Japanese WWII megasubmarine found

The I-400 class (Photo: Wikimedia)

Probably because of the distractions of the holidays, I completely missed the December 2 report that a lost WWII Japanese megasubmarine had been found. As a kid I never missed a submarine movie or episode of TV’s “The Silent Service,” and I’ve been fascinated by submarines ever since.

The lost submarine was of the Sen Toku I-400 class, one of three giant subs the Japanese built that could carry and launch seaplanes armed with bombs. Their intended purpose was to attack and shut down the Panama Canal, one of America’s primary routes to the Pacific theater. At 400 feet, they were the largest submarines built prior to the nuclear submarines of the 1960s, with a range sufficient to reach any target on earth and return.

The subs were captured at the end of the war, before they could be used against the canal. After transporting them to Honolulu for examination, the Americans scuttled them in 2,300-foot-deep water off the island of Oahu. That action might be considered the first incident of the Cold War because the Soviets were demanding the right to examine them and US officials wanted to deny them access to the technology. The Soviets were told that the subs had been used as targets and sunk during a US naval exercise.

Much more on the I-400 class on Wikipedia and Google.

The I-400 class submarine (Art: rense.com)

6 thoughts on “Japanese WWII megasubmarine found

  1. Thanks for posting this, PT. Despite being a submariner myself, I wasn’t aware of this specific history. There is a thorough and professional Wikipedia page on this remarkable submarine design, including details on the Japanese Navy’s plans to use it.

    The I-400 design was clever, but it was evolutionary rather than completely novel If you read the Wiki page you will see that it had numerous flaws, all of which they were working on. Many of its concepts were incorporated in U.S. post-war designs, particularly in missile-carrying boats like the Regulus designs.

    The account reveals what a serious foe Nippon was in ferocity, daring, ingenuity and determination. If anyone reading this still doubts that Harry Truman made the wrong decision about the bomb, this ought to change their minds.

    1. Yes, I noted the Wikipedia article at the end of the post. I spent a lot of time browsing the various stories and looking at pictures. Fascinating. I’m puzzled that even though I was a war baby steeped in WWII stories during my childhood, I never heard of the I-400. It would have made one helluva movie. Still would, for that matter.

      1. Oops, yes I see your link now. It reads like some kind of Clancy novel. Also good fodder for Hollywood would be the clandestine snooping on the USSR’s undersea communications cables by USS Halibut during the Cold War.

        I think we know so little about these things is over-classification. Ridiculous that WW II stuff should still be under wraps decades later!

        1. I moved the link up so it would be more noticeable. I was pleasantly surprised to find such a detailed account on Wikipedia. I expected little more than a brief mention.

          I thought about Tom when I saw the story. I’ll bet he knew all about these subs. I didn’t read all his books, but as I recall one of them did involve snooping on underseas cables.

  2. Very informative. If you haven’t and get the chance, visit Groton, CT, for a great museum showing U.S. submarine history. While there, we saw “one of ours” come in from 60 days on patrol. Seeing a nuclear sub come home with everyone on the observation deck cheering was something I never will forget.

    1. I’m envious. What an experience that must have been! I lived in CT for about a year, back in 1970, but never got to Groton. I did, however, one summer in high school (1960, I think), get to tour a WWII submarine in San Diego harbor. Talk about claustrophobia! I learned my respect for submariners that day. Today’s boomers are limos by comparison.

... and that's my two cents