Rule 18.4 (gybing at a leeward mark) does not apply at a gate mark.

This may be the biggest “game change” in the new rules. When a leeward “gate” is being used (two leeward marks close to one another that boats pass between and exit in either direction), rule 18.4 does not apply (see rule 18.4). That means that when a boat is approaching a gate mark on the inside with right of way over other boats (and assuming that rule 17 does not apply; i.e., she did not become overlapped from clear astern which would require her to not sail above her proper course), she does not need to gybe to sail her proper course around that mark for as long as she remains the right-of-way boat. She may sail farther from the mark than needed to sail her proper course, even if she has no intention of sailing over to the other gate mark. She might do this because she is having difficulty lowering her spinnaker, or because she wants to push the outside boat outside of the zone or over to the other mark. Outside keep-clear boats will need to keep clear of her under rules 10 (port/starboard) or 11 (windward/leeward). The take-away here is, more than ever, outside boats should not have their bows “locked” outside of boats they are giving room to or keeping clear of at marks.