Galvanic Corrosion is the result of tiny electrical currents that leech the metal from your boat’s hull and underwater metalwork. It’s not the same as Microbial corrosion, (which is easily controlled by effective hull coatings). Galvanic corrosion occurs when a boat is connected to an electric hook up.
How To Check:
Check around the waterline of your boat. If there’s pitting similar to that in the images, there’s a good chance that it’s being caused by Galvanic currents.
In many cases, you’ll see that the pitting is silver in colour. The silver is from your anodes. It’s zinc or aluminium that has plated the pits in the hull. It follows then, that your anodes are likely to be badly depleted too. But even if the pits aren’t silver in colour, you should still suspect Galvanic corrosion – especially if your anodes are BADLY corroded.