The invention is a rigid supporting member that changes position within a pocket of sheet material to accommodate a deployed position and a stowed position, as may be used, for example, with battens in roller furling sails. The member is placed within the pocket formed within sheets of a pliable material, or attached to the pliable material, and the member is movably secured within the pocket, such as with a pivoting fixture. The member may be rotated into a first position that supports a shape of the pliable material when the pliable material is deployed, and a second position that accommodates stowage of the pliable material through folding, rolling, or the like. A variety of control systems may be used to control rotation or other movement of the member, and to control deployment and stowage of the pliable material.