Fourthly, This paper choose RFR for main index, and speed and deadweight isoptimized index.This paper applied evolutionary algorithms optimize the ship shape.

• (4)从我国粮食运输系统的整体出发，以必要运费率为主要评价指标，航速和载重吨为优化参数，运用遗传算法对该运输系统的单航线船型进行优化。