How did the Dunkirk evacuation use the Strait of Dover in 1940?

During the 1940 Dunkirk evacuation, also known as Operation Dynamo, the Strait of Dover served as the critical maritime corridor between the French coast and England.1

To facilitate the rescue of over 338,000 Allied troops, the British Admiralty established three specific evacuation routes—designated as routes X, Y, and Z—that crossed the strait to reach the port of Dover and other English destinations. Route Z was the shortest and southernmost of these paths.2

Throughout the nine-day operation, hundreds of naval vessels and civilian craft navigated these waters to transport soldiers from the beaches and harbor of Dunkirk across the strait. Despite the strategic importance of the passage, the evacuation was conducted under constant threat, as the area was subject to aerial attacks by the German Luftwaffe and shelling from the French coast.321