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 42
Boats PA and PB, two port-tack boats, are approaching a leeward mark to be left to port. When approximately one length from the zone, PA hails, “No overlap…no Room!” PB responds, “We’re not there yet!” After both boats are in the zone, PB hails, “I got the overlap before you reached the zone… Room!” PA responds, “No, you didn’t…no Room!” PA did not give PB room to round the mark. PB protested PA.

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

Quiz 42 Answer:
Disallow PB’s protest. At position 1, before PA reached the zone, PA was clear ahead of PB. Inside the zone the boats were overlapped. PB claims to have created the overlap before PA reached the zone; PA claims that PB did not create the overlap before PA reached the zone. Rule 18.2(e), Giving Mark-Room, states: “If there is reasonable doubt that a boat obtained or broke an overlap in time, it shall be presumed that she did not.” There is “reasonable doubt” that PB obtained the overlap before PA reached the zone; therefore the protest committee must assume she did not obtain the overlap in time. Therefore, PA was not required to give PB mark-room under rule 18.2(a), Giving Mark-Room. (See US Sailing Appeal 92.)

Source: US Sailing