Making a Splash: Experimentally Modeling a Single Slamming Event of Planing Craft

Ben Darden, Christine Gilbert

Abstract

Slamming into waves can cause structural damage to high-speed planing craft, as well as hinder or injure onboard personnel. As such, it is one of the main limiting constraints of high-speed surface vessels' operating envelopes. The controlled motion experiments presented in this talk allow for the capture of a single slam event, allowing for a deeper study of the effects of hydrodynamic loads occurring in a slam. A planing hull model, attached to a moving carriage, was subjected to controlled vertical motions using two linear actuators to resemble real-life slamming motions but in a rotated frame of reference. The system allows for the trim angle of the model to be adjusted. Hydrodynamic forces are measured globally and pressures were measured at locations near the bow. With this configuration, the maximum forces and peak pressures experienced by the model increased when slammed at higher total velocities relative to the free surface. However, slams into the water at steeper impact angles resulted in a decrease in forces and pressures. Experiments fixed the body orientation during the slam event. The results from this study can aid in new tools that can be used to evaluate slamming for the design of small craft. *Funding from ONR Grant #N00014-20-1-2254 is gratefully acknowledged.