Sea control differs from territorial possession. A state cannot declare a stretch of water permanently its own, because control lasts only while ships can patrol it and prevent an opponent from using it. Maritime advantage therefore depends on sustained presence rather than a one-time conquest. Napoleon's expedition remained vulnerable even after moving successfully through the Mediterranean.
Notable Point · 23:23-23:51
Why sea control has to be continually enforced
Unlike territory, an expanse of sea cannot simply be claimed once and held forever; control depends on ships continuing to patrol and contest its use.