NAVYPEDIA

Photo

I121  

Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
伊21 [I21] (ex-第48号艦 [48-go]), 6.1938- 伊121 [I121]			Kawasaki, Kobe	1/1924	30.3.1926	3.1927	surrendered 8.1945, BU 1946
伊22 [I22] (ex-第49号艦 [49-go]), 6.1938- 伊122 [I122]			Kawasaki, Kobe	10/1924	8.11.1926	10.1927	sunk 10.6.1945
伊23 [I23] (ex-第50号艦 [50-go]), 6.1938- 伊123 [I123]			Kawasaki, Kobe	10/1924	19.3.1927	4.1928	sunk 29.8.1942
伊24 [I24] (ex-第60号艦 [60-go]), 6.1938- 伊124 [I124]			Kawasaki, Kobe	10/1924	12.12.1927	12.1928	sunk 20.1.1942

Technical data

Displacement standard, t	1142
Displacement normal, t	1383 / 1768
Length, m	82.0 wl 85.2 oa
Breadth, m	7.52
Draught, m	4.42
No of shafts	2
Machinery	2 MAN diesels / 2 electric motors
Power, h. p.	2400 / 1100
Max speed, kts	14.5 / 7
Fuel, t	diesel oil 154
Endurance, nm(kts)	10500(8) / 40(4.5)
Armament	1 x 1 - 140/40 11-shiki, 4 - 533 TT (bow,12), 42 mines
Complement	51 - 70
Diving depth operational, m	75

Standard scale images

Graphics

Project history

Kirai-Sen (Minelaying submarine) type. Unique Japanese purpose-built minelaying submarines. Drawings of the former German submarine U125 received by Japan on a reparation and commissioned by the IJN as О1 were put in a design basis. Double-hulled, endurance was about 20 days. Submarines were built under the 1919 programme. They have appeared unsuccessful because of whimsical system of a minelaying and insufficient longitudinal stability in submerged position. Projected I25 and 26 (ex-Nos52 and 63) were cancelled in 1924.

In 1940 they were fitted with tanks for aviation petrol and then could be used for a refuelling of flying boats at a great distance from bases.

Modernizations

1940, all: were converted to refueling of large flying boats, petrol tanks were fitted on deck.

Naval service

I121 and I122 since August, 1943 were used for training.

I124 was sunk 20.1.1942 near Darwin by US escort destroyer Edsall and Australian minesweepers Deloraine, Katoomba and Lithgow. I123 was sunk 29.8.1942 SE off Savo by US destroyer Gamble. I122 was sunk 10.6.1945 by US submarine Skate in Toyama Bay (Honshu).