An apparatus for supporting a structure on a platform. The platform may be a floating platform. The apparatus comprises a base frame, wherein the base frame has a first bracket and a second bracket attached thereto. The apparatus further includes a x-axis frame having a first pivot point and a second pivot point. The apparatus further comprises a z-axis frame having a third pivot point and a fourth pivot point. A sliding frame assembly is operatively positioned within the z-axis frame, and wherein the sliding frame assembly has a plurality of rods for connecting with an injector head. The apparatus may further include a motion restriction system that restricts movement of the x-axis frame and the z-axis frame. The sliding frame assembly comprises a sliding pad for lateral movement. A method for compensating for the movement of a floating platform having a riser extending therefrom is also disclosed.