AIFO ANODE

Function and technical context

Sacrificial anodes are the fundamental component of the cathodic protection system in marine engines and propulsion units. Its mission is to protect the metal parts of the engine - such as the block, tail or propeller shaft - against galvanic corrosion caused by the electrolytic action of salt or brackish water. Being made of a metal with a higher anodic potential, the anode corrodes in a controlled manner instead of the structural parts of the engine, acting as a sacrificial shield. Without this active protection, galvanic degradation can compromise high-cost components such as the tail casing, propeller mounts or shaft surfaces in just a few seasons.

When to replace this part?

The clearest sign that the anode needs to be replaced is the visible reduction in its mass: when it has lost approximately 50% of its initial volume, the protective capacity is compromised and it must be replaced immediately. It is recommended to inspect the anodes at least once a season—or more frequently in areas of high salinity or with parasitic electrical currents in the mooring—and replace them preventively at the beginning of each nautical season even if they retain apparent mass. Delaying the change of a worn anode can lead to severe corrosion on structural parts of the engine whose repair or replacement involves a much higher cost than the anode itself.

Compatibility