A mooring system comprising a submerged buoy releasably connectable to a vessel keel having a combined axial/radial bearing. A segmented ring, fastened to the buoy, forms the bearing outer ring. An inner bearing hub slidingly carried on the bearing outer ring is connectable to a vessel structural connector. In a first embodiment, the structural connector includes an inner cylindrical sleeve coaxially movable within an outer cylindrical housing by circumferential actuators. The lower ends of the connector sleeve and connector housing capture plural collet segments circumpositioned therebetween that radially move in and out as the connector sleeve is moved axially within the connector housing. The lower ends of the collet segments extend downward into the bearing hub and releasably engage an interior groove therein, thereby dogging the bearing hub against the vessel. In a second embodiment, the bearing hub is simply bolted directly to a cylindrical connector member of the vessel.