RISER BUOYANCY ADJUSTABLE THRUST COLUMN

An offshore drilling riser joint has a central riser pipe, a number of auxiliary lines mounted around it, and a buoyancy module assembly of a buoyant material. A pair of upper thrust sleeves slide over two of the auxiliary lines, each of the upper thrust sleeves having a flange in contact with an upper end of the buoyancy module assembly. Each of the upper thrust sleeves transfer upward thrust imposed by the buoyancy module assembly to an upper support flange mounted to the central riser pipe. A pair of lower thrust sleeves slide over two of the auxiliary lines. Each lower thrust sleeve has a lower thrust flange that is engaged by a lower end of the buoyancy module assembly. Each of the lower thrust sleeves transfer weight of the buoyancy module assembly while out of water to a lower support flange mounted to the central riser pipe.