ZINC REPLACEMENT

Placing metals in water may result in two occurrences which boat operators should be aware of. These are electrolysis and galvanic corrosion. Of the two, electrolysis is the more common concern.

Electrolysis happens when different metals exchange electrons while in an electrolytic solution, such as saltwater. The exchange occurs when electrical currents stray or deviate from their normal paths.

Electrolysis is harmful to a boat’s underwater equipment, as it may cause the metal parts to weaken and corrode.

The other phenomenon which boat owners have to deal with is galvanic corrosion, which is the formation of a natural battery occurring when two dissimilar metals make contact in an electrolytic solution.

Rather than the exchange of ions that happens in electrolysis, in galvanic corrosion one metal will transfer ions to the other, weakening the metals. The result will show up as uneven surfaces, cavities and pitting in parts.

Metal parts such as propellers, shafts, nuts and rudders are prone to corrosion by these two processes whenever they are placed in saltwater. To protect them, zincs, or ‘sacrificial anodes’ are installed on the boat. As a less noble metal than the metals used on boat components, the zincs will deplete more quickly, giving up, or ‘sacrificing’ their ions while preserving those of the boat’s metal parts.

Over time, the boat’s zincs will deplete themselves and have to be replaced with new zincs to protect the vessel’s parts from deterioration by electrolysis and galvanic corrosion. Catching electrolysis early and replacing worn out zincs can prevent damage to crucial running gear.

Barnacles Bills offers zinc inspections and replacement to ensure the long life of your boat’s underwater equipment.