This paper presents the performance results of the numerical study on the three-dimensional rolling-type wave energy converter with the mooring system. The novel device combines an established and reliable mooring system, making it suitable for deeper sea utilisation. The shape of the device is based on the renowned Salter's Duck, which is capable for converting wave energy into mechanical energy through rolling back and forth. The results are obtained using the Panel Element Method package AQWA, based on linear wave theory and potential flow theory. The hydrodynamic behaviour of the device is assessed in the frequency domain, including the additional mass, the radiation damping and the wave exciting force. In the time domain, the coupling of the device motion and the dynamic response of the mooring system is performed, allowing comparisons with experimental work on a 1:16 scale model. The tension of the anchor chain is reported in detail. The relative capture width of the device under different wave conditions is also examined.