Study on reduction of wave-making resistance in multiple load conditions using real-coded genetic algorithm

Practical ships have different operating speeds, draft and trim in multiple load conditions. Therefore, in the hull form improvement, it is necessary to develop a different hull form in substance for every condition, from a viewpoint of hydrodynamics. The present paper proposes a hull form optimization method for reducing wavemaking resistance using the real-coded genetic algorithms in multiple load conditions. The real-coded genetic algorithm (GA) of the optimization method, employs the UNDX (Unimodal Normal Distribution Crossover) as a crossover operator, and employs the POSS (Pareto Optimal Selection Strategy) as a generation-alternation model. The hull form optimization for Series60 (CB=0.6) is carried out using the program that is based on the present method. In the optimization, many Pareto solutions are obtained. These hull forms have lower wave-making resistance with the panel-shift type Rankine source method on both the full load condition and the ballast condition, in comparison with the original hull form.