Dover
Lock and Key of the Kingdom

Old-type destroyers prowl the waters off Dover to “Seek Out, Engage and Destroy” - motto of the Royal Navy.
Since the fall of France they and their sister ships have helped to escort a thousand convoys through the Strait.

In the Strait of Dover a launch takes aboard a downed airman saved by a rescue buoy.
Steel chambers like the one at right are anchored at intervals in the English Channel. In their cabins parachuting fliers find provisions, medical supplies, and radio sending sets. The ramp is for exhausted swimmers. A depth charge for U-boats is carried by the rescue launch.