Abstract
With the aim to more precisely calculate the tails of the probability distribution for the sea state parameters, it is proposed in this paper to fit the significant wave height data utilising a Generalised Gamma distribution. Based on the fittings to two ocean wave data sets, important findings have been obtained that the proposed method has very high accuracy in fitting sea state parameter probability distribution tails.
Subsequent research has been carried out to derive a 50-year environmental contour line based on the proposed Generalised Gamma distribution and the Clayton copula theories. The advantages of predicting the long-term design force values for wave energy converters based on a more trustworthy environmental contour line derived using our proposed method has been finally demonstrated through a real world engineering example.