MOTOR ANODE 76 x 16 mm.

Function and technical context

Sacrificial anodes are cathodic protection elements installed directly on the outboard or inboard-outboard motor to prevent galvanic corrosion that progressively destroys the metal parts of the propulsion assembly. This 76 x 16 mm anode acts as an active electrode in the galvanic pair: being made of an alloy with a greater negative electrochemical potential than the aluminum or steel of the engine block, it preferentially oxidizes, absorbing the electrolytic attack that would otherwise degrade casings, axles, propellers and water covers. Its presence is especially critical in salt or brackish water environments, where the conductivity of the medium greatly accelerates electrolytic corrosion processes. An exhausted or missing anode leaves the engine completely unprotected, and can cause irreversible damage to high-cost components in a few weeks of navigation.

When to replace this part?

The clearest symptom that the anode has reached its useful life is the visible reduction in its mass: when it has lost approximately 50% of its volume, it must be replaced without delay, since its protection capacity is compromised. It is recommended to inspect the anodes at least once per nautical season or every time the engine comes out of the water for inspection, and replace them preventively at the beginning of each season if they show significant wear. Changing the anode before it is completely used up is the most economical measure to avoid major repairs to casings, shafts or propellers, the cost of which can multiply by a hundred the price of the anode itself.