April 12
1782 naval Battle of the Saints ends
1861 Bombardment of Ft. Sumter begins, US Civil War begins
1862 Andrew's Raid: "The Great Locomotive Chase"
1863 Battle of Teche River begins
1864 Battle of Ft. Pillow
1865 Union troops occupy Mobile and Montgomery
1917 Battle of Vimy Ridge ends
1918 Battle of Hazebrouck begins
1936 1st flight Bristol Blenheim
1940 Norwegian Torpedo Boat Storm wrecked south of Bergen. Norwegian Patrol ship Micheal Sars and KM Patrol Boat Senja bombed/sunk by British aircraft at Narvik. Guard ship Sperm scuttled. French Sub Chaser Chasseur 107 sunk in a collision with SS Shelspra
1941 Yugoslav Monitor Drava bombed/sunk and Vardor, Sava, and Morava scuttled off Cip, Yugoslavia. Trawler HMS Rypa sank in a storm in Loch Ewe.
1942 PT-35 scuttled at Cebu City.
1944 PT-135 ran aground/scuttled off New Britain. Sub I-174 sunk by USN PB4Y east of Truk.
1945 USN LCS-33 and destroyer USS Mannert L. Abele sunk by Kamakazes off Okinawa. LCT-66 lost at Pearl Harbor. US LST-493 ran aground and sank off Plymouth, England. Sub RO-64 sunk by mine in Hiroshima Bay during training. U-486 sunk by sub HMS Tapir off Norway. U-1024 captured by Frigates HMS Loch Glendhu and Loch More, sinks next day.
1970 Soviet sub K-8 sinks in the Bay of Biscay after a fire 4 days earlier

13 April
1204 Siege of Constantinople ends
1777 Battle of Bound Creek
1861 Bombardment of ft. Sumter ends
1868 British capture Magdala
1918 Battle of Bailleul begins
1940 Norwegian Minelayer Froya scuttled, then torpedoed by U-boat near Trondheim. KM Minesweeper M-1108 sunk in a collision off Denmark. U-64 bombed/sunk off Bjerkvik, Norway.
2nd Battle of Narvik: KM Destroyers Diether Von Roeder, Eric Giess, Herman Kunne sunk, Bernd Von Arnim, Erich Koellner, Georg Thiele, Hans Ludeman, Wolgang Zenker scuttled, Norwegian Patrol Boat Kelt bombed/sunk.
1941 Armed Merchant Cruiser HMS Rajputana sunk by U-108 in the Denmark Strait.
1942 Trawler HMS Coral bombed/sunk at Malta. Trawler HMS Lord Snowdon sunk in a collision off Falmouth
1943 Norwegian Destroyer Eksdale sunk by E Boats S-90 and 112 off Lizard Head.
1944 Destroyer Ikazuki sunk by sub USS Harder south south east of Guam.
1945 Soviets capture Vienna. Chile declares War on Japan. KM Torpedo Boat T-16 bombed/sunk at Fredrikshavn, Denmark. TA-45 sunk by R.N. MTBs in the Adriatic Sea.
1972 Battle of An Loc begins

14 April
43 B.C. Battle of Forum Gallorum
69 1st Battle of Bedriacum
1205 Battle of Adrianople
1471 Battle of Barnet
1639 Battle of Chemnitz
1863 Battle of Teche River ends, Gunboats CSS Diana and CSS Queen of the West sunk
1940 KM Gunnery Training ship Brummer damaged by sub HMS Sterlet in the Kattegat, sinks next day. Minesweeper M-1101 damaged by mine and beached in Oslofjord. Sub Tender Oldenburg sunk by HMS Sunfish in the Skagerrak. Norwegian Torpedo Boat Teist scuttled in the Skagerrak.
1941 Free French Gunboat Conquerante bombed/sunk ay Falmouth
1942 U-85 sunk by Destroyer USS Roper off Cape Hatteras. U-252 sunk by Sloop HMS Stork and Corvette Vetch south west of Ireland
1943 Trawler HMS Adonis sunk by E Boats off Lowestoft. U-526 sunk by mine in the Bay of Biscay
1944 Bombay Explosion (https://en.wikipedia.org/wiki/Bombay_Explosion_(1944)), sinks Landing Ship HMIS El Hind amoungst others. U-448 sunk by Frigate HMCS Swansea and Sloop HMS Pelican
1945 Frigates CD-31 and Nomi sunk by sub USS Tirante in Hiyo Bay. U-235 sunk by KM Torpedo Boat T-17 in the Kattegat. U-1206 scuttled after developing leaks, possibly from hitting a wreck.
1969 N. Korea shoots down USN EC-121
1988 Frigate USS Samuel B. Roberts damaged by a mine in the Persian Gulf
1994 2 US Army UH-60s shot down by USAF F-15s over Iraq

15 April
1068 Siege of Bari ends
1395 Battle of Terek River
1450 Battle of Formigny
1632 Battle of Rain
1642 Battle of Kilrush
1864 Ironclad USS Eastport strikes a torpedo on the Red River south of Grand Ecore, La., and is beached.
1858 Battle of Azimghur
1900 Siege of Catubig begins
1917 Battle of Hazebrouck, and Battle of Bailleul, end
1940 Norwegian subs A-3 and 4 scuttled at Tonsburg. KM Minesweepers Carsten Janssen and H.M. Behrens sunk by HMS Snapper in the Kattegat. U-495 sunk by Destroyers HMS Fearless and Brazen near Harstad. Patrol Ship Vp-811 sank in the North Sea.
1942 PT-41 destroyed on Mindanao by the US Army.
1943 Italian sub Archimede sunk by USN PBY off Brazil. US Patrol Boat YP-453 ran aground and sank on the Bahama Bank.
1944 Minesweeper W-7 sunk by sub HMS Storm in the Indian Ocean off the Nicobar Islands
1945 Frigate HMS Ekins damaged beyond repair by a mine in the North Sea. KM Minesweeper M-368 sunk in a collision with a U-boat off Norway. Patrol Boat Vs-58 sunk by mine north east of Kiel. U-103 bombed/sunk at Kiel. U-285 sunk by Frigates HMS Grindall and Keats south west of Ireland. U-1063 sunk by Frigate HMS Loch Killin west of Lands End. U-1235 sunk by Destroyer Escorts USS Stanton and Frist.
1952 1st flight B-52
1986 US bombs Libya

17 April
1555 Siege of Siena ends, as does the Republic of Siena
1799 Battle of San Juan begins
1863 Grierson's Raid begins
1864 Battle of Plymouth begins
1865 Union troops capture Columbus, Ga. Gunboat CSS Chattahoochee scuttled, Unfinished Ironclad CSS Jackson destroyed
1934 1st flight Fairey Swordfish
1941 Yugoslavia surrenders, Destroyer Zagreb scuttled at Boka Kotorska.
1943 U-175 sunk by USCG Cutter Spencer south west of Ireland
1944 U-342 sunk by RCAF PBY south west of Iceland. U-986 sunk by Minesweeper USS Swift and US Patrol Craft PC-619 south west of Iceland.
1945 R.N. MTB 697 sunk by mine in the Adriatic.
1961 Bay of Pigs Invasion begins
1975 Khmer Rouge captures Phnom Penh, Cambodian Civil War ends.

19 April
1775 Paul Revere's Ride
1797 Battle of Neuwied
1847 battle of Cerro Gordo
1864 battle of Dybbol
1940 Norwegian Torpedo Boats Grib, Jo, and Ravn scuttled at Lyngar. Torpedo Boat Sael sunk by E Boats in Hardangerfjord. Sub HMS Sterlet probably sunk by KM Minesweeper M-75 and Torpedo Boat T-190 south of Norway
1941 Trawler HMS Young Ernie sunk in a collision in the Tyne. KM Flackship V-709 sunk in Bay of Biscay.
1942 Doolittle Raid:"30 seconds over Tokyo": 4 picket ships sunk, Aircraft Carrier Ryujo damaged during construction.
1943 Sub HMS P 615 sunk by U-123. Sub HMS regent sunk by mine in the Strait of Otranto
1944 Soviet sub L-6 sun k by KM Sub Chaser UJ-104 off Constanta. Sub USS Gudgeon bombed/sunk off Iwo Jima
1983 US Beirut Embassy bombing
1988 US air attacks on Iran: Missle boat Joshan and Frigate Sahand sunk.

20 April
1657 naval Battle of Santa Cruz de Tenerife
1770 Battle of Aspindza
1775 Siege of Boston begins
1809 Battle of Abensberg
1864 Battle of Plymouth ends
1938 1st flight Ki-36
1940 Trawler HMS Rutlandshire damaged by bombed, beached and broke up in Namsenfjord. Norwegian Torpedo Boat Stegg sunk by KM Gunnery Training ship Bremse, and Patrol Boat Smart sunk by Schiff 18, Minesweeper Tyr captured near Bergen.
1941 Trawler HMS Topaze rammed/sunk by Battleship HMS Rodney off the Clyde. R.N. Motor Launches ML 1003 and 1037 lost as cargo when SS Empire Durance is sunk by U-73 south west of Rockall. Greek Destroyer Psara bombed/sunk in Saronic Gulf.
1942 Destroyer HMS Cotswold damaged by mine and beached, refloated, repaired, returned to service.
1944 Destroyer USS Landsdale torpedoed/sunk by JU-88s off Algiers
1961 Bay of Pigs Invasion ends
1978 Soviets shoot down KAL Flight 902

April 23
1014 Battle of Clontarf
1521 Battle of Villalar
1655 Siege of Santo Domingo begins
1918 Destroyer USS Stewart sinks U Boat off France. Zeebrugge Raid.
1940 KM Sub Chaser UJ-B sunk by HMS Tetrarch in the Skagerrak.
1941 Greek Battleships Kilkis and Lemnos bombed/sunk at Salamis
1943 U-189 sunk by RAF B-24 east of Cape Farewell, Greenland. U-191 sunk by destroyer HMS Hesperus south east of Cape Farewell. US Patrol Boat YP-395 ran aground and sank off New Caledonia. IJN Patrol Boat PB-39 sunk by USS Seawolf east of Formosa
1944 Destroyer Amigiri sunk by mine in Makassar Strait.
1945 US Patrol Ship PE-56 sunk by U-853 off Cape Elizabeth, Maine. U-183 sunk by sub USS Besugo in the Java sea.
1949 Red China's People's Liberation Army-Navy (Navy) Est.

April 26
1805 US Marines capture Derna, Tripoli "The halls of Tripoli"
1864 Red River Campaign: The Fed. fleet & Union Army continues its retreat. Ironclad USS Eastport, beached on April 15th after striking a torpedo, is burned to prevent capture. CS field artillery attacks stragglers damaging Gunboat USS Cricket, killing 12 and wounding 19 of her 50 complement. A shell explodes pump boat Champion No. 3's boiler, destroying her and killing 189 of 204 onboard.
1865 Gen. Joe Johnston surrenders the Army of Tennessee in N.C.
1915 Italy declares War on Austria-Hungary
1937 Guernica Air Raid
1940 Norwegian Destroyer Garm bombed/sunk at Bjordal. KM Schiff 37 sunk west of Alesund by Cruiser HMS Birmingham
1941 Greek Torpedo Boat Kydonia bombed/sunk at Morea
1942 Destroyer USS Sturdevant sunk by mine north of Key West. IJN sub RO-30 sunk by sub USS Tautog near Johnson Island
1943 USN Patrol Boat YP-47 sunk in a collision with USN Minesweeper YMS-110 off Statin Island, NY
1944 U-488 sunk by 3 USN Destroyer Escorts west of the Cape Verde Islands. KM Torpedo Boat T-29 sunk off Jentilez, France. IJN sub I-180 sunk by Destroyer Escort USS Gilmore south-west of Cherikof Island, Alaska
1945 Battle of Bautzen ends
1952 Destroyer-Minesweeper USS Hobson sunk in a collision with USS Wasp

April 27
1296 Battle of Dunbar
1521 Battle of Mactan
1522 Battle of Bicocca
1650 Battle of Carbisdale
1777 Battle of Ridgefield, Conn.
1813 US troops capture York, Canada
1862 Battle of New Orleans: 4 small forts on the north side of New Orleans surrender or are evacuated
1865 Mississippi River steamer Sultana's boiler explodes killing 1,200 to 1,700 of over 2,000 men on board, mostly Union Army ex-POWs heading north for home.
1916 Battleship HMS Russel sunk by mines off Malta
1941 Germans capture Athens. CAT ship HMS Patia bombed/sunk off Coquet Island. Destroyers HMS Diamond and Wryneck bombed/sunk by JU-87s off Crete.
1943 U-174 sunk by USN PV-1 Ventura south of Newfoundland
1944 U-803 sunk by mine off Swinemunde, raised and used for parts. Cruiser Yubari sunk by USS Bluegill south west of Truk
1945 Frigate HMS Redmill irreparably damaged by U-1105 west of Ireland, scrapped post War. KM Sperrbrecher 167 sunk by mine off Cuxhaven.
1996 Lebanon War ends