Water to lubricate the stern tube bearing is fed through the seal casing. This provides the sealing pressure (force) and lubrication required by the seal ring to effectively contact the liner. Pressure and flow meters are usually connected to the seal assembly to ensure and monitor proper operation. The seal ring requires water for lubrication and therefore some small amount of water leakage is to be expected. A significant amount of water leakage indicates a problem (i.e. wear on the seal ring or liner) requiring attention.

The liner is a split design allowing easy removal once the inflatable ring is activated. The spare seal ring slides into place, liner surface smoothed if necessary and unit reassembled.

Each vessel will have unique results based on the particular vessel and its operating environment. Generally, with proper installation and establishment of a simple monitoring/maintenance plan, years of trouble-free operation are the standard.