I don't get it. You're going to deliver things ONLY within Pinellas County? Seems like there wouldn't be much market, since a truck would certainly be quicker and probably a lot cheaper.
But the bottom line is that if you want to haul cargo by vessel, the Coast Guard is going to have a lot to say about your boat, your business, and your qualifications. And the state of Florida
is going to want you to have a business license
and pay business taxes
. And the federal government
is going to want all of the usual taxes
that depend on how the business is structured.
In other words, if you think you can avoid all of the hassles related to running a land-based business just by moving to a boat, you can't.
Good luck to you, in any case.