Comparative study of experimental and CFD results for stepped planing hulls

In recent years, research has been conducted on reducing resistance by adding steps on the bottom of high-speed craft. The most significant issue in the design of multi-stepped planing craft is the selection of an appropriate step configuration, i.e., step geometry, location, and height. This requires a general knowledge of the hydrodynamic behavior of each step configuration. Although the towing tank test is an effective method to predict accurately the hydrodynamic behavior of stepped planing boats, there are restrictions in studying some details. In this study, a Computational Fluid Dynamic (CFD) method is used to investigate the hydrodynamic behavior of a stepped planing hull with eight different step configurations in detail. Comparison of the results of trim angle, resistance, sinkage, wetted surface, and ventilation length of swept-stepped planing hulls for different step configurations at various Froude numbers shows that a maximum average resistance reduction occurs at 1.9 < FrB < 4.0 with the step height of 2.73% BTC located at 48.46% L from the transom. There is also a lower resistance associated with a step height of 0.91% BTC at 48.35% L distance from the transom at FrB > 4. These results can be used to improve high-speed planing hull performances by utilizing an appropriate step configuration.