33 C.F.R. § 401.51 Signaling approach to a bridge.
Title 33 - Navigation and Navigable Waters
(a) Unless a vessel's approach has been recognized by a flashing signal, the master shall signal the vessel's presence to the bridgemaster by VHF radio when it comes abreast of any of the bridge whistle signs. (b) The signs referred to in paragraph (a) of this section shall be placed at distances varying between 550 m and 2,990 m upstream and downstream from moveable bridges at sites other than lock sites. (68 Stat. 93–96, 33 U.S.C. 981–990, as amended and secs. 4, 5, 6, 7, 8, 12 and 13 of sec. 2 of Pub. L. 95–474, 92 Stat. 1471) [48 FR 20691, May 9, 1983, as amended at 49 FR 30936, Aug. 2, 1984]
Title 33: Navigation and Navigable Waters
PART 401—SEAWAY REGULATIONS AND RULES
Subpart A—Regulations
Seaway Navigation
§ 401.51 Signaling approach to a bridge.
