Springing as a nautical term refers to global resonant hull girder vibrations induced by continuous wave loading. When the global hull girder vibrations occur as a result of an impulsive wave loading, for example a wave slam at the bow or stern , the phenomenon is denoted by the term whipping. Springing is a resonance phenomenon, and it can occur when the natural frequency of the 2-node vertical vibration of the ship equals the wave encounter frequency or a multiple therefrom. Whipping is a transient phenomenon of the same hull girder vibrations due to excessive impulsive loading in the bow or stern of the vessel. The 2-node natural frequency is the lowest and thereby the most dominant resonant mode leading to hull girder stress variations, though in theory higher vibration modes will be excited as well.