Was it impossible to avoid contact?

The Case Book for 2025-2028 (click here) complements The Racing Rules of Sailing (RRS) and provides details on the application of the rules. Here’s Case 87:

A right-of-way boat need not act to avoid contact until it is clear that the other boat is not keeping clear.

Facts
The angle of the starting line made it only just possible for a close-hauled boat on starboard tack to cross the line, and most boats approached on port tack. However, S approached on starboard tack from the right-hand end, continually hailing ‘Starboard’ to port-tack boats as they approached.

P1 and P2 bore off below S. P3, however, made no attempt to avoid S and struck her amidships at right angles, causing considerable damage. The protest committee disqualified both boats, P3 under rule 10 and S under Rule 14 (Avoiding Contact). S appealed. – Full report