Steam gun boat

Grey Goose
Class overview
Name	Steam gun boat (SGB)
Operators	RN
Built	1940–1942
In service	Nov 1941- post-war
Planned	52
Completed	7
Cancelled	2
Lost	1
General characteristics
Displacement	175 tons (standard), 255 tons (deep load)
Length	44.3 m (145 ft 8 in) overall
Beam	6.1 m (20 ft)
Draught	1.68 m (5 ft 6 in)
Installed power	8,000 shp (5,965 kW)
Propulsion	1 × LaMont boiler 2 × Metropolitan-Vickers geared Steam turbines 2 × shafts
Speed	35 kn (65 km/h) maximum
Range	200 NM (370 km) at full speed 900 NM (1,700 km) at 12 knots
Complement	27 initially (3 officers and 24 men), later rising to 34 as a result of changes in armament
Armament	Final arrangement: 1 × 3-in (76.2 mm) gun 2 × single 6-pdr guns 2 × twin 20-mm Oerlikon cannon 2 × 21-inch torpedo tubes

Steam gun boats (SGBs) were small Royal Navy vessels built from 1940 to 1942 for Coastal Forces during World War II. The class consisted of nine steam-powered torpedo boats.

They were developed in parallel with the 35-metre long Fairmile D motor torpedo boats ("dog boats"), specifically due to the need to hunt down German E-boats at a time of scarcity of suitable diesel engines. While sixty were planned, only an initial batch of nine were ordered on 8 November 1940, of which seven were completed.