Clipping the finishing mark
The situation
Squeezing across the line right beside the pin, an Opti's hull brushes the finishing mark as she crosses.
The question
Does touching a finishing mark matter when you're basically done?
The ruling
Yes — finishing marks are marks too. Touching one breaks rule 31, and she must take a One-Turn Penalty to clear it. And rule 44.2 has a special twist at the finish: a boat taking a penalty at or near the finishing line must sail completely to the course side of the line before finishing. So she does her turn, then re-crosses to finish properly. Brushing the mark and sailing on without the turn leaves her in breach of rule 31.
Finishing marks count — clip one and you owe a One-Turn Penalty, then re-cross to finish (rules 31, 44.2).
Opens the situation on the boat-length grid — scrub it and see exactly how the boats meet. Free, no account needed.
Rules cited
See the underlying rule: Rule 31 — Touching a Mark.