The second situation (below) involved Leo and Lena, who were approaching the windward mark on port tack. Leo was clear ahead when he reached the zone. He sailed a small distance past the layline and tacked onto starboard. A second or so later, Lena, seeing that Leo had overstood, tacked onto starboard into an inside overlap under Leo. Lena kept clear while she tacked and never caused Leo to sail above closehauled. Leo hailed to Lena that she had no right to room and he bore off at Position 3, forcing Lena to hit the mark to avoid him.

Here’s how the rules apply to Leo and Lena. Until Leo passed hear to wind, just before Position 2, he was a clear ahead boat with right of way under Rule 12 and, from the time he entered the zone until he passed head to wind, he was entitled to mark-room under Rule 18.2(b)’s second sentence. When Leo passed head to wind, Rule 18.2(b) ceased to apply (see Rule 18.2(c)), and then the boats were approaching the mark on opposite tacks. When Lena passed head to wind she became subject to Rule 13 in the zone, and at that moment Rule 18.3 began to apply. Lena completed her tack without causing Leo to take any avoiding action, and so she did not break Rule 13. After Lena was on a closehauled course, she became the right-of-way boat under Rule 11. Leo had plenty of room to keep clear and so Lena complied with Rule 15. Lena never caused Leo to sail above closehauled, nor did she prevent him from passing the mark on the required side. So she did not break Rule 18.3. Because Rule 18.3 applied, Rule 18.2(a) did not and, therefore, Lena was not entitled to mark-room. But Leo was required by Rule 11 to keep clear. By forcing Lena to bear off, Leo broke Rule 11 and, in so doing, he compelled Lena to break Rule 31 by touching the mark. Under Rule 64.1(c), Lena is exonerated for breaking Rule 31. The bottom line is that Leo should be disqualified for breaking Rule 11.