Carstensen, BjörnBjörnCarstensen2025-08-192025-08-192025-07-31Ship Technology Research (in Press): (2025)https://hdl.handle.net/11420/57046Due to the growing requirements on energy efficiency of ships, certain problems and challenges arise for the design of rudders and propellers. For the rudder, the focus changes for many ship types from solely being a manoeuvring device to positively influencing the propulsion. This paper summarizes a hybrid calculation method for the calculation of rudder forces and for the evaluation of the bidirectional interaction between propeller and rudder for the early design stage. The new hybrid calculation method couples a lifting line approach for multi-component-propulsors with a panel method and a two-dimensional boundary layer method. The calculation results of the developed method are validated with measurements from several model tests. Finally, an application for full-scale predictions is presented.en2056-71112025Taylor & Francishttps://creativecommons.org/licenses/by/4.0/boundary element method | boundary layer method | hybrid calculation method | lifting line | Propeller–rudder–interactionTechnology::620: Engineering::620.1: Engineering Mechanics and Materials ScienceTechnology::623: Military Engineering and Marine EngineeringNatural Sciences and Mathematics::530: PhysicsJournal Articlehttps://doi.org/10.15480/882.1579110.1080/09377255.2025.253753810.15480/882.15791Journal Article