Question
When Y enters the zone of a leeward mark B and Y are overlapped on starboard tack with Y inside. Y is subject to rule 17. After position 3, Y gybes to round the mark. B gybes at the same time into an overlap outside of Y. As Y is passing the mark, B luffs her above the course to the next mark. Y responds promptly and keeps clear. There is a protest. What should the call be?

Answer
No penalty.

When Y enters the zone she is overlapped inside B and rule 18.2(b) requires B to give Y mark-room thereafter. Y is entitled to room to round the mark as necessary to sail the course. This is the room Y needs to comply with rule 28 and, after she gybes, she sails within this mark-room. B gives Y this room and room for Y to keep clear as required by rule 16.1. B breaks no rule.