Abstract: A leg mating system for aligning a pre-constructed deck portion with a previously situated base portion of an offshore platform. The deck portion is supported upon a barge and brought into position above the base. A plurality of stabbing pins are hydraulically extended from the legs of the deck portion and are received in capture members in the legs of the base portion. A first spring having a first spring rate and a second spring having a second spring rate higher than the first, are operative in that order to resiliently oppose reduction of the separation between the deck and base portions with a spring rate which increases as the separation decreases. The capture members are capable of accommodating axial misalignment between the legs of the deck and base portions of up to five degrees.