Riser guide and support mechanism

A riser guide and support mechanism for a floating vessel, and particularly a spar type structure, where the buoyancy can stem extends nearly the entire length of the floating vessel. A riser centralizing element is provided on the riser near the lower end of the buoyancy guide stem. Riser bend limiting elements are positioned on the riser so as to extend above and below the riser centralizing element. Since the buoyancy cans and buoyancy can stem are not required to rotate relative to the stem guides on the floating vessel, the stem guides can be formed from pipe sections that provide a much larger bearing area than is customary.