Rule 18 is changed to: **18 MARK-ROOM** **18.1 When Rule 18 Applies** Rule 18 applies between boats when they are required to leave a mark on the same side and at least one of them is in the zone. However, it does not apply between a boat approaching a mark and one leaving it. Rule 18 no longer applies between boats when the boat entitled to mark-room is on the next leg and the mark is astern of her. **18.2 Giving Mark-Room** - (a) When the first boat reaches the zone, - (1) if boats are overlapped, the outside boat at that moment shall thereafter give the inside boat mark-room. - (2) if boats are not overlapped, the boat that has not reached the zone shall thereafter give mark-room. - (b) If the boat entitled to mark-room leaves the zone, the entitlement to mark-room ceases and rule 18.2(a) is applied again if required based on the relationship of the boats at the time rule 18.2(a) is re-applied. - (c) If a boat obtained an inside overlap and, from the time the overlap began, the outside boat is unable to give mark-room, rule 18.2(a) does not apply between them. **18.3 Tacking or Gybing** - (a) If mark-room for a boat includes a change of tack, such tack or gybe shall be done no faster than a tack or gybe to sail her proper course. - (b) When an inside overlapped right-of-way boat must change tack at a mark to sail her proper course, until she changes tack she shall sail no farther from the mark than needed to sail that course. Rule 18.3(b) does not apply at a gate mark or a finishing mark and a boat shall be exonerated for breaking this rule if the course of another boat was not affected before the boat changed tack.