quote:
In 1945, just after Japan surrendered to the United States to end the second world war, a Japanese I-400 class submarine– the likes of which Americans had never seen– surrendered to a Navy destroyer. The Americans were surprised at the submarine's enormous size, and subsequent inspections continued to astonish. It was about 60% larger than the largest US submarines, twice as fast as the fastest US subs, and had the fuel capacity to travel around the Earth one and a half times before refueling. Perhaps most impressively, it was also an aircraft carrier.
/unquote
Pure, unmitigated baloney.
Yes, it was big. 1800 tons or so larger than our 1930 Narhwhal class boats, Narwhal and Nautilus.
The French 1930 Surcouf carried float planes, and had a dual 8-inch gun turret. It displaced about 3800 Tons, and went 18 Kts on the surface, 10 Kts submerged. Range was 10000 miles or so. Design depth was 250 feet.
Our Balao (improved Gato, 132 built 1942-44) class boats went 20 knots on the surface, and a range of 12000 miles. They carried no seaplane. Design depth was 400 feet.
The I-400 did have a long, loong range of 37000 miles. Design depth was 330 feet. Two were built.
IMO, putting that quantity of resources into carrying three floatplanes was a huge waste, worthy only of desperate men losing a war.