SM UC-21

For other ships with the same name, see German submarine U-21.
March 18, 1917, Imperial German Navy U-boat SM UC-21 sinking American tanker steamer Illinois
History
German Empire
NameUC-21
Ordered29 August 1915[1]
BuilderBlohm & Voss, Hamburg[2]
Yard number271[1]
Launched1 April 1916[1]
Commissioned12 September 1916[1]
FateMissing since September 1917[1]
General characteristics [3]
Class and typeType UC II submarine
Displacement
  • 417 t (410 long tons), surfaced
  • 493 t (485 long tons), submerged
Length
Beam
  • 5.22 m (17 ft 2 in) o/a
  • 3.65 m (12 ft) pressure hull
Draught3.68 m (12 ft 1 in)
Propulsion
Speed
  • 11.6 knots (21.5 km/h; 13.3 mph), surfaced
  • 7.0 knots (13.0 km/h; 8.1 mph), submerged
Range
  • 9,430 nmi (17,460 km; 10,850 mi) at 7 knots (13 km/h; 8.1 mph), surfaced
  • 55 nmi (102 km; 63 mi) at 4 knots (7.4 km/h; 4.6 mph), submerged
Test depth50 m (160 ft)
Complement26
Armament
Notes35-second diving time
Service record[1]
Part of:
  • Flandern Flotilla
  • 14 November 1916 – 30 September 1917
Commanders:
  • Oblt.z.S. Reinhold Saltzwedel[4]
  • 15 September 1916 – 9 June 1917
  • Oblt.z.S. Werner von Zerboni di Sposetti[5]
  • 10 June – 30 September 1917
Operations: 11 patrols
Victories:
  • 95 merchant ships sunk
    (131,844 GRT)
  • 3 auxiliary warships sunk
    (2,219 GRT)
  • 5 merchant ships damaged
    (11,826 GRT)
  • 1 warship damaged
    (778 tons)
  • 1 merchant ship taken as prize
    (148 GRT)

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 29 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 eleven patrols UC-21 was credited with sinking 98 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.[6]

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

  1. ^ a b c d e f g Helgason, Guðmundur. "WWI U-boats: UC 21". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 22 February 2009.
  2. ^ Tarrant 1989, p. 173
  3. ^ Gröner 1991, pp. 31–32.
  4. ^ Helgason, Guðmundur. "WWI U-boat commanders: Reinhold Saltzwedel (Pour le Mérite)". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 14 February 2015.
  5. ^ Helgason, Guðmundur. "WWI U-boat commanders: Werner von Zerboni di Sposetti". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 14 February 2015.
  6. ^ 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.


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