Abstract: A mobile offshore drilling unit includes a hull member having an opening of predetermined size for receiving a separately fabricated, interchangeable, rig block, which further includes a draw works, a drilling floor, a diesel driver, an electric generator, a derrick, and at least one each of a mud pump, mud tank, a fuel tank, and a drilling water tank. The method of constructing such a unit includes constructing the hull member at a marine shipyard and fabricating the interchangeable rig block at a remote location. The rig block is constructed with the main deck having a drilling floor and mounting a draw works thereon; constructing a machinery deck with a diesel driver, an electric generator, and at least one mud pump; and constructing a tank deck with at least one each of a fuel tank and a water tank.

Abstract: A submersible/semi-submersible dry lift carrier for transporting a jack-up drilling rig in a body of water includes a hull, a deck, at least one stability column, and a plurality of ballast compartments capable of being flooded and emptied for lowering and raising the carrier. The carrier further includes at least three leg wells, each well sized and spaced for receiving a leg from a jack-up drilling rig, and each of said wells comprising a vertical passageway having a first end opening through the deck and a second end opening through the bottom of the hull. The carrier further includes at least three pinning receptacles, each receptacle sized and spaced for receiving a spud can and leg from a jack-up drilling rig. In operation, the dry lift carrier is partially submerged by flooding the ballast compartments and then positioned beneath the floating jack-up rig. The carrier is de-ballasted thereby lifting the jack-up rig from a floating "wet" mode to a "dry" mode on the deck of the carrier.