force from the deck through the bracket to the rib and into the riser such that the tensioners on the riser are not subjected to torque application_number US 27060308 A description referring to fig1 riser tensioner assembly 11 provides tension to a riser 13 that has its lower end secured to subsea equipment such as a subsea wellhead assembly not shown riser 13 extends upward through an opening 15 in a deck 17 of the vessel although moored typically the vessel will move relative to riser 13 in response to current and wave motion a plurality of cylinder assemblies 19 are supplied with hydraulic fluid and gas under pressure to provide an upward force to riser 13 to maintain a uniform tension in riser 13 as deck 17 moves relative to riser 13 cylinder assemblies 19 are conventional each having a piston and piston rod a lower end of each cylinder assembly 19 is mounted to deck 17 and an upper end is mounted to a clamp assembly 21 which clamps to riser 13 a plurality of guide rollers 23 may be employed to centralize riser 13 guide rollers 23 are mounted circumferentially around riser 13 for rolling engagement with riser 13 or a component mounted to riser 13 in this embodiment a cylindrical sleeve 25 is mounted around riser 13.