RO-33 showing bow anti-submarine net cutter.
These double-hull medium displacement boats were derived from the Kai-toku-chu (KT) type. They were constructed at four shipyards in two variants, K.5 (RO-33 class) and K.6 (RO-35 class), from 1934 to 1944. The later and more numerous K.6 variant was armed with the 21-inch oxygen-propelled Type 95 submarine torpedo and a 3.25-inch (80-mm) deck gun. Allied ASW measures took a heavy toll of the type. RO-50 was the only ship of the type to survive the war and was surrendered at Sasebo.
2 electric motors: 1,200 hp