The following information is from Rule 34 - Manoeuvring and Warning Signals.

When vessels are in sight of one another, a power-driven vessel underway, when manoeuvring as authorized or required by these Rules, shall indicate that manoeuvre by the following signals on her whistle:

— one short blast to mean “I am altering my course to starboard”,

— two short blasts to mean “I am altering my course to port”,

— three short blasts to mean “I am operating astern propulsion”.

These signals may be supplemented by light signals of one, two, or three flashes, repeated as appropriate during the manoeuvre. 

A vessel that is in doubt about another vessels intentions or attention to COLREGS or intention to avoid collision shall immediately indicate such doubt by giving at least five short and rapid blasts on the whistle. Such signal may be supplemented by a light signal of at least five short and rapid flashes. This can be synchronized with the blasts so it will be clear which vessel is signaling.

When a vessel plans to overtake another:

— two prolonged blasts followed by one short blast to mean “I intend to overtake you on your starboard side”,

— two prolonged blasts followed by two short blasts to mean “I intend to overtake you on your port side”,

The vessel being overtaken should indicate agreement by sounding:

— one prolonged blast, one short blast, one prolonged blast, and one short blast, in that order

These whistle sounds are rarely heard around Comox harbour. Casual manoeuvres do not require these signals. They are to be used "when manoeuvring as authorized or required by these Rules". The general practice of pleasure boaters is that, when there is no risk of collision (hence no requirement to conform to the rules), vessels can manoeuvre as they wish and need not make signals. Commercial vessels may use sound signals more frequently than pleasure boaters. 

Any of these signals may be reinforced by flashing lights if the sound signals have apparently not been noticed. See Rule 34 for details.

The above signals should be used only when vessels are in sight of one another. In conditions of restricted visibility there are other signals that should be used instead. 

A vessel should sound one prolonged blast when approaching a blind corner. If a vessel hears such a blast at the blind corner, she should sound one in return to alert the first vessel of her presence.

A power-driven vessel of 12 metres or more in length that is leaving a dock or berth shall give a signal of one prolonged blast. (Some frequently operating ferries may be exempt from this requirement under certain conditions.)

Last modified: Saturday, 8 February 2025, 3:51 PM