The United States in the Civil War stationed her fleets off the Southern ports, not because she feared for her own, but to break down the Confederacy by isolation from the rest of the world, and ultimately by attacking the ports.

The methods were the same; but the purpose in one case was defensive, in the other offensive.
The confusion of the two ideas leads to much unnecessary wrangling as to the proper sphere of army and navy in coast-defence.

Passive defences belong to the army; everything that moves in the water to the navy, which has the prerogative of the offensive defence.

If seamen are used to garrison forts, they become part of the land forces, as surely as troops, when embarked as part of the complement, become part of the sea forces..