Sokuten-class auxiliary minelayer (1913)

The Sokuten class auxiliary minelayer (測天型敷設特務艇,) 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.