A method of elevating the deck area of a marine platform (e.g., oil and gas well drilling or production platform) utilizes a specially configured sleeve support to support the platform legs so that they can be cut. Once cut, rams or jacks elevate the platform above the cuts. The sleeve support is then connected (e.g., welded) to the platform leg and becomes part of the structural support for the platform. In one embodiment, two sleeves are employed. In another embodiment, the jacks or rams elevate in two stages including a first stage wherein one sleeve elevates and the other sleeve does not elevate and a second stage wherein both sleeves elevate together.

The present invention relates to a hydraulic height adjusting device for installing a heavy-weight structure to secure stable horizontal bearing power against a horizontal load of a heavy-weight upper structure. The present invention includes a lower frame which is installed on a top surface of the carrier and is provided with a plurality of receiving portions formed in an upwardly opened shape; and a hydraulic cylinder which is disposed in and engaged to the respective receiving portions of the lower frame, the hydraulic cylinder being moved in a vertical direction to adjust the height of the upper structure, in a state in which an upper end thereof supports the upper structure. The receiving portion is provided with a support guide which is interposed between an inner wall of the receiving portion and the hydraulic cylinder to annually enclose the hydraulic cylinder and thus prevent the hydraulic cylinder from being tilted.

The present invention relates to a hydraulic height adjusting device for installing a heavy-weight structure to secure stable horizontal bearing power against a horizontal load of a heavy-weight upper structure. The present invention includes a lower frame which is installed on a top surface of the carrier and is provided with a plurality of receiving portions formed in an upwardly opened shape; and a hydraulic cylinder which is disposed in and engaged to the respective receiving portions of the lower frame, the hydraulic cylinder being moved in a vertical direction to adjust the height of the upper structure, in a state in which an upper end thereof supports the upper structure. The receiving portion is provided with a support guide which is interposed between an inner wall of the receiving portion and the hydraulic cylinder to annually enclose the hydraulic cylinder and thus prevent the hydraulic cylinder from being tilted.

Systems and method for compensation of motions of a floating structure, which includes a lifting system with a working platform supported by its actuators driven along vertical axis, where the foremost and the aft-most units are paired with each other providing a self-leveling movement; and a balance system, which can freely deviate from its position relative to the deck, with its own actuators and which is arranged to at least one side of the working platform, providing an even distribution of weight enabling the working platform to remain upright and steady, regardless of the floating structure. The lifting system is associated with the balance system by the plurality of arrangements of motion units, which assure the substantially constant angle between the working platform and the working frame, providing free linear movement relative to the working frame regardless of the base structure and the floating structure.

The offshore jack-up has a hull and a plurality of moveable legs engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises moving at least a portion of a vessel underneath the hull of the offshore jack-up or within a cut-out of the hull when the hull is positioned out of the water and the legs engage the seafloor. A stabilizing mechanism mounted on the jack-up is engaged against the vessel. The stabilizing mechanism is pushed down on the vessel to increase the buoyant force acting on the vessel.

A method of building an offshore windmill includes, using a 3D-heave-compensated crane, placing on a windmill pedestal a lifting jack having a receiving region, and fixing the lifting jack to the windmill pedestal such that the lifting jack can be later removed, and such that a windmill column can be placed within the receiving region directly on the windmill pedestal. The windmill generator is installed using the 3D-heave-compensated crane. The windmill column is partially erected on the windmill pedestal using the 3D-heave-compensated crane and the lifting jack. Before the windmill is fully erected, windmill blades are placed on the windmill generator using the 3D-heave-compensated crane, and the erection of the windmill column on the windmill pedestal is completed using at least the lifting jack. Using the 3D-heave-compensated crane, the lifting jack is removed from the windmill pedestal.

A method of building an offshore windmill includes, using a 3D-heave-compensated crane, placing on a windmill pedestal a lifting jack having a receiving region, and fixing the lifting jack to the windmill pedestal such that the lifting jack can be later removed, and such that a windmill column can be placed within the receiving region directly on the windmill pedestal. The windmill generator is installed using the 3D-heave-compensated crane. The windmill column is partially erected on the windmill pedestal using the 3D-heave-compensated crane and the lifting jack. Before the windmill is fully erected, windmill blades are placed on the windmill generator using the 3D-heave-compensated crane, and the erection of the windmill column on the windmill pedestal is completed using at least the lifting jack. Using the 3D-heave-compensated crane, the lifting jack is removed from the windmill pedestal.

Various embodiments relate to a method and a harbour plant for mooring a floating body. The harbour plant includes a piled base structure provided with two upwards through sea level projecting sidewalls terminated above sea level and a laterally arranged bottom structure interconnecting the sidewalls, where a top surface of the bottom structure is arranged at a depth allowing the floating body to be floated in between the sidewalls, and where the floating body is arranged to be rigidly, but releasably supported by at least parts of the sidewalls. The method includes bringing the floating body into a position between the sidewalls and fixing rigidly the floating body to the vertical sidewalls of the base structure and still exposing the floating body more or less fully to buoyancy by allowing a water-filled gap at least between bottom of the floating body and a corresponding upper surface of the base structure.

Various embodiments relate to a method and a harbour plant for mooring a floating body. The harbour plant includes a piled base structure provided with two upwards through sea level projecting sidewalls terminated above sea level and a laterally arranged bottom structure interconnecting the sidewalls, where a top surface of the bottom structure is arranged at a depth allowing the floating body to be floated in between the sidewalls, and where the floating body is arranged to be rigidly, but releasably supported by at least parts of the sidewalls. The method includes bringing the floating body into a position between the sidewalls and fixing rigidly the floating body to the vertical sidewalls of the base structure and still exposing the floating body more or less fully to buoyancy by allowing a water-filled gap at least between bottom of the floating body and a corresponding upper surface of the base structure.

A device includes at least one float. The at least one float is configured to provide a buoyancy force away from a seabed when placed in water. The device also includes an enclosure configured to house the at least one float. The enclosure comprises at least one connection configured to couple the enclosure to a self-elevating unit used in offshore oil operations or offshore gas operations.