Top Menu

Without street signs and divided highways on the water, a detailed set of rules have been established to prevent boating accidents. The International Regulations for Preventing Collisions at Sea, or COLREGS as they are more often referred, is perhaps one of the most important subjects for new boaters to study. The COLREGS lay out each vessel’s responsibilities in all situations where the risk of a collision exists.

One of the most basic situations, when two vessels under power meet head on, is probably the easiest to remember but failing to act appropriately can increase the risk of danger instead of eliminating it. In the situation illustrated below, when two power-driven vessels are meeting head-on (yes, I know, they’re fish not boats), both must alter course to starboard so that they pass on the port side of the other. That’s pretty easy to remember.

In my opinion, the difficulty occurs in the situation illustrated in the next graphic where the boats are not lined up exactly but are slightly offset. What to do then? If you believe there is any risk at all of collision than you should once again alter course to starboard, and you should do so early and in an obvious way so that the other vessel understands your intentions. If you don’t believe there is a risk of collision then hold your course, do not alter your heading to port! If the other vessel did interpret the situation as dangerous and altered course to starboard as he should, steering to port would again place you on a collision course.

We have run into this situation numerous times while out on the water and even more frequently as people are zipping around in dinghies. It’s a good rule to keep in mind.


  1. In sailboat racing, often is heard the shout of, “STARBOARD” indicating that the boat is on a starboard tack and has right of way over those on a port tack. A friend of mine, who races a lot tells me he once heard the shout, “PORT – NO INSURANCE!” and everybody got out of his way.

  2. Further comment: We often invoke the unwritten ‘Gross Tonnage Rule.’ If you’re bigger ‘n me and headed for me, I don’t care who is the stand on boat, I’m gettin’ out of your way.

    • But turn to starboard when you do so, not port!

      • General Prudential Rule: You do what you gotta do to avoid a collision. (DIVE! DIVE! DIV!)

        • When I was studying for my Yachtmaster exam one of the guys in the course, who skippers a boat by profession, told the instructor that he just “get’s out of everyone’s way.” I know you know this but he didn’t, and other beginners may not too, you can’t just avoid boats by making random course changes. This post is specifically about that. In almost every situation, altering course to port when approaching a vessel head on makes the situation worse rather than better if the other guy is following the rules.

  3. Mike;

    a good topic to write about and illustrating it whih these nice graphics.
    Thank you.

    Just a note:
    your fish represent boats and they have two colours.
    Then it does not make sense that the pink colour representing either starboard or port is on opposite sides on the two fish.
    Don’t you think?

    The fish coming from the left should have the pink field on the starboard side. Or the other way around.

    Enjoy sailing ;

  4. Nothing to do with the Colregs, but thanks for spreading the word more widely. But why have you started putting the ZTC logo on all pics? Are you having copyright problems?


  5. My engines are too loud to hear you yelling starboard…..I just bring my rpm’s down to about 1400 where I make my largest wake and make a close approach and move you sailboaters ova…….Just kidding folks………most people do not monitor their vhf (my cruising grounds anyway), but that is the best way to avoid collision along with a obvious course change so the other boat sees your intent……Like you, common sense, common sense and common sense……No need to play russian roulette while on the water………..

    • We always have the VHF on, even when at anchor. The only exception is that sometimes we will turn it off at night, especially if the conditions are good (no bad weather to cause boats to drag).

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

This site uses Akismet to reduce spam. Learn how your comment data is processed.