Arashio alongside in Apra Harbor on 1 April 1984
Class overview
Name	Asashio class
Builders	Kawasaki Shipbuilding Corporation, Mitsubishi Heavy Industries
Operators	Japan Maritime Self-Defense Force
Preceded by	Ōshio class
Succeeded by	Uzushio class
Built	1964−1969
In commission	1966−1986
Planned	4
Completed	4
Retired	4
General characteristics
Type	Submarine
Displacement	1,650 long tons (1,680 t) surfaced 2,150 long tons (2,180 t) submerged
Length	88 m (288 ft 9 in)
Beam	8.2 m (26 ft 11 in)
Draft	4.9 m (16 ft 1 in)
Propulsion	Kawasaki Diesel-electric, 2 shafts 2,900 bhp (2,200 kW) (surfaced) 6,300 shp (4,700 kW) (submerged)
Speed	14 knots (26 km/h; 16 mph) surfaced 18 knots (33 km/h; 21 mph) submerged
Complement	80
Armament	4 × bow 533 mm (21 in) torpedo tubes 2 × stern 320 mm (12.7 in) torpedo tubes

The Asashio-class submarine is a submarine class of Japanese Maritime Self-Defense Force comprising four boats. This class is the successor of Ōshio. The class were the first fleet submarines constructed for post-war Japan. The first submarine was authorized as part of the 1963 shipbuilding programme. Their design improved on previous Japanese classes by being larger to obtain better seaworthiness with greater torpedo stowage. The class entered service in the late 1960s and remained as such until the mid-1980s when they were taken out of service.

Design and description

Based on the preceding Ōshio, the Asashio class were of similar design but with a different shaped bow and improved sonar. They are considered the first fleet submarines constructed for Japan in the post-World War II era.^[1] The submarines, constructed with a double hull,^[2] measured 88 meters (288 ft 9 in) long with a beam of 8.2 m (26 ft 11 in) and a draft of 4.9 m (16 ft 1 in). The vessels had a standard displacement of 1,650 long tons (1,680 t) surfaced and a submerged displacement of 2,150 long tons (2,180 t).^[1] The Asashio class had a complement of 80.^[3] The Asashio class were propelled by two propellers powered by a diesel-electric system comprising two Kawasaki diesel engines creating 2,900 brake horsepower (2,200 kW) and two electric motors creating 6,300 shaft horsepower (4,700 kW). This gave the submarines a maximum speed of 14 knots (26 km/h; 16 mph) submerged and 18 knots (33 km/h; 21 mph) while surfaced.^[3]

The vessels were equipped with eight torpedo tubes, six in the bow and two in the stern.^[1][3] The sources disagree on the torpedo armament, with two sources stating that all eight were for 533-millimeter (21.0 in) torpedoes,^[1][3] while another states that only the forward six were for the 533 mm torpedoes and the stern tubes were for 320 mm (12.7 in) torpedoes.^[2] Moore^[2] and Gardiner, Chumbley and Budzbon^[1] state that the stern tubes were for "swim-out" torpedoes with Gardiner, Chumbley and Budzbon adding they were for anti-submarine warfare (ASW) and that the forward tubes were intended for US Mark 54 torpedoes.^[1] They carried a total of 20 torpedoes.^[4] The Asahio class mounted ZPS-3 radar, SQS-4 active sonar and JQS-3A and JQQ-2A passive sonars. They were also equipped with BLR-1 intercept equipment.^[3]

Boats

Construction and career

The first submarine Asashio was ordered as part of the 1963 shipbuilding programme.^[2] Construction was split between the Kawasaki and Mitsubishi yards at Kobe. The submarines were used for ASW training for surface ships in naval exercises. The class was deleted in the mid-1980s.^[1][4]