This paper presents a methodology for assessing the structural forces applied to the Wavestar wave energy converter. Devices such as Wavestar use an offshore support structure as a fixed reference for several floaters. The floaters transfer wave loads to the support structure. This complex loading is investigated here using a methodology which fully integrates the hydrodynamic loads and the structural characteristics of the Wavestar. The influence of several parameters on structural deflections and forces have been investigated.