ANODE SHAFT 35 mm.

Function and technical context

Shaft anodes are fundamental elements in the cathodic protection system of shaft-powered vessels. Its function is to act as a sacrificial metal: being more electronegative than the stainless steel or bronze of the drive shaft, the anode preferentially corrodes, protecting the shaft from galvanic corrosion produced by the action of salt or brackish water. This zinc anode with an internal diameter of 35 mm is designed to be installed directly on the tail shaft, being fixed using tightening screws that guarantee permanent electrical contact. Without adequate cathodic protection, the propeller shaft can suffer pitting, accelerated erosion and even structural failure, with the consequent risk of loss of propulsion during navigation.

When to replace this part?

The main indicator that a shaft anode needs to be replaced is mass loss: when the anode has consumed approximately 50% of its volume, it has reached the limit of its useful life and its protection capacity is compromised. As a general rule in preventive maintenance sailing, it is recommended to inspect the shaft anodes at each seasonal stranding and replace them whenever they show wear by more than half, regardless of the time elapsed, since the aggressiveness of the marine environment varies depending on the navigation area, water temperature and type of electrical installation on board. Replacing the shaft anode preventively each season is a minimal investment that prevents premature deterioration of the drive shaft, a significantly higher cost and repair component.