Mercury - Quicksilver 809666A03 Aluminum Prop Nut Anode MerCruiser Bravo Three Drives Corrosion Protection 809666A03. Overview. Corrosion doesn't make noise, but over time it can do real damage below the surface. The Quicksilver 809666A03 Aluminum Prop Nut Anode is built to stop that silent wear before it starts. Designed for MerCruiser Bravo Three drives (serial No. 0M179451 and below), this anode protects your propeller shaft and gearcase from galvanic corrosion - the kind that slowly eats awa