Undersea explorers discover WWII-era submarine off Hawaiian coast

ABOVE: A World War II Japanese submarine last seen before it was sunk in 1946, was discovered on August 1 off the island of Oahu by a submersible operated by the Hawaii Undersea Research Laboratory (HURL). Footage released by HURL on December 2 shows the first glimpse of the 400 foot long submarine in 67 years.

Thought lost for over 60 years, naval relic hunters have discovered one of three Japanese mega-submarines from the WWII era.

According to a press release issued by the University of Hawaii System, the Hawaii Undersea Research Laboratory (HURL) came across the Imperial Japanese navy mega-submarine by chance.

“The I-400 has been on our ‘to-find’ list for some time. It was the first of its kind of only three built, so it is a unique and very historic submarine,” Terry Kerby, HURL’s operations director and chief submarine pilot, said in the release. “Finding it where we did was totally unexpected. All our research pointed to it being further out to sea.”

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Kerby’s team came across the downed submarine in August while scouring the deep sea floor for anomalies through sonar imaging.

It was able to confirm the ship’s identity based on numerous physical features such as torpedo tubes and deck crane. It was the first of just three submarines like it, says Kerby.

A sea-faring behemoth

On paper, The I-400 shares the same feature list as Superman. The “Sen-Toku” class submersible was able to travel around the world one-and-a-half times before needing to refuel. It could hold up to three float-plane bombers equipped with an 816-kilo payload that it could literally catapult into the air.

“The innovation of air strike capability from long-range submarines represented a tactical change in submarine doctrine,” said archaeologist Dr. James Delgado in the release. Delgado joined Kerby’s team on the dive.

Despite the obvious research and development that went into designing the I-400 and its fellow Sen-Toku class ships, its use by the Japanese was cut short by the end of WWII, and was among a group of five submarines captured by the U.S. Navy.

Relinquished to the depths

The I-400 survived the carnage World War II, only to be one of the first casualties of a very different kind of conflict.
At the end of the war, the Soviet Union insisted it be granted access to the captured ships, which it was entitled to under the treaty that ended the war.
But rather than hand over advanced nautical technology to what was then an emerging threat, the U.S. Navy shot three torpedoes into I-400’s hull, later claiming it did not know exactly where it was.

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And it was there off the coast of Oahu that a warship the size of three football fields lay dormant, 2,300 feet under the ocean.
Until now.

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