A Matrix Data Base Approach to Planing Craft Resistance Model Experiments

A matrix data base approach to the modeling of planing craft thrustline in towing tank resistance experiments is presented. The matrix data base approach does not actually attempt to model a specific thrustline geometry in the towing tank. Instead, a matrix of drag and running trims for a discrete range of model weights on water and longitudinal centers of gravity are obtained experimentally with a model fixed in surge, and free in pitch and heave. This matrix is then curve fit and the desired thrustline conditions are either interpolated or extrapolated from the experimentally derived data base. This method provides not only the performance information for the desired ballast and thrustline condition, but also the ability to estimate performance over a fairly large range of gross vehicle weights, longitudinal centers of gravity, and thrustline geometries.