At 5.40 AM 35 miles South of Cape Fear, North Carolina, U-558 sinks British anti-submarine trawler HMS Bedfordshire, which is on loan to the US Navy (all 37 hands lost).
Mediterranean. British destroyer HMS Jackal, damaged by bombers yesterday burns out of control while under tow by destroyer HMS Jervis. HMS Jervis torpedoes the wreck of HMS Jackal off Sidi Barrani, Egypt, and returns to Alexandria with 650 survivors from HMS Kipling, Jackal and Lively.
Soviet Southern and Southwestern Fronts begin the Kharkov offensive, attacking towards Kharkov out of the Izium salient. After 1 hour artillery barrage from 6.30 – 7.30 AM and 20 minutes of aerial bombardment, Soviet forces move forward at 7.30 AM supported by T34 and British lend lease Mark II Valentine tanks, making gains of 3-10 km. However, German 6th Army, under General Paulus, is preparing to launch its own offensive to cut off Soviet troops in the Izium salient. Soviets meet stiff German resistance, including 2 Sturer Emil self-propelled tank destroyers named Max and Moritz, and realize they are facing many more German troops than expected. Soviet 38th Army withdraws 3 tank Brigades to protect against a counterattack by German 3rd and 23rd Panzer Divisions in the Kharkov area. In the Crimea, Soviet troops withdraw from the Kerch Peninsula in the face of frontal attacks from German 11th Army. With this battle won, many aircraft from Wolfram von Richthofen’s Fliegerkorps VIII are immediately deployed to Kharkov to resist the Soviet offensive.
Soviet submarine K-23 attacks a German convoy off Nordkyn, Northern Norway. Convoy escorts UJ1101, UJ1108 and UJ1110 counterattack with depth charges and sink K-23 (all hands lost).
In the Gulf of St. Lawrence 50 miles Southwest of Anticosti Island, U-553 sinks Dutch SS Leto and British SS Nicoya. 2 miles off the entrance to Southwest Pass, Mississippi River, U-507 sinks US turbine tanker Virginia carrying 180,000 barrels of gasoline. In the Caribbean 90 miles North of Bonaire, U-69 sinks Norwegian tanker MV Lise with torpedoes and the deck gun (12 killed, 21 survivors including 5 on a raft who are not found until May 31).
In the middle of the Atlantic 800 miles West of Ireland, U-94 and U-124 attack convoy ONS-92. U-94 sinks Panamanian SS Cocle at 3.40 AM (5 killed, 37 survivors). U-124 sinks British catapult armed merchant Empire Dell and British SS Llanover at 2 AM (2 dead, 92 survivors) and Greek SS Mount Parnes and British SS Cristales at 4 AM (all 115 hands survive).
Following the failed invasion of Port Moresby, Papua, the Japanese plan to occupy Nauru and Ocean islands in the South Pacific. Troop transports Kinryū Maru and Takahata Maru depart Rabaul, escorted by cruiser Tatsuta, destroyers Uzuki and Yuzuki and minelayers Okinoshima and Tsugaru. At 4.52 AM 125 miles East of Rabaul, US submarine USS S-42 severely damages minelayer Okinoshima which is taken in tow by a destroyer. USS S-42 is counterattacked with depth charges by the escort ships for 6 hours causing major damage and forcing her to return to base at Brisbane, Australia. Japanese repair ship Shoei Maru is called out from Rabaul to assist Okinoshima. At 6.40 AM, Okinoshima capsizes and sinks in St. George's Channel. Repair ship Shoei Maru turns back to Rabaul but is hit by 2 torpedoes from US submarine USS S-44 at 9.57 AM and sinks at 2.40 PM.