COLLARIN EJE 3" (AL)

Function and technical context

The 3-inch aluminum shaft collar is a component of the shaft line drive system on boats with fixed shaft propulsion. Its main function is to hold and position the tail shaft in its correct place, avoiding unwanted axial displacements that would compromise the alignment between the engine and propeller. By working directly on the propulsion shaft, it acts as a structural retention element that maintains the integrity of the entire transmission assembly. A collar that is worn or has excessive play causes abnormal vibrations in the hull, loss of propulsive efficiency and can progressively damage the tight seal of the stuffing box or horn, with the consequent risk of water entering the bilge.

When to replace this part?

The most common symptoms that indicate that the shaft collar needs replacement are unusual vibrations felt in the frame or floor of the boat at cruising speed, noticeable play when manually moving the propulsion shaft axially, or visible scuff marks on the surface of the shaft. It is recommended to inspect the collar during each seasonal maintenance, checking the tightening of the fixing screw and the surface condition of the aluminum, especially in environments with high salinity where galvanic corrosion can accelerate deterioration. Replacing it preventively when signs of looseness or corrosion are detected prevents more serious damage to the shaft line that could leave the boat inoperative during navigation.

Compatibility