I'm glad that I now understand that rule, because if I am PL I will know why PW is yelling at me.
And if I am ever PW, it is nice to know that I have the option of asking for room to go behind S.

But in the illustrated case, I think that for PW to try to, at that point, bear off on a reach and go behind S would be the most dangerous scenario, especially for catamarans. If you are talking safety, the safest thing for PW to do at that point is to tack -- especially, of course, in heavy air.

I know, I'm a wimp. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

P.S. I still don't understand the part about being one boat length away from the obstruction. Maybe somebody can explain that.