Abstract
Ultra large ships have the advantage of scale economies, but whether they successfully getting into service depend on cargo flow, shipping distance, port efficiency and constraints, etc. The study constructs a two-objective model to determine the optimal ship size and sailings frequency and analyze the shipping economies of ultra large ships by minimizing shipping costs and inventory costs. The results show the Pareto optimal solutions of the two-objective model and optimal ship size and sailings frequency with respect to each level of inventory costs and shipping costs. The sensitivity analysis shows the optimal ship tends to be large as route flow increases. Furthermore, the economies and possibility of using ultra large ships tend to increase, as port efficiency improves, shipping distance increases, the ports of call decreases, or the relative costs of large ships decrease.
