Prediction of planing hull side forces in yaw using slender body oblique impact theory

• Oblique two-dimensional wedge impact theory is applied to three dimensional planning.
• Planing hull side forces are estimated using a zero gravity 2D method.
• Experiments are conducted to measure side forces on planing craft.
• Existing and new experimental data are compared with the present prediction method.
• Suggestions are made to extend the range of applicability.

Recent advances in the slender body theory and computational methods have enabled the study of asymmetric and oblique impacts of wedges on a flat free surface. These two-dimensional oblique impact predictions are often used for studies of wave slam loadings, as well as observations of the asymmetric formation of the spray jets. In the present study, an existing zero gravity, inviscid two-dimensional oblique impact model is applied to the three-dimensional planing case using slender body theory, producing estimates of planing hull side force as a function of yaw angle. Plots are generated to predict the side force generated by planing surfaces as a function of speed, beam, wetted length, trim angle and yaw angle. The resulting predictions are compared with previously published and new measurements of planing hull side forces during steady drift tests. The comparisons are used to establish recommended limitations of the method and provide insight into future work.