If you’ve ever looked at the underwater portion of your boat, you’ve likely noticed blocks of metal bolted to the outdrive, hull, or shaft. These aren't just extra hardware—they are your boat's frontline defense against a silent, expensive enemy: galvanic corrosion.

Choosing the wrongboat anodescan lead to thousands of dollars in ruined props, pitted hulls, and destroyed lower units. Let’s break down exactly how to choose between zinc, aluminum, and magnesium for your specific waters.