List of shipwrecks in April 1918

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

April 1918
Mon	Tue	Wed	Thu	Fri	Sat	Sun
Unknown date					1	2
3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	19	20	21	22	23
24	25	26	27	28	29	30

1 April

• Ardglass (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 7 nautical miles (13 km) north east of Larne, County Antrim by SM UC-30 (Kaiserliche Marine) with the loss of seven of her crew.
• HMS Falcon (Royal Navy): The C-class destroyer collided with the trawler John Fitzgerald (United Kingdom of Great Britain and Ireland) and sank in the North Sea off Bridlington, Yorkshire )54°07′45″N 0°22′10″E).
• Lusitano (Portugal): World War I: The barquentine was scuttled in the Atlantic Ocean off the Azores (38°50′N 18°24′W) by SM U-155 (Kaiserliche Marine). Her crew took to the lifeboats but were not rescued.

2 April

• Meaford (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was sunk in the Atlantic Ocean by SM U-53 (Kaiserliche Marine) with the loss of all hands.
• Solway Queen (United Kingdom of Great Britain and Ireland): World War I: The coaster was torpedoed and sunk in the Irish Sea 7 nautical miles (13 km) off Black Head, Wigtownshire by SM U-101 (Kaiserliche Marine) with the loss of eleven crew.

3 April

• HMS E1 (Royal Navy): World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• HMS E9 (Royal Navy): World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• Elsie Burdett (United Kingdom of Great Britain and Ireland): World War I: The schooner was sunk in the Atlantic Ocean off the Canary Islands, Spain (44°38′N 24°28′W) by SM U-152 (Kaiserliche Marine). Her six crew took to the lifeboat but were not rescued.
• Sylvie (France): World War I: The cargo ship was sunk in the Mediterranean Sea 120 nautical miles (220 km) north east of Malta by SM UC-54 (Kaiserliche Marine).

4 April

• Agatina (Kingdom of Italy): World War I: the barquentine was shelled and sunk in the Mediterranean Sea off Sicily by SM UC-25 (Kaiserliche Marine).
• HMS Bittern (Royal Navy): The Avon-class destroyer collided with Kenilworth (United Kingdom of Great Britain and Ireland) in the English Channel off the Isle of Portland, Dorset and sank with the loss of all 63 crew.
• HMS C26 (Royal Navy): World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• HMS C27 (Royal Navy): World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• HMS E8 (Royal Navy): World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• HMT J&A (Royal Navy): The naval trawler was lost on this date.
• Liberia (France): The cargo ship was sunk in the Gulf of Genoa 62 nautical miles (115 km) south east of the Île d'Hyères (42°04′N 7°02′E) by SM UC-35 (Kaiserliche Marine). Her crew survived.
• Sincerita (Kingdom of Italy): World War I: The cargo ship was sunk in the Mediterranean Sea (36°17′N 14°48′E) by SM UB-52 (Kaiserliche Marine). Her crew survived.

5 April

• HMS C27 (Royal Navy): World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• HMS C35 (Royal Navy): World War I: The C-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• Camelia (Kingdom of Italy): World War I: The barque was shelled and sunk in the Mediterranean Sea off Cap Caccia (40°38′N 8°06′E) by SM UC-35 (Kaiserliche Marine).
• Cyrene (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in Caernarfon Bay 15 nautical miles (28 km) north of Bardsey Island, Caernarfonshire by SM UC-30 (Kaiserliche Marine) with the loss of 24 of her crew.

6 April

• Madeleine III (French Navy): World War I: The Q-ship was torpedoed and sunk in the Mediterranean Sea off the coast of Algeria (37°27′N 9°53′E) by SM UB-50 (Kaiserliche Marine) with the loss of seventeen of her twenty crew. The survivors were taken as prisoners of war.
• Madona Belle Grazie (Kingdom of Italy): World War I: The sailing vessel was sunk in the Ionian Sea by SM UC-52 (Kaiserliche Marine).
• Ministre de Smet de Naeyer (Belgium): World War I: The cargo ship struck a mine and sank in the North Sea 45 nautical miles (83 km) north of the Dogger Bank Lightship (United Kingdom of Great Britain and Ireland) with the loss of twelve of her 29 crew.
• HMML 421 (Royal Navy): The motor launch was lost on this date.
• Sterne (Netherlands): World War I: The sailing vessel was stopped in the North Sea 60 nautical miles (110 km) off Jæren, Rogaland, Norway by SM U-19 (Kaiserliche Marine). U-19 intended to sink her but lost sight of her. Sterne came ashore at Utsire, Rogaland and was a total loss.

7 April

• Boscastle (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in St. George's Channel 14 nautical miles (26 km) north north west of Strumble Head, Pembrokeshire by SM U-111 (Kaiserliche Marine) with the loss of eighteen crew.
• Catriena (Netherlands): World War I: The sailing vessel was sunk in the North Sea 58 nautical miles (107 km) south west of Egersund, Rogaland, Norway (58°04′N 4°14′E) by SM UB-73 (Kaiserliche Marine). Her crew survived.
• Highland Brigade (United Kingdom of Great Britain and Ireland): World War I: The cargo liner was sunk in the English Channel 6 nautical miles (11 km) south by east of St. Catherine's Point (50°35′N 1°14′W) by SM UC-71 (Kaiserliche Marine). Her crew survived.
• Port Campbell (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 115 nautical miles (213 km) west south west of the Bishop Rock, Isles of Scilly by SM U-53 (Kaiserliche Marine). Her crew survived.
• Rye (United Kingdom of Great Britain and Ireland): World War I: The coaster was torpedoed and sunk in the English Channel 19 nautical miles (35 km) north west by west of Cap d'Antifer, Seine-Maritime, France (49°57′N 0°07′W) by SM UB-74 (Kaiserliche Marine) with the loss of four of her crew.
• Sterope (Regia Marina): World War I: The tanker was shelled and sunk in the Atlantic Ocean off the Azores, Portugal (38°44′N 18°09′W) by SM U-155 (Kaiserliche Marine).
• Vera Cruz (United States): The sailing ship was wrecked at Tampico, Tamaulipas, Mexico.

8 April

• Bengali (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 14 nautical miles (26 km) off Alexandria, Egypt (31°21′N 29°47′E) by SM UC-34 (Kaiserliche Marine). Her crew survived.
• HMS E19 (Royal Navy): World War I: The E-class submarine was scuttled in the Gulf of Finland off the Harmaja Lighthouse.
• 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.
• Nyassaland (Norway): World War I: The coaster was sunk in the English Channel 18 nautical miles (33 km) east of Start Point, Devon, United Kingdom by SM UB-33 (Kaiserliche Marine). Her crew survived.
• Superb (Norway): World War I: The sailing vessel was sunk in the North Sea 40 nautical miles (74 km) south of Lindesnes, Vest-Agder by SM U-90 (Kaiserliche Marine). Her crew survived.
• Tainui (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed damaged in the Atlantic Ocean 60 nautical miles (110 km) south west of the Isles of Scilly by SM U-82 (Kaiserliche Marine) 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 (Royal Navy): The naval trawler was lost on this date.
• Aveiro (Portugal): World War I: The cargo ship was sunk in the Mediterranean Sea (36°24′N 18°06′E) by SM UB-53 (Kaiserliche Marine). Her crew survived.
• HMT Lord Hardinge (Royal Navy): The naval trawler collided with another vessel and sank in the Irish Sea off the Daunt Lightship (United Kingdom of Great Britain and Ireland).
• President Leroy-Iallier (France): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 15 nautical miles (28 km) north west of Ouessant, Finistère (48°50′N 5°13′W) by SM UB-109 (Kaiserliche Marine) 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 SM U-154 (Kaiserliche Marine).
• Vasconia (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 (United Kingdom of Great Britain and Ireland): The coaster foundered. Her crew were rescued by a Norwegian merchant vessel.
• Benedetto Cairoli (Regia Marina): The La Masa-class destroyer collided with Giacinto Carini and sank in the Ionian Sea.
• Henley (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 25 nautical miles (46 km) south west of The Lizard, Cornwall (49°35′N 5°31′W) by SM UB-109 (Kaiserliche Marine) with the loss of six of her crew.
• Westfield (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was sunk in the Atlantic Ocean 45 nautical miles (83 km) south west by south of the Bishop Rock, Isles of Scilly (49°10′N 6°46′W) by SM U-82 (Kaiserliche Marine). Her crew survived.

11 April

• Carmela G (Kingdom of Italy): World War I: The sailing vessel was sunk in the Mediterranean Sea west of Sicily by SM UB-50 (Kaiserliche Marine).
• Highland Prince (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 36 nautical miles (67 km) north east of Cape Bon, Algeria (37°27′N 11°32′E) by SM UB-50 (Kaiserliche Marine) with the loss of three of her crew.
• HMS King Alfred (Royal Navy): World War I: The Drake-class cruiser was torpedoed and damaged in the Atlantic Ocean 30 nautical miles (56 km) north of Malin Head, County Donegal by SM UB-86 (Kaiserliche Marine) with the loss of a crew member.
• Kingstonian (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and damaged in the Mediterranean Sea off San Pietro Island, Italy (39°20′N 7°10′E) by SM UB-68 (Kaiserliche Marine) with the loss of a crew member. She was beached in Carloforte Bay but was again torpedoed and damaged on 29 April by SM UB-48 (Kaiserliche Marine) and was a total loss.
• USS Lakemoor (United States Navy): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 2.5 nautical miles (4.6 km) off the Corsewall Lighthouse, Wigtownshire, United Kingdom by SM UB-64 (Kaiserliche Marine) with the loss of 46 of her crew.
• USS Mary B. Garner (United States Navy): The patrol vessel ran aground at Prime Hook, Delaware and was wrecked. She was later salvaged, repaired and returned to service.
• Myrtle Branch (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 9 nautical miles (17 km) north east by north of Inishtrahull Island, County Donegal by SM UB-73 (Kaiserliche Marine) with the loss of fifteen of her crew.
• SMS Rheinland (Kaiserliche Marine): The Nassau-class battleship 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.
• SM UB-33 (Kaiserliche Marine): World War I: The Type UB II submarine struck a mine and sank in the Strait of Dover (50°55′N 1°17′E) with the loss of all 28 crew.

12 April

• Autolycus (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 38 nautical miles (70 km) off Cape Palos, Spain (38°01′N 0°23′E) by SM U-34 (Kaiserliche Marine). Her crew survived.
• HM CMB-18A (Royal Navy): The Coastal Motor Boat was lost on this date.
• HM CMB-33A (Royal Navy): The Coastal Motor Boat was lost on this date.
• Lonhelen (United Kingdom of Great Britain and Ireland): World War I: The cargo ship struck a mine and sank in the North Sea south west of the Shipwash Lightship (United Kingdom of Great Britain and Ireland). Her crew survived.
• Luis (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 3.5 nautical miles (6.5 km) south south east of St. Catherine's Point, Isle of Wight by SM UC-71 (Kaiserliche Marine) with the loss of four of her crew.
• Luisa (Spain): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 6 nautical miles (11 km) west by south of the Pendeen Lighthouse, Cornwall, United Kingdom (50°07′N 5°49′W) by SM UB-74 (Kaiserliche Marine). Her crew survived.
• Moyune (United Kingdom of Great Britain and Ireland): World War I: Convoy HE 9: The cargo ship was torpedoed and sunk in the Mediterranean sea off Cape Palos (37°26′N 0°06′E) by SM U-34 (Kaiserliche Marine). Her crew survived.
• Njaal ( Russia): World War I: The barque was sunk in the North Sea off Flekkefjord by SM U-104 (Kaiserliche Marine).

13 April

• Harewood (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 380 nautical miles (700 km) west by south of Lisbon, Portugal by SM U-155 (Kaiserliche Marine) with the loss of two of her crew.
• Provence (France): World War I: The cargo ship was torpedoed and damaged in the Mediterranean Sea 1.5 nautical miles (2.8 km) off the Cape Palamos Lighthouse, Spain (41°43′N 3°09′E) by SM UB-68 (Kaiserliche Marine). She was beached but was later refloated, repaired and returned to service.
• Ruth (United Kingdom of Great Britain and Ireland): World War I: The fishing smack was scuttled in the North Sea by a Kaiserliche Marine submarine.
• Wilson (United Kingdom of Great Britain and Ireland): World War I: The schooner was scuttled in the Atlantic Ocean 10 nautical miles (19 km) north west of the Smalls Lighthouse by SM UB-109 (Kaiserliche Marine). Her crew survived.

14 April

• Chelford (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea north west of Bardsey Island, Pembrokeshire (52°48′N 5°04′W) by SM UB-73 (Kaiserliche Marine). Her crew survived.
• Maroc (France): World War I: The cargo ship was sunk in the Atlantic Ocean 2 nautical miles (3.7 km) off the Longships Lighthouse, Cornwall, United Kingdom by SM UB-74 (Kaiserliche Marine).
• Marstonmoor (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 55 nautical miles (102 km) north north east of Cape Wrath, Sutherland (59°34′N 4°45′W) by SM U-107 (Kaiserliche Marine). Her crew survived.
• Santa Isabel (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 15 nautical miles (28 km) off the Cape Verde Islands, Portugal by SM U-153 (Kaiserliche Marine) with the loss of a crew member.

15 April

• Ailsa Craig (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was sunk in the English Channel 14 nautical miles (26 km) west by north of Portland Bill, Dorset (50°30′N 2°48′W) by SM UB-80 (Kaiserliche Marine). Her crew survived.
• Pomeranian (United Kingdom of Great Britain and Ireland): World War I: The ship was sunk in the English Channel 9 nautical miles (17 km) off Portland Bill by SM UC-77 (Kaiserliche Marine) with the loss of 55 lives.
• Rostov (Imperial Russian Navy): World War I: The transport ship was sunk in the Black Sea south of Sevastopol (44°34′N 34°20′E) by SM UC-23 (Kaiserliche Marine).

16 April

• 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.
• Hungerford (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 9 nautical miles (17 km) south south east of the Owers Lightship (50°33′N 0°35′W) by SM UC-75 (Kaiserliche Marine) with the loss of eight of her crew.
• Ladoga (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 15 nautical miles (28 km) south east of the South Arklow Lightship (United Kingdom of Great Britain and Ireland) (52°33′N 5°35′W) by SM UB-73 (Kaiserliche Marine) with the loss of 29 of her crew.
• Lake Michigan (United Kingdom of Great Britain and Ireland): World War I: The passenger ship was torpedoed and sunk in the Atlantic Ocean 93 nautical miles (172 km) north by west of Eagle Island, County Mayo (55°30′N 11°52′W) by SM U-100 (Kaiserliche Marine with the loss of a crew member.
• Lodaner (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was sunk in the Irish Sea south east of the South Arklow Lightship (United Kingdom of Great Britain and Ireland) by SM UB-73 (Kaiserliche Marine) with the loss of all 32 crew.
• Nirpura (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 110 nautical miles (200 km) west north west of Cabo da Roca, Portugal (38°57′N 11°55′W) by SM U-155 (Kaiserliche Marine). Her crew survived.
• Romania (Kingdom of Italy): World War I: The cargo ship was sunk in the Adriatic Sea off Cape Linguetta, Albania (40°24′N 19°14′E) by SM UC-22 (Kaiserliche Marine). Her crew survived.
• HMT Select (Royal Navy): The naval trawler was lost on this date.
• SMS Streiter (Austro-Hungarian Navy): World War I: The Huszar-class destroyer collided with Petka (Austria-Hungary) and sank in the Adriatic Sea off Lovran (45°00′N 14°15′E). She was escorting a convoy at the time.
• Widwud ( Russia): World War I: The sailing vessel was sunk in the Atlantic Ocean north west of Ireland by SM U-104 (Kaiserliche Marine).

17 April

• SM UB-82 (Kaiserliche Marine): World War I: The Type UB III submarine was depth charged and sunk in the Irish Sea (55°13′N 5°55′W) by two Royal Navy trawlers with the loss of all 32 crew.

18 April

• Bamse (United Kingdom of Great Britain and Ireland): World War I: The coaster was torpedoed and sunk in the English Channel 15 nautical miles (28 km) west by north of Portland Bill, Dorset by SM UB-80 (Kaiserliche Marine) with the loss of four of her crew.
• Dalegarth Force (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 12 nautical miles (22 km) south west of Hartland Point, Devon (50°51′N 4°42′W) by SM UB-73 (Kaiserliche Marine) with the loss of five crew.
• Faulx (French Navy): The Bouclier-class destroyer was rammed and sunk in the Strait of Otranto by Mangani (French Navy).
• Gregynog (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the English Channel 16 nautical miles (30 km) south west of Hartland Point (50°47′N 4°44′W) by SM UB-86 (Kaiserliche Marine) with the loss of three of her crew.
• Pentyrch (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 5 nautical miles (9.3 km) west north west of the Brighton Lightship (United Kingdom of Great Britain and Ireland) by SM UB-40 (Kaiserliche Marine) with the loss of a crew member.
• Runswick (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and damaged in the Atlantic Ocean 3 nautical miles (5.6 km) north of Trevose Head, Cornwall (50°33′N 5°03′W) by SM UB-109 (Kaiserliche Marine). She was beached but was declared a total loss. Her crew survived.

19 April

• Alice Taylor (United Kingdom of Great Britain and Ireland): The coaster foundered on this date. Her crew were rescued.
• Elka (Greece): World War I: Convoy GaG16: The cargo ship was torpedoed and sunk in the Mediterranean Sea 50 nautical miles (93 km) off Cape Gati, Spain by SM U-34 (Kaiserliche Marine). Her crew survived.
• Lord Charlemont (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 22 nautical miles (41 km) north of the Isla de Alborán, Morocco (36°15′N 3°04′W) by SM U-34 (Kaiserliche Marine) with the loss of eight crew.
• Salambo (French Navy): World War I: The naval trawler was torpedoed and sunk in the Ionian Sea (38°30′N 18°06′E) by SM U-38 (Kaiserliche Marine). Her crew survived.
• SM UB-78 (Kaiserliche Marine): World War I: The Type UB III submarine struck a mine and sank in the Strait of Dover (51°01′N 1°17′E) with the loss of all 35 crew.
• War Helmet (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 3 nautical miles (5.6 km) east by north of the Owers Lightship (United Kingdom of Great Britain and Ireland) by SM UC-75 (Kaiserliche Marine). Her crew survived.

20 April

• Florrieston (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 6 nautical miles (11 km) east of South Stack, Anglesey by SM U-91 (Kaiserliche Marine) with the loss of nineteen of her crew.
• Lowther Range (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 20 nautical miles (37 km) west by north of South Stack (53°18′N 5°10′W) by SM U-91 (Kaiserliche Marine). Her crew survived.
• HMT Numitor (Royal Navy): World War I: The naval trawler struck a mine and sank in the North Sea off Orfordness, Suffolk (52°07′N 1°45′E) with the loss of five of her crew.

21 April

• Bellview (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 16 nautical miles (30 km) east north east of Cape Bon, Tunisia (37°13′N 11°21′E) by SM U-32 (Kaiserliche Marine). Her crew survived.
• Delta A (Belgium): World War I: The trawler was stopped and sunk in the Atlantic Ocean 18 nautical miles (33 km) south of St. Kilda, Inverness-shire, United Kingdom by SM U-19 (Kaiserliche Marine).
• Landonia (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 27 nautical miles (50 km) north west by west of Strumble Head, Pembrokeshire by SM U-91 (Kaiserliche Marine) with the loss of 21 of her crew. One of the survivors was taken as a prisoner of war.
• Normandiet (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 34 nautical miles (63 km) south west by west of the Calf of Man, Isle of Man by SM U-91 (Kaiserliche Marine) with the loss of nineteen of her crew.
• SM UB-71 (Kaiserliche Marine): World War I: The Type UB III submarine was depth charged and sunk in the Strait of Gibraltar (35°38′N 5°18′W) by HMML 413 (Royal Navy) with the loss of all 32 crew.
• Westergate (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 22 nautical miles (41 km) east of Start Point, Devon by SM UB-80 (Kaiserliche Marine) with the loss of 24 of her crew.

22 April

• Baron Herries (Royal Navy): World War I: The naval tug was torpedoed and sunk in the Atlantic Ocean 43 nautical miles (80 km) north by west of the Bishop Rock, Isles of Scilly (50°27′N 7°06′W) by SM U-91 (Kaiserliche Marine) with the loss of three of her crew. One of the survivors was taken as a prisoner of war.
• Dronning Maud (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 65 nautical miles (120 km) north north east of Cape Sigli, Algeria (38°00′N 4°56′E) by SM U-34 (Kaiserliche Marine) with the loss of a crew member.
• Eric Calvert (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 4 nautical miles (7.4 km) south south west of St Anthony Head, Cornwall 50°04′30″N 5°01′45″W) by SM UB-103 (Kaiserliche Marine) with the loss of two of her crew.
• USS Fenimore (United States Navy): The cargo ship was destroyed by fire in New York Harbor.
• Fern (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 5 nautical miles (9.3 km) east of the Kish Lightship (United Kingdom of Great Britain and Ireland) by SM U-104 (Kaiserliche Marine) with the loss of thirteen crew.
• Kheda Moulekar (France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32°08′N 32°50′E) by SM UB-53 (Kaiserliche Marine).
• Marshalla (United Kingdom of Great Britain and Ireland): World War I: The sailing vessel was shelled sunk in the Mediterranean Sea 50 nautical miles (93 km) north of Port Said, Egypt (32°11′N 32°39′E) by SM UB-53 (Kaiserliche Marine).
• HMT Pursuit (Royal Navy): The naval trawler was lost on this date.
• Sadika (France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32°13′N 32°40′E) by SM UB-53 (Kaiserliche Marine).
• SM UB-55 (Kaiserliche Marine): World War I: The Type UB III submarine struck a mine and sank in the Strait of Dover (51°01′N 1°20′E) with the loss of 23 of her 29 crew.
• Welbeck Hall (United Kingdom of Great Britain and Ireland): World War I: The ship was torpedoed and sunk in the Mediterranean Sea 75 nautical miles (139 km) north east by north of Port Said by SM UB-53 (Kaiserliche Marine) with the loss of four of her crew.

23 April

• HMS Brilliant (Royal Navy): World War I: First Ostend Raid: The Apollo-class cruiser was scuttled as a blockship at Ostend, West Flanders, Belgium.
• HMS C3 (Royal Navy): World War I: Zeebrugge Raid: The C-class submarine was scuttled at Zeebrugge, West Flanders.
• Frances (United Kingdom of Great Britain and Ireland): World War I: The ketch was scuttled in the Atlantic Ocean (46°33′N 12°05′W) by SM U-155 (Kaiserliche Marine) with the loss of two of her crew.

HMS Iphigenia

• HMS Intrepid (Royal Navy): World War I: Zeebrugge Raid: The destroyer was scuttled at Zeebrugge in an attempt to block the entrance to the Bruges Canal.
• HMS Iphigenia (Royal Navy): World War I: Zeebrugge Raid: The destroyer was scuttled at Zeebrugge in an attempt to block the entrance to the Bruges Canal.
• Laurium (United Kingdom of Great Britain and Ireland): World War I: The coaster struck a mine and sank in the North Sea off the Inner Dowsing Lightship (United Kingdom of Great Britain and Ireland) with the loss of a crew member.
• HMML 110 (Royal Navy): The motor launch was lost on this date.
• HMML 424 (Royal Navy): The motor launch was lost on this date.
• HMS North Star (Royal Navy): World War I: Zeebrugge Raid: The Admiralty M-class destroyer was shelled and sunk at Zeebrugge by Germ shore-based artillery.
• Peregrine (United Kingdom of Great Britain and Ireland): World War I: The trawler was shelled and sunk in Yell Sound by SM U-19 (Kaiserliche Marine). Her crew survived.
• HMT Plethos (Royal Navy): World War I: The naval trawler struck a mine and sank in the North Sea 40 nautical miles (74 km) 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 SM UB-105 (Kaiserliche Marine).
• HMS Sirius (Royal Navy): World War I: First Ostend Raid: The Apollo-class cruiser was scuttled as a blockship at Ostend.
• HMS Thetis (Royal Navy): World War I: Zeebrugge Raid: The Apollo-class cruiser was scuttled at Zeebrugge in an attempt to block the entrance to the Bruges Canal.
• Tyne Wave (United Kingdom of Great Britain and Ireland): World War I: The trawler was shelled and sunk in the North Sea 16 nautical miles (30 km) north east of Ronas Voe, Shetland Islands by SM U-19 (Kaiserliche Marine). Her crew survived.

24 April

• Agnete (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 4 nautical miles (7.4 km) 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 SM UB-105 (Kaiserliche Marine).
• Mabrouska (France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32°44′N 32°40′E) by SM UB-53 (Kaiserliche Marine).

25 April

• HMS Cowslip (Royal Navy): World War I: The Anchusa-class sloop was sunk in the Atlantic Ocean off Cape Spartel, Morocco by SM UB-105 (Kaiserliche Marine) 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 SM UB-31 (Kaiserliche Marine).
• Sevilla (Norway): World War I: The cargo ship was sunk in the English Channel 3 nautical miles (5.6 km) north west of Berry Head, Devon, United Kingdom (50°24′N 3°23′W) by SM UB-80 (Kaiserliche Marine) with the loss of a crew member.
• Sote (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 SM UC-64 (Kaiserliche Marine) with the loss of a crew member.
• HMS St. Seiriol (Royal Navy): World War I: The auxiliary minesweeper struck a mine and sank in the North Sea off the Shipwash Lightship (United Kingdom of Great Britain and Ireland) with the loss of twelve of her crew.
• SM U-104 (Kaiserliche Marine): World War I: The Type U 57 submarine was depth charged and sunk in St. George's Channel (51°59′N 6°26′W) by USS Cushing (United States Navy) and HMS Jessamine (Royal Navy) with the loss of 41 of her 42 crew.
• HMS Willow Branch (Royal Navy): World War I: The Q-ship was sunk in the Atlantic Ocean off Cabo Blanco, Mauritania (21°00′N 17°56′W) by SM U-153 and SM U-154 (both Kaiserliche Marine) with the loss of 58 of her crew.
• HM Torpedo Boat 90 (Royal Navy): The torpedo boat capsized and sank off Gibraltar.

26 April

• Angelina di Paola (Kingdom of Italy): World War I: The brig was sunk in the Mediterranean Sea north of Cape San Vito, Sicily by SM UB-68 (Kaiserliche Marine).
• Ethel (United Kingdom of Great Britain and Ireland): World War I: The schooner was shelled and sunk in the Irish Sea 19 nautical miles (35 km) north by east of the Smalls Lighthouse by SM U-91 (Kaiserliche Marine). Her crew survived.
• Leopold d'Or (France): World War I: The cargo ship was torpedoed and sunk in the Tyrrhenian Sea off San Pietro Island, Italy (39°55′N 7°02′E) by SM UB-48 (Kaiserliche Marine).
• Llyngwair (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the North Sea 5 nautical miles (9.3 km) south south east of Seaham Harbour, County Durham by SM UC-64 (Kaiserliche Marine) 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°07′N 32°32′E) by SM UB-53 (Kaiserliche Marine).
• Gresham (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 18 nautical miles (33 km) north west by north of Strumble Head, Pembrokeshire (52°14′N 5°05′W) by SM U-91 (Kaiserliche Marine). Her crew survived.
• Nemaat Kheda (France): World War I: The sailing vessel was sunk in the Mediterranean Sea (32°07′N 32°32′E) by SM UB-53 (Kaiserliche Marine). Her crew survived.
• Romany (United Kingdom of Great Britain and Ireland): World War I: The tanker was torpedoed and sunk in the Mediterranean Sea 47 nautical miles (87 km) west south west of Cape Spartivento, Italy by SM UB-48 (Kaiserliche Marine). Her crew survived.
• Walpas ( Russia): World War I: The sailing vessel was sunk in the Irish Sea 15 nautical miles (28 km) west by nort of Bardsey Island, Pembrokeshire by SM U-91 (Kaiserliche Marine).

28 April

• HM CMB-39B (Royal Navy): The Coastal Motor Boat was lost on this date.
• HMS Dalkeith (Royal Navy): World War I: The tug was torpedoed and sunk in Carloforte Bay, Sardinia, Italy by SM UB-48 (Kaiserliche Marine) with the loss of nine of her crew.
• Damao (Portugal): World War I: The cargo ship was sunk in St. George's Channel 12 nautical miles (22 km) west of Bardsey Island, Pembrokeshire, United Kingdom by SM U-91 (Kaiserliche Marine).
• Elba (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 6 nautical miles (11 km) north west of the Pendeen Lighthouse (50°13′N 5°48′W) by SM UB-103 (Kaiserliche Marine) with the loss of ten of her crew.
• HMT Emley (Royal Navy): World War I: The naval trawler was sunk in the Firth of Forth south of the Isle of May, Fife by SM UC-40 (Kaiserliche Marine) with the loss of eight of her crew.
• Kingstonian (United Kingdom of Great Britain and Ireland): World War I: the cargo ship was torpedoed and sunk in Carloforte Bay by SM UB-48 (Kaiserliche Marine) with the loss of a crew member.
• Moose (United Kingdom of Great Britain and Ireland): World War I: The tug was torpedoed and sunk in Carloforte Bay by SM UB-48 (Kaiserliche Marine).
• Oronsa (United Kingdom of Great Britain and Ireland): World War I: The passenger ship was torpedoed and sunk in St. George's Channel 12 nautical miles (22 km) west of Bardsey Island by SM U-91 (Kaiserliche Marine) with the loss of three of her crew.
• Poitiers (France): World War I: The cargo ship was sunk in the Atlantic Ocean 4 nautical miles (7.4 km) south west of Hartland Point, Devon, United Kingdom by SM U-60 (Kaiserliche Marine).
• Rimfakse (Norway): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 10 nautical miles (19 km) south west of Hartland Point (50°54′N 4°35′W) by SM U-60 (Kaiserliche Marine). Her crew survived.
• Upcerne (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 4 nautical miles (7.4 km) south east by east of Coquet Island, Northumberland by SM UC-40 (Kaiserliche Marine) with the loss of sixteen of her crew.
• Verdun (France): World War I: The cargo ship was sunk in the Gulf of Gabès 37 nautical miles (69 km) east of Kerkennah, Tunisia (34°49′N 11°52′E) by SM UC-20 (Kaiserliche Marine).

29 April

• Australier (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 6 nautical miles (11 km) south west by south of Dungeness, Kent (50°52′N 0°58′E) by SM UB-57 (Kaiserliche Marine) with the loss of five of her crew.
• Broderick (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 7 nautical miles (13 km) south south east of Hastings, East Sussex by SM UB-57 (Kaiserliche Marine). Her crew survived.
• Christiana Davis (United Kingdom of Great Britain and Ireland): World War I: The schooner was shelled and sunk in the Atlantic Ocean 8 nautical miles (15 km) south east by south of the Tuskar Rock, Ireland by SM U-105 (Kaiserliche Marine). 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°58′N 4°21′E) by SM UB-105 (Kaiserliche Marine). Her crew survived.
• HMS Dalkeith (Royal Navy): World War I: The naval tug was sunk in the Mediterranean Sea off San Pietro Island, Italy by SM UB-48 (Kaiserliche Marine) with the loss of nine of her crew.
• Ellis Sayer (United Kingdom of Great Britain and Ireland): The collier was lost on this date.
• Frogner (Norway): World War I: The cargo ship was sunk in the English Channel 3 nautical miles (5.6 km) off Portland Bill, Dorset, United Kingdom by SM UC-17 (Kaiserliche Marine). Her crew survived.
• Johnny Toole (United Kingdom of Great Britain and Ireland): World War I: The ketch was shelled and sunk in the Atlantic Ocean 3 nautical miles (5.6 km) south of the Tuskar Rock by SM U-105 (Kaiserliche Marine). Her crew survived.
• Kut Sang (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 40 nautical miles (74 km) east south east of Cape Palos, Spain by SM UB-105 (Kaiserliche Marine) with the loss of 59 of her crew.
• La Somme (France): World War I: The cargo ship was sunk in the English Channel 5 nautical miles (9.3 km) west south west of Dungeness (50°52′N 0°51′E) by SM UB-57 (Kaiserliche Marine) with the loss of a crew member.
• Maria (Greece): World War I: The vessel was sunk in the Mediterranean Sea (35°38′N 13°20′E) by SM U-27 (Austro-Hungarian Navy). Her crew survived.
• Prarial (French Navy): The Pluviose-class submarine was run down and sunk in the English Channel off Le Havre, Seine Maritime by Tropic (United Kingdom of Great Britain and Ireland) with the loss of nineteen of her 26 crew.
• Saint Chamond (France): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 14 nautical miles (26 km) north of St. Ives Head, Cornwall, United Kingdom (50°15′N 5°30′W) by SM U-60 (Kaiserliche Marine). Her crew survived.

30 April

• Conway (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 38 nautical miles (70 km) south of Cape Palos, Murcia, Spain (37°10′N 0°28′W) by SM UB-105 (Kaiserliche Marine). Her crew survived.
• Ella Sayer (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 15 nautical miles (28 km) east by north of the Royal Sovereign Lightship (50°49′N 0°48′E) by SM UB-57 (Kaiserliche Marine) with the loss of two of her crew.
• Isleworth (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 3 nautical miles (5.6 km) south west of Ventnor, Isle of Wight by SM UC-17 (Kaiserliche Marine) with the loss of 29 of her crew.
• Kafue (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 11 nautical miles (20 km) south west of the Mull of Galloway, Wigtownshire by SM U-86 (Kaiserliche Marine) with the loss of a crew member.
• Kalliope (United Kingdom of Great Britain and Ireland): World War I: The sailing vessel was sunk in the Mediterranean Sea 45 nautical miles (83 km) off Alexandria, Egypt by SM UC-74 (Kaiserliche Marine).
• Kempock (United Kingdom of Great Britain and Ireland): World War I: The coaster was shelled and sunk in the Irish Sea 6.5 nautical miles (12.0 km) south east by south of the Copeland Islands by SM U-86 (Kaiserliche Marine). Her crew survived.
• SM UB-85 (Kaiserliche Marine): 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 (Royal Navy).
• Umba (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 1 nautical mile (1.9 km) south of the Royal Sovereign Lightship (United Kingdom of Great Britain and Ireland) by SM UB-57 (Kaiserliche Marine) with the loss of twenty of her crew.

Unknown date

• Cicero (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was scuttled in the Baltic Sea to avoid capture by the Germans.
• Emilie (United Kingdom of Great Britain and Ireland): 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 SM U-154 (Kaiserliche Marine) with the loss of all 28 crew.
• Obsidian (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was scuttled in the Baltic Sea to avoid capture by the Germans.
• Prarial (French Navy): The submarine collided with a merchant vessel and sank with some loss of life.
• SM UC-79 (Kaiserliche Marine): 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.