Vessel with a hydrodynamic duct of flow management at the bow thereof, said duct being composed of a horizontal wall portion extending on either side of the centerline of the bow of the vessel and a pair of lateral wall portions connected at their bottom with said horizontal wall portion, wherein said lateral wall portions and said horizontal wall portion have an airfoil section, and wherein said lateral wall portions extending upwardly at each side of the bow are forming together with the horizontal wall portion an area of flow within the duct entirely differentiated from the flow outside the duct, wherein said duct is further provided with at least one additional horizontal wall portion having an airfoil section such that in use, when the vessel is sailing, said additional horizontal wall portion remains fixedly positioned at the region of the waterline above said horizontal wall portion which remains always fixedly positioned at the bottom of the duct below the waterline, wherein the combination of said horizontal wall portion at the bottom of the duct below the waterline with said at least one additional horizontal wall portion at the region of the waterline together with the lateral wall portions that extend upwardly on either side of the bow and are connected at the ends of said horizontal wall portion and at the ends of said at least one additional horizontal wall portion, define a circumferentially closed duct that provides a cumulatively increased reduction of wave making resistances and reduction of the rated horsepower and fuel consumption for the propulsion of the vessel, characterized in that the leading edge of said at least one additional horizontal wall portion is located backwardly with regard to the leading edge of said horizontal wall portion and said at least one additional horizontal wall portion is smaller in size than said horizontal wall portion, such that said at least one additional horizontal wall portion having an airfoil section cooperates with the vectors of the surface waves produced by the sea in order to achieve an increase of the inlet velocity of the flow incident onto the leading edge of said at least one additional horizontal wall portion, wherein said at least one additional horizontal wall portion produces absorption of wave energy that is produced as a result of increased speed of flow through the leading edge of said additional horizontal wall portion. wherein said duct is further provided with at least one additional horizontal wall portion having an airfoil section such that in use, when the vessel is sailing, said additional horizontal wall portion remains fixedly positioned at the region of the waterline above said horizontal wall portion which remains always fixedly positioned at the bottom of the duct below the waterline, wherein the combination of said horizontal wall portion at the bottom of the duct below the waterline with said at least one additional horizontal wall portion at the region of the waterline together with the lateral wall portions that extend upwardly on either side of the bow and are connected at the ends of said horizontal wall portion and at the ends of said at least one additional horizontal wall portion, define a circumferentially closed duct that provides a cumulatively increased reduction of wave making resistances and reduction of the rated horsepower and fuel consumption for the propulsion of the vessel, characterized in that the leading edge of said at least one additional horizontal wall portion is located backwardly with regard to the leading edge of said horizontal wall portion and said at least one additional horizontal wall portion is smaller in size than said horizontal wall portion, such that said at least one additional horizontal wall portion having an airfoil section cooperates with the vectors of the surface waves produced by the sea in order to achieve an increase of the inlet velocity of the flow incident onto the leading edge of said at least one additional horizontal wall portion, wherein said at least one additional horizontal wall portion produces absorption of wave energy that is produced as a result of increased speed of flow through the leading edge of said additional horizontal wall portion.