Battle of Sluys
The Battle of Sluys was a naval battle between French and English forces in the first years of the Hundred Years War. On June 24, 1340, a French flotilla engaged English ships attempting a landing in France. The English used superior mobility to defeat their opponents and capture almost the entire French fleet. The victory secured the English Channel and insured that the war would be fought primarily on French soil.
A History of War at Sea, by Helmut Pemsel, Naval Institute Press, 1975