Marine Propeller Reverse Engineering and Retrofitting

Abstract The motivation for this study arose from the practical task to equip a new built small vessel with a used propeller. A particular challenge was the lack of documentation or a data sheet for the propeller and the demanding application in dynamic positioning (DP) operations. The idea to tackle this problem was to conduct a reverse engineering analysis of the propeller and use computational fluid dynamics (CFD) to predict the performance parameter and study the potential improvement for DP operation by retrofitting the propeller with a nozzle. For this purpose, first a 3D scanner is used to generate a tessellated surface geometry of the propeller. The following geometric analysis procedure allows to determine the propeller design parameter that are then used to to create a propeller CAD model. This smooth and closed CAD file can then be used in a classical CFD open water test scenario to determine its performance parameter and in a Bollard pull, to test it for its usability for DP. In a final step, the thruster will be equipped with a propeller nozzle to study the potential performance improvement. In addition to solving a practical engineering problem, the study will contribute an automated procedure for extracting a CFD suitable CAD geometry from 3D scans and help to establishing a CFD setup to study propeller nozzle performance.