Occurence of encountered dangerous waves

Sofia Åberg, Igor Rychlik and Ross Leadbetter

Abstract:: Distributions of wave characteristics of ocean waves, such as slope, amplitude or wavelength, are an important tool in the study of ship stability. In such studies, spatial properties of the sea surface at fixed time points are often considered, although it would be more interesting to study the properties of those waves that a ship actually encounters when it sails on the ocean. In this paper we derive distributions for several wave characteristics that can be related to steepness of waves for two different cases, namely for waves observed at a fixed time point and for waves encountering a ship. The distributions obtained in these two ways will not be the same and it turns out that the difference between them can be explained in terms of wave velocity.