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:—