ANODO HELICE TWIN DISC-BCS Ø50 (AL)

Function and technical context

This propeller anode made of aluminum is designed specifically for Twin Disc-BCS propulsion systems with a 50 mm diameter shaft, and acts as sacrificial cathodic protection of the propeller and propeller shaft assembly. Its mission is to concentrate the galvanic corrosion process on itself, thus preserving the most valuable metal components—propeller hub, shaft, horn and other elements of the transmission line—against the electrochemical attack of sea or brackish water. The aluminum alloy used in its manufacture makes it the ideal option for navigation in marine and brackish waters of medium-high salinity, where it offers a higher cathodic protection efficiency than zinc anodes in that conductivity range. Without anodic protection in good condition, galvanic corrosion can progressively degrade the propeller and shaft leading to structural failure, abnormal vibrations or loss of propulsive performance.

When to replace this part?

Sacrificial anodes should be inspected at least at the beginning and end of each sailing season, and replaced when they have lost approximately 50% of their mass, present a very irregular surface, or show severe erosion that compromises attachment to the propeller hub. An excessively consumed anode leaves the shaft and propeller unprotected, a situation that can manifest itself as visible pitting in the base metal, greenish-whitish discoloration around the hub or accelerated corrosion in the horn. Replacing the anode preventively at the beginning of the season is the practice recommended by any professional nautical workshop: the cost of a new anode is minimal compared to repairing or replacing a propeller or shaft damaged by galvanic corrosion.