COLLARIN EJE 34mm. STD (ZN)

Function and technical context

The 34 mm shaft collar in standard version with zinc protection is a critical component of the drive system in shaft-driven boats. Its main function is to axially fix the tail shaft in its correct position, avoiding unwanted longitudinal displacements that would compromise the alignment between the engine and propeller. Being manufactured with zinc protection, it simultaneously acts as a galvanic sacrificial element, protecting the stainless steel or bronze shaft against electrolytic corrosion caused by the action of salt or brackish water. A worn, corroded or zinc-depleted collar can lead to abnormal vibrations, progressive shaft misalignment and accelerated deterioration of the bollard or stuffing box packing.

When to replace this part?

The most common symptoms of a shaft collar in poor condition are unusual vibrations perceived in the hull during navigation, axial play detectable when manually moving the shaft and the presence of visible corrosion or practically consumed zinc. As it is a component with a built-in anode function, it is recommended to inspect it at the beginning of each nautical season and replace it when the zinc has lost more than 50% of its mass, regardless of the mechanical state of the collar. Preventive replacement each season ensures continued protection of the shaft and prevents costly repairs due to galvanic corrosion or damage to the horn while boating.

Compatibility table