Rule 16.1 ON or OFF?

When a boat enters the two BL zone clear ahead, it becomes the right of way boat. As long a she doesn't pass head to wind, she stays right of way boat, provided that BOTH boats are still rounding or passing the mark. Last years' Rapid Response Match Racing Call 2007/02 was about this issue. Even gybing in front of the trailing boat doesn't have an effect of who's right of way, as long as the latter is still passing the mark. An inside starboard boat does NOT become r-o-w boat.

So rule 18.2(c) is in effect and therefore rule 18.2(d) applies to the boat with r-o-w. RRS 18.2(d) switches rule 16.1 off, for that boat. Are you still with me?
What this does is: If you round the mark as a right of way boat, you don't have to worry about giving the other boat room, when you change course. You can change course as fast as you like, the other boat has to keep clear. But only for the course change needed to round the mark. If you suddenly go another way, 16.1 is still in effect. It is reasonable to expect the other boat to know which way you go round the mark, but not, if you don't do that.

The question we've been discussing in the umpire team at Calpe was:
When is rule 18.2(d) switched off, and therefore rule 16.1 back on?
Can the r.o.w. boat, for instance, luff all the way up to head to wind as fast as she pleases? If she does so immediately after rounding? I've made up a diagram to clarify:


If the leading boat can do this in match racing, she can lay a very effective trap for the trailing boat. Without a little 'protection' from rule 16.1, the latter barely has a change to keep clear.

When does 18.2(d) no longer apply?
Firstly, RRS 16.1 is back on, when RRS 18.2(c) is off. When both boats have passed the mark. In our situation that is when the trailing boat has passed the mark. From then on the leading boat can no longer change course without giving room to the other, to keep clear.

Is there a moment that, even with RRS 18.2(c) still on, the leading boat is no longer rounding or passing the mark, and therefore subject to 16.1?
Our discussion this was never really resolved. In these issues there's always the strict interpretation of the rule and an interpretation of what is fair and the rule perhaps should be. Calls are made from such issues.

In my own solution I came up with the idea to find an 'objective' criteria. Something that can be measured, if you like, and is repeatable for everyone. This is what I came up with:
Draw a line from the rounding mark to the next mark. Then draw a line perpendicular to that line. If the leading boat is pointing below that last line, she's still rounding that mark, if she pointing above that line - in effect going back to the mark just rounded - she's no longer rounding or passing the mark.


All luffing up, towards that line, are without rule 16.1, but if she luffs further - above that line - then 16.1 is back on and she should give the trailing boat room to keep clear. This also consistent with the recently published RR Team Race Call 2008/001.

Let me be perfectly clear. At this moment the rule does not say this. Rule 18.2(c) stays on, as long as both boats haven't passed the mark. Period.
It is up to the umpires to decide if the leading boat is still subject to 16.1 or not.

What is your opinion?