Japanese submarine Yu 3

After her delivery to the Japanese Army, Yu 3 initially remained in Japanese home waters while the Army constructed additional submarines of her class and established a training program for their crews.^[3] In May 1944, the Army created its first submarine combat unit (jissen butai), the Manila Underwater Transport Detachment (Manira Sensuiyuso Hakentai), consisting of Yu 3, her sister ships Yu 1 and Yu 2, and a mother ship.^[3] The detachment got underway from Japan on either 28^[3] or 30^[2] May 1944 (according to different sources) bound for Manila on Luzon in the Philippines.^[3] The vessels had a difficult voyage which included a number of mechanical breakdowns, but finally arrived at Manila on 18 July 1944.^[2][3] After their arrival, the three submarines underwent repairs and thorough overhauls.^[3]

On 20 October 1944, United States Army forces landed on Leyte, beginning both the Battle of Leyte and the broader Philippines campaign of 1944–1945.^[3] In November 1944, all three submarines got underway on their first supply run to Leyte.^[3] Yu 2 never arrived,^[3] but Yu 1 and Yu 3 reached Ormoc on Leyte's west coast on 27 November 1944 and discharged a combined 600 bags of white rice, 50 boxes of field rations, and 300 boxes of radio batteries.^[3]

In December 1944, Yu 1 and Yu 3 were sent to San Fernando on the northwest coast of Luzon.^[3] On 5 January 1945, while Yu 3 was transporting a cargo which consisted mostly of large bags of rice and bundles of welding rods for the Luzon garrison, U.S. aircraft attacked her in Lingayen Gulf, and she ran aground.^[2][3][4] Her crew scuttled her just off Damortis and abandoned her.^[2][3][4]

U.S. Army forces landed on the coast of Luzon in Lingayen Gulf on 9 January 1945, and shortly afterward U.S. forces found Yu 3 lying awash in shallow water just off Damortis.^[4] After United States Seventh Fleet personnel of the Seventh Fleet Intelligence Center inspected the wreck, the United States Navy decided to salvage Yu 3.^[4] The U.S. Navy rescue and salvage ship USS Grasp (ARS-24) refloated her on 18 January 1945,^[4][5] and she was towed across Lingayen Gulf to Sual.^[4] U.S. personnel examined her there, finding her cargo still aboard and no sign of any battle damage.^[4] Yu 3 subsequently was loaded aboard the dock landing ship USS Rushmore (LSD-14),^[4][5] which transported her to the United States in May 1945.^[5] By no later than early June 1945 Yu 3 was at Mare Island Navy Yard in Vallejo, California.^[5]

An article in the 8 June 1945 issue of the Mare Island Navy Yard's newspaper, The Grapevine, described Yu 3 as a 137-foot (42 m), 280-ton Japanese "cargo-carrying submarine" of crude construction powered by two six-cylinder diesel engines.^[5] The article said that she had no interior bulkheads and that her periscope operated by counterweights,^[5] and so could be raised only 3 feet (0.9 m). An article in the 22 June 1945 issue of The Grapevine identified her as Yu 3 and reported that the navy yard was offering tours of her and selling parts from her to raise money for war bonds.^[5] She subsequently probably was either scrapped or scuttled, sometime after early July 1945.^[3][5]

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• 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. ISBN 0-85177-396-6.
• Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. London, England: Conway Maritime Press. ISBN 0-85177-146-7.
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• The Maru Special, Japanese Naval Vessels No.43 Japanese Submarines III, Ushio Shobō, Tokyo Japan, 1980.
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• 50 year history of the Japan Steel Works (first volume and second volume), Japan Steel Works, 1968.