(a) Except as allowed in paragraph (c) of this section, a State numbering system must require the numbering of vessels to which § 173.11 of this chapter applies.
(b) A State numbering system may require the numbering of any vessel subject to the jurisdiction of the State unless prohibited by the regulations in Part 173 of this chapter.
(c) A State numbering system may exempt from its numbering requirements any vessel or class of vessels to which § 173.13 of this chapter applies.