ANODE CASTOLDI

Function and technical context

The sacrificial anode is the key component of the cathodic protection system in Castoldi outboard engines, inboard engines and marine propulsion equipment. Its function is to oxidize in a controlled manner to protect the noble metal parts of the engine—aluminum, stainless steel and bronze—against galvanic corrosion produced by the action of salt, brackish or mineral-containing water. Acting as a sacrificial electrode, the anode absorbs electrochemical attack that would otherwise degrade structural components of the propulsion system. Its correct installation and periodic replacement is essential to preserve the integrity of the drive unit and avoid irreversible damage to high-cost parts.

When to replace this part?

Sacrificial anodes should be inspected at least once a season, coinciding with docking or annual maintenance of the vessel. The unequivocal sign that the anode requires replacement is the loss of more than 50% of its mass: when the material has been consumed in excess, the cathodic protection is no longer effective and corrosion pits begin to appear on the metal surfaces of the engine or propeller. It is recommended to replace the anode preventively at each seasonal tune-up - without waiting for its complete exhaustion - since the cost of replacement is minimal compared to repairing a shaft, pump body or transmission casing damaged by electrolytic corrosion.