Asashio-class submarine

The Asashio-class submarine is a submarine class of Japanese Maritime Self-Defense Force comprising four boats. This class is the successor of JDS 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 JDS 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. The submarines, constructed with a double hull, measured 88 m long with a beam of 8.2 m and a draft of 4.9 m. The vessels had a standard displacement of 1650 LT surfaced and a submerged displacement of 2150 LT. The Asashio class had a complement of 80. The Asashio class were propelled by two propellers powered by a diesel-electric system comprising two Kawasaki diesel engines creating 2900 bhp and two electric motors creating 6300 shp. This gave the submarines a maximum speed of 14 kn submerged and 18 kn while surfaced.

The vessels were equipped with eight torpedo tubes, six in the bow and two in the stern. The sources disagree on the torpedo armament, with two sources stating that all eight were for 533 mm torpedoes, while another states that only the forward six were for the 533 mm torpedoes and the stern tubes were for 12.7 in torpedoes. Moore and Gardiner, Chumbley and Budzbon 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. They carried a total of 20 torpedoes. 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.

Construction and career
The first submarine Asashio was ordered as part of the 1963 shipbuilding programme. 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.