It is important that the lubricant quality is maintained:
For an oil lubricated bearing arrangement that means clean filtered oil that is regularly sampled and changed at the correct service interval. It also means good maintenance and monitoring of the aft seal performance to avoid any seawater ingress into the bearings lubricating oil.
For a water lubricated bearing arrangement that means, clean filtered seawater pumped to the Sterntube at a flow rate at least that recommended by the maker.
If monitoring and maintenance protocols are carried out, then the bearings should last the life of the vessel. Of course, exceptional circumstances can occur leading to accelerated wear or failure of the bearings. In those situations, replacement is required.
In most cases bearing replacement require withdrawal of the tail shaft to gain access to the Sterntube and allow bearing removal and refitting. However, some composite bearing designs are not tubes but two half shells forming a tube – these can be exchanged with the tail shaft in position.
Whatever your bearing needs, ATZ have extensive experience with both types and can supply new bearings or provide advice on the operation, maintenance and troubleshooting of your equipment.