Why can steep short waves occur at a ship waterline and how to filter them in a practical way

Abstract If no filter is applied, steep short waves appear at the waterline of a ship – in the vicinity of the fore shoulder – at Froude numbers smaller than about 0.35. These short waves are shown to correspond to the divergent waves created by the ship bow. A practical method for effectively filtering steep short shoulder and midship waves, which are inconsequential and likely unrealistic, is given. This filter has no adverse effect on the wave drag and the hydrodynamic lift and pitch-moment experienced by the ship. Moreover, it is particularly simple as it is explicitly defined in terms of the Froude number and the hull geometry, and can easily be implemented.