(a) Vessels excepted
The provisions of this part shall not apply to—

(1) A ship of war;

(2) A ship of the United States belonging to and operated by the Government, except a ship of the Maritime Administration of the Department of Transportation, the Inland and Coastwise Waterways Service, or the Panama Canal Company;

(3) A foreign ship belonging to a country which is a party to any Safety Convention in force between the United States and that country which ship carries a valid certificate exempting said ship from the radio provisions of that Convention, or which ship conforms to the radio requirements of such Convention or Regulations and has on board a valid certificate to that effect, or which ship is not subject to the radio provisions of any such Convention;

(4) Yachts of less than six hundred gross tons not subject to the radio provisions of the Safety Convention;

(5) Vessels in tow;

(6) A ship navigating solely on any bays, sounds, rivers, or protected waters within the jurisdiction of the United States, or to a ship leaving or attempting to leave any harbor or port of the United States for a voyage solely on any bays, sounds, rivers, or protected waters within the jurisdiction of the United States;

(7) A ship navigating solely on the Great Lakes of North America and the River Saint Lawrence as far east as a straight line drawn from Cap des Rosiers to West Point, Anticosti Island, and, on the north side of Anticosti Island, the sixty-third meridian, or to a ship leaving or attempting to leave any harbor or port of the United States for a voyage solely on such waters and within such area;

(8) A ship which is navigated during the course of a voyage both on the Great Lakes of North America and in the open sea, during the period while such ship is being navigated within the Great Lakes of North America and their connecting and tributary waters as far east as the lower exit of the Saint Lambert lock at Montreal in the Province of Quebec, Canada.

(b) Radio station unreasonable or unnecessary
Except for nuclear ships, the Commission may, if it considers that the route or the conditions of the voyage or other circumstances are such as to render a radio station unreasonable or unnecessary for the purposes of this part, exempt from the provisions of this part any ship or class of ships which falls within any of the following descriptions:

(1) Passenger ships which in the course of their voyage do not go more than twenty nautical miles from the nearest land or, alternatively, do not go more than two hundred nautical miles between two consecutive ports;

(2) Cargo ships which in the course of their voyage do not go more than one hundred and fifty nautical miles from the nearest land;

(3) Passenger vessels of less than one hundred gross tons not subject to the radio provisions of the Safety Convention;

(4) Sailing ships.

(c) Unforeseeable equipment failures
If, because of unforeseeable failure of equipment, a ship is unable to comply with the equipment requirements of this part without undue delay of the ship, the mileage limitations set forth in paragraphs (1) and (2) of subsection (b) shall not apply: Provided, That exemption of the ship is found to be reasonable or necessary in accordance with subsection (b) to permit the ship to proceed to a port where the equipment deficiency may be remedied.

(d) Radio direction finding apparatus unreasonable or unnecessary
Except for nuclear ships, and except for ships of five thousand gross tons and upward which are subject to the Safety Convention, the Commission may exempt from the requirements, for radio direction finding apparatus, of this part and of the Safety Convention, any ship which falls within the descriptions set forth in paragraphs (1), (2), (3), and (4) of subsection (b) of this section, if it considers that the route or conditions of the voyage or other circumstances are such as to render such apparatus unreasonable or unnecessary.