Abstract: A vessel is provided that is an improvement over previously disclosed jack-up rigs and lift boats. The vessel has at least three thrusters and is self-propelled. The vessel additionally has a raised and hollow crane support on which a crane may be mounted. The crane support is affixed to tracks, which permit the crane to slide along the deck of the vessel. The raised and hollowed feature of the crane support permits the storage of equipment and things beneath the crane support without hindering the movement of the crane along the tracks. Optionally, the vessel further comprises a sub-base structure removably affixed to the transom of the vessel; a base structure removably affixed to the sub-base structure; and a work-over rig removably affixed to the base structure. Also provided herein are methods of using the crane and affixing the sub-base structure, base structure, and work-over rig to the vessel's transom.

Abstract: A vessel is provided that is an improvement over previously disclosed jack-up rigs and lift boats. The vessel has at least three thrusters and is self-propelled. The vessel additionally has a raised and hollow crane support on which a crane may be mounted. The crane support is preferably affixed to tracks, which permit the crane to slide along the deck of the vessel. The raised and hollowed feature of the crane support permits the storage of equipment and things beneath the crane support without hindering the movement of the crane along the tracks. Optionally, the vessel further has an extension assembly atop which may be deployed a workover rig assembly. The crane may be used to assemble the extension assembly and thus aid in the construction, remediation, and demolition of offshore oil and gas platforms and wells.

Abstract: A vessel is provided that is an improvement over previously disclosed jack-up rigs and lift boats. The vessel has at least three thrusters and is self-propelled. The vessel additionally has a raised and hollow crane support on which a crane may be mounted. The crane support is affixed to tracks, which permit the crane to slide along the deck of the vessel. The raised and hollowed feature of the crane support permits the storage of equipment and things beneath the crane support without hindering the movement of the crane along the tracks. Optionally, the vessel further comprises a sub-base structure removably affixed to the transom of the vessel; a base structure removably affixed to the sub-base structure; and a work-over rig removably affixed to the base structure. Also provided herein are methods of using the crane and affixing the sub-base structure, base structure, and work-over rig to the vessel's transom.

Abstract: A vessel is provided that is an improvement over previously disclosed jack-up rigs and lift boats. The vessel has at least three thrusters and is self-propelled. The vessel additionally has a raised and hollow crane support on which a crane may be mounted. The crane support is preferably affixed to tracks, which permit the crane to slide along the deck of the vessel. The raised and hollowed feature of the crane support permits the storage of equipment and things beneath the crane support without hindering the movement of the crane along the tracks. Optionally, the vessel further has an extension assembly atop which may be deployed a workover rig assembly. The crane may be used to assemble the extension assembly and thus aid in the construction, remediation, and demolition of offshore oil and gas platforms and wells.

Abstract: An extension assembly is provided that comprises spaced apart first and second extension beams, which are removeablely and independently affixed to a deck of a vessel. At least a portion the first and second extension beams extend beyond the transom of the vessel. The assembly further includes a modular traverse beam removeablely affixed to the first and second extension beams along a substantially perpendicular direction. The modular traverse beam is adapted to receive a work-over rig.

Abstract: An extension bridge is provided that comprises at least one modular tank affixed to the deck of a vessel, and a pipe bridge spanning the distance between the at least one modular tank and an offshore platform. Alternatively, the extension bridge comprises spaced apart first and second extension beams, which are removeablely and independently affixed to the deck of a vessel. At least a portion the first and second extension beams extend beyond the transom of the vessel. The extension bridge further includes at least one modular tank affixed to the first and second extension beams and a pipe bridge affixed to the at least one modular tank furthest from the vessel and an offshore structure.

Abstract: A vessel is provided that is an improvement over previously disclosed jack-up rigs and lift boats. The vessel has at least three thrusters and is self-propelled. The vessel additionally has a raised and hollow crane support on which a crane may be mounted. The crane support is preferably affixed to tracks, which permit the crane to slide along the deck of the vessel. The raised and hollowed feature of the crane support permits the storage of equipment and things beneath the crane support without hindering the movement of the crane along the tracks. Optionally, the vessel further has an extension assembly atop which may be deployed a workover rig assembly. The crane may be used to assemble the extension assembly and thus aid in the construction, remediation, and demolition of offshore oil and gas platforms and wells.