The Japanese submarine I-58 was the IJN submersible vessel that torpedoed and sank the American cruiser USS Indianapolis on July 30, 1945, at the end of World War II. She belonged to the B3 Type class of cruiser submarines, the first of which, the I-54, had been launched in May 1943. The I-58 was launched on October 9, 1943, and she was commissioned for service with the Imperial Japanese Navy on September 7, 1944. She was armed with four Kaiten and fourteen Type-95 torpedoes that were fired through 533-mm tubes. The Type-95 was a conventional torpedo fitted with a 405-kg warhead, while the Kaiten was a manned, kamikaze torpedo, which was used by every Japanese sub at the end of this armed conflict.
The I-58 submarine had been laid down on December 26, 1942 at the Yokosuka Naval Arsenal, and launched on October 9, 1943. During the construction of the boat, her 14 cm/40 11th Year Type naval gun was removed to make room for the four Kaiten manned kamikaze torpedoes. The submarine was finally completed on September 7, 1944; Lieutenant Mochitsura Hashimoto was appointed commander of this Japanese boat. After intensive training, the I-58 was assigned to the 15th Submarine Division on December 4, 1944. A few days later she was assigned to the Kongo ("Diamond") group, with I-36, I-47, I-48, I-53 and I-56, to attack five US fleet anchorages with Kaiten torpedoes.
After the American invasion of Iwo Jima in February 1945, I-58 and I-36 joined the Shimbu group which was formed to counterattack American forces, but they did not succeed. On July 30, 1945, I-58 sank USS Indianapolis (CA-35) with three Type 95 torpedoes, with about 40% of the surviving crew being eaten by sharks. Because the cruiser was not zig-zagging, her captain was held accountable for the ship's loss. With the help of I-58's skipper, his name was finally cleared in 2000. Thus, she was a prime player in one of the most controversial episodes in US naval history. I-58 survived the war only to be scuttled in April 1946.
Specifications
Type: B3 Type cruiser submarine
Displacement: 2,607 tons (surfaced); 2,365 tons (submerged)
Length: 108.7 m
Beam: 9.3 m
Draft: 5.2 m
Propulsion System: two 4,700-sHP diesel engines, driving two shafts; two 1,200-HP electric motors.
Maximum Speed: 17.75 knots (surfaced); 6.5 knots (submerged)
Range: 21,000 nautical miles
Crew: 94
Armament: six 533-mm launching tubes, with 14 Type-95 torpedoes, and four Kaitens.
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| Above, the IJN submarine I-58 in late 1943. |
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| Lt. M. Hashimoto, the commander of the I-58. |
