A turret mooring system for a vessel which includes a moon pool comprises a turret which is positioned in the moon pool, a buoy and anchor chain assembly for anchoring the turret to the sea floor, a bearing assembly for rotatably connecting the turret to the vessel, and a bearing support assembly which comprises an upper ring member to which the bearing assembly is connected, a lower ring member which is connected to the vessel in the moon pool, and a number of elongated support beams which are connected between the upper and lower ring members. In addition, the lower ring member is connected to the vessel near the vertical center of the vessel in order to minimize the deflections of the bearing assembly due to hogging and sagging of the vessel.