Due to the increasing of fuel prices, it is a challenge for Naval Architects to design a ship dealing with reducing total resistance (𝑅𝑇) through optimizing the catamaran hull and her lateral configuration (S/L), which directly lead to increase the ship’s propulsion efficiency. Here, a numerical optimization modelling has been developed using a genetic algorithm (GA) approach to assess the optimum dimension of the hull form and S/L in which these are able to reduce primarily the value of RT. The results revealed that the optimum length, beam and draft of hull has resulted in sufficient reduction of 𝑅𝑇 by 10.2 %, 8.5% and 8.8%, respectively. As compared with the existing model, the optimum S/L resulted in the optimum hydrodynamic performance of the Catamaran, where the value of RT sufficiently decreased by 7.6%. In general, this can be explained by the fact that the interference factor between two demi-hulls gradually decrease and well-as the pressure resistance acting on each of the two demi-hulls.