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Japanese Submarine I-400 Class Aircraft Carriers of WW2

Did you know that the Japanese developed a submarine aircraft carrier during World War II? That's right you are reading that correctly. If you did, congratulations you are a military history aficionado. If not, don't despair let us introduce you to I-400 class submarine.

The idea was to provide a ship with the potential to raid the American coastline during the war. With a fleet of 18 planned they were the brainchild of none another that Admiral Yamamoto. The ebb and flow of war meant the fleet was never completed.

Each of these impressive machines was powered by four 1,680 kW engines. They even had enough fuel to travel around the world one and a half times. They measured 120 meters in length and displaced around 5,900 tons, which was more than double that of their American counterparts. Their cross section was a unique figure of eight configuration, owing to the top aircraft hangar. This provided the necessary strength and stability to afford the ship of handling the additional weight of the hangar and not make them top heavy. The aircraft hangar was just below the conning tower and fixed along the ship's centerline.

This aircraft hangar was, obviously, water tight and cylindrical in form. Its outer access door was opened hydraulically internally or manually from the outside. It had a 51 mm thick rubber gasket.

Not only did the ship have aerial strike capabilities but was also equipped with some of the largest guns ever seen on a submarine. She was equipped with three waterproofed Type 96 triple mount 25mm anti-aircraft defense guns and a single Type 11 140mm deck gun aft of the hangar! Wow.

The vessel, being a submarine, was also equipped with 8 torpedo tubes mounted at the bow with no aft tubes. It couldn't be too awesome after al

Fighters were launched from a 26-meter forward deck mounted compressed air catapult at the bow of the ship. The fighters were recovered using a storable collapsible crane. Underneath the track, four high-pressure air flasks were connected in parallel to provide sufficient "thrust" to launch the fighters to takeoff speed.

During fighter deployment, rapid launch of fighters was a necessity. As older WW2 fighters usually required some time to warm up, specially designed oil pre-heaters were employed to get the engines up to operational temperature as quickly as possible. This was also essential as you couldn't have engines ticking over when submerged, you might just kill the crew!