Abstract: Connecting means for connecting the ends of at least a pair of pipes, said pipe ends being immersed in water and one of the or each pair of pipe ends being mounted on a fixed structure and connected, e.g. to an oil well, and the other of the or each pair of pipes being mounted on a movable structure, e.g. a column, mounted for oscillatory movement relative to the fixed structure, comprises in respect of the or each pair of pipes a tube of a length greater than the maximum distance between the pipe ends and in a spiral and/or helical shape, wherein the tube is supported intermediate the ends thereof solely by means for correcting the buoyancy thereof to reduce the buoyancy to substantially zero.