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, Potsdam Declaration, when it was dissolved followin ...
(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
''Submarine No.71'' (Number 71) was an experimental high-speed submarine built for the Imperial Japanese Navy (IJN) during the 1930s.
Design and description
Submarine ''No.71'' was designed to test high-speed performance underwater. Intended to ...
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 is an archipelago of 14,125 islands that form the country of Japan. It extends over from the Sea of Okhotsk in the northeast to the East China and Philippine seas in the southwest along the Pacific coast of the Eurasian continent, and cons ...
against an anticipated
Allied invasion (named
Operation Downfall
Operation Downfall was the proposed Allied plan for the invasion of the Japanese home islands near the end of World War II. The planned operation was canceled when Japan surrendered following the atomic bombings of Hiroshima and Nagasaki ...
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
Beam may refer to:
Streams of particles or energy
*Light beam, or beam of light, a directional projection of light energy
**Laser beam
*Radio beam
*Particle beam, a stream of charged or neutral particles
**Charged particle beam, a spatially lo ...
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 v ...
of .[ For surface running, the submarines were powered by a single ]diesel engine
The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...
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, torque, and rotation, usually used to connect o ...
.[ When submerged the propeller was driven by a ]electric motor
An electric motor is a 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 electromagnetic coil, wire winding to gene ...
.[ 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, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such ...
es 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
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 ...
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 act of deliberately sinking a ship by allowing water to flow into the hull, typically by its crew opening holes in its hull.
Scuttling may be performed to dispose of an abandoned, old, or captured vessel; to prevent the vesse ...
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
See also
Comparable submarines
*German Type XXIII submarine
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 ...
*I-201 class submarine
The were submarines of the Imperial Japanese Navy during World War II. These submarines were of advanced design, built for high underwater speed, and were known as or . The type name, was shortened to .
They were one of the fastest submarine c ...
* Vessel Number 71
*
Bibliography
*'', History of Pacific War Vol.17 I-Gō Submarines'', Gakken
is a Japanese publishing company founded in 1947 by Hideto Furuoka, which also produces educational toys. Their annual sales are reported at ¥ 90 billion ($789 million US).
Gakken publishes educational books and magazines and produces othe ...
(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