Drag reduction of hydrofoils for high-performance sailing: A review

Hydrofoil technology has transformed high-performance sailing by dramatically reducing wetted surface area and enabling vessel speeds that were previously unattainable for wind-powered craft. As hull-borne resistance is largely eliminated during foiling operation, hydrofoil drag becomes the dominant limitation to further performance gains. This review synthesizes findings from 136 peer-reviewed studies published between 2006 and 2026 and examines drag-reduction strategies spanning biomimetic surface modifications, cavitation management, free-surface interaction control, advanced materials and manufacturing, machine-learning-assisted optimization, air lubrication, and practical sailing applications. A unifying framework is proposed in which hydrofoil drag-reduction technologies are classified according to the dominant physical mechanisms they address: viscous drag, pressure drag, cavitation-related losses, and free-surface-induced drag. Reported drag reductions range from approximately 4%–8% for riblet surfaces and up to 80% for air-lubrication systems under favorable conditions, although performance varies substantially with Reynolds number, cavitation number, angle of attack, submergence depth, and implementation strategy. The review reveals a significant imbalance between computational investigations and full-scale validation, with most technologies remaining at intermediate stages of technological maturity despite promising laboratory-scale results. Key challenges include Reynolds-number scaling, turbulence–cavitation interactions, long-term durability, multiphysics coupling, and the lack of standardized validation methodologies. Overall, the literature indicates that future advances will depend less on isolated improvements within individual technologies and more on the integration of complementary drag-reduction mechanisms within adaptive hydrofoil systems capable of maintaining performance across diverse operating conditions.