ANODE SHAFT 1-3/4

Function and technical context

The shaft anode is a sacrificial element that is part of the boat's cathodic protection system, acting directly on the tail shaft to prevent galvanic corrosion caused by contact between dissimilar metals submerged in salt or brackish water. Installed on the propulsion shaft, it corrodes in a controlled manner instead of the steel or bronze of the shaft itself, the buttress seals and the transmission elements. Without adequate cathodic protection, corrosion can attack the shaft until its structural integrity is compromised, causing vibrations, damaging sealing seals and generating costly repairs in the dock. The CMC-8 model is designed for 1-3/4 inch (44.45 mm) diameter shafts, ensuring a secure fit and effective electrical contact between the anode and shaft.

When to replace this part?

The main indicator that the shaft anode needs to be replaced is visible mass loss: when the anode has consumed approximately 50% of its volume, it has ceased to offer sufficient protection and must be replaced immediately, regardless of the time elapsed. Under normal use conditions, it is recommended to inspect the anodes at each seasonal docking and replace them at least once a year, or sooner if the boat usually navigates in waters with high conductivity or is moored in areas with eddy currents. Delaying replacement is one of the most common mistakes in nautical maintenance: a corroded shaft can mean a repair cost much higher than the cost of a simple sacrificial anode.

Compatibility table