A flat-bottomed vessel and a method for controlling the length of at least one air cavity

摘要

The invention relates to a flat-bottomed vessel (1) for transporting persons or goods, the vessel comprising a drag reduction system attached to the bottom (2) of the vessel. The drag reduction system comprises: two or more turbulence members (3) extending perpendicular to the longitudinal direction of the vessel for generating an area with turbulent flow downstream to the turbulence members at the bottom of the vessel during movement thereof, and for each turbulence member an air injector (6) adapted to inject an air flow at or near to the turbulence members. The drag reduction system further comprises a keel (4) adjacent to both sides of the turbulence members (3). The bottom of the vessel is flat without cavities and the turbulence members are ridges sealingly attached to the bottom of the vessel between the keels, and the turbulence members extend 2.5-25 mm from the bottom of the vessel.