Abstract: A hydraulic tensioning device for tensioning the rigging of a sailing vessel comprises first, second and third components which are telescopical with respect to one another. A cylinder of the first component and a piston of the second component form a first chamber, and a cylinder of the second component and a piston of the third component form a second chamber, the two chambers being in fluid flow communication with one another via a passage. The first component is connected to one part of the rigging, and the second component to another part of the rigging. The rigging is tensioned by applying tension to a rope or wire connected to the third component. In another embodiment the first component is mounted for guided displacement along a rail, the second and third components each being connected by a rope or wire to a cam cleat to limit longitudinal displacement.