List of shipwrecks in April 1918

The list of shipwrecks in April 1918 includes ships sunk, foundered, grounded, or otherwise lost during April 1918.

1 April

 * SS Ardglass (1918) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 7 nmi north east of Larne, County Antrim by SMU UC-30 with the loss of seven of her crew.
 * HMS Falcon (1899) : The C-class destroyer collided with the trawler John Fitzgerald ( undefined) and sank in the North Sea off Bridlington, Yorkshire )54.12917°N, 0.36944°W).
 *  Lusitano (🇵🇹 Portugal): World War I: The barquentine was scuttled in the Atlantic Ocean off the Azores (38.83333°N, -18.4°W) by SMU U-155 . Her crew took to the lifeboats but were not rescued.

2 April

 * SS Meaford (1903) ( undefined): World War I: The cargo ship was sunk in the Atlantic Ocean by SMU U-53 with the loss of all hands.
 * SS Solway Queen (1883) ( undefined): World War I: The coaster was torpedoed and sunk in the Irish Sea 7 nmi off Black Head, Wigtownshire by SMU U-101 with the loss of eleven crew.

3 April

 * HMS E1 : World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 * HMS E9 : World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 *  Elsie Burdett ( undefined): World War I: The schooner was sunk in the Atlantic Ocean off the Canary Islands, Spain (44.63333°N, -24.46667°W) by SMU U-152 . Her six crew took to the lifeboat but were not rescued.
 * SS Sylvie (1917) (🇫🇷 France): World War I: The cargo ship was sunk in the Mediterranean Sea 120 nmi north east of Malta by SMU UC-54.

4 April

 *  Agatina ( undefined): World War I: the barquentine was shelled and sunk in the Mediterranean Sea off Sicily by SMU UC-25.
 * HMS Bittern (1897) : The collided with SS Kenilworth ( undefined) in the English Channel off the Isle of Portland, Dorset and sank with the loss of all 63 crew.
 * HMS C26 : World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 * HMS C27 : World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 * HMS E8 : World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 * HMT J&A : The naval trawler was lost on this date.
 * SS Liberia (1887) (🇫🇷 France): The cargo ship was sunk in the Gulf of Genoa 62 nmi south east of the Île d'Hyères (42.06667°N, 7.03333°W) by SMU UC-35 . Her crew survived.
 * SS Sincerita (1877) ( undefined): World War I: The cargo ship was sunk in the Mediterranean Sea (36.28333°N, 14.8°W) by SMU UB-52 . Her crew survived.

5 April

 * HMS C27 : World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 * HMS C35 : World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 *  Camelia ( undefined): World War I: The barque was shelled and sunk in the Mediterranean Sea off Cap Caccia (40.63333°N, 8.1°W) by SMU UC-35.
 * SS Cyrene (1888) ( undefined): World War I: The cargo ship was torpedoed and sunk in Caernarfon Bay 15 nmi north of Bardsey Island, Caernarfonshire by SMU UC-30 with the loss of 24 of her crew.

6 April

 * FRENCH Q-SHIP Madeleine III : World War I: The Q-ship was torpedoed and sunk in the Mediterranean Sea off the coast of Algeria (37.45°N, 9.88333°W) by SMU UB-50 with the loss of seventeen of her twenty crew. The survivors were taken as prisoners of war.
 * Madona Belle Grazie ( undefined): World War I: The sailing vessel was sunk in the Ionian Sea by SMU UC-52.
 * SS Ministre de Smet de Naeyer (🇧🇪 Belgium): World War I: The cargo ship struck a mine and sank in the North Sea 45 nmi north of the Dogger Bank Lightship ( undefined) with the loss of twelve of her 29 crew.
 * HMML 421 : The motor launch was lost on this date.
 * Sterne (🇳🇱 Netherlands): World War I: The sailing vessel was stopped in the North Sea 60 nmi off Jæren, Rogaland, Norway by SMU U-19 (Germany) . U-19 intended to sink her but lost sight of her. Sterne came ashore at Utsire, Rogaland and was a total loss.

7 April

 * SS Boscastle (1912) ( undefined): World War I: The collier was torpedoed and sunk in St. George's Channel 14 nmi north north west of Strumble Head, Pembrokeshire by SMU U-111 with the loss of eighteen crew.
 * Catriena (🇳🇱 Netherlands): World War I: The sailing vessel was sunk in the North Sea 58 nmi south west of Egersund, Rogaland, Norway (58.06667°N, 4.23333°W) by SMU UB-73 . Her crew survived.
 * SS Highland Brigade (1901) ( undefined): World War I: The cargo liner was sunk in the English Channel 6 nmi south by east of St. Catherine's Point (50.58333°N, -1.23333°W) by SMU UC-71 . Her crew survived.
 * SS Port Campbell (1904) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 115 nmi west south west of the Bishop Rock, Isles of Scilly by SMU U-53 . Her crew survived.
 * SS Rye (1914) ( undefined): World War I: The coaster was torpedoed and sunk in the English Channel 19 nmi north west by west of Cap d'Antifer, Seine-Maritime, France (49.95°N, -0.11667°W) by SMU UB-74 with the loss of four of her crew.
 * ITALIAN TANKER Sterope : World War I: The tanker was shelled and sunk in the Atlantic Ocean off the Azores, Portugal (38.73333°N, -18.15°W) by SMU U-155.
 *  Vera Cruz (🇺🇸 United States): The sailing ship was wrecked at Tampico, Tamaulipas, Mexico.

8 April

 * SS Bengali (1901) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 14 nmi off Alexandria, Egypt (31.35°N, 29.78333°W) by SMU UC-34 . Her crew survived.
 * HMS E19 : World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
 * SS Flanders (🇧🇪 Belgium): World War I: The cargo ship struck a mine and sank in the North Sea off the coast of the Netherlands. Her crew were rescued.
 * SS Nyassaland (1896) (🇳🇴 Norway): World War I: The coaster was sunk in the English Channel 18 nmi east of Start Point, Devon, United Kingdom by SMU UB-33 . Her crew survived.
 * Superb (🇳🇴 Norway): World War I: The sailing vessel was sunk in the North Sea 40 nmi south of Lindesnes, Vest-Agder by SMU U-90 . Her crew survived.
 * SS Tainui ( undefined): World War I: The cargo ship was torpedoed damaged in the Atlantic Ocean 60 nmi south west of the Isles of Scilly by SMU U-82 and was abandoned by her crew. She was beached at Falmouth, Cornwall but was later salvaged, repaired and returned to service.

9 April

 * HMT Annie Smith : The naval trawler was lost on this date.
 * SS Aveiro (1894) (🇵🇹 Portugal): World War I: The cargo ship was sunk in the Mediterranean Sea (36.4°N, 18.1°W) by SMU UB-53 . Her crew survived.
 * HMT Lord Hardinge : The naval trawler collided with another vessel and sank in the Irish Sea off the Daunt Lightship ( undefined).
 * SS President Leroy-Iallier (1881) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 15 nmi north west of Ouessant, Finistère (48.83333°N, -5.21667°W) by SMU UB-109 with the loss of 26 of her crew.
 * President Howard (🇱🇷 Liberia): World War I: The auxiliary sailing vessel was sunk in the Atlantic Ocean off Monrovia by SMU U-154.
 * SS Vasconia (1899) (🇳🇴 Norway): World War I: The cargo ship struck a mine and sank in the Mediterranean Sea north of Alexandria, Egypt with the loss of seven of her crew.

10 April

 * Asia ( undefined): The coaster foundered. Her crew were rescued by a Norwegian merchant vessel.
 * ITALIAN DESTROYER Benedetto Cairoli : The collided with ITALIAN DESTROYER Giacinto Carini and sank in the Ionian Sea.
 * SS Henley (1894) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 25 nmi south west of The Lizard, Cornwall (49.58333°N, -5.51667°W) by SMU UB-109 with the loss of six of her crew.
 * SS Westfield (1901) ( undefined): World War I: The cargo ship was sunk in the Atlantic Ocean 45 nmi south west by south of the Bishop Rock, Isles of Scilly (49.16667°N, -6.76667°W) by SMU U-82 . Her crew survived.

11 April

 * Carmela G ( undefined): World War I: The sailing vessel was sunk in the Mediterranean Sea west of Sicily by SMU UB-50.
 * SS Highland Prince (1901) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 36 nmi north east of Cape Bon, Algeria (37.45°N, 11.53333°W) by SMU UB-50 with the loss of three of her crew.
 * HMS King Alfred (1901) : World War I: The was torpedoed and damaged in the Atlantic Ocean 30 nmi north of Malin Head, County Donegal by SMU UB-86  with the loss of a crew member.
 * SS Kingstonian (1901) ( undefined): World War I: The cargo ship was torpedoed and damaged in the Mediterranean Sea off San Pietro Island, Italy (39.33333°N, 7.16667°W) by SMU UB-68 with the loss of a crew member. She was beached in Carloforte Bay but was again torpedoed and damaged on 29 April by SMU UB-48  and was a total loss.
 * USS Lakemoor (ID-2180) : World War I: The cargo ship was torpedoed and sunk in the Irish Sea 2.5 nmi off the Corsewall Lighthouse, Wigtownshire, United Kingdom by SMU UB-64 with the loss of 46 of her crew.
 * USS Mary B. Garner (SP-682) : The patrol vessel ran aground at Prime Hook, Delaware and was wrecked. She was later salvaged, repaired and returned to service.
 * SS Myrtle Branch (1899) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 9 nmi north east by north of Inishtrahull Island, County Donegal by SMU UB-73 with the loss of fifteen of her crew.
 * SMS Rheinland : The ran aground on Laagskar Island, Åland Islands, Sweden with the loss of two of her crew. She was refloated on 20 April and subsequently served as a barracks ship.
 * SMU UB-33 : World War I: The Type UB II submarine struck a mine and sank in the Strait of Dover (50.91667°N, 1.28333°W) with the loss of all 28 crew.

12 April

 * SS Autolycus (1917) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 38 nmi off Cape Palos, Spain (38.01667°N, 0.38333°W) by SMU U-34 (Germany) . Her crew survived.
 * HM CMB-18A : The Coastal Motor Boat was lost on this date.
 * HM CMB-33A : The Coastal Motor Boat was lost on this date.
 * SS Lonhelen (1911) ( undefined): World War I: The cargo ship struck a mine and sank in the North Sea south west of the Shipwash Lightship ( undefined). Her crew survived.
 * SS Luis (1916) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 3.5 nmi south south east of St. Catherine's Point, Isle of Wight by SMU UC-71 with the loss of four of her crew.
 * SS Luisa (1897) (🇪🇸 Spain): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 6 nmi west by south of the Pendeen Lighthouse, Cornwall, United Kingdom (50.11667°N, -5.81667°W) by SMU UB-74 . Her crew survived.
 * SS Moyune (1895) ( undefined): World War I: Convoy HE 9: The cargo ship was torpedoed and sunk in the Mediterranean sea off Cape Palos (37.43333°N, 0.1°W) by SMU U-34 (Germany) . Her crew survived.
 *  Njaal (Flag of Russian SFSR.svg Russia): World War I: The barque was sunk in the North Sea off Flekkefjord by SMU U-104.

13 April

 * SS Harewood (1913) ( undefined): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 380 nmi west by south of Lisbon, Portugal by SMU U-155 with the loss of two of her crew.
 * SS Provence (1884) (🇫🇷 France): World War I: The cargo ship was torpedoed and damaged in the Mediterranean Sea 1.5 nmi off the Cape Palamos Lighthouse, Spain (41.71667°N, 3.15°W) by SMU UB-68 . She was beached but was later refloated, repaired and returned to service.
 * Ruth ( undefined): World War I: The fishing smack was scuttled in the North Sea by a Kaiserliche Marine submarine.
 *  Wilson ( undefined): World War I: The schooner was scuttled in the Atlantic Ocean 10 nmi north west of the Smalls Lighthouse by SMU UB-109 . Her crew survived.

14 April

 * SS Chelford (1906) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea north west of Bardsey Island, Pembrokeshire (52.8°N, -5.06667°W) by SMU UB-73 . Her crew survived.
 * SS Maroc (1898) (🇫🇷 France): World War I: The cargo ship was sunk in the Atlantic Ocean 2 nmi off the Longships Lighthouse, Cornwall, United Kingdom by SMU UB-74.
 * SS Marstonmoor (1906) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 55 nmi north north east of Cape Wrath, Sutherland (59.56667°N, -4.75°W) by SMU U-107 . Her crew survived.
 * SS Santa Isabel (1914) ( undefined): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 15 nmi off the Cape Verde Islands, Portugal by SMU U-153 with the loss of a crew member.

15 April

 * SS Ailsa Craig (1906) ( undefined): World War I: The cargo ship was sunk in the English Channel 14 nmi west by north of Portland Bill, Dorset (50.5°N, -2.8°W) by SMU UB-80 . Her crew survived.
 * SS Pomeranian (1882) ( undefined): World War I: The ship was sunk in the English Channel 9 nmi off Portland Bill by SMU UC-77 with the loss of 55 lives.
 * SS Rostov (1867) : World War I: The transport ship was sunk in the Black Sea south of Sevastopol (44.56667°N, 34.33333°W) by SMU UC-23.

16 April

 * SS Florence H. (🇺🇸 United States): The cargo ship suffered an onboard explosion and sank at a French port with the loss of 41 of her 75 crew.
 * SS Hungerford (1913) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 9 nmi south south east of the Owers Lightship (50.55°N, -0.58333°W) by SMU UC-75 with the loss of eight of her crew.
 * SS Ladoga (1914) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 15 nmi south east of the South Arklow Lightship ( undefined) (52.55°N, -5.58333°W) by SMU UB-73 with the loss of 29 of her crew.
 * SS Lake Michigan (1902) ( undefined): World War I: The passenger ship was torpedoed and sunk in the Atlantic Ocean 93 nmi north by west of Eagle Island, County Mayo (55.5°N, -11.86667°W) by SMU U-100 ( with the loss of a crew member.
 * SS Lodaner (1905) ( undefined): World War I: The cargo ship was sunk in the Irish Sea south east of the South Arklow Lightship ( undefined) by SMU UB-73 with the loss of all 32 crew.
 * SS Nirpura (1916) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 110 nmi west north west of Cabo da Roca, Portugal (38.95°N, -11.91667°W) by SMU U-155 . Her crew survived.
 * SS Romania (1898) ( undefined): World War I: The cargo ship was sunk in the Adriatic Sea off Cape Linguetta, Albania (40.4°N, 19.23333°W) by SMU UC-22 . Her crew survived.
 * HMT Select : The naval trawler was lost on this date.
 * SMS Streiter : World War I: The collided with SS Petka ( Austria-Hungary) and sank in the Adriatic Sea off Lovran (45°N, 14.25°W). She was escorting a convoy at the time.
 * Widwud (Flag of Russian SFSR.svg Russia): World War I: The sailing vessel was sunk in the Atlantic Ocean north west of Ireland by SMU U-104.

17 April

 * SMU UB-82 : World War I: The Type UB III submarine was depth charged and sunk in the Irish Sea (55.21667°N, -5.91667°W) by two Royal Navy trawlers with the loss of all 32 crew.

18 April

 * SS Bamse (1875) ( undefined): World War I: The coaster was torpedoed and sunk in the English Channel 15 nmi west by north of Portland Bill, Dorset by SMU UB-80 with the loss of four of her crew.
 * SS Dalegarth Force (1914) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 12 nmi south west of Hartland Point, Devon (50.85°N, -4.7°W) by SMU UB-73 with the loss of five crew.
 * FRENCH DESTROYER Faulx : The was rammed and sunk in the Strait of Otranto by FRENCH DESTROYER Mangani.
 * SS Gregynog (1899) ( undefined): World War I: The collier was torpedoed and sunk in the English Channel 16 nmi south west of Hartland Point (50.78333°N, -4.73333°W) by SMU UB-86 with the loss of three of her crew.
 * SS Pentyrch (1899) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 5 nmi west north west of the Brighton Lightship ( undefined) by SMU UB-40 with the loss of a crew member.
 * SS Runswick (1904) ( undefined): World War I: The cargo ship was torpedoed and damaged in the Atlantic Ocean 3 nmi north of Trevose Head, Cornwall (50.55°N, -5.05°W) by SMU UB-109 . She was beached but was declared a total loss. Her crew survived.

19 April

 * SS Alice Taylor ( undefined): The coaster foundered on this date. Her crew were rescued.
 * SS Elka (1881) (🇬🇷 Greece): World War I: Convoy GaG16: The cargo ship was torpedoed and sunk in the Mediterranean Sea 50 nmi off Cape Gati, Spain by SMU U-34 (Germany) . Her crew survived.
 * SS Lord Charlemont (1886) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 22 nmi north of the Isla de Alborán, Morocco (36.25°N, -3.06667°W) by SMU U-34 (Germany) with the loss of eight crew.
 * FRENCH TRAWLER Salambo : World War I: The naval trawler was torpedoed and sunk in the Ionian Sea (38.5°N, 18.1°W) by SMU U-38 . Her crew survived.
 * SMU UB-78 : World War I: The Type UB III submarine struck a mine and sank in the Strait of Dover (51.01667°N, 1.28333°W) with the loss of all 35 crew.
 * SS War Helmet ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 3 nmi east by north of the Owers Lightship ( undefined) by SMU UC-75 . Her crew survived.

20 April

 * SS Florrieston (1901) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 6 nmi east of South Stack, Anglesey by SMU U-91 with the loss of nineteen of her crew.
 * SS Lowther Range (1906) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 20 nmi west by north of South Stack (53.3°N, -5.16667°W) by SMU U-91 . Her crew survived.
 * HMT Numitor : World War I: The naval trawler struck a mine and sank in the North Sea off Orfordness, Suffolk (52.11667°N, 1.75°W) with the loss of five of her crew.

21 April

 * SS Bellview (1894) ( undefined): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 16 nmi east north east of Cape Bon, Tunisia (37.21667°N, 11.35°W) by SMU U-32 (Germany) . Her crew survived.
 * Delta A (🇧🇪 Belgium): World War I: The trawler was stopped and sunk in the Atlantic Ocean 18 nmi south of St. Kilda, Inverness-shire, United Kingdom by SMU U-19 (Germany).
 * SS Landonia (1917) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 27 nmi north west by west of Strumble Head, Pembrokeshire by SMU U-91 with the loss of 21 of her crew. One of the survivors was taken as a prisoner of war.
 * SS Normandiet (1902) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 34 nmi south west by west of the Calf of Man, Isle of Man by SMU U-91 with the loss of nineteen of her crew.
 * SMU UB-71 : World War I: The Type UB III submarine was depth charged and sunk in the Strait of Gibraltar (35.63333°N, -5.3°W) by HMML 413 with the loss of all 32 crew.
 * SS Westergate (1881) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 22 nmi east of Start Point, Devon by SMU UB-80 with the loss of 24 of her crew.

22 April

 * ST Baron Herries : World War I: The naval tug was torpedoed and sunk in the Atlantic Ocean 43 nmi north by west of the Bishop Rock, Isles of Scilly (50.45°N, -7.1°W) by SMU U-91 with the loss of three of her crew. One of the survivors was taken as a prisoner of war.
 * SS Dronning Maud (1917) ( undefined): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 65 nmi north north east of Cape Sigli, Algeria (38°N, 4.93333°W) by SMU U-34 (Germany) with the loss of a crew member.
 * SS Eric Calvert (1889) ( undefined): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 4 nmi south south west of St Anthony Head, Cornwall 50.075°N, -5.02917°W) by SMU UB-103 with the loss of two of her crew.
 * USS Fenimore (ID-2681) : The cargo ship was destroyed by fire in New York Harbor.
 * SS Fern (1900) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 5 nmi east of the Kish Lightship ( undefined) by SMU U-104 with the loss of thirteen crew.
 * Kheda Moulekar (🇫🇷 France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32.13333°N, 32.83333°W) by SMU UB-53.
 * Marshalla ( undefined): World War I: The sailing vessel was shelled sunk in the Mediterranean Sea 50 nmi north of Port Said, Egypt (32.18333°N, 32.65°W) by SMU UB-53.
 * HMT Pursuit : The naval trawler was lost on this date.
 * Sadika (🇫🇷 France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32.21667°N, 32.66667°W) by SMU UB-53.
 * SMU UB-55 : World War I: The Type UB III submarine struck a mine and sank in the Strait of Dover (51.01667°N, 1.33333°W) with the loss of 23 of her 29 crew.
 * SS Welbeck Hall (1914) ( undefined): World War I: The ship was torpedoed and sunk in the Mediterranean Sea 75 nmi north east by north of Port Said by SMU UB-53 with the loss of four of her crew.

23 April

 * HMS Brilliant (1891) : World War I: First Ostend Raid: The was scuttled as a blockship at Ostend, West Flanders, Belgium.
 * HMS C3 : World War I: Zeebrugge Raid: The C-class submarine was scuttled at Zeebrugge, West Flanders.
 * Frances ( undefined): World War I: The ketch was scuttled in the Atlantic Ocean (46.55°N, -12.08333°W) by SMU U-155 with the loss of two of her crew.
 * HMS Intrepid (1892) : World War I: Zeebrugge Raid: The destroyer was scuttled at Zeebrugge in an attempt to block the entrance to the Bruges Canal.
 * HMS Iphigenia (1891) : World War I: Zeebrugge Raid: The destroyer was scuttled at Zeebrugge in an attempt to block the entrance to the Bruges Canal.
 * SS Laurium (1896) ( undefined): World War I: The coaster struck a mine and sank in the North Sea off the Inner Dowsing Lightship ( undefined) with the loss of a crew member.
 * HMML 110 : The motor launch was lost on this date.
 * HMML 424 : The motor launch was lost on this date.
 * HMS North Star (1916) : World War I: Zeebrugge Raid: The was shelled and sunk at Zeebrugge by Germ shore-based artillery.
 * Peregrine ( undefined): World War I: The trawler was shelled and sunk in Yell Sound by SMU U-19 (Germany) . Her crew survived.
 * HMT Plethos : World War I: The naval trawler struck a mine and sank in the North Sea 40 nmi east north east of Montrose, Forfarshire with the loss of four of her crew.
 * Restaurado (🇵🇹 Portugal): World War I: The sailing vessel was sunk in the Atlantic Ocean off the coast of Portugal by SMU UB-105.
 * HMS Sirius (1892) : World War I: First Ostend Raid: The was scuttled as a blockship at Ostend.
 * HMS Thetis (1890) : World War I: Zeebrugge Raid: The  was scuttled at Zeebrugge in an attempt to block the entrance to the Bruges Canal.
 * Tyne Wave ( undefined): World War I: The trawler was shelled and sunk in the North Sea 16 nmi north east of Ronas Voe, Shetland Islands by SMU U-19 (Germany) . Her crew survived.

24 April

 * SS Agnete ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 4 nmi south by west of Start Point, Devon by a Kaiserliche Marine submarine with teh loss of twelve of her crew.
 * Leonor (🇵🇹 Portugal): World War I: The trawler was scuttled in the Atlantic Ocean off the coast of Portugal by SMU UB-105.
 * Mabrouska (🇫🇷 France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32.73333°N, 32.66667°W) by SMU UB-53.

25 April

 * HMS Cowslip (1917) : World War I: The was sunk in the Atlantic Ocean off Cape Spartel, Morocco by SMU UB-105  with the loss of six of her 93 crew.
 * Joseph (🇫🇷 France): World War I: The sailing vessel was sunk in the English Channel off Cherbourg, Seine-Maritime by SMU UB-31.
 * SS Sevilla (1913) (🇳🇴 Norway): World War I: The cargo ship was sunk in the English Channel 3 nmi north west of Berry Head, Devon, United Kingdom (50.4°N, -3.38333°W) by SMU UB-80 with the loss of a crew member.
 * SS Sote (1883) (🇸🇪 Sweden): World War I: The cargo ship was torpedoed and sunk in the North Sea off Flamborough Head, East Riding of Yorkshire, United Kingdom by SMU UC-64 with the loss of a crew member.
 * HMS St. Seiriol : World War I: The auxiliary minesweeper struck a mine and sank in the North Sea off the Shipwash Lightship ( undefined) with the loss of twelve of her crew.
 * SMU U-104 : World War I: The Type U 57 submarine was depth charged and sunk in St. George's Channel (51.98333°N, -6.43333°W) by USS Cushing (DD-55) and HMS Jessamine  with the loss of 41 of her 42 crew.
 * HMS Willow Branch : World War I: The Q-ship was sunk in the Atlantic Ocean off Cabo Blanco, Mauritania (21°N, -17.93333°W) by SMU U-153 and SMU U-154 (both ) with the loss of 58 of her crew.
 * HM TORPEDO BOAT 90 : The torpedo boat capsized and sank off Gibraltar.

26 April

 *  Angelina di Paola ( undefined): World War I: The brig was sunk in the Mediterranean Sea north of Cape San Vito, Sicily by SMU UB-68.
 *  Ethel ( undefined): World War I: The schooner was shelled and sunk in the Irish Sea 19 nmi north by east of the Smalls Lighthouse by SMU U-91 . Her crew survived.
 * SS Leopold d'Or (1917) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the Tyrrhenian Sea off San Pietro Island, Italy (39.91667°N, 7.03333°W) by SMU UB-48.
 * SS Llyngwair (1913) ( undefined): World War I: The collier was torpedoed and sunk in the North Sea 5 nmi south south east of Seaham Harbour, County Durham by SMU UC-64 with the loss of eight of her crew.

27 April

 * Azizeh (🇫🇷 France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32.11667°N, 32.53333°W) by SMU UB-53.
 * SS Gresham (1905) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 18 nmi north west by north of Strumble Head, Pembrokeshire (52.23333°N, -5.08333°W) by SMU U-91 . Her crew survived.
 * Nemaat Kheda (🇫🇷 France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32.11667°N, 32.53333°W) by SMU UB-53 . Her crew survived.
 * SS Romany (1902) ( undefined): World War I: The tanker was torpedoed and sunk in the Mediterranean Sea 47 nmi west south west of Cape Spartivento, Italy by SMU UB-48 . Her crew survived.
 * Walpas (Flag of Russian SFSR.svg Russia): World War I: The sailing vessel was sunk in the Irish Sea 15 nmi west by nort of Bardsey Island, Pembrokeshire by SMU U-91.

28 April

 * HM CMB-39B : The Coastal Motor Boat was lost on this date.
 * HMS Dalkeith : World War I: The tug was torpedoed and sunk in Carloforte Bay, Sardinia, Italy by SMU UB-48 with the loss of nine of her crew.
 * SS Damao (1911) (🇵🇹 Portugal): World War I: The cargo ship was sunk in St. George's Channel 12 nmi west of Bardsey Island, Pembrokeshire, United Kingdom by SMU U-91.
 * SS Elba (1899) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 6 nmi north west of the Pendeen Lighthouse (50.21667°N, -5.8°W) by SMU UB-103 with the loss of ten of her crew.
 * HMT Emley : World War I: The naval trawler was sunk in the Firth of Forth south of the Isle of May, Fife by SMU UC-40 with the loss of eight of her crew.
 * SS Kingstonian ( undefined): World War I: the cargo ship was torpedoed and sunk in Carloforte Bay by SMU UB-48 with the loss of a crew member.
 * ST Moose ( undefined): World War I: The tug was torpedoed and sunk in Carloforte Bay by SMU UB-48.
 * SS Oronsa (1906) ( undefined): World War I: The passenger ship was torpedoed and sunk in St. George's Channel 12 nmi west of Bardsey Island by SMU U-91 with the loss of three of her crew.
 * SS Poitiers (1917) (🇫🇷 France): World War I: The cargo ship was sunk in the Atlantic Ocean 4 nmi south west of Hartland Point, Devon, United Kingdom by SMU U-60.
 * SS Rimfakse (1909) (🇳🇴 Norway): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 10 nmi south west of Hartland Point (50.9°N, -4.58333°W) by SMU U-60 . Her crew survived.
 * SS Upcerne (1906) ( undefined): World War I: The cargo ship was torpedoed and sunk in the North Sea 4 nmi south east by east of Coquet Island, Northumberland by SMU UC-40 with the loss of sixteen of her crew.
 * SS Verdun (1902) (🇫🇷 France): World War I: The cargo ship was sunk in the Gulf of Gabès 37 nmi east of Kerkennah, Tunisia (34.81667°N, 11.86667°W) by SMU UC-20.

29 April

 * SS Australier (1906) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 6 nmi south west by south of Dungeness, Kent (50.86667°N, 0.96667°W) by SMU UB-57 with the loss of five of her crew.
 * SS Broderick (1890) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 7 nmi south south east of Hastings, East Sussex by SMU UB-57 . Her crew survived.
 *  Christiana Davis ( undefined): World War I: The schooner was shelled and sunk in the Atlantic Ocean 8 nmi south east by south of the Tuskar Rock, Ireland by SMU U-105 . Her crew survived.
 *  City of Pensacola (🇺🇸 United States): World War I: The auxiliary four-masted schooner was sunk in the Mediterranean Sea off Garrucha, Almería, Spain (38.96667°N, 4.35°W) by SMU UB-105 . Her crew survived.
 * HMS Dalkeith : World War I: The naval tug was sunk in the Mediterranean Sea off San Pietro Island, Italy by SMU UB-48 with the loss of nine of her crew.
 * SS Ellis Sayer ( undefined): The collier was lost on this date.
 * SS Frogner (1907) (🇳🇴 Norway): World War I: The cargo ship was sunk in the English Channel 3 nmi off Portland Bill, Dorset, United Kingdom by SMU UC-17 . Her crew survived.
 * Johnny Toole ( undefined): World War I: The ketch was shelled and sunk in the Atlantic Ocean 3 nmi south of the Tuskar Rock by SMU U-105 . Her crew survived.
 * SS Kut Sang (1905) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 40 nmi east south east of Cape Palos, Spain by SMU UB-105 with the loss of 59 of her crew.
 * SS La Somme (1882) (🇫🇷 France): World War I: The cargo ship was sunk in the English Channel 5 nmi west south west of Dungeness (50.86667°N, 0.85°W) by SMU UB-57 with the loss of a crew member.
 * Maria (🇬🇷 Greece): World War I: The vessel was sunk in the Mediterranean Sea (35.63333°N, 13.33333°W) by SMU U-27 (Austria-Hungary) . Her crew survived.
 * FRENCH SUBMARINE Prarial : The was run down and sunk in the English Channel off Le Havre, Seine Maritime by SS Tropic ( undefined) with the loss of nineteen of her 26 crew.
 * SS Saint Chamond (1913) (🇫🇷 France): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 14 nmi north of St. Ives Head, Cornwall, United Kingdom (50.25°N, -5.5°W) by SMU U-60 . Her crew survived.

30 April

 * SS Conway (1901) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 38 nmi south of Cape Palos, Murcia, Spain (37.16667°N, -0.46667°W) by SMU UB-105 . Her crew survived.
 * SS Ella Sayer (1898) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 15 nmi east by north of the Royal Sovereign Lightship (50.81667°N, 0.8°W) by SMU UB-57 with the loss of two of her crew.
 * SS Isleworth (1896) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 3 nmi south west of Ventnor, Isle of Wight by SMU UC-17 with the loss of 29 of her crew.
 * SS Kafue (1913) ( undefined): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 11 nmi south west of the Mull of Galloway, Wigtownshire by SMU U-86 with the loss of a crew member.
 * Kalliope ( undefined): World War I: The sailing vessel was sunk in the Mediterranean Sea 45 nmi off Alexandria, Egypt by SMU UC-74.
 * SS Kempock (1866) ( undefined): World War I: The coaster was shelled and sunk in the Irish Sea 6.5 nmi south east by south of the Copeland Islands by SMU U-86 . Her crew survived.
 * SMU UB-85 : World War I: The Type UB III submarine foundered in the Irish Sea off Belfast, County Antrim, United Kingdom. All 34 crew were rescued by HMS Coreopsis (1917).
 * SS Umba (1903) ( undefined): World War I: The cargo ship was torpedoed and sunk in the English Channel 1 nmi south of the Royal Sovereign Lightship ( undefined) by SMU UB-57 with the loss of twenty of her crew.

Unknown date

 * SS Cicero ( undefined): World War I: The cargo ship was scuttled in the Baltic Sea to avoid capture by the Germans.
 * SS Emilie ( undefined): World War I: The cargo ship was scuttled in the Baltic Sea to avoid capture by the Germans.
 *  Michelet: (🇫🇷 France): World War I: The barque was sunk in the Atlantic Ocean off the west coast of Africa on or about 25 April by SMU U-154 with the loss of all 28 crew.
 * SS Obsidian ( undefined): World War I: The cargo ship was scuttled in the Baltic Sea to avoid capture by the Germans.
 * FRENCH SUBMARINE Prarial : The submarine collided with a merchant vessel and sank with some loss of life.
 * SMU UC-79 : World War I: The Type UC II submarine struck a mine and sank in the English Channel off Cap Gris Nez, Pas-de-Calais, France during the first week of April with the loss of all 30 crew.