# SM UC-23

SM UC-23 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 29 February 1916. She was commissioned into the German Imperial Navy on 17 July 1916 as SM UC-23. In 17 patrols UC-23 was credited with sinking 46 ships, either by torpedo or by mines laid. UC-23 was surrendered at Sevastopol on 25 November 1918 and broken up at Bizerta in August 1921.

## Design

Like all pre-UC-25 Type UC II submarines, UC-23 had a displacement of 417 tonnes (410 long tons) when at the surface and 493 tonnes (485 long tons) while submerged. She had a length overall 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).
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-23 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.

## Summary of raiding history

| Date | Name | Nationality | Tonnage | Fate |
| 29 November 1916 | Minnewaska | United Kingdom | 14,317 | Sunk |
| 31 December 1916 | Venus | French Navy | 281 | Sunk |
| 21 February 1917 | HMS Princess Alberta | Royal Navy | 1,586 | Sunk |
| 10 June 1917 | Kleopatra | Greece | 160 | Sunk |
| 13 June 1917 | Aghios Nicolaos | Greece | 120 | Sunk |
| 14 June 1917 | New Zealand Transport | United Kingdom | 4,481 | Sunk |
| 18 June 1917 | Pannomitis | Greece | 11 | Sunk |
| 18 June 1917 | Xiphias | Greece | 483 | Sunk |
| 19 June 1917 | Jakobus | Greece | 304 | Sunk |
| 19 June 1917 | Maria | Greece | 35 | Sunk |
| 19 June 1917 | Raxiarchos | Greece | 30 | Sunk |
| 2 August 1917 | HMS Ermine | Royal Navy | 1,777 | Sunk |
| 6 September 1917 | HMT Helgian | Royal Navy | 220 | Sunk |
| 7 September 1917 | HMT By George | Royal Navy | 225 | Sunk |
| 21 September 1917 | Santo Nicola | Kingdom of Italy | 159 | Sunk |
| 21 September 1917 | Spiridon | Greece | 128 | Sunk |
| 23 September 1917 | Nicolaos | Greece | 104 | Sunk |
| 19 January 1918 | Trocas | United Kingdom | 4,129 | Sunk |
| 22 January 1918 | Evangelistria | Greece | 21 | Sunk |
| 23 January 1918 | Birkhall | United Kingdom | 4,541 | Sunk |
| 24 January 1918 | Aghia Arene | Greece | 16 | Sunk |
| 24 January 1918 | Aghios Johannes | Greece | 14 | Sunk |
| 20 February 1918 | Hagios Nicolaos | Greece | 18 | Sunk |
| 20 February 1918 | Maria Archis | Greece | 13 | Sunk |
| 20 February 1918 | Taxi Arches | Greece | 3 | Sunk |
| 23 February 1918 | Aspasia | Greece | 105 | Sunk |
| 28 February 1918 | Hagios Triast | Greece | 22 | Sunk |
| 11 April 1918 | Trud | Imperial Russian Navy | 610 | Captured as prize |
| 14 April 1918 | Unidentified lighter | Russian Empire | 100 | Sunk |
| 14 April 1918 | Kazak | Imperial Russian Navy | 622 | Captured as prize |
| 14 April 1918 | Olga | Imperial Russian Navy | 327 | Captured as prize |
| 15 April 1918 | Rostov | Imperial Russian Navy | 1,280 | Sunk |
| 3 October 1918 | Blasios | Greece | 181 | Sunk |
| 3 October 1918 | Evangelistria | Greece | 35 | Damaged |
| 5 October 1918 | Hagios Marcos | Greece | 45 | Sunk |
| 5 October 1918 | Maria | Spain | 2,159 | Sunk |
| 5 October 1918 | Marigo | Greece | 48 | Sunk |
| 5 October 1918 | Reventazon | United Kingdom | 4,050 | Sunk |
| 13 October 1918 | Aghion Spiridon | Greece | 21 | Sunk |
| 13 October 1918 | Aghios Georgios | Greece | 130 | Sunk |
| 13 October 1918 | Biolleta | Greece | 99 | Sunk |
| 13 October 1918 | Evangelistria | Greece | 41 | Sunk |
| 13 October 1918 | Evangelistrios | Greece | 121 | Sunk |
| 13 October 1918 | Glaros | Greece | 43 | Sunk |
| 13 October 1918 | Iphigenia | Greece | 75 | Sunk |
| 13 October 1918 | Panaghia | Greece | 26 | Sunk |
| 13 October 1918 | Urania | Greece | 23 | Sunk |
| 15 October 1918 | Evangelistria | Greece | 24 | Sunk |
| 15 October 1918 | Georgios | Greece | 29 | Sunk |
| 15 October 1918 | Maria | Greece | 43 | Sunk |