A recreational watercraft device consisting of a light hull in the shape of a sail board hull and on the bottom a strut hydrofoil assembly. The hydrofoil has a bilateral symmetric plan-form with a pivot connection at the center of the hydrofoil span. The pivot connection joins the hydrofoil to the strut. The strut has a streamline cross-section. The plane of symmetry of the strut is positioned in the plane of symmetry perpendicular to the span of the hydrofoil. In operation the rider stands on the hull and reciprocates the hydrofoil up and down via a strut having a T handle. The elements of the strut hydrofoil assembly comprise a foil, a pivot, a strut, a T handle, and extension.