Our field of expertise

Propellor shaft reinforcement

Saltwater has been contracted to research propellor shaft problems.

An inspection has revealed problems with the Aurora-G’s propeller shafts. The problems consist of excessive wear and vibration of the propeller shafts. Calculations showed that these problems are caused by a lack of rigidity in the propeller shaft support. Calculations by a propeller shaft specialist showed that the propeller shaft support needs to be stiffened by a factor of 20. An important element in the design of the reinforcements is that the water flow to the propellers is not disturbed. To determine the correct solution, the original situation was first modelled to determine the displacement. The reinforcements were then modelled, and the new stiffness was checked with a FEM analysis.

Drawings of the propellor shafts
Propellor shaft tunnel beneath the Aurora-G
Propellor shafts beneath the Aurora-G

New stability booklet 

As no digital drawings of the hull were available, the hull shape was scanned using a 3D Lidar scanner. Production drawings were made using the results of the 3D scan. By using the 3D scan results, the correct fit of all parts was ensured. Since the installation of the reinforcements and other modifications to the vessel changed the lightship weight, centre of gravity and centre of buoyancy and inclination test was required by the classification society. This inclination test has also been executed by our naval architects. 

The results of the inclination tests are used to create a new stability booklet. The stability booklet included: Loading conditions, Hydrostatic tables for both the vessel and the tanks, Gz-curves and max KG-curves. This project shows a combination of different naval architecture aspects which are just a few of our portfolio. Each of the steps in this project has been executed in close cooperation with the client, shipyard and classification society.  


Specific project data

Project information

Scope of work 

  • FEM calculation to determine the rigidity of the structure 
  • 3D modelling of ship shape based on 3D scan 
  • Modelling of new construction parts 
  • 2D production drawings of new construction 
  • Inclination test 


  • Calculation report 
  • Construction drawings 
  • Inclination test report 
  • Stability booklet