33 CFR § 173.1 - Purpose; preemptive effect.
---
identifier: "/us/cfr/t33/s173.1"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "33 CFR § 173.1 - Purpose; preemptive effect."
title_number: 33
title_name: "Navigation and Navigable Waters"
section_number: "173.1"
section_name: "Purpose; preemptive effect."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "S"
subchapter_name: "BOATING SAFETY"
part_number: "173"
part_name: "VESSEL NUMBERING AND CASUALTY AND ACCIDENT REPORTING"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "31 U.S.C. 9701; 46 U.S.C. 2110, 6101, 12301, 12302; OMB Circular A-25; DHS Delegation No. 00170.1, Revision No. 01.4."
regulatory_source: "CGD 72-54R, 37 FR 21399, Oct. 7, 1972, unless otherwise noted."
cfr_part: "173"
---
# 173.1 Purpose; preemptive effect.
This part prescribes requirements for numbering vessels and for reporting casualties and accidents to implement sections 6101, 6102, 12301, and 12302 of Title 46, United States Code. 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.
[USCG-2003-14963, 77 FR 18699, Mar. 28, 2012]