There are two different situations here. The one in the ISAF precedent which Brian raised originally where PL doesn't need to tack or alter course to avoid S but PW does - and where PW can demand water from PL to allow him to cross behind S. The other situation is where PL does have to do something to avoid S and can either bear away behind S (and must still give PW room to do the same) or can choose to hail PW for room to tack - in which case PW must give PL room to tack. PL does not have to bear away behind S even if PW wants to go that way.
The second scenario makes sense. The first one sounds like unwarranted charity. BW got hmself into that situation, and he should get himself out by tacking. It's not like he doesn't have any option.
What is scary about this whole thing is that the obstruction definition seems to be saying that all this is happening within one boat length of the "obstruction." I don't think that is even realistic for Optis, much less for catamarans. (Or maybe I am not understanding that part of the definition, since apparently I don't understand much about anything.) <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />
