Hydra-class sloop

Wreck of HM Steam-Sloop Hecla off Gibraltar Illustrated London News
Class overview
Name:	Hydra-class steam sloop
Builders:	Chatham Dockyard
Operators:	Royal Navy
Preceded by:	HMS Gorgon
Succeeded by:	Merlin-class sloop
Cost:	Hydra: £37,239
Built:	1837–1839
In commission:	1838–1870
Completed:	3
Retired:	3
General characteristics
Type:	Second-class steam vessel (later second class sloop)
Displacement:	1,096 long tons (1,114 t)
Tons burthen:	814 91/94 tons bm
Length:	165 ft 0 in (50.3 m) (gundeck) 143 ft 7 1⁄4 in (43.8 m) (keel)
Beam:	32 ft 10 in (10.0 m)
Draught:	12 ft 1 in (3.7 m) (forward) 13 ft 0 in (4.0 m) (aft)
Depth of hold:	20 ft 4 in (6.2 m)
Installed power:	Hydra: 220 nhp Hecla & Hecate: 240 nhp
Propulsion:	Hydra: Boulton and Watt side-lever steam engine Iron tubular boilers Side paddles Hecla & Hecate: Sinclair & Scott side-lever steam engine Iron tubular boilers Side paddles
Sail plan:	Brig rig
Speed:	9 knots (17 km/h) (under steam)
Complement:	135
Armament:	2 × 32-pounder (50 cwt) guns 2 × 8-inch (204 mm) 65 cwt pivot guns

The Hydra class were a class of three paddlewheel steam sloops of the British Royal Navy. They saw active service variously in the Baltic during the Crimean War, against Ottoman forces in Syria and against slavers in West Africa. Latterly Hydra and Hecate were used for survey in the Mediterranean, the Pacific, Australia and the Atlantic, and thus their names were re-used for the Hecla-class survey vessels in the late 20th century. Two of the class were broken up after more than twenty-five years of service, and Hecla was sold for commercial use in 1863.

The ships were designed by Sir William Symonds and were approved on 3 November 1837. They were built of wood, displaced 1,096 tons and had a length on the gundeck of 165 feet (50.3 m).

Power was provided by a two-cylinder side-lever steam engine driving paddle wheels. In Hecla and Hecate this engine was provided by Scott & Sinclair, and was rated at 240 nominal horsepower; in Hydra the steam engine was provided by Boulton and Watt and rated at 220 nominal horsepower. All the ships were capable of about 9 knots (17 km/h) under steam. Paddle sloops of the period were usually built with a schooner rig, but later pictures show Hecate with a brig rig.

Hecla had her engines replaced in her 1848-1849 refit.

All three ships were armed with two 32-pounder (50 cwt) smoothbore muzzle-loading guns on truck mounts and two 8 in (200 mm) (65 cwt) smoothbore muzzle-loading shell guns on pivoting mounts.

They had a complement of approximately 135 men.

Hecate served in the Mediterranean from 1840 to 1843, including operations against the Ottomans in Syria in 1840. From 1845 to 1857 she served off the west coast of Africa, including anti-slavery operations. In 1860 she became a survey vessel, and under George Henry Richards she made a survey of Vancouver Island.