U-55 may refer to one of the following German submarines:
Germany, officially the Federal Republic of Germany, is a country in Central and Western Europe, lying between the Baltic and North Seas to the north, and the Alps to the south. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, France to the southwest, and Luxembourg, Belgium and the Netherlands to the west.
- SM U-55, a Type U 51 submarine launched in 1916 and that served in the First World War until surrendered 26 November 1918; in service as Japanese submarine O-3, 1920–21; dismantled at Sasebo, March–June 1921; briefly recommissioned as Auxiliary Vessel No. 2538, 1923
- During the First World War, Germany also had these submarines with similar names:
- SM UB-55, a Type UB III submarine launched in 1917 and sunk on 23 April 1918
- SM UC-55, a Type UC II submarine launched in 1916 and sunk on 29 September 1917
Type UC II minelaying submarines were used by the Imperial German Navy during World War I. They displaced 417 tons, carried guns, 7 torpedoes and up to 18 mines. The ships were double-hulled with improved range and seakeeping compared to the UC I type.
SM UB-55 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the Flanders Flotilla of the German Imperial Navy on 1 July 1917 as SM UB-55.
The Type UB III submarine was a class of U-boat built during World War I by the German Imperial Navy.
SM UC-55 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 12 January 1916, laid down on 25 February 1916, and was launched on 2 August 1916. She was commissioned into the German Imperial Navy on 15 November 1916 as SM UC-55.
- During the First World War, Germany also had these submarines with similar names:
- German submarine U-55 (1939), a Type VIIB submarine that served in the Second World War until sunk 30 January 1940
SM U-55 was one of the six Type U-51 U-boats of the Imperial German Navy during the First World War.
World War I, also known as the First World War or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history. It is also one of the deadliest conflicts in history, with an estimated nine million combatants and seven million civilian deaths as a direct result of the war, while resulting genocides and the 1918 influenza pandemic caused another 50 to 100 million deaths worldwide.
Sasebo is a core city located in Nagasaki Prefecture, Japan. As of 1 October 2016, the city has an estimated population of 251,417 and a population density of 590 persons per km². The total area is 426.47 km2 (165 sq mi).
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