HMS J7

	HMAS J7
History
United Kingdom
Name	HMS J7
Builder	HM Dockyard, Devonport
Launched	12 February 1917
Fate	Transferred to Australia, 25 March 1919
Australia
Name	HMAS J7
Acquired	25 March 1919
Decommissioned	12 July 1922
Fate	Sunk 4 June 1926
Notes	Still extant as breakwater as of 2021
General characteristics
Class and type	British J class submarine
Displacement	1,210 long tons (1,230 t) (surfaced); 1,760 long tons (1,790 t) (submerged);
Length	275 ft (84 m)
Beam	22 ft (6.7 m)
Draught	14 ft (4.3 m)
Propulsion	Three shafts; Surfaced: three 12-cylinder diesel engines; Submerged: battery-driven electric motors;
Speed	19 kn (35 km/h; 22 mph) (surfaced); 9.5 kn (17.6 km/h; 10.9 mph) (submerged);
Range	4,000 nmi (7,400 km; 4,600 mi) at 12 kn (22 km/h; 14 mph)
Test depth	300 ft (91 m) max[citation needed]
Complement	44 personnel
Armament	six 18 inch (450 mm) torpedo tubes; (four bow, two beam); one 4 in (102 mm) gun;

HMS J7 (later HMAS J7) was a J-class submarine operated by the Royal Navy and the Royal Australian Navy.