A couple of things.
1. Will you ever take the boat to
Europe and want to spend some time there?
2. Are you a US Citizen?
Assuming that you are a US citizen.
You can do this all yourself, you do NOT need an Agent.
In order to apply for USCG Documentation you need proof of the original German
registration AND proof that the
registration was rescinded or deleted. You also need a Bill Of
Sale notarized in accordance with the Hauge Apostille Treaty. Lastly you need the builders Certificate. Do Not send originals to the USCG. Fill out the USCG form CG-1258 and the credit card form CG-7042. Send the copies to West Virginia, check online or call and bother them everyday until you hear back.
Keep the
record of VAT paid, it may be helpful if you ever take the boat to the EU or want to sell it to someone from there. Going the USCG
route, you are effectively exporting the boat so the VAT paid status may go away and if it ever goes back to the EU they may want it again.
State registration is separate and states want tax
money. If you are staying in the
Caribbean, and getting USCG documentation but not bringing the boat to the US then you should not need to register it in any state and do not need to pay tax to the state. If you ever bring it back to the US and keep it in a particular state then they may want
taxes.
Also: register with the FCC and get a ship station
license and a restricted
radio operators
permit.