Abstract: A method for installing or removing a tension-leg platform with at least three tendon porches, and its tendons, the method includes grasping each of three or more extended tendons by a respective one jacking tool on one tendon porch, wherein the platform is being stabilized by at least three jacking tools each applying tension on the respective extended tendon. Extended tendons are created by connecting one or more tendon extension piece end-to-end from a tendon.