SM UC-31
Date Name Nationality Tonnage Fate
31 December 1916 Protector United Kingdom 200 Sunk
4 January 1917 Lonclara United Kingdom 1,294 Sunk
25 January 1917 O . B. Suhr Denmark 1,482 Sunk
28 January 1917 Alexandra United Kingdom 179 Sunk
29 January 1917 Shamrock United Kingdom 173 Sunk
29 January 1917 Thistle United Kingdom 167 Sunk
31 January 1917 Ravensbourne United Kingdom 1,226 Sunk
24 February 1917 Beneficent United Kingdom 1,963 Sunk
29 March 1917 Kathleen Lily United Kingdom 521 Sunk
30 March 1917 Harberton United Kingdom 1,443 Sunk
4 April 1917 Helga Denmark 839 Sunk
5 April 1917 N. J. Fjord Denmark 1,425 Sunk
6 April 1917 HMT Strathrannoch Royal Navy 215 Sunk
11 April 1917 Quaggy United Kingdom 993 Sunk
12 April 1917 Dina Hinderika Netherlands 200 Sunk
12 April 1917 Neptunus Netherlands 209 Sunk
12 April 1917 Union Denmark 152 Sunk
12 April 1917 Voorwaarts Netherlands 147 Sunk
14 April 1917 Spray United Kingdom 1,072 Sunk
15 April 1917 Brothertoft United Kingdom 155 Sunk
Summary of raiding history
SM UC-31 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy () during World War I. The U-boat was ordered on 29 August 1915 and was launched on 7 August 1916. She was commissioned into the German Imperial Navy on 2 September 1916 as SM UC-31. In 13 patrols UC-31 was credited with sinking 38 ships, either by torpedo or by mines laid. UC-31 was surrendered on 26 November 1918 and broken up at Canning Town in 1922.