An apparatus and method for maintaining electrical and hydraulic connections between a junction box (or junction boxes) located on or near an offshore platform's floor and a movable drilling rig structure are disclosed. The disclosed invention is a unique vertically folding service arm capable of moving in both the horizontal and vertical directions in order to provide enhanced range of movement. The increased range of movement provided by the vertically folding service arm of the present invention allows electrical and hydraulic supply lines to remain connected between a junction box (or boxes) located on or near the platform floor and the rig structure even as the rig structure moves back-and-forth on the platform between multiple well centers. The vertically folding service arm of the present invention can also be easily disconnected and "folded" for transport without requiring the electrical and hydraulic supply lines to be disconnected from the drilling rig structure.