Remotely controlled chain and wire stoppers used onboard AHTS to unshackle lengths of wire on deck when carrying a loaded wire over the stern roller. It comprises a hydraulically-operated cylindrical unit which can be retracted flush with the working deck for stowage or raised to a working position. In the working position, the wire or chain is supported clear of the deck. The cylindrical unit is forked at the top and contains a pair of hydraulically-operated jaws. Two sets of jaws can be interchanged quickly; one for wire, the other for chain. The wire slides between the open jaws, the jaws are closed and the winch eases off the strain allowing the splice on the wire to be pulled against the jaws, thus enabling the buoy to be safely unshackled.