Tsukushi-class survey ship

The Tsukushi class was a class of auxiliary survey ships of the Imperial Japanese Navy in World War II, made up of two subclasses that the article treats together, the Tsukushi class itself and the planned Miho class. Since the Meiji period the navy had carried out hydrographic survey with old warships, which were too slow for combat zones and could not carry many survey instruments, and by the 1930s the navy saw that it needed purpose-built survey ships. After a 1930 proposal failed, a budget for one 1,400-ton ship was granted in 1937 as Project J11, named Tsukushi. She had armament and handling like a later escort ship, carried a floatplane for aerial survey, and had three shafts so that the centre shaft alone could drive her at a minimum cruising speed of 2.2 knots. Tsukushi was completed in December 1941 and sank on a magnetic mine off Kavieng in 1943. The second ship, Miho, was cancelled in 1944. Mitsubishi Heavy Industries built Tsukushi at its Yokohama shipyard.