[QUOTE=CCIP;2309216]It's a handy way of thinking of it
Another way of thinking about it is captain vs. admiral - in many situations, you might have both on board a ship, as for example in the Bismarck's last fight. In normal circumstances, there is clear division of who does what - the admiral makes operational decisions, but tactics are for captains to handle.
That's because the Captain is in command of the ship while the Admiral is in command of the fleet.
Ever wonder why they call it "the flag ship"? In the days before radio, the ship in charge gave orders with signal flags. It had to be so positioned within the fleet so that all the other ships could see it, and its flags, so they'd know what to do. Took me many years to get it. I always thought it was a flagship because the Admiral flew his own personal flag from it. Not entirely true, as it turned out...