Driver-class sloop
The "Driver" class were a class of paddlewheel steam sloops of the British Royal Navy. Six "Driver"-class ships were ordered in 1840 and a further ten in March 1841, although only six were built. Five were ordered in 1847, but all were either built as paddle frigates or cancelled. Two wrecked in service, while the rest served until being retired and were either broken up or sold. Design. The ships were designed by Sir William Symonds. They were built of wood, displaced 1,590 tons and had a length on the gundeck of . Propulsion. Power was provided by  a two-cylinder direct-acting steam engine driving paddle wheels. "Spiteful" had a side-lever steam engine, "Devastation" had a 4-cylinder 'Siamese' steam engine and "Sphinx" had a 2-cylinder oscillating steam engine. The engines developed between 280 and 300 nominal horsepower, apart from "Devastation" (400 nhp) and "Sphinx" (500 nhp). All the ships were capable of about under steam, with the more powerful "Devastation" and "Sphinx" making 10 or 12 knots. A brig rig was fitted for operating under sail. Armament. All three ships were armed with two (84 cwt) guns on pivot mounts, two 68-pounder (64  cwt) guns and two 42-pounder (22 cwt) carronades. In 1856 the armament was changed to a single 10-inch pivot gun, a 68-pounder (95 cwt) gun and four 32-pounder (42 cwt) guns. Later, the 68-pounder was replaced by a 110 pdr Armstrong gun breech-loading gun. Crew. They had a complement of approximately 149 men, increasing later to 160. Construction. Six "Driver"-class ships were ordered in 1840 and a further ten in March 1841, although only six were built. Five were ordered in 1847, but all were either built as paddle frigates or cancelled. Driver-class