Out of sight, out of mind might best describe a very serious hidden danger in boating. Because of the speed and torque, this hidden danger has the potential to kill, mangle or permanently disfigure an unsuspecting person in the water. That hidden danger is the boat engine propeller ("propeller strike").
Propeller related accidents represent 4 percent of all boating fatalities, with a growing number of injuries.
Operating below the water line, the propeller is not readily visible to the operator, passengers, swimmers, skiers, etc. Common propeller strike events include “crew-overboard” and/or “circle of death” incidents. If you have a “crew overboard” event, you should immediately turn toward the person in the water in order to push the stern in the opposite direction. Simultaneously, you should shift to neutral to stop the propeller from spinning.
A “circle of death” event occurs when the operator goes overboard and/or loses control of the steering. Whether you have an outboard or inboard engine, more likely than not your propeller is designed to spin in a clockwise manner. This built in prop pitch introduces “prop walk”, which, depending on the amount of throttle still applied when steering is lost will cause the boat to circle. This circling action has the potential of creating a scenario where the operator, now in the water, is actually run over by the boat and potentially hit by the propeller.