33 C.F.R. § 81.5
(a) The owner, builder, operator, or agent of a vessel of special construction or purpose who believes the vessel cannot fully comply with the 72 COLREGS light, shape, or sound signal provisions without interference with its special function may apply for a determination that alternative compliance is justified. The application must be in writing, submitted to the Chief of the Prevention Division of the Coast Guard District in which the vessel is being built or operated, and include the following information:
(2) The identification of the vessel by its:
(5) A description of the provision for which the Certificate of Alternative Compliance is sought, including:
(7) A copy of the vessel's plans or an accurate scale drawing that clearly shows:
(iii) Any obstructions that may interfere with the equipment when installed in:
(b) The Coast Guard may request from the applicant additional information concerning the application.
(Approved by the Office of Management and Budget under control number 1625-0019)
[CGD 77-136, 47 FR 13799, Apr. 1, 1982, as amended by USCG-2006-25150, 71 FR 39208, July 12, 2006; USCG-2018-0874, 84 FR 30878, June 28, 2019]