ANODO LAPIZ ONAN Ø11 31mm (ZN)

Function and technical context

This zinc pencil anode with a diameter of Ø11 mm and a length of 31 mm is designed to protect the metal components of the Onan marine generator against galvanic corrosion caused by the action of salt, brackish or fresh water. It acts as an electrochemical sacrifice: by preferentially oxidizing, it preserves the most valuable parts such as heat exchangers, engine blocks and generator cooling circuits. Without active cathodic protection, the noble metals of the generator set – brass, bronze or aluminum – would be exposed to electrolytic corrosion, which can lead to perforations, cooling circuit blockages and costly breakdowns. The reference REC9509 corresponds to a small diameter threaded pencil format, common in the insertion points of the seawater cooling blocks of the Onan generators installed on board.

When to replace this anode?

The clearest sign that the pencil anode needs to be replaced is that it has lost more than 50% of its mass or has an irregular, porous and deep grayish-white surface, a sign that the zinc has been consumed and no longer offers sufficient protection. On boats sailing in salt water or with high conductivity, it is recommended to inspect the pencil anodes at least once a season and replace them systematically at each annual beaching, without waiting for them to be completely used up. Changing the anode preventively is a low-cost intervention that prevents irreversible damage to the generator's cooling circuit, the repair of which can mean prolonged shutdowns and unforeseen economic events at the peak of the boat's use.