Out of damage cases reported to DNV, the most common machinery related damages experienced are those to propeller shaft- and engine bearings. Out of these damages, the vast majority of the damages occur in the aft most bearing. The main reason for the damages in this bearing is collapse of lubrication in the bearing caused by significant lateral forces and moments generated by the propeller. Historically, these propeller forces have not been accounted for in alignment and bearing design. In order to quantify the effects of the propeller forces on the shaft/bearing interaction, DNV has carried out a series of research projects where the lateral propeller forces have been measured directly on different vessel types in both steady state and transient operation. Analysis was carried out to investigate the effect of the propeller loads on the stern bearings of the vessel. The measurements have also been used as a benchmark to assess the predictive ability of current analytical methods. The results clearly illustrate the importance of being able to accurately predict lateral propeller forces in both steady state and transient conditions due to their significant effect on the bearing performance.