Collision avoidance — Rule 19 · Conduct of vessels in restricted visibility
Reading notes · Collision avoidance
Nobody can see anybody, so nobody stands on. Everything Section II taught you is switched off.
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What the Rule says
(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. (b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate maneuver. (c) Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with the Rules of Section I of this part. (d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided: (i) an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken; (ii) an alteration of course towards a vessel abeam or abaft the beam. (e) Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over.
COLREGs Rule 19, as published in the US Coast Guard Navigation Rules Handbook. It is a work of the United States federal government and is in the public domain.
How to read it
In or near restricted visibility you are already at a safe speed for the conditions, with your engines ready for immediate maneuver. Rule 19(b) asks that of you before any contact appears.
It applies where nobody can see anybody. This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. That is the whole condition, and it is the first thing the Rule says.
So there is no stand-on vessel, and there is no give-way vessel either. Standing on and keeping out of the way belong to Section II — the Rules for vessels in sight of one another — and Section II is not what governs you here. Everybody maneuvers.
And the order of precedence goes with it. Rules 11 to 18 are that Section, and Rule 18 is the one that ranks vessels against each other. In restricted visibility what she is decides nothing: a contact on a screen has no shapes to read and no lights to see. What decides it is which side of your beam she is on.
Section II — Rules 11 to 18 — does not apply here, and neither does the order of precedence in Rule 18. Section I — Rules 4 to 10 — still does. Rule 19(c) tells you to apply it with due regard to the visibility: look-out, safe speed, risk of collision, action to avoid collision, narrow channels and traffic separation schemes are all still in force.
Rule 19 says these alterations shall be avoided so far as possible. That is a strong steer, not an absolute bar: if nothing better is open to you, you may still have to make one — but only having weighed what it costs.
A worked encounter
One encounter, as the chapter sets it up. What follows is what each answer earns you.
No — and there is nobody here to hold for. Holding your course and speed is what a stand-on vessel does, and Rule 19 has no stand-on vessel. That answer comes from Section II — the Rules for vessels in sight of one another — and this Rule applies where nobody can see anybody. In restricted visibility everybody maneuvers. There is no ladder either: what each of you is decides nothing here, because the Rule that ranks vessels is in the Section that has stopped applying.
Rule 19. This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. That single sentence is what takes Section II out of play — and Section II is where standing on, keeping out of the way and the whole order of precedence live.
Rule 19. And what the Rule does ask of you is the opposite of holding. Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate maneuver.
Right — altering to port is what the Rule tells you to avoid. She is forward of your beam, and there the Rule names the turn outright: an alteration of course to port for a vessel forward of the beam. It is not a rule about which side she is on — it is about which side of your own beam she is on, and she is ahead of it. Rule 19 names the alterations to avoid. It does not require you to turn at all: your avoiding action may be a reduction of speed.
Rule 19. A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided: (i) an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken.
Rule 19. And the same beam decides a second thing. Forward of it, Rule 19(e) puts a speed on you as well as a helm: shall reduce her speed to the minimum at which she can be kept on her course. The beam cuts both halves of this Rule with the same cut.
No — that is the alteration Rule 19 names. The Rule does not order the other one. She is abeam or abaft your beam, on your port side. Towards her, from here, is to port — and that is what the Rule names: an alteration of course towards a vessel abeam or abaft the beam. Rule 19 names the alterations to avoid. It does not require you to turn at all: your avoiding action may be a reduction of speed.
Rule 19. A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided: … (ii) an alteration of course towards a vessel abeam or abaft the beam.
Rule 19. And the same beam decides a second thing. Abeam or abaft it, the speed half of the Rule does not attach: Rule 19(e) asks for a vessel heard apparently forward of her beam. One line, two answers.
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