fighting ships of the world



"Sen-Toku" submarine aircraft carriers (1944-1945)

I400 1945

Name No Yard No Builder Laid down Launched Comp Fate
400 [I400]     Kure K K 1/1943 18/1/1944 12/1944 surrendered 8/1945, scuttled 4/6/1946
401 [I401]     Sasebo K K 4/1943 11/3/1944 1/1945 surrendered 8/1945, scuttled 31/5/1946
402 [I402]     Sasebo K K 10/1943 5/9/1944 7/1945 surrendered 8/1945, scuttled 1/4/1946
403 [I403]     Kure K K 4/1943 --- --- cancelled 3/1945
404 [I404]     Kure K K 11/1943 7/7/1944 --- cancelled 3/1945, sunk 28/7/1945
405 [I405]     Kawasaki, Kobe 9/1944 --- --- cancelled 3/1945


Displacement standard, t


Displacement normal, t

5223 / 6560

Length, m

116.0 pp 120.1 wl 122.0 oa

Breadth, m


Draught, m


No of shafts



4 MAN diesels / 4 electric motors

Power, h. p.

7700 / 2400

Max speed, kts

18.7 / 6.5

Fuel, t

diesel oil 780

Endurance, nm(kts) 30000(16) / 60(3)

1 x 1 - 140/40 11-shiki, 3 x 3 - 25/60 96-shiki, 1 x 1 - 25/60 96-shiki, 8 - 533 TT (bow, 20), 1 catapult, 3 seaplanes (M6A1)

Electronic equipment

2-shiki 2-go, 3-shiki 1-go radars, 93-shiki sonar, 93-shiki hydrophone, E27 ECM suite



Diving depth operational, m 100

Ship project history: Sen-Toku (Special submarine) type. Unique ships which did not have analogues in other navies. Largest submarines of pre-nuclear era. Their occurence was obliged to a plan of admiral Yamamoto to attack locks of Panama canal by seaplanes. Attack seaplane Aichi M6A Seiran has been created to this role. Being much more largely than existing reconnaissance seaplanes, it can be not carried in the standard hangars, therefore specially for these aircraft there has been begun designing of specialised submarine (Sen-Toku). At designing work experience of creation of Kai-Ko-Taka AM class submarines was used. It was originally supposed to build 4550t submarine, carrying two seaplanes, but subsequently air group have decided to increase to three planes that has led to growth of displacement to 5223t.

Submarine was actually designed around the cylindrical hangar with 34m length and slightly shifted to starboard (CT, as well as the crane for handling aircrafts, to portside). Construction was double-hulled, and pressure hull has been fulfilled from two horizontal cylinders adjoint into the form of horizontally laid "8". Endurance was about 90 days. Torpedo armament repeated accepted on Hei-Gata: 8 TTs took places on four in two compartments separated from each other one over another.

Under the additional programme of 1942 six submarines of "special type" have been ordered. To end of war three were completed, last was completed as a supply tanker-submarine (by another sources, she was completed as seaplane carrier and conversion to tanker was begun but not finished), and she had no aviation. Building of three remaining was suspended in March, 1945, (I404 was in 95% availability). Planned I406-417 were never begun.

Modernizations: None.

Naval service: I402 was damaged 11/8/1945 by US carrier aircraft at Kure, scuttled by Americans 1/4/1946. I401 in early 1945 was damaged on a mine, scuttled by Americans 31/5/1946. I400 was scuttled by Americans 4/6/1946. Unfinished I404 was sunk 28/7/1945 at Kure by US carrier aircraft.

I401 1945


Ivan Gogin, 2008-14