Hydrodynamic impact loads on 30 degree and 60 degree V-step plan-form models with and without dead rise

Philip M. Edge, Jean P. Mason
SEP 1958

Hydrodynamic impact loads of 30 and 60 degrees included angle V-step models were investigated at the Langley impact basin. The investigation consisted of a series of fixed-trim impacts in smooth water with a dead-rise model having a round keel and chine flare and a beam-loading coefficient of 3.5. Impact loads and motions for a range of trim and flight-path angles were measured to determine effects of step plan-form angle and for comparison with data for a flat-bottom model. The data are presented in a table, and typical time histories and variations of maximum impact lift and maximum draft with trim and flight-path angle are included. Over the range of the tests the maximum loads for the 30-degree V-step model are shown to be as much as 29 percent less than those for the 60 -degree V-step model. Effects of dead rise for the 30-degree V-step model are shown to indicate that this configuration experiences loads as small as 50 percent of those experienced by a similar V-step flat-bottom model.

An Adobe Acrobat (PDF) file of the entire report: