CFD-based numerical wave tank (CNWT) models, are a useful tool for the analysis of wave energy converters (WECs). During the development of a CNWT, model validation is important, to prove theaccuracy of the numerical solution. This paper presents a validation study of a CNWT model for the 1:10 scale Wavestar point-absorber device. The previous studies reported by Ransley et al. (2017) and Windt et al. (2018b)are extended in this paper, by including cases in which the power-take off (PTO) system is engaged. In this study, the PTO is represented as a simple linear damping term in the CNWT WEC model, providing a first approximation to the full PTO dynamics, to be included in the CNWT in future work. The numerical results, for surface elevation and device position, are shown to compare well with the experimental measurements.