Hydrofoils: Optimum Lift-Off Speed for Sailboats

See allHide authors and affiliations

Science  13 Dec 1968:
Vol. 162, Issue 3859, pp. 1273-1275
DOI: 10.1126/science.162.3859.1273


For a hydrofoil sailboat there is a unique optimum lift-off speed. Before this speed is reached, if there are no parasitic vertical hydrofoil appendages, the submerged or partially submerged hydrofoils increase drag and degrade performance. As soon as this speed is reached and the hydrofoils are fully and promptly deployed, the performance of a hydrofoil-borne craft is significantly improved. At speeds exceeding optimum lift-off speed, partially submerged hydrofoils impair performance if there is no significant effect of loading on the hydrofoil lift-to-drag ratio.

Stay Connected to Science