COLLARIN EJE CORTO 25 mm. (ZN)

Function and technical context

The 25 mm short shaft collar made of zinc (ZN) is a galvanic protection component that is installed directly on the tail shaft of the boat, in the transmission area between the engine and the propeller. Its main mission is to act as a sacrificial anode, absorbing the electrolytic corrosion generated by the galvanic currents present in salt or brackish water, thus protecting the propulsion shaft, propeller and other metallic elements of the drive train. Without this element in correct condition, the shaft is exposed to a progressive electrochemical attack that can compromise its structural integrity, cause play in the line bearings and lead to high-cost repairs or even the loss of the propeller during navigation.

When to replace this part?

The main symptom of exhaustion of a zinc collar is the visible loss of mass: when the anode has consumed more than 50% of its volume, it must be replaced immediately, as it no longer offers effective protection. Checking the shaft collars is part of the annual or seasonal beaching maintenance, and it is advisable to also inspect them mid-season in areas with high water conductivity. Replacing the collar preventively, before it is completely used up, is the most economical measure to avoid serious damage to the shaft and propeller that would require an unscheduled grounding repair.

Compatibility