During World War II, the Japanese rushed to develop a fearsome secret weapon that could have turned the tide of the war - a fleet of giant Sen-Toku class submarine aircraft carriers, capable of launching bombing raids and the disappearing beneath the water, where they would be undetectable because of their rubberized sonar-blocking hulls.
Fortunately, the war ended before the Japanese could build more than a few of the giant subs. Seven decades later, pretty much all that remains of their plan is the wreck of the I-400, the first Sen Toku sub, which was seized by the U.S. Navy after the Japanese surrender in 1945 and then scuttled the following year, to avoid having to share its technology with the Soviet Union..
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Last week, researchers from the Hawaii Undersea Research Laboratory (HURL), who rediscovered the long-forgotten location of the scuttled sub in 2013, used submersible craft to descend to the site of the wreck, which lies 2,300 feet below the surface near the southwest coastline of the Hawaiian island of Oahu. They returned with a prized historical artifact– the ship's bronze bell.
In a press release, underwater explorer Terry Kerby, who led the expedition, called it "an exciting day." After the bell is put though a special preservation process, which should take a year, it will be put on display at the USS Bowfin Submarine Museum The archaeological find in the wake of a popular online TV series, an adaptation of Philip K. Dick's novel "The Man in the High Castle," which depicts an alternate history in which the Japanese and their German allies defeated the Allies and now jointly dominate the United States.
That nightmare might have had a chance at becoming reality, had the Japanese succeeded in their original plan to build 18 of the giant subs. At 400 feet in length and 5,223 tons of displacement, the Sen Toku were the biggest subs of the pre-nuclear era. Each craft was designed to store so much diesel fuel that it could sail one-and-a-half times around the world without stopping. They featured an unusual double-hulled design that supported a flight deck.
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As Stars and Stripes reported when the I-400 wreck was rediscovered in 2013, the Japanese only managed to launch two of the subs by mid-1945. Japanese military leaders contemplated using the I-400 and its sister sub, the I-401, to attack the Panama Canal, and near the war's end dispatched them to launch an attack on U.S. forces massing for the expected invasion of Japan. But before that could happen, the Japanese surrendered in August 1945, and the I-400 and the I-401 both were seized by the U.S. Navy.
To avoid complying with a treaty that required the United States to share captured technology with its then-ally the Soviet Union, the U.S. Navy secretly sailed the subs across the Pacific to Hawaii. After they were studied by engineers at Pearl Harbor, the Navy took the subs out to sea and scuttled both at undisclosed locations, and then claimed to the Russians that it had no knowledge of what had happened to them.
The wreck of the 401 was the first to be discovered, back in 2005.
Here's a video of the visit to the sub.