SPARE ZINC 19 x 19mm.

Function and technical context

This 19 x 19 mm replacement zinc acts as a sacrificial anode, protecting the metal structure of the boat against galvanic corrosion that occurs when different metals come into contact in an electrolytic medium such as salt or brackish water. Being a more electronegative metal than the steel, aluminum or bronze present in propellers, shafts, keels and stern accessories, zinc preferentially corrodes in its place, sacrificing itself to preserve the most expensive and critical components of the propulsion and steering system. Its correct installation is essential in any boat that remains in the water continuously, since galvanic corrosion can irreversibly damage high-cost parts in a matter of weeks if the anode is exhausted or absent.

When to replace this part?

Zinc anodes should be inspected at least at the beginning and end of each nautical season, and replaced when they have lost approximately 50% of their mass, present pronounced surface cracks, or show a sandy, disintegrated texture that indicates depletion of the active material. An excessively consumed or absent anode is easily detected visually during grounding, although the most worrying symptom is finding pitting corrosion on the shaft, propeller or stern fittings, a sign that the cathodic protection has failed. Preventively replacing zinc at each annual docking is the most economical measure to avoid costly repairs to propulsion components, being especially important in mooring areas with high galvanic current or water with high conductivity.

Compatibility table