In the current paper, a novel framework based on 2D+T theory and oblique impact of a wedge section is developed for modelling the steady yawed planing motion of hard-chine hulls. The added mass theory is also utilized to compute the 2D forces acting on the wedge during the oblique impact. By integrating the 2D forces over the entire length of the boat, 3D forces in horizontal and transverse planes are obtained. Meanwhile, a procedure is presented for finding the running attitudes of a yawed planing hull. The hydrodynamic forces acting on the hull are computed by satisfying the dynamic equilibrium in heave and pitch directions. Predicted running attitudes have been compared against experimental data and fair agreement between both results has been achieved. In addition, the accuracy of the proposed method in prediction of the forces and moments in horizontal plane is assessed.