ZINC BAR 45x400

Function and technical context

The 45x400 mm zinc bar is a sacrificial anode designed to protect the propulsion shaft of vessels against galvanic corrosion. It acts as a cathodic protection element: being a more electronegative metal than the steel or bronze of the shaft, it preferentially corrodes, preserving the integrity of the propellant component. This type of protection is especially critical in salt and brackish water environments, where electrolytic corrosion can degrade the shaft in a few seasons if there is no adequate active protection. Without an anode in good condition, the shaft is exposed to pitting, loss of section and, in advanced cases, breaks that compromise navigation.

When to replace this part?

Zinc anodes should be inspected at least once a season, coinciding with the annual docking of the vessel. The clearest sign that the anode has exhausted its useful life is a reduction in mass of more than 50%, at which point it significantly loses protective effectiveness. It should also be replaced if it shows cracks, fragmentation or has become detached from the shaft. A common professional tip in the shipyard is to replace it preventively at each grounding, since the cost of the anode is minimal compared to repairing or replacing the shaft due to advanced corrosion.

Compatibility