The Channel stretches roughly 350 miles, reaches about 150 miles at its widest, and narrows to 21 miles at the Strait of Dover. Its 29,000 square miles and heavy maritime traffic made it a British weak spot. Responsibility was divided among the Dover, Portsmouth, Portland, Plymouth, and other command areas along its length. This shortened local observation and decision cycles when communications had limited range. The effectiveness of the arrangement still depended on neighboring commands cooperating against E-boats.
Chapter · 4:24-6:06
Channel geography creates a command problem
The English Channel's narrow, busy waters made it Britain's vulnerable maritime frontier, while several commands divided responsibility along its length.