Velocity Prediction Program for a Hydrofoiling Lake Racer

The aim of this paper is to develop an accurate and robust six degrees of freedom stationary velocity prediction program (VPP) applied to a high-performance sailing yacht. The model is set up to assist NC Raceboats with the VPP based hydrofoil design, considering the sailing performance in three modes: displacement, transition and hydrofoil. The yacht is a lightweight monohull designed for light wind conditions with up to five crew members. The design includes a self-stabilizing hydrofoil configuration and an elevator rudder. The software tool, which is used for the velocity prediction program, is FS-Equilibrium, developed by DNV. The software offers a modular workbench in which each force can be modelled with semi-empirical force modules, which are based on validated methods and theories. The performance prediction is interpreted and discussed: as foreseen, the performance of the high-performance lake racer in hydrofoiling condition is significantly improved compared to its assessment in displacement sailing mode. In medium breeze conditions, the yacht is able to lift up on its hydrofoils and attain flight mode. The minimum hydrofoiling speed investigation demonstrates that the VPP is able to consistently iterate Through the transition mode. This paper shows that it is possible to develop a VPP model for a hydrofoiling sailing yacht on the basis of relatively simple assumptions and theories.