Plate 1.
‘Royal Sovereign’ ‘Camel’
TRIAL OF HARVEY’S SEA TORPEDO.
Kell Bros. Lith. London.
INSTRUCTIONS
FOR THE
MANAGEMENT
OF
HARVEY’S SEA TORPEDO.
LONDON:
E. & F. N. SPON, 48, CHARING CROSS.
PORTSMOUTH: J. GRIFFIN & CO. DEVONPORT: J. R. H. SPRY.
1871.
LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS.
INSTRUCTIONS
FOR THE
MANAGEMENT OF HARVEY’S SEA TORPEDO.
To impart a thorough knowledge of the management of such an arm as the sea torpedo is a matter of easy accomplishment by personal explanation; especially so, when the arm is in the water, and practised with under conditions that would obtain in its application to the disabling of, or to the destruction of vessels against which it may be employed.
But in the absence of such mode of instruction, the following directions are offered, with a hope that they will prove sufficiently explanatory of an arm, which, like other arms, requires skill and aptitude in using it effectively.
By the instructions here given, it must be understood, there are two torpedoes; though both are of the same kind, they differ in construction, by reason of the difference in the position of their respective planes, so that one may diverge to port, and the other to starboard; the direction of the divergence is known by the position of the slings and rudder. There is a like difference in the exploding bolts; the bolts which respectively belong to the port and starboard torpedoes are known by the direction of their safety keys.
(A)
Starboard Torpedo.
(B)
Port Torpedo.
The sea torpedo has the advantage of exploding only when in hugging contact with the vessel attacked; the levers by which it is exploded are so placed in relation to the tow-rope, that either the side or top lever is found invariably to act effectively in forcing down the exploding bolt at the instant of contact; this has been ascertained by the result of many experimental trials.
The shape is an irregular figure, which can be best understood by reference to the drawings ([p. 4]). The dimensions of exterior case are as follows:—
| ft. | in. | ||
|---|---|---|---|
| Large Torpedo | ⎧ Length | 5 | 0 |
| ⎨ Breadth | 0 | 6⅛ | |
| ⎩ Depth | 1 | 8¾ | |
| Small Torpedo | ⎧ Length | 3 | 8 |
| ⎨ Breadth | 0 | 5 | |
| ⎩ Depth | 1 | 6 |
(C)
Section (C).
The exterior case is made of well-seasoned elm 1½ in. thick, iron bound, and screwed together with water-tight packing between the joints, also cemented with pitch. The interior case is made of stout sheet copper; the case has two loading holes corresponding in size to two holes in the deck, or top of the exterior case. These holes are made sufficiently large to load with gun-cotton discs, if preferred. The loading holes are fitted with corks, which are inserted before screwing on the brass cap, to prevent any chance of accident through friction in screwing on the cap; the bushing has the thread of the screw on the outside for the same reason. If thought necessary, the cork can be cemented over before screwing on the cap, which will render the joint doubly secure from leakage. The centre of the copper case has a stout copper tube, which is soldered to the top and bottom surfaces of the copper case, the charge being all round it; into this centre tube is screwed the priming case. It should be understood that both the exterior and inner cases are thoroughly water-tight, so that in the event of the outer case being damaged, still the charge in the interior case is preserved perfectly dry, the cases being altogether independent of each other.
The capacity of the copper case of the large torpedo is such that it will contain 77 lbs. of water; the capacity of the small one, 28 lbs.; from these can be determined the quantity of any explosive agent with which it may be desired to charge either torpedo.
The charges of various powders the torpedoes will contain are as follows:—
| Large Torpedo. lbs. | Small Torpedo. lbs. | |
|---|---|---|
| Glyoxilin | 47 | 16 |
| Schultze’s blasting powder | 60 | 22 |
| Compressed gun-cotton | 60 | 22 |
| Picric powders | 73 | 26 |
| Rifle grained powder | 76 | 27 |
| Horsley’s original | 80 | 28 |
| Horsley’s blasting powder | 85 | 30 |
| Nobel’s dynamite | 100 | 35 |
The above must be considered an approximation, since much will depend upon the labour expended in packing the torpedo.
Some of the powders named have not yet been manufactured on a large scale.
The priming case is made of stout sheet copper, and contains a large bursting charge, which may be either rifle grained powder or a stronger explosive, which is recommended.
(D) Section.
(E)
In the centre of the priming case is a brass tube in which the exploding bolt works, and at the bottom of this tube is a steel-pointed pin, which pierces the capsule on the muzzle of the exploding bolt, when the bolt is forced down. At the side of the brass tube, and near the base of the pin, is a small hole, covered with thin brass foil, which will allow of an escape of water into the priming case, should any have collected at the bottom of the tube. The loading hole of the priming case is at the bottom of the case, and arranged with cork and cap upon the same principle as the loading holes for main charge. A powerful spanner is provided for screwing in the priming case and caps of main loading holes, which are fitted with leather washers to form a water-tight joint. The priming case can be stored separate from the torpedo if preferred, but there is no necessity for so doing unless it is charged with a dangerous compound. When the torpedoes are being stored, a wooden plug is inserted into the brass tube of the priming case; there is a cavity in the plug at the lower end; the cavity is filled with a greasy composition, into which runs the pin of the priming case when the ping is in its place; the pin is thus protected from corrosion, and the tube of the case secured from any foreign matter getting accidentally into it.
The exploding bolt is fitted to work with a pressure of about 50 lbs. on the head of the bolt for the large torpedo, and 20 lbs. for the small.
(F)
On account of the great proportional length of the stuffing box, it is quite impossible for water to enter into the tube, and the pressure can be regulated to the greatest nicety by the quantity of thread wound on. The bolts are easily kept in order by turning them round occasionally in their tubes, stored as they would be in the bolt magazine (see [p. 20], Fig. Y). The best lubrication for them is hog’s lard free from salt, beeswax, neat’s-foot oil, in proportion 3, 1, 1. The bolt has several grooves for the thread stuffing to be wound on, and in the event of its working too easy, a few turns of whity-brown thread on the two lower stuffings will suffice; should it work too stiff, revolve it in the magazine tube until it works with the desired amount of pressure, which, after a little practice, is well known by the hand. In the event of a few drops of water entering the tube, which has never occurred, a provision is made for its escape (see priming case), that it may not impede the descent of the bolt. The cavity in the bolt for containing the exploding composition is, in length and diameter, sufficient to contain a charge that will of itself explode the torpedo (see Fig G), without depending upon the priming case. The bolts are all the same size, and differ only in the direction of the slot for safety key, being port or starboard bolts accordingly.
(G)
(H)
The muzzle of the exploding bolt stands one inch off the pin when in safety position, that is, when the safety key rests on the brasswork of the priming case. This can always be ascertained before entering the bolt (if thought necessary) by a wooden gauge forced down until it touches the point of the pin, which measurement transferred to the bolt will show the distance of the muzzle when forced down to the safety position.
The safety key is secured in the slot of the exploding bolt by eight or nine parts of strong whity-brown thread secured to the key, as shown in Fig. J ([p. 10]), passed round the bolt, and securely knotted in this manner; the parts of the thread come away with the key when drawn, in order that none of the parts may be worked down the tube by the exploding bolt.
(I)
(J)
In the event of the large torpedo being cut away in deep water after 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.
The brass guard for the exploding bolt is an extra precaution (suggested by Capt. A. Hood, R.N., Director-General of Naval Ordnance) should any person by mistake attempt to place the bolt into the torpedo without the safety key in its place. It is placed over the head of the bolt and pushed down until the thumb-screw on the side works into a small hole in the shoulder of the bolt.[1] The manner in which this guard is fitted ensures its removal before launching, since the after lever cannot be placed until it is. It also makes a convenient handle for turning the bolt in the magazine.
[1] As the certainty of explosion depends mainly upon the exploding bolt being properly charged, the inventor takes entire charge of this important detail.
(K)
The explosive composition in the bolts is powerful and safe; so packed that no amount of concussion can explode it; the bolt must be pierced through the capsule at the muzzle for that purpose. The bolts are hermetically sealed at the muzzle by a metallic capsule, and can be stored for an indefinite length of time without chance of deterioration. The exploding point of the composition in the bolt is 420° Fahrenheit.
(L)
The side and top levers are so arranged, that when driven close into the torpedo, the bolt is down to the shoulder; and, since there are three explosions to take place, it is calculated the torpedo will be in hugging contact when the main charge explodes, and exploded by a powerful discharge in the centre, thereby disposing of the explosive force to the greatest advantage.
The torpedo must be closing to the ship when the levers are acting and the bolt descending; no experiment for the force of explosive agents, with a cushion of water intervening, is required. The amount of explosive agent, when in contact, is all that is required, and the torpedo can be manufactured to contain a larger charge, if thought necessary, with a very small increase of dimensions; but the present size is convenient for handling and launching; and if loaded with any of the powerful blasting powders, would, in all probability, prove sufficient to bilge or destroy the largest iron-clad.
(M)
(N)
The lanyard or side-lever is permanently secured to the short arm of the lever; the end is rove under the fair lead on the deck of the torpedo up through the brass oval hole in the after top lever, then down under the fair lead (abaft the first turn), and across the deck of the torpedo to the handle, and secured with a round turn and two half-hitches. Care should be taken that the short arm of the lever is brought close into the fair lead, and the lanyard should be set up sufficiently taut to give a slight spring in the after top lever by the strain brought on it. This lever 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 one-eighth of an inch when the safety key is withdrawn, owing to the spring in the lever and shrinking of the lanyard; this brings the muzzle one-eighth of an inch nearer the pin without disturbing the side lever. The lanyard should be made up like a reef-point; it should be well-greased immediately before launching.
(O)
(P)
(Q)
To secure the fore top lever to the after, in order that a back hit may not separate them, the small lanyards, with an eye in one end, and whipped at the other, are first placed over the eyes in the fore top lever, then rove through the brass hole in the after top lever, in opposite directions, passed up through the eyes in the fore top lever, and knotted over it. The distance from the eyes in the fore top lever to the hole in the after top lever is so arranged that it will not interfere with the descent of them. The fore-locks for the various bolts which fix the levers are made of fishing-line. After knotting them, the ends should be secured together by a seizing of thread.
(R)
(S)
The handles, formed of iron straps passing under the torpedo, and terminating in four eyes above the deck, are principally for handling it; one of the foremost eyes is made use of as a fair lead for the safety-key lanyard, and to stop it to; the other foremost is made use of to secure the side lanyard to Fig. N ([p. 12]).
The ballast is composed of iron and sheet lead; the former, a fixture to the wooden bottom of the torpedo; the latter, screwed on with long screws into the iron. A thin sheet of lead is always kept on the bottom, affording a soft material for moving them about on, removing the objection that may be made to the friction caused by an iron bottom in the moving of them in the torpedo-room. By taking out these screws, several more thicknesses of sheet-lead can be screwed on, the same screws binding all together. On leaving the manufacturers, there is sufficient lead placed on the bottom for a speed between three and ten knots. A very large increase of ballast would require another buoy to be strung on over and above the usual complement.
(T)
The proper adjustment of the slings is most important, as the divergence depends upon it. The after legs of the slings, when stretched out alongside the torpedo, should extend one foot beyond the stem iron of the torpedo for the large torpedo, and eight inches for the small one; the distance on the slings being reckoned from the seizing round the thimble. This first adjustment is near enough if within two inches of the regulation.
The thimble of the slings is made suitable for wire or hemp rope, the fore surface of it being bell-mouthed, to prevent chafe of the tow-rope; the thimble is so constructed that the parts of the slings cannot escape from the groove should the seizing become slack; it will be observed that by this arrangement the edge of the thimble is not brought in contact when rounding the stem or stern of a vessel, the nip after leaving the tow-rope coming direct on to the fore span, and thence to the projecting curve of the side lever.
When all four legs are pulled out, in direction of the tow-rope, they bear an equal strain; the junction of the four legs should be on a level with the upper towing-irons, at the same time the upper fore span should make an angle between 80° and 85° with the near side of the torpedo. 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 slings are made of the best Italian hemp (not laid up too hard), the rope being of the same strength as the tow-rope; for although in towing four legs divide the strain, yet during collision the strain might be brought on one or two.[2]
[2] It may be here remarked, the small rudder on the stern of the torpedo is not for the purpose of increasing the divergence, but to control the direction of the torpedo when the tow-rope is suddenly slacked.
(U)
(V)
The tow-rope for large torpedo can be of 2½ in. or 3 in. hemp, or 1½ in. flexible galvanized iron wire. For small torpedo, 1½ in. to 2 in. hemp, or ⅞ in. wire.
The buoys are made of solid cork (such cork only being used as will ensure great floating power after being immersed for a time), it is built up on a galvanized iron tube, running longitudinally through; on the ends of the tube are screwed wooden cones, which bind all together and render the buoy indestructible. The iron tube gives great facility for stringing on the number of buoys required.
Drawing (W). Section on A B.
Two buoys are generally used for the large torpedo, and one for the small. The buoy-rope is of hemp, about five or six fathoms in length and two inches 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 the large or small ring in the stern (according to whether working in deep or shallow water), then through the tube of the first buoy, an overhand knot made in the rear; then through the next buoy, and a knot in the rear of that.
Drawing (X).
Drawing 1.
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 vessel, would be worked below the water-line to prevent exposure of the men. They are so arranged as to admit of the tow-rope being quickly veered, and at the same time powerful in bringing 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. The handles on the leather straps are for the purpose of lifting the strap off the drum when veering suddenly, that there may be no friction to interfere. The handles for winding up would rarely be used in real action, and never should be on when veering. 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 (see [Plate 2]). 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.
Drawing 2.
The drawing shows a small brake fitted for the electric torpedo, having a hollow central spindle, through which the end of the tow-rope carrying the insulated wire is rove, after passing out at the axle; a swivel connection is made with the battery. 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 light 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. The ordinary deep-sea lead line can be used for a safety-key line, or any hemp-rope from three-quarters to an inch circumference. It should be new and of good quality; for in the event of its carrying away before the stop, it would necessitate the recovery of the torpedo.
Drawing 3.
(Y)
The magazine for exploding bolts is fitted with exactly the same size brass tubing as in the priming case; therefore, if the bolts are kept to work with the proper pressure when in the magazine, they will do so in the torpedo. This magazine should be kept apart from the torpedo-room, and care should be taken that the tube is clear before forcing the loaded bolt into it. The torpedoes are then no more dangerous than any other powder case, and, being very strongly made and sealed, are probably less so.
Plate 2.
Kell Bros. Lith. London.