11 April 1942
Atlantic Ocean : German submarine U-123 torpedoed and fatally damaged US tanker Gulfamerica within 5 kilometers of Jacksonville, Florida, United States at 0422 hours, killing 19 of 48 aboard; the burning hulk would finally sink 5 days later. German submarine U-203 torpedoed and damaged US tanker Harry F. Sinclair Jr. 20 kilometers southeast of Swansboro, North Carolina, United States at 1320 hours, killing 10 of 36 aboard; the hulk would later be towed for repairs. 20 kilometers further east, U-160 torpedoed and sank British passanger ship Ulysses; all 290 aboard survived.
German submarine U-103 torpedoed and sank Norwegian cargo ship Grenanger in the middle of the Atlantic ocean at 1855 hours; all 36 aboard survived.
North Sea : German tanker Eurosee struck a mine and sank off Netherlands
Boulogne-sur-mer , France : Operation J : Two British Army commandos inflitrated Boulogne harbour with a canoe in the dark and sank a 4.000 ton German tanker laying in anchor with limpet mines then escaped back to sea where they were picked up by Royal Navy motor launch ML102 and returned to Dover.
Arctic Ocean : Luftwaffe Ju 88 aircraft attacked Allied convoy QP-10 returning from Russia to UK , damaging ship Stone Street and sinking British ship Empire Cowper (19 were killed) with bombs; a heavy snow storm prevented the Germans from launching another air attack on returning Arctic convoy.
Mediterranean Sea : Royal Navy submarine HMS Torbay attacked two Italian schooners on the surface with her deck gun northwest of Corfu, Greece, sinking Gesu Crocifisso with gunfire and forcing Natalina to ground to prevent sinking.
Egyptian transport ship Kawsar was bombed by Luftwaffe JU-88 aircraft , badly damaged and towed back to Port Said where she was declared a total loss.
Malta : Luftwaffe JU-87 dive bombers attacked La Valletta harbor, Malta, bombing and wrecking Royal Navy destroyer HMS Kingston in the dry dock where she was declared a total loss.
Crimea , Ukraine : A Soviet landing attempt near Eupatoria (Yevpatoria) near Sevastopol, Russia was halted by the Germans.
Pacific Ocean : American submarine USS Trout torpedoed and damaged Japanese tanker Nisshin Maru 5 miles off the southern coast of Japan.
American submarine USS Thresher provided a weather report on Tokyo, Japan for the incoming Doolittle Raiders.
Philippines : US Army Brigadier General Ralph Royce led 10 B-25 bombers and 3 B-17 bombers from Darwin, Australia to Mindanao, Philippine Islands; they were to be used for bombing Japanese forward positions. On the Bataan peninsula on the island of Luzon, 350 Filipino prisoners of war were killed by the Japanese north of Mount Samat during the Bataan Death March.
Burma : In Burma, British and Indian troops formed a new defensive line, Minhia-Taungdwingyi-Pyinmana, on the Irrawaddy River. After dark, the Japanese reached this line, launching a first attack on the Indian 48th Brigade at Kokkogwa.
Dutch East Indies : American submarine USS Searaven evacuated 33 Australian Army personnel from Timor Island.
New Guinea : US A-20 Havoc bombers attacked Japanese shipping in the Gulf of Huon off Lae, Australian New Guinea, bombing and fatally damaging transport Taijun Maru which sank next day.
Rabaul , New Britain : Eight B-26 Marauder bombers took off from Port Moresby, Australian Papua at 0900 hours; one of them would return to base due to engine trouble. The remaining seven attacked Vunakanau airfield and Lakunai airfield near Rabaul, New Britain, causing minimal damage. As the bomber crews returned to base, they reported a sighting of a fleet carrier (most likely mis-identified Kasuga Maru), causing the commanders to scramble to prepare a major strike against the target.