ALUMINUM STERN ANODE 159 x70

Function and technical context

The aluminum stern anode acts as a cathodic protection element in the stern area of ​​the boat, sacrificing itself electrochemically to protect the noblest metallic parts of the propulsion assembly—propeller, shaft, support and transmission box—against galvanic corrosion produced by prolonged contact with salt, brackish or fresh water. Being made of aluminum, this anode is especially suitable for use in salty and intermediate waters, where its sacrificial potential is optimal compared to the aluminum of the outboard engine or propulsion system components. Without effective cathodic protection, the metal components of the stern assembly suffer accelerated galvanic attack that can render the shaft useless, damage the propeller or compromise the structural integrity of the transmission, leading to serious and costly breakdowns.

When to replace this anode?

The clearest sign that the anode needs to be replaced is the visible reduction in its mass: when it has consumed between 50% and 75% of its initial volume, the protection capacity decreases significantly and adjacent metal components are exposed to galvanic corrosion. It is recommended to inspect the anodes at least once a season – ideally at each beaching or annual inspection – and replace them preventively before they reach that wear threshold, regardless of the time elapsed. Don't wait to see pitting on the shaft or propeller: replacing the anode in time is the most economical maintenance intervention to avoid major repairs to the propulsion systems.