Vessel with improved hydrodynamic performance

摘要

AbstractPlaning vessels of improved performance capability and methods for improvingsuch performance and fails which may be associated with a planing vessels forproviding improved performance capability. A dynamic downward forcegenerated as the vessel (1) moves through water, preferably by a foil (3), isimposed on the vessel, with the locus of the force positioned in the transversedirection, at the longitudinal vertical centerline plane of the vessel. In thelongitudinal direction the locus of the dynamic force is positioned, relative to theother forces acting fore-to-aft on the vessel, to decrease the trim angle of thevessel, desirably to less than two degrees. Vessel wetted surface configurationsare provided for stable and efficient operation at low trim angles, including thefollowing. A deep draft, fine entrance (32) which minimizes rise at the bowexperienced with conventional planing vessels and assists in maintaininglaminarity of flow at the planing surfaces. A foil (31) extending along thebowpeak below the waterline and spaced forwardly thereof to streamline theflow passing the bow to thereby decrease spray and turbulence. A skeg (32)extending downward at the bottom of the hull at the entrance along thelongitudinal centerline plane with improves directional stability and alsoassists in maintaining flow laminarity. A sweptback wing located at theentrance, preferably mounted at the lower margin of the skeg positioned with anangle of attack which generates an upward force to improve the vessel stabilityagainst pitch and yaw in disturbed water An aftmidships planing floor (11)having a rise from midships to the stern trailing edge desirably from 50% to 100%of the midships draft improves the stability of the vessel when operated at trim.A release floor (21) extending aftward 5 to 25% of the waterline length of thevessel, preferably from a transverse step (4), and rising over this length 10 to50% of the midships draft to a transverse trailing edge (22). The trailing edge andthe release floor, in the transverse direction, are parallel with base plane of thevessel. The pressure release floor reduces the pressure on the aftward flow toseparation at the trailing edge in a gradual and uniform manner which reducesdrag. Chine lines (12) at the margins of the aft planing floor are provided withfins which extend aftwardly and upwardly of the stern trailing edge to effect asmooth flow separation. The foil to generate a downward force in the flowdesirably is positioned below the stern trailing edge and contoured to produceminimum induced drag and to divert the flow at its trailing edge downwardly soas to reduce turbulence and drag at the stern.