This is the situation.

The leeward mark has to be rounded to starboard and there are two boats approaching it, one on port and one on starboard, and the two boats are dead level. The boat on STARBOARD must give the boat on PORT room to round the mark inside (no that isn't a typo - that is exactly what I meant!).

Here is the reasoning.

The port tack boat has an overlap on the starboard tack boat (boats are overlapped when neither is clear astern so they've been overlapped for as long as they've been on their respective courses). 18.2(a) says the port tack boat has to be given room to round the mark. Rule 10 (On opposite tacks) does not apply because section C rules take precedence where they conflict with those in section A. Rule 18.1 says rule 18 does not apply when boats are on opposite tacks, but ONLY when one boat has to TACK to round the mark.

So the port tack boat can call for room to gybe around the mark inside the starboard tack boat and the starboard tack boat must give room. The port tack boat must gybe around the mark and is not allowed to sail past (18.4).

When I read this I found it quite alarming. I think it would be a brave port tack boat indeed that would attempt to call for room in this case. In the case of cats flying spinnakers the two boats would be closing very-very fast and the potential for massive collisions is very high. Another reason for race committees NOT to run starboard hand courses!

I've read and re-read this and I really can't believe this is what the ISAF intended. So where is the flaw in my reading of the rules? Please tell me I'm wrong