Ha-101-class submarine explained

The was a transport submarine built for the Imperial Japanese Navy (IJN) during World War II. The IJN planned to build 12 boats, but only 10 vessels were completed by the end of the war. The IJN called these submarines . The type name, was shortened to .^[1]

Several boats were converted to tankers or mother ships for the midget submarines.

Design and description

The Ha-101-class submarines were designed as small, cheap transport submarines to resupply isolated island garrisons. They displaced 429LT surfaced and 493LT submerged. The submarines were 44.5m (146feet) long, had a beam of 6.1m (20feet) and a draft of 4.04m (13.25feet). They were designed to carry 600NaN0 of cargo.^[2]

For surface running, the boats were powered by a single 4000NaN0 diesel engine that drove one propeller shaft. When submerged the propeller was driven by a 140hp electric motor. They could reach 10kn on the surface and underwater.^[3] On the surface, the Ha-101s had a range of 3000nmi at ; submerged, they had a range of 46nmi at . The boats were armed a single mount for a 250NaN0 Type 96 anti-aircraft gun.^[4]

Planned construction

Project number S57. In February 1944, the IJN planned a small-size transport submarine, the IJA planned the Maru Yu.

Boats

Boat #	Name	Builder	Laid down	Launched	Completed	Decommissioned	Fate
4601	^[5]	Kawasaki-Senshū Shipyard, Kawasaki-Kōbe Shipyard	08-06-1944	22-08-1944	22-11-1944	15-09-1945	Converted to a tanker submarine in June 1945;^[6] scuttled off Shimizu City October 1945
4602		Kawasaki-Senshū Shipyard, Kawasaki-Kōbe Shipyard	08-06-1944	22-08-1944	06-12-1944	15-09-1945	Converted to a tanker submarine in June 1945; scuttled off Shimizu City October 1945
4603		Kawasaki-Senshū Shipyard, Kawasaki-Kōbe Shipyard	29-06-1944	21-10-1944	03-02-1945	30-11-1945	Converted to a radar picket submarine April 1945; re-converted to a tanker submarine in June 1945; scuttled off the Gotō Islands 01-04-1946
4604		Kawasaki-Kōbe Shipyard	01-07-1944	30-09-1944	01-12-1944	15-09-1945	Converted to a tanker submarine June 1945; scuttled off Shimizu City October 1945
4605		Kawasaki-Senshū Shipyard, Kawasaki-Kōbe Shipyard	29-06-1944	31-10-1944	19-02-1945	30-11-1945	Converted to a radar picket submarine in March or April 1945; re-converted to a tanker submarine in June 1945; scuttled off the Gotō Islands 01-04-1946
4606		Mitsubishi-Kōbe Shipyard	01-07-1944	30-10-1944	15-12-1944	30-11-1945	Converted to Kōryū mother ship June 1945; scuttled off the Gotō Islands 01-04-1946
4607		Mitsubishi-Kōbe Shipyard	01-08-1944	20-12-1944	20-03-1945	30-11-1945	Converted to Kōryū mother ship June 1945; scuttled off the Gotō Islands 01-04-1946
4608		Kawasaki-Senshū Shipyard, Kawasaki-Kōbe Shipyard	05-09-1944	28-12-1944	06-05-1945	30-11-1945	Converted to Kōryū mother ship June 1945; scuttled off the Gotō Islands 01-04-1946
4609		Mitsubishi-Kōbe Shipyard	01-08-1944	10-01-1945	10-03-1945	30-11-1945	Converted to 's tender July 1945; scuttled off the Gotō Islands 01-04-1946
4610	Ha-110	Kawasaki-Senshū Shipyard, Kawasaki-Kōbe Shipyard	05-09-1944	12-01-1945			95% complete; scuttled in the Kii Channel 15-04-1946
4611		Mitsubishi-Kōbe Shipyard	16-11-1944	02-03-1945	13-07-1945	30-11-1945	scuttled off the Gotō Islands 01-04-1946
4612	Ha-112	Mitsubishi-Kōbe Shipyard	16-11-1944	15-04-1945			95% complete; scuttled in the Kii Channel 15-04-1946

Bibliography

Book: Bagnasco, Erminio . Submarines of World War Two . 1977 . Naval Institute Press . Annapolis, Maryland . 0-87021-962-6.
Book: Carpenter. Dorr B.. Polmar. Norman. Submarines of the Imperial Japanese Navy 1904–1945. 1986. Conway Maritime Press. London. 0-85177-396-6. amp.
Book: Conway's All the World's Fighting Ships 1922–1946. Chesneau. Roger. Conway Maritime Press. Greenwich, UK. 1980. 0-85177-146-7.
Web site: Rekishi Gunzō., History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005,
Ships of the World special issue Vol.37, History of Japanese Submarines, Web site: Kaijinsha., (Japan), August 1993
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
Senshi Sōsho Vol.88, Naval armaments and war preparation (2), "And after the outbreak of war", Asagumo Simbun (Japan), October 1975

Notes and References

The read as "Sen'yu-Shō", but the read as "Sen'yu-Ko-gata" in Japanese.
Carpenter & Dorr, p. 140
Chesneau, p. 204
Bagnasco, p. 195
. The same shall apply hereinafter.
Senshi Sōsho Vol.88 (1975), p.272 - 273