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.