SM UC-70 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 12 January 1916 and was launched on 7 August 1916. She was commissioned into the German Imperial Navy on 20 November 1916 as SM UC-70.[1] In ten patrols UC-70 was credited with sinking 33 ships, either by torpedo or by mines laid. On 28 August 1918, UC-70 was spotted lying submerged on the sea bottom and attacked by a Blackburn Kangaroo patrol aircraft of No. 246 Squadron RAF and then was then sunk by depth charges from the British destroyer . The wreck is a Protected Wreck managed by Historic England.
A Type UC II submarine, UC-70 had a displacement of 427t when at the surface and 508t while submerged. She had a length overall of 50.35m (165.19feet), a beam of 5.22m (17.13feet), and a draught of 3.64m (11.94feet). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 300PS (a total of 600PS), two electric motors producing 620PS, 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-70 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] | |
|---|---|---|---|---|---|
| 14 February 1917 | Marthe Yvonne |  France | 30 | Sunk | |
| 16 March 1917 | Cordouan | France | 28 | Sunk | |
| 16 March 1917 | Margaret VI | 852 | Damaged | ||
| 17 March 1917 | Alcide Marie | France | 26 | Sunk | |
| 17 March 1917 | Camille Emile | France | 20 | Sunk | |
| 17 March 1917 | Dieu Te Garde | France | 30 | Sunk | |
| 17 March 1917 | Juliette | France | 29 | Sunk | |
| 17 March 1917 | Louis XIV | France | 44 | Sunk | |
| 17 March 1917 | Notre Dame Du Perpetuel Secours | France | 29 | Sunk | |
| 17 March 1917 | Nozal | France | 34 | Sunk | |
| 17 March 1917 | Renee Islander | France | 25 | Sunk | |
| 17 March 1917 | Rupella | France | 38 | Sunk | |
| 17 March 1917 | Tasso |  United Kingdom | 1,859 | Sunk | |
| 18 March 1917 | Madone | France | 31 | Sunk | |
| 18 March 1917 | Entente Cordiale | France | 22 | Sunk | |
| 18 March 1917 | Felicite Albert | France | 32 | Sunk | |
| 18 March 1917 | Hyacinthe Yvonne | France | 43 | Sunk | |
| 19 March 1917 | Bergsli |  Norway | 2,133 | Sunk | |
| 19 March 1917 | Michel | France | 1,773 | Sunk | |
| 24 March 1917 | Tapir | France | 200 | Sunk | |
| 16 April 1917 | Eduard | United Kingdom | 476 | Sunk | |
| 17 April 1917 | Nirvana | United Kingdom | 6,021 | Damaged | |
| 30 April 1917 | Eden | Norway | 1,304 | Sunk | |
| 7 May 1917 | Lowmount | United Kingdom | 2,070 | Sunk | |
| 18 May 1917 | C.E.C.G. | United Kingdom | 47 | Sunk | |
| 18 May 1917 | Dromore | United Kingdom | 268 | Sunk | |
| 23 May 1917 | Begona N°3 |  Spain | 2,699 | Sunk | |
| 27 May 1917 | General De Boisdeffre | France | 2,195 | Sunk | |
| 28 May 1917 | Ancona | United Kingdom | 1,168 | Sunk | |
| 27 May 1918 | Wayside Flower | United Kingdom | 21 | Sunk | |
| 28 May 1918 | Coronation | United Kingdom | 19 | Sunk | |
| 4 June 1918 | Cento | United Kingdom | 3,708 | Damaged | |
| 9 July 1918 | Frederika |  Netherlands | 91 | Sunk | |
| 17 July 1918 | Elin | Norway | 139 | Damaged | |
| 21 July 1918 | Genesee | United Kingdom | 2,830 | Damaged | |
| 21 July 1918 | Mongolian | United Kingdom | 4,892 | Sunk | |
| 23 July 1918 | Boorara |  Australia | 6,570 | Damaged | |
| 24 July 1918 | Kilkis |  Greece | 4,302 | Sunk | |
| 26 July 1918 | Ango | France | 7,393 | Damaged | |
| 28 August 1918 | Giralda | United Kingdom | 1,100 | Sunk |
UC-70 was depth charged and sunk off Whitby, Yorkshire on 28 August 1918 with the loss of all 31 crew. The wreck was given protected status by Historic England in 2017.[4]