Ha-7-class submarine

The Ha-7-class submarine (波七型潜水艦, Ha-nana-gata sensuikan) was an early class of submarines of the Imperial Japanese Navy. It was also called the "Vickers C-3 class".^[1]

Japanese submarine Ha-7, in trials off Kure, 1916
Class overview
Builders	Kure Naval Arsenal, Japan
Operators	Imperial Japanese Navy
Preceded by	Ha-3 class
Succeeded by	Kaichū type
In commission	1916–1929
Completed	2
Retired	2
General characteristics
Type	Submarine
Displacement	286 long tons (291 t) surfaced 321 long tons (326 t) submerged
Length	43.3 m (142 ft 1 in)
Beam	4.14 m (13 ft 7 in)
Draft	3.43 m (11 ft 3 in)
Installed power	600 hp (450 kW) (gasoline engines) 300 hp (220 kW) (electric motors)
Propulsion	Gasoline engines Electric motors 1 shaft
Speed	12 knots (22 km/h; 14 mph) surfaced 7 knots (13 km/h; 8.1 mph) submerged
Range	660 nmi (1,220 km; 760 mi) at 12 knots (surfaced) 60 nmi (110 km; 69 mi) at 8.5 knots (15.7 km/h; 9.8 mph) (submerged)
Test depth	30.5 m (100 ft)
Complement	26 officers and enlisted
Armament	4 × 18 in (460 mm) bow torpedo tubes (4 × torpedoes) 1 × machine gun

Background

A final two vessels of the British C-class submarine design were built completely in Japan by the Kure Naval Arsenal as part of the emergency expansion of the Imperial Japanese Navy due to World War I. Although the design was considered obsolete by this time, these vessels were felt necessary to meet the perceived threat of German submarine activity in Japanese coastal waters. Physically almost identical to the Ha-3 class, the two vessels incorporated a number of improvements, including a change in the location of the rudder for better control, and the addition of two externally mounted torpedo tubes to double the attack capability from previous designs. Arriving in Japan during the closing stages of the war, neither vessel was ever used in combat.

Ships in class

• Japanese submarine Ha-7 (波号第七潜水艦, Ha-go Dai-nana sensuikan), laid down 1 August 1916; launched 15 March 1916; commissioned 1 November 1916 as 2nd Class Submersible No.16; reclassified as 3rd class submarine on 1 April 1919; renamed Ha-7 on 15 June 1923, decommissioned on 1 December 1929.^[2]
• Japanese submarine Ha-8 (波号第八潜水艦, Ha-go Dai-hachi sensuikan), laid down 1 August 1916; launched 15 March 1916; commissioned 2 February 1917 as 2nd Class Submersible No.17; reclassified as 3rd class submarine on 1 April 1919; renamed Ha-8 on 15 June 1923; decommissioned on 1 December 1929.^[2]