OPTIMISATION OF A MULTI-PURPOSE CARGO SHIP FROM THE HYDRODYNAMIC AND PROPULSIVE VIEWPOINT

An account is given of model tests carried out, on behalf of Empresa Nacional Bazan, at the El Pardo tank to investigate the optimisation of a design for a 15,000-dwt multi-purpose cargo ship. The study programme consisted of: the establishment of a basic hull-design, and the design of a bulbous bow for it; the selection of a stock propeller and the design of two new propellers (all controllable-pitch); the design of three stern-frame and rudder configurations to suit the three propellers; and systematic model tests, including towed and self-propulsion tests, open-water tests on the propellers, and wake surveys. The tests showed that the bulbous bow increased speed by an average of about 0.24 to 0.85 knots, according to loading condition. Neither of the two alternative propellers showed a clear propulsive advantage over the other, and selection should therefore be based on cavitation considerations. It was also concluded, from the wake surveys, that the effects of stern form on the flow predominate over those of the bulbous bow. Some further conclusions are drawn. Order from: BSRA as No. 46,879.