Abstract: A sail batten suitable for roller-furling and composed of one or more long thin elements of a material possessing great stiffness and yield strength. The elements are formed so that their longitudinal cross-section is smoothly curved. Consequently this batten is stiff enough to provide the control of sail shape for which battens are used. Yet it is so resilient that, like a carpenter's rule, it flattens without damage into a flexible ribbon which coils tightly about a transverse axis. Thus a batten for sails which furl or reef about any axis. Chafe at an end is minimized by tapering the batten towards that end. Elements of compound curvature provide antisymmetrical stiffness to resist distortion of the sail to either side. Other species which achieve the same result are elements of opposing curvature nested in pockets together and elements of opposing curvature in substantially parallel pockets. Rigid connections between elements are only made at the end of the bundle which will be wound up first.