46 CFR § 175.110 - General applicability.
(a) Except as in paragraph (b) of this section, this subchapter applies to each vessel of less than 100 gross tons that carries 150 or less passengers, or has overnight accommodations for 49 or less passengers, and that -
(1) Carries more than six passengers, including at least one for hire;
(2) Is chartered with a crew provided or specified by the owner or the owner's representative and is carrying more than six passengers;
(3) Is chartered with no crew provided or specified by the owner or the owner's representative and is carrying more than 12 passengers; or
(5) Is a ferry carrying more than six passengers.
(b) This subchapter does not apply to:
(1) A vessel operating exclusively on inland waters that are not navigable waters of the United States;
(2) An oceanographic research vessel;
(4) A vessel of a foreign country that is a party to the International Convention for the Safety of Life at Sea, 1974, as amended (SOLAS), to which the United States Government is currently a party, and that has on board a current valid SOLAS Passenger Ship Safety Certificate; or
(5) A vessel of a foreign country, whose government has inspection laws approximating those of the United States and that by its laws accords similar privileges to vessels of the United States, which has on board a current valid certificate of inspection, permitting the carrying of passengers, issued by its government.