ANODE SHAFT 80mm.

Function and technical context

Shaft anodes are the key component of the cathodic protection system on fixed shaft propulsion vessels. Their mission is to act as a sacrificial metal, attracting galvanic corrosion to themselves to preserve the tailshaft, propeller, and other submerged metal elements of the vessel. Being made of a more electrochemically active alloy than stainless steel or naval bronze, the anode corrodes in a controlled manner instead of the structural components of the transmission system. Without effective cathodic protection, the tail shaft is exposed to electrolytic corrosion, which can cause pitting, structural weakening and, in advanced cases, vibrations, loss of packing gland seals and irreversible damage to bearings and coils.

When to replace this part?

The most obvious symptom that the shaft anode has exhausted its useful life is the visible reduction in its mass: when it has lost approximately 50% of its volume, it must be replaced without delay so that the cathodic protection remains effective. It is recommended to inspect and replace the shaft anodes at least once a season, coinciding with the annual beaching of the boat, since in salty or brackish waters wear may be faster than expected. Replacing the anode preventively is the most economical maintenance measure available: the cost of an anode is minimal compared to repairing or replacing a tail shaft damaged by galvanic corrosion.