XFlow provides a virtual water channel module for free surface simulations. It can be used to analyze the flow around ship hulls, predict their resistance, seakeeping, loads on components, and the downstream wake of both surface and submerged watercraft. The adaptive refinement algorithm of XFlow can also detect and refine dynamically and automatically the ship wake and the free-surface of the fluid. For sailing boats, the multiphase solvers of XFlow allows both hydrodynamic analysis on the boat and aerodynamic analysis on the sail to be performed at the same time.