Project Leader:	Professor Dr-Ing Horst Rulfs
Research Assistant:	Dipl-Ing C Gurr
Duration:	01.12.2002 - 30.10.2006

 

The propeller shaft of a ship rotates usually in oil-lubricated slide bearings located in the stern tube at the back of the ship hull. With increasing motor power also the loading on these bearings increases, affecting the safety of the ship. The design of these bearings follows basically empirical rules in which dynamic aspects are not taken into consideration.

In the last years and mostly during abrupt course changes at high ship velocities substantial damages have occurred on propeller slide bearings of passenger ships.First investigations indicated that the shaft under instationary operation during the maneuvre is pressed againgst the free ends of the stern tube bearing, i.e., areas with reduced loading capability due to the lubricating chambers there.

The knowledge over the behaviour of bearing systems for propeller shafts under instationary operation is at present very patchy. The significant role for the performance and the maneuvrability of a ship and the substantial expenses that result from such failures were the main motivations behind the present project.

Aim of the research was to improve the operation safety of the propeller bearing by studying in detail its instationary behaviour. For this, the loading and stressing of the propeller, the propeller shaft and the bearing under various manoever conditions were studied experimentally and numerically. The results were incorporated in the design procedures for stern tube bearings and sealings.