An empirical analysis of the planing lift characteristics of rectangular flat-plates and wedges

Abstract

The fluid flow about planing plates and wedges is briefly described and discussed, and on the basis of theoretical and physical considerations of this flow empirical formulae are presented for the lift developed by these planing surfaces. The formulae are mutually compatible and cover the whole range of planing of zero and finite deadrise surfaces including the chine-dry and chine-wet conditions. The lift formulae are extensively compared with experimental data, over a range of trim angles from 2 to 30 deg and deadrise angles from 0 to 40 deg, and very good agreement obtained. The analysis confirms the existence of an effective critical wetted length for all the planing surfaces studied and shows that the wave-rise about planing wedges is an irrelevant feature of the flow. The formulae are thought to be of such a nature that they may form the foundation for the lift prediction of more complex planing surfaces than are dealt with here.