The were a class of small submarines designed for the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrend ...

(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 .The read as "Sentaka-Shō", but the read as "Sentaka-Ko-gata", read as "Kō-soku" and read as "Ko-gata" in Japanese.

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 The Japanese archipelago (Japanese: 日本列島, ''Nihon rettō'') is a group of 6,852 islands that form the country of Japan, as well as the Russian island of Sakhalin. It extends over from the Sea of Okhotsk in the northeast to the East Chin ...

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 German Type XXIII submarines were the first so-called elektroboote ("electric boats") to become operational. They were small coastal submarines designed to operate in the shallow waters of the North Sea, Black Sea and Mediterranean Sea, where l ...

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 Draft, The Draft, or Draught may refer to: Watercraft dimensions * Draft (hull), the distance from waterline to keel of a vessel * Draft (sail), degree of curvature in a sail * Air draft, distance from waterline to the highest point on a vesse ...

of . For surface running, the submarines were powered by a single

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...

that drove one

propeller shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect ...

. When submerged the propeller was driven by a

electric motor An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate for ...

. 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 tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s with four

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, s ...

es and a single mount for a 7.7-millimeter

machine gun A machine gun is a fully automatic, rifled autoloading firearm designed for sustained direct fire with rifle cartridges. Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles) ar ...

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 Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one o ...

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 Scuttling is the deliberate sinking of a ship. Scuttling may be performed to dispose of an abandoned, old, or captured vessel; to prevent the vessel from becoming a navigation hazard; as an act of self-destruction to prevent the ship from being ...

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.

Boats

Footnotes

Bibliography

*'', History of Pacific War Vol.17 I-Gō Submarines'', Gakken (Japan), January 1998, *''Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces"'', Gakken (Japan), March 2005, *''The Maru Special, Japanese Naval Vessels No.43 Japanese Submarines III'', Ushio Shobō (Japan), September 1980, Book code 68343-43 *''The Maru Special, Japanese Naval Vessels No.132 Japanese Submarines I "Revised edition"'', Ushio Shobō (Japan), February 1988, Book code 68344-36 *''Ships of the World special issue Vol.37, History of Japanese Submarines'', , (Japan), August 1993 {{WWII Japanese ships Ha-201 Ha-201 Japan campaign

Design and description

Construction

Service

Boats

Footnotes

See also

Bibliography