Japanese submarines I 15 class

Japanese submarine class of the Second World War.
History, development, service, specifications, pictures and 3D model.

submarine I 19
Japanese submarine I 19 of I 15 class

I 15 submarine class (20 subs).
Japanese submarine class, launched 1939-1942.


These Japanese submarines, designated Type B, were scouting craft designed to work in conjunction with the Type A headquarters submarines. They were developed from the Type KD6 and construction was carried out parallel with that of the Type A and Type C submarine.

For scouting the I 15 Class submarines carried a single float plane stowed in sections inside a small circular hangar extending forward of the conning tower. On the deck casing forward of the hangar there was a catapult reaching almost to the bows.

In order to simplify design and construction and to speed delivery of the boats, as many aspects of the design equipment as possible were made common to all three types. Machinery was thus identical to the Type A I9 Class, though bunkerage was reduced and the radius of action was thus 2000 nautical miles less. Armament was the same as in I9 Class, except that only 17 torpedoes were carried.

Japanese sub I 15
I 15 during service as a supply vessel, with two Daihatsu tracked landing boats loaded on her deck. Ships in this class were modified during the war to take four or six Kaiten one-man suicide torpedoes for kamikaze missions against US warships.
Initially only six submarines (I 15 – I 25) were ordered to this design under the 1937 Program, but under the 1939 Program a further 14 vessels were ordered. The boats entered service between September 1940 and April 1943 having been built at Kure navy yard (I 15, I 26, I 30, I 37), Yokosuka navy yard (I 17, I 23, I 29, I 31, I 36), Mitsubishi­ Kobe (I 19, I 25, I 28, I 33, I 35), Kawasaki­ Kobe (I 21) and Sasebo navy yard (I 27, I 32, I 34, I 38, I 39).

During the war a number of units had a 140-mm (5.5-in) gun added in front of the conning tower to enable the boats to act as attack submarines. Towards the end of 1944 I36 and I37 were modified to carry four Kaiten suicide submarines.

Animated 3D model of Japanese submarine I 19 of the I 15 class

Specifications for I 15 class


I 15 classspecification
Displacement 2,584 tons surfaced; 3,654 tons submerged
Length 356 ft 6 in
Bream 30 ft 6 in
Draught 16 ft 9 in
Machinery 2-shaft diesels, 2 electric motors
Power 12,400 hp surfaced; 2,000 hp submerged
Speed 23.8 kts surfaced; 8 kts submerged
Range 14,000 nm surfaced; 30 nm submerged


I 15 classspecification
Main Armament 6 x 21-in torpedo tubes with 17 torpedoes
Secondary Armament 1 x 5.5-in gun
Anti-Aircraft 2 x 1-in guns
Aircraft 1 floatplane

Service Statistics:

I 153/1939war loss 2/11/42
I 177/1939war loss 19/8/43
I 199/1939war loss 25/11/43
I 212/1940war loss 29/11/43
I 2311/1939marine casualty 14/2/42
I 256/1940war loss 3/9/43
I 264/1940marine casualty 25/10/44
I 276/1940war loss 12/2/44
I 2812/1940war loss 17/5/42
I 299/1940war loss 26/7/44
I 309/1940war loss 13/10/42
I 313/1941war loss 12/5/43
I 3212/1940war loss 24/4/44
I 335/1941marine casualty 13/6/44
I 349/1941war loss 13/11/43
I 359/1941war loss 22/11/43
I 3611/1941surrendered and scuttled
I 3710/1941war loss 19/11/44
I 384/1942war loss 12/11/44
I 394/1942war loss 26/11/43

References and literature

Fighting Ships of the World (Antony Preston)
Kriegsschiffe von 1900 bis heute – Technik und Einsatz (Buch und Zeit Verlagsgesellschaft)
The Illustrated Directory of Warships from 1860 to the present day (David Miller)
Kriegsschiffe 1939-45 (Heyne-Bildpaperback)
Flotten des 2. Weltkrieges (Antony Preston)
U-Boote seit 1919 (Antony Preston, John Batchelor)
The Encyclopedia of Weapons of World War II (Chris Bishop)

for sharing:

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top