This past winter, a powerboat in the 100-ft range was enroute to Nassau.
The skipper entered the location of the Mackie Shoal light as a waypoint
in his GPS, knowing he had to make a course change at Mackie Shoal. He
set the boat's autopilot to steer to the waypoint.
The next morning, the powerboat motored into Georgetown harbor with the
Mackie Shoal light laying on his foredeck. His faithful autopilot had done
exactly what he had asked it to do, and steered that fine yacht right into
the tall light platform, causing it to collapse onto his boat.
So I'd say that the odds of hitting a small object in the middle of a large
area of water are directly proportional to how much one takes for granted.
-- Eric L. Pederson P-19 #970, Necessity Bloomington, MN