"Japanese Monster Aircraft Carrier Submarines" Topic

"The Japanese Navy under the visionary Admiral Yamamoto (architect of the Pearl Harbor Assault in December 1941) developed a plan for a fleet of huge Subs that each carried 3 Hi-Tech attack/ bombers inside a tubular hangar, that was mounted on a double tubular fuselage. The novel design of the I-400 series (built in December 1944) gave stability with 2 hulls welded next to each other and made up for the largest Submarine ever built until the 1960's nuclear subs came out.

Overall length was almost 400 whopping feet (122 m) and an unrivaled armament of a huge 140 mm canon (never seen before on a sub) plus 4 power packs with 25 mm AA guns and special torpedo's inside. The Monster Subs were weighing 5,700 tons, carrying a crew of 200 and possessing a range of over 50,000 miles, with weapons and 3 aircraft designed to become the first Submarine fit for an offensive strike on the US mainland targets on West & East Coast!

The real surprise novel was on top of the double hull, a spectacular hangar with inside 3 Aichi-M6 Seiran aircraft that could each carry an 1850 lbs. bomb over 1,000 miles. From a long launch ramp on the front deck of the sub, a steam catapult was used to shoot the aircraft airborne and after landing on their floats, a foldable crane was used to hoist the aircraft back on board. Five of the Monster Subs were built, but only three were launched. One made a trip around the Horn of Africa to Germany and another one was converted as a sub-tanker. The I-400 series submarine had a number of advanced features like radar and the by Germans invented snorkel for extended underwater cruising on the Diesel engines, allowing the batteries to be charged. But most amazingly also stealth technology: energy absorbing skin with a rubberized coating that would help the submarine remain undetected by sonar equipment of the Allied Sub hunters…"

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Amicalement
Armand

While a 140mm gun may have been an unusual size for a sub's gun it wasn't the largest by any means. I think that honour goes to the British WW1 M class with 12inch (300mm) guns.

France built Surcouf with twin 8in & the US built 'cruiser' subs with 6in guns.

Thanks!.

Amicalement
Armand