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 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 surfaced and submerged. The submarines were long, had a beam of and a draft of . The boats had a diving depth of and a complement of 60 officers and crewmen.
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the KD3Bs had a range of at ; submerged, they had a range of at .
The boats were armed with eight internal 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 deck gun for combat on the surface.
Construction and commissioning.
"I-63" was built by the Sasebo Naval Arsenal at Sasebo, Japan. Her keel was laid on 12 August 1926 and she was launched on 28 September 1927. She was completed and commissioned on 20 December 1928.
Service history.
Upon commissioning, "I-63" was assigned to Submarine Division 28, in which she spent her entire career. The division was assigned to the Sasebo Naval District on 24 December 1929, then was reassigned to Submarine Squadron 2 in the 2nd Fleet in the Combined Fleet on 1 December 1930, to Submarine Squadron 1 in the 1st Fleet in the Combined Fleet on 1 December 1932, and to the Sasebo Defense Division in the Sasebo Naval District on 15 November 1933. On 20 March 1934, "I-63" was decommissioned and placed in reserve, and while she was in reserve Submarine Division 28 was reassigned to the Sasebo Guard Squadron on 15 November 1934.
Submarine Division 30 again was assigned to Submarine Squadron 2 in the 2nd Fleet on 15 November 1934, and "I-63" was recommissioned that day. On 7 February 1935, she departed Sasebo for a training cruise in the Kurile Islands. The cruise concluded with her arrival at Sukumo Bay on 25 February 1935. She got underway from Sasebo on 29 March 1935 for a training cruise in Chinese waters and returned to Sasebo on 4 April 1935. On 15 November 1935, Submarine Division 28 again was assigned to Submarine Squadron 1 in the 1st Fleet.
On 27 March 1937, "I-63" put to sea from Sasebo for a training cruise in the vicinity of Tsingtao, China. She concluded it with her arrival at Ariake Bay on 6 April 1937. Submarine Division 28 was reassigned to the Sasebo Defense Squadron in the Sasebo Naval District on 1 December 1937 and then to Submarine Squadron 1 in the 1st Fleet on 15 December 1938. 
Loss.
In January 1939, "I-63" got underway for fleet exercises. During the exercises, "I-63"′s sister ship, the submarine , accidentally rammed her on 2 February 1939 in the Bungo Strait off Kyushu. "I-63" sank with the loss of 81 men. Her commanding officer and six crewmen were rescued.
Pending salvage, "I-63" was reassigned for administrative purposes to the Fourth Reserve in the Sasebo Naval District, effective on the date she sank. Her wreck was salvaged in January 1940 and scrapped in Kure. She was stricken from the Navy list on 1 June 1940.