This paper is part of the Bassin Numérique project managed by IRT Jules Verne (French Institute in Research and Technology in Advanced Manufacturing Technologies for Composite, Metallic and Hybrid Structures). The authors wish to associate the industrial and academic partners of this project; respectively DCNS Research/SIREHNA, HYDROCEAN, STX France, Bureau Veritas. Abstract. A numerical towing tank needs to efficiently estimate the ship performances in both calm water and in regular waves. The knowledge of ship performances are mandatory during the design phases in order to provide architects with values helping in technological choices. In this context, numerical towing tanks appear as a more versatile solution than time consuming and costly model tests. The French Technical Research Institute IRT Jules Verne conducts studies to assess and validate methodologies based on CFD simulations to evaluate added resistance in regular waves. The present work conducted in the "Bassin Numérique" project provides a preliminary sensitivity analysis which aims to validate the numerical settings necessary to model the wave propagation. The main result of this preliminary study enables to specify accurate meshes for wave propagation. The present paper focuses on the validation study done by three different members of the IRT Jules Verne using three CFD solvers on four test cases: one static vertical cylinder [1] and three ships in head wave condition [2], [3] and [4]. For each case, numerical results are compared with towing tank experiments in terms of added resistance and motions. The different wave conditions and test cases allow covering the wide range of encountered wave frequencies and dealing separately with the cases of diffraction at zero speed, diffraction with forward speed and finally including radiation. Most of the results correctly fit the experimental data, especially in terms of heave and pitch. The added resistance is also accurately simulated for sufficiently high wave lengths.