FOOTNOTES:

[J] 'Electricity and Magnetism,' by Professor F. Jenkins.

[K] See Appendix.

[L] As constructed by Mr. J. Mathieson, late R.E., at the Silvertown Telegraph Works, Essex.

CHAPTER V.
OFFENSIVE TORPEDO WARFARE.

THE term "Torpedo" is applicable more particularly to offensive submarine mines than to those employed for the purposes of defence, and therefore by torpedoes will be understood every kind of submarine explosive weapon designed to be used for active attack against vessels, &c., no matter how they may be manipulated.

Offensive Torpedo Warfare still in its Infancy.—Though during the seventeen or eighteen years that torpedoes have been considered as a legitimate mode of naval warfare there have occurred three big wars, in each of which submarine weapons, offensive and defensive, have played an important part, still the subject of offensive torpedo warfare must be even now considered as in its infancy, and therefore any opinions expressed as to the merits and demerits of the various apparatus in connection therewith can but be based on the theoretical capabilities of each torpedo, and on the results of experiments carried out with them during peace time, which latter as a rule are conducted under far too favourable conditions to be relied upon.

Their Use during the Civil War in America.—During the American civil war, the only offensive submarine weapon that was used was the outrigger or spar torpedo, which in those days was a crude and imperfect machine, and manœuvred from boats possessing all the features which a torpedo boat should not possess. Still under these unfavourable conditions ships were sunk by such means by both Federals and Confederates, proving that in future wars this mode of attack, favoured by the vast and important improvements that have lately been effected both in connection with the torpedoes and torpedo boats, should play a prominent part, and prove a most destructive mode of attack.

Their Use in the Franco-German and Russo-Turkish Wars.—In the Franco-German war of 1870-1, offensive torpedo warfare was not resorted to by either side, the French fleet being deterred from entering German waters by the submarine mines placed, or at least supposed to be placed, in position.

From the Russo-Turkish war much light was expected by torpedoists to be thrown on the subject of torpedo warfare, but alas, little or nothing was done to settle any of the many vexed questions which exist in regard to offensive submarine weapons. The torpedo experience of that struggle tended rather to prove that the vast importance hitherto attached to torpedo attack was much exaggerated.

One of the causes which led to the failure of offensive submarine weapons, when employed on active service, seems to be due to the fact that, owing to the extremely small radius of the destructive effect of such weapons, it is absolutely necessary for complete success to explode the mine in actual contact with the attacked vessel; to ensure which, at night time, in an unknown harbour, with the position of the vessel attacked somewhat uncertain, and even without the additional obstacles of guard boats, booms, electric lights, &c., is a service of infinite difficulty, and one which may easily terminate in a failure. The foregoing would more especially apply to the spar torpedo attack, but in an attack with the Whitehead fish, or towing torpedo, there would be an additional cause of failure, viz., the complicated nature of their manipulation.

Torpedoes may be divided into four classes, viz.:—

Drifting or Floating Torpedoes.—By "drifting" or "floating" torpedoes are meant all those submarine machines which are dependent on the tide or current of a stream for their action and motion.

During the American civil war this mode of attacking vessels was constantly employed by the Confederates, and though not successful in destroying any of the Federal ships, was the means of considerably hampering the movements of their river flotillas.

Drifting torpedoes might be advantageously used for the destruction of pontoon bridges, booms, &c., and in this way, had the Turks in their late war used them, the Russians would have found the crossing of the Danube a matter of infinite danger and difficulty; in fact, by a systematic use of such weapons, combined with a little dash on the part of the Ottoman flotilla on the Danube, that river should have been to the Russians an impassable barrier. To use these torpedoes most effectively, especially against a single vessel, a thorough knowledge of the force and direction of currents should be gained before proceeding to undertake an operation in which these submarine weapons are used.

Another point to be remembered is, that if such a torpedo were started with the flood, for example, towards an enemy, and did not explode, there would be a chance of its being returned to the starting-place by the ebb tide.

In this class the following torpedoes seem the most practicable:—

Description of Lewis's Drifting Torpedo.—"Lewis's" drifting torpedo, designed for the express purpose of destroying booms or other floating obstructions placed round a vessel at anchor for the purposes of defence, is shown at [Fig. 101]. It consists of a box a, containing the charge and fitted with several detonating fuzes. This box is attached to one side of a beam b, and within 6 inches of one extremity, the beam being about 20 feet long and 7 inches square; to the opposite side, of the same end of the beam b a heavy weight c, resting in a shoe d, is attached by a long iron rod e, which reaches to the other extremity of the beam, and is there connected to a bell-crank lever and spring f, a pressure on which detaches the weight c; a chain g, 18 feet long, connects the weight loosely with the upper end of the beam, and another chain h, 9 feet 6 inches long, connects it with a point more than 2 feet below the centre of the beam. The apparatus is so constructed that it floats nearly vertical with the top of the beam just above the surface of the water.

On the machine drifting against the boom or other obstruction, the spring or lever f at the upper extremity is pressed down, thus releasing the weight c, which falling, becomes suspended by the two chains g and h, and brings the beam into an inclined position. The weight of this mass of iron and the chain suspending it are suddenly brought to bear on the top of the beam, dragging it under water and clear of the boom, &c. At the same time the lower end, released from the weight, rises, and the whole apparatus is carried forward by the current against the side of the vessel, on striking which the torpedo is exploded.

Description of McEvoy's Drifting Torpedo.—"McEvoy's" drifting torpedo is intended to be floated, singly or in groups, by the aid of tides or currents against vessels at anchor, bridges, &c.

At [Fig. 102] is shown a plan of this form of drifting torpedo.

It consists of the body of the torpedo a, which contains the charge, at the side of which is placed the loading hole b; c is the tube containing the priming charge; d is the framework surrounding and protecting the wheel or screw e; f is the fuze pillar, in the centre of which is a steel rod g, and on the top a thin steel plate h is placed; i is the nipple for the percussion cap; k is a horizontal bar, turning and resting on top of the fuze pillar f; m is the lever for supporting the hammer n when it is set; l is the screw barrel supporting the wheel or screw e; o is a safety pin; q is the supporting chain, and p the spring for working the hammer n.

By means of a buoy or log of wood, from which the torpedo is suspended, it can be adjusted so that the explosion shall occur at the requisite depth.

To prepare the torpedo for use, unscrew the fuze pillar f, take off the horizontal bar k, place a percussion cup on the nipple i, and screw it tightly against the end of the steel rod g. The fuze pillar is then ready for use, and should be screwed into the body a. Then fill the torpedo with the explosive and close the loading hole b. The hammer n is then set by drawing it back and bringing the end of the lever m against it, at the same time running the screw barrel l under the lever m, so that its end catches the screw of the barrel, as shown in the figure. The safety pin o is then put in its place and secured by a few parts of thread, which by a sharp jerk on the safety line will be easily broken.

[DRIFTING TORPEDOES.]

The horizontal lever k, which carries the lever m and propeller e, rotates on the top of the fuze pillar f, and is prevented from rising by means of a screw. The torpedo being let go, the safety pin o is pulled out by means of a line which is attached to it. The propeller will not revolve whilst the torpedo is drifting with the current, but the instant it is stopped by the action of the current the wheel will be caused to revolve, and after a few revolutions it will unscrew the barrel from under the end of the lever k, and the latter, dropping the hammer n, will be forced by the spring p into contact with the thin steel plate h on the top of the fuze pillar, which blow is transmitted by means of the steel rod g to the percussion cap, and the torpedo exploded.

American Extempore Drifting Torpedo.—This form of drifting torpedo, which is readily made, was used in great numbers by the Confederates, and though not successful in sinking any Federal ships, caused their vessels considerable annoyance and delay.

At [Fig. 103] is shown a sketch of this torpedo. It consists of a tin case containing about 70 lbs. of powder. A stiff wire a, b passes through a hole punctured in a strip of tin c, and a stuffing box d; the end a of the wire is covered with fulminate, and so arranged that the friction caused by its passage through the strip of tin c will ignite it; a number of wires lead from b to pieces of driftwood on the surface e, e, e, and the case is supported at the proper depth by a line attached to a section of log.

Towing Torpedoes.—By towing torpedoes are meant those submarine machines which are so shaped and arranged, that when towed from a ship or boat in motion they will diverge to a considerable extent, thus enabling the towing vessel to pass clear of the ship attacked, and yet near enough to allow of the torpedo being brought in contact with some part or other of her hull.

Towing torpedoes were for the first time employed on actual service during the late Russo-Turkish war, when a modified form of the well-known Harvey torpedo, designed by a German officer, was used by the Russians, but in no case was it successful.

In this class of submarine offensive machines may be placed the following:—

Harvey's Torpedo.—This form of towing torpedo was invented conjointly by Captain John Harvey and Commander Frederick Harvey, R.N., and is intended to be used at sea both as a means of offence and defence.

At [Fig. 104] is shown in elevation the small sized Harvey towing torpedo, in which all the latest improvements that have been devised are represented.

a is the case of the torpedo, formed of Muntz's metal, but not provided, as the original ones were, with an exterior case of wood; by this alteration greater capacity combined with extreme lightness is obtained, which undoubtedly much enhances the value of the small size torpedo which is intended to be carried by and manœuvred from boats; b is the principal or after lever, hinged on the top of torpedo at c, and rests, when ready for action, in a crutch formed in the top of the exploding bolt d; e is the foremost lever, hinged at f, and kept in position on the after lever b by a groove formed in it and a lashing which passes through a slot in the principal lever, as at g; h is the side lever, pivoted at i, and exerting a pressure on the firing bolt d by means of a lanyard which is passed through the bolt k and over the principal lever b; l is the top lever, pivoted at m, and exerting a pressure on the bolt d by means of a lanyard which is passed through the bolt n and over the principal lever b; this top lever l has been added to ensure the action of the torpedo, on its striking sideways against a vessel; o and t are handles, to the former of which the lashings of the levers h and l are secured; p is the ring used for attaching the buoy rope; r, r are two loading holes, made in the side of the torpedo case, by which a charge of gun-cotton may be quickly and efficiently stowed; this also is a new feature in the small size torpedo; s is the rudder formed for the purpose of controlling the direction of the torpedo when the tow line is suddenly slacked.

In regard to the large size torpedo, the construction of the case remains as in the original ones, the improvements being, the enlargement of the loading and fuze holes, and the addition of the top lever l, as shown at [Fig. 104].

The small size torpedo is capable of holding 47 lbs. of water, whilst the large size one will contain 76 lbs. of water, or about 33 lbs. and 58 lbs. of gun-cotton respectively.

The slings are made of best Italian hemp, and consist of a span of four legs, which are secured to lugs at the corners of the torpedo and connected to an iron thimble, which is shown at Fig. 105; this thimble is made suitable for either wire or hemp rope, and is so arranged that should the seizing become slack, the parts of the slings cannot become detached from the thimble.

[HARVEY'S TOWING TORPEDO.]

The legs of the slings should be so fitted that when stretched alongside the torpedo they extend 1 foot beyond the stem for the large torpedo and 8 inches for the small one; the four legs should be so fitted that when an equal strain is brought on them, the thimble should be on a level with the upper lugs, and the upper fore span form an angle of 80° to 85° with the side of the torpedo; this is shown at [Fig. 106]. This arrangement gives the best divergence with the least strain on the tow rope, and is suitable when the torpedo is kept at short scope, as well as when a long length of tow line is out.

The mode of attaching the foremost and side levers is shown at [Fig. 107]. Before reeving the lanyards they should be well greased in the wake of the fair leads, but not where they are made fast. The lanyards should be made up like a reef point. Care should be taken that the short arm of the side lever h is brought close into the fair lead, and its lanyard should be set up sufficiently taut to give a slight spring in the principal lever b by the strain thus brought on it. This lever b has a steel fish on the top, in order to prevent it taking a permanent bend. If the side lever lanyard is properly set up, the bolt will spring down about 1/8th of an inch when the safety key is withdrawn, owing to the spring in the lever, and the shrinking of the lanyard; this brings the muzzle 1/8th of an inch nearer the pin without disturbing the side lever.

The bolt is so arranged that the torpedo can be fired by either of the following methods:—

Mechanically.—In this case the bottom of the inner cylinder, as at a, [Fig. 108], is fitted with the ordinary mechanical chemical fuze, ignition being effected by the breaking of the glass vessel containing the sulphuric acid on being forced into contact with the needle n, by the action of the levers on the torpedo striking a vessel.

Electrically at Will.—For this purpose a platinum wire fuze is used, one terminal being connected to earth through the bolt, the other to a wire leading up through the core of the bolt, and connected by means of an ebonite joint with a single cored electrical cable leading from the torpedo vessel.

Electrically on Contact, or at Will.—In this case, a resistance coil is inserted in addition to the fuze, and is so arranged that on the bolt being forced down a short circuit is formed, cutting out the resistance coil (about 20 ohms), and thus enabling the battery to fire the fuze, which, owing to the 20 ohms resistance in the circuit, it was previously unable to effect. Should the bolt so arranged be required to be fired at will, it is only necessary to put a more powerful battery in circuit, and so fire the fuze through the 20 ohms resistance.

Exploding Bolt.—The exploding bolt is fitted to act with a pressure of from 30 to 40 lbs. on its head for the large size torpedo, and from 15 to 20 lbs. for the small size one.

The bolts are all the same size, and differ only in the direction of the slot for the safety key k, being port or starboard bolts accordingly. The muzzle of the exploding bolt stands 1 inch off the pin when in the safety position, that is, when the safety key rests on the brass work of the priming case.

The safety key is secured in the slot of the exploding bolt, as shown at [Fig. 108], by eight or nine parts of strong whitey-brown thread secured to the key, passed round the bolt, and securely knotted; the parts of the thread should come away with the key, in order that none of the parts may be worked down the tube by the exploding bolt.

In the event of the large torpedo being cut away in deep water after the withdrawal of the safety key, it will explode by pressure on the head of the bolt at about sixty fathoms depth; the small one at about thirty fathoms.

Buoys.—The buoys are of two sizes, and are made of solid cork (such cork only being used as will ensure great floating power after being immersed for a time); each buoy is built upon a galvanised iron tube running longitudinally through; on the ends of the tube are screwed wooden cones, which bind all together, and render the buoy indestructible.

Two buoys are used for each torpedo, the larger buoys for the large size torpedo, and the smaller buoys for the small size torpedo. The buoy rope is of hemp, about five or six fathoms in length and two inches in circumference, an eye being spliced in the end nearest the torpedo; to this eye is bent the tow rope, with a single or double sheet bend forming the knot by which the torpedo is towed; the other end of the buoy rope is passed through one of the rings in the stern end of the torpedo (according to whether working in deep or shallow water), then through the tube of the first buoy, and an overhand knot made in the rear; then through the next buoy, and a knot in the rear of that. Recently, Captain Harvey has adopted a large and a small buoy for each torpedo, the large one being practically sufficient, the smaller one being added in the event of the other one becoming sodden.

Brakes.—The brakes are used for the purpose of controlling the tow ropes; they can be fixed by screws into the deck at the most convenient place for command, and in a properly constructed torpedo vessel would be placed below the water line, to prevent exposure of the men working them. They are so arranged as to admit of the tow rope being quickly veered, and at the same time are sufficiently powerful to bring the torpedo to the surface when required. Success greatly depends on the skilful handling of these brakes, for in conjunction with the cork buoys they give the operator command of the depth at which the enemy is to be struck. Unless a very high rate of speed is required, one handspike will control the tow rope; the other strap can be thrown off the drum, and the handspike allowed to lie on the deck ready to be thrown into gear, if necessary. The surface of the drum in contact with the strap should be powdered with rosin to increase the friction. The tow rope should be so reeled up that in veering the reel may revolve towards the men at the handspike. The spindle will contain several tow ropes, that, in the event of one torpedo being cut away, another can be immediately bent.

The brake for small torpedo requires only one drum and handspike. It can be fitted to a steam launch by placing an extra thwart across near one of the others.

Care should be taken that the riding turns lie fairly over each other, to prevent a jamb when veering.

The brakes, both large and small, are so made as to ensure durability, they being considered a part of the ship's furniture.

Brake for safety key line is a small reel on the same principle. When going a slow speed, it may not be necessary, as the safety key line can be attended by hand; but when going ten or eleven knots, it will be found of considerable advantage, both in keeping the bight of the safety key line from dragging astern, thereby lessening the divergence of the torpedo, and also in drawing the safety key when a strong stop is used.

Arrangements for Launching and Towing the Torpedoes.—A yard across either the main or mizen mast of a torpedo vessel, from 20 to 25 feet above the water line, is a very convenient method for launching and towing. The leading block on the yard, through which the tow rope is rove, may be fitted to a traveller on the yard with an inhaul and outhaul, that the distance out from the ship's side may be regulated as convenient.

In a large vessel, the leading block for tow rope can be fixed to the end of the quarter-boat's davits. The brakes for commanding the tow rope should be screwed firmly to the deck. In a vessel properly constructed for the service, they would be on the lower deck, the tow rope having been led along the yard, and down each side of the mast.

A leading block for the tow rope is placed on the deck by span or bolt a few feet in front of the brake. The safety key reel, if used, must be fixed in a convenient position on deck, that the man attending it can see how to control it; in a properly constructed vessel he would be in the pilot house. The safety key line leads through a small leading block on the ensign staff or some convenient point abaft the lead of the tow rope, 15 to 20 feet above the water. The leading block on the yard may be fitted with a lizard, if thought necessary. A sharp instrument should be kept by the brakes ready to sever the tow rope.

In large men of war, arrangements are made for carrying a loaded torpedo and two buoys in a convenient position on each side of the vessel, in such a manner that the tow line can be bent, the exploding bolt screwed in, the levers adjusted, and the torpedoes and buoys dropped simultaneously when required.

Preparing the Torpedoes for Use.—The torpedoes, port and starboard, loaded and ballasted, having been hoisted out of the torpedo room, are placed on the deck on their own sides, with their heads forward under the leading block, and the buoys placed abaft them and strung together; the exploding bolts are now entered into the torpedoes, and forced down until their safety keys rest on the brass work, taking care that each safety key points in the direction of the eye through which its lanyard has to pass; the levers are now secured by their lanyards, as explained at pages 120 and 121. The eye at the end of the buoy rope is now rove through the large or small ring in the stern end of the torpedo. The tow rope having been previously rove through the leading block on the deck and on the yard, is rove through the thimble of the slings from forward aft, and bent, with a single or double sheet bend, to the eye of the buoy rope. The safety key line having been previously rove through the leading block on the ensign staff, and the lanyard on the safety key having been led through the eye of the handle, making a fair lead with the slit in the bolt, are bent together with a double sheet bend, and stopped to the eye of the handle by a split yarn of suitable strength, the yarn having been first secured to the line by a round turn outside the bend.

The line should also be stopped with another split yarn round all parts of the slings close up to the thimble, having first made an overhand knot in the line at a distance a few inches longer than that between the eye bolt and the thimble.

The crew having been stationed at their respective posts, the handles having been shipped on the tow reel, the tow line is then reeled up until the torpedo will launch clear, and swing out under the leading block on the yard. Hold the torpedo by the handspikes, and take off the handles of the brake. In swinging out, care should be taken that in starting from the deck the fore slings do not foul the fore top lever. The stern of the torpedo can be steadied by keeping a slight strain on the buoy rope. The safety key line must be kept clear, and not checked, or it might break the stop and draw out the key before intended. The buoys must be placed in a proper position and hands stationed by them to launch them overboard the instant the torpedo takes the water. It would be better to stop the screw, if circumstances would allow of it, when lowering the torpedo and buoys into the water, to prevent the chance of the buoys fouling the screw. The torpedo, on reaching the water, will immediately diverge clear of the ship; the buoys being launched, as the strain comes on the buoy rope, they will be towed clear away from the screw, and full speed may be put on at once. The men at the handspikes must veer steadily, occasionally checking the torpedo, that it may be kept near the surface, and not allowed to dive, which it will do if the tow rope is slacked up altogether, and then a sudden strain brought on it.

Eventually it will come to the surface, when the bow is pointed up by the strain on the tow rope; greater the speed the more quickly will it be brought to the surface. In shallow water this should be particularly attended to, as in diving it might strike the bottom and injure the levers, and, if the safety key has been withdrawn, explode; moreover, it brings an undue strain on the tow rope. The torpedo can now be gradually veered out to the distance required, the safety key line so attended that a sufficient strain is kept on it as not to allow of a long bight of line dragging astern of the torpedo; at the same time having due regard to the strength of the yarn by which the line is stopped to the handle of the torpedo. The distance veered must depend upon the nature of attack. The tow line should be marked with knots every 10 fathoms: under some circumstances the torpedo would be close to the ship until passing the enemy; at other times veered to 40 fathoms it will be found most suitable.

The full divergence of 45° is obtained up to 50 fathoms; beyond that the bight of the tow rope in the water drags the torpedo astern, unless the tow rope is triced much higher up, which has its disadvantage; 40 to 50 fathoms of tow rope gives the best command of the torpedo, veering 2 or 3 fathoms of tow line suddenly will always sink the torpedo some feet below the surface. Should it become necessary to use the torpedoes with a stern board, they can be so used, but in this case the port torpedo is used on the starboard, bow and starboard on the port; all other arrangements being exactly the same. In rough weather, advantage should be taken of the roll, and the torpedo allowed to swing out from the yard, and be let go by the run, checking the tow rope immediately the torpedo is in the water. It is not absolutely necessary to ease the vessel when launching; the torpedo can be launched at full speed. In the event of its being found necessary to cut adrift the torpedo, in consequence of coming suddenly across a friendly vessel, the tow rope should be cut near the brake, and if the buoy rope has been rove through the large stern ring, the torpedo will sink and be lost, the buoy only remaining. If the buoy rope has been rove through the small stern ring, the torpedo will be suspended by the buoy rope; and should the safety key not have been withdrawn, can be recovered with safety.

In the event of wishing to recover it when the buoy rope has been rove through the large ring, a toggle must be lashed on the tow rope abaft the leading block on the yard, when it can be recovered by the buoy rope; as a general rule, however, it will be found best to expend the torpedo, and not attempt its recovery.

HARVEY'S TOWING TORPEDO.

SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.

Recovering the Torpedo.—Should the safety key have been withdrawn, great caution is necessary. Tongs, shown at [Fig. 109], for going round the upper part of the bolt, to take the place of the safety key, when once clasped and secured round the bolt, render the torpedo safe to handle; this could only be done from a boat. With the safety key in, there is no danger in hoisting it inboard again by its own tow rope, and hoisting up the buoys at the same time with a grapnel.

Different Methods of Using the Torpedo.—There are two methods of employing the torpedo, either of which may be adopted, according to circumstances.

1.—When it is towed with a length of line varying from 25 to 60 fathoms, and dipped when in position to strike the attacked vessel.

2.—When it is kept suspended from the yard, &c., and dropped at the spot, where according to the first method it would have been dipped.

In the first method, it is not necessary to withdraw the safety key till just before dipping; in the second method the safety key line is belayed at about twenty fathoms, and the key withdrawn when the line is tautened by the ship going ahead.

Tactics.—Description of the various attacks that may be made with the Harvey torpedo against a ship at anchor or under way. In the following diagrams T is the torpedo vessel, S the ship attacked.

Attacking a Vessel moored Head and Stern.—In this case the torpedo vessel steers in for the bow or quarter of the vessel attacked, according to the direction of the current, and on the side approached launches the torpedo between the moorings, as at A; leaving the tow rope slack, the torpedo vessel proceeds ahead or astern against the current, and when at a sufficient distance off, the tow rope is held fast, which will cause the torpedo to diverge into contact with the vessel attacked, as shown by [Fig. 110].

Attacking a Vessel at Anchor by Crossing her Bow.—In this case the torpedo is sufficiently diverged when near to the vessel with a good scope of tow rope out. After having crossed her bow, proceeding onwards, the tow rope will be brought obliquely across her cable, and the torpedo will swing into her, as shown at [Fig. 111]. It may be here remarked, that in all cases the depth of the explosion can be obtained by the sudden slacking of the tow rope; and the tow rope once under the keel, causes the torpedo to be hauled down near to it before exploding.

Attacking a Vessel at Anchor by coming up from Astern on either Side.—In this case the torpedo is launched when on the quarter of the vessel attacked, as at A, the tow rope left slack. After steaming ahead some distance, hold fast the tow rope, when, by continuing to steam on, the torpedo will diverge into contact with the bottom of the vessel attacked, as shown at [Fig. 112]. When skilfully performed, the total destruction of the enemy is certain, since the torpedo is springing from a depth to the surface, and will, in consequence, strike near her keel. The torpedo vessel can pass at her greatest speed, and, if thought necessary, near enough to clear away any of the ordinary obstructions, such as booms, nets, &c.

Passing Down between Two Lines of Vessels at Anchor.—In this case it would be impossible to fire at the torpedo vessel, for fear of injury to their friends. Two or more torpedo vessels following each other with preconcerted signals would cause great destruction. See [Fig. 113].

Attacking a Vessel in Motion from Right Ahead.—In this case two torpedoes are launched, port and starboard, each diverging to its full extent; when passing the vessel attacked, one or the other of the tow ropes is brought across the cut-water, and by the simultaneous motion of the two vessels in opposite directions, the torpedo is brought alongside of or under the bottom of the vessel attacked, as shown at [Fig. 114]. The torpedo vessel should keep the masts of her enemy in one until close to, when either torpedo will be used, according to the movement of the enemy. At the time of the tow rope taking the cut-water, the brake is suddenly eased up; the tow rope will then pass under the bottom, when by checking the tow rope the torpedo will be hauled under the bottom.

To execute this attack, judgment, skill, and nerve of the highest order will be required, as the risk of being run down will be imminent.

The Attack from Astern.—In this case two torpedoes are launched, and diverged as in the previous case; it is assumed in this instance that the torpedo vessel can outspeed the vessel attacked, which will enable her to bring a torpedo under the run of the attacked vessel, as shown at [Fig. 115].

SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.

If Chased by a Hostile Vessel, and unable to Face her.—In this case veer a torpedo astern, having first obtained a position a little on the bow of the chasing vessel. When it is known by the length of the tow rope out that the torpedo is about abreast of her bow, hold fast the tow rope, which will cause the torpedo to diverge, and be brought into contact, as shown at [Fig. 116]. As a last resort drop spanned torpedoes.

Torpedoes can be used with a stern board, if necessary. The port torpedo, in this case, will be launched on the starboard side, and the starboard on the port side.

It should be here remarked that, although great speed is essential in the torpedo vessel to come up with the enemy and choose an advantageous position, it is not advisable to tow the torpedoes, if it can be avoided, at a greater speed than 11 knots; because the strain brought upon the towing gear is excessive, and the torpedo would require a large addition of ballast to keep it sufficiently immersed to attain the full divergence.

There is, however, one style of attack in which the highest speed can be maintained, viz. by dropping the torpedo alongside in passing.

This mode of attack is one of the best, particularly under cover of darkness, against a ship at anchor.

The position of the torpedo is known, and the tow line is never in contact with the enemy during the operation; a skilled hand at the brakes is all that is required, the vessel keeping a straight course at the highest speed, passing as close as possible to the enemy, in order to clear away all obstructions. The tow rope must not be checked by the brake too suddenly.

Defensive Purposes.—The Harvey torpedo may be used as a means of defence by large ships against a torpedo vessel attacking with that species of submarine weapon, as the latter would be forced to pass outside the former vessel's torpedo, and thus decrease the chance of a successful dip. Again, in the case of an attack by the ram, these torpedoes afford some protection, as a deterrent.

Night time.—Though a dark night and tempestuous are favourable to a surprise, yet in the case of a Harvey torpedo attack it is essential that the weapon should be seen to dip it at the proper time, therefore daylight is necessary to this species of torpedo attack.

Value of the Harvey Torpedo.—The Harvey torpedo is undoubtedly of considerable value when ably handled, yet the skill and judgment required is very great, and can only be acquired by constant practice.

Description of the Menzing Towing Torpedo.—This modified form of the Harvey towing torpedo was designed by Captain Menzing, of the German navy, to remedy what is considered by the Germans as the chief defect of that weapon, viz. its liability to injure friendly vessels, and also to do away with the necessity of using two torpedoes, one for each side of a ship.

At [Fig. 117] is shown a plan and elevation of this towing torpedo. a is the body of the torpedo, somewhat similar to the Harvey, but narrower at the stern, and bevelled on both sides towards the bow; b is an iron frame placed in the bow, capable of being turned either to the right or left; c is the hole for the introduction of the fuze, and d is the loading hole; e is a rudder placed at the stern of the torpedo; f, f are levers, by pressure against which the torpedo may be fired mechanically, or electrically at will; these levers are connected to a block of wood fitted with stops to prevent them being pushed too far over; s and p are two towing ropes, one on each side of the torpedo, which pass from its stern through the point of the frame b, and thence to the vessel, these are also connected to the rudder e in such a manner that on either of the ropes s and p being tautened the rudder e is turned in the opposite direction; w is an electric cable, strong enough to bear the whole pressure of the torpedo when being towed right aft.

To diverge the torpedo on the starboard quarter of the ship, the line s must be slackened, and the whole towing strain brought on the rope p, causing the frame b to be pulled over to a knot k in the rope p, made at the proper position to ensure the torpedo towing at the correct angle from the course of the vessel, and at the same time causing the rudder e to be turned to starboard; this is shown at [Fig. 117] by the dotted lines.

To diverge the torpedo on the port quarter, the towing rope p would be slackened and the whole strain brought on the rope s, and an action opposite to that already described would be the result.

Two cork buoys are used, similar to those employed with the Harvey torpedo; one being attached at a distance of 10 feet from the stern of the torpedo, and the other at such a distance astern that the torpedo would be placed at a distance below the surface to allow of safety to a friendly vessel.

GERMAN AND FRENCH TOWING TORPEDOES.

The torpedo is manipulated in a similar manner to the Harvey, the circuit being closed at the moment of the first buoy disappearing, at which time the torpedo would be about ten feet below the surface. The two buoys are together capable of supporting the torpedo, and thus by means of the second one it may be picked up, should it be necessary to cut the towing ropes.

Description of the French Towing Torpedo.—The towing torpedo used by the French is represented in section and plan at [Fig. 118].

a is the body of the torpedo, formed of wood enclosed in a thin steel case; b is the head made of cork; c is the case containing the charge, which is generally 33 lbs. of dynamite, this case is supported by the bolt d resting on the plate e; f, f are whiskers, which are connected to the plate e; g and h are hollow tubes, one end of g being attached to the case e, and one end of h to the rear end of the body of the torpedo a, and they are so arranged that when the case c is released, its weight will draw out the tube g, which slides along the tube h to nearly the full extent of the latter; k, k are bolts, to which the towing sling is attached; l is the fuze, and n is a small gun used for firing the torpedo at will. The hole in the plate e through which the bolt d passes is larger than the latter, so that when the plate is moved backwards by pressure being applied to the whiskers the bolt is freed from support, and case c attached to it falls.

The modes of firing are as follows:—

1.—The automatic plan of firing is effected by the tube h, after it has fallen a certain distance, corresponding to a depth of 9 feet for the case c, drawing down by means of a line attached to it a plug contained in the body a, which completes the circuit of the firing battery.

2.—The plan of releasing the charge at will is effected by means of the small gun n, which is fired by electricity, and by its firing forces back the plate e, thus releasing the charge, which is then exploded, as previously explained.

Locomotive Torpedoes.—By "Locomotive" torpedoes are meant those that possess within themselves the power to move through the water, when once started in a given direction.

Of this species of submarine weapons, the following are the most efficient and are the ones most generally used:—

Invention and Adoption of the Fish Torpedo.—The idea developed by the fish torpedo is due to an Austrian marine artillery officer, who is now dead. In 1864, Mr. Robert Whitehead, then superintendent of iron works at Fiume, acting upon the suggestions of a Captain Lupuis of the Austrian army, commenced a series of experiments to ascertain the practical value of the above idea, the result being a fish torpedo, commonly called "The Whitehead," which though far inferior to the fish torpedo of the present day, was then considered to be a fearful and wonderful weapon.

The Austrians were the first to purchase this weapon, and two years later, in 1870, Mr. Whitehead came to England, and prosecuted numerous experiments with his fish torpedo under the supervision of several English officers, and on the 8th of October of the same year he succeeded in completely destroying an old hulk moored at the mouth of the Medway. The fairly successful results of these experiments induced the English government to purchase the secret and several of Mr. Whitehead's fish torpedoes, under the following conditions:—

1.—The right of manufacturing them in England.

2.—To be kept fully informed of all improvements, as soon as made.

3.—The right of using all such improvements.

And the total amount paid to Mr. K. Whitehead at that time was the sum of seventeen thousand five hundred pounds, which did not include the sum of two thousand five hundred pounds claimed for the expenses attendant on the Medway experiments. Since then a large number of Whitehead's fish torpedoes have been purchased from time to time, especially during the Turco-Russian war, when some two hundred were ordered, also great numbers have been manufactured at Woolwich. The English fish torpedo, as far as can be ascertained, is a vastly superior weapon to the Whitehead fish torpedo, possessing as it does increased speed, and therefore far greater accuracy.

Besides Austria and England, nearly all the European governments have purchased the Whitehead secret and torpedoes, but in the case of some of them, the last two clauses of the English conditions of purchase were omitted.

WHITEHEAD'S FISH TORPEDO.

The Turkish is the only government that has obtained the Whitehead secret and torpedoes without paying for it. This was managed as follows:—

"On the night of the 20th of December, 1877, the Russians made an attack with Whitehead torpedoes on an Ottoman squadron lying in the harbour of Batoum, but owing to a want of practical knowledge of the manipulation of such weapons, no vessels were sunk or damaged, but two fish torpedoes, one in perfect condition, were found the next morning high and dry on the beach at that place."

The American government have up to the present time not sanctioned the purchase of the costly Whitehead torpedo, preferring their own locomotive torpedo, which will be fully described further on. On a government purchasing the fish torpedo, a certain number of their naval or military officers are sent to Fiume in Austria, where Mr. R. Whitehead's manufactories are situated, and where the necessary very exhaustive experiments with his torpedoes are carried out, and are there thoroughly instructed in the manipulation of these machines, and are also supplied with a double set of drawings of the various parts of the torpedo. These officers, and all others whom it may be necessary to initiate into the mysteries of the Whitehead secret, are bound on their honour not to divulge it.

Employment of Fish Torpedoes in War.—The fish torpedo has been employed on actual service on three known occasions only, in two of which it failed to fulfil its deadly mission.

On the 29th of May, 1877, a Whitehead fish torpedo was fired by H.M.S. Shah against the Peruvian ironclad Huascar, but failed to strike her, owing to the latter vessel altering her course at the moment of the torpedo being discharged. The next instance of the employment of the Whitehead torpedo was that one mentioned at [page 132]. The last and only successful attempt yet made occurred on the 26th of January, 1878, when the Russian steamer Constantine fired a Whitehead torpedo against a Turkish guard vessel off the harbour of Batoum, and completely destroyed her.

Description of Torpedo.—A general view of the Whitehead fish torpedo is shown at [Fig. 119]. It is divided into three parts, connected together by screws.

1.—The charge chamber.

2.—The adjustment chamber, in which is placed what is known as the secret.

3.—The air and engine chamber.

Vertical and horizontal steel fins are fitted for the purpose of maintaining the torpedo in an upright position whilst passing through the discharge tube, or frame; the former fins run nearly the whole length of the weapon, while the latter are considerably shorter. The motive power of the torpedo is compressed air, forced by means of a powerful steam air compressing pump into a portion of the steel chamber (3) at a tension of upwards of 1000 pounds to the square inch, which is equivalent to about sixty atmospheres, and which by means of a set of small three cylinder Brotherhood engines, contained in the steel chamber (3), drives two screw propellers. These engines are capable of exerting a force of forty indicated horses, and yet only weigh about thirty-five pounds, from which it will be understood that to attain these results the workmanship and materials employed in their manufacture are of the very highest order and fineness.

The torpedo is made of various sizes, ranging from 14' long and 14" maximum diameter to 19' long and 16" maximum diameter.

Capabilities of the Fish Torpedo.—The capabilities of the fish torpedo are as follows:—

1.—If adjusted for a certain depth, from 5 to 15 feet, and projected from above water, or if started from the surface, or if discharged from a submerged tube, it will rapidly attain that depth, and maintain it during the run.

2.—If fired in still water, it will make a straight run in the line of projection, provided that an allowance has been made for the deflection due to transverse currents.

3.—It can be adjusted to stop after having run any distance up to its extreme range, and after stopping to sink, float, or explode.

4.—Its range and speed vary considerably, according to the pattern of the torpedo.

Whitehead Fish Torpedo.Woolwich Fish Torpedo.
Yards.14' long, 16" max. diam. one screw.14' long, 16" max. diam. two screws.14' long, 14" max. diam. two screws.14·5' long, 14" max. diam. two screws.
200....20 knots.25-1/4 knots.
2509-1/2 knots.......
300..12-1/4 knots.19-1/4 knots.24-1/2 knots.
4008 knots...18 knots.23 knots.
600..11 knots...20 knots.
750..10-1/2 knots.....
8007 knots...16-1/2 knots.18 knots.
1000..9 knots...15-1/2 knots.

Pressure of air in engines varies for distance and speed from 40 atmospheres to 140 atmospheres.

Placing the Charge.—The explosive is generally placed in what is termed the cartridge case, which case is similar in shape to the interior of the charge chamber (1), and is fixed thereto by means of wooden wedges.

Ignition.—The method of ignition is mechanical, and is arranged as follows:—Extending from the nose of the torpedo to the cartridge case is a tube terminating in a copper case, in which is placed the priming charge and detonating composition; within this tube is a steel rod some 2 feet long, fitted with a needle point at its inner end, and its outer end screwed into a frame; this frame is capable of moving in and out, and is connected with a spiral spring which tends to force it, and consequently the steel rod, or striker, inwards. By compressing this spiral spring, the inner end of the frame is butted against a catch, by which it is prevented from acting. On this catch being released, no matter by what means, the spring is brought into action and forces the frame and steel striker inwards, the needle point of the latter coming into contact with the detonator fires the priming charge, and so explodes the torpedo. The foremost extremity of the torpedo, which is termed the nose piece, is so fitted that it is capable of being forced inwards, but in a position of rest its inner edge is just clear of the catch. On a pressure being brought on the nose piece in a direct line with the length of the torpedo, it will be forced inwards, the result being the releasing of the catch and explosion of the torpedo. In addition to the nose piece, horizontal and vertical levers, or whiskers, may also be used, a slight pressure on either of which will similarly effect the explosion of the torpedo; also cutters for penetrating nets, &c., are fitted to the nose piece when desired.

Safety Wedge and Key.—For safety purposes a wedge is employed, which when in the safety position prevents the catch from acting; this wedge is so arranged that it may be withdrawn by the action of the machinery after the torpedo has run a certain distance, and also may be replaced by similar means in the safety position on the completion of the run. As an additional precaution a safety key is used, which is inserted in the head of the torpedo through the spring of the frame.

Description of Adjustment Apparatus.—For adjusting the length of range for withdrawing and replacing the safety wedge, &c., the following apparatus is employed.

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 [Fig. 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.

THORNICROFT'S BOAT APPARATUS FOR FISH TORPEDOES.

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

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 A1, A2, and is formed of thin plate iron, or steel, or other suitable material. The section in the end A1 forms the magazine containing the charge of dynamite or other explosive material; A3 is the section containing the gas reservoir or holder; the compartment A4 contains the apparatus for holding and paying out the electric cable; the compartment A5 in the end A2 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 A6. 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 [Fig. 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 A4 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 A1 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 [Fig. 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 s1, s2, s3, s4, and switches s5, s6, 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 s1 effects the starting and stopping of the propelling engine; s2 controls the steering apparatus; s3 is connected with the steering index; s4 operates or adjusts the aforesaid guiding rods; and the switches s5, s6 control and effect the firing of the charge in the magazine.

[LAY'S LOCOMOTIVE TORPEDO.]

LAY'S LOCOMOTIVE TORPEDO.

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 s2, s3 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 s2 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 s3 on the keyboard, which is geared with and moves in unison with the pole changer s2, 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 w1 pivoted to oscillate between them. One end of the armature lever is provided with insulated spring pawls w2, which take into ratchet wheels w3. 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 w4 with a vertical shaft w5, 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 s4 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 s5 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 X1, [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 s6, the electric current is sufficiently powerful to ignite the fuze Y through the resistance coil X1, 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 X1, 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.

LAY'S LOCOMOTIVE TORPEDO.

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 S1, which are provided with suitable water-tight and insulating packing boxes S2 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 S3, which are opened by screws, connected by gearing with a hand wheel, and shaft S4, S5, 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 l1 in the bottom of the same, and is also provided with an air cock at l2. In connection with this chamber is arranged a small cylinder m, provided with a piston m1, whose rod m2 is attached to the lever of the said cock. A spiral spring m3 is provided to resist the inward movement of the said piston. The said small cylinder m is connected by a pipe m4 with a valve chest, in which is arranged a slide valve m5. The said slide valve is connected by a rod or rods to the lever or levers m6, whose fulcrum is at m*, and the said levers are connected by the links or rods m7 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 m1, which is thus forced inward and opens the air cock l2. 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 l1, 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 l2 and open the port o1 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 [Fig. 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.

[LAY'S LOCOMOTIVE TORPEDO.]

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 F1 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 [Fig. 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 A3, from which extends down into the water a line or rod U, provided at its outer end with a hook or claw U1, properly formed to take hold of any chain or bar with which it may come in contact. In the said compartment A3, and upon the upper end of the said line or rod U, is placed a small case or cylinder U2 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 U2 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 A3 is arranged at U4 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 U5.

When the grappling hook U1, 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 U2, which runs down the line or rod U, and engages by its grappling hook U5 with the hook U1. The line or rod U is then disengaged from the boat A, and the explosive case U2 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 U2. 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 V2 extending outward at a suitable angle from its shank V1. In the neck of each of these arms are fitted two small plain or toothed discs V3, which are so arranged as to present their teeth to any object lying in the angle or corner formed by and between the arms V2 and shank V1 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.

[LAY'S LOCOMOTIVE TORPEDO.]

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 X1 X1 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.

[LAY'S LOCOMOTIVE TORPEDO.]

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, w1, and w2 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 d2; f is the fuze, which is placed in the centre of the charge, and to the poles of which the wire d2 is attached, the other end of this wire being connected with the stud s; to the stud s1 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 d1 is connected to the wires d and d2 at the points r and r2 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.

General Remarks on Offensive Torpedoes.—The torpedoes that have been described in this chapter are the only ones that at the present time can be considered as having been proved to be practically useful, and which in future wars may be employed against ships with some chance of success.

The spar, the Whitehead fish, and the Harvey towing torpedo have each been subjected to the test of actual service, the former weapon being the only one that has under those conditions been successfully used. Taking this fact into consideration, also the high pitch of excellence that has been attained in the construction of steam torpedo boats, and also the results of the numerous exhaustive experiments that have been from time to time carried out in England, America, and Europe, with various modifications of the locomotive, towing, and spar torpedoes, there can be no two opinions as to which of the numerous species of offensive submarine weapons is the most practicable and effective, and that is the spar or outrigger torpedo.

To manipulate successfully locomotive and towing torpedoes in an attack against hostile vessels, the operators must be not only unusually fearless and self-possessed, but also must possess a thorough practical knowledge of the complicated method of working and manœuvring those weapons—in fact, they must be specialists; whilst in the case of the spar torpedo, which may be fired by contact, it is only necessary to employ men capable of handling a boat well, and possessed of dash and pluck, to ensure an attack by such means being generally successful. Of course under some circumstances, such as in a general action, when the locomotive and towing torpedoes are manipulated from specially constructed torpedo vessels, they will prove of great value, and the fish torpedo fired from a boat, in close proximity to the attacked vessel, in smooth water, and unmolested, would sink a vessel which under the same circumstances, owing to her being protected by booms, might prove impregnable to a spar torpedo attack; but such favourable conditions will not often occur in war time.

[Mc. EVOY'S DUPLEX SPAR TORPEDO.]

As an offensive submarine weapon of defence, the Lay torpedo boat should prove of real value; and also manœuvred from specially constructed vessels, it seems capable of being used in a variety of ways. As yet little is known of this weapon, all the experiments carried out with it having been confined to America; but now that Russia has adopted it, and one or two have also been secured by the Peruvians, its practical value will become more generally known.

CHAPTER VI.
TORPEDO VESSELS, BOATS, AND SUBMARINE BOATS.

EMPLOYMENT of Torpedo Ships.—Torpedo ships, that is to say, sea-going vessels, very fast, handy and impregnable, specially designed to carry and operate offensive submarine weapons, such as locomotive, towing, and the spar torpedoes, especially the former, are now considered as a necessary and valuable adjunct to a fleet, their special work being to give the coup de grâce to disabled ironclads in a general action; they will also be used to attack the ships of a blockading force, and against rival torpedo vessels. As a general rule these torpedo ships will be armed with the ram and torpedoes only, heavy guns being dispensed with, though the Nordenfelt and other machine guns will be considered necessary.

The German Torpedo Vessel Uhlan.—This torpedo vessel was built in Germany by the Stettin Engine Company, and launched in 1876.

She is armed with a contact torpedo charged with dynamite carried on a 10-foot ram, lying deeply under the water line. To protect the vessel from the effects of the discharge of the torpedo, she is built with two complete parts, sliding one within the other, and having a considerable extent of intermediate space between them. This space is filled with a tough and elastic material (cork and marine glue), which even in the case of the bows being carried away, would afford a second line of resistance. The Uhlan carries an engine of one thousand indicated horse power. The steam is supplied by Belleville's tubular generator. These engines occupy by far the greater space of the vessel, only a very small portion being left for her crew and coal. This great power of the engines is necessitated by the fact that she has to be driven at a very high speed, at the same time she has a very great draught, also the greatest facility of steering has to be attained; hence the proportion of width to length, 25 to 70 feet. In order to save the crew at the worst, a raft is constructed, which is also filled with a mixture of cork and marine glue, and is placed near the helm. The mode of operating with the Uhlan is as follows:—

The dynamite torpedo is affixed to the point of the ram by the aid of divers. The rudder is then fixed, and the crew opening a wide port on the vessel's side, jump on the aforesaid raft. The steamer then rushes forward, and explodes its torpedo in contact with the hostile vessel. The crew hold on to the torpedo ship, and in case she is not injured board her again and repeat the manœuvre, if necessary.[M]

This is a novel form of torpedo boat, but does not seem to be a very practicable method of torpedo attack.

Admiral Porter's Torpedo Ship Alarm.—The Alarm torpedo ship was built from plans designed by Admiral David D. Porter, U.S.N. Her total length, which includes a ram 32 feet long, is 172 feet; her beam is 27 feet 6 inches, and her draught of water is 11 feet. She is built of iron on the bracket plate system, that is to say, she has a double hull, one shell being constructed inside the other. Her double bottom is divided into a number of water-tight compartments. The whole interior of the vessel is also built in compartments, which may be hermetically closed, so that in case of both the shells being ruptured, it would still be impossible to fill the entire ship with water. She is steered by the same apparatus which propels her, viz. the Fowler wheel, which is illustrated at [Fig. 145].

This wheel turns on a vertical shaft, and its paddles are feathered by an eccentric cam in such a manner that at one part of their revolution they have a pushing and drawing action on the water, while at another part they present only their edges. In fact it is simply a feathering paddle wheel, turned horizontally instead of vertically. By suitably turning the cam wheel, which is done from the helm, the feathering of the paddles is caused to occur at different points; and in this way the vessel may be turned, or rather her stern twisted around, as if on a pivot. At the same time, by suitably adjusting the paddles, the ship goes ahead, or astern, the engine meanwhile running in the same direction.

By the apparatus above described it is considered that the Alarm is afforded not only a means of speed, but of being handled with the utmost readiness, which latter is absolutely essential in such a vessel, as she must always meet her antagonist bows on.

The steering is accomplished from the wheel house located aft on the deck, or below deck, as all the appliances in the wheel house for steering, &c., are duplicated below. By means of a hand lever beneath the wheel, steam is admitted to a small auxiliary engine which works the cam that adjusts the paddles. Then by turning the horizontal hand wheel in either direction, the helmsman controls the movement of the cam, as desired. Just above the wheel is a dial with a pointer, which enables him to note the position of the paddles, and so adjust them as ordered. Inside the wheel house there are also devices for communicating with the men working the bow gun, and with those managing the torpedoes.

Her Armament—Engines.—At [Fig. 146] is shown the spar and mode of working it. It consists of a long hollow iron cylinder lying on its supports between decks. Its outboard end rests in a kind of trough, and to this extremity the torpedo is fixed. The spar is controlled by means of tackles and a steam winch. The side spars are 18 feet, and the bow spar 32 feet in length. If the hostile vessel is defended by torpedo guards, by means of a mechanical contrivance the torpedo signals the fact, and is not exploded until the vessel has forced the obstructions. The engines of the Alarm are compound, with four cylinders, the condenser being placed between them. There are four cylindrical tubular boilers with an aggregate heating surface of 4,600 square feet. Her speed is about 16 knots. Her upper deck is only 3 feet above the water. She is fitted with an electric light, and also with machine guns on her broadside.[N]

This is undoubtedly a most formidable vessel, both as a ram and a torpedo ship, and if capable of performing all that is expected of her, will prove a valuable addition to the United States Navy.

THE "ALARM" TORPEDO SHIP.

Captain Ericsson's Torpedo Vessel "Destroyer."—This torpedo vessel was devised and built by Captain John Ericsson. The Destroyer is 130 feet long, 11 feet deep, and 12 feet beam, extreme; both ends of her hull are precisely alike, and terminate with very fine wedges. The rudder is attached to a vertical wrought iron post welded to a prolongation of the keel, just abaft the propeller, as shown at [Fig. 147]. The tillers consist of thin plates of iron riveted on opposite sides of the rudder, a few inches from its bottom. These tillers are operated by straight rods connected to the pistons of horizontal hydraulic cylinders of 5 inches diameter, which are attached to the sides of the keel. The steering gear by the above arrangement is placed 10 feet below the water line, while the top of the rudder is 6 feet below the same, and thus perfect security is afforded to this most important feature of a torpedo vessel. The intention of the designer in constructing this vessel is to render her so far impregnable, that in attacking bow on she can defy the opponent's fire, at the same time offering absolute protection to her commander and steersman, and also protecting the base of her funnel. The leading feature of the construction of the hull of the Destroyer is its being provided with an intermediate curved deck, which extends from stem to stern, and which is composed of plate iron strongly ribbed, and perfectly water-tight. This intermediate deck supports a heavy solid armour plate, fixed transversely to the line of keel, and 32 feet from the bow, inclined at an angle of 45°, and supported on its after side by a wood backing 4 feet 6 inches in thickness. Behind this formidable shield the steering wheel is manipulated, a wire rope extending from its barrel to a four-way cock placed near the stern, by means of which water pressure is admitted alternately to the hydraulic cylinders, previously mentioned, the motion of whose pistons actuate the rudder. The lower division of the vessel is ventilated by powerful blowers, and contains the machinery; it also affords a safe retreat for the crew during the attack. The upper division is filled with blocks of cork, excepting a small part near the bow, occupied by the aforesaid armour plate and wood backing.

The deck house is 70 feet long, and composed of plate iron, riveted water-tight to the upper part of the hull. As there are no openings in the sides of this deck house, the vessel may be run with her upper deck under water.

Armament of the "Destroyer."—The Destroyer is to be armed with torpedoes somewhat similar to the projectile torpedo, drawings of which were submitted by Captain Ericsson, the inventor, to Emperor Napoleon III. in 1854. The present weapon is composed of a solid block of light wood, the explosive charge being contained in a metallic vessel inserted at its forward end. Instead of being circular, as was the case with the original torpedo, its transverse section is square, with parallel top and bottom and vertical sides, forming very sharp wedges at both ends, cased with steel plates. The extreme length of the Destroyer torpedo is 23 feet. Ignition is effected by means of a percussion fuze placed in the head of the weapon.

Operating the Torpedo.—The method of operating the torpedo is that of inserting it into a horizontal tube near the bottom of the vessel, provided with valves for keeping out the sea during the process of insertion, as shown at [Fig. 148]. When near the hostile vessel, this valve is opened, and the torpedo expelled by a piston actuated by steam power, the expulsion being effected without recourse to gunpowder or other explosive agent. The area of the actuating piston of the Destroyer is 314 square inches, while the sectional area of the projectile is only 196 square inches; this difference in size of the two areas is a special and important feature of the invention, as will be understood from the following: the tension of the acting medium in the Destroyer exceeds 200 lbs. per square inch, therefore the torpedo will be pushed out by a force of (314 × 200) / 196 = 320 lbs. per square inch, and as the distance passed by the piston while impelling the torpedo is 30 feet, an energy of nearly 2,000,000 foot-pounds will be imparted to the projectile.

When making an attack, it is intended that the vessel should at the instant of firing her torpedo reverse her engines, this retrograde motion being greatly assisted by the recoil, which must attend the discharge of a body weighing some 1,400 lbs. impelled by the aforesaid enormous force, and moving through a distance of 30 feet before reaching the water.[O]

Certainly this new system of submarine attack seems feasible, but it has yet to prove, in common with all other new inventions, whether its theoretical capabilities are also practical ones. At [Fig. 149] is shown a general view of this novel torpedo vessel under weigh.

[THE "DESTROYER" TORPEDO SHIP.]

Torpedo Boats.—In offensive torpedo warfare, whether using the spar, locomotive, or towing torpedo, especially in the case of the former class of submarine weapons, to ensure a successful attack it is absolutely essential to operate those weapons from steam boats, which are capable of fulfilling as near as possible the conditions herein enumerated:—

1.—They should be capable of steaming at least 18 knots per hour.

2.—Their engines should be noiseless, and easily managed.

3.—They should be extremely handy.

4.—No smoke should enable their approach to be detected, or glare from their fires.

5.—That it should be possible to raise steam in them in a few minutes.

6.—They should be built in water-tight compartments, and covered fore and aft to prevent being swamped.

7.—The crews should be protected as far as practicable from rifle fire.

In addition to the foregoing, for the purpose of rendering these craft capable of defending themselves against the attack of guard boats, and also of being employed as such, and on river expeditions, &c., they should be built sufficiently strong to enable them to carry a small gun either in the bows or stern; this would apply more especially to those torpedo boats which are part of a ship's stores.

During the last four years a very large number of torpedo boats have been built, which more or less fulfil the aforesaid conditions, nearly the whole of which have been constructed by the two English firms, viz. Messrs. Thornycroft and Co. and Messrs. Yarrow and Co., and to the latter firm is due the honour of constructing the fastest vessel as yet in the world.

Up to the present time, a specially built torpedo boat has on only one occasion been used on active service, viz. at the attack on a Turkish monitor on the 20th of June, 1877, which is detailed at length in the following chapter. This boat was one of Messrs. Thornycroft and Co.'s launches, and from all accounts she behaved wonderfully well under the most untoward circumstances.

Thornycroft Torpedo Launches.—Messrs. Thornycroft and Co., of Chiswick, London, have during the last six years built a large number of torpedo launches for the English government and for several of the principal European governments.

Norwegian Launch.—The first torpedo boat ever built by this firm was the one shown at [Fig. 150], for the Norwegian government. This boat was 57 feet in length by 7 feet 6 inches beam, drew 3 feet of water, and the stipulated speed was 16 English statute miles, or nearly 14 knots per hour; which speed was not to be ascertained by a mere measured mile trial, but was to be 16 miles through the water in a run of one hour's duration.

The hull of the vessel was constructed entirely of steel plates and angle bars, and, as may be seen from the diagram, was divided into six water-tight compartments, A, B, C, D, E, F.

The compartments marked A and F in the stem and stern were for stores; those marked B and E were fitted with seats for the crew, and were provided with movable steel covers, so that on going into action, or during rough weather, they might be completely covered.

The compartments C and D are for the steersman and the machinery respectively, and were covered completely by steel plating 3/16 of an inch in thickness—a thickness sufficient to withstand Snider or Martini-Henry bullets, fired from a distance of twenty paces.

The compartment D was furnished with a hood, having slits 1/4 of an inch wide, all round, through which the steersman could see with sufficient distinctness to direct his course easily. Motion was communicated from the wheel to the tiller by means of steel wire ropes, which it was originally intended should be encased in wrought iron tubes.

The possibility however of these tubes being bent by a shot, and so jamming the wire ropes, led to this arrangement being abandoned, and the ropes were simply run through eyes at intervals along the side.

The armament consisted of a cylindro-conical shaped torpedo towed from the top of the funnel, round which a ring was fitted with two pulleys for the towing rope, the strain being taken off by means of two stays attached forward.

The length of this torpedo was 13 feet and the diameter 9 inches, and with a speed of 11 knots it has diverged to about 40 degrees from the direction of the boat's motion when running in smooth water.

The torpedo is worked by means of a small winch and brake fixed on the after part of the engine room skylight; davits are provided for dropping the torpedo overboard.

The engines were compound, of the usual inverted double cylinder direct acting type, capable of developing about 90 indicated horse power, and were fitted with a surface condenser, so that the vessel could run in salt water, without danger of injuring her boiler.

A small tank contained a supply of fresh water, to make good deficiencies arising through leakage, and from steam escaping at the safety valves, &c.

The circulating, air, and feed pumps were driven by a separate engine.

The boiler was of the locomotive type, the shell being made of Bessemer steel; the fire box and its stays of copper, and the tubes of solid drawn brass.

On the official trial, which took place on the Thames on the 17th of October, 1873, the number of revolutions done in the hour was found to be 27,177, and the number required to do a mile in still water was 1578. The distance run in the hour was then, 27,177/1578 = 17·22, or very nearly 17-1/4 miles.

The steam pressure during the trial averaged 85 lbs. per square inch, and the vacuum 25-1/2 inches.

Swedish and Danish Boats.—Boats of the same size and similar in all particulars to the foregoing one—excepting the engines, which are improved by driving the air pump, feed pump, and circulating pumps off the main engines, and abolishing the auxiliary engine, which performed these duties in the case of the Norwegian boat—were made for the Swedish and Danish governments. The result was an increase of speed to 17·27 miles in the case of the Swedish boat, and to 18·06 miles, or 15-5/8 knots, in the case of the Danish boat.

There is no information regarding the armament of the Swedish boat, but the Danish boat was armed with two spindle-shaped torpedoes 12 feet long and 11-1/2 inches diameter, somewhat like the Whitehead torpedo. They were placed on deck longitudinally near the funnel, so as to facilitate launching, and were arranged to be towed from an upright pole 8 feet high, placed about 6 feet from the stem.

A small winch was fixed on either side aft, to pay out the towing line, and to bring back the torpedo. By these arrangements the torpedo could be projected at a large angle from the direction of the boat's motion, and at considerable velocity. The speed of the boat when towing one of these torpedoes is about 10 knots.

Austrian and French Boats.—The next size of torpedo vessel is that supplied to the Austrian and French governments, which is shown at [Fig. 151]. The dimensions are:—length, 67 feet; beam, 8 feet 6 inches; draught of water, 4 feet 3 inches. The guaranteed speed in the case of the Austrian boat was 15 knots in a run of one hour's duration, and in the case of the French boats 18 knots, in a run of two hours' duration. These boats were built of somewhat thicker plating than the 57 feet type, and the armour was extended.

They were divided into six water-tight compartments, and they differed from the Scandinavian boats in having the spaces forward and aft of the machinery permanently decked, instead of being covered with movable steel covers only.

The machinery was somewhat similar to that in the Scandinavian boats, excepting that the engines were capable of developing 200 indicated horse power, and that the air was supplied to the furnace by being forced into an air-tight stoke hole, instead of being forced directly under the fire grate.

The armament of these vessels consisted of two torpedoes attached to the end of wooden poles, 4-1/2 inches diameter and about 43 feet long, connected to the battery by insulated wires, and arranged to be fired either by coming in contact with the enemy's vessel or at any distance from it, at the will of the operator.

The torpedoes themselves were simply copper cases, of sufficient size, in the case of the Austrian boat, to contain 11,000 cubic centimetres of explosive, and in the case of the French boats, to contain 25 kilogrammes of dynamite.

The mode of arranging the wires is similar to that explained at [page 155]. The method of manipulating the torpedo poles consists of two tubes riveted together at right angles, so as to form something like the letter T. The torpedo pole is put through the horizontal tube, which is free to move round the centre of the vertical tube, and the vertical tube is free to move through a quarter circle at right angles to the centre line of the vessel.

In attacking in front, the vertical tube is laid over till it is parallel to the water surface, and the horizontal tube is allowed to incline sufficiently far to allow of the end of the pole, when run out, to be depressed from 8 to 10 feet below the water-line. It is held in this position by a pair of blocks attached to the top of a short mast.

In attacking on the broadside, the vertical tube is laid over till it assumes a position such as to allow of the pole, when swung round, to touch an enemy's vessel at about 8 or 10 feet below the water line.

The speed trials of the Austrian boat took place on the 11th of September, 1875, when she did 24,700 revolutions on her hour's run on the Thames, and the number of revolutions required to do a knot in still water was found to be 1357. This gives the distance run in the hour as 18·202 knots, or 3·202 knots over the contract speed. The steam pressure averaged 105 lbs. per square inch, and the vacuum 25-1/2 inches during the run.

In the case of the French boats, the total number of revolutions done in the two hours' run in the roadstead off Cherbourg was 49,818, and the number required to do a knot in still water was found to be 1382, so that the distance run in the two hours was 36·05 knots, or just over the contract speed. During the two hours, the average steam pressure was 108 lbs. per square inch, and the vacuum 25 inches.

The Austrian boat was sent to her destination on board a steamer, but the French boats, under the command of an experienced captain, steamed by themselves from Chiswick to Cherbourg, not crossing at the nearest points and running along the shore, but going boldly from Dover direct to Cherbourg.

Shortly after the arrival of the French boats in Cherbourg, they were altered so as to attack in front only, as the French authorities found that these small vessels were better adapted for resisting the effects of an explosion at the bow than at any other part.

The arrangement adopted is shown at [Fig. 152], and consisted of a steel pole about 40 feet in length, having one end about 6 inches diameter, and solid, and the other about 1-1/2 inches diameter, and hollow; this pole was mounted at its solid end on small pulleys, which ran upon two ropes stretched fore and aft of the vessel; the other end, to which the torpedo was attached, was led over a pulley fixed on the bow. Ropes passing over pulleys to a windlass in the after compartment were attached to the inboard end, and by turning the windlass the pole was drawn backwards or forwards as required.

It will be observed that as the pole is drawn forward, the inboard end being constrained to move in a line parallel to the deck, the outer end is depressed in the water, and is so adjusted that when the pole is run out to its full extremity, the torpedo is depressed to about 8-1/2 feet below the water level.

Dutch and Italian Boats.—The third size of boat built by this firm for the Dutch and Italian governments are 76 feet long and 10 feet beam, and are guaranteed to do a speed of 18 knots. These boats are similar in design to the Austrian and French boats previously described, but differ from them in having engines of 250 indicated horse power, and in having more free board forward, so as to make them better sea boats.

The Dutch type are armed with the outrigger torpedo, as fitted to the French boats, and the Italian type with the Whitehead fish torpedo.

The "Lightning" Type of Boat.—Now comes the Lightning type of vessel, which is shown at [Fig. 153]. This vessel, built for the English government, is 84 feet long over all, 10 feet 10 inches beam, and draws about 5 feet of water. The machinery on board the Lightning is similar in design to that already described, and is capable of indicating 350 horse power. The hull of the Lightning is made of heavier plating than usually employed, and her lines are fuller, as she is intended for use in a tolerably rough sea if necessary; and in order that she may be able to remain at sea for some time, cabin accommodation on a scale larger than in any of the other boats is provided for the officers and crew. The steering gear is arranged so that the vessel may be steered from the deck, or from the conning tower, and the usual telegraph gear is fitted to communicate from the deck, or from the conning tower, to the engine room.

The top of the conning tower is supported on three screws, so arranged that it may be raised or lowered, and the space for sight adjusted according to the range of vision required, or the risk to be run from the enemy's missiles.

The Lightning is armed with fish torpedoes, which are discharged from her deck forward by means of a discharging apparatus.

The torpedoes are charged with air, by means of one of Mr. Brotherhood's air-compressing pumps.

The Lightning on her preliminary runs attained a speed on the measured mile of 19·4 knots per hour, a speed which will be somewhat reduced when she has her torpedoes, &c., on board, but which will then be over 18 knots per hour.

Several torpedo boats have been built and are in process of construction by this firm for the English government.

THORNYCROFT'S TORPEDO BOATS.

French Boats.—The next size of boats is the 87 feet type, as shown at [Fig. 154]. Of this type of torpedo launch several have been built and are now under construction for the French government.

These vessels are 10 feet 6 inches beam; draught of water about 5 feet. They are built of heavier plating than the Lightning, and are guaranteed to maintain a speed of 18 knots. The propellers in these boats are placed in front of the rudder, so as to give increased readiness in steering. In order to prevent oxidation as far as possible, the plates and frames below the water line are galvanised. A spark-catching apparatus is fitted to the base of the funnel, so as to prevent the position of the boat being betrayed to the enemy at night.

The armament of these vessels consist of an outrigger arrangement similar to that described at [page 167]. They are also well adapted for the Whitehead torpedo. They are also provided with a strong buffer in the bows for deadening the shock, in the event of their coming into contact with an enemy's vessel at too high a rate of speed.

"Second Class" Boats and Mode of Manipulating the Fish Torpedoes from them.—Another type of Thornycroft torpedo boats, several of which have been built for continental governments, and which is termed "Second class," is shown at [Fig. 155]. These boats are 60 feet long, 7 feet 6 inches beam, and draw some 3 feet of water; their guaranteed speed being 16 knots per hour. The mode of carrying the Whitehead fish torpedo, and manipulating it from such a boat by means of Mr. J. I. Thornycroft's invention, which has been fully described at [page 140], is shown at [Fig. 155] and [156], where Fig. 155 represents both torpedoes housed, and [Fig. 156] one torpedo in the firing position, the other one being housed.

Four of this type of Thornycroft torpedo boats were attached to H.M.S. Hecla during her recent cruise in the Mediterranean, and have been very favourably reported on as follows:—They do not suffer from the blows of the sea, nor from the strains incident upon hoisting in and out; nor yet when they are suspended ready for lowering, in which latter position they have frequently remained for twenty-four hours; that under careful management they are perfectly safe in a heavy sea, and they possess good manœuvring powers.

The Thornycroft torpedo frames were found to perform well the services for which they are intended. When proceeding at ordinary speed they are nearly noiseless, and cannot be seen on a dark night at a distance of 100 yards.

The Thornycroft Propeller.—All the torpedo boats built by this firm are fitted with the propeller invented by Mr. Thornycroft, and which bears his name. It is a modification of what is known as the Dundonald propeller, the principal difference being that in the Dundonald propeller the blades are inclined backward in straight lines, while in the Thornycroft propeller they are curved.

Experiment at Cherbourg.—The following account of an experiment which took place at Cherbourg in March 1877, whereby to test the efficiency of a Thornycroft torpedo boat in exploding a spar torpedo under the bottom of a vessel proceeding ahead at the time, is taken from the Times, under date the 13th of March, 1877.

[THORNYCROFT'S TORPEDO BOATS.]

"Admiral Jaurez, who commands the squadron, ordered a disabled ship, the Bayonnaise, during a rather rough sea, to be towed out by a steamer belonging to the navy. A second lieutenant, M. Lemoinne, was sent for, and informed that he had been selected to make the experiment of launching the Thornycroft against the Bayonnaise while both were in full sail. He accepted the mission without hesitation, picked out two engine men and a pilot, and went down with them into the interior of the Thornycroft, of which only a small part was above water; this visible portion being painted of a greyish colour, so as to be easily confused with the sea. The torpedo was placed so as to project from the bow of the vessel, at the extremity of which were two lateen sailyards about three metres in length. The towing steamer then took up its position in front of the squadron, and the Thornycroft also assumed the position assigned for it; an interval of three or four marine miles separating the torpedo boat and the Bayonnaise. On a signal being given, both were set in motion, the steamer advancing in a straight line, and the Thornycroft obliquely, so as to take the Bayonnaise in flank. The steam tug went at 14 knots an hour, going at full speed in order to escape the Thornycroft. The latter went at 19 knots an hour, a rate not attained by any vessel in the squadron. The chase lasted about an hour, the squadron keeping in the rear, so as to witness the operations. At the end of that time the distance between the Thornycroft and the Bayonnaise had sensibly diminished, and at a given moment the former, in order to come up with the latter at the requisite distance, had to slacken speed to 8 knots an hour. The whole squadron watched this last phase of the struggle with breathless interest, and people asked themselves whether the shock of the torpedo would not infallibly destroy the little vessel which bore it. It was feared that the lives of the second lieutenant, Lemoinne, and his three companions were absolutely sacrificed. However, the two vessels got visibly nearer. All at once the Thornycroft put on a last spurt, and struck the Bayonnaise with its whole force on the starboard bow. The sea was terribly agitated, a deafening report was heard, and the Bayonnaise, with a rent as big as a house, sank with wonderful rapidity. As for the Thornycroft, rebounding by the shock about fifteen metres off, even before the explosion occurred, it went round and round for a few moments, and quietly resumed the direction of the squadron. No trace remained of the Bayonnaise; it was literally swallowed up by the sea."

The experiment was a most complete success, the torpedo boat not being in the least degree injured.

The Power of Flotation of a Thornycroft Boat after being pierced by a Rifle Shot.—On the 5th of July, 1877, Messrs. Thornycroft and Co. made an experiment with one of their torpedo boats to ascertain under what conditions flotation is still retained after the boat has been pierced by a rifle shot.

The torpedo boat experimented on was similar to the one which has been described at [page 169]. A Martini-Henry was fired through her side, about a foot under water in the stoke hole. Whilst at anchor the water entered in sufficient quantity to fill an ordinary size bucket in twenty-five seconds, but when she was driven ahead less water entered, and on the speed of 10 knots being reached, little or no water entered. The hole was a little more than three quarters of an inch in diameter.

The engagement on the Danube between the torpedo boat Schootka and some Turkish vessels, in which the former vessel was pierced by bullets, but yet did not sink, led to the above experiment being carried out.

Efficiency of Thornycroft's Engines.—As a practical proof of the efficiency of the engines supplied by Messrs. Thornycroft and Co. to their torpedo boats, a similar engine has been used for over two years to work the various machines in connection with their works at Chiswick.

Torpedo Boats built by Messrs. Yarrow and Co.—Messrs. Yarrow and Co., of the Isle of Dogs, London, are also very well-known torpedo boat builders, and have during the last four years constructed a considerable number of such vessels for the English and different continental governments, and, as has been before stated, they are the constructors of the fastest vessel in the world.

Dutch Torpedo Launch.—In 1875 this firm built a torpedo launch for the Dutch government, specially designed for ocean purposes. It was 66 feet long, 10 feet beam, and 5-1/2 feet deep. She was driven by a pair of inverted direct acting engines. The boiler was of the locomotive type, with a working pressure of 140 lbs. per square inch, and capable of exerting a force of some 200 indicated horses.

Russian Torpedo Boat.—This firm also constructed for the Russian government two torpedo steamers 85 feet in length. The guaranteed speed of these vessels being 20 knots per hour. In 1878 the Russian government ordered one hundred exactly similar boats to be constructed, mostly at St. Petersburg, thus proving the high estimation held by that government of Messrs. Yarrow and Co.'s torpedo boats.

Description of a Yarrow Torpedo Launch.—[Figs. 157], [158], and [159] show an elevation, section, and plan of a torpedo boat, Yarrow type, a large number of which have been built for the Russian and other continental governments.

The length of this boat is 75 feet, its beam 10 feet, and draught of water 3 feet. She is built of steel of the best quality, no other metal possessing the requisite strength and stiffness for scantling, and plates of such lightness. It is divided into eight compartments by seven transverse bulkheads, the forward and after compartments being used for stores, the two central ones enclosing the machinery, while the steersman and operator are placed in the compartment immediately abaft the engines.

The steersman's head projects above the deck, and is protected by a rifle proof steel truncated cone, the top part of which is movable like the visor of a helmet. The hull is decked over from end to end with a curved shield, the midship plating of which is capable of resisting rifle shots, even at close quarters; its curved form being well adapted for giving the maximum strength to the structure, and quickly frees itself from any large body of water.

[YARROW'S TORPEDO BOATS.]

The propelling machinery consists of a pair of inverted compound condensing engines. The revolutions per minute at full speed are about 470, and the indicated horse power about 280. The propeller is of steel. The funnel is fixed at one side of the centre line, to be out of the way of the bow torpedo pole and gear.

This type of torpedo boat attains a speed of from 17-1/2 to 18-1/2 knots per hour.

The armament of some of these boats consists of three spar torpedoes, a bow, and two quarter ones. The bow pole, which is strong and heavy, is hauled out and in by means of a small auxiliary engine.

Boats similar to these, but of larger dimensions, viz. 84 feet long and 11 feet beam, have also been constructed by this firm. Speed from 19 to 20 knots per hour.

English Torpedo Boats.—The following account of two torpedo boats which had been originally built by this firm for the Russian government, but, owing to the proclamation issued by the English government at this time prohibiting torpedo boats leaving England, were seized by the Customs authorities when on the point of completion, and were ultimately purchased by the English government, is an extract from the Times under date the 4th of July, 1878.

"These vessels are each 85 feet long with 11 feet beam, and draw, when fully equipped for service, an average of 3 feet of water. They are strongly constructed of steel, and are fitted with compound surface condensing engines capable of indicating 420 horse power. The high pressure steam cylinder of these engines is 12-1/2 inches in diameter, and the low pressure 21-1/2 inches, both having a 12 inch stroke. These boats are at present known by their builders' numbers, one being No. 419 and the other No. 420. The former is propelled by a three-bladed screw, 5 feet 6 inches diameter and 5 feet pitch; and the latter by a two-bladed screw of similar proportions. Messrs. Yarrow adopt supplementary engines for driving the air pump, circulating pump, and feed pumps; they consider this plan preferable to that of working these pumps direct off the main engine, as is sometimes done. One advantage in having separate pumping engines is that, whether the vessel is in motion or stationary, a powerful means is available for pumping her out, should the necessity arise. It is estimated by her builders that if the air pump and circulating pump were both utilised for this purpose, the water could be pumped out as fast as it could enter either of these vessels through one hundred holes made in the skin by Martini-Henry rifle bullets. If this is the case, these craft may be deemed safe from sinking so long as their machinery is working efficiently. The boiler is of the locomotive type, placed in the forward part of each vessel, and has a closed stoke hole. In connection with the boiler a very important improvement has been introduced by Messrs. Yarrow. This consists in a means of rendering the closed stoke hole safe for the men in the event of the collapse of a boiler tube—a contingency which cannot be absolutely guarded against. Its efficiency was proved beyond all question upon a previous trial of one of these boats. This was No. 419, which was tried on the 24th of May last under the supervision of the Admiralty officials. Upon that occasion an accidental rupture of one of the boiler tubes occurred nearly at the close of the runs over the measured mile, which so far had been very successful. When the boiler tube gave way the steam rushed out of the foremost hatchway from the compartment in which the smoke box end of the boiler is situated, and soon after from the two funnels. The men in the stoke hole, however, being shut off from the boiler, were uninjured, and remained at their post several minutes after the first outburst of steam. The accident, although an untoward event, was considered by the Admiralty officials as affording a highly satisfactory proof of the efficiency of Mr. Yarrow's invention.

"The engines are placed amidships, and each vessel has spacious cabin accommodation aft, as it is intended that they may be used either as despatch or torpedo boats. For the latter purpose the cabin framings above deck are removed and replaced by steel plating. They are steered from the cabin, there being a look-out for the steersman just above deck level. The deck is clear of all obstructions, the two funnels being placed one on either side. They are fitted with balanced rudders and steer well, answering their helms very quickly."

The trials of these two torpedo boats are taken from the Engineer under date the 19th of July, 1878. At that time these boats completely eclipsed in speed everything that had hitherto been done. At [Fig. 160] is shown in elevation this type of torpedo launch.

"The trials were personally conducted by Mr. Yarrow, under the superintendence of the authorities from Whitehall, and consisted in a two hours' run without stopping, during which time the boats were tested at the measured mile at Long Reach. Each boat was run six times over the mile, three runs with the tide and three runs against it. The boats and machinery are similar in every respect, excepting that No. 419 is fitted with a three-bladed propeller, and No. 420 a two-bladed one, their diameters and pitch being the same in both cases. The weights on board were accurately weighed, and amounted to 6 tons in each boat, including coals, water, crew, and ballast.

"Trial of No. 419.

Min. Sec. Knots per hour.
1st run down occupied 23623·076
1st run up"32018·000
2nd run down"23523·226
2nd run up"31618·367
3rd run down"23223·684
3rd run up"31418·557

Mean of the six runs, 20·818 knots per hour.
Mean steam pressure, 115 lbs. per square inch.
Vacuum, 23½ inches.
Mean revolutions of main engines per minute, 456.

"Trial of No. 420.

Min. Sec. Knots per hour.
1st run down occupied 2 33½23·452
1st run up"325½17·518
2nd run down"232½23·606
2nd run up"32117·910
3rd run down"23223·684
3rd run up"32417·647

Mean of the six runs, 20·636 knots per hour.
Mean steam pressure, 115 lbs. per square inch.
Vacuum, 24 inches.
Mean revolutions per minute, 466.

"The highest speeds were obtained by No. 419, during the third runs up and down, the mean of which give 21·12 knots, which is equal to 24-1/3 statute miles per hour, during which time the engines were making 470 revolutions per minute. At the close of the runs, the bearings were found to be in first-class condition, and there was not the least sign of anything getting warm during any part of the trials."

Spanish Torpedo Boat.—The following description of a torpedo boat built by this firm for the Spanish government, enumerating all the improvements that have of late been effected in the construction of such vessels by members of this firm, is taken from the Engineering under date the 21st of February, 1879.

"The alterations have a twofold character, and have reference to the arrangements for discharging the products of combustion from the furnaces and to those for steering the vessel. In brief, the boat is funnelless and is fitted with two rudders, one at each end. The main object in dispensing with the funnel is to enable the torpedo boat to approach as closely as possible to an enemy without being seen, a secondary, although still an important, consideration, being the absence of any obstruction to the steersman's view, such as a funnel on deck. The outlets for the smoke in the present instance are two ports, one on either side of the vessel, and placed about 15 feet in from the bow. Each of these smoke ports is fitted with a damper, and the smoke can be turned through either or both of the passages as desired. The control of these dampers is given to the steersman, who, on approaching an enemy, can direct the products of combustion through the port on the unexposed side of the vessel. The emission of smoke by day and of the glare and sparks by night are thus to a very large extent hidden from view, thus enabling the torpedo boat to approach very closely to the point of attack without being observed. The outlets are fitted with valves which are kept open by the blast, but which close on being struck by a passing wave. Should the vessel have to be out when a heavy sea is running the ports are closed, and a spare funnel is rigged up on deck, on one side. Although the smoke ports are placed forward in this boat, it is intended to place them aft in the next that Messrs. Yarrow build, as that arrangement will obviate the inconvenience at present experienced by those on deck from the heated gases of the furnace being carried along it at times by the wind, when on a certain course.

[YARROW'S TORPEDO BOATS.]

"The steering powers of the boat have next had attention from Messrs. Yarrow, and they have sought to remedy the defective steering common to these large quick-speed torpedo craft. To do this they have fitted the vessel under notice with two balanced rudders, one of which is placed forward about 10 feet from the bow, and the other in its usual position at the stern with the screw abaft it. Both rudders are connected with the same steering gear, and are operated simultaneously by one steersman. The forward rudder can be raised out of the water into a casing inside the boat if desired by means of a screw cut on the upper part of its spindle. By the same means, by unscrewing the collar on the spindle, the rudder can be released and dropped into the water should the necessity arise for so doing, by reason of its becoming fouled or damaged. In trials which have been made with this double-steering system, it has been found that when steaming at high speeds the forward rudder has a much greater control over the motion of the boat than the stern one. The reason assigned for this is that at high speeds the forward part of the boat is lifted out of the water, and consequently offers a diminished side resistance to any turning motion brought to bear upon it.

"The boat in which these improvements have been introduced is 86 feet long by 11 feet beam and 5 feet 6 inches deep. She is fitted with compound engines having 22 inch and 12-1/2 inch cylinders, with a 12 inch stroke, and making 520 revolutions per minute when running at full speed. She is propelled by a three-bladed screw 5 feet 6 inches in diameter and 5 feet pitch. Put through some evolutions with the view of testing her steering powers, the double rudder arrangement was found to answer exceedingly well, and she turned a circle of a diameter equal to about three times her own length in 1 minute 15 seconds. She turned equally well either going ahead or astern, and in fact her steering capabilities were satisfactorily demonstrated. The new arrangement for carrying off the smoke also answered very well, with the exception that the heated gases occasionally swept the deck, which objectionable result will be avoided in future boats."

These boats are to be armed with spar torpedoes, and with the Whitehead fish torpedo, the cradles and fittings for which are shown at [Fig. 161].

The Fastest Vessel in the World.—Another type of torpedo boat, of which one of the same dimensions has been built by this firm for the English government, is shown at [Fig. 162]. This vessel is as yet the fastest vessel in the world. The trials with this boat were made in March of this year, and were as follows:—

Runs.Time, Knots
per hour.		 Knots
per hour.
Min. sec.
First2 37 = 22·93 Mean of first pair = 21·35
Second3 2 = 19·78
Third2 33 = 23·53 Mean of second pair = 22·05
Fourth 2 55 = 20·57
Fifth2 30 = 24·00 Mean of third pair = 22·23
Sixth2 56 = 20·45

giving as a mean 21·93 knots per hour, or 25-1/4 statute miles. The boat was fully equipped for active service, i.e. with a load of 6-3/4 tons on board. It was found during the trial that at speeds of 17 and 19 knots the vibration of the boat was considerable, but when running over 20 knots it was hardly perceptible; the excessive vibration taking place when the revolutions of the engines became a multiple of the natural vibration of the boat.

Torpedo boats are at the present time being built by this firm for the English, French, Spanish, Austrian, and Italian governments.

Russian Torpedo Boats, built by Mr. S. Schibau, Prussia.—Mr. S. Schibau, of Elbing, Eastern Prussia, in 1878 constructed ten torpedo boats for the Russian government, similar to the one shown at Fig 163.

These boats are each 66 feet long, and 11 feet 3 inches beam. They are built of steel plates about an eighth of an inch thick. Their engines consist of three cylinder compounds, with surface condensers; and they run at 380 revolutions per minute, at full speed, driving a screw 4 feet in diameter. They have been variously armed, some with the spar, some with the Whitehead fish, and some with the Harvey towing torpedo. Their speed is about 18 knots per hour.

Messrs. Herreshoff's Torpedo.—Messrs. Herreshoff, of Rhode Island, U.S.A., have also constructed several torpedo boats. One of these, built for the English government, is shown in section at [Fig. 164]. This boat is 59 feet 6 inches long, 7 feet 6 inches beam, and 5 feet 6 inches deep; she draws about 1 foot 3 inches of water.

RUSSIAN TORPEDO BOAT, HERRESHOFF'S TORPEDO BOAT.

"The vessel is constructed with five water-tight bulkheads, and her hull is of composite construction below the water line, having a steel framing covered with wood planking. The upper part of the hull is wholly of steel, the plates being 1/16 inch thick, the top sides sloping inwards and the upper work forming a protective superstructure for the crew and machinery. She is propelled by a screw which is placed beneath the vessel in a central position, and which is driven by a direct acting condensing engine placed in the forward part of the boat. The diameters of the steam cylinders are 10-1/2 inches and 6 inches respectively, with 10 inch stroke, and they are of 100 horse power estimated. There is an independent feed pump and air pump. The stoke hold is enclosed and is supplied with air by a Sturtevant blower, which is driven by an independent engine of 2-1/2 horse power. The propeller is a two-bladed screw 38 inches in diameter and 5 feet pitch, the screw shaft being 23 feet in length. The vessel is steered by means of a balanced rudder placed a short distance from the stern and under the ship, the helmsman being located in a stern cabin with a protected look-out raised just above the deck. The hull and machinery together weigh 6 tons, but with the working crew of four men and fuel, stores, and two torpedoes on board, boat weighs about 7-1/2 tons.

"Steam is supplied by a Herreshoff coil boiler, which constitutes another novelty in this boat. This boiler consists of a circular combustion chamber, which in the present instance is 4 feet in diameter internally, and within which is a coil of about 300 feet of 2 inch pipe coiled to nearly the diameter of the chamber. This coil is continued at the top so as to form a kind of dome under the cover of the combustion chamber. By the side of the boiler is a separator, into which the steam passes before it goes to the engine. The water from the feed pump is admitted at the top of the coil, and during its course to the bottom the greater portion of it becomes converted into steam. Having passed through the entire length of the coil, the steam and water are discharged together into the separator in such a manner that the water is entirely separated from the steam, and can be blown off as required. The steam is taken from the top of the separator, and returns through a short coil placed inside the combustion chamber, where it becomes superheated, and is led thence to the engines. It is claimed for this boiler that it cannot explode destructively, inasmuch as there is but a very small quantity of water in it at any time, and that it is distributed along the entire length of the coil. A rupture at any point would only be attended by a moderate blowing off of steam. The rapid circulation of the water is found to prevent the deposit of salts, the surplus water not converted into steam carrying with it all impurities. A good working pressure can be obtained within a few minutes of lighting the fire, and the boiler can be blown off in a few seconds. The large combustion chamber enables the full economy of the fuel to be realised."[P]

This vessel is guaranteed for a speed of 16 knots per hour. She can be propelled ahead or astern with equal speed, and can be brought to a dead stop when going full speed within a distance equal to her own length. Her turning powers are equally good. Her armament will probably be the fish torpedo.

Ordinary Torpedo Boat.—The most efficient and simple method of fitting and working a spar torpedo from an ordinary steam launch or pinnace is shown at [Fig. 165]. This method will be readily understood from the figure; the dotted lines show the position of the spar and upright, when rigged in. The speed of this type of torpedo boat ranges from 6 to 9 knots. Occasions would no doubt occur in time of war when a torpedo attack by such boats would be a feasible matter, and therefore everything should be done to render these boats fit for that special service.

Defects.—The most important defects of such craft are:—

1.—The noise created by their engines, thus rendering an undetected approach to a hostile vessel impracticable.

2.—Their liability to be swamped by the explosion of the torpedo.

Of course there are many minor defects, but above are the principal ones, both of which might, to a considerable extent, be modified.

Torpedo Boat Attacks.—It is impossible to attempt more than a very general idea of how to conduct a torpedo boat attack, as so much depends upon the circumstances, ever changing, under which each particular attack would have to operate.

The spar and the fish torpedo are the submarine weapons that can best be manipulated from boats, the towing torpedo requiring a more roomy craft than the torpedo boat generally is to operate it from with any chance of success.

Methods of Protecting Ships from Boat Torpedo Attacks.—The principal methods that exist at the present time of protecting a ship from a boat torpedo attack are as follows:—

1.—Booms by themselves, or supporting nets hung vertically, surrounding the ship at a distance of 10 or 15 feet from the side of the vessel.

2.—A crinoline of wire, or chain, fixed by stays to the vessel's side, but capable of being lifted out of the water if required.

3.—The above methods supplemented by guard boats, and a cordon of boats.

4.—A cordon of boats, that is, boats connected at certain distances by means of hawsers, or chain cables, and at a distance of some 200 or 300 yards from the vessel, supplemented by guard boats, but without other protection.

5.—Electric lights and torpedo guns. These latter are small guns capable of penetrating the side of a torpedo boat and of being depressed at a very small angle.

As it is against these defences that torpedo boats would have to contend, therefore they have been described previous to explaining the mode of conducting a torpedo boat attack.

The first two methods of defence are of course quite impracticable when the attacked vessel is one of a blockading squadron, and it is against such vessels that a torpedo boat attack will generally be used and oftenest be successful.

In the case of a vessel forced to anchor in a harbour which is accessible to the torpedo boats of the enemy, by the application of either of the first two methods, supplemented by guard boats and electric lights, she would undoubtedly be almost impregnable against a torpedo boat attack, even were the boats armed with the fish torpedo, though she would of course not be in that state of readiness which is essential to a man-of-war's efficiency. As a general rule, no man-of-war should anchor unless absolutely necessary in the vicinity of an enemy's ports, and then should retain the power of moving in any direction in the quickest space of time possible, using the electric light and guard boats as a means of protection.

An attack by boats armed with the spar torpedo must always partake of the nature of a forlorn hope, this especially applying to the boats themselves, the crews of which, provided they are supplied with good life belts, would seem to run a far greater risk of a wetting and a prison than of being shot.

Not less than four torpedo boats should compose the attacking force. The crews of the boats, consisting of only those actually required, should fully understand "that the hostile vessel is to be torpedoed," i.e. they are not to give up the attack on the vessel opening fire, nor in the case of one or more of the torpedo boats being sunk, but to remember that one boat is sufficient to effectually carry out the object of the attack, viz. the sinking of the ship.

In making the attack, one boat should be directed on each bow, and one on each quarter, the final rush being as combined as possible. There must not be the slightest hesitation, and each boat must make direct for her point of attack.

The cause of the Russians failing so often in their torpedo boat attacks during the war of '77 may be traced to the absence of anything like a system, and to their giving up the attack directly they supposed themselves discovered.

When using the towing torpedo, two boats only could be used, and they should make the attack, either coming down from ahead, one on each side of the vessel, or coming up from the stern, one on each side of the vessel, or by the boats crossing the bow and stern of the vessel in different directions.

In the case of the fish torpedo the attack must be conducted in a different manner, the object in this case being to get within a certain distance only of the vessel undetected, and from thence send the missile on its deadly course. The distance should not be more than 500 yards; the closer up to 200 yards the better. In connection with such an attack, the torpedo boats might be supported by guard boats, whose particular duty it would be to engage the enemy's guard boats and so leave the torpedo boats free to do their particular work.

It has been suggested to use the electric light from the bows of torpedo boats, but this would do away with one of the chief characteristics of such boats, viz. their invisible and unknown approach, on which the whole success of the attack in a great measure depends.

Fosberry's Patent Torpedo Boat Protective.—To enable torpedo vessels and boats to remain afloat after being struck by shot from mitrailleuses, rifles, and other arms usually employed against such craft, and at the same time to retain their structural lightness, Colonel G. V. Fosberry, of the English army, has designed the following method, which is based upon the discovery that when india-rubber or the like is placed and secured on a metal plate, and is penetrated or punctured by a rifle bullet or similar projectile, which also passes through the metal plate, the hole or orifice so formed in the india-rubber will, after the projectile has passed through it and the metal plate, immediately be closed by the elasticity of the surrounding portions, so that no water can follow the projectile through the said hole or orifice. India-rubber or other elastic material, or a combination of such materials, in the form of sheets, belts, or coats, is placed upon or around those portions of the hull of the boat which are to be protected. Vulcanised or mineralised india-rubber is the material usually employed by Colonel Fosberry. Between the metal plates and the india-rubber covering an intermediate substance, generally kamptulicon, is interposed, which is cemented or riveted to the said metal plates, and to which the india-rubber is attached. This intermediate substance, which is the feature of the invention, must be of such a nature that it may be caused to adhere closely and tightly to all parts of the metal, and also to the india-rubber covering, while the same are unperforated, but when the said india-rubber covering and the metal plate under the same are perforated by a bullet, the portion of the said intermediate substance adjacent to the perforation must be detached from the elastic covering and metal plate, and leave the former free to act like a valve, and close up over the hole so that no water may enter; and this intermediate substance, as applied by the inventor in the immediate vicinity of the perforation, will by the effect of the shot be so broken up and detached from the india-rubber covering as to allow the same to recover its original position independently of the new shape or position of the injured and deformed metal plate.

Should the india-rubber be placed upon the metal plates and be so attached to the said plates as to adhere and conform to them in or after their deformation, a hole made in the india-rubber would remain open; on the other hand, should the india-rubber without any intermediate substance be attached to the metal plate in such a manner that it will recover its position after perforation, water would penetrate between the metal and the india-rubber, and by the pressure of this water the india-rubber would be liable to be detached from a large area of the metal plate, and so become ineffective or even dangerous to the boat. Moreover, if the india-rubber is fixed directly upon the metal plates, in the case of a shot passing completely through the boat, that is to say, passing into the boat at one side and out at the other side, a large portion of the india-rubber adjacent to the hole made by the shot in leaving the boat will be torn or destroyed, but this will not be the case in boats constructed according to Colonel Fosberry's patent.

The French government have recently applied this invention to one of their torpedo boats with very successful results, thereby proving that it is not merely a theoretical idea.

Submarine Boats.—Submarine boats, if they could be constructed to fulfil the conditions hereinafter enumerated which are essential to a perfect boat of that nature, would for many reasons be a very important point solved in connection with torpedo operations, and therefore it is most extraordinary that a practicable submarine boat has not yet been designed and built.

Bushnell's Submarine Boat.—The first submarine vessel built for torpedo purposes was designed and constructed by David Bushnell in 1775. This vessel, operated by a Sergeant Esra Lee, was employed in an attempt in 1776 or thereabouts on the Eagle, an English man-of-war, which proved unsuccessful, owing to the sergeant not being thoroughly versed in the management of his curious craft. She was soon afterwards sunk in the Hudson river, but was subsequently recovered by the inventor, though never used again. This vessel was capable of holding one person, and air sufficient to support him thirty minutes without receiving fresh air, and is fully described in 'Barnes's Submarine Warfare.'

Qualifications essential to a Submarine Boat.—A submarine boat should possess the following qualifications:—

1.—It should be of sufficient displacement to carry the machinery necessary for propulsion, and the men and materials for performing the various operations.

2.—It should be of such a form that it may be easily propelled and steered.

3.—It should have sufficient interior space for the crew to work in.

4.—It should be capable of carrying sufficient pure air to support its crew for a specified time, or of having the means of purifying the air within the boat, and exhausting the foul air.

5.—It should be able to rise and sink at will to the required depth, either when stationary or in motion.

6.—It should be so fitted that the crew possess the means of leaving the boat without requiring external assistance.

7.—It should carry a light sufficient to steer by, and to carry on the various operations.

8.—It should possess sufficient strength to prevent any chance of its collapsing at the greatest depth to which it may be required to manipulate it.

The results of former experiments with such boats prove that manual power, which was the original mode of propulsion, is not the motive power best adapted to such a boat; compressed air, gas as used in the Lay torpedo boat, and steam, are all of them far preferable to the original method, but which of these modern ones is the most practicable has yet to be decided.

The most difficult point to be overcome in connection with a submarine boat is that of steering it correctly when beneath the surface of the water.

Confederate Submarine Boat.—The Confederate submarine torpedo boat that sunk the Federal vessel of war Housatonic on the 17th of February, 1864, was built of boiler iron, 35' long, 3' beam (extreme), 5' high in the centre. She carried a crew of nine men. She was propelled by means of a screw propeller worked by eight of the crew, her greatest speed being four knots an hour in smooth water. She carried a sufficient quantity of air to enable the crew to remain submerged for the space of two to three hours. Two fins were fitted on the outside for rising and falling at will, when in motion. There were two manholes provided, fitted with bull's-eyes. This boat was intended to pass under a vessel's bottom, towing a torpedo after her, which was arranged to explode on contact. She was the means of drowning fourteen men before she made her last attempt, when nine others were added to the above list. In her successful attack on the Housatonic, she was armed with the bow spar torpedo, and was sunk, owing to her running into the hole formed by the explosion of her torpedo. About three years after the American civil war was over, this submarine boat was recovered. Divers went down, and found her lying alongside the hull of the Housatonic, with the remains of the nine men in her.

French Submarine Boat "Plongeur."—The boat termed the Plongeur was designed by Admiral Bougois and M. Brune, and was exhibited at the Paris Exhibition of 1867. She was 26' long, 9' deep, and fitted with centre and bilge keels. She carried two small tanks containing compressed air, and four large tanks were placed at the bottom of the boat for the purpose of sinking her, these latter tanks communicating with the water outside and the air tanks. She also was fitted with a compass for steering by, a water gauge to show the depth of submersion, and an air gauge to show the pressure of air in the boat. Rectangular valves were placed at the bottom of the boat for entrance or exit therefrom, for the use of divers, and to affix torpedoes to a ship's bottom. On the top a circular opening for entrance and exit was arranged, also an iron cupola fitted with bull's-eyes. She was also fitted with an apparatus for spraying water through the air in the interior of the boat on its becoming foul, and escape valves for releasing any foul air were placed at the top of the boat. The water tanks were filled by means of pumps, and emptied by means of the compressed air. She was propelled by a three-bladed screw worked by four men. Her rate of progression was about four knots per hour. The anchors consisted of two 15 inch shot, fitted with wire rope cables, working through watertight stuffing boxes.

This vessel has been subjected to some experiments, but with what results is not generally known.

One of the most important uses to which a submarine boat would be put in connection with torpedo operations would be "to discover the exact position and number of an enemy's submarine mines, and if necessary destroy them," the former being an operation in the present day quite impossible to perform, and the latter one rarely to be depended on.