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1. What is the bearing material used for propeller shafts?

Thordon manufactures 4 grades of propeller shaft bearings for different operating environments – COMPAC for blue water operation, XL and SXL for varying degrees of abrasives and RiverTough for the most abrasive water conditions.  They are proprietary synthetic elastomeric polymer alloys combining the best properties of plastic with the toughness and abrasion resistance of rubber. See the Thordon Bearing Grade and Configuration Selection Chart.

2. What makes COMPAC bearings unique compared to most other water lubricated propeller shaft bearings?

COMPAC bearings are designed without grooves in the lower half (the loaded part of the bearing). This promotes hydrodynamic operation at lower shaft speeds thus, giving quiet operation with low shaft drag.

3. What is the minimum water flow to Thordon Propeller Shaft Bearings?

0.15 litres/minute/mm (1 U.S.Gallon/minute/inch) of shaft diameter.  Thordon also requires less water flow than rubber.

4. Can bronze liners be used with COMPAC propeller shaft bearings?

Yes – We recommend gunmetal, inconel and copper-nickel. Be wary of aluminum-bronze however as the surface may degrade creating a rough surface.

5. What is the best liner to use in a dirty water-operating environment?

The best liner to use in dirty water environment is a Nickel Chrome Boron coated liner with a surface hardness greater than 50 Rockwell C.

6. What is the maximum operating pressure for Thordon stern tube bearings?

The maximum operating pressure is 0.6 MPa (87 psi), which is limited by Classification Societies.

7. Can we use after engine cooling water to flush and lubricate the stern tube?

Not recommended, as the temperature from engine cooler can be hotter than allowable for the bearing.