Japanese submarine Ro-32

Ro-32, originally named Submarine No. 71, was an Imperial Japanese Navy Kaichu-Type submarine of the Kaichu V (Toku Chu) subclass. She was in commission from 1924 to 1938, seeing service in the waters of Formosa and Japan, then served as a stationary training hulk during World War II.

Design and description
The submarines of the Kaichu V sub-class were designed for anti-shipping operations and carried more fuel and had greater range and a heavier gun armament than preceding Kaichu-type submarines. They displaced 852 LT surfaced and 1,020 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 600 bhp Sulzer diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600 hp electric motor. They could reach 13 kn on the surface and 8.5 kn underwater. On the surface, they had a range of 9,000 nmi — although the Imperial Japanese Navy officially announced it as 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 120 mm deck gun and one 6.5 mm machine gun.

Construction and commissioning
Ro-32 was laid down as Submarine No. 71 on 24 October 1921 by Kawasaki at Kobe, Japan. Launched on 19 March 1923, she was completed and commissioned on 31 May 1924.

Service history
Upon commissioning, Submarine No. 71 was attached to the Sasebo Naval District, to which she remained attached throughout her active career. On 15 June 1924, she was assigned to both Submarine Division 25 — in which she spent her active career — and the Mako Defense Division headquartered at Mako in the Pescadores Islands. She was renamed Ro-32 on 1 November 1924. On 1 December 1926, she was reassigned to the Sasebo Defense Division, headquartered at Sasebo, Japan. Her service in the Sasebo Defense Division ended on 15 November 1934, after which she served as a unit of Submarine Division 25 in the Sasebo Naval District.

Ro-32 was decommissioned and placed in the Fourth Reserve on 15 December 1938. The Japanese struck her from the Navy list on 1 April 1942, and that day she became a stationary training hulk at the submarine school at Ōtake, Japan. She was scrapped ca. August 1945.

During World War II, the United States Coast Guard cutter USCGC McLane (WSC-146), the Coast Guard-manned United States Navy patrol vessel USS YP-251, and a Royal Canadian Air Force Bristol Bolingbroke maritime patrol aircraft of No. 115 Squadron shared credit for the sinking of a submarine in the Pacific Ocean off Southeast Alaska at 55.33333°N, -134.66667°W on 9 July 1942, and in 1947 the Joint Army-Navy Assessment Committee identified the sunken submarine as Ro-32. In 1967, the U.S. Navy retracted that finding after determining that Ro-32 had been inactive in Japan at the time of the sinking and had remained afloat through the end of World War II.