Skip to main content

Researchers in Hawaii find lost Japanese WWII mega-sub

By Michael Pearson, CNN
updated 7:29 PM EST, Tue December 3, 2013
STORY HIGHLIGHTS
  • Researchers find the remains of an advanced submarine sunk by the U.S. Navy in 1946
  • The I-400 was essentially an underwater aircraft carrier
  • The Soviet Union wanted to inspect the sub's advanced technology
  • The sub represented a big shift in submarine tactics, a researcher says

(CNN) -- Researchers in Hawaii have found a mammoth World War II-era Japanese submarine scuttled by the U.S. Navy in 1946 to keep its advanced technology out of the hands of the Soviet Union.

The Hawaii Undersea Research Laboratory at the University of Hawaii discovered the I-400 in 2,300 feet of water off the southwest coast of Oahu, according the school.

"Finding it where we did was totally unexpected," lab operations director and chief submarine pilot Terry Kerby said in a university statement. "All our research pointed to it being further out to sea."

Piece of Civil War ironclad brought to surface in Savannah

At nearly 400 feet long, the I-400 and its two sister ships were the largest submarines ever built before the nuclear age.

Initially conceived as a weapon to target the U.S. mainland and capable of reaching any point on the globe without refueling, the subs were effectively underwater aircraft carriers outfitted with three folding-wing seaplanes capable of carrying an 1,800-pound bomb.

The ships were never used to attack the mainland United States and saw only limited service before Japan surrendered in 1945.

But their novel design represented a tactical shift in thinking about the use of submarines, which until then had been strictly seen as anti-ship weapons, James Delgado, director of the Maritime Heritage Program of the National Oceanic and Atmospheric Administration, said in the university statement.

Shipwreck hunters stumble across mysterious find

"Following World War II, submarine experimentation and design changes would continue in this direction, eventually leading to ballistic missile launching capabilities for U.S. submarines at the advent of the nuclear era," Delgado told the university.

The submarine was found in August, but the laboratory didn't notify the public until after informing the U.S. State Department and the Japanese government, the university said.

The I-400 was one of five Japanese submarines captured by the U.S. Navy at the end of World War II and sent to Hawaii for examination, the school said.

With tensions rising between the Soviet Union and the United States after the war, the Navy scuttled the ships to avoid their advanced technology falling into the hands of the Soviet navy in what would become one of the first intrigues of the Cold War.

The Hawaii Undersea Research Laboratory has so far found four of the ships.

Pearl Harbor survivor, 91, helps identify unknown dead

ADVERTISEMENT
Part of complete coverage on
updated 11:40 AM EDT, Sun July 20, 2014
Some contend that larger weapons have come into Ukraine from Russia.
updated 8:57 PM EDT, Sat July 19, 2014
Children and youth are often the victims of the violence in Gaza. CNN's Ben Wedeman reports.
updated 11:07 PM EDT, Mon July 21, 2014
A nun, an AIDS researcher, an athlete and a family traveling on summer vacation. These were some of the victims aboard MH17.
updated 2:21 AM EDT, Fri July 18, 2014
In an ambitious plan to upgrade urban India, Prime Minister Narendra Modi says he will build 100 "smart cities" across the country.
updated 7:27 AM EDT, Sun July 20, 2014
Inspirational, creepy or just weird? CNN meets the 51-year-old man who dresses like a schoolgirl.
shakespeare moon illustration
It's been 45 years since the first moon landing. And still the giant rock continues to intrigue.
updated 8:49 AM EDT, Fri July 18, 2014
Nelson Mandela
21 ICONS has captured intimate portraits of some of South Africa's most celebrated. Founder Adrian Steirn reveals the story behind the images.
updated 7:00 AM EDT, Thu July 17, 2014
A British nanotech company has created what it says is the world's darkest material.
updated 7:12 AM EDT, Fri July 18, 2014
Yoga, meditation and watching a snake eat a frog alive: these are some of the experiences to be had at this Himalayan yoga retreat.
updated 7:39 AM EDT, Thu July 17, 2014
Just a few weeks ago, a boy tied to a bus stop in Mumbai barely received a glance from passersby. Now, he has a home, thanks to a local NGO.
CNN joins the fight to end modern-day slavery by shining a spotlight on its horrors and highlighting success stories.
Browse through images from CNN teams around the world that you don't always see on news reports.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT