# SM UC-66

SM UC-66 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 12 January 1916 and was launched on 15 July 1916. She was commissioned into the German Imperial Navy on 14 November 1916 as SM UC-66. In five patrols UC-66 was credited with sinking 32 ships, either by torpedo or by mines laid. UC-66 was sunk by HM seaplane No. 8656, a Curtiss Model H-12, off the Isles of Scilly on 27 May 1917. The wreck was found by divers in 2009. This is a notable early aircraft success against a U-boat.

## Design

A Type UC II submarine, UC-66 had a displacement of 427 tonnes (420 long tons) when at the surface and 508 tonnes (500 long tons) while submerged. She had a length overall of 50.35 m (165 ft 2 in), a beam of 5.22 m (17 ft 2 in), and a draught of 3.64 m (11 ft 11 in). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 300 metric horsepower (220 kW; 300 shp) (a total of 600 metric horsepower (440 kW; 590 shp)), two electric motors producing 620 metric horsepower (460 kW; 610 shp), and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of 50 metres (160 ft).
The submarine had a maximum surface speed of 12 knots (22 km/h; 14 mph) and a submerged speed of 7.4 knots (13.7 km/h; 8.5 mph). When submerged, she could operate for 52 nautical miles (96 km; 60 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 10,420 nautical miles (19,300 km; 11,990 mi) at 7 knots (13 km/h; 8.1 mph). UC-66 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 |
| 11 February 1917 | Ada | United Kingdom | 187 | Sunk |
| 11 February 1917 | Vasilissa Olga | Greece | 1,400 | Sunk |
| 11 February 1917 | Woodfield | United Kingdom | 4,300 | Damaged |
| 12 February 1917 | Afric | United Kingdom | 11,999 | Sunk |
| 12 February 1917 | Lucent | United Kingdom | 1,409 | Sunk |
| 15 February 1917 | Alma Jeanne | France | 33 | Sunk |
| 15 February 1917 | Argos | France | 26 | Sunk |
| 15 February 1917 | Desire Louise | France | 31 | Sunk |
| 17 February 1917 | Driebergen | Netherlands | 1,884 | Sunk |
| 17 February 1917 | Ootmarsum | Netherlands | 2,313 | Sunk |
| 17 February 1917 | Trompenberg | Netherlands | 1,608 | Sunk |
| 21 February 1917 | Energy | United Kingdom | 25 | Sunk |
| 21 February 1917 | K.L.M. | United Kingdom | 28 | Sunk |
| 21 February 1917 | Monarch | United Kingdom | 35 | Sunk |
| 22 February 1917 | Ambon | Netherlands | 3,598 | Damaged |
| 11 March 1917 | HMS Bayard | Royal Navy | 220 | Damaged |
| 12 March 1917 | Einar Jarl | Norway | 1,849 | Sunk |
| 12 March 1917 | Forget-Me-Not | United Kingdom | 40 | Sunk |
| 12 March 1917 | Glynymel | United Kingdom | 1,394 | Sunk |
| 12 March 1917 | Memnon | United Kingdom | 3,203 | Sunk |
| 12 March 1917 | Reindeer | United Kingdom | 52 | Sunk |
| 13 March 1917 | Try | United Kingdom | 34 | Sunk |
| 17 March 1917 | City of Memphis | United States | 5,252 | Sunk |
| 17 March 1917 | HMS Mignonette | Royal Navy | 1,250 | Sunk |
| 18 March 1917 | HMS Alyssum | Royal Navy | 1,250 | Sunk |
| 19 March 1917 | Armoricain | France | 261 | Sunk |
| 20 March 1917 | HMHS Asturias | Royal Navy | 12,002 | Damaged |
| 20 March 1917 | Hazelpark | United Kingdom | 1,964 | Sunk |
| 21 March 1917 | Avance | United Kingdom | 57 | Sunk |
| 22 March 1917 | Efeu | Norway | 569 | Sunk |
| 17 April 1917 | Clan Sutherland | United Kingdom | 2,820 | Damaged |
| 22 April 1917 | Arethusa | United Kingdom | 1,279 | Sunk |
| 23 April 1917 | HMT Rose II | Royal Navy | 213 | Sunk |
| 27 April 1917 | Quantock | United Kingdom | 4,470 | Damaged |
| 1 May 1917 | Bagdale | United Kingdom | 3,045 | Sunk |
| 1 May 1917 | John W. Pearn | United Kingdom | 76 | Sunk |
| 1 May 1917 | La Manche | France | 335 | Sunk |
| 25 May 1917 | Sjaelland | United Kingdom | 1,405 | Sunk |