British G-class submarine

G9
Class overview
Name	G class
Builders	HM Dockyard, Chatham Armstrong Whitworth, Newcastle upon Tyne Vickers, Barrow-in-Furness Scott's, Greenock
Operators	Royal Navy
Built	1914-1917
In service	1915-1921
Completed	14
Cancelled	1
Lost	4
Scrapped	10
General characteristics
Type	Submarine
Displacement	703 long tons (714 t) surfaced 837 long tons (850 t) submerged
Length	187 ft 1 in (57.0 m)
Beam	22 ft 8 in (6.9 m)
Draught	13 ft 4 in (4.1 m)
Installed power	1,600 bhp (1,200 kW) (diesel) 840 hp (630 kW) (electric motor)
Propulsion	2 × Vickers diesel engines 2 × electric motors
Speed	14.25 knots (26.39 km/h; 16.40 mph) surfaced 9 knots (17 km/h; 10 mph) submerged
Range	2,400 nmi (4,400 km; 2,800 mi) at 12.5 kn (23.2 km/h; 14.4 mph) surfaced
Complement	30
Armament	4 × 18-inch (45 cm) torpedo tubes 1 × 21-inch (53.3 cm) torpedo tube 1 × 3-inch (7.6 cm) deck gun

The G-class were a series of diesel-electric submarines of the Royal Navy in World War I

They were launched between 1914 and 1917, and intended for operations in the North Sea and German Bight against German U-boats.