P changed course twice to avoid S.
16.1 "when a right-of-way boat changes course she shall give the other boat room to keep clear."
Sounds like S didn't give P room to keep clear.
Happens alot on the race course, if P pinched, even to the point of almost stopping, she may have cleared S and not lost much ground. They were on the same boats so P must have been aware that S may steer the course that they did. Risky move to bareaway across the bows of a spinnaker boat.
Darryn