COLLARIN EJE 1 1/4" STD (ZN)

Function and technical context

The 1 1/4" STD shaft collar with zinc protection is the fastening and axial positioning element of the tail shaft in boat propulsion installations. It works in the transmission system, fixing the propeller shaft in its correct longitudinal position and preventing unwanted movements that would compromise the alignment with the stern tube bearing and stopper. By incorporating zinc (Zn) material, it simultaneously acts as an integrated sacrificial anode, offering cathodic protection to the steel shaft stainless or bronze in marine environments with risk of galvanic corrosion. If this component wears or loses its active zinc, the shaft is exposed to electrolytic corrosion and axial movement may occur that generates vibrations, damage to the horn and accelerated deterioration of the stuffing box.

When to replace this part?

The most common symptoms that indicate that the shaft collar needs to be replaced are: unusual vibration in the drive shaft, noticeable axial play when moving the shaft manually, visible corrosion on the surface of the zinc, or a reduction in mass of more than 50%. As it is a component with a sacrificial anode function, it is recommended to inspect the collar at least once a season and replace it when the zinc is consumed or cracked, regardless of the number of hours of navigation. A key pro tip: changing the collar preventatively at each grounding avoids severe corrosion problems on the shaft and saves costly shipyard repairs.

Compatibility table