The Raked-Wedge Hull: A Severe Test of Linear Wave-Making Theory

The idealized raked-wedge hull has a triangular waterplane with its base of finite beam at the transom stern and its apex of zero beam at the stem of the bow. The sections are rectangular and the draft increases linearly from zero at the stern to the maximum draft at the bow. This hullform provides a challenge for the traditional linear wave-making theory. Nevertheless, there is good agreement between the theory and the towing-tank data for the total resistance, provided that a reasonable value of the frictional form factor of 1.24 is chosen. It is also demonstrated that almost identical predictions are provided by simpler equivalent hulls — including distributions of line sources — which possess the same prismatic coefficient and the same local vertical centroid of the section area. Lastly, the calculations indicate that this new hull has a wave resistance which exceeds that of traditional vessels by generally more than 30%.