The present invention relates to a damper for damping the reactionary motion of a wave energy conversion device to wave motion, comprising a damping energy absorber (7) having a reversible non-linear stress-strain response, arranged to damp the reactionary motion of the WEC. According to a first aspect, there is provided a damping structure (2) for a wave energy conversion device (1). The structure comprises a fixed member (6), and a damping member (7) having a reversible non-linear stress-strain response. The present invention also relates to a mooring component (2) for a mooring system (1) and to a method for manufacturing a mooring component (2). The component comprises a deformable element (6) having a reversible non-linear stress-strain response, wherein the response is a composite reversible non-linear stress-strain response.