RECTANGULAR ANODE 70x50x15

Function and technical context

Rectangular sacrificial anodes are key elements in the cathodic protection system of boats and outboard or inboard motors. Its mission is to protect submerged metal parts—such as propellers, shafts, casings and engine underbody—against galvanic corrosion, a phenomenon that silently and irreversibly degrades metal when different metals coexist in contact with salt or brackish water. Being a more electrochemically active metal, the anode preferentially corrodes critical vessel components, acting as a consumable shield. Without adequate cathodic protection, corrosion advances on high-cost parts such as the drive shaft, submerged exhaust system or engine casing, causing serious breakdowns and high-cost repairs.

When to replace this part?

The clearest symptom that a sacrificial anode needs replacement is the visible reduction in its mass: when the anode has lost approximately half of its volume, it no longer offers sufficient protection and must be replaced immediately. It is recommended to inspect the anodes at least once a season - ideally at each beaching or annual inspection - and replace them whenever they show more than 50% wear, without waiting for them to disappear completely. Replacing the anode preventively at the beginning of each nautical season is the most economical practice to avoid corrosion damage to components that are difficult to access or have high repair costs.