Natsushio-class submarine

The Natsushio-class submarines were significantly smaller than the next generation Japanese submarines, Ōshio, and the Natsushio-class submarines were the development of the Hayashio-class submarines. Also, the Natsushio class is one of the (coast-defence) hunter-killer submarine (SSK) of JMSDF. Construction of the two subs in the class was approved under the First Defense Buildup Program 1958-1960. However, the MSDF brass did not welcome the small submarines. Ongoing maneuvering regarding defense spending by the Ministry of Finance did not help matters. At the time, the Maritime Staff Office was trying to move the MSDF away from being a predominantly green-water navy (due to politics and budgetary issues this would not begin to happen until the 1980s). Small coastal SSKs like the Natsushios did not fit into such plans for the future. Therefore, neither further examples nor a successor class were built.

JS Fuyushio (SS-524)
Class overview
Name	Natsushio
Builders	New Mitsubishi Heavy Industries, Kawasaki Shipbuilding Corporation
Operators	Japan Maritime Self-Defense Force
Preceded by	Hayashio class
Succeeded by	Ōshio class
Built	1961–1963
In commission	1963–1980
Planned	2
Completed	2
Retired	2
General characteristics
Type	Coastal attack submarine
Displacement	790 long tons (803 t) surfaced
Length	61 m (200 ft 2 in)
Beam	6.5 m (21 ft 4 in)
Draft	4.1 m (13 ft 5 in)
Depth	6.4 m (21 ft 0 in)
Propulsion	Diesel-electric, 2 shafts 900 bhp (670 kW) (surfaced) 2,300 shp (1,700 kW) (submerged)
Speed	11 knots (20 km/h; 13 mph) surfaced 15 knots (28 km/h; 17 mph) submerged
Complement	40
Armament	3 × 533 mm (21 in) torpedo tubes