US and Japanese warships contest control of Savo Sound off Guadalcanal. At 3.59 AM, Japanese destroyer Kawakaze torpedoes destroyer USS Blue, wrecking her engines and steering gear (9 killed, 21 wounded). Despite attempts to tow her, USS Blue will be scuttled at 10.21 PM next day. US aircraft counterattack Kawakaze without success (1 man wounded by machinegun fire). USAAF 67th Fighter Squadron with Bell P-400 Airacobra fighters arrives at Henderson Field.
US 5th Air Force bombers attack Japanese bases at Lae, New Guinea, and Rabaul, New Britain.
At 9.50 AM 12 miles off the coast of Brazil, U-507 sinks Swedish MV Hammaren with the deck gun and 5 torpedoes (6 dead, 25 survivors in 1 lifeboat reach Brazil). Brazil declares war on Germany due to these attacks in Brazilian waters by U-507 that have killed over 600 people from neutral countries in a week.
Case Blue. At midday, pontoon bridges begin carrying German 16th Panzer Division across the River Don. The way to the Volga and Stalingrad lies open. In the Black Sea, Soviet submarine M3 disappears near Odessa, Ukraine, presumably sunk on a German mine.
At 1.10 PM 25 miles North of Taipei, Formosa (Taiwan), US submarine USS Haddock sinks Japanese transport ship Tatsuho Maru carrying 10,000 gallons of aviation fuel to Dutch East Indies (12 crew and 26 passengers killed).
Mediterranean. 5 miles West of Tobruk, Italian torpedo boat Generale Antonio Cantore sinks on a mine (laid on August 12 by British submarine HMS Porpoise).
Japanese submarine I-30 departs Lorient, France, to return to Japan after her refit by the Germans. I-30 carries 50 top secret "T-Enigma" coding machines for communication between Kriegsmarine and Japanese Navy, plus other German technical developments (blueprints of the Würzburg air defense ground radar, 5 G7a aerial torpedoes and 3 G7e electric torpedoes, torpedo data computers, 200 20-mm anti-aircraft guns and Zeiss fire control systems) and industrial diamonds.
Caribbean. In the afternoon, 185 miles North of the Panama Canal, a Douglas B-18 Bolo bomber (US 45th Bombardment Squadron, from Howard Field in the Canal Zone) spots U-654 running at periscope depth and sinks her with depth charges (all 44 hands lost).
Overnight in dense fog 225 mile South of Halifax, Nova Scotia, New Zealand troop transport HMNZS Awatea rams US destroyer USS Buck (escorting convoy AT-20), wrecking her keel and stern (7 killed). Primed depth charges are dislodged from USS Buck and explode under HMNZS Awatea causing damage. US destroyer USS Ingraham arrives to assist but collides with US Navy oiler USS Chemung. Again, primed depth charges on USS Ingraham explode and rip the ship apart (218 killed, 11 survivors rescued by USS Chemung). USS Chemung tows USS Buck to Boston and HMNZS Awatea is escorted to Halifax for repairs.