SM UC-21

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Career (German Empire)
Name: UC-21
Ordered: 26 August 1915[1]
Builder: Blohm & Voss, Hamburg[2]
Yard number: 271[1]
Launched: 1 April 1916[1]
Commissioned: 12 September 1916[1]
Fate: disappeared September 1917[1] Found July 2013
General characteristics
Class & type: German Type UC II submarine
Displacement: 417 t (460 short tons), surfaced[2]
493 t (543 short tons), submerged
Length: 161 ft 11 in (49.35 m)[2]
Beam: 17 ft 4 in (5.28 m)[2]
Draft: 12 ft 2 in (4 m)[3]
Propulsion: 2 × propeller shafts
2 × 6-cylinder, 4-stroke diesel engines, 500 bhp (370 kW)[3]
2 × electric motors, 460 shp (340 kW)[3]
Speed: 11.6 knots (21.5 km/h), surfaced[2]
7.0 knots (13.0 km/h), submerged
Endurance: 9,430 nautical miles at 7 knots, surfaced[3]
(17,460 km at 13 km/h)
55 nautical miles at 4 knots, submerged[3]
(102 km at 7.4 km/h)
Test depth: 50 m (160 ft)[3]
Complement: 26[3]
Armament: 6 × 100 cm (39.4 in) mine tubes[3]
18 × UC 200 mines
3 × 50 cm (19.7 in) torpedo tubes (2 bow/external; one stern)
7 × torpedoes
1 × 8.8 cm (3.46 in) KL/30 deck gun[2]
Notes: 35-second diving time[2]

SM UC-21 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) 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 12 September 1916 as SM UC-21.[Note 1]

In 11 patrols UC-21 was credited with sinking 100 ships, either by torpedo or by mines laid. They included the British hospital ship Donegal, which UC-21 torpedoed in the English Channel on 17 April 1917, killing 29 already wounded soldiers and 12 crew.[4]

UC-21 disappeared after departing Zeebrugge for the Bay of Biscay on 13 September 1917.[1]

In July 2013 archaeologists found the wrecks of 44 submarines, including UC-21, off the southern and eastern coasts of Britain, near the county of Suffolk. Most were from the Imperial German Navy from World War I. Der Spiegel reported divers found 41 German U-boats, and three Royal Navy submarines, at depths of up to 50 feet (15 m).[5]

Notes[edit]

  1. ^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot translates as His Majesty's Submarine.

References[edit]

  1. ^ a b c d e f Helgason, Guðmundur (1995–2009). "WWI U-boats: UC-21". U-Boat War in World War I. Uboat.net. Retrieved 22 February 2009. 
  2. ^ a b c d e f g Tarrant 1989, p. 173
  3. ^ a b c d e f g h Gardiner 1985, p. 182
  4. ^ The War on Hospital Ships, With Narratives of Eye-Witnesses and British and German Diplomatic Correspondence (Second and Revised ed.). New York and London: Harper and Brothers. 1918. p. 16. 
  5. ^ "German Subs: Sunken WWI U-Boats a Bonanza for Historians". spiegel.de. Retrieved 21 July 2013. 

Bibliography[edit]