Abstract: A carrier for cargo or personnel is transferred between an offshore platform and a landing platform on a vessel while subject, one with respect to the other, to vertical and lateral movements due to waves and wind within an envelope of motion. When the carrier is on the offshore platform, it is lowered by a cable from a constant tension level lifting winch to a point above the envelope of motion by the landing platform on a vessel. A trailing end of this cable is coupled to the cable of a downhaul winch having variable constant tension levels on the vessel. Slack is eliminated in the coupled cables and the carrier is caused to rise and fall with the movement of the vessel through a preestablished constant tension level by the lifting winch. Constant tension is developed in the coupled cables when the vessel moves toward the carrier within the envelope of motion while the downhaul winch is set at a higher tension level and zero winding speed.