Reduced-Order, 6-DOF Model for Hydrofoil Boat Dynamics

The application of hydrofoil systems can improve efficiency and increase speed of fast boats. Thanks to advances in fabrication of strong and light materials, as well as cost reduction of electronic control systems, hydrofoils are currently reintroduced to the market of advanced marine vehicles. As hydrodynamics of hydrofoils near the free water surface and in unsteady regimes is quite complex, reduced-order modeling for hydrofoil boat dynamics can help accelerate design and optimization of high-performance hydrofoil systems. This paper describes a 6-DOF dynamics model that can be applied for simulating steady and unsteady motions of hydrofoil boats in foilborne regimes. The equations used for hydrodynamic forces on hydrofoils originate from semi-empirical engineering correlations and account for the most important unsteady effects. Representative results are shown in this paper for a hydrofoil boat operating in steady states, performing a turning circle maneuver, and maintaining course in the presence of bow and quartering waves. The developed model can benefit engineers designing hydrofoil systems for marine craft.