In the Gulf of Mexico, U-506 torpedoes US tanker SS David McKelvy, carrying 81,000 barrels of crude oil which explodes (17 killed, 25 survivors many horribly burned, 2 men survive in fresh water tanks in the ship´s bottom until the fire burns out). SS David McKelvy will be beached on the Louisiana coast but declared a total loss. U-564 sinks neutral Mexican tanker SS Potrero del Llano by mistake off the Southeast tip of Florida (13 dead, 22 survivors picked up by American patrol vessel USS PC-536 and taken to Miami). This incident will contribute to Mexico’s declaration of war against Germany in June. US Commander in Chief United States Fleet and Chief of Naval Operations (COMINCH-CNO) Admiral Ernest King recognises the unacceptable losses on the US East coast (109 ships in 4 months) and begrudgingly allows Vice-Admiral Adolphus Andrews, in command of Eastern Sea Frontier, to organise an interlocking convoy system running from Newport, Rhode Island, to Key West, Florida, consisting in part of small cutters and private vessels.
In the Caribbean 50 miles West of Grenada, U-155 sinks Belgian MV Brabant. 14 miles Southwest by of Grand Cayman, U-125 sinks Honduran SS Comayagua. U-162 continues creating havoc off the coast of South America. 90 miles Northeast of Barbados, U-162 uses 6 torpedoes to sink British tanker SS British Colony, carrying 9800 tons of Admiralty fuel oil (4 lost, 43 survivors make land near Bridgetown, Barbados).
Mediterranean. 5 miles off Port Said, Egypt, at the mouth of the Suez Canal, Allied convoy runs into a minefield laid by U-561 on April 14. Greek SS Mount Olympus sinks and Greek SS Fred is damaged. Norwegian SS Hav is towed to shore and beached but burns out and is a total loss. At 9 PM off Ras el Hilal, Libya, British submarine HMS Turbulent uses the deck gun to shell tiny Italian sailing vessel San Giusto, which is carrying 161 tons of gasoline and explodes.
At 2 PM in the English Channel, near Cherbourg, RAF aircraft sink minesweepers M26 and M256. In the North Sea, minesweeping trawler M-1307 German hits a mine and sinks.
Kharkov offensive. Soviets continue advancing West out of the Izium salient, but Soviet 28th Army, forming the Northern pincer advancing from another salient near Volchansk, is pounded to a standstill by Luftwaffe Fliegerkorps VIII, newly-arrived from the Crimea. Soviet fighters sent in to engage the Germans are decisively beaten despite being numerically superior. Hitler orders General Ewald von Kleist to counterattack with his 1st Panzergruppe. In the Black Sea, Soviet destroyer Dzerzhinski sinks on a Soviet mine near Sevastopol.
“AF is short of water”. US cryptologists learn that Midway Atoll, at the Northern end of the Hawaiian island chain, is the target of a coming Japanese naval attack.
US submarine USS Tuna sinks Japanese transport Toyoharu Maru 65 miles off Sohuksando, Korea.