In order to achieve reductions in ship emissions and operational costs while complying with increasingly stringent regulations, ship owners need to consider combining multiple efficiency enhancing strategies where synergistic benefits are possible. One such option is to couple wind assistance with speed reduction. Realizing this solution’s maximum potential requires both an experimental characterization of the forces present when the vessel is sailing as well as a numerical tool to analyse instantaneous energy consumption at specific conditions to suggest optimal operating strategies over a route. Therefore, this paper focuses on processing strain gauge measurements for real-world wind propulsion units, coupled with a numerical modelling tool for a wind-assisted container vessel. These measurements are then integrated into the numerical model and simulations are conducted to suggest improved operating strategies for increased fuel efficiency of a vessel across different speeds and along a route while considering real-world wind conditions. The results suggest that an increased travel time through speed reduction of approximately 8% can result in a fuel consumption decrease of nearly 16% due to the reduction in ship resistance and the increasing share of propulsive thrust provided by wind-assistance.