U-20 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-20 (Germany), was a Type U 19 submarine launched in 1912 and that served in the First World War until grounded on 4 November 1916; notable for sinking RMS Lusitania
- During the First World War, Germany also had these submarines with similar names:
- SM UB-20, a Type UB II submarine launched in 1915 and sunk 28 July 1917
- SM UC-20, a Type UC II submarine launched in 1916 and surrendered on 16 January 1919
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-20 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 26 September 1915. She was commissioned into the German Imperial Navy on 10 February 1916 as SM UB-20. The submarine sank 13 ships in 15 patrols for a total of 10,230 gross register tons (GRT). UB-20 was mined and sunk on 28 July 1917 at 51°25′N3°20′W. Thirteen crew members died in the event.
The UB II type submarine was a class of U-boat built during World War I by the German Imperial Navy. They were enlarged from the preceding type UB I and were more effective vessels. The boats were a single hull design with a 50-metre maximum diving depth and a 30-45 second diving time. In 1915 and 1916, 30 were built at two different shipyards.
SM UC-20 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 26 August 1915 and was launched on 1 April 1916. She was commissioned into the German Imperial Navy on 7 September 1916 as SM UC-20. In 13 patrols UC-20 was credited with sinking 21 ships, either by torpedo or by mines laid. UC-20 was surrendered on 16 January 1919 and broken up at Preston in 1919–20.
- During the First World War, Germany also had these submarines with similar names:
- German submarine U-20 (1936), a Type IIB submarine that served in the Second World War and was scuttled on 10 September 1944
- German submarine U-20 (S199), a Type 206 submarine of the Bundesmarine that was launched in 1974 and scrapped in 1996 and sold to Indonesia
SM U-20 was a German Type U 19 U-boat built for service in the Imperial German Navy. She was launched on 18 December 1912, and commissioned on 5 August 1913. During World War I, she took part in operations around the British Isles. U-20 became infamous following her sinking of the British ocean liner RMS Lusitania on 7 May 1915, an act that dramatically reshaped the course of World War I.
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.
RMS Lusitania was a British ocean liner and briefly the world's largest passenger ship. The ship was sunk on 7 May 1915 by a German U-boat 11 mi (18 km) off the southern coast of Ireland. The sinking presaged the United States declaration of war on Germany (1917).
U-20 or U-XX may also refer to:
- SM U-20 (Austria-Hungary), lead boat of the U-20-class submarines for the Austro-Hungarian Navy
SM U-20 or U-XX was the lead boat of the U-20 class of submarines or U-boats built for and operated by the Austro-Hungarian Navy during the First World War. The design for U-20 was based on submarines of the Royal Danish Navy's Havmanden class, and was largely obsolete by the beginning of the war.
The U-20 class was a class of four submarines or U-boats built for and operated by the Austro-Hungarian Navy during World War I. The class is sometimes referred to as the Havmanden class because it was based upon the design of the Royal Danish Navy's 1911 Havmanden-class submarines, three of which were built in Fiume.
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