The sea resembles a border with gaps in every direction because hostile forces can approach through almost any route. Unlike a land frontier, the ocean offers few fixed barriers that funnel movement through a small number of defended positions. A navy therefore needs enough self-sufficient cruisers to patrol trade routes, report contact, and hold out until stronger forces respond. Trade defense and interdiction consume cruiser strength even when no single patrol produces a decisive fleet action.
Notable Point · 29:36-31:00
Why sea control consumes cruisers
Cruisers are needed in quantity because naval theatres have too many routes and local threats for a fleet to cover from a few concentrated positions.