease to work.

Attached to the axle of the big wheel is a small brass arm, which is connected by means of a brass rod to the safety wedge, and is so arranged that after the required number of revolutions of the propeller, the safety wedge will be drawn out; or it may be drawn out at the instant of the torpedo leaving the tube, carriage, &c. Also by means of an additional lever at the fore part of the torpedo, which is connected by means of a wire rod to the valve that admits the air to the engines, and by arranging the attachment of the safety wedge to the brass rod from the big wheel, so that on the wedge being withdrawn it is released from that brass rod, on the torpedo having completed its run, the action of closing the valve which admits the air to the engines causes the additional lever to force the wedge into the safety position.

_Torpedo to Float at End of Run._--This is due to the difference of buoyancy at the end of a run from what it was at the commencement, owing to the compressed air being used in working the engines.

_Torpedo to Sink at End of Run._--This is effected by means of the adjustment chamber (2), in the after end of which there is a spiral spring valve, which can be attached to the brass rod on the outside of the torpedo that works the valve which admits air to the engines, in such a way that on the valve being closed, and therefore the run of the torpedo completed, the spiral spring valve is opened, admitting water to the adjustment chamber (2) of sufficient amount to sink the torpedo.

_To Explode the Torpedo at End of Run._--This is effected by connecting the vertical firing whisker to the rod which otherwise would be connected to the safety wedge lever, by which means, on the valve admitting air to the engines being closed, a force is transmitted to the vertical whisker instead of to the safety wedge lever, and consequently the torpedo is exploded.

_Adjusting the Depth._--A small wheel, the face of which is marked in feet, is placed on the left side of the fore part of the adjustment chamber (2). To adjust for depth, by means of a key turn the wheel until the number corresponding to the depth of run required is opposite the pointer.

The torpedo is maintained at the desired depth by means of certain mechanical apparatus contained within the adjustment chamber (2), and which constitutes what is termed the secret of the fish torpedo. This chamber is connected by screws to the foremost and after chambers of the torpedo, in such a manner that by means of a number of small holes bored round the circumference, as shown at (2), Fig. 119, the faces of the chamber are exposed to the pressure of the water, which varies with the depth to which the torpedo descends. Within the adjustment chamber is an endless strong spiral spring, attached to the after face of the chamber, and so arranged that after being set to a certain tension, capable of resisting an equivalent pressure on the outside of the aforesaid face, any increase or decrease in this exterior pressure will cause the spiral spring to work a rod by which the horizontal rudders of the torpedo are regulated, and thus the desired depth for which the spring is set is maintained. The course of the torpedo is represented by a series of curves, above and below the line, representing the depth it is set for, these curves gradually decreasing until at 100 yards' distance from where the torpedo was started the curves are so small that the path of the torpedo is almost identical to that of a straight line.

Within this adjustment chamber is also placed an automatic balance, which also assists to maintain the torpedo at the desired depth, by reason of its swinging forward on the torpedo descending, and swinging aft on its rising, which motion is used to regulate the horizontal rudders. The above is merely a general idea of the arrangement used in the Whitehead fish torpedo, to enable it to reach and maintain whatever depth it may be necessary to use it at from 5 to 15 feet.

_Projecting the Torpedo._--The fish torpedo may be projected in various ways, viz.:--

1.--Through a submerged tube in the stem, or on the
broadside.

2.--From a carriage above the surface.

3.--From the surface.

_Discharging Torpedo through a Submerged Tube in the Stem._--In this case a tube is fitted to an orifice in the stem; this opening is as far below the water line as possible, and is closed by a watertight cap and a sluice valve; the inner end of the tube is fitted with a watertight door; the torpedo being prepared for action is placed inside the tube, the inner door closed, and the tube filled with water; then the watertight cap and sluice valve are opened, and the torpedo started by means of a piston which is worked by compressed air. This piston can be worked from deck, and so the torpedo fired at the proper instant. To prevent the torpedo from slipping out of the tube, a stop is placed in the fore end of it, which can be withdrawn at the same time as the compressed air is admitted behind the piston. The torpedo being clear of the tube, the sluice valve and watertight cap are closed, and the tube emptied of the water, the projecting piston being at the same time forced back.

_On the Broadside._--In this case, the discharging tube works inside an iron casing, through a stuffing box at the inner end, and in a shield attached to the outer end of the tube. This shield, placed on the fore side of the orifice, is of such a length as to protect the torpedo from the pressure of the water passing the vessel. The mode of discharging the torpedo in this case is similar to that used when projecting it through the stem.

_Comparison of the Stem and Broadside Methods of Projecting the Torpedo._--The former method of projecting the torpedo seems the most suitable to specially built torpedo vessels, but not so to large ironclads, on account of the difficulty of fitting a tube to the stem of such a ship, and also that in so doing the efficiency of the vessel as a ram would be impaired.

In regard to the accuracy of the firing of the above methods, both seem equally good, though in the case of firing on the broadside it would be necessary to prepare carefully calculated tables of deflection, any mistake in the using of which would be fatal to a successful torpedo shot.

_Projecting a Torpedo from above Water._--In this case an iron carriage is used, which is fitted with a frame, in which the torpedo rests; the outer end of this frame is provided with a lip, some few feet long, by which means the rear end of the torpedo is slightly canted up on leaving the frame, and any undue strain on the tail of the torpedo is prevented. The frame is mounted in the iron carriage in such a way that it can be elevated or depressed by means of a screw, as in the case of a gun mounted in an ordinary carriage. The torpedo is ejected from the frame by means of a piston as previously explained, a small reservoir of air being attached to the carriage, so that it can be used at any port.

_Firing a Torpedo from the Surface._--The torpedo possesses sufficient buoyancy to float with a small portion of its upper surface above water; such being the case, it is only necessary to set the various adjustments, point it in the required direction, and by hand turn back the lever on the upper part of the weapon (which opens a communication between the air chamber and the engines), when it will instantly dart off and very rapidly attain the depth it is set for.

_Method of Firing a Fish Torpedo from a Boat._--To manipulate a fish torpedo from a boat, it may be carried in a light frame, which can be lowered or raised by means of a pair of davits. When required to discharge the torpedo, the frame containing it is lowered into the water, so as to bring the torpedo about two feet below the surface, the head being somewhat lower than the tail.

_Thornycroft's Method of Firing Fish Torpedoes from a Boat._--Another method, which has been patented by Mr. J. I. Thornycroft, of the firm of J. I. Thornycroft and Co., steam launch builders, and which is fitted to the torpedo boats built by them for foreign governments, is shown in elevation and plan at Figs. 120 and 121.

The apparatus consists of two or more bent levers _A_ securely and rigidly fixed on a shaft _B_, which works in bearings fixed on the deck of the vessel _C_ from which the torpedo is to be discharged. On the ends of the levers _A_ furthest from the shaft _B_ are pivoted other levers _D_, to which the cradle or case _E_ for sustaining the torpedo is suspended. The other ends of each of these levers are connected to the vessel by means of rods or tubes _F_, jointed at each end in such a way that when the shaft _B_ is made to revolve in its bearings, the case containing the torpedo is guided over the side of the vessel and close to it, and is held in a position convenient for discharging the torpedo, as shown at Fig. 120.

The shaft _B_ may be made to revolve by means of ropes _G_ and pulleys _H_ attached to the levers _A_, or by hydraulic or steam pressure, as may be found most convenient.

The torpedo case can be towed alongside the vessel if necessary without deranging the apparatus. The torpedo case is carried in the angles of the bent levers, and is stowed away so that neither it nor the suspending levers project at all beyond the hull of the vessel; also when lowered, the levers and suspending rods fold over one another so as to occupy very little space, and the torpedo is suspended close to the hull.

Also the torpedo during the operation of lowering as well as when in a firing position remains close to the side of the vessel, thereby obviating any risk or inconvenience from excessive leverage which would have a tendency to capsize the boat.

For especially built torpedo launches, the above mode of carrying and launching the fish torpedo is certainly the best yet devised.

_Woolwich Fish Torpedo._--In the Woolwich torpedo, the engines exert a force of nearly 60 indicated horses, and work up to 1000 revolutions per minute; the total weight of the torpedo fully charged (33 lbs. of gun-cotton) is about 500 lbs.

PLATE XXXVII]

The Whitehead fish torpedo costs about 380_l._, while the Woolwich one costs only 300_l._

_The Lay Torpedo Boat._--Priority of invention of this torpedo was on the 13th of June, 1873, awarded by the Commissioners of Patents to Mr. John Louis Lay, several other persons having claimed the invention, among whom was Colonel Von Scheliha, an officer of the Russian army.

This locomotive torpedo, or more properly called torpedo boat, has been for several years adopted by the American government, during which time it has undergone a series of exhaustive experiments, which has proved it to be a most valuable and efficient weapon of offence and defence. Lately the Russian government have adopted it, and intend using it extensively in the defence of their harbours, &c.

_General Description of the Torpedo._--At Fig. 122 is shown a longitudinal section of a Lay torpedo boat constructed and provided with guiding and controlling apparatus, and with means for propelling it by ammoniacal gas. Fig. 123 is a horizontal section of the same; _A_ is the hull or body of the boat, which has conical ends _A_^{1}, _A_^{2}, and is formed of thin plate iron, or steel, or other suitable material. The section in the end _A_^{1} forms the magazine containing the charge of dynamite or other explosive material; _A_^{3} is the section containing the gas reservoir or holder; the compartment _A_^{4} contains the apparatus for holding and paying out the electric cable; the compartment _A_^{5} in the end _A_^{2} contains the motor engine, the steering apparatus, and other parts to be hereinafter described. All of these compartments or sections are separated from each other by means of air-tight bulkheads _A_^{6}. The torpedo boat may be propelled by means of a single screw, double screw, or two screws. In the latter method, which is shown at Figs. 122 and 123, the propellers _B_ and _C_ are made to revolve in opposite directions; the shaft _D_ of the propeller _B_ is hollow or tubular, and the shaft _E_ of the screw _C_ passes through the same; these screws are actuated by an engine shown at _F._ _H_, _H_ are the horizontal rudders, or side wings, two forward and two aft; these wings are mounted on shafts or spindles passing transversely through the boat; these rudders may be set to occupy a horizontal position, or a more or less inclined position in the proper direction, to cause the submerging of the boat by the action of the water on the said rudders as the boat moves forward, and they are adjusted before starting. _N_, _N_ are two guide rods, one aft and one forward, which project up from the boat to enable the operator to determine its position at any part of its run, and in the case of a night attack they are provided with lights; the said rods can be raised or lowered at the will of the operator. _Q_ is the electric cable, which affords a medium of communication between the operator on shore, &c., and the torpedo boat, whereby it may be started, stopped, steered, fired, and has her position ascertained; this cable is carried in the boat in a coil arranged longitudinally in the air-tight chamber _A_^{4} in the reel frame _R_, and is payed out as the torpedo progresses through a tube _S_, projecting aft under the boat and beyond the rudders and propellers, so that the said cable will not be fouled by the same; or it may be payed out through a hollow shaft in the centre of the boat. One end of this cable is connected to a keyboard at the station on shore or on board of the ship or other structure from which the torpedo boats are controlled. This keyboard is provided with a suitable battery or other means for generating the electric current, as hereinafter described.

The said cable is composed of several wires, each of which is insulated from the others. One of these wires is connected with the mechanism for starting and stopping the boat, one is connected with the steering apparatus, one serves for indicating to the operator at all times the exact position of the rudder, one is connected with mechanism for elevating and depressing the said guide rods, and one serves for firing the charge in the magazine.

The motive power for effecting the necessary movements of the mechanism or apparatus in performing the above operations is obtained from the aforesaid engines, which are provided with suitable valves arranged in combination with electro magnets, shunts, and the devices connected with the said wires of the cable, as hereinafter set forth.

This form of cable has since been replaced by one which consists of two wires only, the one for performing all of the necessary operations, exclusive of the firing or exploding of the magazine, and the other exclusively for this latter purpose. This improvement is effected by employing a series of relays or resistance coils, or a multiple, or compound relay in the boat. The advantages gained by this improved form of cable are:--

1.--Increased flexibility.

2.--A greater length of cable may be coiled in a given
space.

3.--A thicker coat of insulating material may be used,
thereby more perfectly insulating it.

4.--It is much cheaper.

Two rudders are generally used, one below and one above the boat, as shown at _U_, Fig. 122. These rudders are operated and controlled by means of a small auxiliary engine _T_, Fig. 122, which is started, stopped, and reversed by the electric current conducted through the cable _Q_ in connection with magnets attached directly to a valve forming part of the said engine. This valve is so actuated by the magnets that when the current passes in one direction the engine _T_ will move the rudder to starboard, and when the current acts in the opposite direction it will turn the rudder to port.

The mechanism for firing the charge in the magazine _A_^{1} is clearly shown in Fig. 124, and operates as follows:--Projecting from the front extremity or stem of the boat is a rod or pin _V_, which extends through a suitable packing box _W_ into the said magazine or charge chamber; when the boat strikes an object, the said rod is forced inward into contact with the springs or points _X_, thereby closing an electrical circuit and igniting a cartridge, shown at _Y_, in the magazine.

The charge in the magazine can also be fired at any moment by the operator on shore closing a circuit on the keyboard and thereby cutting out one of two resistance coils placed in the circuit to prevent accidental or premature discharge--that is to say, there are two resistance coils. The battery is not sufficiently powerful to fire through both resistance coils at the same time. When the boat strikes an object, the resistance coil in the magazine is cut out by the driving inward of the rod _V_, as above described; the battery then fires through the one on the keyboard. On the other hand, if the operator desires to fire the torpedo boat before she touches the object of attack, he manipulates the switch to cut out the coil in the keyboard, the charge then being fired through the coil in the magazine. This arrangement of the two resistance coils is very effectual in preventing accidents.

In some instances the magazine is made detachable from the hull of the boat, so that on striking an object it will descend or drop down in the water before exploding. This modification is shown at Figs. 125 and 126.

The magazine _A_* is attached at its lower side to the boat by a chain or other suitable connection. At its upper edge it is held by a rod _a_*, as shown in Fig. 125. This rod is fitted to slide in dovetailed bearings, as shown at _b_*, and when this magazine is in its place on the boat the said rod is engaged with a catch or stop _c_*, but when the said rod is driven against any object it is forced back and released from the said catch or stop, and the magazine then drops, as in Fig. 126, and is fired.

To effect the firing a ball _d_* is used and placed in a tube containing two springs or plates _e_* and arranged in an upwardly inclined position, as shown in Fig. 125, one of the said springs being connected with the cable and the other with a wire that passes through the cartridge to earth.

While the magazine is in the position shown in Fig. 125 the circuit is incomplete, but when the magazine drops the said ball falls into the position shown in Fig. 126; the circuit is then completed, and the magazine is fired.

The electrical or electro-magnetic apparatus for generating, directing, and controlling the currents, whereby the above-described operations are effected, may be of any suitable kind, the following being the form of apparatus usually employed.

A battery _r_, shown at Fig. 127, consists of any desired or requisite number of cells constructed and arranged in any suitable manner, and connected by proper conducting wires with the keyboard _s_. The latter is provided with a series of pole changers _s_^{1}, _s_^{2}, _s_^{3}, _s_^{4}, and switches _s_^{5}, _s_^{6}, and is shown in Fig. 128.

Each of these pole changers is arranged to effect and control one of the above-named operations, and is therefore connected with one of the aforesaid insulated wires forming the cable. For instance, the pole changer _s_^{1} effects the starting and stopping of the propelling engine; _s_^{2} controls the steering apparatus; _s_^{3} is connected with the steering index; _s_^{4} operates or adjusts the aforesaid guiding rods; and the switches _s_^{5}, _s_^{6} control and effect the firing of the charge in the magazine.

PLATE XXXVIII]

PLATE XXXIX]

The connections between these pole changers and switches, and the apparatus they operate or control on board the boat, are as follows--that is to say, the said propelling engines have a throttle valve, which controls the admission of the gas from its generator or reservoir to the cylinders of the said engine, and in combination with this valve in the boat there is a shunt and set of electro magnets. The armature of the latter is connected with a lever, which is pivoted so that the action of the electric current in one direction through these magnets will pull one end of the said lever down, and the action of the current in the other direction will pull its other end down--that is to say, by reversing the current through these magnets the movement of the said lever is reversed; and this lever, connected by suitable means with the slide of the said throttle valve, will open or close the same, and thereby start or stop the engine as required.

For operating and controlling the above-described steering apparatus, and indicating the position of the rudder to the operator on shore, the following devices are employed, in combination with the pole changers _s_^{2}, _s_^{3} on the keyboard:--The pole changers are geared together by insulated toothed wheels, which are fixed on the spindles or axes of the said pole changers, so that the latter work accurately together and maintain the same relative positions to each other. The pole changer _s_^{2} is connected by one of the said insulated cable wires with a shunt on board the boat, which shunt is connected with a set of magnets arranged in combination with the valve of the engine that drives the steering apparatus, and which valve is reversed or opened and closed by the reversal of the currents through the said magnets, as above described, and the said engine moves the rudder to port or starboard at the will of the operator. In order that the operator may know the exact position of the rudder at any moment, a series of pins or projections fixed on an arc or other portion of the rudder stock, and arranged in combination with an insulated spring projecting into the path of the said series of pins, are employed. This spring is connected by one of the cable wires with the pole changer _s_^{3} on the keyboard, which is geared with and moves in unison with the pole changer _s_^{2}, so that the electric current that controls the steering engine, and the current that returns the indication of the rudder's position, will both be reversed simultaneously. A separate battery is connected with the index on the said keyboard, whereby a constant current is maintained between this index and the indicating apparatus on the boat.

The current passing from the said spring to the shore is made to indicate the position of the rudder by the index on the keyboard by the contrivance shown in Fig. 129. This contrivance consists of a set of magnets _w_, which have a vibrating armature _w_^{1} pivoted to oscillate between them. One end of the armature lever is provided with insulated spring pawls _w_^{2}, which take into ratchet wheels _w_^{3}. On the same shafts on which these ratchet wheels are fixed are wheels _w_* formed with insulated teeth and geared with each other. The shaft of one of these wheels is geared by bevel pinions _w_^{4} with a vertical shaft _w_^{5}, to which is attached the index needle or finger _x_**, Fig. 128. Therefore it will be obvious that this index finger is placed in connection with the aforesaid spring and series of pins attached to the rudder yoke on board the boat.

Now it will be obvious that when the rudder is turned in either direction these pins will come successively in contact with the said spring, and at each contact and separation the circuit will be made and broken, and an impulse will be transmitted through the cable, whereby a corresponding movement will be transmitted to the said index finger or pointer _x_** on the keyboard.

The pole changer _s_^{4} is connected with another of the insulated wires of the cable, which on board the boat is connected with a shunt and set of magnets arranged in combination with the aforesaid cylinders that operate the said guiding rods, so that by sending the current in one direction the said rods will be raised, and by sending the current in the opposite direction the said rods will be lowered.

The switch _s_^{5} is connected with another of the said insulated wires of the cable, which forms the circuit, including the aforesaid two resistance coils.

By adjusting this switch the operator completes the circuit through the two resistance coils, and then, but not till then, the charge can be exploded, either by the operator, or by the action of the firing pin or rod when the same is driven in and cuts out the other resistance coils as above described. The resistance coil _X_^{1}, Fig. 124, is connected to the binding screws 9, 10 by the wires 7 and 8. These binding screws are in metallic connection with the two springs _X_, but otherwise they are carefully insulated. One pole of the fuze _Y_ is connected to the binding screw 10, the other put to earth through the body of the boat, as at _E_; the main wire 11 is connected to the binding screw 9. Now when the operator cuts out the resistance coil at the firing station, which is done by moving the switch _s_^{6}, the electric current is sufficiently powerful to ignite the fuze _Y_ through the resistance coil _X_^{1}, so that at any moment the torpedo may be exploded by the operator on shore, or by the contact between the torpedo and the attacked vessel the rod _V_ will be driven in, and, coming in contact with the springs _X_, will bridge over the space that originally existed between them and so cut out the resistance coil _X_^{1}, and the torpedo will be exploded automatically.

_Capabilities of the Lay Torpedo Boat._--The capabilities of the Lay torpedo boat are as follows:--

1.--It may be launched from the shore, a vessel,
or a structure, and be kept under observation, and
accurately guided or directed to the ship or other
object to be attacked; and it may be exploded at any
desired moment, or it may be caused to return to the
original point of departure without being fired.

2.--It may be totally and instantaneously submerged to
prevent its destruction or capture by the enemy, and it
may be raised to the surface, as soon as the danger has
passed, in a condition fit for immediate action.

3.--It may be used as a tug or towing boat to take out
a number of torpedoes, which may be sunk and exploded
when desired.

4.--It may be used in connection with certain apparatus
to clear away obstructions found to prevent the
entrance of ships into harbours, and it may also be
used to clear harbours of mines, &c.

_Launching the Lay Torpedo Boat._--For facilitating the launching and controlling of the Lay torpedo boats, a structure or submarine fort is used. This structure may be square, or oblong, and may be made to carry any number of the torpedo boats. The body is constructed of plate or sheet iron of suitable strength and stiffened with angle iron, or otherwise, and divided longitudinally or transversely into watertight compartments, into which the water is admitted to sink the said structure. At the top or upper side, cylinders or tubes are placed, each of which is capable of containing and launching one of the torpedo boats. At the forward end of each tube is a door, or cover secured to a rod or shaft fitted to turn in suitable bearings; this rod or shaft is provided with an arm which is connected to the piston rod of an engine worked by gas contained in a reservoir, or by other suitable means. The slide or other valve which controls the admission of the gas, &c., to this engine is arranged in connection with electro magnets, connected by a suitable cable with a keyboard on shore, or wherever the operator's station may be. By sending an electric current through this cable in one direction through the electro magnets, the door is closed; and by sending such a current in the opposite direction it is opened. The cables carried in the torpedo boats, and through which the mechanism on board each torpedo boat is operated and controlled, are also in this case connected with the keyboard, which must be provided with a number of sets of pole changers and switches, or equivalent devices, corresponding with the number of boats to be controlled by means of the said keyboard.

This apparatus will form a very convenient adjunct to fortifications or stations liable to be attacked by sea. The said fort may be prepared for use by placing torpedo boats in the said tubes, and may be kept floating until the enemy's ships have arrived closely enough to permit the determination of the point where the said fort can be most advantageously located for operating against the said ships. The fort is then towed to this point, or taken as near as possible thereto on rails, and towed the remainder of the distance. It is then submerged, and will be ready for immediate operation. The said fort is provided with suitable valves for the admission of water to sink the same, and with means for forcing in air through the pipe _P_* to expel the water when the fort is to be raised.

When it is desired to launch either of the said torpedo boats, the door of its tube or cylinder is first opened by sending a current through the cable that controls the door, as above described. Then the current is sent through the boat's cable to start her propelling engines. The said boat will then emerge from the cylinder or tube and will rise to the surface, or as near the surface as may be desired, and may then be directed and controlled by the operator at the keyboard, as previously described. And one after another of the said torpedo boats may be thus launched and exploded, without giving to the enemy any clue to the point or position from which they are being sent.

PLATE XL]

_Launching the Torpedo from a Ship._--The method of launching the Lay torpedo boat from an ironclad or other large ship is shown at Fig. 130. The tubes or cylinders _S_ in which the torpedo boats _A_ are held are, in the apparatus shown at Fig. 130, closed at their inner ends by plates, or covers _S_^{1}, which are provided with suitable water-tight and insulating packing boxes _S_^{2} for the passage of the electric cables of the said torpedo boats, each cable being connected with the keyboard, which is placed in any convenient part of the ship, and at their outer ends the said tubes are furnished with strong and well-fitted slide valves, or sluice gates _S_^{3}, which are opened by screws, connected by gearing with a hand wheel, and shaft _S_^{4}, _S_^{5}, for the admission and exit of the said torpedo boats. Also these cylinders are provided with packing pieces at their sides, arranged to be pressed by screws or otherwise up to the sides of the torpedo boats in these cylinders, and thereby hold them firmly and immovably in rough weather.

_The Method of Sinking and Raising a Lay Torpedo Boat._--The apparatus by which this is effected is shown at Fig. 131, which is a longitudinal section of a portion of a torpedo boat. The hull _A_ of the torpedo boat is provided with a water chamber _l_, which has holes or apertures _l_^{1} in the bottom of the same, and is also provided with an air cock at _l_^{2}. In connection with this chamber is arranged a small cylinder _m_, provided with a piston _m_^{1}, whose rod _m_^{2} is attached to the lever of the said cock. A spiral spring _m_^{3} is provided to resist the inward movement of the said piston. The said small cylinder _m_ is connected by a pipe _m_^{4} with a valve chest, in which is arranged a slide valve _m_^{5}. The said slide valve is connected by a rod or rods to the lever or levers _m_^{6}, whose fulcrum is at _m_*, and the said levers are connected by the links or rods _m_^{7} with the armatures of electro magnets _n_, which are included in the circuit of the cable, whereby the boat is controlled from the keyboard at the station; _o_ is a pipe extending from the said valve chest to the aforesaid water chamber _l_; _p_ is a feed pipe by which gas is conducted from the reservoir or generator to the valve chamber.

When it is desired to sink the torpedo boat an electric current is sent in one direction through the said magnets, and thereby operates the slide valve to admit gas to the cylinder _m_ in front of the piston _m_^{1}, which is thus forced inward and opens the air cock _l_^{2}. The opening of this cock permits the escape of the air from the water chamber _l_, and consequently the entrance of water through the apertures _l_^{1}, and the boat then immediately sinks.

When it is desired to raise the boat a current is sent in the opposite direction through the said electro magnets, thereby operating the said valve and piston in such a manner as to close the cock _l_^{2} and open the port _o_^{1} and the pipe _o_, thereby allowing the gas to pass from the valve chamber into the compartment _l_; this gas by its pressure expels the water from the said compartment, and the boat then having its normal buoyancy restored immediately rises to the surface.

_The Lay Torpedo Boat used as a Tug to take out a Number of Small Torpedoes._--This arrangement is shown at Figs. 132 and 133. The small vessels or torpedoes are designed to be first sunk and then exploded, chiefly for clearing harbour or the like of mines or other obstructions. These results are accomplished by means of the following devices and arrangements, that is to say, each of the small vessels or torpedoes _F_ is provided with apparatus which is included in an electrical circuit formed by a suitable insulated cable _G_, extending throughout the train of small vessels or torpedoes _F_. One vessel of this train, preferably the rear one, is connected with the station by an electrical cable _H_, which is payed out from a coil or coils, or a reel or reels, in the said vessel as the same travels through the water. This cable _H_ connects with the cable _G_, which is connected with the towing boat _A_, and passes through the series of boats _F_ to the said cable _H_. One wire of the said cable is arranged in combination with sealed or covered apertures in the bottom of a compartment or compartments of these small vessels _F_, as shown at _I_, the covers of these apertures being so formed as to be ruptured or destroyed by the explosion of a cartridge or cartridges placed in the said compartment or compartments. When a current of electricity is sent through the aforesaid wire of the cable it will explode the said cartridges and open the apertures, thereby admitting water into the said compartments so that the vessel _F_ will sink.

The cable _G_ that passes through the train of torpedoes or vessels _F_ is so arranged that when a current passes through the other wire of the said cable it will fire cartridges placed in the charge chambers or magazines of the said small vessels, as shown at _J_. The part of the cable or towing line _G_, which connects the towing boat _A_ with the train of small boats or torpedoes _F_, is attached to a hook or other device, which can be disengaged by sending a current through the cable _K_, connecting the boat _A_ with the shore or other station. It will be understood that when being used for this purpose the said boat _A_ is not or need not be charged with explosive material.

PLATE XLI]

The aforesaid towing boat _A_ takes the train of torpedoes _F_ to any required position. It is then disengaged from the train, leaving the said small vessels or torpedoes _F_ floating in such position. Then by sending a current first through one wire of the cable _H_ the boats _F_ are first sunk by the explosion of the cartridges and opening of the apertures, as above described. They may then be discharged immediately by sending a current through the other wire of said cable _H_ and firing the cartridges in their magazines, or they may be left submerged to form mines which may be exploded at any desired moment.

The said small vessels or torpedoes may be provided with vertical rods to indicate their position to the operator at the station; these rods are shown at _L_, and they should be made hollow to allow the air in the water compartments or chambers to escape to permit the water to enter the same when the vessels _F_ are to be sunk; or other suitable provision may be made for the escape of the air from these compartments.

The said vessels _F_ are preferably made cylindrical with conical ends, and are provided with suitable insulating and water-tight packing boxes, as shown at _F_^{1} for the cable _G_ to pass through at the stem and stern of each vessel.

_The Lay Torpedo in Clearing Obstructions._--For this purpose the torpedo boat is provided with an apparatus, shown at Figs. 134 and 135, in combination with the electric cable, whereby the said boat is controlled and guided, and there is arranged in the boat _A_ a compartment _A_^{3}, from which extends down into the water a line or rod _U_, provided at its outer end with a hook or claw _U_^{1}, properly formed to take hold of any chain or bar with which it may come in contact. In the said compartment _A_^{3}, and upon the upper end of the said line or rod _U_, is placed a small case or cylinder _U_^{2} containing a charge of dynamite or other explosive material and a cartridge or fulminating cap, or a bottle of sulphuric acid, surrounded with a certain quantity of chlorate of potash and sugar. This case or cylinder _U_^{2} is shown detached and drawn to an enlarged scale at Fig. 135, and it will be seen that the said case is provided with a tube 1 containing a cartridge, or a phial filled with explosive substance at 2, and a ball or weight at 3. The said case is fitted to slide upon the said line or rod _U_, and when placed at the upper end thereof and not held or retained will slide to the lower end of the same. In the said compartment _A_^{3} is arranged at _U_^{4} an electro-magnetic apparatus, included in the circuit of the said cable, and connected with a bolt or catch which in its normal position holds the said explosive case and prevents its running down on the grappling line or rod _U_. This explosive case is also provided at its lower end with a grappling hook _U_^{5}.

When the grappling hook _U_^{1}, on the lower or outer end of the line or rod _U_, engages with any obstruction the boat will be stopped, and this stoppage will be indicated on the keyboard. The operator by this indication is apprised of the stoppage of the boat by an obstruction, and by sending a current through the cable by means of a switch provided for this purpose on the keyboard he can immediately release the explosive case _U_^{2}, which runs down the line or rod _U_, and engages by its grappling hook _U_^{5} with the hook _U_^{1}. The line or rod _U_ is then disengaged from the boat _A_, and the explosive case _U_^{2} turns or falls over. As it turns over the ball or weight 3 contained in the tube 1 drops on the said phial 2, fractures it, and thereby allows the acid to mix with the explosive or fulminating charge and explode the case _U_^{2}. This explosion will rupture or destroy the obstructing chain or bar, so that the ironclad ships or other vessels can pass freely and safely into the harbour or beyond the point where it was intended to stop them.

_Used to clear away Mines and Electric Cables._--For this purpose there is an implement _V_ provided, Fig. 136, somewhat of an anchor form, but with four or any desired number of arms _V_^{2} extending outward at a suitable angle from its shank _V_^{1}. In the neck of each of these arms are fitted two small plain or toothed discs _V_^{3}, which are so arranged as to present their teeth to any object lying in the angle or corner formed by and between the arms _V_^{2} and shank _V_^{1} of the said implement, as shown at _W_.

In using this implement it may be attached to a line or cable coiled in the torpedo boat, which, in this case, is used without being charged with explosive material, and is sent in advance of any ship that has to enter or pass through the suspected water. This line must be arranged in combination with a detaching apparatus controlled by electro-magnetic apparatus included in the circuit of the cable which connects the torpedo boat with the keyboard at the operating station.

PLATE XLII]

By sending a current from the station the operator releases the said implement or its line from the detaching hook or holding device. The said implement then sinks to the bottom; then the said boat returns to the ship, paying out the said line as she so returns. The end of this line is then taken by a steam tug or other vessel, and the said grappling implement is thereby dragged along through the water over which the ships are to advance, thus breaking any wires or cables that may be in its course. This operation is shown at Fig. 137, in which _A_ is the towing boat, _K_ the controlling cable, _V_ the said implement, _V_* the line attached to the implement _V_, _X_ _X_ submerged mines, and _X_^{1} _X_^{1} are the mine cables.

In some instances it may not be practicable to reach the enemy's ship or other object of attack directly from the station to which the torpedo boat is connected, and from which it is controlled. In this case a small boat, &c., is used in addition, which should be so arranged as to present to the enemy's view as slight a surface as possible. This mode of attack is shown at Fig. 138, where _A_ is the torpedo boat, and _N_ is the small auxiliary boat. This boat _N_ is provided with a keyboard and battery like that described at page 144, and the electric cable _L_, carried on and payed out from the torpedo boat _A_, is connected with the keyboard. The boat _N_ is also attached to and towed by the torpedo boat _A_ by the tow line _O_; and the torpedo boat is steered and guided by means of the said keyboard in the boat _N_. The auxiliary boat is designed to contain two men, who lie down, one at the bow, the other in any convenient position abaft him; the latter has control of the keyboard, while the former by the aid of a telescope keeps the torpedo boat in view, and transmits his orders to the man at the keyboard. On arriving at such a distance from the enemy as to render an attack practicable, the tow line _O_ is disengaged, and the torpedo boat _A_, guided and controlled, and fired from the boat _N_. The torpedo boat being exploded, the auxiliary boat can be rowed back to the station or ship to which it belongs. By this means the range of action of the torpedo boat is greatly extended, and with comparatively slight danger to those employed in making the attack.

A more recent form of the Lay torpedo boat is shown at Figs. 139, 140, and 141, where Fig. 139 is a plan or top view of such a boat, Fig. 140 is a side elevation of the same, and Fig. 141 is a midship section on the line _x x_. _A_ is the hull of the boat, _a_ is the main or central portion of the said hull, _b_, _b_ are side or auxiliary portions of the same. These parts _a_ and _b_ may be oval or circular in transverse section; they are constructed of thin steel or other suitable sheet metal, and secured together by riveting or bolting. The side or auxiliary portion _b_ form the reservoirs or chambers for the gas; they also serve to contain the propelling engines. _c_ is the magazine, _d_ the chamber or compartment for containing the coiled cable, _e_ is the compartment containing the electrical steering and other apparatus, _f_ is the firing rod or pin, _g_ is the water ballast chamber, _h_ is the cable, _i_ the paying-out tube, _j_, _j_ are the screws or propellers which rotate in opposite directions, and _k_, _k_ are the sight or guiding rods.

The parts of the apparatus or mechanism whereby the various operations of the torpedo boat are effected are connected to the cable and controlled by electric currents transmitted from the station through the cable, as previously described. The Lay torpedo boat weighs about 1 ton, its length is 23 feet, and speed 12 knots per hour.

_Spar or Outrigger Torpedo._--By a spar or outrigger torpedo is meant a torpedo which is carried at the end of a pole or spar projecting from a boat or vessel, and which may be fired either by contact or at will.

This system of submarine offence has up to the present time been the only one that has successfully stood the crucial test of actual warfare.

During the civil war in America the spar torpedo attack was resorted to by the Confederates and Federals, principally by the former, the result being the loss of two large men of war and severe injury to several other ships composing the Federal fleet, and the loss of one vessel of war belonging to the Southerners.

The spar torpedo was also used on several occasions by the Russians in their attacks on the Turkish ships in the war of 1877-8, but in only one attempt was it the means of sinking a Turkish vessel.

_Description of McEvoy's Duplex Spar Torpedo._--At Fig. 142 is shown a sketch of Captain McEvoy's improved patent duplex spar torpedo, which is the form most generally used at the present time, and which seems to fulfil all the requirements of such a submarine weapon, viz.:--

1.--Handiness, at the same time capable of containing a
charge of gun-cotton sufficient in contact to destroy
the most powerful vessel afloat.

2.--Certainty of action.

3.--Capable of being fired either on contact or at will.

4.--Mode of attaching the spar simple and very secure.

PLATE XLIII]

In Fig. 142, _a_ is the case, capable of containing some 33 lbs. of gun-cotton; _b_ is the tube through which the three wires _w_, _w_^{1}, and _w_^{2} are led; _c_ is the socket in which the wooden or steel spar is introduced and secured, _d_ is the striker, which is attached to a brass contact plate within the head of the case _a_ in such a manner that any pressure either on the head or side of the striker _d_ will force the aforesaid plate in contact with the two studs to which the battery wires are attached; _e_ is a cradle affixed to the striker _d_ to ensure its action on contact being made by the torpedo with the attacked vessel; the explosive is inserted at _f_, the socket _c_ being made to screw on and off.

When a hollow steel spar is used, the battery wires are sometimes led through the interior of the torpedo and the spar, by which means they are well protected; the only objection to this method of leading the wires being the probability of injury to them, should the spar be broken on contact, or by a shot.

_McEvoy's Arrangement of Torpedo Wires._--At Fig. 143 is shown the arrangement of wires as devised by Captain McEvoy, whereby the spar torpedo may be exploded at will or on contact. _c_ and _z_ are the poles of the firing battery, to which are attached respectively the wires _d_ and _d_^{2}; _f_ is the fuze, which is placed in the centre of the charge, and to the poles of which the wire _d_^{2} is attached, the other end of this wire being connected with the stud _s_; to the stud _s_^{1} is attached the other end of the wire _d_, and at the point _c_ in the same wire is inserted a contact breaker; another wire _d_^{1} is connected to the wires _d_ and _d_^{2} at the points _r_ and _r_^{2} respectively, and at the point _k_ in this same wire is inserted a firing key, which latter is shown in section at Fig. 144, from which the mode of connecting the two ends of the wires and of using the key will be at once apparent. The contact breaker is somewhat similar to the firing key, but there is no spring in it, contact being made or broken by screwing the two parts together or apart. The object of the contact breaker is to prevent the torpedo being exploded by contact, and so to place the control of the weapon entirely in the hands of the operator. As will be seen from Fig. 143, if contact is broken at _c_, it is impossible to fire the torpedo unless the firing key _k_ be pressed in; but should contact be made at _c_, then either by means of the firing key _k_, or by the torpedo striking the hostile vessel, its ignition will be effected.

The foregoing method of arranging the spar torpedo wires is certainly very neat and effective, and is at the present time in extensive use. As yet it has not been adopted by the English government, they still preferring to fire the spar torpedo at will alone.

The different methods of manipulating the spar torpedo from boats will be described in the following chapter.