Abstract: A device for coupling a barge unit to a pusher-tug for sea transport, comprising guiding rollers mounted on the barge on a line perpendicular to the plane of symmetry of the pusher-tug. Two coupling cables pass on the rollers and the cables are connected at one end to shock absorbers at the stern portion of the tug and at opposite ends to hydraulic power devices at the bow portion of the tug. The cable has an inclination angle .alpha..sub.1 with respect to the symmetry plane of the tug at the connection with the shock absorber and an inclination angle .alpha..sub.2 at the connection with the hydraulic power devices. The angles are selected such that for a preload in the cable equal to force P developed by the hydraulic power devices, the difference between P cos.alpha..sub.1 and P cos.alpha..sub.2 is at least equal to one-half of the force tending to separate the tug and the barge.