Rules of the Road · Maneuvering & Warning Signals

A vessel in a narrow channel hears one prolonged blast, one short blast, one prolonged blast, and one short blast from a vessel ahead. What does this signal mean under Rule 34?

Explanation

Rule 34(c)(ii): the vessel being overtaken, if she agrees with the proposed maneuver, sounds one prolonged, one short, one prolonged, and one short blast in that order (Morse 'C' — Charlie — meaning agreement/affirmative). The signal conveys agreement only; the side of overtaking was specified by the overtaking vessel's earlier signal under Rule 34(c)(i)/Rule 9(e). If she does not agree or is unsure, she sounds the danger signal of five or more short blasts.

Authority: 72 COLREGS Rule 34(c)(ii)

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