![]() March 18, 1917, Imperial German Navy U-boat SM UC-21 sinking American tanker steamer Illinois
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History | |
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Name | UC-21 |
Ordered | 29 August 1915[1] |
Builder | Blohm & Voss, Hamburg[2] |
Yard number | 271[1] |
Launched | 1 April 1916[1] |
Commissioned | 12 September 1916[1] |
Fate | Missing since September 1917[1] |
General characteristics [3] | |
Class and type | Type UC II submarine |
Displacement | |
Length |
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Beam |
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Draught | 3.68 m (12 ft 1 in) |
Propulsion |
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Speed |
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Range |
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Test depth | 50 m (160 ft) |
Complement | 26 |
Armament |
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Notes | 35-second diving time |
Service record[1] | |
Part of: |
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Commanders: | |
Operations: | 11 patrols |
Victories: |
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
[edit]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 | ![]() |
22 | Sunk |
28 November 1916 | Lady of the Lake | ![]() |
91 | Sunk |
28 November 1916 | Vulcan | ![]() |
27 | Sunk |
28 November 1916 | HMD Pelagia | ![]() |
84 | Sunk |
30 November 1916 | Draupner | ![]() |
1,126 | Sunk |
30 November 1916 | Eggesford | ![]() |
4,414 | Damaged |
30 November 1916 | Therese | ![]() |
165 | Sunk |
1 December 1916 | King Bleddyn | ![]() |
4,387 | Sunk |
2 December 1916 | Demetrios Inglesis | ![]() |
2,088 | Sunk |
2 December 1916 | Robinson | ![]() |
186 | Sunk |
2 December 1916 | Uribitarte | ![]() |
1,756 | Sunk |
3 December 1916 | Aiglon | ![]() |
280 | Sunk |
3 December 1916 | Louise | ![]() |
155 | Sunk |
3 December 1916 | Verdun | ![]() |
184 | Sunk |
4 December 1916 | Pallas | ![]() |
1,202 | Sunk |
5 December 1916 | Nexos | ![]() |
1,013 | Sunk |
6 December 1916 | Gerona | ![]() |
1,328 | Sunk |
7 December 1916 | Avristan | ![]() |
3,818 | Sunk |
8 December 1916 | HMT Dagon | ![]() |
250 | Sunk |
8 December 1916 | Falk | ![]() |
1,379 | Sunk |
8 December 1916 | Marjolaine | ![]() |
163 | Sunk |
8 December 1916 | Modum | ![]() |
2,937 | Sunk |
17 December 1916 | Margaret | ![]() |
54 | Sunk |
18 January 1917 | HMS Ferret | ![]() |
778 | Damaged |
19 January 1917 | Joseph Rosalie | ![]() |
138 | Sunk |
19 January 1917 | Marietta Di Giorgio | ![]() |
988 | Sunk |
19 January 1917 | Tremeadow | ![]() |
3,653 | Sunk |
20 January 1917 | Kisagata Maru No. 3 | ![]() |
2,588 | Sunk |
20 January 1917 | Jotunfjell | ![]() |
2,492 | Damaged |
21 January 1917 | Victoire | ![]() |
290 | Damaged |
21 January 1917 | Leontine | ![]() |
124 | Sunk |
21 January 1917 | Saint Pierre | ![]() |
127 | Sunk |
22 January 1917 | Bearnais | ![]() |
301 | Sunk |
22 January 1917 | Precurseur | ![]() |
364 | Sunk |
22 January 1917 | Steinmachos | ![]() |
1,175 | Sunk |
24 January 1917 | Dan | ![]() |
1,869 | Sunk |
24 January 1917 | Gladiateur | ![]() |
23 | Sunk |
24 January 1917 | Loire III | ![]() |
27 | Sunk |
24 January 1917 | Marie 3 | ![]() |
25 | Sunk |
24 January 1917 | Quebec | ![]() |
3,346 | Sunk |
24 January 1917 | Vega | ![]() |
195 | Sunk |
25 January 1917 | Myrdal | ![]() |
2,631 | Sunk |
1 February 1917 | Sainte Helene | ![]() |
2,128 | Sunk |
10 February 1917 | Beechtree | ![]() |
1,277 | Sunk |
11 February 1917 | Dernes | ![]() |
738 | Sunk |
12 February 1917 | Nordcap | ![]() |
332 | Sunk |
13 February 1917 | Progreso | ![]() |
1,620 | Sunk |
14 February 1917 | Longscar | ![]() |
2,777 | Sunk |
14 February 1917 | Mar Adriatico | ![]() |
2,410 | Sunk |
15 February 1917 | Aline | ![]() |
30 | Sunk |
15 February 1917 | Marion Dawson | ![]() |
2,300 | Sunk |
16 February 1917 | Niobe | ![]() |
1,319 | Sunk |
16 February 1917 | Pollcrea | ![]() |
1,209 | Damaged |
17 February 1917 | Cabo | ![]() |
1,254 | Sunk |
17 February 1917 | Silene | ![]() |
171 | Sunk |
18 February 1917 | Triumph | ![]() |
52 | Sunk |
19 February 1917 | Rutenfjell | ![]() |
1,844 | Sunk |
10 March 1917 | Asbjørn | ![]() |
3,459 | Sunk |
12 March 1917 | Alice Charles | ![]() |
41 | Sunk |
12 March 1917 | Arethuse | ![]() |
40 | Sunk |
13 March 1917 | Girda | ![]() |
1,824 | Sunk |
13 March 1917 | Vivina | ![]() |
3,034 | Sunk |
14 March 1917 | Blaamanden | ![]() |
954 | Sunk |
14 March 1917 | La Marne | ![]() |
133 | Sunk |
15 March 1917 | Eugene Robert | ![]() |
98 | Sunk |
15 March 1917 | Fleur D’Esperance | ![]() |
24 | Sunk |
15 March 1917 | Frimaire | ![]() |
1,778 | Sunk |
15 March 1917 | Petit Jean | ![]() |
21 | Sunk |
16 March 1917 | Anais | ![]() |
130 | Sunk |
16 March 1917 | Madeleine Davoust | ![]() |
148 | Sunk |
16 March 1917 | Ronald | ![]() |
3,021 | Sunk |
18 March 1917 | Illinois | ![]() |
5,225 | Sunk |
17 April 1917 | HMHS Donegal | ![]() |
1,885 | Sunk |
19 April 1917 | Cilurnum | ![]() |
3,126 | Sunk |
20 April 1917 | Georgios | ![]() |
3,124 | Sunk |
21 April 1917 | Emile Et Charlotte | ![]() |
41 | Sunk |
21 April 1917 | Ville De Dieppe | ![]() |
1,254 | Sunk |
22 April 1917 | Capenor | ![]() |
2,536 | Sunk |
22 April 1917 | Percy Birdsall | ![]() |
1,127 | Sunk |
22 April 1917 | Valerie | ![]() |
2,140 | Sunk |
24 April 1917 | Barnton | ![]() |
1,858 | Sunk |
25 April 1917 | Baigorry | ![]() |
2,161 | Sunk |
26 April 1917 | Boy Denis | ![]() |
41 | Sunk |
22 May 1917 | Jeune Albert | ![]() |
25 | Sunk |
23 May 1917 | Harwood Palmer | ![]() |
2,885 | Sunk |
23 May 1917 | Lesto | ![]() |
1,940 | Sunk |
26 May 1917 | Aristides | ![]() |
2,179 | Sunk |
26 May 1917 | Norhaug | ![]() |
1,245 | Sunk |
27 May 1917 | Efstathios | ![]() |
3,847 | Sunk |
28 May 1917 | Hiram | ![]() |
598 | Sunk |
28 May 1917 | Urna | ![]() |
2,686 | Sunk |
28 May 1917 | Waldemar | ![]() |
1,267 | Sunk |
30 May 1917 | Sørland | ![]() |
2,472 | Sunk |
2 June 1917 | Tonawanda | ![]() |
3,421 | Damaged |
7 June 1917 | Hafnia | ![]() |
1,619 | Sunk |
29 June 1917 | Lauwerzee | ![]() |
47 | Sunk |
4 July 1917 | Bestevaer | ![]() |
1,044 | Sunk |
4 July 1917 | Roelfina | ![]() |
148 | Captured as prize |
11 July 1917 | Coquimbo | ![]() |
1,759 | Sunk |
15 August 1917 | Phoebe | ![]() |
3,956 | Sunk |
17 August 1917 | Pontoporos | ![]() |
4,049 | Sunk |
19 August 1917 | Therese & Marie | ![]() |
1,615 | Sunk |
31 August 1917 | Marques De Mudela | ![]() |
1,930 | Sunk |
16 September 1917 | Ann J. Trainer | ![]() |
426 | Sunk |
23 September 1917 | St. Dunstan | ![]() |
730 | Sunk |
Notes
[edit]- ^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot translates as His Majesty's Submarine.
- ^ Merchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement.
References
[edit]- ^ 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.
- ^ Tarrant 1989, p. 173
- ^ a b c Gröner 1991, pp. 31–32.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.