A dynamic Velocity Prediction Program (VPP) integrated in a Computational Fluid Dynamics (CFD) code is described. The program computes aerodynamic forces and directly inputs them to the CFD solver, which solves both the flow and the motions of the boat. The VPP code controls the heel of the boat and optimises a sail power parameter for a given True Wind Angle and True Wind Speed. This approach allows naval architects to swiftly and precisely compare several yacht designs in real sailing configurations using only a few CFD computations. Several advanced features of this program are covered in this paper including convergence criteria, automatic grid refinement, foil fluidstructure interaction, multiple aerodynamics models and rudder control.