Much also depends on the location of manufacture of the boat. A US build boat will usually have far less $$$ impact overall.
Lots depends on what your use and use location will be.
I did
purchase a boat in
BVI. My intent and use is to keep it in the
BVI area then move down islands over the next few years as schedules allow. I spend 5 to 6 months on the boat each year.
For me, I Documented the Boat (US Flagged Vessel) with USCG and paid $202 per year to Temp
import to the BVI. The
Documentation with USCG cost about $500 because I used a
service in conjunction with the closing of the
sale. Could have reduced it by doing it myself but didn't feel it was cost effective.
When you document a boat, you select a Home Port.... that is any zip code within the US as a Home Port. The boat never actually has to visit the "home Port" and many are actually totally landlocked but you can use them.
Your selection of Home Port will determine what your tax liability may be. If you never Permanently relocate the boat to the US you may find that you don't ever get a State Tax bill. It really depends on what the local enforcement actions are on taxes and collection and specific statutes. Most people I know who have done as I have report they have never been taxed by their home state as the state tax is a user fee and they are not a user in the state until they bring the boat into the state.
It may be more of a lack of a reasonable/ easy way for a state to know if you own a vehicle/ boat which is located in another location outside the state.
If your
purchasing a boat in the BVI, I would strongly recommend you consider using a closing company to assure all the documents are correct and the boat has a free title to transfer FROM the person your
buying it from. Use of their Documentation
service for Flagging as a US boat in your name is generally minimal cost and efficient.