The race committee told the skipper he had not finished. The boat recrossed the line without losing a place.
First of all, someone should smack the race committee for communicating that to the boat. It's not their place to tell someone if they finished correctly or not.
Secondly, if Boat B corrected her mistake (did a circle for hitting the mark, then finished correctly), then they should be scored in their finishing position.
Even if Boat B did not do her penalty turn, the only recourse of the Race Committee is to protest her since she "finished".
