ANODE SHAFT 22 mm.

Function and technical context

The shaft anode is a cathodic protection element designed to be mounted directly on the tail shaft of the vessel, acting as a sacrificial metal to preserve both the shaft and the propeller and other submerged metal components. Being made of zinc or an active alloy with a more negative electrochemical potential, it attracts galvanic and electrolytic corrosion that would otherwise attack the structural parts of the propulsion system. This anode is sized for 22mm diameter shafts, so its fit is precise and ensures optimal electrical contact with the shaft. Without adequate cathodic protection, the shaft can suffer from pitting, accelerated erosion, and loss of resistant section, which compromises the structural integrity of the driveline and can lead to costly shaft or horn repairs.

When to replace this part?

Shaft anodes should be inspected at least once a season, coinciding with the annual docking of the vessel; The practical rule established by professionals in the sector is to replace them when they have lost approximately half of their mass, without waiting for them to be completely consumed, since an exhausted anode leaves the shaft unprotected against galvanic corrosion. Obvious signs that the anode has reached its useful life are: completely corroded surface, visible reduction in volume, or presence of incipient pits on the stainless steel shaft itself. Preventive replacement in each nautical season is the practice recommended by naval maintenance workshops, since the cost of the anode is minimal compared to machining or replacing a shaft damaged by corrosion.