I believe the cruising permit
exempts you from the 90 days rule
if you come here in a boat you already own. Sort of a go to any state free arrangement only as far as taxes
. Not sure if it does apply if you purchase
here too. Should you check in with US immigration with your own boat and get the cruising permit
you get a tax free year. It might work if you bought the boat, then got the required permit ASAP. Sort of a technical issue I suppose and I would go to the horses mouth to be very sure. Can't see why it would not work. If you keep a boat in the US and are not a US citizen then no it does not count. Honor among tax collectors sort of thing.
If you haul the boat in FL and are actively working on it even a US citizen can get past the state of FL and that is no easy task. I believe you have to apply for it before hand too. With most tax issues you are guilty because they say so unless you can prove yourself innocent before they toss you in jail.