Faith, it's a shame you didn't come back to clarify what your plans were. As it is, I see errors in each of the above replies WRT what I 'presume' your plans are.
Also, sales & use tax for boats is not administered by a State agency but rather than each county tax collector. Some of these county websites are done well, some are far less clear, and it's easy to be a bit misled even when going to your intended county's website because terms (e.g. "registration") mean different things depending on the circumstances.
There has been a lengthy discussion on this topic, originated by someone in CA who plans to come down to FL before leaving for the Caribbean, on the SSCA Discussion Board; you might find it helpful altho' this topic can quickly confuse since it isn't as simple as it might seem at first glance.