COLREG - Manoeuvring and Warning Signals (Rule 34)

Sound and light signal pattern for intended manoeuvres or warnings per COLREG Rule 34.

COLREGRule 34Manoeuvring signalsWarning signals

Situation

Sound signal: One short blast (~1 sec)

Light signal (optional): One all-round white flash

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Formula, assumptions, limits

COLREG Rule 34 prescribes sound signals for manoeuvres in sight of one another and for warnings. Signals may be supplemented by all-round white light flashes synchronised with the sound. Short blast = approximately 1 second; prolonged blast = 4 to 6 seconds.

Manoeuvring and warning signals

SituationSoundLightRule

Altering to starboardOne short blastOne flash34(a)(i) Altering to portTwo short blastsTwo flashes34(a)(ii) Operating engines asternThree short blastsThree flashes34(a)(iii) Narrow channel - overtake on stbdTwo prolonged + one shortn/a34(c)(i) Narrow channel - overtake on portTwo prolonged + two shortn/a34(c)(i) Narrow channel - agreementOne prolonged, one short, one prolonged, one shortn/a34(c)(ii) Doubt - in dangerFive or more short rapid blastsFive or more flashes34(d) Bend or obstructionOne prolonged blastn/a34(e)

In short

Sound and light signal pattern per COLREG Rule 34.

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