There is one phenomenon that beats even salt water when comes to corroding metal below the waterline – electrolysis. This occurs when stray electrical current “leaks” underwater and there are two dissimilar metals present. The current often emanates from a faulty shore power connection somewhere in the marina, but the results can be devastating, rapidly eating away metal fittings and propellers of boats as they sit tied up in their slips.
If electrolysis is an issue in your marina, contact your dock master so that the source of the stray current can be found as soon as possible. In addition, your boat may need special bonding wires, sacrificial zinc anodes or galvanic isolators to prevent damage from electrolysis in the future. Your boat yard can help guide you on what you need to avoid damage from electrolysis.