1.—In a boat, which may be either towed, or hauled out to its destination, or may be steered, and controlled by electricity.
2.—By attaching them to buoys so that they are suspended at the proper depths, and then hauled out by means of a warp to an anchor which has been previously placed in position.
Both of the foregoing methods have been successfully manipulated in practice, the first method, where the boat carrying the countermines is towed either by a pulling or steam boat being the most practicable one. A large amount of material would be required for clearing a channel by means of countermines: for example, if the mines to be attacked require 500-lb. gun-cotton charges to be used, 7-1/2 tons of the explosive, besides cables, buoys, &c., would be required to clear a passage about one mile in length and 200 feet in width.
A ship's launch will carry about twelve of these 500-lb. countermines, with all the gear attached thereto.
Experiments to ascertain the effect of countermining have been carried out in England and Europe for the last five years, some of which are given at length in the chapter on "Torpedo Experiments." During the Turco-Russian war, a portion of the Danube was swept in the ordinary and most simple manner by the Turks, and five Russian electro contact buoyant mines were picked up; one other exploded during the process of dragging it to the surface, but no injury occurred to those at work.
Destruction of Passive Obstructions.—To clear away booms, or other passive obstructions, if not possible to cut them away, they may be destroyed by outrigger boats exploding their torpedoes underneath, and in contact, or by attaching charges of gun-cotton at intervals, and then exploding them simultaneously. When a chain is horizontal, and therefore somewhat taut, a charge of 3-1/2 lbs. of gun-cotton (this explosive, being the most effective and convenient for such purposes, should always be used) will be found sufficient to destroy it, no matter what size, and whether the chain is in or out of the water, the charge being of course placed in contact with it. Great uncertainty mustalways attend the supposed clearance of a channel, or passage of submarine mines, as was exemplified during the American civil war, when most of the Northerners' vessels were destroyed while moving over ground which had been previously carefully dragged, and buoyed, and this fact, coupled with the tediousness and danger of performing such a service, proves the enormous value of a system of defence by submarine mines.
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.
[J]'Electricity and Magnetism,' by Professor F. Jenkins.
[J]'Electricity and Magnetism,' by Professor F. Jenkins.
[K]See Appendix.
[K]See Appendix.
[L]As constructed by Mr. J. Mathieson, late R.E., at the Silvertown Telegraph Works, Essex.
[L]As constructed by Mr. J. Mathieson, late R.E., at the Silvertown Telegraph Works, Essex.
THE term "Torpedo" is applicable more particularly to offensive submarine mines than to those employed for the purposes of defence, and therefore bytorpedoeswill 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 ofoffensivetorpedo 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 shouldnotpossess. 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 notresorted 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, bya 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 atFig. 101. It consists of a boxa, containing the charge and fitted with several detonating fuzes. This box is attached to one side of a beamb, 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 beamba heavy weightc, resting in a shoed, is attached by a long iron rode, which reaches to the other extremity of the beam, and is there connected to a bell-crank lever and springf, a pressure on which detaches the weightc; a chaing, 18 feet long, connects the weight loosely with the upper end of the beam, and another chainh, 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 leverfat the upper extremity is pressed down, thus releasing the weightc, which falling, becomes suspended by the two chainsgandh, 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 fromthe 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.
AtFig. 102is shown a plan of this form of drifting torpedo.
It consists of the body of the torpedoa, which contains the charge, at the side of which is placed the loading holeb;cis the tube containing the priming charge;dis the framework surrounding and protecting the wheel or screwe;fis the fuze pillar, in the centre of which is a steel rodg, and on the top a thin steel platehis placed;iis the nipple for the percussion cap;kis a horizontal bar, turning and resting on top of the fuze pillarf;mis the lever for supporting the hammernwhen it is set;lis the screw barrel supporting the wheel or screwe;ois a safety pin;qis the supporting chain, andpthe spring for working the hammern.
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 pillarf, take off the horizontal bark, place a percussion cup on the nipplei, and screw it tightly against the end of the steel rodg. The fuze pillar is then ready for use, and should be screwed into the bodya. Then fill the torpedo with the explosive and close the loading holeb. The hammernis then set by drawing it back and bringing the end of the levermagainst it, at the same time running the screw barrellunder the leverm, so that its end catches the screw of the barrel, as shown in the figure. The safety pinois 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.Plate XXIX
DRIFTING TORPEDOES.
The horizontal leverk, which carries the levermand propellere, rotates on the top of the fuze pillarf, and is prevented from rising by means of a screw. The torpedo being let go, the safety pinois 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 fromunder the end of the leverk, and the latter, dropping the hammern, will be forced by the springpinto contact with the thin steel platehon the top of the fuze pillar, which blow is transmitted by means of the steel rodgto 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.
AtFig. 103is shown a sketch of this torpedo. It consists of a tin case containing about 70 lbs. of powder. A stiff wirea,bpasses through a hole punctured in a strip of tinc, and a stuffing boxd; the endaof the wire is covered with fulminate, and so arranged that the friction caused by its passage through the strip of tincwill ignite it; a number of wires lead frombto pieces of driftwood on the surfacee,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.
AtFig. 104is shown in elevation the small sized Harvey towing torpedo, in which all the latest improvements that have been devised are represented.
ais 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;bis the principal or after lever, hinged on the top of torpedo atc, and rests, when ready for action, in a crutch formed in the top of the exploding boltd;eis the foremost lever, hinged atf, and kept in position on the after leverbby a groove formed in it and a lashing which passes through a slot in the principal lever, as atg;his the side lever, pivoted ati, and exerting a pressure on the firing boltdby means of a lanyard which is passed through the boltkand over the principal leverb;lis the top lever, pivoted atm, and exerting a pressure on the boltdby means of a lanyard which is passed through the boltnand over the principal leverb; this top leverlhas been added to ensure the action of the torpedo, on its striking sideways against a vessel;oandtare handles, to the former of which the lashings of the levershandlare secured;pis the ring used for attaching the buoy rope;r,rare 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;sis 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 leverl, as shown atFig. 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.Plate XXX
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 thelarge 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 atFig. 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 atFig. 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 leverhis brought close into the fair lead, and its lanyard should be set up sufficiently taut to give a slight spring in the principal leverbby the strain thus brought on it. This leverbhas 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 ata,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 needlen, 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 resistancecoil (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 keyk, 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 atFig. 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 therear 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 feetabove 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 sheetbend, 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, willimmediatelydiverge 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 nowbe 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.Plate XXXI
HARVEY'S TOWING TORPEDO.
SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.Plate XXXII
SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.
Recovering the Torpedo.—Should the safety key have been withdrawn, great caution is necessary. Tongs, shown atFig. 109, for going round the upper part of the bolt, to take the place of the safety key, whenonce 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 diagramsTis the torpedo vessel,Sthe ship attacked.
The Track, The Tow Rope The Torpedo
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 atA; 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 byFig. 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 atFig. 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 underthe 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 atA, 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 atFig. 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. SeeFig. 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 atFig. 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 atFig. 115.
Plate XXXIII
SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.Plate XXXIV
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 thebow 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 atFig. 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 whenably handled, yet the skill and judgment required is very great, and can only be acquired byconstantpractice.
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.
AtFig. 117is shown a plan and elevation of this towing torpedo.ais the body of the torpedo, somewhat similar to the Harvey, but narrower at the stern, and bevelled on both sides towards the bow;bis an iron frame placed in the bow, capable of being turned either to the right or left;cis the hole for the introduction of the fuze, anddis the loading hole;eis a rudder placed at the stern of the torpedo;f,fare 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;sandpare two towing ropes, one on each side of the torpedo, which pass from its stern through the point of the frameb, and thence to the vessel, these are also connected to the rudderein such a manner that on either of the ropessandpbeing tautened the ruddereis turned in the opposite direction;wis 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 linesmust be slackened, and the whole towing strain brought on the ropep, causing the framebto be pulled over to a knotkin the ropep, 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 ruddereto be turned to starboard; this is shown atFig. 117by the dotted lines.
To diverge the torpedo on the port quarter, the towing ropepwould be slackened and the whole strain brought on the ropes, 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.