A riser is connected to subsea well equipment and extends to a vessel. A tubular conductor is mounted stationarily to and around the riser, the conductor passing through an opening in the vessel. A set of rollers is mounted to the vessel around the opening for engagement with the conductor as the vessel moves relative to the riser. Hydro-pneumatic cylinder units are connected between the riser and the vessel for applying tension to the riser. An external flange is located on a lower portion of the conductor. A shock absorber is positioned around the conductor and mounted to the vessel for movement relative to the conductor. The shock absorber absorbs shock when the cylinder units are in an extreme stroke position.