What is Galvanic Corrosion?
Galvanic corrosion (sometimes erroneously called electrolysis) can damage or destroy underwater metal parts of boats, dock hardware and other equipment. When two different metals are touching each other or are electrically connected by a conductor, and are immersed in an electrolyte (an electrically conductive fluid, like salt water) an electro-chemical reaction can occur. One of the metals (the “least noble” metal, called the anode) will corrode faster than it normally would, and the other (The “most noble” metal, or the cathode) will dissolve more slowly. The seawater Galvanic Sequence lists metals in order, based on their voltage potential and tendency to corrode. More active metals, the faster-dissolving anodes, are at the top of the series. Passive metals, the cathodes, are located at the bottom. Your boat might have a collection of submerged electrically connected metal parts immersed in salt water surrounding the boat, in bilgewater or the water in the engine cooling system. The
