fighting ships of the world



"Kaidai 1" 1 class submarine (1924)

I51 1924

Name No Yard No Builder Laid down Launched Comp Fate
第44号艦 [44-go], 11/1924- 伊51 [I51]     Kure K K 1921 29/11/1921 6/1924 stricken 1941


Displacement standard, t


Displacement normal, t

1500 / 2430

Length, m

87.0 pp 91.4 oa

Breadth, m


Draught, m


No of shafts



4 Sulzer diesels / 4 electric motors

Power, h. p.

5200 / 2000

Max speed, kts

20 / 10

Fuel, t

diesel oil 160

Endurance, nm(kts) 20000(10) / 100(4)

1 x 1 - 120/45 11-shiki, 1 x 1 - 76/40 3-go, 8 - 533 TT (6 bow, 2 stern, 24)

Sensors K-chubu hydrophone



Diving depth operational, m


Ship project history: Kaidai 1 (Large Admiralty 1) type. Under the "8-8" programme building of several large submarines for joint operations with battle forces at a great distance from bases was provided. According to Naval staff requirements (10000nm endurance, raised seaworthiness, max surface speed not less than 20kts) in 1919 Naval technical department has started designing of 1500t submarine cruiser. Difficulties which have arisen at designing of so large submarine, have compelled Japanese designers to use British and German experience. For the fullest account of merits and demerits of each of shipbuilding schools it has been decided to build two experimental submarines. As a prototype for the first of them (Kaidai 1) RN cruiser submarine of "K" class (with replacement of a steam turbine by diesels), and for second (Kaidai 2) German submarine cruiser U139 should serve. Double-hulled.

Comparative trials of I51 and I52 have revealed preferable characteristics of the latter, in particular, she was faster, possessed better seaworthiness, and her engine has appeared more reliably. However I51 had higher endurance and carried more torpedoes.

Modernizations: 1932: 2 shafts were removed, engine power was 2600 / 1000hp, maximal speed 14.5 / 6.2kts; - 1 x 1 - 76/40; + 1 seaplane (E6Y)

1933: + catapult

Naval service: I51 was used for training in 1930-1939.



Ivan Gogin, 2008-14