Sokuten-class minelayer (1938) explained

The was a class of minelayers of the Imperial Japanese Navy (IJN), serving during and after World War II. The class consists of three subclasses, which this article handles collectively.

Background

• In 1937, the IJN planned this class as a replacement for the timeworn Natsushima and the Sokuten-class auxiliary minelayer.

Ships in classes

Sokuten class

• Project number H11. Original model of the Sokuten class. Five vessels were built in 1937–40 under the Maru 3 Programme (Ship # 57–61).

Ship #	Ship	Builder	Laid down	Launched	Completed	Fate
57		Mitsubishi, Yokohama Shipyard	24-06-1937	27-04-1938	28-12-1938	Sunk by aircraft at Palau, 25-07-1944.
58		Tōkyō Ishikawajima Shipyard	03-09-1937	25-06-1938	25-04-1939	Clashed with Army troop transport and sunk off Urup, 03-03-1944.
59		Mitsubishi, Yokohama Shipyard	24-03-1939	28-08-1939	20-06-1940	Sunk by USS Sennet off Kii Peninsula 32.1667°N 193°W, 16-02-1945.
60		Tōkyō Ishikawajima Shipyard	22-06-1938	29-06-1939	27-12-1939	Decommissioned on 05-09-1945. Surrendered to United Kingdom on 20-11-1947. Scrapped on 31-03-1948.
61		Tōkyō Ishikawajima Shipyard	28-07-1939	09-12-1939	31-10-1940	Sunk by unknown submarine off Hatsushima, 16-11-1943.

Hirashima class

• Project number H11B. Second production model of the Sokuten-class. Nine vessels were built in 1939–43 under the Maru 4 Programme (Ship # 170–178). They were equipped with a 76.2 mm anti-aircraft gun. The Nuwajima had its ballast tank replaced with a fuel tank for convoy escort operations. These nine vessels were classed in the Sokuten-class in the IJN official documents.

Ship #	Ship	Builder	Laid down	Launched	Completed	Fate
170		Mitsubishi, Yokohama Shipyard	06-09-1939	06-06-1940	24-12-1940	Sunk by USS Sawfish at west of Gotō Islands, 27-07-1943.
171		Tama Shipyards	07-11-1940	08-09-1941	20-12-1941	Sunk by aircraft off Buka Island, 28-09-1943.
172		Mitsubishi, Yokohama Shipyard	10-03-1941	13-08-1941	28-02-1942	Decommissioned on 30-11-1945. Surrendered to United States on 01-10-1947. Sunk as target at 35.6667°N 175°W on 16-10-1947.
173		Nihon Kōkan, Tsurumi Shipyard	11-12-1940	18-10-1941	25-03-1942	Sunk by aircraft at Okinawa Island, 10-10-1944.
174		Ōsaka Iron Works, Sakurajima Factory	15-01-1941	15-11-1941	25-04-1942	Decommissioned on 22-10-1945. Surrendered to Republic of China on 03-10-1947, and renamed Yungtsin (PF-75). Decommissioned on 01-05-1960.
175		Mitsui, Tamano Shipyard	12-07-1941	02-03-1942	31-08-1942	Struck a naval mine at Muroran on 04-10-1945. Decommissioned on 05-10-1945. Scrapped 1947.
176		Nihon Kōkan, Tsurumi Shipyard	31-10-1941	04-07-1942	25-11-1942	Sunk by USS Cobia off Kota Bharu, 14-01-1945.
177		Ōsaka Iron Works, Sakurajima Factory	26-11-1941	31-07-1942	15-11-1942	Heavy damaged by aircraft at Saiki, 30-04-1945. Later sank in shallow water. Salvaged and scrapped on 01-09-1948.
178		Nihon Kōkan, Tsurumi Shipyard	20-07-1942	18-04-1943	31-07-1943	Sunk by aircraft at Laoag City, 21-10-1944.
179		Hitachi Zōsen				Cancelled on 11 August 1943.^[1]

Ajiro class

• Project number H13 at first. The IJN hoped urgent building for her. The Navy Technical Department revised the Hirashima drawings. Twenty-six vessels were planned under the Maru Kyū Programme (Ship # 460–473, 14 vessels) and the Kai-Maru 5 Programme (Ship # 5421–5432, 12 vessels), but only Ajiro was completed. The Ajiro-class were classified separately from the Sokuten-class in the IJN official documents.

Ship #	Ship	Builder	Laid down	Launched	Completed	Fate
460		Hitachi Zōsen, Innoshima Shipyard	06-09-1943	08-04-1944	31-07-1944	Sunk by USS Snapper at northwest of Chichi-jima, 01-10-1944.
461–473						Cancelled on 11 August 1943.
5421–5432						Cancelled on 5 May 1944.^[2]

Bibliography

• Web site: Rekishi Gunzō., History of Pacific War Vol.51, The truth histories of the Imperial Japanese Vessels Part.2, Gakken (Japan), June 2002,
• Ships of the World special issue Vol.45, Escort Vessels of the Imperial Japanese Navy, Web site: Kaijinsha., (Japan), February 1996
• Model Art Extra No.340, Drawings of Imperial Japanese Naval Vessels Part-1, Web site: Model Art Co. Ltd. . 2009-05-13 . 2012-06-05 . https://web.archive.org/web/20120605034808/http://www.modelart.jp/ . dead . (Japan), October 1989
• The Maru Special, Japanese Naval Vessels No.47, Japanese naval mine warfare crafts, Web site: Ushio Shobō. (Japan), January 1981
• Daiji Katagiri, Ship Name Chronicles of the Imperial Japanese Navy Combined Fleet, Kōjinsha (Japan), June 1988,
• Senshi Sōsho Vol.31, Naval armaments and war preparation (1), "Until November 1941", Asagumo Simbun (Japan), November 1969
• Senshi Sōsho Vol.88, Naval armaments and war preparation (2), "And after the outbreak of war", Asagumo Simbun (Japan), October 1975

Notes and References

1. Senshi Sōsho Vol.88 (1975), p.71 - 74
2. Senshi Sōsho Vol.88 (1975), p.95