This thesis examines the possibility of installing a hydro-generator in the hull of a large sailing ship. Using computational fluid dynamics (CFD), it is possible to calculate and analyze hydrodynamic characteristics with sufficient precision in a significantly shorter time compared to experiments and model testing. The first part of the thesis explains the possibilities of all relevant methods and parameters for successful numerical simulations, such as finite volume method, domain discretization, mathematical models, turbulence models, RANS equations, fluid volume fraction method and boundary layer and corresponding boundary conditions. The resistance results of the sail ship hull form, obtained by applying computational fluid dynamics, were compared to the available experimental results for the purpose of method validation. The same procedure was used to calculate the flow characteristics and to determine the hydrodynamic performance of sail ship with a modified stern shape. As similar installations on ships are not known, the initial dimensions of the tunnels and openings in the hull are taken according to the available dimensions of the existing water jet propulsors. Hydrodynamic calculations were performed as if it were the installation of such propulsors. In this way, data on flow, velocity and pressure fields at hull locations were obtained. The analysis of these data can determine the best location for the location of openings and tunnels from the point of view of lower resistance of the ship when installing either water jet propulsors or hydro-generators.