ANODE SHAFT 2-3/4

Function and technical context

Shaft anodes are essential elements within a vessel's cathodic protection system: their mission is to electrochemically sacrifice themselves to protect the propulsion shaft—and adjacent metal components such as the propeller, stuffing box, and keel bearings—against galvanic corrosion produced by prolonged immersion in salt or brackish water. The propulsion shaft, being made of stainless steel or bronze and in permanent contact with water and other metals of different electrochemical potential, is especially vulnerable to accelerated corrosion if it does not have adequate anodic protection. The CMC-12A anode is installed directly on the shaft, acting as a sacrificial metal that concentrates the corrosive attack on itself and preserves the structural and functional integrity of the shaft. Without this type of protection, degradation of the axle can compromise the tightness of the system, generate abnormal vibrations in the propulsion line and even lead to serious breakdowns of the drive assembly.

When to replace this part?

The clearest sign that a shaft anode has reached its useful life is the visible reduction in its mass: when the anode has lost approximately half its volume, it should be replaced immediately, regardless of the time elapsed. As a general rule, it is recommended to inspect and replace the shaft anodes at least once per nautical season - coinciding with the annual beaching - or more frequently if the boat remains in areas with high conductivity water or contaminated waters that accelerate the galvanic corrosion process. Delaying replacement of the anode exposes the shaft and propeller to severe corrosion that can require costly rectifications or even a complete shaft replacement in the middle of the season.

Compatibility table