It is correct that you can not use a foreign built boat in the USA for commercial work, and it is true that you can get an exception to the rule
The procedure for getting an excemption is to work with a member
of congress who will attach a short "rider" to a funding
bill making you boat a special case. You have to convince your member
of congress that you are a worthy cause for the work involved. It might be more difficult if you cogessional district is in Kansas, or if you live in New Zealand
and aren't likely to have an impact on the next re-election campaign.
My boat (Canadian bulit) went through this process when a previous owner bought the boat used intending to charter it and hadn't done the research
he shopuld have before the purchase
. His congressman took pity on him and attached the following statement to the annual funding
That, nothwithstanding sectrions 12105, 12106, 12107 and 12108 of title 46, United States Code, and section 7 of the Merchant Marine Act, 1920 (46 App. U.S.C. 883), as applicable on the date of this Act, the Sectratary of the department in which the Coast Guard is operating may issue a certificate of documentation for the vessel HIPPOCAMPUS, United States offical number 560934
In the final bill there are several pages of these exemptions, so it is apparently not an unusual occurance. This was done several years ago, and the vessel has been out of commercial service
for some time, but my annual Certificate of Documentation
still includes under "Entitlements" the following "Special Legislation - Coastwise, Special Legislation - Fishery".