List of shipwrecks in September 1917

The list of shipwrecks in September 1917 includes some ships sunk, foundered, grounded, or otherwise lost during September 1917.

1 September

 *  Akaroa (🇳🇴 Norway): World War I: The barque was sunk in the English Channel 70 nmi west of the Casquets, Channel Islands by SMU U-19 (Germany) . Her crew survived.
 * SS Amiral Olry (1904) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 38 nmi north west of Cape Sidero, Crete, Greece (35.66667°N, 25.78333°W) by SMU UC-74.
 * SS Dront (1907) ( undefined): World War I: The cargo ship was sunk in the Barents Sea 110 nmi north west by north of the North Cape, Norway by SMU U-28 (Germany).
 * SS Fingal ( undefined): The cargo ship foundered on this date.
 * SS Erato (1907) ( undefined): World War I: The cargo ship struck a mine and sank in the English Channel 4 nmi south east of The Lizard, Cornwall. Her crew survived.
 * SS Peronne (1882) (🇫🇷 France): World War I: The cargo ship was sunk in the English Channel 5 nmi south east of Berry Head, Devon, United Kingdom by SMU UC-65 . Her crew survived.
 *  Tarapaca (🇫🇷 France): World War I: The four-masted full-rigged ship was scuttled in the Bay of Biscay 65 nmi west of the La Coubre Lighthouse, Charente-Maritime (45.91667°N, -3.2°W) by SMU U-52.

2 September

 *  Caracas (🇳🇴 Norway): World War I: The auxiliary sailing vessel was scuttled in the Atlantic Ocean 130 nmi north west of Cape Finisterre, Spain (46°N, -11.06667°W) by SMU UB-49 . Her crew survived.
 * HMS Dundee (1909) : World War I: The armed boarding steamer was torpedoed and damaged in the Atlantic Ocean south west of the Isles of Scilly (48.83333°N, -9.33333°W) by SMU UC-49 with the loss of nine lives. She sank the next day.
 * Ker Durand (🇫🇷 France): World War I: The fishing vessel was scuttled in the Atlantic Ocean 70 nmi west of Ar Men, Finistère by SMU UC-69 . Her crew survived.
 * SS Olive Branch (1912) ( undefined): World War I: The cargo ship was shelled and sunk in the Barents Sea 85 nmi north by east of the North Cape, Norway (72.56667°N, 27.93333°W) by SMU U-28 (Germany) with the loss of a crew member.
 * SS Rytonhall (1905) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 105 nmi west of Ouessant, Finistère (47.75°N, -7.46667°W) by SMU UC-69 . Her crew survived.
 * SMU U-28 (Germany) : World War I: The Type U 27 submarine was sunk in the Barents Sea 85 nmi north by east of the North Cape (72.56667°N, 27.93333°W) by the explosion of the cargo of munitions aboard SS Olive Branch (1912), ( undefined) which it had attacked. All 39 crew were killed.
 * SS Wentworth (1913) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Bay of Biscay 36 nmi (47°N, -3.38333°W by SMU U-52 with the loss of a crew member. Three survivors were taken as prisoners of war.

3 September

 * Agios Andreas (🇬🇷 Greece): World War I: The sailing vessel was sunk in the Aegean Sea by SMU UC-74.
 * SS Alentejo (1911) (🇵🇹 Portugal): The cargo ship caught fire, exploded and sank at Marseille, Bouches-du-Rhône, France.
 * HMS Begonia (1915) : World War I: The Azalea-class sloop departed on patrol in the Atlantic Ocean. She was subsequently sunk by enemy action with the loss of 94 crew.
 * HMT Italy : The naval trawler was lost on this date.
 * SS La Negra (1913) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 50 nmi south south west of Start Point, Devon (49.48333°N, -3.88333°W) by SMU UC-50 with the loss of four of her crew.
 * SS Majoren (1887) (🇳🇴 Norway): World War I: The cargo ship was sunk in the Atlantic Ocean north west of Bloody Foreland, County Donegal, United Kingdom (55.23333°N, -8.93333°W) by SMU U-95 . Her crew survived.
 * SS Ragnhild (1895) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 14 nmi south by east of Flamborough Head, East Riding of Yorkshire by SMU UB-30 with the loss of fifteen crew.
 * SS Treverbyn (1910) ( undefined): World War I: The cargo ship struck a mine and sank in the Atlantic Ocean 2 nmi east south east of the Ushinish Lighthouse, South Uist, Outer Hebrides with the loss of 27 crew.
 *  Van Allens-Broughton (🇺🇸 United States): The five-masted schooner was abandoned in the Atlantic Ocean. She sank the next day.

4 September

 * SS Bishopton (1916) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 30 nmi south by east of St. Catherine's Point, Isle of Wight (50.13333°N, -0.95°W) by SMU UC-16 with the loss of two of her crew.
 * SS Peerless (1898) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean south west of the Bishop Rock, Isles of Scilly (49.18333°N, -7.26667°W) by SMU U-52 with the loss of five crew. Three survivors were taken as prisoners of war.
 *  Sadi Carnot (🇫🇷 France): World War I: The three-masted schooner was sunk in the Atlantic Ocean 42 nmi south south west of the Isles of Scilly by SMU UC-69 . Her crew were rescued by HMS Landrail ( and Montana (🇺🇸 United States).
 * SS Theodora (1894) (🇬🇷 Greece): World War I: The cargo ship was sunk in the Atlantic Ocean off Santa Uxía de Ribeira, A Coruña, Spain (42.53333°N, -9.41667°W) by SMU UB-49 . Her crew survived.

5 September

 * SS Alesia (1902) (🇫🇷 France): World War I: The passenger ship was torpedoed and damaged in the Atlantic Ocean 40 nmi north west of Ouessant, Finistère by SMU UC-69 . She was sunk the next day by SMU UC-50.
 * SS Echunga (1907) ( undefined): World War I: The tanker was torpedoed and sunk in the Atlantic Ocean 40 nmi north east of Ouessant by SMU U-52 with the loss of nine crew.
 * Emma ( undefined): World War I: The sailing vessel was shelled and sunk in the English Channel 8 nmi north of Sept-Îles, Finistère, France by SMU UC-50.
 * HMT Eros : World War I: The naval trawler struck a mine and sank in the North Sea off Orfordness, Suffolk with the loss of two of her crew.
 *  Florence Muspratt ( undefined): World War I: The schooner was shelled and sunk in the English Channel 10 nmi north of Sept-Îles by SMU UC-50 . Her crew survived.
 * Frances ( undefined): World War I: The ketch was scuttled in the English Channel 8 nmi north by west of Sept-Îles by SMU UC-50 . Her crew survived.
 *  Glynn ( undefined): World War I: The schooner was shelled and sunk in the English Channel 32 nmi north west of the Les Hanois Lighthouse, Guernsey, Channel Islands by SMU UC-42 . Her crew survived.
 *  Industry ( undefined): World War I: The schooner was shelled and sunk in the English Chaanel 20 nmi north west of the Les Hanois Lighthouse by SMU UC-42 . Her crew survived.
 * Jeannot (🇧🇪 Belgium): World War I: The fishing vessel was scuttled in the North Sea off Lowestoft, Suffolk by SMU UB-10 . Her crew survived.
 * Margaret ( undefined): World War I: The trawler struck a mine and sank in the North Sea off Wick, Caithness with the loss of five of her crew.
 * Proletaire (🇫🇷 France): World War I: The sailing vessel was scuttled in the Mediterranean Sea 59 nmi off Cape Bougarouni, Algeria (37.75°N, 5.75°W) by SMU U-63 (Germany).
 * Theodor ( undefined): World War I: The sailing vessel was scuttled in the English Channel 13 nmi north by west of Sept-Îles by SMU UC-50 . Her crew survived.
 * SMU U-88 : World War I: The Type U 87 submarine struck a mine and sank in the North Sea off Terschelling, Friesland, Netherlands with the loss of all 43 crew.
 * Unity ( undefined): World War I: The fishing smack was scuttled in the North Sea 8 nmi east of the Cross Sand Lightship ( undefined) by SMU UB-10 . Her crew survived.

6 September

 *  Agios Georgios (🇬🇷 Greece): World War I: The barque was sunk in the Ionian Sea (36.25°N, 21.73333°W) by SMU UC-74.
 * SS Elisabethville (1910) (🇧🇪 Belgium): World War I: The passenger ship was torpedoed and sunk in the Bay of Biscay (47.08333°N, -3.06667°W) by SM UC-71 with the loss of fourteen of the 313 people on board.
 * HMS Fiona (1905) : The armed boarding steamer was lost on this date.
 * SS Hammar II (1912) (🇸🇪 Sweden): World War I: The cargo ship was scuttled in the North Sea by SMU UB-62 . Her eleven crew were took to the lifeboats but were not rescued.
 * HMT Helgian : World War I: The naval trawler struck a mine and sank in the Gulf of Ruphani with the loss of ten of her twelve crew.
 * Moina (🇫🇷 France): World War I: The auxiliary sailing vessel was scuttled in the Atlantic Ocean west of Gibraltar (36.53333°N, -7.25°W) by SMU UB-49 . Her crew survived.
 * Rosary ( undefined): World War I: The fishing smack was scuttled in the North Sea off the coast of Norfolk by SMU UB-10 . Her crew survived.
 * SS Thisbe (1910) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 6 nmi west of The Lizard, Cornwall, United Kingdom (49.95°N, -5.35°W) by SMU UB-35.
 * SS Tuskar (1890) ( undefined): World War I: The cargo ship struck a mine and sank in the Atlantic Ocean 3 nmi off Eagle Island, County Mayo with the loss of ten of her crew.
 * SS Ville de Strasbourg (1882) (🇫🇷 France): World War I: The cargo ship was sunk in the Aegean Sea off Cape Spati, Cythera, Greece (36.4°N, 22.9°W) by SMU UC-74 . Her crew survived.

7 September

 * ST Antonio Ferro ( undefined): The tug foundered on this date with the loss of seven of her crew.
 * HMT By George : World War I: The naval trawler struck a mine and sank in the Gulf of Ruphani (40.63333°N, 34.9°W) with the loss of two of her crew.
 * Casa Blanca (🇵🇹 Portugal): World War I: The sailing vessel was sunk in the Atlantic Ocean by SMU UB-49.
 * SS Clan Ferguson (1898) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 15 nmi off Cape Spartel, Morocco (35.83333°N, -6.16667°W) by SMU UB-49 with the loss of ten crew.
 * SS Grelfryda (1917) ( undefined): World War I: The cargo ship was torpedoed and damaged in the North Sea 4 nmi south west by west of Flamborough Head, Yorkshire by SMU UB-34 . She was beached, but was later refloated, repaired and returned to service.
 * SS Haakon VII (1907) (🇳🇴 Norway): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 3 nmi east south east of Land's End, Cornwall, United Kingdom by SMU UB-35 with the loss of three of her crew.
 *  Hinemoa ( undefined): World War I: The four-masted barque was shelled and sunk in the Atlantic Ocean 35 nmi west south west of the Bishop Rock, Isles of Scilly (49.5°N, -7.13333°W) by SMU UC-16 . Her crew survived.
 * SS Hunsbridge (1912) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 60 nmi west south west of Cape Spartel (35.16667°N, -6.83333°W) by SMU UB-49 with the loss of three of her crew.
 * SS Minnehaha ( undefined): World War I: The ocean liner was torpedoed and sunk in the Atlantic Ocean 12 nmi south east of the Fastnet Rock (51.28333°N, -9.36667°W) by SMU U-48 with the loss of 43 lives.
 * Mont de Piete (🇫🇷 France): World War I: The vessel was sunk in the Bay of Biscay off the mouth of the Loire by SMU UC-71.
 * SS Myrmidon (1905) ( undefined): World War I: The cargo ship was damaged in the Mediterranean Sea (37.16667°N, 6.85°W by SMU UC-54 with the loss of two of her crew. She was beached at Philippeville, Algeria but was later refloated.
 * Versailles (🇫🇷 France): World War I: The fishing vessel was shelled and sunk in the Atlantic Ocean 107 nmi south by west of Ouessant, Finistère (47.81667°N, -7.63333°W) by SMU UC-50 . Her crew survived.
 *  Vestfjeld (🇳🇴 Norway): World War I: The four-masted barque was sunk in the Atlantic Ocean 40 nmi south west of the Bishop Rock by SMU UC-16 . Her crew survived.

8 September

 * SS Aladdin (1902) (🇳🇴 Norway): World War I: The coaster was sunk in the North Sea 5 nmi north by west of Flamborough Head, Yorkshire, United Kingdom by SMU UB-34 with the loss of a crew member.
 * Armorique (🇫🇷 France): World War I: The sailing vessel was sunk in the Atlantic Ocean north of Ouessant, Finistère by SMU UB-35.
 * SS Askelad (1894) (🇳🇴 Norway): World War I: The cargo ship was sunk in the Atlantic Ocean west south west of Ouessant (47.41667°N, -7.41667°W) by SMU UC-17 . Her crew survived.
 *  Blanche (🇫🇷 France): World War I: The schooner was sunk in the Atlantic Ocean north of Ouessant by SMU UB-35.
 * Elizabeth ( undefined): World War I: The schooner was scuttled in the English Channel 12 nmi east south east of Start Point, Devon by SMU UB-31 . Her crew survived.
 *  Ezel ( undefined): World War I: The schooner was shelled and sunk in the English Channel 20 nmi north of Saint-Valery-en-Caux, Seine-Maritime, France (50.21667°N, 0.6°W) by SMU UC-51 . Her crew survived.
 * Family's Pride ( undefined): World War I: The vessel was scuttled in the North Sea 28 nmi east of Peterhead, Aberdeenshire by SMU UC-40.
 * SS Harrow (1900) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 4 nmi south east of Whitby, Yorkshire by SMU UB-41 with the loss of two of her crew.
 * SS Hockwold (1911) ( undefined): The collier collided with another British merchant ship and sank in the English Channel off The Lizard, Cornwall.
 *  Laura ( undefined): World War I: The ketch was scuttled in the English Channel 25 nmi north of Fécamp, Seine-Maritime by SMU UC-51 . Her crew survived.
 *  Meeta ( undefined): World War I: The schooner was sunk in the Atlantic Ocean north of Ouessant by SMU UB-35.
 * SS Newholm (1899) ( undefined): World War I: The cargo ship was sunk in the English Channel 1 nmi south of Start Point, Devon by SMU UC-30 with the loss of twenty of her crew.
 * SS Setubal (1898) (🇳🇴 Norway): World War I: The cargo ship was scuttled in the English Channel 25 nmi north east of Ouessant (48.91667°N, -4.58333°W) by SMU UC-71 . Her crew survived.
 *  William H. Clifford (🇺🇸 United States): World War I: The four-masted schooner was sunk in the Atlantic Ocean (48.5°N, -12.33333°W) by SMU UB-50 . Her crew survived.

9 September

 *  Elsa (🇩🇰 Denmark): World War I: The barque was torpedoed and sunk in the Atlantic Ocean 6 nmi off Kinsale, County Cork, United Kingdom by SMU U-48 with the loss of five crew.
 * SS Pluton (1889) (🇳🇴 Norway): World War I: The cargo ship was torpedoed and sunk in the English Channel 6 nmi east south east of Start Point, Devon by SMU UB-31 with the loss of ten of her crew.
 * SS Storm ( undefined): World War I: The coaster was torpedoed and sunk in the North Sea 1 nmi off the Sunk Lightship ( undefined) by a Luftstreitkräfte aircraft.
 * SS Swiftsure (1894) ( undefined): World War I: The coaster struck a mine and sank in Shapinsay Sound, Orkney Islands with the loss of a crew member.

10 September

 * SS City of Nagpur (1914) ( undefined): The cargo ship ran aground on the Danae Shoal, off Lourenço Marques, Mozambique. She broke in two and was a total loss. All 259 passengers, and her crew, were rescued.
 * SS Eburoon (🇧🇪 Belgium): The cargo ship was wrecked in Trepassey Bay, Newfoundland.
 * SS Jane Williamson (brigantine) ( undefined): World War I: The brigantine was shelled and sunk in the Atlantic Ocean 20 nmi north of St. Ives, Cornwall (50.53333°N, -5.33333°W) by SMU UC-51 with the loss of four of her six crew.
 * HMT Loch Ard : World War I: The naval trawler struck a mine and sank in the North Sea off Lowestoft, Suffolk (52.5°N, 1.88333°W) with the loss of five of her crew.
 * SS Margarita (1903) ( undefined): World War I: The cargo ship struck a mine and was severely damaged in the North Sea 1 nmi south of the Bressay Lighthouse, Shetland Islands. She was repaired and returned to service in 1921.
 * Mary Orr ( undefined): World War I: The sailing vessel was shelled and sunk in the Atlantic Ocean 8 nmi north by east of the Pendeen Lighthouse, Cornwall (50.3°N, -5.66667°W) by SMU UC-51 . Her crew survived.
 *  Mary Seymour ( undefined): World War I: The schooner was shelled and sunk in the Atlantic Ocean 7 nmi north north east of the Pendeen Lighthouse (50.26667°N, -5.65°W) by SMU UC-51 . Her crew survived.
 *  Moss Rose ( undefined): World War I: The three-masted schooner was shelled and sunk in the Atlantic Ocean 7 nmi north north east of the Pendeen Lighthouse (50.26667°N, -5.65°W) by SMU UC-51 . Her crew survived.
 * SS Parkmill (1909) ( undefined): The cargo ship was sunk in the North Sea 1.25 nmi south east of the Bressay Lighthouse by SMU UC-40 . Her crew survived.
 * Sims ( undefined): World War I: The tug sttruck a mine and sank in the Baltic Sea off Worms Island.
 * SMU UC-42 : World War I: The Type UC II submarine was sunk by the explosion of one of her own mines at Cork, Ireland (51.73333°N, -8.2°W) with the loss of all 26 crew.
 * SS Vikholmen (1916) (🇳🇴 Norway): World War I: The coaster was sunk in the English Channel south east of the Isle of Wight, United Kingdom (50.18333°N, -1.36667°W) by SMU UC-71 with the loss of eight of her crew.
 *  Water Lily ( undefined): World War I: The schooner was sunk in the Atlantic Ocean 8 nmi north north east of the Pendeen Lighthouse (50.3°N, -5.66667°W) by SMU UC-51 . Her crew survived.

11 September

 * SS Embleton (1917) ( undefined): World War I: The cargo ship was sunk in the Atlantic Ocean 150 nmi west of Cape Spartel, Morocco by SMU U-63 (Germany) . Her crew survived.
 * SS Luxembourg (1910) ( undefined): World War I: The cargo ship struck a mine and sank in the Atlantic Ocean 3.5 nmi north north east of the Pendeen Lighthouse, Cornwall (50.21667°N, -5.66667°W) by SMU UC-51 . Her crew survived.
 * Rosy Cross ( undefined): World War I: The fishing smack was scuttled in the Atlantic Ocean 4 nmi north west by west of Crackington Haven, Cornwall by SMU UC-51 . Her crew survived.
 * SS Tobol (1901) ( undefined): World War I: The cargo ship was sunk in the North Sea 70 nmi east south east of Duncansby Head, Caithness, United Kingdom (58.16667°N, -1°W) by SMU U-52.
 * SMU U-49 : World War I: The Type U 43 submarine was rammed, shelled and sunk in the Bay of Biscay (46.28333°N, -14.7°W) by SS British Transport ( undefined} with the loss of all 43 crew.
 * SS Vienna (1899) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Bay of Biscay 340 nmi west of Ouessant, Finistère, France (46.98333°N, -13.08333°W) by SMU U-49 with the loss of 25 crew. Her captain was taken as a prisoner of war.
 *  William ( undefined): World War I: The schooner was sunk in the Atlantic Ocean 4 nmi north north west of Crackington Haven (50.93333°N, -5.65°W) by SMU UC-51 . Her crew survived.

12 September

 *  Agricola ( undefined): World War I: The schooner was scuttled in the Bristol Channel 15 nmi west north west of Lundy Island, Devon by SMU U-19 (Germany) . Her crew survived.
 * HMT Asia : World War I: The naval trawler struck a mine and sank in the North Sea off Bressay, Shetland Islands with the loss of seven of her crew.
 * SS Deputé Pierre Goujon (1894) (🇫🇷 France): World War I: The cargo ship was sunk in the Bay of Biscay off Belle Île, Morbihan (47.1°N, -3.95°W) by SMU U-103 . Her crew survived.
 * SS Gibraltar (1902) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 100 nmi south east of Cape Creus, Spain (41.28333°N, 5.83333°W) by SMU UC-27 with the loss of four of her crew.
 * SS Gisla (1916) (🇳🇴 Norway): World War I: The cargo ship was sunk in the Mediterranean Sea 4 nmi off Cape Palos, Murcia Spain (37.65°N, -0.53333°W) by SMU U-64 (Germany) . Her crew survived.
 * ST HS 3 and RB 10 (both undefined): World War I: The tug and refrigerated barge were scuttled in the Atlantic Ocean 18 nmi west by north of Cape Sines, Portugal by SMU UB-50 . Her crew survived, but four of them were taken as prisoners of war.
 * SS Reim (1901) (🇳🇴 Norway): World War I: The cagro ship was sunk in the Atlantic Ocean off Cape St. Vincent, Portugal by SMU U-63 (Germany) . Her crew survived.
 * SS St. Margaret (1913) ( undefined): World War I: The passenger ship was torpedoed and sunk in the Norwegian Sea 30 nmi south east of Lítla Dímun, Faroe Islands by SMU U-103 with the loss of five crew.
 * SMU U-45 : World War I: The Type U 43 submarine was torpedoed and sunk in the Atlantic Ocean north west of the Shetland Islands, United Kingdom (55.8°N, -7.5°W) by HMS D7 with the loss of 43 of her 45 crew.
 * SS Urd (1895) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 10 nmi north by east of Cape Palos (37.86667°N, -0.46667°W) by SMU U-64 (Germany) with the loss of three crew.
 * SS Wilmore (1914) (🇺🇸 United States): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 4 nmi north east of the Hornigas Lighthouse, Cape Palos (37.68333°N, -0.51667°W) by SMU U-64 (Germany) . Her crew survived.

13 September

 * Arlequin (🇹🇳 Tunisia): World War I: The sailing vessel was sunk in the Gulf of Gabès by SMU UC-52 . Her crew survived.
 * ''Chère Rose' (🇹🇳) Tunisia: World War I: The sailing vessel was sunk in the Gulf of Gabès by SMU UC-52.
 * Comizianes da Graca (🇵🇹 Portugal): World War I: The sailing vessel was sunk in the Atlantic Ocean 6 nmi north of Cape Sines by SMU UB-50.
 * Correiro de Sines (🇵🇹 Portugal): World War I: The sailing vessel was sunk in the Atlantic Ocean off the coast of Portugal by SMU UB-50.
 * Ortigia (🇹🇳 Tunisia): World War I: The sailing vessel was sunk in the Gulf of Gabès by SMU UC-52.
 * SMU UC-21 : The Type UC II submarine departed Zeebrugge, West Flanders, Belgium for the Bay of Biscay. No further trace, presumed lost with all 26 crew.
 * Vittoria (🇹🇳 Tunisia): World War I: The sailing vessel was sunk in the Gulf of Gabès by SMU UC-52.
 * SS Zeta (1888) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 8 nmi south by west of Mine Head, County Cork by SMU UC-51 . Her crew survived.

14 September

 * SS Amiral de Kersaint (1903) (🇫🇷 France): World War I: The cargo ship was sunk in the Mediterranean Sea 5 nmi off Cape Tortosa, Spain by SMU U-64 (Germany).
 * SS Ausonia (1883) ( undefined): World War I: The cargo ship was sunk in the Mediterranean Sea off Cape Tortosa (40.76667°N, 1.05°W) by SMU U-64 (Germany) . Her crew survived.
 * SS Chulmleigh (1916) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 10 nmi south west by west of Cape Salou, Spain (40.9°N, 1.06667°W) by SMU U-64 (Germany) . Her crew survived.
 * USS D-2 (SS-18) : The D-class submarine sank at New London Naval Base, Connecticut. Her crew survived. She was subsequently refloated, repaired and returned to service.
 * Sado (🇵🇹 Portugal): World War I: The ship was sunk in the Atlantic Ocean 15 nmi south west of Cape Sines by SMU UB-50.
 * SS Saint Jacques (1909) (🇫🇷 France): The cargo ship struck a mine and sank in the Irish Sea 5 nmi south west of St. Ann's Head, Pembrokeshire, United Kingdom by SMU UC-51.

15 September

 *  Dependence ( undefined): World War I: The schooner was scuttled in the Atlantic Ocean off The Lizard, Cornwall by SMU UB-38 . Her crew survived.
 * SS Idomeneus (1899) ( undefined): World War I: The cargo ship was torpedoed and damaged in the North Channel (56.66667°N, -10.83333°W) by SMU U-67 with the loss of four crew. She was beached but was later refloated.
 * SS Platuria (1892) (🇺🇸 United States): World War I: The tanker was sunk in the Atlantic Ocean off Tangier, Morocco (35.13333°N, -9.25°W) by SMU U-63 (Germany) with the loss of ten crew.
 * SS Rollesby (1906) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 80 nmi east north east of Muckle Flugga, Shetland Islands by SMU U-48 . Her crew survived.
 * SS Santaren (1912) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 40 nmi north east of Muckle Flugga (61.6°N, -0.23333°W) by SMU UB-63 . Her crew survived.
 * SS Sommeina (1899) ( undefined): World War I: The cargo ship struck a mine and sank in the Atlantic Ocean 4 nmi south east of The Manacles (50.01667°N, -4.95°W). Her crew survived.

16 September

 * Annina Capano ( undefined): World War I: The sailing vessel was sunk in the Gulf of Lion (42.83333°N, 3.48333°W) by SMU UC-27.
 * Ann J. Trainer (🇺🇸 United States): World War I: The sailing vessel was sunk in the Atlantic Ocean 30 nmi off Ouessant, Finistère, France (48.73333°N, -5.65°W) by SMU UC-21 . Her crew survived.
 * SS Arabis (1914) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 210 nmi west by south of Ouessant (46.46667°N, -9.7°W) by SMU U-54 with the loss of twenty crew.
 * Eendracht VII (🇳🇱 Netherlands): World War I: The fishing vessel was scuttled in the North Sea 8 nmi off IJmuiden, North Holland by SMU UC-64 . Her crew survived.
 * SS Facto (1904) (🇳🇴 Norway): World War I: The cargo ship was torpedoed and sunk in Mount's Bay (49.96667°N, -5.6°W) by SMU UB-18 with the los of two of her crew.
 * HMS G9 : World War I: The G-class submarine was torpedoed, rammed and sunk in the North Sea by HMS Pasley (1916), which had mistaken her for a U-boat. All but one of her 31 crew were killed. The survivor was rescued by HMS Pasley.
 * Quatre Frères (🇫🇷 France): World War I: The fishing vessel was scuttled in the Atlantic Ocean 240 nmi west of the French coast by SMU UC-30.
 * SS Sandsend (1899) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 6 nmi south east by east of Mine Head, County Cork by SMU UC-48 with the loss of three of her crew.

17 September

 * SS Australia (1884) ) undefined): World War I: The cargo ship was sunk in the Atlantic Ocean 35 nmi north west of Muckle Flugga, Shetland Islands, United Kingdom by SMU UB-62 . Her crew survived.
 * Eugenio D. ( undefined): World War I: The sailing vessel was sunk in the Gulf of Lion by SMU UC-27.
 * Muccio ( undefined): World War I: The sailing vessel was sunk in the Gulf of Lion by SMU UC-27.
 * SS Niemen (🇫🇷 France): World War I: The cargo ship wassunk in the Atlantic Ocean 122 nmi north west of Cape Ortegal, Spain (45.88333°N, -8.1°W) by SMU U-54.
 * Our Bairns ( undefined): World War I: The fishing smack was scuttled in Irish Sea 25 nmi south west of the Coningbeg Lightship ( undefined) by SMU UC-48 . Her crew survived.
 * SS Paraciers (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the North Sea 12 nmi north of the Spurn Lightship ( undefined) by SMU UC-64 . Her crew survived.
 * SS Queen Amelia (1905) ( undefined): World War I: The cargo ship was sunk torpedoed, shelled, and sunk in the Atlantic Ocean 19 nmi north north east of Muckle Flugga by SMU UB-62 . Her crew survived.
 * Ronald ( undefined): World War I: The fishing smack was scuttled in Irish Sea 25 nmi south west of the Coningbeg Lightship ( undefined) by SMU UC-48 . Her crew survived.
 * SMU UC-45 : The Type UC II submarine sank in the North Sea (54.15°N, 7.58333°W with the loss of all 35 crew. She was later salvaged, repaired and returned to service.

18 September

 * SS Arendal (1885) (🇳🇴 Norway): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 115 nmi west of Cape Spartel, Morocco (35.45°N, -8.33333°W) by SMU U-63 (Germany) . Her crew survived.
 * Cachalot (🇹🇳 Tunisia): World War I: The sailing vessel was shelled and sunk in the Gulf of Gabès off the Kerkennah Islands (35.23333°N, 11.13333°W) by SMU UC-52 . Her crew survived.
 * HMS Contest (1913) : World War I: The Acasta-class destroyer was torpedoed and sunk in the Western Approaches (48.9°N, -7.05°W) by SMU U-106 with the loss of 35 of her 75 crew.
 * HMS Glenfoyle : World War I: The Q-ship was torpedoed and sunk in the Atlantic Ocean south west of Ireland (50.76667°N, -11.06667°W) by SMU U-43 (Germany) with the loss of eighteen crew.
 * SS Joseph Chamberlain (1910) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 50 nmi north by west of Muckle Flugga, Shetland Islands by SMU UB-62 with the loss of eighteen of her crew. Two survivors were taken as prisoners of war.
 * SS Polar Prince (1895) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 8 nmi south west of Cape Spartel, Morocco (35.5°N, -6.75°W) by SMU UB-50 . Her crew survived, but her captain was taken as a prisoner of war.
 * SS Port Kembla (1910) ( undefined): World War I: The cargo ship struck a mine and sank in the Atlantic Ocean off Cape Farewell, Greenland. Her crew were rescued.

19 September

 *  Blanche (🇫🇷 France): World War I: The four-masted barque was torpedoed and sunk in the Atlantic Ocean (47°N, -10.5°W) by SMU U-151 with the loss of eighteen crew.
 * SS Etal Manor (1916) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 7 nmi south by west of Hook Point, County Waterford by SMU UC-48 with the loss of six of her crew.
 *  Hydra (🇩🇰 Denmark): World War I: The three-masted schooner was shelled and sunk in the Atlantic Ocean west of the Orkney Islands, United Kingdom (59.55°N, -7.61667°W) by SMU U-94 with the loss of all six crew.
 *  Marthe Marguerite (🇫🇷 France): World War I: The three-masted barque was shelled and sunk in the Atlantic Ocean north west of Cape Finisterre, Spain (46.3°N, -11.41667°W) by SMU U-54 . Her crew survived.
 * SS Montana (1917) (🇳🇴 Norway): The cargo ship capsized and sank in the Mediterranean Sea off Tunis, Tunisia.
 * SS Saint Ronald (1910) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 95 nmi north north west of Tory Island, County Donegal (56.36667°N, -10.28333°W) by SMU U-82 sith the loss of 24 of her crew.
 * Teresita ( undefined): World War I: The sailing vessel was sunk in the Tyrrhenian Sea by SMU UC-53.

20 September

 * SS Fabian (1881) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 30 nmi off Cape Spartel, Morocco (35.75°N, -6.66667°W) by SMU UB-50 with the loss of three of her crew.
 * SS Gioffredo Mameli (1912) ( undefined): World War I: The cargo ship was sunk in the Atlantic Ocean 45 nmi north west of Cape Spartel (36.08333°N, -6.25°W) by SMU UB-50.
 * SS Kurdistan (1914) ( undefined): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 27 nmi east south east of Pantelleria, Italy (36.66667°N, 12.61667°W) by SMU U-32 (Germany) . Her crew survived.

21 September

 * SS Aline Montreuil (1900) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the English Channel 22 nmi north of Cap Barfleur, Manche (50.03333°N, -1.3°W) by SMU UB-38 . Her crew survived.
 * Christina ( undefined): World War I: The sailing vessel was sunk in the Tyrrhenian Sea by SMU UC-53.
 * SS Kouang-si (1904) (🇫🇷 France): World War I: The passenger ship was torpedoed and damaged in the English Channel 6 nmi south east of The Lizard, Cornwall, United Kingdom by SMU UC-48 . She was beached but was later refloated.
 * SS Radaas (1890) (🇩🇰 Denmark): World War I: The cargo ship was torpedoed and sunk in the English Channel 18 nmi west of Portland Bill, Dorset, United Kingdom (50.56667°N, -3.08333°W) by SMU UB-40 with the loss of a crew member.
 * Santo Nicola ( undefined): World War I: The sailing vessel was sunk in the Aegean Sea by SMU UC-23.
 * Spiridon (🇬🇷 Greece): World War I: The sailing vessel was sunk in the Aegean Sea by SMU UC-23.

22 September

 * SS Alkyon (1889) (🇬🇷 Greece): World War I: The cargo ship was sunk in the Mediterranean Sea off Oran, Algeria by SMU UB-50 . Her crew survived.
 *  Caroline (🇫🇷 France): World War I: The schooner was shelled and sunk in the Mediterranean Sea 60 nmi west of Asinara Island, Italy by SMU U-32 (Germany) . Her crew survived.
 *  Garifaglia (🇬🇷 Greece): World War I: The barque was scuttled in the Mediterranean Sea west of Crete (34.95°N, 22.23333°W) by SMU UC-38.
 * SS Greleen (1894) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 7 nmi east by north of Berry Head, Devon (50.46667°N, -3.23333°W) by SMU UB-40 with the loss of nineteen of her crew.
 * SS Italia (1898) (🇫🇷 France): World War I: The coaster was sunk in the Atlantic Ocean 11 nmi north west of Cape Ortegal, A Coruña, Spain by SMU UC-63.
 * SS John Knudsen (1916) (🇳🇴 Norway): World War I: The cargo ship was sunk in the Mediterranean Sea 20 nmi north of Cape Falcon, Algeria (36°N, -1.01667°W) by SMU UB-50 with the loss of a crew member.
 *  Mascotte (🇫🇷 France): World War I: The schooner was sunk in the English Channel 114 nmi off Ouessant, Finistère by SMU U-60 . Her crew survived.
 * Primo ( undefined): World War I: The sailing vessel was sunk in the Tyrrhenian Sea 3 nmi off the Fimara Grande Lightship ( undefined) by SMU UC-53.
 * SS Trongate (1897) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 5 nmi north west of Flamborough Head, Yorkshire by SMU UC-71  with the loss of two of her crew.
 * SS Ville de Valenciennes (1897) (🇫🇷 France): World War I: The cargo ship was sunk in the North Sea 5 nmi south east of Flamborough Head by SMU UC-64 . Her crew survived.

23 September

 *  Agios Nicolaos (🇬🇷 Greece): World War I: The schooner was shelled and sunk in the Mediterranean Sea west of Crete (35.55°N, 23.46667°W) by SMU UC-38.
 *  Argietta ( undefined): World War I: The brigantine was scuttled in the Tyrrhenian Sea by SMU UC-53.
 * Giuseppina Concertina ( undefined): World War I: The sailing vessel was sunk in the Tyrrhenian Sea by SMU UC-53.
 * Gloire (🇫🇷 France): World War I: The fishing vessel was scuttled in the Atlantic Ocean 240 nmi off Ouessant, Finistère by SMU U-60 . Her crew were rescued by the fishing vessel Algesiras (🇫🇷 France).
 * Henry Lippitt (🇺🇸 United States): World War I: The sailing vessel was scuttled in the Atlantic Ocean 200 nmi west of Brest, Finistère (48.28333°N, -10.08333°W) by SMU U-60 . Her crew survived.
 * SS Hornsund (1913)' ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 2.5 nmi east south east of Scarborough, Yorkshire by SMU UC-71 with the loss of a crew member.
 * SS Irthington (1897) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Gulf of Gioja 3 nmi east north east of Cape Vaticano, Italy (40.58333°N, 15.01667°W) by SMU UC-53 . Her crew survived.
 * Jeune Mathilde (🇫🇷 France): World War I: The fishing vessel was scuttled in the Atlantic Ocean 240 nmi west of Ouessant by SMU U-60 . Her crew were rescued by Algesiras (🇫🇷 France).
 * Joaquina (🇪🇸 Spain): World War I: The sailing vessel was sunk in the Mediterranean Sea 8 nmi off Cadaqués, Girona, Spain by SMU UC-27.
 * SS Medie (1911) (🇫🇷 France): World War I: The transport ship was sunk in the Mediterranean Sea 120 nmi north west of Cape Bougaroni, Algeria by SMU UC-27 with the loss of 250 of the 626 people on board.
 * Nicholaos (🇬🇷 Greece): World War I: The sailing vessel was sunk in the Aegean Sea by SMU UC-23.
 *  Perseverance ( undefined): World War I: The schooner was shelled and sunk in the English Channel 14 nmi north west by north of Saint-Valery-en-Caux, Seine-Maritime, France by SMU UC-47 . Her crew survived.
 * SS Rosehill ( undefined): World War I: The collier was torpedoed and damaged in the English Channel 5 nmi south west by south Fowey, Cornwall by SMU UB-40 . She was taken in tow but sank in Whitesand Bay (50.32778°N, -4.30694°W). Her crew survived.
 * SS St. Dunstan (1894) ( undefined): World War I: The dredger struck a mine and sank in the English Channel 12 nmi north west by west of Portland Bill, Dorset with the loss of two of her crew.

24 September

 *  Europe (🇫🇷 France): World War I: The four-masted barque was scuttled in the Atlantic Ocean (46.61667°N, -11.5°W) by SMU UC-63 . Her crew survived.
 * HMT Hastfen : World War I: The naval trawler struck a mine and sank in the North Sea with the loss of four of her crew.
 * SS Iriston (1916) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 7 nmi south by west of Cape Camarat, Var, France (43.28333°N, 6.81667°W) by SMU U-32 (Germany) . Her crew survived.
 * SS Leka (1892) (🇳🇴 Norway): World War I: The cargo ship was sunk in the North Sea 6 to 8 nmi east of Flamborough Head, Yorkshire, United Kingdom by SMU UC-71 with the loss of seventeen of her crew.
 * Louis Bossert (🇳🇴 Norway): World War I: The sailing vessel was sunk in the Bay of Biscay (45.18333°N, -9.58333°W) by SMU U-54 . Her crew survived.
 *  Mimosa (🇫🇷 France): World War I: The three-masted schooner was shelled and damaged in the Atlantic Ocean 25 nmi north west of the Isles of Scilly, United Kingdom by SMU UC-47 with the loss of a crew member. Survivors abandoned ship and were rescued or reached St. Mary's in their lifeboats. Mimosa was later towed in to St Mary's.
 * Nuova Francesca ( undefined): World War I: The sailing vessel was sunk in the Tyrrhenian Sea by SMU UC-53.
 *  Perseverance (🇫🇷 France): World War I: The four-masted barque was scuttled in the Atlantic Ocean by SMU UC-63 . Her crew survived.
 * S. Espedito ( undefined): World War I: The sailing vessel was sunk in the Tyrrhenian Sea by SMU UC-53 . Her crew survived.

25 September

 * SS Boynton (1892) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 5 nmi west north west of Cape Cornwall (50.08333°N, -5.91667°W) by SMU UC-47 with the loss of 23 of her crew.
 * SS City of Swansea (1882) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 15 nmi east north east of Berry Head, Devon by SMU UB-40 with the loss of two of her crew.
 * SS Dinorah (1912) (🇫🇷 France): World War I: The cargo ship was sunk in the Atlantic Ocean (approximately 46.75°N, -12°W) by SMU UC-63.
 *  Edouard Detaille (🇫🇷 France): World War I: The barque was torpedoed and sunk in the Atlantic Ocean (46°N, -9.5°W) by SMU U-60 . Her crew survived.
 * HMT James Seckar : World War I: The naval trawler was sunk in the Atlantic Ocean (approximately 46.75°N, -12°W) by SMU UC-63 with the loss of sixteen of her crew.
 *  Marceau (🇫🇷 France): World War I: The schooner was sunk in the Atlantic Ocean (46.25°N, -9.7°W) by SMU U-54 . Her crew survived.
 *  Paolina (🇺🇸 United States): World War I: The barque was sunk in the Atlantic Ocean 100 nmi north west of Ouessant, Finistère, France (48.61667°N, -8.75°W) by SMU UC-65 . Her crew survived.
 * Unione Republicaine (🇫🇷 France): World War I: The fishing vessel was sunk in the Atlantic Ocean 100 nmi west north west of Penmarc'h, Finistère (48.08333°N, -7.23333°W) by SMU U-90.

26 September

 *  Acorn ( undefined): World War I: The schooner was shelled and sunk in the English Channel 20 nmi south by east of Start Point, Devon by SMU UC-69 . Her crew survived.
 * Ciro ( undefined): World War I: The sailing vessel was scuttled in the Mediterranean Sea south of Sardinia by SMU UB-50.
 * SS Heraklios (1896) (🇬🇷 Greece): World War I: The cargo ship was sunk in the Mediterranean Sea off Cape Cherchell, Algeria (36.63333°N, 1.83333°W) by SMU U-63 (Germany) . Her crew survived.
 *  Jacqueline (🇫🇷 France): World War I: The barque was torpedoed and sunk in the Atlantic Ocean 250 nmi sout west of Ouessant, Finistère (46.35°N, -9.73333°W) by SMU U-101 with the loss of all 35 crew.
 * HMT Ocean Star : World War I: The naval trawler struck a mine and sank in the English Channel off the Nab Lightship ( undefined) with the loss of ten of her crew.
 * RUSSIAN DESTROYER Okhotnik : World War I: The General Kondratenko-class destroyer struck a mine and sank in the Iber Strait.
 * SS S.N.A. 3 (1915) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the North Sea 17 nmi off Flamborough Head, Yorkshire, United Kingdom (53.9°N, 0.11667°W) by SMU UB-30 . Her crew survived; they were rescued by SS Portaferry ( undefined).
 * SMU UC-33 : World War I: The Type UC II submarine was shelled, rammed and sunk in St. George's Channel (51.91667°N, -6.23333°W by the patrol boat PC-61 with the loss of 27 of her 28 crew.

27 September

 * HM CMB-8 : The Coastal Motor Boat was lost on this date.
 * Cydonia ( undefined): The collier was lost on this date.
 * Deux Jeannes (🇫🇷 France): World War I: The fishing vessel was sunk in the Atlantic Ocean 30 nmi south west of Ouessant, Finistère (48.1°N, -5.66667°W) by SMU U-90.
 * SS Greltoria (1917) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 3 nmi north west by north of Flamborough Head, Yorkshire by SMU UB-34 . Her crew survived.
 * Liberté (🇫🇷 France): World War I: The fishing vessel was sunk in the Atlantic Ocean 30 nmi south west of Ouessant (48.1°N, -5.66667°W) by SMU U-90.
 * Peuples Frères (🇫🇷 France): World War I: The fishing vessel was sunk in the Atlantic Ocean 30 nmi south west Ouessant (48.1°N, -5.66667°W) by SMU U-90.
 * SMU UC-6 : World War I: The Type UC I submarine struck a mine and sank in the North Sea off North Foreland, Kent, United Kingdom (51.5°N, 1.56667°W) with the loss of all sixteen crew.

29 September

 *  Bon Premier (🇫🇷 France): World War I: The barque was shelled and sunk in the Atlantic Ocean 200 nmi south west of Ouessant, Finistère (46.1°N, -11.41667°W) by SMU U-60 . Her crew survived.
 * SS Elmsgarth (1896) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 50 nmi north west of Tory Island, County Donegal by SMU U-61 . Her crew survived.
 *  Eugenie Fautrel (🇫🇷 France): World War I: The barque was shelled and sunk in the Atlantic Ocean 200 nmi south west of Ouessant (46.5°N, -9.98333°W) by SMU U-60 . Her crew were rescued by the fishing vessel Cygne (🇫🇷 France).
 * SS Kildonan (1898) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 2 nmi north north west of the Pendeen Lighthouse, Pembrokeshire (50.18333°N, -5.7°W) by SMU UB-35 with the loss of fourteen of her crew.
 *  Percy B. ( undefined): World War I: The schooner was shelled and sunk in the Atlantic Ocean 180 nmi north by west of Cape Villano, Spain by SMU U-60 . Her crew survived.
 * R 235 (🇫🇷 France): World War I: The fishing schooner was sunk in the Mediterranean Sea (34.63333°N, 34.71667°W) by SMU U-73 . Her crew survived.
 * SS Sanwen (1915) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea off Cape Béar, Spain (42.86667°N, 4.25°W) by SMU U-32 (Germany)  with the loss of two crew.
 * SS Swan River (1915) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 27 nmi west of Oran, Algeria (36.11667°N, -0.9°W) by SMU U-39 . Her crew survived.
 * SMU UC-55 : World War I: The Type UC II submarine was shelled, depth charged and sunk off the Shetland Islands, United Kingdom (60.03333°N, -1.03333°W) by HMS Sylvia (1897) and HMS Tirade (1917) (both ) with the loss of ten of her 27 crew.

30 September

 *  Amiral Troude (🇫🇷 France): World War I: The barque was torpedoed and sunk in the Atlantic Ocean 400 nmi off Penmarc'h, Finistère (46.66667°N, -15.5°W) by SMU UB-51 . Her crew survived.
 * HMT Charlsin : World War I: The naval trawler was scuttled in the Mediterranean Sea 8 nmi north of Mersa Matruh, Egypt by SMU UC-74 . Her crew survived.
 * SS Drake (1908) ( undefined): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 340 nmi west of Ouessant, Finistère (46.71667°N, -13.01667°W) by SMU U-90 . Her crew survived, but her captain was taken as a prisoner of war.
 * SS Heron (1889) ( undefined): World War I: The coaster was torpedoed and sunk in the Atlantic Ocean 300 nmi south west of Ouessant (46.45°N, -11.23333°W) by SMU U-90 with the loss of 22 crew.
 * SS Midlothian (1871) ( undefined): World War I: The cargo ship was shelled and sunk in the Mediterranean Sea 80 nmi south of Cape Greco, Cyprus by SMU U-73 . Her crew survived, but three of them were taken as prisoners of war.
 * Nicolosa (🇬🇷 Greece): World War I: The sailing vessel was sunk in the Mediterranean Sea off Cyprus by SMU U-73.

Unknown date

 * SMU U-66 : World War I: The Type U 66 submarine is believed to have struck a mine and sank in the North Sea off the Dogger Bank on or after 3 September with the loss of all 40 crew.
 * SMU UB-32 : World War I: The Type UB II submarine was lost after 17 September. She may have been bombed and sunk on 22 September by Royal Naval Air Service aircraft.