ANODE SHAFT 2

Function and technical context

The shaft anode is a cathodic protection element that is installed directly on the boat's transmission shaft, acting as a sacrificial metal against galvanic corrosion. Its function is to attract electrochemical wear that would otherwise affect the shaft, propeller and other higher cost submerged metal components. It works in the propulsion system, in the submerged area of ​​the shaft-horn-propeller assembly, being especially critical in salt and brackish water environments where galvanic corrosion is more aggressive. If the anode is completely consumed without being replaced in time, the steel or bronze shaft is exposed to the electrolytic action of water, which can cause pitting, structural weakening and irreversible damage to the shaft line.

When to replace this part?

The clearest sign that the shaft anode needs to be replaced is a reduction in mass by 50% or more from the initial size; When the anode appears irregular, very reduced or with completely consumed areas, it has stopped protecting effectively. Common practice among naval mechanics is to check and replace shaft anodes at each seasonal beaching, generally once a year, although in areas with high water conductivity it may be necessary to do so more frequently. Replacing the CMC-9 anode preventively before launching is the most economical measure to avoid the costly repair or replacement of a shaft damaged by electrolysis.