Submarines of the Imperial Japanese Navy
The ("I-15"-class) submarines (, , , , , , , , , , , , , , , , , , , ) were the most numerous type of submarines of the Imperial Japanese Navy during World War II. In total 20 were made, starting with "I-15", the class ship. These were fast, very long ranged, and carried a single Yokosuka E14Y seaplane, located in a hangar in front of the conning tower, launched by a catapult.
Japanese submarine tender Komahashi
The Imperial Japanese Navy received its first submarines during the Russo-Japanese War, but these vessels were not operational until after the war ended. During the post-war period, submarine warfare was given a low priority for development, as the early submarines were regarded as unsafe, and useful only for short-range coastal point defense.