The mine belt functions as a standing obstacle around the United Kingdom. An opponent cannot move freely into British waters simply because no battle fleet is visible at that point. The game abstracts the work of laying, sweeping, and maintaining the fields, but the map still shows how persistent sea-denial weapons shape safe routes and fleet movement. Later campaign reports show the cumulative damage caused by this defensive system.
Notable Point · 5:03-5:24
Minefields turn home waters into a barrier
The campaign map shows Britain ringed with mines that restrict enemy movement even where no surface squadron is visible.