(a)General.(1) The operator of each vessel requesting a drawbridge to open shall signal the drawtender and the drawtender shall acknowledge that signal. The signal shall be repeated until acknowledged in some manner by the drawtender before proceeding.(2) The signals used to request the opening of the draw and to acknowledge that request shall be sound signals, visual signals, or radiotelephone communications described in this subpart.(3) Any of the means of signaling described in this subpart sufficient to alert the party being signaled may be used.(b)Sound signals.(1) Sound signals shall be made by whistle, horn, megaphone, hailer, or other device capable of producing the described signals loud enough to be heard by the drawtender.(2) As used in this section, "prolonged blast" means a blast of four to six seconds duration and "short blast" means a blast of approximately one second duration.(3) The sound signal to request the opening of a draw is one prolonged blast followed by one short blast sounded not more than three seconds after the prolonged blast. For vessels required to be passed through a draw during a scheduled closure period, the sound signal to request the opening of the draw during that period is five short blasts sounded in rapid succession.(4) When the draw can be opened immediately, the sound signal to acknowledge a request to open the draw is one prolonged blast followed by one short blast sounded not more than 30 seconds after the requesting signal.(5) When the draw cannot be opened immediately, or is open and shall be closed promptly, the sound signal to acknowledge a request to open the draw is five short blasts sounded in rapid succession not more than 30 seconds after the vessel's opening signal. The signal shall be repeated until acknowledged in some manner by the requesting vessel.(c)Visual signals.(1) The visual signal to request the opening of a draw is-(i) A white flag raised and lowered vertically; or(ii) A white, amber, or green light raised and lowered vertically.(2) When the draw can be opened immediately, the visual signal to acknowledge a request to open the draw, given not more than 30 seconds after the vessel's opening signal, is- (i) A white flag raised and lowered vertically;(ii) A white, amber, or green light raised and lowered vertically; or(iii) A fixed or flashing white, amber, or green light or lights.(3) When the draw cannot be opened immediately, or is open and must be closed promptly, the visual signal to acknowledge a request to open the draw is- (i) A red flag or red light swung back and forth horizontally in full sight of the vessel given not more than 30 seconds after the vessel's opening signal; or(ii) A fixed or flashing red light or lights given not more than 30 seconds after the vessel's opening signal.(4) The acknowledging signal when the draw cannot open immediately or is open and must be closed promptly shall be repeated until acknowledged in some manner by the requesting vessel.(d)Radio telephone communications.(1) Radiotelephones may be used to communicate the same information provided by sound and visual signals.(2) The vessel and the drawtender shall monitor the frequency used until the vessel has cleared the draw.(3) When radiotelephone contact cannot be initiated or maintained, sound or visual signals under this section shall be used.CGD 82-025, 49 FR 17452, Apr. 24, 1984, as amended by CGD 82-025, 50 FR 11366, Mar. 21, 1985; CGD 84-022, 51 FR 16308, May 2, 1986; CGD 96-026, 61 FR 33664, June 28, 1996; USCG-2001-10881, 71 FR 70308, Dec. 4, 2006