Japanese submarine Ro-56 (1921)

The submarines of the Type L2 sub-class were close copies of the British L-class submarine built under license in Japan. They differed from the preceding L1 subclass in the deletion of the two broadside-firing torpedo tubes and the two torpedoes for them, the use of domestically produced diesel engines and batteries, and a different battery arrangement. They displaced 907 tonnes (893 long tons) surfaced and 1,093 tonnes (1,075.3 long tons) submerged. The submarines were 70.59 meters (231 ft 7 in) long and had a beam of 7.16 meters (23 ft 6 in) and a draft of 3.94 meters (12 ft 11 in). They had a diving depth of 60 meters (197 ft).

For surface running, the submarines were powered by two 1,200-brake-horsepower (895 kW) Vickers diesel engines, each driving one propeller shaft. When submerged, each propeller was driven by an 800-shaft-horsepower (597 kW) electric motor. They could reach 17.3 knots (32.0 km/h; 19.9 mph) on the surface and 10.4 knots (19.3 km/h; 12.0 mph) underwater. On the surface, they had a range of 5,500 nautical miles (10,200 km; 6,300 mi) at 10 knots (19 km/h; 12 mph); submerged, they had a range of 80 nmi (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph).

The submarines were armed with four internal 450 mm (18 in) torpedo tubes, all in the bow, and carried a total of eight Type 44 torpedoes. They were also armed with a single 76.2 mm (3 in) deck gun.

Ro-56 was laid down as Submarine No. 30 on 10 July 1920 by Mitsubishi at Kobe, Japan.[1] Launched on 11 May 1921,[1] she was completed and commissioned on 16 January 1922,[1] the final unit of the L2 subclass.

Upon commissioning, Submarine No. 30 was assigned to Submarine Division 4 — in which she spent her entire active career — in Submarine Squadron 1 in the 1st Fleet.[1] She was renamed Ro-56 on 1 November 1924.[1] Submarine Division 4 was attached to the Yokosuka Naval District on 1 December 1925, in which it remained for the remainder of Ro-56′s career.[1] Ro-56 was assigned that day to the Yokosuka Defense Division.[1] She was decommissioned and placed in reserve on 1 April 1926.[1]

Ro-56 was recommissioned on 1 August 1926, and was assigned to the Yokosuka Defense Division again that day, serving in that duty until 1 December 1927.[1] She later served in the Yokosuka Defense Division again from 30 November 1929 to 15 November 1934.[1]

Ro-56 was decommissioned and placed in the Fourth Reserve in the Yokosuka Naval District on 15 December 1938.[1] The Japanese struck her from the Navy list on 1 April 1940,[1] and that day she became a stationary hulk with the name Haisen No. 13.[1]

• "Rekishi Gunzō"., History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005, ISBN 4-05-603890-2
• The Maru Special, Japanese Naval Vessels No.43 Japanese Submarines III, Ushio Shobō (Japan), September 1980, Book code 68343-44
• The Maru Special, Japanese Naval Vessels No.132 Japanese Submarines I "Revised edition", Ushio Shobō (Japan), February 1988, Book code 68344-36
• The Maru Special, Japanese Naval Vessels No.133 Japanese Submarines II "Revised edition", Ushio Shobō (Japan), March 1988, Book code 68344-37