ANODO HELICE RIVA Ø155 (ZN)

Function and technical context

The Ø155 mm Riva propeller anode is a cathodic protection element designed specifically for mounting on the hub or propeller shaft of boats with outboard or inboard engines. Its function is to act as a sacrificial metal, absorbing galvanic corrosion that would otherwise attack the propeller, shaft and other submerged metal components. Made of zinc (ZN), it is the recommended alloy for salty and brackish waters, where electrolytic activity is more aggressive. Without effective cathodic protection, the propeller and shaft can suffer from pitting, structural weakening and material loss that compromises both propulsion performance and boat safety.

When to replace this part?

The most obvious signs that the propeller anode needs replacement are a visible reduction in mass – when it has consumed between 50% and 70% of its volume – or when it appears completely corroded and no longer covers the exposed surface of the propeller hub. It is recommended to inspect and replace the zinc anode at least once per nautical season, or sooner if the boat remains anchored in waters with high electrical conductivity or in port areas with high galvanic currents. Changing the anode preventively at the beginning of each season is the most common practice among professional naval mechanics and prevents corrosion from reaching much higher cost parts such as the shaft or propeller.

Compatibility table