ANODE SHAFT 120MM

Function and technical context

The shaft anode is a cathodic protection element designed to be installed directly on the propeller shaft, acting as an electrochemical sacrifice against galvanic corrosion that occurs in the marine environment. Being manufactured from a zinc or aluminum alloy with a higher anodic potential than the steel or bronze shaft, it attracts corrosion and degrades in place, preserving the integrity of the drive shaft, line bearings, horn and other submerged metal transmission components. Without adequate cathodic protection, the shaft can suffer pitting and material loss that compromises alignment, generates vibrations and can lead to breakage or the need to replace high-cost elements. This 120 mm anode is sized for the shafts of medium-large boats and is fixed using clamps, guaranteeing continuous electrical contact with the shaft throughout the sailing season.

When to replace this part?

Shaft anodes should be inspected at least once a season, usually at the annual stranding, and replaced when they have lost approximately 50% of their mass, since below that level the cathodic protection is insufficient. The most obvious sign that the anode has exhausted its useful life is the appearance of pitting, surface oxidation or discoloration on the shaft itself or on adjacent metal parts of the transmission line. Replacing the anode preventively at each grounding is the most economical measure to avoid corrosion of the shaft and the grinding or replacement costs that a damaged shaft entails.