Japanese submarine I-12

The submarine I-12 was a Japanese A2 type long-range fleet submarine. She was built at the Kawasaki's shipyard in Kobe.

Wartime service
The I-12 sailed from the Inland Sea on 4 October 1944 to disrupt American shipping between the west coast and the Hawaiian Islands.

The I-12 torpedoed and sank the Liberty ship John A. Johnson, on 30 October 1944. I-12, after ramming and sinking the lifeboats and rafts, then machine-gunned the 70 survivors in the water, killing 10. A Pan American Airways plane spotted the John A. Johnson's remaining men soon thereafter, and the USS Argus recovered them at 21:35 on 30 October. The Argus disembarked the men at San Francisco on 3 November.

Sinking
I-12 was sunk by the US minesweeper Ardent and the USCG cutter Rockford on 13 November 1944, 10 days after the sinking of the John A. Johnson, near Kauai in the Hawaiian Islands.

The Ardent and the frigate Rockford were escorting a six-ship convoy midway between Honolulu and the United States. At 12:32, Ardent's sonar picked up a submarine contact. Ardent attacked first at 12:41, firing a 24-charge "hedgehog" pattern, and again at 12:46 with a second "hedgehog" pattern. Rockford left her escort station to assist, and fired her first barrage of rockets from her "hedgehog" at 13:08; two explosions followed, before an underwater detonation rocked the ship. Ardent carried out two more attacks and the frigate dropped 13 depth charges to administer the coup de grace. The resulting explosions caused a loss of all contact with the I-12.

Wreckage recovered on the scene—deck planks, ground cork covered with diesel oil, a wooden slat from a vegetable crate with Japanese writing and advertisements on it, pieces of varnished mahogany inscribed in Japanese, and a piece of deck planking containing Japanese builders' inscriptions—indicated a definite "kill".