Offshore Vessel Registration

Just registered for the site and would like some input. My firm specializes in registration in Turks and Caicos for boats. None of my clients have ever mentioned being "hassled" by state authorities or others while in the U.S flying the British flag although I am sure that all the state tax authorities know perfectly well that we are using the loophole to avoid taxes. Does anyone have any experiences? The Turks and Caicos do have a cruising agreement with the U.S.A. whereby all boats should be treated equally in either U.S or British ports. Furthermore, I know that a "self-built" boat is exempt from initial sales tax since no transaction is involved but I am also aware that Florida has a use tax and some states have personal property taxes. Would appreciate a private e-mail with any experiences within particular states where I can pass along to clients Geoff adams sam@tciway.tc