18.4
Gybing in the Zone
When an inside overlapped right-of-way boat must gybe at a mark to sail her proper course, until she gybes she shall sail no farther from the mark than needed to sail that course. Rule 18.4 does not apply at a gate mark.
Part 2 — When Boats Meet
Section C rules do not apply between boats when the mark or obstruction referred to in those rules is a starting mark surrounded by navigable water or its anchor line, from the time the boats are approaching it to start until they have left it astern.
When an inside overlapped right-of-way boat must gybe at a mark to sail her proper course, until she gybes she shall sail no farther from the mark than needed to sail that course. Rule 18.4 does not apply at a gate mark.