COLLARIN EJE 28mm. USA (ZN)

Function and technical context

The 28 mm shaft collar is a component of the tail shaft transmission and sealing system on boats with outboard or tail drive propulsion. Made of zinc (ZN), it acts simultaneously as a fastening and axial retention element for the propeller shaft and as an integrated sacrificial anode, protecting the metal assembly against galvanic corrosion in salt and fresh water. Its design in accordance with the USA standard guarantees dimensional compatibility with the most widespread propulsion systems on the North American market. If this collar wears out or loses zinc mass due to corrosion, the shaft is exposed to electrolysis, which can cause accelerated deterioration of the shaft, bushing and adjacent metal components, compromising the integrity of the propulsion line.

When to replace this part?

Collared zinc anodes should be inspected at least once a season and replaced when they have lost approximately 50% of their mass, have a badly corroded, uneven surface, or show signs of dislodgement. If the collar loses its cathodic protection capability, visible pitting or erosion will appear on the propeller shaft, as well as corrosion on the propeller and hub. As a preventive rule in saltwater navigation or in areas with high electrical conductivity, it is recommended to replace the collar at each tune-up at the beginning of the season; A collar in poor condition can lead to the complete replacement of the shaft, a much higher cost repair.

Compatibility table