Kaichū type submarine

Class overview
Name	Kaichū type submarines
Builders	Kure Naval Arsenal; Sasebo Naval Arsenal; Yokosuka Naval Arsenal; Kawasaki Shipbuilding; Mitsui Engineering & Shipbuilding; Mitsubishi Heavy Industries;
Operators	Imperial Japanese Navy
Subclasses	Kaichū I (Ro-11 class); Kaichū II (Ro-13 class); Kaichū III (Ro-16 class); Kaichū IV (Ro-26 class); Toku-Chū/Kaichū V (Ro-29 class); Kaichū VI (Ro-33 class); Sen-Chū/Kaichū VII (Ro-35 class);
Built	1917-1944
In commission	1919-1945

The Kaichū type submarine (海中型潜水艦, Kaichū-gata sensuikan) submarines were double-hulled medium-sized submarines of the Imperial Japanese Navy during World War II. The name was derived from the Kaigun-shiki Chū-gata Sensuikan (海軍式中型潜水艦, Navy Medium Type submarine).

Several variants existed. From 1934 to 1944, the K6 type (Ro-33 Class) and the K7 type (Senchū, Ro-35 Class) were built. They were equipped with a 76.2 mm (3.00 in) L/40 gun and four 53 cm torpedo tubes for ten type 95 Long Lance torpedoes.

Most of these submarines were destroyed in combat, suffering from Allied anti-submarine warfare measures, and only Ro-50 survived the war.

Class overview
Name	Kaichū type submarines
Builders	Kure Naval Arsenal Sasebo Naval Arsenal Yokosuka Naval Arsenal Kawasaki Shipbuilding Mitsui Engineering & Shipbuilding Mitsubishi Heavy Industries
Operators	Imperial Japanese Navy
Subclasses	Kaichū I (Ro-11 class) Kaichū II (Ro-13 class) Kaichū III (Ro-16 class) Kaichū IV (Ro-26 class) Toku-Chū/Kaichū V (Ro-29 class) Kaichū VI (Ro-33 class) Sen-Chū/Kaichū VII (Ro-35 class)
Built	1917-1944
In commission	1919-1945