Rudderpropellers for Tugs - developing the state of the art

摘要

Rudderpropellers are widely accepted as the state of the art in tug propulsion. This does not mean however, that the technology of these successful propulsion devices and the way they are selected and customised is not undergoing continuous development. The development of new rudderpropeller models makes use of the most advanced design tools available to engineers today. Computational Fluid Dynamics and model tests help to optimise the hydrodynamics. Finite Element Analysis is the tool of choice to design mechanical rigidity with minimum weight. Detailed strength and life time calculation are performed for each bearing and gear. But not all problems can be solved on the basis of theory. It takes an experienced design team to finally get homogeneous engineering solution for such a complex system. Major steps in the design of a typical tug propulsor are shown. In a separate section of the presentation a description of Schottel's efforts to meet the demand for ever increasing bollard pull is given. Systematic protracted work led to a new highly efficient nozzle system ready for introduction into the market. The last part deals briefly with the torsional vibration analysis for the power transmission line, which is performed for each project.