[Code of Federal Regulations] [Title 33, Volume 1] [Revised as of July 1, 2005] From the U.S. Government Printing Office via GPO Access [CITE: 33CFR64.06] [Page 153] TITLE 33--NAVIGATION AND NAVIGABLE WATERS CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PART 64_MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS --Table of Contents Subpart A_General Sec. 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. 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 Sec. 2.36(a) of this chapter, specifically including the waters described in Sec. 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]