SM ''UC-21'' was a German
Type UC II minelaying submarine
A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...
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''.
["SM" stands for "Seiner Majestät" ( en, His Majesty's) and combined with the ''U'' for ''Unterseeboot'' translates as ''His Majesty's Submarine''.]
In eleven patrols ''UC-21'' was credited with sinking 98 ships, either by torpedo or by
mines laid. They included the British hospital ship , which ''UC-21'' torpedoed in the
English Channel on 17 April 1917, killing 29 already wounded soldiers and 12 crew.
''UC-21'' disappeared after departing
Zeebrugge for the
Bay of Biscay
The Bay of Biscay (), known in Spain as the Gulf of Biscay ( es, Golfo de Vizcaya, eu, Bizkaiko Golkoa), and in France and some border regions as the Gulf of Gascony (french: Golfe de Gascogne, oc, Golf de Gasconha, br, Pleg-mor Gwaskogn), ...
on 13 September 1917.
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]
Design
Like all pre-''UC-25'' Type UC II submarines, ''UC-21'' had a displacement of when at the surface and while submerged. She had a total length of , a beam
Beam may refer to:
Streams of particles or energy
*Light beam, or beam of light, a directional projection of light energy
**Laser beam
*Particle beam, a stream of charged or neutral particles
**Charged particle beam, a spatially localized grou ...
of , and a draught of . The submarine was powered by two six-cylinder four-stroke diesel engines each producing (a total of ), two electric motors producing , and two propeller shafts. She had a dive time of 35 seconds and was capable of operating at a depth of .
The submarine had a maximum surface speed of and a submerged speed of . When submerged, she could operate for at ; when surfaced, she could travel at . ''UC-21'' was fitted with six mine tubes, eighteen UC 200 mines, three torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one Uk L/30 deck gun. Her complement was twenty-six crew members.
Summary of raiding history
Notes
References
Bibliography
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{{DEFAULTSORT:Uc021
Ships built in Hamburg
German Type UC II submarines
U-boats commissioned in 1916
Maritime incidents in 1917
U-boats sunk in 1917
World War I minelayers of Germany
World War I shipwrecks in the Atlantic Ocean
World War I submarines of Germany
1916 ships
Missing U-boats of World War I