Type A-class


  (National Museum of the Pacific War)

The Ko-Hyoteki (Target A) Ko Gata (Type A ) midget submarine was equipped with an electric motor driven by 224 two-volt batteries. The Type A class could reach 19 knots submerged. They carried two bow 17.7-inch torpedoes. Fifty boats (HA-3 thru HA-52) were completed before the end of the war and were used against Allied warships and shipping in the 7 December 1941 Pearl Harbor attack and May 1942 raids on Sydney, Australia and Diego Suarez, Madagascar. Midgets were also used in attacks off Guadalcanal in 1942-43 and as defensive units in the Aleutians and elsewhere in the Pacific.

After Pearl Harbor, modifications were made to the Type A designed and this variant was designated Type A Kai 1 (improved version 1). The modifications included the fitting of an improved gyro compass, serrated net-cutters on the bow and conning tower, a sled-like bow guard for maneuvering over obstacles and a propeller guard to prevent entanglement in nets or cables. The Sydney, Diego Suarez and Guadalcanal midget submarines were of this type.

The Otsu Gata (Type B) midget submarine was the first version fitted with a diesel (40 hp / 25 kw) and a slightly longer hull to accommodate it. All specifications were same as the Type A, except the length (24.9 m vs. 23.9 m), displacement (47 tons vs. 46), and surface speed (6 knots vs. 19). The Type B's diesl engine allowed a range of 500 nautical miles (nms) at 6 knots (surfaced), 15.8 nms at 9 knots and 84 nms at 6 knots underwater on the electric motor.

Four Type A midgets are on display around the world. They are located at:
- National Museum of the Pacific War, Fredericksburg, Texas
- Nautilus Memorial Submarine Force Library and Museum, Groton, Connecticut
- JMSDF Naval Tactical School No. 1, Eta Jima, Hiroshima, Japan
- Australian War Memorial, ANZAC Hall, Canberra

Units 50
Years Completed 1940-1943
Displacement 46 tons submerged
Dimensions 78.5 ft x 10.2 ft x 6 ft (dia.)
Machinery 1 electric motor: 600 hp; two counter-rotating screws on a single shaft,

Speed 23 knots / 19 knots
Range 15.8 nm at 9 knots/ 84 nm at 6 knots
Armament 2x 17.7-inch (457mm) TT fwd + (2 torpedoes).
Max. Depth 100 m
Crew 2

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Type A-class
  * Ha-19


Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 1 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 2 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 3 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 4 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 5 of 7
Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 1 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 2 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 3 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 4 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 5 of 7
Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 6 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 7 of 7Pearl Harbor chart found in Japanese submarine Ha-19Ha-19 salvage, bow viewHa-19 salvage, conning tower, starboard side
Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 6 of 7Ha-19 beached on Oahu, US Territory of Hawaii, 8 Dec 1941, photo 7 of 7Pearl Harbor chart found in Japanese submarine Ha-19Ha-19 salvage, bow viewHa-19 salvage, conning tower, starboard side

See all 29 photos of Type A-class on WW2DB






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