Battle of the River Plate. Graf Spee spots British cruisers HMS Exeter, Ajax & Achilles. Intent on battle, Capt. Langsdorff closes rapidly ignoring safer options (pick off the smaller ships with his longer range guns or outrun the warships). At 6.18 AM he opens fire on the heavy cruiser Exeter from 11 miles. Commodore Harwood’s plan is to spread his ships & split Graf Spee’s fire. All three cruisers return fire by 6.23. Ajax & Achilles 6-inch shells rake Graf Spee’s topside but do not penetrate Graf Spee’s armor. Achilles is hit (4 dead) & Exeter is badly damaged by seven 11-inch shells (61 crew killed) but continues firing. At 6.38, 8-inch shell from Exeter penetrates Graf Spee’s armor, wrecking her fuel processing system. With only enough fuel for 16 hours, Graf Spee is forced to flee to the port of Montevideo, Uruguay, pusued by HMS Ajax & Achilles.
In the North Sea, Submarine HMS Salmon torpedoes German cruisers Leipzig & Nürnberg. Both stay afloat and will be repaired. Leipzig is so badly damage that she will never again be fit for combat duty and is only used as a training ship.