Ro-24, originally named Submarine No. 42, was an Imperial Japanese Navy Kaichū-Type submarine, the lead unit of the Kaichū III subclass. She was commissioned in 1920 and operated in the waters of Japan, Formosa, and Chōsen before she was stricken in 1935.
Design and description The submarines of the Kaichu III sub-class were a slightly improved version of the preceding Kaichu II subclass, the man difference being an increase in diving depth from .Gray, Randal, ed., Conway′s All the World′s Fighting Ships 1906–1921, Annapolis, Maryland: Naval Institute Press, 1985, , p. 248. They displaced surfaced and submerged. The submarines were long and had a beam of and a draft of .
For surface running, the submarines were powered by two Sulzer Mark II 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, they had a range of at ; submerged, they had a range of at .
The submarines were armed with six torpedo tubes, four internal tubes in the bow and two external tubes mounted on the upper deck, and carried a total of ten Type 44 torpedoes. They were also armed with a single deck gun mounted aft of the conning tower.
Construction and commissioning
Ro-24 was laid down as Submarine No. 42 on 21 April 1919 by the Sasebo Naval Arsenal at Sasebo, Japan. Launched on 8 December 1919, she was completed and commissioned on 30 November 1920 as the first until of the Kaichu III subclass.
Service history
Upon commissioning, Submarine No. 42 was attached to the Sasebo Naval District, to which she remained attached throughout her career. On 15 December 1921, she was assigned to Submarine Division 22 and to the Mako Defense Division at Mako in the Pescadores Islands. On 1 December 1922, Submarine Division 22 was reassigned to the Sasebo Defense Division, and on 1 November 1924, Submarine No. 42 was renamed Ro-24. On 1 December 1924, Submarine Division 22 was reassigned to the Chinkai Defense Division on the southern coast of Chōsen. Submarine Division 22 returned to the Sasebo Defense Division on 1 December 1925, serving in it until 15 November 1934, and thereafter operated directly under the control of the Sasebo Naval District.
Ro-24 was stricken from the Navy list on 1 April 1935. She was hulked on 7 August 1935 and renamed Hulk No. 3107.
Notes
References , History of Pacific War Vol.17 I-Gō Submarines, Gakken (Japan), January 1998, Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces", Gakken (Japan), March 2005, 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 The Maru Special, Japanese Naval Vessels No.135 Japanese Submarines IV, Ushio Shobō (Japan), May 1988, Book code 68344-39