The aim of this paper is to determine which wave
conditions are inducing extreme mooring loads on a highly
dynamically responding moored structure. Currently, the design
of a mooring system for a typical oil and gas offshore structure is
based on the prediction of the extreme mooring loads for a
limited number of wave conditions along the envelope of a wave
scatter diagram. During the design process, an inappropriate
choice of wave conditions could lead to an incorrect estimation of
extreme mooring loads, which may result either in the loss of the
mooring system or in a costly overdesign.
This paper draws on mooring tensions and wave conditions that
have been recorded at a mooring test facility using a multi-leg
catenary mooring system. The mooring loads have been assessed
to identify extreme mooring loads, which have been analysed in
respect to the corresponding wave conditions. Further, joint
probability distributions of wave conditions that results in
extreme mooring loads have been determined.
The most important finding is that extreme mooring loads were
not necessarily identified to occur on the envelope of the wave
climate parameter scatter diagram
