Action of 15 August 1917

Action of 15 August 1917
	Part of World War I
Date	15 August 1917
Location	off Humber estuary, North Sea52°57′00″N 2°25′00″E / 52.950000°N 2.416670°E
Result	Two British ships sunk
Belligerents
Royal Navy	Imperial German Navy
Commanders and leaders
Thomas Crisp †; William “Johnsey” Manning (MIA)	(possibly Kpt. Karsten von Heydebreck)
Strength
2 armed smacks	1 U-boat (possibly SM UC-63)
Casualties and losses
1 killed,; 7 missing; 2 ships sunk	unknown

The action of 15 August 1917 was a naval engagement which occurred during the First World War. The action was fought between a German U-boat (believed to be SM UC-63) and two naval trawlers, Nelson and Ethel & Millie, in the North Sea.