COLLARIN EJE STD Ø 76,2 mm - 3' STD (ZN)

Function and technical context

The shaft collar is an axial fastening and positioning element located in the boat's transmission line, specifically in the tail shaft or propulsion shaft. Its main function is to keep the propulsion shaft correctly aligned and avoid unwanted longitudinal displacements that could compromise the operation of the drive assembly. Made of zinc (ZN), this collar simultaneously acts as a galvanic sacrificial element, protecting the stainless steel shaft and adjacent metal components against electrolytic corrosion produced by continued immersion in salt or brackish water. A worn, corroded or poorly secured collar can cause abnormal vibrations in the shaft, loss of propeller alignment and accelerated deterioration of the tail bearings and stuffing box, compromising the integrity of the entire propulsion line. This model corresponds to the standard diameter of 76.2 mm (3 inches), being compatible with installations that use that axle gauge.

When to replace this part?

The most common symptoms that indicate the need to replace the shaft collar are: noticeable vibrations or rattles in the propulsion line during navigation, visible play in the shaft when inspected with the boat dry, or severe corrosion and loss of mass of the zinc collar due to exhaustion of its galvanic sacrificial capacity. As it is a sacrificial anode integrated into the structural function of the collar, it is recommended to inspect it at each seasonal stranding and replace it when the loss of material exceeds 50% of its volume, or at least once a year in vessels that navigate in salt waters. Replacing the shaft collar preventatively ensures continued shaft protection and prevents costly drive system repairs that could render the boat inoperable.

Compatibility table