2 1/4 SHAFT COLLAR

Function and technical context

The shaft collar is a component of the transmission system responsible for axially fixing the propeller shaft and preventing its longitudinal displacement during the operation of the outboard or inboard engine. It works in the shaft exit area, in close collaboration with the stuffing box, thrust bearings and shaft seal assembly, forming part of the power transmission system to the propeller. Its correct fastening guarantees that the propeller maintains the intended working position, avoiding vibrations, looseness and premature wear in the adjacent elements. If the shaft collar is cracked, severely corroded, or loses its tightness, uncontrolled movement of the shaft may occur, compromising the seal, generating noise, and may lead to water entering the bilge or serious damage to the shaft horn.

When to replace this part?

The most common symptoms that indicate that the shaft collar needs replacement are: noticeable axial play in the propeller shaft when manually pushing and pulling it, abnormal vibration transmitted to the hull at certain revolutions, or visible wear in the form of grooves, galvanic corrosion or ovalization in the contact area. It is recommended to inspect the collar at each docking or seasonal maintenance, since continuous exposure to salt water and the tensile and compressive stresses of the shaft accelerate its deterioration. Replacing this element preventively during a tune-up in the shipyard is considerably more economical than facing a breakdown while sailing with the axis in free movement.