Back in November 2011 we covered Mercury Marine’s Moving Propeller Alert. It displays LED lights to swimmers behind the vessel when the engine is running. Those same LED lights blink in a rotational pattern when the engine is on and the propeller is rotating. The propeller safety device was originally limited to boats with Mercury’s SmartCraft CANBUS network.

Mercury Marine MP Alert oval bezel

As to use on non-Mercury systems, as we understand it, a switch in the dash allow the operator to turn the system off and on when swimmers are in the water. The two page flyer does not specifically say the lights automatically rotate when the engine is running and shifted into gear on non-Mercury outboards. They may be asking the operator to switch it on at those times when swimmers are in the water.

The LED lights are automatically dimmed at night so they will not be confused with navigational lights.

Mercury issued a colorful 2 page pdf sheet describing the updated MP Alert propeller safety system.