When coils of metal are lifted, the crane hook alone weighs 20 tons. If it accelerates too quickly or brakes too abruptly, the hook swings for hours and can injure people, cause damage and slow down processes. With extensive engineering experience, simple means and the smallest INSEVIS panel PLC, the Korean company EREFA Co. Ltd. has succeeded in developing an anti-sway system and is already using it in series production at large shipyards.