World War II Japanese mega-submarine found off coast of Hawaii

Just under 70 years after being intentionally sunk by U.S. forces in 1946, the University of Hawaii Manoa says a Japanese aircraft-carrying mega-submarine was discovered off the Hawaiian island of Oahu in August.

The I-400 “Sen-Toku” class submarine, which at 400 feet measured the largest submarine built until the advent of nuclear subs in the 1960s, had been designed to hold up to three float-planes bombers that could be catapulted within minutes of surfacing. The found sub, along with others, had been captured by the U.S. Navy and sunk off the coast of Hawaii to avoid giving access to the ships to the Soviet Union as part of a war treaty.

The University of Hawaii Manoa, which helped fund the dive alongside NOAA, published the find after the discovery was reviewed with the U.S. and Japanese governments.

“Our ability to interpret these unique weapons of the past and jointly understand our shared history is a mark of our progress from animosity to reconciliation,” Van Tilburg, a maritime heritage coordinator for NOAA, said in the press release. ” That is the most important lesson that the site of the I-400 can provide today.”