The Dover Castle before her wartime service. Image courtesy United Kingdom Government.
- German U-boat UC-67 torpedoes the British hospital ship HMHS Dover Castle in the Mediterranean Sea 80 km north of Bone. The initial explosion kills seven boiler stokers; the crew manages to evacuate the wounded onto HMS Cameleon. The captain and a small crew attempt to save the ship, but she is hit by a second torpedo an hour later and sinks.
- The French Minister of Marine states that Germany has sunk 2,400,000 tons of Allied shipping so far this year
- German troops on the Western Front make three successful attacks in Champagne
- Italian forces on the Southern Front take, but then lose Kostanjevica; they succeed in capturing ten guns
