In most of methods and among Savitsky's semi experimental method, deadrise angle is assumed constant or used its amount in cross section of gravity center. In fact the deadrise angle of high speed craft is variable in longitudinal direction of hull. According to pervious assumptions for the deadrise angle, real physic of Problem didn’t model. In this paper, hydrodynamic resistance per weight is calculated by development of Savitsky’s semi experimental method and has been shown that results of present method have more accurate than results of Savitsky’s semi experimental method at comparison with empirical results. Also results of present method are good agreement with the empirical results over a wide range of volumetric Froude numbers. Then, optimum effective parameters such as position of gravity center, beam and rate of deadrise angle variation is determined by using genetic algorithm method. Objective function is considered resistance per weight in optimization that it is calculated in first part of the paper. Dynamic and static stability are as constraints of optimization that dynamic stability includes transverse dynamic stability and porpoising. Finally, Optimum answers group is presented for use of naval architect in concept design of monohull high speed craft.