Distance ring or Spacer ring for your stern tube seal system
What is a stern tube distance ring?
A stern tube distance ring, also known as a spacer ring, is an important component in many oil-lubricated stern tube sealing systems. RM Propulsion distance rings are designed to support efficient maintenance and help extend the service life of stern tube seal arrangements.
In lip-type stern tube systems, the seals operate on a chrome steel liner mounted around the propeller shaft. During normal operation, the seal lips gradually create wear grooves on the liner surface. Because proper sealing performance depends on a smooth and undamaged contact area, the seals must eventually be repositioned once the wear becomes excessive.
This is achieved by installing or removing a distance ring between the stern tube and the seal housing. By shifting the seal housing slightly forward or aft, the seal lips can run on a fresh, unworn section of the liner. This helps maintain reliable sealing performance, proper lubrication, and reduced risk of leakage.
After multiple overhaul periods, when grooves are present on several contact surfaces, the chrome steel liner can be removed and re-machined to restore a smooth sealing surface for continued operation.
