Riser tensioning system

摘要

A tensioner (10) is disclosed for use in tensioning connecting lines (16) connecting a marine riser (14) to a floating platform (12). The tensioner (10) is a passive system which incorporates a series of cylindrical elastomeric members (42, 54, 60) which are deformed in torsion to exert the proper tension on the connecting line (16). A specially tapered drum (30) is provided on the tensioner so that the radial distance from the axis of rotation of the drum to the position where the line leaves the drum varies to compensate for the variation in torsional moment of the elastomeric members so that a predetermined tension can be maintained on the line (16) as the line is payed out and taken in from the tapered drum.