Resistance Analysis of a Hydrofoil Supported Watercraft (Hysuwac): A Case Study

Energy efficiency and environmental sustainability are important aspects in ship design and operation. Hull-shape optimization, hull cleaning and coating, and the use of appendages are, among others, well-known efforts to reduce ship fuel consumption. Regarding energy efficiency and environmental sustainability, it is possible to effectively reduce the resistance of an existing catamaran by retrofitting a foil system to it. In this study, a foil system is designed and retrofitted to a catamaran to reduce its total resistance. Reynolds-averaged Navier-Stokes simulations, utilizing k-w SST turbulence model, were performed to study the effects of the foil system on the vessel’s total resistance. Free surface effects were modelled, i.e., the generation of waves due to the vessel’s movement on the water surface. The foil system affects the wetted surface area, running sinkage and trim, and the wave pattern generated by the vessel, which ultimately affect the vessel’s total resistance. At relatively low speeds (Fr < 0.7), an increase of the total resistance, reaching a value of approximately 11%, was observed due to the foil system. However, at higher speeds (Fr > 0.7), the foil system decreases the total resistance, reaching a value of approximately 32% at the service speed (Fr = 1.24). The 32% resistance reduction at the service speed is promising in view of the intended purpose of the foil system as an energy saving device.