So, what happens when you read back through your old copy of Aftermath! while listening to Jimmy Buffet's "I've Made This Same Album 28 Times"? If you're me, your mind starts moving in odd directions. Well, even odder directions given that it's me we're talking about... Except for Cuba, there's not all that much in the Caribbean likely to have caught a nuke had WWIII happened. Plenty of sailboats. Plenty of oil if you can find a rig that hasn't been destroyed & can figure out how to refine the stuff. Full of colorful characters even without the whole "end of civilization" thing.
Swap out those ass-less chaps and leather jacket for Bermuda shorts and a Hawaiian shirt and imagine a version of "Waterworld" that halfway makes sense. This can be played realistically or over the top.
Realistic means that life is likely to be nasty, brutish, and short. No antibiotics, no more spares for your engines, and a slow slide back to 1600's era technology as what little trade is left gets strangled due to the lack of anything resembling the policing of the sea lanes. Pirates in a realistic setting are likely to be very bad men indeed.
Over the top is more fun, and thus much more likely to be played & enjoyed. In an over the top game, it'll be perfectly acceptable to say something like, "Avast ye lubbers, I be here only for the gazzoline. Arrr!" as mohawked lunatics on Skidoos menace the residents of an isolated oil rig. Mad Max on "Talk Like A Pirate Day" and Captain Jack Sparrow with an AK-47 should be the order of the day.