SM UC-25 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy (de|Kaiserliche Marine) during World War I. The U-boat was ordered on 29 August 1915 and was launched on 10 June 1916. She was commissioned into the German Imperial Navy on 28 June 1916 as SM UC-25.[1] In 13 patrols UC-25 was credited with sinking 21 ships, either by torpedo or by mines laid. From March to September 1918, she was commanded by Karl Dönitz, later grand admiral in charge of all U-boats in World War II. UC-25 was scuttled at Pola on 28 October 1918 on the surrender of Austria-Hungary.
A Type UC II submarine, UC-25 had a displacement of 400t when at the surface and 480t while submerged. She had a length overall of 49.45m (162.24feet), a beam of 5.22m (17.13feet), and a draught of 3.68m (12.07feet). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 250PS (a total of 500PS), two electric motors producing 460PS, and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of .
The submarine had a maximum surface speed of and a submerged speed of . When submerged, she could operate for at ; when surfaced, she could travel at . UC-25 was fitted with six mine tubes, eighteen UC 200 mines, three torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 8.8sp=usNaNsp=us Uk L/30 deck gun. Her complement was twenty-six crew members.
| Date | Name | Nationality | Tonnage[2] | Fate[3] | |
|---|---|---|---|---|---|
| 19 October 1916 | Jug | 75 | Sunk | ||
| 6 December 1916 | Shchit | 248 | Sunk | ||
| 6 April 1917 | Cybele |  France | 148 | Sunk | |
| 7 April 1917 | Edwin R. Hunt |  United States | 1,132 | Sunk | |
| 28 April 1917 | Juliette | France | 50 | Sunk | |
| 15 May 1917 | 703 | Sunk | |||
| 16 May 1917 | 5,250 | Damaged | |||
| 24 May 1917 | Domenico Barone | 171 | Sunk | ||
| 28 May 1917 | Nuovo S. Giovanni | 31 | Sunk | ||
| 28 May 1917 | San Domenico | 27 | Sunk | ||
| 31 May 1917 | Ninotto | 208 | Sunk | ||
| 1 June 1917 | Domenico Miscuraca | 194 | Sunk | ||
| 1 June 1917 | Vittoria | 248 | Sunk | ||
| 6 June 1917 | Mitra |  United Kingdom | 5,592 | Damaged | |
| 4 July 1917 | HMS Aster | 1,250 | Sunk | ||
| 4 July 1917 | HMS Azalea | 1,250 | Damaged | ||
| 5 July 1917 | Eburna | United Kingdom | 4,735 | Damaged | |
| 17 October 1917 | HMHS Goorkha | 6,335 | Damaged | ||
| 18 October 1917 | Anna Scotto | 594 | Sunk | ||
| 20 October 1917 | Virginia Gentile | 164 | Sunk | ||
| 3 December 1917 | Melo | 1,115 | Sunk | ||
| 8 December 1917 | Chyebassa | United Kingdom | 6,249 | Damaged | |
| 23 February 1918 | HMT Marion | 255 | Sunk | ||
| 18 March 1918 | Massilia | 5,026 | Sunk | ||
| 4 April 1918 | Agatina | 201 | Sunk | ||
| 28 July 1918 | Vesuvio | 5,459 | Damaged | ||
| 29 July 1918 | Rio Pallaresa | United Kingdom | 4,043 | Sunk | |
| 5 August 1918 | Freshfield |  Canada | 3,445 | Sunk |