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.
Yokosuka E6Y
The Imperial Japanese Navy was a pioneer in naval aviation, starting as early as 1912 with the purchase of two floatplanes from Britain and one from the United States. By December 1922, Japan had completed "Hōshō", which vies with as the first ship purpose-designed for aircraft operations. Alongside that development, the Navy also looked at aircraft as a way to extend the operational reach of their large submarine force. Aware of the challenge of operations in the large expanse of the Pacific Ocean, the Navy was particularly looking at ways to improve their reconnaissance capability and saw submarine-based aircraft as a complement to land--based patrol. They acquired a Caspar U.1 from the United States and a Parnall Peto from Britain, both early submarine-based reconnaissance aircraft. The two aircraft formed the basis for two prototype Japanese aircraft built for submarine-based reconnaissance, the 1-Go based on the former, while the latter heavily influenced the 2-Go.