Patent ID: 6857822

Claim:
A riser system for transporting fluid cargo from a sub sea facility to a vessel in a body of water comprising: a flexible riser for transporting fluid cargo from a sub sea facility to a vessel; and a riser tensioning mechanism comprising: a riser tensioning element having a first end and a second end; a submerged base; a pivot connection attached to said base and to said first end of said tensioning element for allowing said tensioning element to pivot about said base; means for securing said riser to said second end of said tensioning element; and means for applying tension to said riser that urges said tensioning element toward an equilibrium position; whereby, movement of said riser causes said riser tensioning element to move away from said equilibrium position and causes said means for applying tension to apply a counteracting force that urges said tensioning element back toward said equilibrium position, thereby maintaining tension on said riser, wherein said means for applying tension comprises one or more tension applying elements disposed on said tensioning element, said tension applying elements selected from the group comprising a buoy and a weight, wherein a buoy is disposed at said second end of said tensioning element and said riser is attached to said buoy, wherein said buoy has a curved outer surface and said riser is attached to said curved outer surface, wherein said system further includes a rigid section of pipe attached to said curved outer surface of said buoy and having a first end for attachment to a sub sea flow line and a second end attached to a first end of said flexible riser.