ANODE SHAFT 6

Function and technical context

The shaft anode is a sacrificial element made of active metal alloy that is installed directly on the boat's tail shaft to protect it against galvanic corrosion. It acts within the cathodic protection system, absorbing the electrolytic currents generated by the potential difference between different metals submerged in salt or brackish water. Without this component, the drive shaft, horn, stuffing box and other metal parts of the drive train are exposed to accelerated corrosion that can compromise the structural integrity of the assembly. Proper installation ensures that the anode material oxidizes preferentially rather than the more expensive elements of the transmission system.

When to replace this part?

Shaft anodes should be inspected at least once a season and replaced when they have lost between 30% and 50% of their mass, since below that volume they no longer offer effective protection. The most obvious symptoms of a depleted anode are pitting or visible surface corrosion on the drive shaft, horn or rudder eye, as well as discoloration in submerged metal areas. It is recommended to replace the anode preventively at each annual grounding to avoid severe damage to the shaft and associated components, the repair of which involves a much higher cost than the anode itself.