Scientists have accidentally discovered a wrecked super-submarine off the coast of Hawaii that had been missing for more than 65 years.
One of the jewels of the Japanese fleet in the Second World War, it was a technological marvel, and among the largest pre-nuclear submarines ever built.
Yet despite measuring 400 feet (122 metres) long, the “Sen-Toku” class I-400 had remained a mystery to military historians since it was sunk by US forces protecting the Panama Canal.
Divers stumbled across the mega-sub some 2,300 feet beneath the surface of the Pacific Ocean. It was among the first to be able to carry aircraft and could travel one-and-a-half times around the world without needing to refuel.
Jim Delgado, a researcher who was aboard the Pisces V deep-diving submersible which travelled to the wreckage, told the Reuters news agency: “We came upon this as we were looking for other targets… It is like watching a shark at rest.”
The US Navy captured five Japanese submarines at the end of the Second World War and brought them to be inspected at Pearl Harbor.
American forces lost the I-400 whose discovery was announced this week after they deliberately scuttled it in 1946 to avoid the technology falling into Soviet hands.
“It was torpedoed, partially collapsed and had sunk at a steep angle,” said Delgado, an archaeologist with the National Oceanic and Atmospheric Administration (NOAA), which helped to fund the dive.
Only one submarine in the giant I-400 class remains missing. Researchers said the latest discovery was announced only after the NOAA had reviewed its findings with both the US State Department and Japanese government officials.