ANODE SHAFT 45mm

Function and technical context

Shaft anodes are cathodic protection elements designed to be mounted directly on the tail shaft of the vessel, acting as an electrochemical sacrifice against galvanic corrosion that occurs when different metals coexist in a saline or brackish environment. The propulsion shaft is one of the most exposed parts of the hull: in permanent contact with water and subjected to galvanic currents generated by the propeller, rudder and hull, without adequate protection it can suffer severe corrosion that compromises the structural integrity of the entire transmission system. This 45 mm diameter anode (ref. CMX-45A) is installed hugging the shaft using two screwed half-clamps, guaranteeing continuous electrical contact and a correctly sized sacrificial surface for shafts of that size. Its function is to attract the electrochemical attack towards itself, preserving the shaft, horn, stuffing box and propeller from premature oxidation.

When to replace this part?

The clearest sign that a shaft anode needs to be replaced is visible mass loss: when the anode has consumed approximately half its volume, it has reached the limit of its useful life and must be replaced before it no longer provides effective protection. In practice, the shaft anodes are checked at each beaching and renewed at least once per nautical season, although in areas with high electrochemical activity or highly conductive waters it may be necessary to change them more frequently. A depleted or poorly secured anode that loses electrical contact with the shaft can lead to accelerated corrosion of the stainless steel or bronze shaft, resulting in marks, pitting and vibrations in the shaft line that ultimately require costly repair; Replacing it preventively at each seasonal tune-up is the most economical measure to protect the entire transmission.