Foresight's protection of the monitors turns sea control into a practical question about what maritime freedom makes possible. Local control off the Belgian coast allowed supporting ships to approach the shore and apply naval gunfire to the land battle. Elsewhere, the same freedom might carry goods and convoys, keep an economy supplied, or deny those options to an opponent. Holding water without using that advantage accomplishes little. The lesson is to judge sea control by the military and economic action it enables.
Notable Point · 30:41-31:32
Sea control matters when it enables action
The Yser example becomes a wider lesson: sea control enables bombardment, transport, trade, and denial.