The energy ship is a concept for offshore wind energy capture which has receveid very little attention until today. Particularly, there had not been yet an experimental proof-of-concept. In order to address this issue, an experimental platform has been developed at Centrale Nantes. It consists in a 5.5 m long catamaran equipped with a 240 mm diameter water turbine. The platform was tested in July 2019 on the river Erdre (France). Results show that it is essential to optimize the water turbine induced drag in order to maximize energy production; and that the energy ship concept is able to produce significant amounts of energy.