Before I discuss that presentation any further, I have to tell you that the opinions expressed there are mine and mine alone. I did not consult the US Sailing Racing Rules Committee before preparing it, nor did any committee of US Sailing review it before it was posted. Having said that, I think the overall message of the presentation is correct, and the presentation could form the basis for a club or regional clinic on changes to the Racing Rules of Sailing. If you agree, please feel free to download it and use it. All I ask is that you not edit it or change it in any way (other than to skip over slides).
But that's not what I want to write about here. The subject of this posting is Slide 8, entitled 'Implication of “Proper Course” in Rule 18.2(c)(2)', which features the following animation:
On the right of this animation I wrote, "Here, Blue breaks rule 16.1, Changing Course, and is not exonerated because she is not taking mark-room under rule 18.2(b), nor room to sail her proper course under rule 18.2(c)(2)."
At the time, I thought this was clear; but several e-mails from sailors have convinced me that it's not. Here's what I was trying to say and to illustrate in the animation.
First, we all agree that Blue is entitled to mark-room under rule 18.2(b) because she was clear ahead when she entered the zone. This means she is entitled to room to leave the mark on its required side (in this case, to port), room to sail to the mark as long as her proper course is to sail close to it and room to round the mark as necessary to sail the course (see Definition Mark-room at the beginning of the 2013-2016 rulebook).
Just after position 3, Yellow becomes overlapped inside Blue, so rule 18.2(c)(2) kicks in. That rule says, "When [Yellow] is required to give [Blue] mark-room by rule 18.2(b), ... if she becomes overlapped inside [Blue], she shall also give [Blue] room to sail her proper course while they remain overlapped."
Now let's look at position 4 in the animation. What is Blue's proper course from that point on? To answer that question we need to remove Yellow from the diagram (see Definition Proper Course). In the absence of Yellow, what course would Blue take to finish the race as quickly as possible? Well, there may be other boats in the fleet, and Blue might want to take a high line so maybe she would luff up as shown in the animation -- but I don't think so. Starting from her deep position 4, she has no hope of luffing up high enough to get above the line of other boats rounding the mark -- after all, they will have luffed up slightly, too, and starting from a position much further to windward. If Blue luffs up as shown, all she will accomplish is to bring herself almost to a stop and then be in the backwind of all the boats who have already rounded the mark ahead of her. So in my opinion Blue's proper course is to trim in onto a closehauled course and make the best of her poor rounding.
At least, that's what I hoped I had conveyed in the animation, but apparently not. I concede it's not obvious. Dick Rose, in his rules column in Sailing World, says, "[The boat entitled to room] can luff, even above closehauled on port tack, to shut the door on [the other boat]." If I were to do the presentation again, I would picture Blue head-to-wind at position 5 to emphasize that she is clearly not on her proper course.
Suppose you concede that Blue is not sailing her proper course between positions 4 and 5. What is she entitled to do under rule 18, that Yellow is not allowing her to do? Blue had the opportunity to sail to the mark and chose not to do so, and at position 4 she has already rounded the mark as required to sail the course (i.e., turned to a close-hauled course). So Yellow only needs to allow Blue to leave the mark astern on her port side, and although that hasn't happened yet at position 5, it's clear that Yellow is complying with that requirement -- instead of luffing up, Blue could trim in and quickly leave the mark astern.
Therefore, the events between positions 4 and 5 are governed entirely by rules 11 (Windward/Leeward) and 16, Changing Course.
Blue has right of way, and clearly Yellow fails to keep clear of her. So, why not penalize Yellow under rule 11? Well, rule 16.1 says, "When a right-of-way boat changes course, she shall give the other boat room to keep clear." New Definition Room says that room includes "space to comply with her obligations under the rules of Part 2 and rule 31 ...". Because Blue's change of course forces Yellow to hit the mark, Blue did not give Yellow room to comply with her obligations under rule 31. Therefore Blue breaks rule 16.1 and Yellow is exonerated for breaking rules 11 and 31 because Blue's illegal change of course caused her to do so.
So Blue should take her turns.
I hope this clears up the issues sailors may have with Slide 8 of my presentation at the AGM.