How would you decide this?

Dave Perry’s 100 Best Racing Rules Quizzes highlights specific aspects of the racing rules in a fun format designed to help you become more familiar with The Racing Rules of Sailing. Here is one of the quizzes:

Quiz 40
Two 25-foot boats, SI and PO, are approaching a single leeward mark to be left to port. SI, on the inside, is on starboard tack and PO is on port tack. SI sails her VMG course and gybes onto port tack when approximately two lengths from the mark while PO is hailing, “You are taking too much room!” SI’s boom makes contact with PO’s port shroud causing no damage or injury. Both boats hail, “Protest!” and display their protest flags.

You are on the protest committee…how would you decide this? Answer below.

Quiz 40 Answer:
Penalize PO for breaking rule 18.2(a)(1), Giving Mark-Room. When SI reaches the zone, SI and PO are overlapped. Therefore, PO is required to give SI mark-room under rule 18.2(a)(1). However, SI is the right-of-way boat under rule 10, On Opposite Tacks, so she breaks no rule by not sailing within the mark-room to which she is entitled while on starboard tack.

Because SI is an inside, overlapped, right-of-way boat which needs to gybe in order to sail her proper course around the mark, rule 18.4, Gybing in the Zone, requires her to sail no farther from the mark than needed to sail her proper course. SI is within her proper course when she gybes at position 2 (see the definition Proper Course). There- fore, she complies with rule 18.4.

When SI gybes at position 2, she becomes a windward boat and she does not keep clear of PO, so she breaks rule 11, On the Same Tack, Overlapped. However, because her proper course is to sail close to the mark, mark-room includes room to sail to the mark, which she is doing (see the definition Mark- Room). Therefore, she is sailing within the mark-room to which she is entitled, and is exonerated (freed from penalty) by rule 43.1(b), Exoneration, for her breach of rule 11.”

And even if it was decided that either of the boats broke rule 14, Avoiding Contact, they are each exonerated for that breach by rule 43.1(c) because PO is the right-of-way boat and SI is sailing within the mark-room to which she is entitled, and the contact did not cause damage or injury.

Source: US Sailing