ANODE CAP

Function and technical context

Sacrificial anodes are cathodic protection elements designed to protect the submerged metal parts of the vessel against galvanic corrosion. This anode acts as a sacrificial metal, oxidizing in a controlled manner in place of the most valuable structural or mechanical components, such as propellers, shafts, keels or underbody of the outboard or inboard-sterndrive engine. Its correct operation depends on the navigation environment: salt, brackish or fresh water determines the most suitable alloy (zinc, aluminum or magnesium). Without effective cathodic protection, galvanic corrosion can silently attack metal parts in the drivetrain and engine casing, causing structural damage that is difficult and expensive to repair.

When to replace this part?

The clearest sign that an anode needs to be replaced is when it has lost between 50% and 75% of its mass, at which point its protection capacity drops significantly. It is recommended to check the condition of all the anodes at each mooring or at least once per navigation season, since their rate of wear varies depending on the hours of use, the type of water and the presence of parasitic electrical currents in the mooring. Replacing the anode preventively at the beginning of each season is the most recommended practice by naval mechanics, since its cost is minimal compared to repairing a corroded propeller or a shaft damaged by galvanic pitting.