33 CFR § 64.06 - Definition of terms.

---
identifier: "/us/cfr/t33/s64.06"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "33 CFR § 64.06 - Definition of terms."
title_number: 33
title_name: "Navigation and Navigable Waters"
section_number: "64.06"
section_name: "Definition of terms."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "C"
subchapter_name: "AIDS TO NAVIGATION"
part_number: "64"
part_name: "MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "14 U.S.C. 503; 33 U.S.C. 409; 42 U.S.C. 9118; 43 U.S.C. 1333; 46 U.S.C. 70034; Department of Homeland Security Delegation No. 0170.1."
regulatory_source: "CGD 78-156, 48 FR 11267, Mar. 17, 1983, unless otherwise noted."
cfr_part: "64"
---


# 64.06 Definition of terms.

As used in this part:

*Hazard to navigation* means an obstruction, usually sunken, that presents sufficient danger to navigation so as to require expeditious, affirmative action such as marking, removal, or redefinition of a designated waterway to provide for navigational safety.

*High seas* means those waters described in § 2.32(c) of this chapter.

*Markings* means the lights and other signals placed on or near structures, sunken vessels, and other obstructions for the protection of navigation.

*Navigable waters of the United States* means those waters described in § 2.36(a) of this chapter, specifically including the waters described in § 2.22(a)(2) of this chapter.

*Obstruction* means anything that restricts, endangers, or interferes with navigation.

*Structures* means any fixed or floating obstruction, intentionally placed in the water, which may interfere with or restrict marine navigation.

[CGD 78-156, 48 FR 11267, Mar. 17, 1983. Redesignated and amended by CGD 91-031, 57 FR 43402, Sept. 21, 1992; USCG-2001-9044, 68 FR 42601, July 18, 2003; USCG-2007-27887, 72 FR 45902, Aug. 16, 2007]