18.2 Giving Mark-Room

(a) When boats are overlapped the outside boat shall give the inside boat mark-room, unless rule 18.2(b) applies.

(b) If boats are overlapped when the first of them reaches the zone, the outside boat at that moment shall thereafter give the inside boat mark-room. If a boat is clear ahead when she reaches the zone, the boat clear astern at that moment shall thereafter give her mark-room.

(c) When a boat is required to give mark-room by rule 18.2(b), she shall continue to do so even if later an overlap is broken or a new overlap begins. However, if the boat entitled to mark-room passes head to wind or leaves the zone, rule 18.2(b) ceases to apply.

(d) If there is reasonable doubt that a boat obtained or broke an overlap in time, it shall be presumed that she did not.

(e) If a boat obtained an inside overlap from clear astern and, from the time the overlap began, the outside boat has been unable to give mark-room, she is not required to give it.