On the Hydrodynamics of Vertically Oscillating Planing Hulls

Abstract

This paper is concerned with the various modeling assumptions associated with planing boat dynamics and hydrodynamics when the hulls are traveling at low to moderate planing speeds. In particular, experimental results of the time-dependent behavior of the wetted length, amplitude dependence of the restoring force matrix, and amplitude and frequency dependence of the hydrodynamic inertia and damping matrices are presented. The experiments were conducted with prismatic hulls of varying speeds, length/beam ratios, and trim angles. Suggestions are made with respect to the physical modeling of the different terms in the equations of motion thus providing guidance to researchers interested in applying modern methods of dynamical systems analysis to planing dynamics. Significant nonlinear effects are identified in the restoring force matrix and relatively smaller ones in the added mass and damping matrices.