In the final two years of World War II, the Imperial Japanese Army constructed transport submarines — officially the Type 3 submergence transport vehicle and known to the Japanese Army as the Maru Yu — with which to supply its isolated island garrisons in the Pacific Ocean. Only submarines of the Yu I type were completed and saw service. The Yu I type was produced in four subclasses, each produced by a different manufacturer and differing primarily in the design of their conning towers and details of their gun armament. None carried torpedoes or had torpedo tubes. Yu 7 was a unit of the Yu 1 subclass.[1]
The Hitachi Kasado Works (Hitachi Kasado Seisakujo) at Kudamatsu, Japan, constructed Yu 7.[1][2] Records of the details of the construction of Yu 7 have not been discovered, but the earlier Yu I-type submarines were laid down and launched during the latter half of 1943 and entered service at the end of 1943 or early in 1944.[2][3]
Service history
Yu 7 spent her operational career in Japanese home waters.[4] She was assigned to Detachment 2, Transport Submarine Group, in November 1944.[citation needed] In January 1945, several Type I transport submarines were sent to operate from Shimoda on the southern tip of the Izu Peninsula in Shizuoka Prefecture on Honshu,[4] and the submarines began transport missions from Shimoda in March 1945.[4] It is not clear when Yu 7 began operations from Shimoda, but she made a round-trip supply voyage from Shimoda to Hachijō-jima in the Philippine Sea sometime during 1945 as well as a round-trip supply voyage from the Army Transport Submarine Base on the Seto Inland Sea at Mishima in Ehime Prefecture[5] on Shikoku in Japan to Ōshima Island in March 1945.[2][4]
Bailey, Mark L. (1998). "Imperial Japanese Army Transport Submarines: Details of the YU-2 Class Submarine YU-3". Warship International. XXXV (1): 55–63.
Carpenter, Dorr B. & Polmar, Norman (1986). Submarines of the Imperial Japanese Navy 1904–1945. London, England: Conway Maritime Press. ISBN0-85177-396-6.
Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. London, England: Conway Maritime Press. ISBN0-85177-146-7.
Mühlthaler, Erich (1998). "Re:Imperial Japanese Army Transport Submarines". Warship International. XXXV (4): 329–330. ISSN0043-0374.
Rekishi Gunzō, History of Pacific War Extra, Perfect guide, The submarines of the Imperial Japanese Forces, Gakken, Tokyo Japan, 2005, ISBN4-05-603890-2.
Rekishi Gunzō, History of Pacific War Vol.45, Truth histories of the Imperial Japanese Naval Vessels, Gakken, Tokyo Japan, 2004, ISBN4-05-603412-5.
Ships of the World No.506, Kaijinsha, Tokyo Japan, 1996.
The Maru Special, Japanese Naval Vessels No.43 Japanese Submarines III, Ushio Shobō, Tokyo Japan, 1980.
Atsumi Nakashima, Army Submarine Fleet, "The secret project !, The men challenged the deep sea", Shinjinbutsu Ōraisha, Tokyo Japan, 2006, ISBN4-404-03413-X.
50 year history of the Japan Steel Works (first volume and second volume), Japan Steel Works, 1968.