Hydrodynamic optimisation of a multi-purpose wind offshore supply vessel

The aim of this study was to reduce the total resistance of a multi-purpose wind offshore supply vessel by optimising its hull. Resistance was computed using a potential flow boundary element method and a Reynolds-averaged Navier-Stokes equations solver. Optimised hull forms were obtained for the ship advancing at different ship speeds under calm water conditions, employing the two multi-objective optimisation algorithms, Non-dominated Sorting Genetic Algorithm II (NSGA-II) and Multi-Objective Simulated Annealing (MOSA). Using NSGA-II yielded slightly larger reductions of total resistances than MOSA. The greatest reductions were achieved at ship speeds between 11 and 14knots. At these speeds, a thinner and longer bulbous bow reduced resistance. At speeds greater than 15knots, a bloated bulbous bow was more helpful to reduce resistance.