33 USC 1605 - Navy and Coast Guard vessels of special construction or purpose

(a) Certification for alternative compliance 
Any requirement of the International Regulations with respect to the number, position, range, or arc of visibility of lights, with respect to shapes, or with respect to the disposition and characteristics of sound-signaling appliances, shall not be applicable to a vessel of special construction or purpose, whenever the Secretary of the Navy, for any vessel of the Navy, or the Secretary of the department in which the Coast Guard is operating, for any other vessel of the United States, shall certify that the vessel cannot comply fully with that requirement without interfering with the special function of the vessel.
(b) Closest possible compliance by vessels covered by certification for alternative compliance 
Whenever a certification is issued under the authority of subsection (a) of this section, the vessel involved shall comply with the requirement as to which the certification is made to the extent that the Secretary issuing the certification shall certify as the closest possible compliance by that vessel.
(c) Publication of certifications in Federal Register 
Notice of the certifications issued pursuant to subsections (a) and (b) of this section shall be published in the Federal Register.
(d) Issuance of certification for a class of vessels 
A certification authorized by this section may be issued for a class of vessels.