Ha-202 in 1945
Class overview
Name	Ha-201 class submarine
Builders	Sasebo Naval Arsenal Kawasaki Shipbuilding Corporation Mitsubishi Heavy Industries
Operators	Imperial Japanese Navy
Preceded by	Vessel Number 71
Built	1945
In commission	1945
Planned	79
Completed	9 + 1 (after the end of war)
Retired	10
General characteristics
Type	Submarine
Displacement	320 long tons (325 t) surfaced 440 long tons (447 t) submerged
Length	53.00 m (173 ft 11 in) overall
Beam	4.00 m (13 ft 1 in)
Draft	3.44 m (11 ft 3 in)
Propulsion	1 × intermediate diesel 400 bhp surfaced 1,250 shp submerged single shaft
Speed	11.8knots (21.9 km/h) surfaced 13.9 knots (25.7 km/h) submerged
Range	3,000 nmi (5,600 km) at 10 knots (19 km/h) surfaced 105 nmi (194 km) at 2 knots (3.7 km/h) submerged
Test depth	100 m (330 ft)
Complement	26
Armament	2 × 533 mm (21 in)torpedo tubes 4 ×Type 95 torpedoes 1 × 7.7 mm machine gun

TheHa-201-class submarine (波二百一型潜水艦,Ha-ni-hyaku-ichi-gata sensuikan) were a class of small submarines designed for theImperial 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 earlierSubmarine No.71 prototype. The official designation of the submarine wasSentaka-Shō type submarine (潜高小型潜水艦,Sen-Taka-Ko-gata sensuikan, "Submarine High speed-Small type"). The type name was shortened to SuichūKōsokuSensuikanKo-gata (水中高速潜水艦小型,Underwater High speed Submarine Small type).^[1]

At the end of 1944, the Imperial Japanese Navy decided it needed large numbers of high-speed coastal submarines to defend theJapanese Home Islands^[2] against an anticipatedAllied invasion (namedOperation Downfall by the Allies). To meet this requirement, theHa-201-class submarines were designed as small, fast submarines^[2] incorporating many of the same advanced ideas implemented in the GermanType XXI andType XXIII submarines. They were capable of submerged speeds of almost 14 knots (26 km/h; 16 mph).^[2]

TheHa-201 classdisplaced 325 metric tons (320 long tons) surfaced and 447 metric tons (440 long tons) submerged.^[2] The submarines were 53 meters (173 ft 11 in) long, had abeam of 4.00 meters (13 ft 1 in) and adraft of 3.44 meters (11 ft 3 in).^[2] For surface running, the submarines were powered by a single 400-brake-horsepower (298 kW)diesel engine that drove onepropeller shaft.^[2] When submerged the propeller was driven by a 1,250-shaft-horsepower (932 kW)electric motor.^[2] They could reach 11.8knots (21.9 km/h; 13.6 mph) on the surface and 13.9 knots (25.7 km/h; 16.0 mph) submerged.^[2] On the surface, theHa-201-class submarines had a range of 3,000nautical miles (5,600 km; 3,500 mi) at 10 knots (19 km/h; 12 mph); submerged, they had a range of 105 nmi (194 km; 121 mi) at 2 knots (3.7 km/h; 2.3 mph).^[2] Their armament consisted of two 533-millimeter (21 in)torpedo tubes with fourtorpedoes and a single mount for a 7.7-millimetermachine gun.^[2]

The Japanese planned to build 79Ha-201-class submarines (Submarines No. 4911 through 4989) under theMaru 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 hadlaid down only 22 submarines^[2] and completed only ten.^[2]

None of the submarines made operational patrols.^[2] Except for one submarine that was wrecked, the Allies after the warscuttled 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.

Comparable submarines

• German Type XXIII submarine
• I-201 class submarine
• Vessel Number 71
• Kairyū-class submarine

• "Rekishi Gunzō"., History of Pacific War Vol.17 I-Gō Submarines,Gakken (Japan), January 1998,ISBN 4-05-601767-0
• Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005,ISBN 4-05-603890-2
• 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,"Kaijinsha"., (Japan), August 1993

• Submarine classes
• Submarines of the Imperial Japanese Navy
• Japan campaign

• Articles containing Japanese-language text
• Articles with short description
• Short description matches Wikidata
• Use dmy dates from January 2018