Nisshin was a seaplane tender (CVS) of the Imperial Japanese Navy during World War II.She was built at Kure Naval Arsenal from 1938 to 1942 and was equipped with 2 aircraft catapults and facilities for launching, lifting and storing up to 25 floatplanes. Then in 1942 modifications were made for the ship to also carry Type 'A' midget submarines as well as carry and lay 700 naval mines in lieu of half of her aircraft complement.BackgroundDuring the 1930s, the Imperial Japanese Navy made increasing use of naval aviation as scouts for its cruiser and destroyer squadrons. Due to restrictions imposed by the Washington Naval Treaty and London Naval Treaty, the number of aircraft carriers was strictly regulated; however, there was no limitation as to seaplane tenders. Nisshin was a follow-on to the purpose-built seaplane tender design begun with the Chitose-class and was ordered by the Imperial Japanese Navy under the 3rd Naval Armaments Supplement Programme of 1937.DesignNisshin was designed with two aircraft catapults for launching seaplanes, and cranes for recovering landed aircraft on her aft deck, which included a hangar. She also had two elevators to transport aircraft from the ship's interior, and a second hangar for aircraft storage below the deck, along with 900 tonnes of aviation fuel. As designed, Nisshin carried a complement of 25 Kawanishi E7K Type 94 "Alf" and Nakajima E8N Type 95 "Dave" and Mitsubishi F1M floatplanes, of which 20 were operational, and five were stored partly disassembled as a reserve below deck. In addition, Nisshin could carry up to 700 naval mines