Disclosed is a method and apparatus for maintaining fluid low between a subsea wellhead riser conduit 10, 12, 14 and a weathervaning floating production, storage and off-loading [FPSO) vessel without swivel or sliding seals. The riser conduit 10, 1 2, 14 is divided into first and second flowpaths A, B which terminate in connectors 22, 2 4 . First and second drums 34, 36, coaxially mounted for rotation about a vertical axis, have connectors 26, 28 which are connectable with the flowpath connectors 22, 2 4 . The drum connectors 26, 28 are connected to one end of flexible pipes, 41, 41, 43, 50, 51, 52, at least partially wound around a respective drum, with the other end tensioned and connected fixably to the FPSO vessel. Enough flexible pipe is on each drum 34, 36 to permit the drum to rotate about a connection arc of greater than 180° when its respective connector 26, 28 connects one flowpath with the FPSO vessel. The connectors and drums are disposed such that each connection arc overlaps the other arc at both ends of each arc. Fluid flow is maintained through the first flowpath A until the weathervaning vessel approaches the end of the connection arc of the first drum, 34. After the overlap region is reached flow is established in the second flowpath B through the second drum 36 and flowpath connector 24. When the end of the connection arc of the first drum 34 is reached, the first flowpath connector 22 is disconnected thereby terminating fluid flow in the first flowpath A while fluid flow is maintained in the second flowpath B. Should further weathervaning continue such that the first drum connection arc is again reached, reconnection of the first drum 34 and flowpath A occurs.