Patent ID: 6148756
Filing Date: 2000-11-21
Classification: B63B,Y02T

Abstract:
A method for dynamically controlling a trim angle of a fast moving, planing or semi-planing ship hull under propulsion at cruising speed, the ship hull having a length and a load, the method comprising the steps of:providing a hydrofoil with a sectional profile of a wing, the hydrofoil having a span width, a chord length and a lift, such that the wing-shaped hydrofoil, when forced through water provides a lift force which is dimensioned relative to the load of the ship for balancing a fore part of the ship above the water at cruising speed;arranging the hydrofoil pivotally adjustable and fully submerged in a stem portion of the ship hull, and controlling an angle of attack of the hydrofoil relative to water flow when the ship is under propulsion, therebycontrolling a submersion depth of the hydrofoil by adjusting its angle of attack in response to a detected trim position of the ship;generating a wake by the submerged hydrofoil at cruising speed, the wake having a length related to the chord length, a width related to the span width, and a depth related to the load, balanced by the hydrofoil, andadjusting the hydrofoil to achieve the submersion depth, so that the chord length, span width and lift of the hydrofoil is effective, through said adjustment of the attack angle, for manipulating the wake to intersect with a stern portion of a bottom of the ship hull at an intersection angle, the wake balancing the ship load in said stern portion of the ship, while supporting the stern portion at a height related to the submerged depth of the hydro-foil.