Underwater Aircraft Carriers: Imperial Japan’s Secret Weapon

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In August of 1945, as the world celebrates Imperial Japan’s surrender and the effective end of the second world war, the American’s make a puzzling discovery out in the Pacific. The US Navy has intercepted a Japanese submarine that’s unlike anything they’ve seen before. It’s by far the largest submarine ever constructed, at nearly twice the length of a typical German U-boat. But it’s what the submarine carries that truly baffles the Americans.

The Japanese I-400-Class submarine’s most unusual feature was that it carried three torpedo/dive bombers inside an internal hanger. In order to fit, these full size attack float planes had wings and tailplanes that could be folded. The submarines also featured a catapult launch system and a crane mechanism to recover the aircraft. The I-400 submarine was effectively the world’s first underwater aircraft carrier. It was also a formidable submarine in the conventional sense, heavily armed with torpedo tubes, an enormous deck gun and anti-aircraft cannons.

Conceived as a secret Japanese weapon at the start of the Pacific war, a fleet of I-400 submarines would be tasked with launching surprise attacks on New York, Washington, San Francisco, San Diego and Los Angeles. The attacks were intended to shake the will of the American people to keep fighting in the war. But as the war turned against Imperial Japan, shortages in war materials and shifting military priorities resulted in only 3 I-400 completing construction before Japan’s surrender. Fortunately, the I-400 was never allowed to demonstrate it’s true capacity.

Select footage courtesy the AP Archive:
AP Archive website: http://www.aparchive.com YouTube: https://www.youtube.com/c/aparchive and https://www.youtube.com/c/britishmovietone

Special thanks to Nick Arehart for helping clean up our audio:

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Music (reproduced under license):
Intro Song: “Tyberius” – https://www.pond5.com/royalty-free-music/item/73790133-tyberius-alternate-mix-orch
Song 2: “Warrior Epic Cinematic Adventure” – https://audiojungle.net/item/warrior-epic-cinematic-adventure/20660894
Song 3: “Red Sunrise” – hhttps://www.pond5.com/royalty-free-music/item/70955778-f-giovannangelo-red-sunrise-60-secs-version
Song 4: “Norway Lights” – https://audiojungle.net/item/norway-lights/21072417
Song 5: “Inquisitive Explorer Documentary” – https://www.pond5.com/royalty-free-music/item/99226577-inquisitive-explorer-documentary-60-sec-part-2
Song 6: “For Documentary” – https://audiojungle.net/item/for-documentary/25760942
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22 thoughts on “Underwater Aircraft Carriers: Imperial Japan’s Secret Weapon

  1. and they (japan) has made this into 45minute animated series in 80's .

  2. This kinda stuff is why I love learning history

  3. Robert Edgar Wells says:

    They need to stop this lie about an unknow attack as its common knowledge IBM Ford and others where involved in adding Germany and in the war process and as Japan Germany Italy Turkey where one in this war together they added and new what was going on edged on & financed by evil elite bankers, companies & Democrat Satanists who were and are still our real enemy today like Biden Harris Pelosi Clinton's Obama's Bush family.


  4. Raleigh Kellyc says:

    Yamamoto was deloutional

  5. Blank Name Slot says:

    Well it ain’t secret anymore

  6. Now my favorite ww2 sub, and not just because of Arppegio of Blue Steel.

  7. Lotry Camill says:

    The atomic bombs 💣 has to be dropped in Germany but thank God Russia 🇷🇺 and United Kingdom 🇬🇧 destroyed Germany 🇩🇪 military and there was no need to drop in Germany

  8. Lotry Camill says:

    Today japan 🇯🇵 are on the side of America but China 🇨🇳 are on the bad guys group

  9. Micah Lol88 says:

    America: we need to destroy this sub it’s to powerful, what if others built something like this.

    also America: nuke

  10. Jonki Pastramki says:

    The cynical quart simultaneously explode because faucet disappointingly cause mid a fresh craftsman. unsightly, unbecoming hand

  11. M1 LEGEND says:

    I admire Japanese on being intelligent in the art of war

  12. I know you said they would ditch the plane after their mission but most likely they would do any damage they could and end up flying it into a asset or military target.

  13. Teddy Nebel says:

    I bet the USA has some built after that.

  14. Aniket Shukla says:

    It's funny how the U.S. always tries to claim that 'it' is on the right side and all others in the wrong. History throughout tells us how in a majority of the wars the U.S. only participated for her and her capitalist's own gain.

  15. Preston Allen says:

    POV: you are here because of Pewdiepie’s video

  16. winiel juanitas says:

    this is like space battleship Yamato

  17. so we sank them to keep them from the Russians?

  18. damn these subs were savage!

    makes me want to play command & conquer lol

  19. Jack Wilson says:

    We’ve got submarines that can carry aircrafts
    We’ve got ships that can carry aircrafts
    Now we need aircrafts that can carry aircrafts

  20. Larry Small says:

    That was nothing new the U.S. was testing subs like that in the early 1920s but saw they had limited actually use plus French. England and others had similar subs but Japan's was the largest

  21. Randall Rodrigues says:

    That's fake as shit underwater aircraft carriers lmao .are thay underwater aircraft too .

  22. Trilochan velmurugan says:

    To be more general knowledge related August 15 1945 is the day that the British left the india

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