U-51 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-51, the lead ship of the Type U 51 class of submarines; launched in 1915 and that served in the First World War until sunk 14 July 1916
- During the First World War, Germany also had these submarines with similar names:
- SM UB-51, a Type UB III submarine launched in 1917 and surrendered 16 January 1919; broken up at Swansea in 1922
- SM UC-51, a Type UC II submarine launched in 1916 and sunk 17 November 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.
The Type UB III submarine was a class of U-boat built during World War I by the German Imperial Navy.
Swansea, is a coastal city and county, officially known as the City and County of Swansea in Wales. Swansea lies within the historic county boundaries of Glamorgan and the ancient Welsh commote of Gŵyr on the southwest coast. The county area includes Swansea Bay and the Gower Peninsula. Swansea is the second largest city in Wales and the twenty-fifth largest city in the United Kingdom. According to its local council, the City and County of Swansea had a population of 241,300 in 2014. The last official census stated that the city, metropolitan and urban areas combined concluded to be a total of 462,000 in 2011; the second most populous local authority area in Wales after Cardiff.
SM UC-51 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 20 November 1915 and was launched on 5 December 1916. She was commissioned into the German Imperial Navy on 6 January 1917 as SM UC-51. In seven patrols UC-51 was credited with sinking 28 ships, either by torpedo or by mines laid. UC-51 was mined and sunk in the English Channel on 17 November 1917.
- During the First World War, Germany also had these submarines with similar names:
- German submarine U-51 (1938), a Type VIIB submarine that served in the Second World War until sunk on 20 August 1940
SM U-51 was a Type U 51 submarine, one of 329 submarines in the Imperial German Navy in World War I. She engaged in commerce warfare during the First Battle of the Atlantic.
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.
SM UB-51 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the Pola Flotilla of the German Imperial Navy on 26 July 1917 as SM UB-51.
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