To be clear...dont get hung up with Jones act...just check the requirements for Uninspected Vessel requirements if all you are looking at is taking up to 6 passengers.
The definition is uninspected vessels for 6 passengers or less but there is still a laundry list of requirements the USCG requires ( country of origin for the vessel included)..... most USCG district's have a pamphlet or book that lists the requirements and CFRs that require them.
https://www.google.com/url?sa=t&sou...FjAAegQIARAB&usg=AOvVaw2fi1KNLRZWU8du9SoXCqq9
" More than 5 Net Tons less than 100 Gross Tons:
Documented with Coast Guard. Endorsed for "coastwise trade".
Must be U.S. built and U.S. owned."
However, exemptions may be granted if I remember correctly.