What can cause galvanic corrosion on boats while connected to shore power?

Galvanic corrosion occurs when two dissimilar metals are electrically connected and submerged in a conductive solution, such as seawater. In the context of boats connected to shore power, metal parts that are in contact with water can indeed experience galvanic corrosion. This happens because the electrical current flowing through the water can facilitate corrosion, particularly if those metal parts are made of materials such as aluminum, bronze, or other metals that may be more susceptible to galvanic action.

When a boat is connected to shore power, it may become part of a larger electrical circuit that includes other vessels or metal components in the water. If those connected metals differ in potential, the more anodic (less noble) metal will corrode faster than it would if it were isolated. This is especially relevant when considering underwater metal components like the propeller, hull fittings, or even sacrificial anodes that are designed to prevent corrosion.

Materials like plastics, woods, and rubber do not conduct electricity and thus do not play a role in the galvanic corrosion process. They are not involved in the electrochemical reactions responsible for galvanic corrosion.