The recent growth in propulsive power of ships has resulted in cases of severe damage to the stern tube bearings and the sealing rings. In most cases, the shaft alignment analysis has been still only carried out under non-operating condition. This static alignment condition is considerably effected by some external factors, such as propeller forces and moments, double bottom deformations, bearing flexibility and thermal influence.
The paper discusses the theroretical and experimental study of the dynamic shaft alignment in service loading of stern tube bearings. The distortion and bowing of the tail shaft under the influence of the propeller forces and moments is taken into account of the analysis of the stern tube bearing performances.