Abstract: A single-point mooring system is provided for substantially permanently mooring a floating structure, such as an offshore natural gas treatment facility located on a shipform hull, to an anchor point. A rigid anchor structure, fixed to the bottom of the water body, defines a vertically oriented circular cylinder above the water surface. A collar is mounted circumferentially of the cylinder for movement about and along the cylinder. A pair of rigid arms extend from the floating structure in spaced relation to either side of the cylinder and are spaced equally from the roll axis of the floating structure.