This paper concerns experimental measurements of the interaction of a taut moored floating body,
representing a wave energy converter in survivability mode, with extreme waves. Focussed wave groups,
based initially on NewWave theory, are used to generate the extreme waves, with crest amplitude
exceeding the mooring's design capacity. Two data sets are presented and discussed. In the first the
influence of wave steepness on model response and mooring load is investigated using non-breaking
focussed wave groups. In the second the influence of wave breaking location is investigated using a
plunging breaking wave. Both data sets exhibit snatch loading as the extension of the mooring is
exceeded. The magnitude of this loading is not found to be strongly dependent on wave steepness, while
the following motion response of the body is. Breaking location has a much greater effect than wave
steepness on the magnitude of the mooring load, while significant influence of the body motion and
displacement on the mooring load is demonstrated. Evidence is provided that the use of individual
focussed wave groups is inadequate to assess fully the extreme loads experienced by a taut moored WEC
due to the demonstrated dependence of mooring load on the body's motion and displacement.
& 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license