A combination of cartesian-grid methods and volume-offluid methods is used to simulate breaking waves around ships and the resulting hydrodynamic forces. A surface panelization of a ship hull is used as input to automatically generate an immersed-boundary representation of the geometry on a cartesian grid. No additional gridding beyond what is already used in potential-flow methods and hydrostatics calculations is required. The volumeof- fluid portion of the numerical algorithm is used to capture the free-surface interface, including the breaking of waves, the formation of spray, and the entrainment of air. The numerical scheme is implemented on a parallel computer. The numerical simulations are compared to analytical solutions and experimental measurements. Together, the ease of input and usage, the ability to model and resolve complex free-surface phenomena, and the speed of the numerical algorithm provide a robust capability for simulating the free-surface disturbances near a ship.@en