Operation Tatsumaki


'Tatsumaki' was the Japanese submarine component of the 'Yu' plan to decimate the US Fast Carrier Task Force in the lagoon of Majuro atoll in the Marshall islands group (May 1944).

At Nasake Jima, an island of the Inland Sea, Vice Admiral Takeo Takagi, commander of the 6th Fleet, supervised the preparation of the undertaking on board the 2,417-ton submarine tender Tsukushi Maru, and concentrated a force of five submarines and 14 carrier vehicles on the small Nasake Jima. Several support vessels and a 30-ton floating crane arrived from Kure in Japan to facilitate the loading of the tanks aboard the submarines. Each of the five submarines carried two carrier vehicles and practised crash-dives, full-speed underwater manoeuvres, launch exercises and torpedo attacks.

The submarines at the centre of this part of the plan’s components were I-36, I-38, I-41, I-44 and I-53, each carrying two Type 4 'Ka-Tsu' amphibious carrier vehicles on its after deck. The Type 4 was equipped to carry and launch 450-mm (17.7-in) Type 2 surface-launched torpedoes.

On 26 March 1944, I-36 left Kure for a preliminary reconnaissance of Majuro, and this was undertaken on 22 April, the submarine’s Yokosuka E14Y1 'Glen' floatplane reporting the presence of 11 carriers and three battleships.

'Tatsumaki' fell into abeyance with the demise of the 'Yu' plan.