The difficulty experienced by researchers while designing marine current turbine rotors is designing a superior-performance and cavitation free hydrofoil. The design of a high performance and cavitation free hydrofoil HF-Sx is presented in the present paper. Both numerical and experimental studies are carried out on the section. This hydrofoil can be used as the section of the outboard region of a horizontal axis 10 m rotor operating at a tip speed ratio of 4.3, determined using Blade element momentum theory. The section characteristics of HF-Sx as a blade section for 10 m are presented and its characteristics are compared with other hydrofoils used in marine current turbines. (C) 2011 Elsevier Ltd. All rights reserved.