The closest approximation to keeping a large naval force together, is keeping them in column; because in that formation, the ships can be made simply to "follow the leader" without signal, and act like one long, flexible body.

But the vessels of a modern fleet would make a column many miles long--a column of 20 battleships alone would be 5 miles long, and the addition of the various cruisers, destroyers, and other vessels, would make a column so long that it would be unwieldy; and if its ends were attacked, the other vessels could not come to their relief.

Besides, the duties of battleships, battle cruisers, scouts, destroyers, and submarines, are distinct--with the result that, as in land operations, bodies of the various types operate separately and apart from those of other types.
Not only, also, do the various types operate separately, but often the necessities of a case demand that a certain number--say of battleships--be sent away from the main body on some mission; or that a certain number of destroyers be sent away from the main body of destroyers.
Any such diversion entails a danger that is sometimes great, and sometimes small; but such diversions and risks cannot be avoided, and should not be avoided when they are necessary, any more than a man should avoid going out of doors, though that act always entails some danger.

Suppose, for instance, that in the operations of a war carried on in the Caribbean, the Navy Department should get trustworthy information that the enemy had detailed 3 battle cruisers to speed north and bombard New York.

The department would probably have to detach a force from the fleet and send it north, to prevent the bombardment.