Submarines of the Imperial Japanese Navy
Imperial Japanese Navy (IJN) submarines formed by far the most varied fleet of submarines of World War II, including manned torpedoes ("Kaiten"), midget submarines ("Kō-hyōteki", ), medium-range submarines, purpose-built supply submarines (many used by the Imperial Japanese Army, see Type 3), fleet submarines (many of which carried an aircraft), submarines with the highest submerged speeds of the conflict ("Sentaka" ), and submarines able to carry multiple bombers (World War II's largest submarine, the Sentoku ). They were also equipped with the most advanced torpedo of the conflict, the oxygen-fuelled Type 95 (which are sometimes confused with the famed Type 93 Long Lance torpedo).
Japanese submarine I-25
Two submarines were sighted on 11 October 1942 about off the coast of Washington as "I-25" was returning to Japan. "I-25" fired its last torpedo at the lead submarine, which sank in 20 seconds with the loss of all hands. "I-25" reported sinking a U.S. submarine, but the submarine was actually Soviet "L-16" which was sailing with "L-15" en route from Vladivostok to the Panama Canal via Unalaska, Alaska and San Francisco. United States Navy Chief Photographer's Mate Sergi Andreevich Mihailoff of Arcadia, California, was aboard "L-16" as a liaison officer and interpreter, and was killed with the remainder of the submarine crew. The United States Navy Western Sea Frontier denied loss of any submarine and withheld information about the Soviet loss because, at the time, the Soviet Union was officially neutral in the war between Japan and the United States.