Abstract: A submersible offshore jack-up frame comprises a base and at least four legs, wherein said base is positionable along said legs, so that said base may be moved from a first position wherein said base is transportable on the deck of a surface vessel such as a barge, to a second position wherein said base is above a water surface when supported by said legs. The base may be elevated above the deck of the barge when supported by said legs. The base is also positionable on said legs so as to be submerged below the water surface to allow a barge to be positioned above the base, and then elevated to support the barge above sea level.