Here’s a situation that came up at the 2012 Baker Trophy – the US High-School Team Race Championship. It was at the leeward mark (Mark 3) of a digital-N course; the next leg was a beam reach toward Mark 4.
Boat A came into the zone at the leeward mark in first place, overlapped inside X and clear ahead of the rest of the fleet. A, who had luffing rights, luffed X to the edge of the zone. The plan was to hold X out until B arrived, but X was able to slow enough to jibe astern of A and turn back toward the mark. A jibed with her and sailed straight to the mark.
Meanwhile, B had sailed toward the mark, fully expecting that A would be able to hold X away long enough for B to round in first place. Caught by surprise when this didn’t happen, she failed to react quickly enough and ended up caught on starboard tack at the mark, with no mark-room. So she decided to make the best of a bad situation and jibe inside X and A, hitting X and the mark.
Imagine you’re an umpire and you manage to see all this correctly. What is your call? I’ll give you a little time to come up with your answer (though of course if you were actually an umpire you would have no time), and publish my answer in the next posting.