ZF BAR ANODE

Function and technical context

Sacrificial rod anodes are fundamental elements in the cathodic protection system of vessels with transmissions and tail shafts. This zinc anode acts as a sacrificial electrode: being a less noble metal than steel, aluminum or bronze of the structural and transmission parts, it preferentially corrodes, protecting the vital components of the propulsion train. Its correct installation in the ZF transmission ensures that galvanic corrosion – accelerated by the marine environment, especially in salt or brackish waters – does not compromise gears, housings or axles, the repair or replacement of which would be enormously expensive.

When to replace this anode?

The clearest indicator that a sacrificial anode needs to be replaced is mass loss: when the anode has consumed approximately 50% of its volume, it has reached the limit of its useful life and no longer offers effective protection. A warning sign is finding corrosion pits on adjacent metal parts of the transmission, indicating that the anode has been depleted without being renewed in time. It is recommended to inspect and replace the bar anodes at least once per nautical season—or more frequently if the boat remains moored in areas of high electrical conductivity of the water—; Replacing them preventively at each docking avoids severe damage to the ZF transmission components and saves costly out-of-port interventions.