Mermaid-class destroyer

Two Mermaid-class destroyers served with the Royal Navy during the First World War.[2] They were three-funnelled turtle-backed destroyers with the usual Hawthorn funnel tops. Built in 1896–1898, Mermaid and Cheerful were launched by R. & W. Hawthorn, Leslie & Company from their Hebburn-on-Tyne shipyard.

The visually identical Greyhound underway in 1906
Class overview
Name	Mermaid class
Operators	Royal Navy
Built	1896–1898
In commission	1897–1919
Completed	2
Lost	1
Scrapped	1
General characteristics
Type	Destroyer
Displacement	385 long tons (391 t) light 430 long tons (437 t) full load
Length	214 ft 6 in (65.38 m) overall
Beam	21 ft 1 in (6.43 m)
Draught	13 ft (4.0 m)
Propulsion	2 shaft reciprocating engines 4 Thornycroft boilers[1] 6,100 shp (4,549 kW)
Speed	30 knots (56 km/h; 35 mph)
Complement	62
Armament	1 × QF 12 pounder 12 cwt gun 2 × 18-inch (457 mm) torpedo tubes (2×1)

Their Thornycroft boilers produced 6,100 hp to given them the required 30 knots (56 km/h) and they were armed with the standard 12-pounder gun and two torpedo tubes. They carried a complement of 63 officers and men. In 1913 the pair - like all other surviving three-funnelled destroyers of the "30-knotter" group - were reclassed as C-class destroyers. The almost identical Greyhound-class ships built subsequently at the same yard differed only by having Yarrow boilers.