(EN) An ocean riser assembly (30) for con- veying fluids between the seabed and the sur- face of the sea includes a fluid conveying pipe (31) formed into a helical configuration or into a planar cyclically undulating configu- ration, such as a sinusoid, that extends lon- gitudinally from the bottom of the sea to the surface. One or more flexible and preferably elastic tension members (38) extend in the longitudinal direction of the riser assembly and are secured to the pipe at spaced intervals, so that they absorb tension forces applied be- tween the ends of the riser assembly (30). The helical or undulating configuration of the riser pipe decouples axial stresses in the pipe (31) caused by internal fluid pressure from stresses caused by external tension forces act- ing on the riser assembly (30), the external tension forces being converted to torque and bending moments acting on the pipe itself.
