Abstract: A dynamic control cable string or umbilical intended to hang in catenary form between a connection point on the seabed and a connection point located at the sea surface which can be attached to a floating structure; the umbilical is of the type that is low in weight per running meter and comprises flowlines and optionally current-conducting cables, all of which are twisted around the longitudinal axis of the string and are spaced apart from an axially extending core member and lie in channels in spacers for free axial movement of the cables and conduits in the channels; the core member, throughout the entire length of the control cable string functions as a load-bearing member and, in a portion of the length, all fluid transport and signal communication takes place peripherally relative to the core member.