All five C1 boats carried midget submarines for the Pearl Harbor attack. Three later deployed to the Indian Ocean, where their midgets damaged a British battleship and sank a tanker, while the parent submarines subsequently sank fourteen freighters as commerce raiders. Further midget attacks off Guadalcanal damaged only one U.S. Navy transport. I-22 and I-24 carried midgets for the Sydney attack, whose limited result was the sinking of an old accommodation ferry. The boats also undertook supply missions as the war continued. I-18, I-16 and I-20 were lost to U.S. destroyers, and I-22 went missing in the eastern Solomons. I-24, a submarine of about 2,500 tons, was rammed and sunk off the Aleutians by a 675-ton submarine chaser.
Notable Point · 2:45:42-2:46:55
C1 operations from Pearl Harbor to supply missions and losses
The C1 boats combined distant midget attacks and commerce raiding with supply missions before all five were lost or went missing.