SM UC-4 was a German Type UC I minelayer submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The U-boat had been ordered by November 1914 and was launched on 6 June 1915. She was commissioned into the German Imperial Navy on 10 June 1915 as SM UC-4.[1] Mines laid by UC-4 in her 73 patrols were credited with sinking 36 ships. UC-4 was scuttled off the coast of Flanders during the German evacuation on 5 October 1918.
A Type UC I submarine, UC-4 had a displacement of 168t when at the surface and 183t while submerged. She had a length overall of 33.99m (111.52feet), a beam of 3.15m (10.33feet), and a draught of 3.040NaN0. The submarine was powered by one Daimler-Motoren-Gesellschaft six-cylinder, four-stroke diesel engine producing 90PS, an electric motor producing 175PS, and one propeller shaft. She was capable of operating at a depth of .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, she could operate for at ; when surfaced, she could travel at . UC-4 was fitted with six mine tubes, twelve UC 120 mines, and one 8mm machine gun. She was built by AG Vulcan Stettin and her complement was fourteen crew members.
| Date | Name | Nationality | Tonnage[2] | Fate[3] | |
|---|---|---|---|---|---|
| 15 August 1915 | Ladoga | 6,136 | Sunk | ||
| 16 August 1915 | Linnea (n-1) | 739 | Sunk | ||
| 12 February 1916 | Aduatiek |  Belgium | 2,221 | Sunk | |
| 12 February 1916 | Cedarwood |  United Kingdom | 654 | Sunk | |
| 13 February 1916 | Tergestea | United Kingdom | 4,308 | Sunk | |
| 29 February 1916 | Den of Ogil | United Kingdom | 5,689 | Damaged | |
| 27 October 1916 | Bygdo |  Norway | 2,345 | Sunk | |
| 28 October 1916 | Sparta | United Kingdom | 480 | Sunk | |
| 9 November 1916 | Sunniside | United Kingdom | 447 | Sunk | |
| 25 November 1916 | HMT Burnley | 275 | Sunk | ||
| 3 December 1916 | HMT Remarko | 245 | Sunk | ||
| 5 December 1916 | HMT Tervani | 457 | Sunk | ||
| 7 January 1917 | HMT Donside | 182 | Sunk | ||
| 18 January 1917 | Dagmar |  Denmark | 758 | Sunk | |
| 20 January 1917 | HMT New Comet | 177 | Sunk | ||
| 13 February 1917 | HMT Sisters Melville | 260 | Sunk | ||
| 23 February 1917 | Grenadier | United Kingdom | 1,004 | Sunk | |
| 11 March 1917 | Kwasind | United Kingdom | 2,211 | Sunk | |
| 12 March 1917 | Ambient | United Kingdom | 1,517 | Sunk | |
| 12 March 1917 | Pontypridd | United Kingdom | 1,556 | Sunk | |
| 3 June 1917 | Giralda | United Kingdom | 46 | Sunk | |
| 4 July 1917 | Chrysolite | United Kingdom | 57 | Sunk | |
| 7 July 1917 | HMT Kelvin | 322 | Sunk | ||
| 20 July 1917 | HMS Queen of the North | 594 | Sunk | ||
| 5 September 1917 | HMT Eros | 286 | Sunk | ||
| 20 October 1917 | HMT Vitality | 202 | Sunk | ||
| 11 November 1917 | Lapwing | United Kingdom | 1,192 | Sunk | |
| 13 November 1917 | Axminster | United Kingdom | 1,905 | Sunk | |
| 23 December 1917 | Grantley Hall | United Kingdom | 4,008 | Sunk | |
| 25 February 1918 | Rubio | United Kingdom | 2,395 | Sunk | |
| 26 February 1918 | Berwen | United Kingdom | 3,752 | Damaged | |
| 5 March 1918 | Coalgas | United Kingdom | 2,257 | Sunk | |
| 5 March 1918 | Estrella | United Kingdom | 1,740 | Sunk | |
| 5 March 1918 | Tusnastabb | Norway | 1,136 | Sunk | |
| 12 April 1918 | Lonhelen | United Kingdom | 1,281 | Sunk | |
| 20 April 1918 | HMT Numitor | 242 | Sunk | ||
| 25 April 1918 | HMS St. Seiriol | 928 | Sunk | ||
| 26 June 1918 | HMT Achilles II | 225 | Sunk |