Ref.: HBOS-87017
IJN I-400 Submarine Sen Toku submarines were designed as submarine aircraft carriers, therefore, its dimensions were much larger than any existing submarine until then. They were able to transport on a cylindrical hangar three Aichi M6A seaplanes Seiran attack, specially designed to be folded and removed easily and vice versa, with regular flight range but with excellent maneuverability. Top speed on the surface was nearly 19 knots (6-7 immersion), operating at a maximum depth of 100 meters. They had a catapult on the bow for launching seaplanes bombers, and artillery was heavily over their predecessors in regard to anti-aircraft guns. The bridge was offset from the center line and was much higher than their peers.