While Japan built many submarines that were larger than those of other Navies, the three Sen Toku boats were far larger than anything ever seen before. Some 60% larger than the largest contemporary American submarine, USS Argonaut, they had more than twice her range. The most unusual feature was that they each carried three floatplane bombers (and parts for a fourth), a feat never achieved by any other class of submarine. These aircraft folded to fit into the 115-foot cylindrical hangar, which was slightly offset to starboard and opened forward to access the catapult. The huge double hull was formed of parallel cylindrical hulls so that it had a peculiar lazy-eight cross section, and may have inspired the Soviet Typhoon-class built some 40 years later. Although aircraft must be considered their primary armament, they also carried a formidable torpedo battery and the usual 14cm deck gun. Anti-aircraft armament included ten 25mm cannons in three triple mounts and one single. Each of these boats had radar and a snorkel. The aircraft were the Aichi M6A1 Seiran, also carried by the Type AM submarines. Each of these monoplanes could carry one aerial torpedo or a bomb weighing up to 800kg. Powered by the 1,400hp Atsuta 32 engine (similar to Germany's DB601) they had a top speed of 295mph and were credited with a range of 642 nautical miles. The Sen Toku submarines carried four aerial torpedoes, three 800kg bombs, and twelve 250kg bombs to arm these aircraft. These aircraft had their assembly points coated with fluorescent paint to ease assembly in the dark, so four trained men could prepare an aircraft for launch in seven minutes. All three aircraft could be prepared, armed, and launched in 45 minutes. Mahogany Wood. Scale: 1/192. Length 25 inches.