If the Secretary decides that the application of a provision of part B, C, F, or G of this subtitle is not necessary in performing the mission of the vessel engaged in excursions or an oceanographic research vessel, or not necessary for the safe operation of certain vessels carrying passengers, the Secretary by regulation may—

(1) for a vessel, issue a special permit specifying the conditions of operation and equipment;

(2) exempt an oceanographic research vessel from that provision under conditions the Secretary may specify;

(3) establish different operating and equipment requirements for vessels defined in section 2101(53)(A) of this title; and

(4) maintain different structural fire protection, manning, operating, and equipment requirements for vessels that satisfied requirements set forth in the Passenger Vessel Safety Act of 1993 (Public Law 103-206) before June 21, 1994.