Empirical model for bottom pressure of stepped planning monohulls

In this paper, an empirical based model for estimation of bottom pressure of stepped planning hulls is developed. This model is established by using previous empirical equations of pressure and wake of planning surfaces. Within the paper, equations for pressure distribution on fore and aft body are presented. These equations are derived based on sections parallel to stagnation line of planning craft. The step is assumed to act like transom, and its wake is predicted using previous equations develop for predicting the wake of transom. The final proposed model is able to predict pressure on both aft and fore body. The predicted results are compared against previous experimental data and it is observed that proposed method has good accuracy. Parametric studies are carried out and it is seen that if the height of step is increased, pressure of aft body increases. In addition to this, it is observed that the ratio of step height over keel has an inverse relation with pressure of aft body.