Sokuten-class auxiliary minelayer (1913)

Kurosaki in 1934
Class overview
Name:	Natsushima Sokuten class auxiliary minelayer
Builders:	Kure Naval Arsenal Maizuru Naval Arsenal Uchida Zōsen Yokohama Iron Works Yokohama Dock Company
Operators:	Imperial Japanese Navy Japan Maritime Safety Agency Republic of China Navy Soviet Navy People's Liberation Army Navy
Succeeded by:	Tsubame class
Built:	? – 1921
In commission:	1911 – 1970
Planned:	13
Completed:	13
Lost:	4
Retired:	9
General characteristics Natsushima
Type:	Minelayer
Displacement:	405 long tons (411 t) standard
Propulsion:	2 × three expansion stages reciprocating engines 1 × water tube boiler 2 shafts, 600 shp
Complement:	40
Armament:	2 × Armstrong 3 in L/40 guns
General characteristics Sokuten class
Type:	Minelayer
Displacement:	405 long tons (411 t) standard
Length:	45.7 m (149 ft 11 in) Lpp
Beam:	7.6 m (24 ft 11 in)
Draught:	2.3 m (7 ft 7 in)
Propulsion:	2 × three expansion stages reciprocating engines 2 shafts, 600 shp Enoshima and Kurosaki 1 × Ikeda model water tube boiler all others 1 × Kampon water tube boiler
Speed:	12.0 knots (13.8 mph; 22.2 km/h)
Endurance:	Fuel:[1] Sokuten and Toshima 30 tons coal Kuroshima, Ashizaki, Katoku and Entō 60.5 tons coal and after the Kurokami 70 tons coal
Complement:	40
Armament:	Sokuten 2 × Armstrong 3 in L/40 guns all others 1 × Type 41 76.2 mm (3.00 in) L/40 naval gun 82 × Mk.5 naval mines 18 × depth charges Kurosaki, 1945 1 × Type 41 76.2 mm L/40 gun 2 × Type 93 13 mm AA guns ? × naval mines ? × depth charges 2 × depth charge projectors

The Sokuten class auxiliary minelayer (測天型敷設特務艇,, Sokuten-gata Fusetsu-Tokumutei) was a class of minelayers of the Imperial Japanese Navy (IJN), serving during the 1910s and World War II. They were called the Sokuten class from their nameship. And, they were called Toshima class after the Sokuten retired. Also, by the book, the Natsushima was included to this class. This article handles the Natsushima and Sokuten class collectively, because they do not have a big difference. Their official class name was not mentioned in the IJN official documents.

Background

• The IJN intended to update their mineboats for local guards.

Construction

• In 1911, the IJN built the first experimental boat Natsushima (Natsushima Maru). The Natsushima attached importance to gun-fights. Therefore, she was equipped with two 3 inches Armstrong guns.
• In 1913, the IJN built the second experimental boat Sokuten (Sokuten Maru No. 1). She was improved model of the Natsushima, and her equipments were almost the same as Natsushima.
• The IJN adopted Sokuten's hull designs, and started productions.
• Kuroshima, Kurokami and Kurosaki were equipped netlayer facilities. However, those armaments were not announced.

Service in the World War II

• Natsushima was retired in 1927, and Sokuten was retired in 1936.
• The other sisters participated to World War II, and 9 boats survived war.

Ships in class

Photos

• 
  Natsushima (as Natsushima Maru) on 10 October 1912
• 
  Enoshima in 1930

Footnotes

Bibliography

• "Rekishi Gunzō". , History of Pacific War Vol. 51, "The truth histories of the Imperial Japanese Vessels Part-2", Gakken (Japan), June 2002, ISBN 4-05-602780-3
• Ships of the World special issue Vol. 45, Escort Vessels of the Imperial Japanese Navy, "Kaijinsha". , (Japan), February 1996
• The Maru Special, Japanese Naval Vessels No. 47, "Japanese naval mine warfare crafts", "Ushio Shobō".  (Japan), January 1981
• Editorial Committee of the Navy, Navy Vol. 11, "Part of small vessels, auxiliary vessels, miscellaneous service ship and converted merchant ships, Seibunsha K.K. (Japan), August 1981