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SM UC-21

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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 & 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]

Design

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Like all pre-UC-25 Type UC II submarines, UC-21 had a displacement of 417 tonnes (410 long tons) when at the surface and 493 tonnes (485 long tons) while submerged. She had a total length of 49.35 m (161 ft 11 in), a beam of 5.22 m (17 ft 2 in), and a draught of 3.65 m (12 ft). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 250 metric horsepower (180 kW; 250 shp) (a total of 500 metric horsepower (370 kW; 490 shp)), two electric motors producing 460 metric horsepower (340 kW; 450 shp), and two propeller shafts. She had a dive time of 35 seconds and was capable of operating at a depth of 50 metres (160 ft).[3]

The submarine had a maximum surface speed of 11.6 knots (21.5 km/h; 13.3 mph) and a submerged speed of 7 knots (13 km/h; 8.1 mph). When submerged, she could operate for 55 nautical miles (102 km; 63 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 9,430 nautical miles (17,460 km; 10,850 mi) at 7 knots (13 km/h; 8.1 mph). UC-21 was fitted with six 100 centimetres (39 in) mine tubes, eighteen UC 200 mines, three 50 centimetres (20 in) torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 8.8 cm (3.5 in) Uk L/30 deck gun. Her complement was twenty-six crew members.[3]

Summary of raiding history

[edit]
Date Name Nationality Tonnage[Note 2] Fate[7]
28 November 1916 Clematis United Kingdom 22 Sunk
28 November 1916 Lady of the Lake United Kingdom 91 Sunk
28 November 1916 Vulcan United Kingdom 27 Sunk
28 November 1916 HMD Pelagia  Royal Navy 84 Sunk
30 November 1916 Draupner Norway 1,126 Sunk
30 November 1916 Eggesford United Kingdom 4,414 Damaged
30 November 1916 Therese France 165 Sunk
1 December 1916 King Bleddyn United Kingdom 4,387 Sunk
2 December 1916 Demetrios Inglesis Greece 2,088 Sunk
2 December 1916 Robinson France 186 Sunk
2 December 1916 Uribitarte Spain 1,756 Sunk
3 December 1916 Aiglon France 280 Sunk
3 December 1916 Louise France 155 Sunk
3 December 1916 Verdun France 184 Sunk
4 December 1916 Pallas Russian Empire 1,202 Sunk
5 December 1916 Nexos Denmark 1,013 Sunk
6 December 1916 Gerona Spain 1,328 Sunk
7 December 1916 Avristan United Kingdom 3,818 Sunk
8 December 1916 HMT Dagon  Royal Navy 250 Sunk
8 December 1916 Falk Norway 1,379 Sunk
8 December 1916 Marjolaine France 163 Sunk
8 December 1916 Modum Norway 2,937 Sunk
17 December 1916 Margaret United Kingdom 54 Sunk
18 January 1917 HMS Ferret  Royal Navy 778 Damaged
19 January 1917 Joseph Rosalie France 138 Sunk
19 January 1917 Marietta Di Giorgio Norway 988 Sunk
19 January 1917 Tremeadow United Kingdom 3,653 Sunk
20 January 1917 Kisagata Maru No. 3 Japan 2,588 Sunk
20 January 1917 Jotunfjell Norway 2,492 Damaged
21 January 1917 Victoire France 290 Damaged
21 January 1917 Leontine France 124 Sunk
21 January 1917 Saint Pierre France 127 Sunk
22 January 1917 Bearnais France 301 Sunk
22 January 1917 Precurseur France 364 Sunk
22 January 1917 Steinmachos Greece 1,175 Sunk
24 January 1917 Dan Denmark 1,869 Sunk
24 January 1917 Gladiateur France 23 Sunk
24 January 1917 Loire III France 27 Sunk
24 January 1917 Marie 3 France 25 Sunk
24 January 1917 Quebec France 3,346 Sunk
24 January 1917 Vega Denmark 195 Sunk
25 January 1917 Myrdal Norway 2,631 Sunk
1 February 1917 Sainte Helene France 2,128 Sunk
10 February 1917 Beechtree United Kingdom 1,277 Sunk
11 February 1917 Dernes Norway 738 Sunk
12 February 1917 Nordcap Norway 332 Sunk
13 February 1917 Progreso Norway 1,620 Sunk
14 February 1917 Longscar United Kingdom 2,777 Sunk
14 February 1917 Mar Adriatico Spain 2,410 Sunk
15 February 1917 Aline France 30 Sunk
15 February 1917 Marion Dawson United Kingdom 2,300 Sunk
16 February 1917 Niobe France 1,319 Sunk
16 February 1917 Pollcrea United Kingdom 1,209 Damaged
17 February 1917 Cabo Norway 1,254 Sunk
17 February 1917 Silene France 171 Sunk
18 February 1917 Triumph United Kingdom 52 Sunk
19 February 1917 Rutenfjell Norway 1,844 Sunk
10 March 1917 Asbjørn Norway 3,459 Sunk
12 March 1917 Alice Charles France 41 Sunk
12 March 1917 Arethuse France 40 Sunk
13 March 1917 Girda Norway 1,824 Sunk
13 March 1917 Vivina Spain 3,034 Sunk
14 March 1917 Blaamanden Norway 954 Sunk
14 March 1917 La Marne France 133 Sunk
15 March 1917 Eugene Robert France 98 Sunk
15 March 1917 Fleur D’Esperance France 24 Sunk
15 March 1917 Frimaire United Kingdom 1,778 Sunk
15 March 1917 Petit Jean France 21 Sunk
16 March 1917 Anais France 130 Sunk
16 March 1917 Madeleine Davoust France 148 Sunk
16 March 1917 Ronald Norway 3,021 Sunk
18 March 1917 Illinois United States 5,225 Sunk
17 April 1917 HMHS Donegal  Royal Navy 1,885 Sunk
19 April 1917 Cilurnum United Kingdom 3,126 Sunk
20 April 1917 Georgios Greece 3,124 Sunk
21 April 1917 Emile Et Charlotte France 41 Sunk
21 April 1917 Ville De Dieppe Norway 1,254 Sunk
22 April 1917 Capenor United Kingdom 2,536 Sunk
22 April 1917 Percy Birdsall United States 1,127 Sunk
22 April 1917 Valerie Norway 2,140 Sunk
24 April 1917 Barnton United Kingdom 1,858 Sunk
25 April 1917 Baigorry France 2,161 Sunk
26 April 1917 Boy Denis United Kingdom 41 Sunk
22 May 1917 Jeune Albert France 25 Sunk
23 May 1917 Harwood Palmer United States 2,885 Sunk
23 May 1917 Lesto United Kingdom 1,940 Sunk
26 May 1917 Aristides Greece 2,179 Sunk
26 May 1917 Norhaug Norway 1,245 Sunk
27 May 1917 Efstathios Greece 3,847 Sunk
28 May 1917 Hiram Norway 598 Sunk
28 May 1917 Urna Norway 2,686 Sunk
28 May 1917 Waldemar Norway 1,267 Sunk
30 May 1917 Sørland Norway 2,472 Sunk
2 June 1917 Tonawanda United Kingdom 3,421 Damaged
7 June 1917 Hafnia Denmark 1,619 Sunk
29 June 1917 Lauwerzee Netherlands 47 Sunk
4 July 1917 Bestevaer Netherlands 1,044 Sunk
4 July 1917 Roelfina Netherlands 148 Captured as prize
11 July 1917 Coquimbo France 1,759 Sunk
15 August 1917 Phoebe France 3,956 Sunk
17 August 1917 Pontoporos Greece 4,049 Sunk
19 August 1917 Therese & Marie France 1,615 Sunk
31 August 1917 Marques De Mudela Spain 1,930 Sunk
16 September 1917 Ann J. Trainer United States 426 Sunk
23 September 1917 St. Dunstan United Kingdom 730 Sunk

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.
  2. ^ Merchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement.

References

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  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. ^ a b c 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.
  7. ^ Helgason, Guðmundur. "Ships hit by UC 21". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 12 December 2014.

Bibliography

[edit]
  • Bendert, Harald (2001). Die UC-Boote der Kaiserlichen Marine 1914-1918. Minenkrieg mit U-Booten (in German). Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0758-7.
  • Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
  • Gardiner, Robert, ed. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, MD: Naval Institute Press. ISBN 978-0-87021-907-8. OCLC 12119866.
  • Tarrant, V. E. (1989). The U-Boat Offensive: 1914–1945. Annapolis, MD: Naval Institute Press. ISBN 978-0-87021-764-7. OCLC 20338385.

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