This part establishes a standard numbering system for vessels and a uniform vessel casualty reporting system for vessels by prescribing requirements applicable to the States for the approval of State numbering systems. The regulations in subparts A, B, and D of this part have preemptive effect over conflicting State or local regulation. The regulations in subpart C of this part have preemptive effect over State or local regulation within the same field, except to the extent that Congress requires the Coast Guard to allow State casualty reporting systems pursuant to 46 U.S.C. chapter 131.