Japanese submarine Ro-45

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Empire of Japan
Name: Ro-45
Builder: Mitsubishi Shipbuilding
Commissioned: 11 January 1944
Fate: Disputed (see article)
General characteristics
Class and type: Kaichū type submarine (K6 subclass)
  • 1,133 tonnes (1,115 long tons) surfaced
  • 1,470 tonnes (1,447 long tons) submerged
Length: 80.5 m (264 ft 1 in) overall
Beam: 7 m (23 ft 0 in)
Draft: 4.07 m (13 ft 4 in)
Installed power:
  • 19.75 knots (36.58 km/h; 22.73 mph) surfaced
  • 8 knots (15 km/h; 9.2 mph) submerged
  • 5,000 nmi (9,300 km; 5,800 mi) at 16 knots (30 km/h; 18 mph) surfaced
  • 45 nmi (83 km; 52 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged
Test depth: 80 m (260 ft)
Crew: 61

The Japanese submarine Ro-45 was a Kaichū type submarine of the K6 sub-class built for the Imperial Japanese Navy (IJN) during the 1930s.

Design and description[edit]

The submarines of the K6 sub-class were versions of the preceding K5 sub-class with greater range and diving depth.[1] They displaced 1,133 tonnes (1,115 long tons) surfaced and 1,470 tonnes (1,447 long tons) submerged. The submarines were 80.5 meters (264 ft 1 in) long, had a beam of 7 meters (23 ft 0 in) and a draft of 4.07 meters (13 ft 4 in). They had a diving depth of 80 meters (260 ft).[2]

For surface running, the boats were powered by two 2,100-brake-horsepower (1,566 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600-horsepower (447 kW) electric motor.[3] They could reach 19.75 knots (36.58 km/h; 22.73 mph) on the surface and 8 knots (15 km/h; 9.2 mph) underwater. On the surface, the K6s had a range of 11,000 nautical miles (20,000 km; 13,000 mi) at 12 knots (22 km/h; 14 mph); submerged, they had a range of 45 nmi (83 km; 52 mi) at 5 knots (9.3 km/h; 5.8 mph).[1]

The boats were armed with four internal bow 53.3 cm (21.0 in) torpedo tubes and carried a total of ten torpedoes. They were also armed with a single 76 mm (3 in) anti-aircraft gun and two single 25 mm (1.0 in) AA guns.[1]

Construction and career[edit]

Ro-45 was completed and commissioned at Mitsubishi Shipbuilding on January 11, 1944. It was based in the Maizuru Naval District under the command of Commander Hamazumi Yoshihisa. It was later reassigned to the Sixth Fleet and sent to Truk.

Differing accounts of the submarine's fate exist. Some sources suggest that it was sunk off of the coast of Saipan by the USS Seahorse on 20 April 1944. Other sources, however, indicate that the ship participated in an attack on an American task force near Truk on April 30, 1944. Even these sources differ on the ultimate fate of the ship: some claim it was sunk during the attack, while others say that it was later presumed lost on May 20, 1944.


  1. ^ a b c Carpenter & Dorr, p. 124
  2. ^ Bagnasco, p. 187
  3. ^ Chesneau, p. 203


  • Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-962-6. 
  • Carpenter, Dorr B. & Polmar, Norman (1986). Submarines of the Imperial Japanese Navy 1904–1945. London: Conway Maritime Press. ISBN 0-85177-396-6. 
  • Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 0-85177-146-7. 
  • Hackett, Bob; Kingsepp, Sander (2011). "IJN Submarine RO-45: Tabular Record of Movement". SENSUIKAN! Stories and Battle Histories of the IJN's Submarines. Combinedfleet.com. Retrieved 18 August 2015. 
  • Hackett, Bob; Sander Kingsepp (2003). "Kaichu Type". Sensuikan!. Combinedfleet.com. Retrieved 10 May 2009. 
  • Hashimoto, Mochitsura (1954). Sunk: The Story of the Japanese Submarine Fleet 1942 – 1945. Colegrave, E.H.M. (translator). London: Cassell and Company. ASIN B000QSM3L0.