Ha-201-class submarine
The were a class of small submarines designed for the Imperial Japanese Navy (IJN). They were first deployed in 1945, but never saw combat. The Ha-201's were designed from the outset to have high underwater speed and were based on the earlier Submarine No.71 prototype. The official designation of the submarine was . The type name, was shortened to . Design and description. At the end of 1944, the Imperial Japanese Navy decided it needed large numbers of high-speed coastal submarines to defend the Japanese Home Islands against an anticipated Allied invasion (named Operation Downfall by the  Allies). To meet this requirement, the "Ha-201"-class submarines were designed as small, fast submarines incorporating many of the same advanced ideas implemented in the German Type XXI and Type XXIII submarines. They were capable of submerged speeds of almost . The "Ha-201" class displaced surfaced and submerged. The submarines were long, had a beam of and a draft of . For surface running, the submarines were powered by a single diesel engine that drove one propeller shaft. When submerged the propeller was driven by a electric motor. They could reach on the surface and submerged. On the surface, the "Ha-201"-class submarines had  a range of at ; submerged, they had a range of at . Their armament consisted of two torpedo tubes with four torpedoes and a single mount for a 7.7-millimeter machine gun. Construction. The Japanese planned to build 79 "Ha-201"-class submarines (Submarines No. 4911 through 4989) under the Maru Sen Programme, prefabricating large sections of the boats, then completing them on the slipway. This was an ambitious goal considering the U.S. bombing campaign, which disrupted Japanese production, and by the time hostilities ceased on 15 August 1945 the Japanese had laid down only 22 submarines and completed only ten. Service. None  of the submarines made operational patrols. Except for one submarine that was wrecked, the Allies after the war scuttled all the submarines that had been completed as well as all the incomplete ones that had been launched. Those which remained on the building ways at the end of the war were scrapped incomplete. See also. Comparable submarines