A simplified method for the evaluation of the total resistance of a foiling yacht in upright condition

TL;DR

This paper introduces a simplified model and CFD simulations to evaluate the total resistance of foiling yachts in upright conditions, highlighting the impact of foils on speed and resistance reduction.

Contribution

It presents a schematic force model combined with CFD analysis to assess foil effects on yacht resistance, offering a new approach for performance evaluation.

Findings

Foils can reduce total resistance at certain speeds.

CFD simulations provide detailed resistance and lift coefficients.

The model identifies speed regimes with resistance advantages.

Abstract

An extremely schematic model of the forces acting an a sailing yacht equipped with a system of foils is here presented and discussed. The role of the foils is to raise the hull from the water in order to reduce the total resistance and then increase the speed. Some CFD simulations are providing the total resistance of the bare hull at some values of speed and displacement, as well as the characteristics (drag and lift coefficients) of the 2D foil sections used for the appendages. A parametric study has been performed for the characterization of a foil of finite dimensions. The equilibrium of the vertical forces and longitudinal moments, as well as a reduced displacement, is obtained by controlling the pitch angle of the foils. The value of the total resistance of the yacht with foils is then compared with the case without foils, evidencing the speed regime where an advantage is obtained, if any.