Military Wiki
Japanese submarine I-51
HIJMS I51-1924.jpg
I-51 in 1924
Career (Japan)
Name: I-51
Ordered: 1918 Fiscal Year
Builder: Kure Naval Arsenal
Laid down: 6 April 1921, as S22
Launched: 29 November 1921
Completed: 20 June 1924, as Submarine 44
Commissioned: 1 November 1924, as I-51
Struck: 1 April 1940
Homeport: Kure Naval District
Fate: Scrapped 1940
General characteristics
Class & type: Kaidai-class submarine (Type I)
  • 1,833 long tons (1,862 t) surfaced
  • 2,602 long tons (2,644 t) submerged
Length: 99.44 m (326 ft 3 in)
Beam: 8.81 m (28 ft 11 in)
Draught: 4.6 m (15 ft 1 in)
  • 4 × Sulzer diesel engines,5,200 hp (3.9 MW)
  • 4 x Electric motors, 2,000 hp (1.5 MW)
  • 18.5 knots (34.3 km/h; 21.3 mph) (surfaced)
  • 8.4 kn (15.6 km/h; 9.7 mph) (submerged)
  • Range:
  • 20,000 nmi (37,000 km) @ 10 kn (19 km/h; 12 mph) (surfaced)
  • 100 nmi (190 km) @ 4 kn (7.4 km/h; 4.6 mph) (submerged)
  • Endurance: 47.5 m (156 ft)
    Complement: 70 officers and men

    Japanese submarine I-51 (伊号第五一潜水艦 I-gō Dai Gojū-ichi sensuikan?) was the lead vessel and prototype of the Kaidai-class submarines of the Imperial Japanese Navy, which served in World War II.


    Following World War I, the Imperial Japanese Navy General Staff began to re-consider submarine warfare as an element of fleet strategy. Before the war, the Japanese Navy regarded submarines as useful only for short-range coastal point defense.[1] However, based on the success of the Imperial German Navy in deployment of long-range cruiser-submarines for commerce raiding Japanese strategists came to realize possibilities for using the weapon for long range reconnaissance, and in a war of attrition against an enemy fleet approaching Japan.[1] Procurement for a large, long-range Japanese submarine was authorized in fiscal 1918 under the Eight-six fleet program, under the designation S22.


    Project S22 was based on the latest Royal Navy design, the British K class submarine. Japanese ties to Great Britain via the Anglo-Japanese Alliance were still strong. Project S22 was laid down at Kure Naval Arsenal on 6 April 1921, launched on 29 November 1921 and completed on 20 June 1924.[2]

    During construction, the vessel was renamed Submarine No.44 (第四四号潜水艦 Dai-Yonjūyon-go sensuikan?), however, on commissioning into the Imperial Japanese Navy, her name was formally registered as I-51.

    With a displacement of 1390 tons, I-51 was the largest submarine built in Japan to date. In order to attain a design speed of 23 knots on the surface, and 15 knots submerged, the design required four diesel engines, driving four screws. To accommodate these engines, a double hull design was used, with hulls joined side-by-side forming a sideways figure "8".

    As completed, I-51 achieved only 18.4 knots surfaced and 8.4 knots submerged during trials, but had an unrefueled range of 20,000 nautical miles, which was considered remarkable for the time.[1]

    Operational history

    I-51, despite her various technical achievements, as not regarded as a successful design, largely through problems with her Sulzer diesel engines. The vessel was never assigned to fleet service, but was retained at Kure Naval Arsenal for crew training and as a test bed for various submarine technologies.

    In 1931, I-51 was fitted with an aircraft hanger housing a Yokosuka Ro-go Ko-gata floatplane, which could be raised and lowered into the water by a crane. In 1933, this was modified with the addition of an aircraft catapult, making I-51 the forerunner of the Japanese submarine aircraft carriers of World War II.

    In 1932, two of her engines and associated shafts were removed, as was her main gun.[2]

    I-51 was removed from the navy list on 1 April 1940 and was scrapped in 1941.


    • Boyd, Carl (2002). The Japanese Submarine Force in World War II. Annapolis, MD: Naval Institute Press. ISBN 1557500150. 
    • Peattie, Mark R. (1997). Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941. Annapolis, MD: Naval Institute Press. ISBN 0-87021-192-7. 
    • Jentsura, Hansgeorg (1976). Warships of the Imperial Japanese Navy, 1869-1945. Annapolis, MD: Naval Institute Press. ISBN 0-87021-893-X. 
    • Stille, Mark (2007). Imperial Japanese Navy Submarines 1941-45. Osprey. ISBN 1846030900. 

    External links


    1. 1.0 1.1 1.2 Peatty, Kaigun, p.114, 212-214
    2. 2.0 2.1 Jentsura, Warships of the Imperial Japanese Navy, 1869-1945, p.190

    This page uses Creative Commons Licensed content from Wikipedia (view authors).