Study of Prismatic Planing Model Spray and Resistance Components

Abstract

The results of a study of prismatic planing model spray and resistance components are presented. The calculated total resistance values are shown to be in good agreement with the measured resistance. The features of the whisker spray and spray blister are discussed along with an experimental technique using wide-beam prismatic models for measuring the spray thickness. A derivation based on energy considerations of the prismatic planing hull pressure resistance component and the spray thickness is presented. The spray thickness values calculated from this formulation are in qualitative agreement with the measured spray thickness. The frictional resistance component obtained from the resistance measurements indicated an extensive laminar flow on the planing model bottom. An acetanilid film was sprayed on the planing model bottom which tripped the laminar-turbulent transition. The CF-values estimated from the acetanilid film pattern were found to be 75 to 90 percent of the CF-values estimated from the corresponding resistance tests.