A twin-screw steam launch (length 42 feet, beam 10 feet 11 inches, draught 1 foot 11 inches forward and 3 feet and one half of an inch aft, displacement 10 and 3 quarter tons; trial speeds 7.9 knots (non-condensing) at 326 revolutions per minute and 8.1 knots (condensing) at 328.5 revolutions per minute); built by J and G Rennie, London. In 1865 Messrs. Penn, Maudslay and Rennie were asked to design engines suitable for installation in the ship's launches of the Royal Navy. However, the designs submitted by Messrs. Penn and Maudslay did not differ greatly from those of Mr. A. Murray the Chief Engineer of the Portsmouth Dockyard, who was said to have been responsible for fitting the first steam engines in a ship's launch, these engines were very similar to the small locomotive or agricultural engines in use at the time.