Name UB-21 Yard number 251 Commissioned 20 February 1916 Construction started 1915 Draft 3.7 m | Ordered 30 April 1915 Completed 18 February 1916 Fate sunk 1920 Launched 26 September 1915 Builder Blohm + Voss | |
SM UB-21 was a German Type UB II submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) 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 20 February 1916 as SM UB-21. The submarine sank 33 ships in 26 patrols for a total of 36,764 gross register tons (GRT). Surrendered to Britain in accordance with the requirements of the Armistice with Germany, UB-21 sank in 1920 in the eastern Solent while en route to be broken up [1].
Design
A German Type UB II submarine, UB-21 had a displacement of 263 tonnes (259 long tons) when at the surface and 292 tonnes (287 long tons) while submerged. She had a total length of 36.13 m (118 ft 6 in), a beam of 4.36 m (14 ft 4 in), and a draught of 3.70 m (12 ft 2 in). The submarine was powered by two Körting six-cylinder, four-stroke diesel engines each producing a total 280 metric horsepower (280 shp; 210 kW), a Siemens-Schuckert electric motor producing 206 kilowatts (276 shp; 280 PS), and one propeller shaft. She was capable of operating at depths of up to 50 metres (160 ft).
The submarine had a maximum surface speed of 9.15 knots (16.95 km/h; 10.53 mph) and a maximum submerged speed of 5.81 knots (10.76 km/h; 6.69 mph). When submerged, she could operate for 45 nautical miles (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 6,650 nautical miles (12,320 km; 7,650 mi) at 5 knots (9.3 km/h; 5.8 mph). UB-21 was fitted with two 50 centimetres (20 in) torpedo tubes, four torpedoes, and one 5 centimetres (2.0 in) SK L/40 deck machine gun. She had a complement of twenty-one crew members and two officers and a 45-second dive time.