Due to global warming, all industries must do everything they can to prevent temperature increases. In this bachelor thesis, the reader will get a description of how the marine industry is tackling the environmental problem and more precisely what a vessel can be equipped with to reduce fuel consumption.   The thesis deals with how different energy saving devices (ESD) affect the propulsion efficiency of a chemtanker sailing on the sea. The thesis will address the following three different concept: Pre-swirl stator, Pre-swirl duct, Pre-duct. The work will step-by-step describe the different optimization parameters that need to be adjusted and what impact these parameters have on the wake field of the propeller plane.  The work addresses some different devices that will reduce the fuel consumption of ships and that these devices not only reduce fuel consumption, but also have a positive impact on cavitation. The result of this thesis was that ESD will reduce the power needed to reach the desired speed of the vessel and after post-processing was made, the best result, which was Pre-swirl stator, showed an energy saving percentage of as much as 3.15% and the risk of cavity occurring at the propeller tip was also reduced.