Abstract: A method of positioning a pipeline across a water-course. A first coffer dam is formed to isolate a first area of the water-course and a first part of the pipeline is then positioned in the first area. A chamber is put at the distal end of the first part of the pipeline. The chamber has an upper portion with an open top and a lower portion as opposed ports to receive the pipeline. The first coffer dam is then dismantled. A second coffer dam is formed to isolate a second area of the water-course. The second area includes the chamber. The first and second areas of the water-course are positioned to include the path of the pipeline across the water-course. A second part of the pipeline is located in the chamber and a aligned with the first part of the pipeline. The ports are sealed around the pipeline. Water is removed from the chamber to allow make-up of the pipeline by joining of the first and second parts within the chamber. The upper portion of the chamber is removed and the second coffer dam is dismantled.