Abstract: A method and apparatus for preventing contact between a pipeline and a seafloor while running and/or storing the pipeline between an onshore site and a marine location, the apparatus comprising buoyancy means positionable between said onshore site and said marine location, the buoyancy means being cooperable with the pipeline.

Abstract: A hybrid riser having a lower section (6) and an upper section (10), said upper section comprising a flexible pipe, and said lower section comprising a substantially rigid pipe in communication with the flexible pipe, said riser further comprising a buoyancy section (16) at or in the region of an upper end of said rigid pipe (13). Said buoyancy section (16) also comprises an elongate cylindrical buoyancy element, which may be of a coaxial compartmentalised tubular construction having valves such that it may be controllably flooded or evacuated. The hybrid riser may be tethered to a surface vessel or to the seabed. The hybrid riser may be constructed on land, and towed to the vicinity of the installation to which it is to be connected.