NAVYPEDIA

Photo

A type

Ships

Names	Builders	Commissioned	Losses	Transfers	Discarding
"A-Hyoteki": 第1号艦 [1-go] 第2号艦 [2-go] "Ko-Hyoteki":  波1 - 52 [HA1 - 52] 波54 - 61 [HA54 - 61]	Mitsubishi, Yokohama: 1-go Kure K K: 2-go, HA1, 2 Ourazaki, Kure: HA3 - 52, 54 - 61	1934: 1-go, 2-go 1936: HA1, 2 1938 - 1942: HA3 - 52, 54 - 61	4 boats (7.12.1941), 3 boats (30.5.1942), 4 boats (31.5.1942), HA8, HA22, HA38 and 5 other boats (1942), 3 boats (1942 - 1943)	none	all survived: surrendered 8.1945 and BU

Technical data

Displacement standard, t
Displacement normal, t	/ 45.3
Length, m	23.9
Breadth, m	1.85
Draught, m	1.85
No of shafts	1
Machinery	1 electric motor
Power, h. p.	600
Max speed, kts	19 - 24
Fuel, t	none
Endurance, nm(kts)	80(6) / 80(6)
Armament	2 - 450 TT (bow, 2)
Complement	2
Diving depth operational, m

Standard scale images

Graphics

Project history

Works on midget submarines have begun in Japan in 1933. According to Naval Staff plans midget submarines were supposed to use for attack of enemy bases and anchorages. To a site of operation they should be carried by specialised carrier submarines. In the conditions of the strict privacy two experimental midgets were built in 1934. For concealment of true assignment of boats they were officially classified as "target submarines" (A-Hyoteki). On results of trials in the project necessary improvements were brought, then serial building of midget submarines under designation Ko-Hyoteki has been developed. As carriers seaplane carriers Chiyoda and Chitose and Hei-Gata (C) type submarines were arranged.

At designing the basic thrust became on achievement of a high submerged speed. For this purpose submarines received powerful (for so small ship) electric motor, and hull have given streamlined spindle-shaped form. This combination has ensured to first Ko-Hyoteki submarines 23kts submerged speed (subsequent boats because of the brought modificatons reached 18-19kts). Two 450mm TTs placed in a bow one over another were basic weapon. First two submarine had no CT.

Modernizations

None.

Naval service

Unfortunately, the information about fates of Japanese midget submarines had scrappy and frequently inconsistent character. It is known, that during an attack to Pearl Harbor 7.12.1941 5 midgets of A type were lost. 3 more boats of this type were lost 30.5.1942 in Diego Suarez area and 4 in Sydney harbour 31.5.1942. During battles at Solomons in 1942 8 midgets of A type were lost (including НA8, 22 and 38). 3 more A type boats were lost off Aleutian in 1942-1943.