The Racing Rules of Sailing
RRS 17 and sailing below proper course on a downwind leg
After several weeks of heated debate among fellow judges — all far more experienced than I, but no less stubborn for it — we have agreed to refer the matter to a higher authority.
In the attached diagram, assume that blue is L and yellow is W. Both boats (one-design) are on a downwind leg, approaching the leeward mark, and their proper course is about 135° TWA.
L became overlapped to leeward of W from clear astern, so RRS 17 applies.
The question is this:
If L bears away to 180 degrees to the true wind — dead downwind — without gybing, is L sailing above her proper course for the purposes of RRS 17?
My understanding is that RRS 17 only prevents L from sailing above her own proper course, not below it. And I believe it is generally accepted that sailing at 180 degrees to the true wind is sailing below, not above, than sailing at 135 degrees to the true wind. So, in principle, L should be allowed to bear away and sail dead downwind without gybing.
In other words, Rule 17 is not a general rule against L making life difficult for W. It is narrower than that. When it applies, it prevents L from sailing above her own proper course. It does not require L to sail exactly on that course, and it does not prevent her from sailing below it.
We would be curious to hear whether the forum agrees with this reading, or whether there is a rule I am overlooking that would lead to a different conclusion.
Created: Yesterday 18:19
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100 WIND
2026-05-19
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Al Sargent
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Only sailing above a proper course is restricted.
Why here would the windward boat think of complaining?
The problem is that, if the orange line in the diagram represents the best course, there being no other factors, then L should have gybed and headed for the mark at about 5.5. At position 6 she is sailing above her proper course (which is to sail to the mark) and a protest should result in her being penalised. That said there is a considerable difference between a diagram with nice lines on it and what you will hear in the protest room. Judging gybing angles is one of the more difficult things that Umpires have to do on the water.
Id want to see B holding Y out for another boat length or so before I penalised B.
In a hearing B is going to say she never got beyon @5 and Y will say B was @7. Last point of certainty B was not sailing above her proper course.
If nigel is correct, that is the relevant rule.
Side note ... the moment blue were to gybe, then they are on opposite tacks and 17 no longer applies.
The same question could be posed going upwind and two overlapped port tack boats reach the starboard layline (Assume 17 applies). At some point the proper course for L is to be on the other tack (starboard). So, could the leeward port tack body sail up to "head to wind" because their proper course is to be on the other tack?
And I think the answer is that once you are at/past the point where your proper course is to gybe (you've reached the layline), then you must do so. Upon gybing, rule 17 stops and other rules will switch.
For going upwind, the leeward boat gets to luff to "head to wind" if they like and try to force windward to tack (once they reach the layline)
The issue I raised is: When is it your proper course to gybe? My argument was that even in absence of another boat it may have been advantageous for blue to deliberately sail high of the layline in order to maintain speed and momentum through the gybe on the final approach to the mark. This would define Blue's proper course, not what Yellow may have thought (which is clearly "gybe when you get to the layline")
Yellow, of course would say "no, he wanted to take me up so he could show me his transom with no overlap at the circle". But if blue doesn't alter course at position 4 as I suggested earlier, the argument from Yellow would be weaker.
We are in Case 75 territory. Though Case 75 is based upon 18.4 and not 17 ... the idea is that the leeward ROW boat's proper course can include a "tactical rounding" depending upon the circumstances.
Judges should be guessing about boats' tactical intentions.
17 ON THE SAME TACK; PROPER COURSE
By bearing away, she is not promptly sail astern of the other boat, so bearing away is not forbidden. Only rule 10 applies.
I wouldn't go as far as 'heart of proper course.'