Blockade requires a navy to exercise command of the sea rather than simply declare its intentions. Submarines can attack shipping, but they are poorly suited to stopping, inspecting, and controlling merchant traffic. Surface ships carry the crews and trained personnel needed for boarding and search work. Older cruisers could perform distant blockade duty without requiring the most advanced warships in the fleet.
Notable Point · 10:45-12:12
Blockade depends on practical sea control
Blockade requires practical sea control, and surface ships usually carry the burden of stopping, searching, and policing merchant traffic.