COLREG Rule 34 Warning Signals for Vessels In Sight Of Each Other

Extract from RULE 34 Manoeuvring and warming signals

(a) When vessels are in sight of one another, a power-driven vessel underway, when  maneuvering as authorized or required by these Rules, shall “1le that manoeuvre by the following signals on her whistle:

one short blast to mean “1 am altering my course to starboard”;

two short blasts to mean “l am altering my course to port”;

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

(b) Any vessel may supplement the whistle signals prescribed in paragraph (a) of this Rule by light signals, repeated as appropriate, whilst the manoeuvre is being carried out:

(i) these light signals shall have the following significance:

one flash to mean ‘1 am altering my course to starboard“;

two flashes to mean “I am altering my course to port“;

three flashes to mean ‘I am operating astern propulsion“;

(ii) the duration of each flash shall be about one second, the interval between flashes shall be about one second, and the interval between successive signals shall be not less than ten seconds;

(iii) the light used for this signal shall, if fitted, be an all-round white light, visible at a minimum range of 5 miles, and shall comply with the provisions of Annex I to these Regulations.

(7) If whistles are fitted on a vessel at a distance apart of more than 100 meters, one whistle only shall be used for giving maneuvering and warning signals.


Extract from Annex 1

Manoeuvrlng light

Not withstanding the provisions of paragraph 2 (f) of this Annex the maneuvering light described in Rule 34 (b) shall be placed in the same fore and aft vertical plane as the masthead light or lights and. where practicable. at a minimum height of 2 meters vertically above the forward masthead light. provided that it shall be carried not less than 2 meters vertically above or below the after masthead light. On a vessel where only one masthead light is carried the maneuvering light, it fitted. shall be carried where it can best be seen. not less than 2 meters vertically apart from the masthead light.