UK & World News

  • 4 December 2013, 13:56

Japanese WW2 'Mega-Sub' Found Off Hawaii

A World War Two Japanese "mega-submarine" lost when it was scuttled by US forces has been seen for the first time since 1946 after it was discovered off the coast of Hawaii.

The 400ft I-400 Sen-Toku class submarine - the largest submarine built until the introduction of nuclear-powered submarines in the 1960s - was found on August 1 off the island of Oahu.

A submersible operated by the Hawaii Undersea Research Laboratory (HURL) captured footage of the vessel in more than 2,300ft of water.

Veteran undersea explorer Terry Kerby said: "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.

"Finding it where we did was totally unexpected. All our research pointed to it being further out to sea.

"It was a thrill when the view of a giant submarine appeared out of the darkness."

The I-400 could carry up to three folding-wing Seiran float-plane bombers launched by catapults from the surface, before it dived under the water again to avoid detection.

Each aircraft could carry a 1,800lb bomb to attack the US mainland, but they were never used.

Only three of the submarines, which had a range of 37,500 miles, were ever completed.

At the end of World War Two the US Navy captured five Japanese submarines, including the I-400, and brought them to Pearl Harbour for inspection.

When the Soviet Union demanded access to the submarines in 1946 under the terms of treaties that ended the war, the US Navy sank the submarines off the coast of O'ahu and claimed to have no information of their precise location.

Using side-scan and multi-beam sonar data, the HURL has now successfully located four of the five lost submarines.

The I-400 was identified by its aircraft launch ramp, deck crane, torpedo tube configuration and stern running lights.