Gybing at the leeward mark

The situation

Inside and overlapped at the leeward mark, Kira needs to gybe to head off down the next leg. She starts to swing wide to set up a smooth gybe.

The question

How much room does the inside boat get to gybe?

The ruling

Mark-room includes room to gybe when a gybe is part of her proper-course rounding — but rule 18.4 limits her: until she gybes, an inside overlapped right-of-way boat must sail no farther from the mark than needed to sail her proper course. So Kira can't swing out wide 'to set up' the gybe and push the outside boat around; she stays tight on her proper-course track and gybes at the mark. 'In wide, out tight' still rules. (Note rule 18.4 doesn't apply at a gate mark.)