Harushio-class

The Harushio class is a series of diesel-electric submarines operated by the Japan Maritime Self-Defense Force (JMSDF). Developed as an evolution of the preceding Yūshio class, the design was produced to replace the Uzushio class. Mitsubishi Heavy Industries and Kawasaki Shipbuilding Corporation constructed the vessels between 1987 and 1997, with seven units completed.

The design utilizes a double hull system constructed from NS 110 steel. The hulls are treated with an anechoic coating to reduce the acoustic signature. Propulsion is provided by a diesel-electric system driving a single shaft. Early units utilized Kawasaki diesel engines, while later vessels were equipped with Mitsubishi-MAN diesel engines and Toshiba electric motors. Sensor systems include hull-mounted and towed array sonars, I-band search radar, and electronic support measures suites. Armament consists of amidships torpedo tubes capable of launching torpedoes and Harpoon anti-ship missiles.

The final vessel of the class, Asashio, was modified with increased automation in its engineering control systems, which allowed for a reduced complement. Asashio later served as a test bed for air-independent propulsion (AIP) technology. To accommodate the installation of a Stirling AIP unit, the submarine underwent a hull extension.

The class was in commission from 1990 to 2017. During their service life, several units, including Hayashio, Fuyushio, and Asashio, were reclassified as training submarines. The Harushio class was retired and replaced by the Oyashio class.