Assessing the manoeuvring performances of a ship early in the design stage is becoming ever more important, especially now that wind-assisted propulsion is radically increasing in popularity as a measure to reduce fuel consumption. For conventionally propelled vessels most of the forces are in the longitudinal direction. Some, relatively small, drift angles and rudder angles are encountered in order to compensate for side forces due to environmental conditions. For a wind-propelled vessel on the other hand, side forces are an inevitable consequence of the propulsion choice and it is of utmost importance to balance these side forces with a matching hydrodynamic design to efficiently propel the vessel forward avoiding travelling for longer periods of time. In order to counteract those large side forces, it is necessary to add underwater appendages. Their position along the hull will determine the centre of lateral resistance (CLR) that needs to be related to the aerodynamic centre of effort (CoE) in order to achieve a balanced ship. The research herein described, compares towing tank captive tests with Virtual Captive Tests (VCT) derived from Computational Fluid Dynamics (CFD) simulations and the effects of generated side forces and moments when the inflow angles are varied. Adding a set of diagonal foils to the hull, in the investigated case reduces the leeway angle of approximately 2 degrees in close-hauled conditions.