Japanese submarine I-55 (1925)

The Japanese submarine I-55 was a cruiser submarine of the KD3A sub-class built for the Imperial Japanese Navy (IJN) during the 1920s.

Design and description
The submarines of the KD3A sub-class were the first Japanese-designed cruiser submarines, based on experience with earlier designs based on British and German cruiser submarines. They displaced 1800 LT surfaced and 2300 LT submerged. The submarines were 100 m long, had a beam of 8 m and a draft of 4.82 m. The boats had a diving depth of 60 m and a complement of 60 officers and crewmen.

For surface running, the boats were powered by two 3400 bhp diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 900 hp electric motor. They could reach 20 kn on the surface and 8 kn underwater. On the surface, the KD3As had a range of 10000 nmi at 10 kn; submerged, they had a range of 90 nmi at 3 kn.

The boats were armed with eight internal 53.3 cm torpedo tubes, six in the bow and two in the stern. They carried one reload for each tube; a total of 16 torpedoes. They were also armed with one 120 mm deck gun for combat on the surface.

Construction and career
Built by the Kure Naval Arsenal, I-55 was laid down on 1 April 1924 as Submarine No. 78 and renamed I-55 on 1 November. The boat was launched on 2 September 1925 and completed on 5 September 1927. During a training exercise on 11 July 1929, she accidentally collided with her target, the heavy cruiser JAPANESE CRUISER Kinugasa, and damaged her bow plating. On 10 February 1932, she was slightly damaged when she was accidentally rammed by her sister ship, JAPANESE SUBMARINE I-54.