SM U-21 (Austria-Hungary)
SM U-21 loads a torpedo during World War I. | |
| History | |
|---|---|
| Austria-Hungary | |
| Name | SM U-21 |
| Ordered | 27 March 1915 |
| Builder | Pola Navy Yard, Pola |
| Laid down | Mid 1915 |
| Launched | 15 August 1916 |
| Commissioned | 15 August 1917 |
| Fate | Ceded to Italy, scrapped 1920 |
| Service record | |
| Commanders: |
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| Victories: | None |
| General characteristics | |
| Type | U-20-class submarine |
| Displacement |
|
| Length | 127 ft 2 in (38.76 m) |
| Beam | 13 ft (4.0 m) |
| Draft | 9 ft (2.7 m) |
| Propulsion |
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| Speed |
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| Range |
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| Complement | 18 |
| Armament |
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SM U-21 or U-XXI was a U-20-class submarine or U-boat built for and operated by the Austro-Hungarian Navy (German: Kaiserliche und Königliche Kriegsmarine or K.u.K. Kriegsmarine) during the First World War. The design for U-21 was based on submarines of the Royal Danish Navy's Havmanden class (three of which had been built in Austria-Hungary), and was largely obsolete by the beginning of the war.
U-21 was just over 127 feet (39 m) long and was armed with two bow torpedo tubes, a deck gun, and a machine gun. Construction on U-21 began in mid 1915 and the boat was launched in September 1916. After suffering damage during a diving trial in January 1917, U-21 underwent seven months of repairs before her commissioning in August 1917.
The U-boat conducted patrols off the Albanian coast in October 1917, but experienced the failure of the seal on her main hatch. The repairs kept the boat out of action until June 1918. But in July a piston in her diesel engine broke, knocking the submarine out of the rest of the war. At the end of World War I, U-21 was ceded to Italy as a war reparation and scrapped in 1920. U-21 had no wartime successes.