I crossed a starboard boat well clear, she bore away hard anyway and protested — who takes the penalty?

Nobody. Rule 10 makes port keep clear, and the definition of Keep Clear is met if the starboard boat could sail her course with no need to take avoiding action. Port was already past, so a turn she didn't need is not avoiding action and the protest is dismissed. But mind World Sailing Case 50: when starboard does change course and the protest committee has reasonable doubt that port would have crossed, port is disqualified. A close cross is a bet on what the jury will believe.

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Next on this shelf — The Upwind Beat