Shafting alignment is the most important, demanding and complex process, that is performed, on the basis of design values, during the assembly of a modern marine propulsion system. This system is exposed to various workloads throughout the entire service life of the ship, so it has to be mounted and aligned in the way that it meets all the possible service loading cases. In order to prolong the life span and smooth operation, it is essential that the propulsion system of the ship is properly dimensioned. The basic requirement for proper operation and performance of its function in different operating conditions is the proper construction, installation and testing on board. The procedure and the calculation of shafting alignment are of great importance in the installation process. By developing computer programs and conducting computer simulations, shipbuilders are able to accurately design ship propulsion systems from the point of view of deformation and stress. In this paper, the SKF ShaftDesigner computer program will be used for computer simulation of shaft alignment, where the paper itself presents some of its advantages.