Natsushio-class submarine

The Natsushio-class submarines were a pair of submarines constructed and operated by the Japan Maritime Self-Defense Force during the Cold War. They were a development of the Hayashio-class submarines and are sometimes considered the same class. They were small and limited in capability but were thought to be a successful class. They entered service in 1963–1964 and were deleted in 1978.

JS Fuyushio
Class overview
Name	Natsushio class
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	1963–1978
Planned	2
Completed	2
Retired	2
General characteristics
Type	Coastal attack submarine
Displacement	690 long tons (701 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)
Propulsion	Sulzer-Mitsubishi Diesel-electric, 2 shafts 1,350 bhp (1,010 kW) (surfaced) 2,300 shp (1,700 kW) (submerged)
Speed	12 knots (22 km/h; 14 mph) surfaced 15 knots (28 km/h; 17 mph) submerged
Complement	43
Armament	3 × 533 mm (21 in) torpedo tubes

Design and description

The Natsushios were a development of the preceding Hayashio class and are sometimes considered the same class.^[1][2][3] They shared many of the same characteristics with small design improvements. They were small submarines with limited capability^[1] but considered handy and a successful class.^[4] They were air-conditioned and had good habitability for the crews. The submarines measured 61 meters (200 ft 2 in) long overall with a beam of 6.5 m (21 ft 4 in) and a draft of 4.1 m (13 ft 5 in). The submarines had a standard displacement of 780 long tons (790 t), with a surfaced displacement of 690 long tons (700 t) and 850 long tons (860 t) submerged.^[1][3]

The vessels were powered by a diesel-electric system. Two shafts were powered by two Sulzer-Mitsubishi diesel engines creating 1,350 brake horsepower (1,010 kW) and two electric motors creating 1,700 shaft horsepower (1,300 kW). This gave the submarines a maximum speed of 12 knots (22 km/h; 14 mph) surfaced and 15 knots (28 km/h; 17 mph) submerged.^[1][a] The Natsushios were armed with three 533-millimeter (21 in) torpedo tubes in the bow. They had a crew of 43.^[1]

Boats in class

Natsushio class construction data[1]
Pennant no.	Name	Laid down	Launched	Commissioned	Fate
SS-523	Natsushio (なつしお)	5 December 1961	18 September 1962	29 June 1963	Deleted 20 March 1978
SS-524	Fuyushio (ふゆしお)	6 December 1961	14 December 1962	17 September 1963	Deleted 20 June 1978

See also

• Quebec-class submarine - Soviet Navy
• Draken-class submarine - Royal Swedish Navy
• Toti-class submarine - Italian Navy
• Ro-100-class submarine - Imperial Japanese Navy
• Ha-201-class submarine - Imperial Japanese Navy

Notes

1. Blackman^[2] and Moore^[4] have the submarines' surfaced speed as 11 knots (20 km/h; 13 mph).