Only days before the 72nd anniversary of the Pearl Harbor attack, the secret weapon of the Japanese admiral who planned the "Day of Infamy" has been found and positively identified at 2,300 feet in waters off Oahu. Research teams organized by the University of Hawaii at Manoa made the formal announcement Tuesday that the wreck on the Pacific bottom was the I-400, a submarine aircraft carrier that was the brainchild of Isoroku Yamamoto, the Japanese Marshal Admiral and commander-in chief of the Combined Fleet during World War II.
Yamamoto was the architect of the carrier attack that killed 2,300 and devastated the U.S. Pacific fleet at Pearl Harbor on Dec. 7, 1941.
The Sen Toku I-400-class (伊四百型潜水艦 I-yonhyaku-gata Sensuikan) Imperial Japanese Navy submarines were the largest submarines of World War II and remained the largest ever built until the construction of nuclear ballistic missile submarines in the 1960s. They were submarine aircraft carriers able to carry three Aichi M6A Seiran aircraft underwater to their destinations. They were designed to surface, launch their planes, then quickly dive again before they were discovered. They also carried torpedoes for close-range combat.
The I-400-class was designed with the range to travel anywhere in the world and return. A fleet of 18 boats was planned in 1942, and work started on the first in January 1943 at the Kure, Hiroshima arsenal. Within a year the plan was scaled back to five, of which only three (I-400 at Kure, and I-401 and I-402 at Sasebo) were completed.
