Japanese submarine I-63

The Japanese submarine I-63 was a cruiser submarine of the KD3B sub-class built for the Imperial Japanese Navy (IJN) during the 1920s. She was sunk in an accidental collision with her sister ship JAPANESE SUBMARINE I-60 with the loss of most of her crew in early 1939. The wreck was salvaged the next year and scrapped.

Design and description
The submarines of the KD3B sub-class were essentially repeats of the preceding KD3A sub-class with minor modifications to improve seakeeping. They displaced 1800 LT surfaced and 2300 LT submerged. The submarines were 101 m long, had a beam of 8 m and a draft of 4.9 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 KD3Bs 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 Sasebo Naval Arsenal, I-63 was launched on 28 September 1927 and completed on 20 December 1928. On 2 February 1939, the boat was sunk when she was accidentally rammed by her sister ship JAPANESE SUBMARINE I-60 in the Bungo Strait, off Kyushu, killing 81 aboard. Her captain and six crewmen were rescued. The wreck was salvaged the following year and scrapped in Kure.