 Captain-Ret Seki Tei (former CO of "Santo Maru") was posted as the Chief Equipping Officer of IJN submarine tender "Tsukushi Maru" on 15 January 1943.Tei Seki was killed in action 31 January 1944 when converted submarine tender was torpedoed.On 24 January 1944, "Yasukuni Maru" was assigned to a troop convoy departing Tateyama, Chiba for Truk.