Vesuvius was intended for night attacks against enemy harbours, and was armed with a single tube for Whitehead torpedoes in her bow.

From 1864, the English engineer Robert Whitehead, based at Fiume in the Austrian empire (now Rijeka in Croatia), began work on a self-propelled, or "locomotive" torpedo which would run underwater, powered by compressed air.

After trials from the sloop Oberon in September–October 1868, the Admiralty purchased a license to build Whitehead's torpedo, with production beginning at the Royal Arsenal at Woolwich, London in 1872.

The ship was powered by compound steam engines rated at 382 indicated horsepower (285 kW) which drove two propeller shafts, giving a speed of 9.7 knots (11.2 mph; 18.0 km/h).

The Queen recorded in her Journal that she was impressed by the 2 torpedo boats, Vesuvius & Lightning, which rushed about at the rate of 20 Knots an hour.

[12] Vesuvius was not seriously evaluated against her design role of night torpedo attacks and was too slow and had too short a range to accompany the fleet.