First, I'd say well done to the working party. A great deal of time and effort has clearly been spent, and the opportunity to openly discuss these changes well ahead of their final implementation will hopefully result in a smooth and long-lasting transition from current to new.
TR18.1(b) - Rule 18 no longer applies between boats when the boat entitled to mark-room has left the mark astern and is on a course to begin sailing the next leg, or is no longer racing.
The question of when Rule 18 is no longer applicable (mark-room having been given) has been difficult all along. I recognise the attempt to simplify the question of when Rule 18 is no longer applicable (mark-room having been given)? However, I still have a niggle, and foresee some continued confusion with TR18.1(b).
However, I'm fully open to explanations which I may have missed. Kind of just thinking aloud at this stage!
The elements of TR18.1(b) 'has left the mark astern' and 'is no longer racing' are clear and not my discussion point here. Dave clarifies this clearly in the video presentation on a couple of occasions.
The point I want to discuss is when a boat 'is on a course to begin sailing the next leg'. That is one of the two conditions for TR18 turning off during a rounding, however, it was not given much airtime in Dave's presentation. What is the practical meaning of this phrase?
Is there potential for ambiguity in this clause depending on differing interpretation of this phrase?
Reading this through I have a suspicion that the problem is the word 'and'. Any computer geeks here would read that as meaning both sides of the 'AND' must be true.
In Diagram 1
When is Yellow 'on the course to begin sailing the next leg'?
- Is it when her course is one which 'closes distance' (for a windward mark, the point her course has a downwind element; more than ninety to the wind) with the leeward mark?
- Or is it when she is settled on a downwind course?
- Or is it simply when she is sailing across the apex of the turn?
- Or is it in simply, when she has left the mark astern, that phrase just being a clarification and support of what is happens the moment the mark is astern, rather than any measurable point? In which case, possibly the word 'and' may need to be substituted with something less conditional.
- Or is it some other moment?
CA (Yellow) with a symmetrical spinnaker has delayed her rounding at Position 4 (due to a mainsheet jam?). She has left the mark astern, but still is sailing less than ninety degrees (upwind) to the wind.
CB (Blue) with an asymmetrical spinnaker spots the gap and proceeds between CA and the mark, and sets her spinnaker on a high angle to accelerate to leeward of CA. CA-Yellow wants to bear away deep to set her spinnaker but is now unable to do so due to CB's leeward overlap. She protests.
In the hearing...
- CA claims that she was still entitled to mark-room, by virtue that 'she was not on a course to begin the next leg until she was sailing downwind'.
- CB claims that the moment CA passed the apex of the turn, she was on the next leg, in which case TR18 did not apply when the mark was astern of CA.