Here’s a good Q&A from World Sailing – But to understand the answer, it really helps if you understand the rules, words and definitions that the Answer uses – so we’ve added them below the answer.
Q&A 2020.009 30 March 2020
The finishing line is between two marks. Boats are finishing downwind.
Does rule 18.4 apply to an inside overlapped right-of-way boat approaching the finishing line?
Rule 18.4 will apply provided that the inside overlapped right-of-way boat must gybe to sail her proper course. A finishing line is not a gate; a string representing the boat’s track, when drawn taut, is not required to pass between the marks of a finishing line. See definition Finish and rule 28.2(c).
Rule 18.4 (this is part of mark-room)
When an inside overlapped right-of-way boat must gybe at a mark to sail her proper course, until she gybes she shall sail not further from the mark than needed to sail that course. Rule 18.4 does not apply at a gate mark.
a. pass each mark on the required side and in the correct order,
b. touch each rounding mark, and
c. pass between the marks of a gate from the direction of the previous mark.
She may correct any errors to comply with this rule, provided she has not finished.
- takes a penalty under rule 44.2,
- corrects an error under rule 28.2 made at the line, or;
- continues to sail the course.