A system for transporting hydrocarbons in large water-depths from reserves located under the sea floor to a turret that is rotatably connected to a hydrocarbon production vessel that is floating at the sea surface, the hydrocarbons being transferred through substantially rigid catenary risers extending from the sea floor, said system for transporting hydrocarbons comprising: - three or more groups of mooring lines equally spaced apart, each group of mooring lines containing at least two individual mooring lines with polyester rope parts and which lower ends are attached to the seafloor with anchoring means; - said groups of mooring lines having open sectors there-between in which the substantially rigid catenary risers are located, the substantially rigid catenary risers and the grouped mooring lines are at the upper ends connected to and supported by one buoy that can be connected to and disconnected from the lower part of the turret, - the upper part of the buoy being provided with a fluid connector that is in fluid connection with the upper end of the substantially rigid catenary riser connector, for attachment to the fluid transfer system of the turret and to allow transfer of hydrocarbons from the seabed to the production vessel, the buoy being provided with buoyancy means ensuring that when disconnected from the turret, the buoy with attached substantially rigid risers and grouped mooring lines floats below the wave active zone in the upper half part of the water-depth, preferably in the upper quarter part, characterized in that an upper section of all the substantially rigid risers is directly attached to the buoy and provided with fairings, a middle section of each of the substantially rigid risers is provided with buoyancy modules so to give it a lazy wave shape, such that each substantially rigid catenary riser is a lazy wave riser, and a lower section of all the substantially rigid risers is in contact with the seafloor at a radial distance X from the buoy vertical axis that is smaller than the radial distance Y between the buoy vertical axis and the mooring lines anchoring means. - three or more groups of mooring lines equally spaced apart, each group of mooring lines containing at least two individual mooring lines with polyester rope parts and which lower ends are attached to the seafloor with anchoring means; - said groups of mooring lines having open sectors there-between in which the substantially rigid catenary risers are located, the substantially rigid catenary risers and the grouped mooring lines are at the upper ends connected to and supported by one buoy that can be connected to and disconnected from the lower part of the turret, - the upper part of the buoy being provided with a fluid connector that is in fluid connection with the upper end of the substantially rigid catenary riser connector, for attachment to the fluid transfer system of the turret and to allow transfer of hydrocarbons from the seabed to the production vessel, the buoy being provided with buoyancy means ensuring that when disconnected from the turret, the buoy with attached substantially rigid risers and grouped mooring lines floats below the wave active zone in the upper half part of the water-depth, preferably in the upper quarter part, characterized in that an upper section of all the substantially rigid risers is directly attached to the buoy and provided with fairings, a middle section of each of the substantially rigid risers is provided with buoyancy modules so to give it a lazy wave shape, such that each substantially rigid catenary riser is a lazy wave riser, and a lower section of all the substantially rigid risers is in contact with the seafloor at a radial distance X from the buoy vertical axis that is smaller than the radial distance Y between the buoy vertical axis and the mooring lines anchoring means. an upper section of all the substantially rigid risers is directly attached to the buoy and provided with fairings, a middle section of each of the substantially rigid risers is provided with buoyancy modules so to give it a lazy wave shape, such that each substantially rigid catenary riser is a lazy wave riser, and a lower section of all the substantially rigid risers is in contact with the seafloor at a radial distance X from the buoy vertical axis that is smaller than the radial distance Y between the buoy vertical axis and the mooring lines anchoring means.