Japanese submarine I-64

Upon commissioning, I-64 was assigned to the Sasebo Naval District.[2]

As the Imperial Japanese Navy began to deploy in preparation for the impending conflict in the Pacific, I-64 — which together with I-62 made up Submarine Division 29, a part of Submarine Squadron 5 — departed Sasebo, Japan, on 26 November 1941 bound for Palau along with the rest of Submarine Squadron 5, namely I-62, the submarines of Submarine Division 30, and the squadron's flagship, the light cruiser Yura.[2] While en route, the entire squadron was diverted to Samah on Hainan Island in China.[2]

On 5 December 1941, I-64 departed Samah to begin what would become her first war patrol.[2] When the Japanese invasion of Malaya began on 8 December 1941 — the first day of the war in East Asia — I-64 was in the South China Sea off Trengganu, British Malaya, operating as the easternmost submarine on a patrol line with the submarines I-57, I-58, I-62, and I-66.[2] Reassigned to Patrol Unit "B" on 26 December 1941,[2] she concluded her patrol by arriving at Cam Ranh Bay in Japanese-occupied French Indochina on 27 December 1942.[2]

As a unit of Patrol Group "B," I-64 was among submarines tasked with attacking Allied shipping in the Indian Ocean west of the 106th meridian east, operating from a new base at newly captured Penang in Japanese-occupied British Malaya.[2] Accordingly, on 7 January 1942 I-64 departed Cam Ranh Bay to begin her second war patrol.[2] At 16:30 local time on 22 January 1942 while in the Indian Ocean 550 nautical miles (1,020 km; 630 mi) west of Sibolga, Sumatra, she fired two torpedoes at the Dutch 4,482-gross register ton Koninklijke Paketvaart-Maatschappij merchant ship Van Overstraten, which was on a voyage from Bombay, India, to Oosthaven, Sumatra.[2] After one torpedo passed ahead of Van Overstraten and one passed under her keel, leaving her undamaged, I-64 surfaced and opened fire on Van Overstraten with her deck gun.[2] She scored a number of hits, slowing Van Overstraten and killing four members of her crew.[2] Van Overstraten stopped and her surviving crew abandoned ship in her lifeboats.[2] After waiting for the boats to pull away to a safe distance, I-64 hit Van Overstraten with a torpedo shortly before sunset, and Van Overstraten sank by the bow at 01°40′N 090°13′E.[2] There were 113 survivors.[2]

At 05:47 GMT on 28 January 1942, I-64 surfaced in the Palk Strait north of Ceylon and opened fire with her deck gun on the 391-gross register ton British Inland Water Transport paddle steamer Idar, which was steaming from Madras to Cochin, India.[2] After a shell hit Idar, her crew abandoned ship at 05:58 GMT at 10°12′N 080°13′E. I-64 sent a boarding party to Idar to set her on fire, but she survived and later drifted ashore.[2] On 29 January 1942, I-64 torpedoed the American 5,049-gross register ton passenger-cargo steamer Florence Luckenbach — bound from Madras to New York City via Cape Town, South Africa, carrying 3,500 tons of general cargo and 3,400 tons of manganese ore — in the Indian Ocean 15 nautical miles (28 km; 17 mi) southeast of Madras at 10:05.[2] The torpedo hit blew a large hole in Florence Luckenbach′s port side at her No. 1 hold.[2] Ten minutes later, Florence Luckenbach′s entire crew of 38 abandoned ship in her single surviving lifeboat.[2] I-64 waited until the lifeboat and reached a safe distance from Florence Luckenbach and then hit her with a second torpedo, and Florence Luckenbach sank by the bow at 12°55′N 080°33′E.[2]

At 22:33 on 30 January 1942, I-64 torpedoed the British-Indian 2,498-gross register ton merchant steamer Jalatarang — on a voyage from Cochin, India, to Rangoon, Burma, carrying 100 tons of general cargo — in the Bay of Bengal south of Madras, crippling her.[2] I-64 then surfaced and finished off Jalatarang with gunfire, sinking her 12°59′N 081°00′E.[2] Thirty-eight members of Jalatarang′s crew perished, and 11 eventually were rescued.[2] I-64 was in the Bay of Bengal 50 nautical miles (93 km; 58 mi) south of Madras on 31 January 1942 when she torpedoed the British-Indian 4,215-gross register ton cargo steamer Jalapalaka — steaming in ballast from Bombay to Rangoon — at 13:00 GMT.[2] She then surfaced and sank Jalapalaka with gunfire at 13°00′N 081°08′E.[2] Thirteen members of Jalapalaka′s crew died, and 54 later were rescued.[2] I-64 finished her patrol with her arrival at Penang on 5 February 1942.[2]

On 6 March 1942, I-64 set out from Penang to begin her third war patrol, again targeting Allied shipping in the Indian Ocean.[2] While she was at sea, Submarine Division 29 was disbanded on 10 March 1942 and she was reassigned to Submarine Division 30 in Submarine Squadron 5.[2] She was in the Indian Ocean off India′s Coromandel Coast 150 nautical miles (280 km; 170 mi) northeast of Madras when she surfaced at around 12:10 GMT and opened fire with her deck gun on the Norwegian 1,513-gross register ton armed cargo steamer Mabella, which was on a voyage in ballast from Colombo, Ceylon, to Calcutta, India.[2] After she scored 12 hits on Mabella, killing six members of her crew, Mabella′s surviving crew abandoned ship in two lifeboats and a raft.[2] After waiting for the lifeboats and raft to reach a safe distance from Mabella, I-64 opened fire on her again with her deck gun, then hit her with a torpedo, sinking her at 14°00′N 081°47′E.[2] On 27 March, I-64 returned to Penang.[2]

On 2 April 1942, I-64 departed Penang bound for Sasebo,[2] where she arrived on 12 April 1942.[2] On 16 May 1942 she departed Sasebo bound for Kwajalein, deploying to support Operation MI,[2] the invasion of Midway Atoll planned for early June 1942.

On 17 May 1942, the United States Navy submarine USS Triton (SS-201) sighted I-64 on the surface in the Pacific Ocean 250 nautical miles (460 km; 290 mi) south-southeast of Cape Ashizuri, Shikoku, Japan at 18:03.[2] At 18:17 Triton fired the last remaining Mark 14 torpedo in her forward torpedo room at I-64 at a range of 6,200 yards (5,670 m).[2] The torpedo struck I-64, the explosion blowing parts of her 100 feet (30 m) into the air.[2] I-64 sank by the stern in two minutes at 29°25′N 134°09′E.[2] Triton′s crew heard a series of 42 smaller explosions beginning at 18:27.[2] At 18:45, Triton′s commanding officer sighted an estimated 30 survivors clinging to wreckage in the water.[2] Ultimately, none of them were rescued.

Unaware of I-64′s loss, the Imperial Japanese Navy renumbered her I-164 on 20 May 1942.[2] On 25 May 1942, it declared her presumed missing in the Pacific Ocean south of Shikoku with the loss of all 81 hands.[2] She was stricken from the Navy list on 10 July 1942.[2]