STG Symposium "Selected Topics on Strength, Vibrations and Noise"

The Influence of Propeller Retrofits in the Torsional Vibration Behaviour of Shafting in Marine Vessels

Kevin Lal, Mecklenburger Metallguss GmbH, Waren

In the modern shipping industry, the slow steaming of vessels is a well-known scenario with a main focus to reduce the specific fuel consumption and emissions. This could be achieved by an optimised design operation of the vessels making them to operate more efficiently at lower speeds. Marine engine optimisation measures like engine power limitation offers this possibility to attain a lower ship speed but this measure often requires further modifications or replacements in the ship propulsion system itself. Retrofitting propellers designed for the new optimum engine design load is one of the suitable options that can be carried out to meet the new operation requirements of the vessels. However, replacing the current propeller with a new one obviously affects the dynamic behaviour of the complete shafting system, especially the torsional vibration behaviour. MMG a prominent player in the production of fixed pitch propellers, highlights the impact of energy efficient and light weight propellers in the torsional vibration behaviour of a propulsion shafting line.