Re: Zinc Anodes
For anyone interested, zinc anodes provide something called cathodic protection to the submerged drive parts.
It forms a battery with the zinc being the negative electrode, the aluminum drive is the positive, water is the electrolyte.
Different conductive materials in an electrolyte all have their own natural voltage, aluminum being more positive than zinc.
The resultant current from anode to cathode forms oxygen on the zinc, which slowly erodes metal from it (hence the name "sacrificial anode"), and forms a microscopic film of hydrogen on any exposed bit of aluminum of the drive. The hydrogen film prevents oxygen in the water from combining with the aluminum, thereby limiting corrosion.
A MerCathode system operates on the same principal.
Now for the kicker;
A polished stainless prop looks really nice, but wreaks havoc on aluminum drive parts. That's because stainless has chromium, copper, steel, nickel and more in it, the combination of which is more positive than aluminum.
The solution? Clear or black powder coat your ss prop.
