Open water performance of Azipod ® propulsor at model scale is predicted by unsteady RANS CFD with SST (Menter) k-omega turbulence Gamma Transition model since Reynolds number Re is below 500 000 which is considered as critical Re for transition in external flows. The importance of turbulent parameters at inlet boundaries and Wall Y+ for Transition model are addressed and discussed. At ship scale, multiphase and free surface flow simulations for the ship hull and rotating propeller at the self-propulsion point at various ship speeds are performed by unsteady RANS CFD with SST (Menter) k-omega turbulence model. In this study, all the simulation are performed with the commercial CFD solver Simcenter StarCCM+. For both simulation approaches, simulated results are compared to experiments conducted at several model basins for validation. Several years ago, Siemens PLM (then CD-Adapco) added finite element solver capability to Simcenter StarCCM+ product family. Azipod ® propulsor is simulated in oblique flow at ship scale by two approaches: traditional method when first unsteady RANS CFD is used for simulating propeller thrust and torque and then pressure and wall shear stresses on propeller surfaces are exported at predefined time intervals from StarCCM+ and imported to third party software for stress FEM analysis or using fully coupled transient Fluid Structure Interaction (FSI) feature within StarCCM+. In the CFD analysis, SST (Menter) k-omega turbulence model is utilized. In this work, importance of data transfer and mapping between CFD and FEM meshes is addressed and stress distribution on propeller surfaces at several propeller radii are compared from two separate finite element analysis. Finally, comparison between benefits and drawbacks of these two approaches is discussed.