Video/Photos: Divers Discover Sunken Submarine's Airplane Hangar

I-400's large aircraft hangar found off coast of O'ahu.

Sunken I-400 Submarine Aircraft Hangar

Sunken I-400 Submarine Aircraft Hangar

Photo: NOAA

Divers searching the wreckage area of a sunken I-400 World War II Japanese submarine off the coast of O'ahu recently came upon an interesting find: the massive submarine's missing aircraft hangar.

The hangar and other key features of the mega-submarine were separated from the main wreckage, discovered by University of Hawaii and U.S. National Oceanic and Atmospheric Administration divers in 2013, when U.S. forces intentionally sank the sub at the end of the war to prevent the technology from getting into the hands of the Soviet Union.

"We made a lucky guess where to start when we approached the main hull of the I-400 from the northwest. Our guess started to pay off when the giant hangar door came into view, followed by the conning tower and hangar," Terry Kerby, Director of Submersible Operations at the Hawai‘i Undersea Research Laboratory, said in a university news article. "Many items were amazingly intact for something that had ripped out of the hull of a sinking 400-foot-long submarine."

The I-400 submarines — a total of three were built — that entered service toward the end of World War II were the biggest subs ever built at the time. The I-400's hangar was large enough to house three Aichi M6A Seiran attack seaplanes each capable of carrying an 1,800-plus-pound bomb for surprise coastal attacks.

Check out the photos and video of the find here.

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