ANODO DISCO POPA 140X30mm (ZN)

Function and technical context

The transom disc anode is a cathodic protection component designed to be mounted directly on the vessel's plate or transom, acting as a sacrificial anode that attracts electrolytic and galvanic corrosion before it affects the higher value structural metal parts. Made of zinc (ZN) with dimensions of 140x30 mm, this disc is placed between seawater or brackish water and the noble metals of the transmission, propeller, shaft and stern hardware. Its function is to be consumed in a progressive and controlled manner, preserving the integrity of the stainless steel, aluminum and bronze components of the propellant assembly. Without adequate cathodic protection, galvanic corrosion can silently degrade tailshaft, bearings, propeller and hull metal surfaces in a matter of months, especially in saltwater or eddy current environments.

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, since below that threshold they no longer offer effective protection. Unequivocal signs that the anode is exhausted are its appearance that is whitish, porous or directly reduced to a minimal fragment; If in parallel pitting or discoloration is observed on the shaft or propeller, the anode has not been changed for too long. Replacing the stern disc anode preventively at each annual grounding is the most economical maintenance measure to avoid major repairs to the axle or transmission, the cost of which can be several times higher.