Light weight transfer referencing and mooring system

An offshore fluid transfer system is described for transferring fluid between an underwater pipe 12 and a dynamically positioned vessel 16 at the sea surface, which is relatively lightweight and economical. The system includes a riser 24 having an upper end attached to the vessel and a lower end having a chain table 36 held by chains 40 extending in catenary curves to the sea floor and weighted by a weight 44 hanging by the chain table. The riser supplies substantially the only mooring force most of the time, while thruster equipment 30 on the vessel supplies sufficient additional force a small amount of the time to limit vessel drift in violent storms. The upper several meters of the riser is a rigid pipe 50, and an instrument that measures tilt of the pipe indicates the amount and direction of drift of the vessel. <IMAGE>