Aim of this paper is to analyse the power and hydraulic performance of a floating Wave Energy Converter with the purpose at optimising its design for installation in arrays. The paper presents new experiments carried out in 1:30 scale on a single device of the Wave Activated Body type in the deep-water wave tank at Aalborg University. Power production and wave transmission were examined by changing the mooring system, the wave attack and the device orientation with respect to the incoming waves.. To assure the best performance the device size may be "tuned" based on the local peak wave length and the mooring system should be selected to allow the device for large movements. (C) 2013 Elsevier Ltd. All rights reserved.