If your not sure the overlap was broken, it wasn’t

RULE 

Part 2 - When Boats Meet

Section C - At Marks and Obstructions

Rule 18.2 (d) If there is reasonable doubt that a boat obtained or broke an overlap in time, it shall be presumed that she didn’t.

Buoy room rules do not apply at a starting mark surrounded by navigable water or at its anchor line from the time boats are approaching them to start until they have passed them... 

PURPOSE

Protect the rights of the entitled boat.