It is well known that migratory birds use an inverse V-shaped formation to reduce the energy consumption of following birds. In the same way, it is possible for a fleet of fishing vessels to minimize their total wave resistance, and thus save energy, by determining the most efficient formation. Although this is the same type of wave interaction problem faced by multihull ships, the fishing fleet has a large degree of freedom in the positioning of every vessel. In addition, it is expected to become a multi-modal problem, and the solution will require a global optimization technique. In this paper, we try to find the global optimal solution for this fleet formation problem using repulsive particle swarm optimization. Although it proved impossible to find the global optimum, we obtained two converged solutions with substantially fewer trials by separating the optimization process into two stages.