​Water lubricated stern tubes     
​Regulatory

​Unlimited tail shaft withdrawal survey intervals with Condition based maintenance notations
Avoid Risk

​Avoid the risk associated with operating vessels with oil lubrication by installing water lubricated tail shaft.
An oil leakage represent exposure towards; unexpected maintenance, loss of hire, and potentially fines
​Robust

​A water lubricated stern tube system designed with emphasis on; corrosion resistance, bearing material selection, and installation arrangement, produce a reliable system with long service life.

Condition monitoring enable timely maintenance planning 
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System components         
Propeller shaft bearing 
We offer two alternative bearing materials with different properties.
Material selection for an installation is based on a project specific evaluation of the acting loads and operational profile. 
Bearing material - Norden 788 Marine
Norden 788 Marine is among the worlds leading low friction  materials. The materials properties make it well suitable for use in a propeller shaft bearing arrangement. The wear and heat generation will occur during accelleration and decelleration of the shaft, low friction level reduce both these parameters and contribute to a long lifecycle of the bearing.
Norden 788 Marine is type approved for use in water lubricated stern tubes by leading classification societies.
Bearing material - Norden CM7
​Norden CM7 has been developed for use specifically in water lubricated shaft applications. It is a soft and ductile material which offer good wear life, abrasion resistance and shock load absorption. The material perform well in shafting arrangements where edge loading can be expected. 
​Norden CM7 is type approved for use in water lubricated stern tubes by leading classification societies.
Bearing carriers
All bearings can be supplied finished machined and ready for installation in stern tube,
or the bearings can be supplied with bearing carriers which is then choched directly into ships aft section.
Bearing carriers allow for split bearing segments that enable bearing renewal without pulling of the propeller shaft.

Material tubes
Unmachined material is available where onsite tailoring and machining is required.   ​
Water Filtration Unit
To ensure the bearings have optimum working conditions and to comply with regulatory requirements a filtration and lubrication unit is installed.

The unit is installed between the vessels seawater intake(s) and the stern tube. Large particles that can increase bearing wear are removed from the cooling water,  and cleaned water is flushed through the stern tube to allow hydrodynamic operation of shaft. 
The water flow is monitored per rule and operator requirement for pressure, temperature and quantity.

Where required, the unit can be extended with a hydrostatic module giving extra lift to shaft during operation at speeds below hydrodynamic condition. 

The unit can be configured to meet a any specification.

   
Bearing wear down sensor
An integral part for condition monitoring and maintenance planning is knowing the bearing wear status. 

The WDS-10 wear down sensor is type approved by DNVGL and measure and trend bearing wear development. 

The sensor can be connected to the Water Filtration Units alarm system, and be supplied as a stand alone logging system.