Problem with that is the ammo for the big guns aren't part of the ship thus would be considered 2 items. Hell, I like the destroyer idea myself. The big guns alone is enough of a scare tactic to freak any unsuspecting captain or port.
Taking a sea port with a carrier would be great. Big enough to block off a harbor. Huge enough to have enough pirate living on it for a pretty huge landing force. enough deck space for an arsenal of cannons. And if that doesn't work, drain the water cooling the nuclear reactors and wait for a meltdown then BOOOM. Scuttle the ship and you scuttle the entire caribbean.