Disclosed is a system for providing an air lubricating layer between the hull of a vessel and the water flowing under the hull as the vessel is moving through the water, including an air cavity and a wave deflector having a planar bottom surface which faces the interface plane and extends parallel thereto and is arranged in an air cavity of the air lubrication system at a distance of 2-15 cm from the interface plane, wherein the bottom surface has a peripheral edge that is spaced apart from the sidewalls by a gap having a width of 0.5-15 cm, wherein, when viewed in projection onto a plane wherein the planar bottom surface extends, at least 85% of the area of the opening is covered by the wave deflector and/or the planar bottom surface thereof, more preferably at least 90%, and most preferably at least 95%.