comparison of hydrodynamic performance of a monohull planing vessel equipped by combined transverse step and transom wedge with a no appendage model: an experimental study

One of the most well-known strategies to eliminate or reduce the longitudinal instabilities in planing hull, is to reduce the trim of the craft. in the current study, porpoising is controlled through creating a transverse step, and the combination of adding a wedge to the stern and transverse step in the vessel. usually, performance of stepped boats is not suitable in pre-planing regime. however, through the proposed method, stepped model performance can be improved prior to the planing regime. the investigated mcraft is a 2.56 m long monohull high speed model with speed range of 1,3,5,7 and 9 m/s. the obtained results indicated that best performance was acquired by the step and wedge model at the beginning of the planing regime. from 3 to 7 m/s, drag of stepped and wedged models had the lowest value and above 7 m/s and at 9 m/s, the stepped model has the lowest resistance. by combining the step and wedge models, the largest reduction of the rim angel was occurred (at speeds of 3 to 9 m/s). thus, through combining the step and wedge models the poor performance of the stepped models could be improved prior to the planing regime.