Japanese submarine Ro-26

Ro-26, originally named Submarine No. 45, was an Imperial Japanese Navy Kaichū-Type submarine, the lead unit of the Kaichū IV subclass. She was in commission from 1923 to 1938 and from 1939 to 1940.

Design and description
The submarines of the Kaichu IV sub-class were an improved version of the preceding Kaichu III subclass, slightly larger, with heavier torpedoes, and with the deck gun mounted forward of the conning tower instead of aft of it. They displaced 750 LT surfaced and 1,080 LT submerged. The submarines were 74.22 m long and had a beam of 6.12 m and a draft of 3.73 m. They had a diving depth of 45.7 m.

For surface running, the submarines were powered by two 1,450 bhp Sulzer Mark II diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600 hp electric motor. They could reach 16 kn on the surface and 8.5 kn underwater. On the surface, they had a range of 6,000 nmi at 10 kn; submerged, they had a range of 85 nmi at 4 kn.

The submarines were armed with four internal bow 533 mm torpedo tubes and carried a total of eight torpedoes. They were also armed with a single 76.2 mm deck gun.

Construction and commissioning
Ro-26 was laid down as Submarine No. 45 on 10 March 1921 by the Sasebo Naval Arsenal at Sasebo, Japan. Launched on 18 October 1921, she was completed and commissioned on 25 January 1923, the lead unit of the Kaichū IV subclass.

Service history
Upon commissioning, Submarine No. 45 was attached to the Kure Naval District, and on 15 December 1923, she was assigned to Submarine Division 14 and to the Kure Defense Division. On 1 April 1924, Submarine Division 14 was reassigned to Submarine Squadron 2 in the 2nd Fleet.

On 16 May 1924 Submarine No. 45′s diving rudders failed while she was conducting a practice attack. Her crew lost control of her, and she sank to the bottom in a vertical position in 170 ft of water. Her crew managed to bring her to the surface, and she suffered no casualties.

On 1 November 1924, Submarine No. 45 was renamed Ro-26. Submarine Division 14 was reassigned to the Kure Naval District on 1 August 1925, and on 18 August 1925 began duty with the Kure Defense Division. This lasted until 1 December 1925, when the division returned to Submarine Squadron 2 in the 2nd Fleet.

On 1 December 1926, Submarine Division 14 was reassigned to the Kure Naval District, in which it remained until 1933. In the years that followed, the division had duty in the Kure Defense Division from 10 December 1928 to 1 December 1930, and Ro-26 underwent a refit in 1932. Ro-26 again served in the Kure Defense Division from 1 October 1932 to 1 February 1933. and was assigned directly to the Kure Naval District from 15 November 1933 to 15 November 1935, then returned to Submarine Division 14. She was decommissioned on 1 December 1938 and placed in Fourth Reserve in the Kure Naval District, then recommissioned on 1 May 1939 and assigned directly to the district.

Ro-26 was decommissioned and stricken from the Navy list on 1 April 1940. She served subsequently as the training hulk Heisan No. 6 at the submarine school at Kure, Japan. She was sold for scrap after World War II; scrapping began at Kanagawa, Japan, in 1947 and was completed in April 1948.