COLLARIN EJE 40mm. STD (ZN)

Function and technical context

The 40 mm shaft collar in standard finish with zinc (ZN) protection is the component responsible for fixing and axially positioning the tail shaft in the transmission of a boat, avoiding unwanted longitudinal displacements that could compromise the alignment between the engine and propeller. It works within the transmission and propulsion system, acting as a mechanical retention element that maintains the shaft in its working position under the thrust loads generated during navigation. The zinc integrated into its construction fulfills a protective galvanic function, sacrificing itself against electrolytic corrosion that affects submerged metal components, thus prolonging the useful life of both the collar and the shaft itself. If this component fails or loses its structural integrity, the shaft can suffer axial movements that cause vibrations, loss of propulsive efficiency, accelerated bearing wear, and in extreme cases, severe damage to the stuffing box or horn.

When to replace this part?

The most common symptoms that indicate the need to replace the shaft collar include abnormal vibrations transmitted to the hull during navigation, noticeable play in the shaft when manually pushing or pulling it with the engine stopped, and visible wear or advanced corrosion on the collar itself or its zinc anode. Since the protective zinc is consumed progressively, it is recommended to inspect the condition of the collar at each beaching or seasonal maintenance, replacing it when the anode has lost more than half of its mass. Acting preventatively by replacing the collar before the zinc is completely depleted prevents corrosion from reaching the metal shaft, which would result in a considerably more expensive repair.

Compatibility