In recent years, the need for a quantification of “maneuvering in waves” has increased due to both requirements for heading and track keeping of naval hulls, and to quantify the ability of low-powered ships to recover and keep the (presumably safe) head seas heading in adverse weather. To address these requirements, the CRS has been working since 2011 on a new time domain simulation tool able to predict the ship’s sustained speed, track and drift angle in wind and wave conditions with sufficient accuracy. Due to the difficulty in accurately combining the wave frequency forces with the maneuvering forces, a reformulated simulation tool was developed which only considers the low frequency wave drift forces and the maneuvering forces. The present paper presents how this new approach (ManWav) performs compare to the experimental results and compare to a fully coupled semi-nonlinear time domain tool (FREDYN). To assess the performances of this approach, an extensive validation test campaign was carried out on the 5415M model. This test campaign included captive and free sailing maneuvering tests in calm water, in regular and irregular waves for multiple wave directions and ship speeds.