Abstract: A transporter for use in a method for removing a jacket for an offshore platform includes an oblong structure rotatable by ballasting, with a sliding saddle which is movable in the longitudinal direction of the oblong structure and adapted for securing the jacket, thus enabling the jacket to be moved in relation to the transporter by the sliding saddle after being attached to the sliding saddle and released from the seabed.

Abstract: There are disclosed two embodiments of a subsea drilling, completion and/or workover apparatus which includes a spar buoy having a well therethrough, and a riser which extends through the well in the buoy for connection to the subsea wellhead during the drilling and/or completion process. A buoyancy tank is disposed about the riser within the buoy well to support the riser, and the upper end of the tank is fee to move vertically with respect to the well deck so that it will not be placed in compression despite anticipated rise and fall of the buoyancy tank.

Abstract: A marine terminal has a cargo crane for directly transferring cargo between two marine vessels or between a marine vessel and a land-side vehicle. The marine terminal may comprise a wharf having a docking side along which marine vessels dock, and a cargo crane movable lengthwise along the wharf for directly transferring cargo from a vessel docked alongside the wharf to a land-side vehicle, such as railcars or trucks. The marine terminal may comprise a pier having opposed docking sides, and a cargo crane movable lengthwise along the pier for directly transferring cargo from a vessel docked along one docking side of the pier to a vessel docked along the other docking side of the pier.

Abstract: A method and apparatus that eliminates the need for a derrick barge to lift the deck into place on a floating offshore structure. A connector is used to connect the transport barge to the floating offshore structure. The connector is a type that allows only relative pitch motions between the transport barge and floating offshore structure in response to sea states acting on the barge and floating offshore structure. The connector is also a type that allows disconnection while large forces are acting on the connector. One or more skidding girders attached to the legs of the deck support the legs of the deck above the skidding surface of the transport barge. A skidding surface on the girders, and complementary skidding surface on the surface of the transport barge and floating offshore structure, allow the deck to be skidded from the barge to the floating offshore structure.

Abstract: A device for lifting a sea-going structure (C), such as a drilling platform consisting of a superrstructure (B) and a jacket (J), which device consists of a flotation body (1) such as a boat provided with one or more laterally slidable lifting devices (2), wherein each lifting device (2) is provided with a coupling member (5) for fixing on a part of the substructure which is arranged for movement in all directions relative to the lifting device (2), whereby the device adapts better to the swell and the relative displacement of the flotation body (1) relative to the drilling platform.

Abstract: The present invention relates to a method of manufacturing a tank which is too large to be built on the ground. In the method, a floating station (1012) is built on the sea, surrounding a first spherical shell section (1002a) which constitutes one end of the tank. In the floating station, a hollow cylindrical section is built in a vertical position, connected to the first spherical shell section. The second spherical shell section (1002b) constituting the other end of the tank is connected to the open end of the hollow cylindrical section.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and the deck package. Each boom has a lifting end portion with a roller that fits a receptacle on the package. Tensile connections form attachments between the deck package and barge at a lower elevational position. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and the deck package. Each boom has a lifting end portion with a roller that fits a receptacle on the package. Tensile connections form attachments between the deck package and barge at a lower elevational position. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: A system transfers, at sea, a load onto fixed legs of a substructure emerging from water. The load is specially fabricated in the construction yard and is transported to the substructure by a suitable cargo barge. The load and the substructure have a corresponding number of legs. The transfer system includes a preload mooring subsystem in front of the substructure. A horizontal sheave can be opened and is used to shift a mooring wire from one position to another. The transfer system also includes a subsystem to mate the load to the substructure. This mating subsystem has a main transfer or extender, called an ALS, installed on legs of the load. Also, the mating subsystem has a secondary transfer or cargo barge release, called a BRS, installed on the cargo barge. Furthermore, the transfer system includes a subsystem to protect the barge sides and the legs of the substructure. Finally, the transfer system includes a cargo barge arrest subsystem.

Abstract: A marine terminal has a cargo crane for directly transferring cargo between two marine vessels or between a marine vessel and a land-side vehicle. The marine terminal may comprise a wharf having a docking side along which marine vessels dock, and a cargo crane movable lengthwise along the wharf for directly transferring cargo from a vessel docked alongside the wharf to a land-side vehicle, such as railcars or trucks. The marine terminal may comprise a pier having opposed docking sides, and a cargo crane movable lengthwise along the pier for directly transferring cargo from a vessel docked along one docking side of the pier to a vessel docked along the other docking side of the pier.

Abstract: An offshore jacket or compliant tower and method of installing an offshore jacket or compliant tower where the foundation piles do not initially support the jacket. The foundation piles are driven into the sea floor. Two or more temporary support piles are driven into the sea floor. Two or more docking piles are driven into the sea floor and extend a greater height above the sea floor than the foundation piles and the temporary support piles. The jacket, which includes flexpiles, is lowered into position such that it receives the docking piles. The docking piles locate and position the jacket above the temporary support piles and the foundation piles. The jacket is provided with vertical steel tubes that correspond to the location of the temporary support piles. A bulkhead in each vertical steel tube is vertically located such that the jacket is supported and leveled by the temporary support piles and not the foundation piles.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and the deck package. Each boom has a lifting end portion with a roller that fits a receptacle on the package. Tensile connections form attachments between the deck package and barge at a lower elevational position. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: In a tension-leg mooring system a production platform supporting one or more decks above the water surface for accommodating equipment to process oil, gas, and water recovered from a subsea hydrocarbon formation is mounted on a single water surface piercing column formed by one or more buoyancy tanks located below the water surface. The surface piercing column includes a base structure comprising three or more pontoons extending radially outwardly from the bottom of the surface piercing column. The production platform is secured to the seabed by one or more tendons per pontoon which are secured to the pontoons at one end and anchored to foundation piles embedded in the seabed at the other end.

Abstract: A shallow draft floating offshore drilling/producing structure. The structure is formed from a buoyant hull on which one or more modules or decks may be placed to support process equipment, a drilling rig, utilities, and accommodations for personnel. Drilling and/or producing is accomplished through a center well in the hull. The hull includes fixed ballast, an oil storage area, and voids and variable ballast for offsetting the lighter weight of the stored oil. The hull is designed to have a relatively small water plane area. The hull is also designed to have roll and pitch periods that are detuned from waves in the area that the hull is to be installed.

Abstract: A method for removing a superstructure from a jacket placed on a sea-bottom, wherein a vessel is positioned in the vicinity of the jacket. In this operation, the problem of the superstructure colliding with the jacket during lifting thereof due to up and down movement caused by the vessel floating on the waves is real and present. The superstructure and/or the jacket can sustain damage. To avoid such damage, the superstructure is engaged by lift supports which are movable relative to the vessel. Once the movement of the vessel in the waves is detected, lifting of the superstructure from the jacket is started when it is detected that the vessel is situated below it's average depth level in the sea.

Abstract: A modular caisson installation demountably installed at a preselected water site. The modular caisson installation includes a plurality of caissons having tops and bottoms and being individually demountably installed in a predetermined configuration at a preselected water site with the caisson bottoms removably seated on a bed at the preselected water site. The caissons being constructed of one or more floatable sections each being fluid trimmable and fluid ballastable and having means for trimming and ballasting the section with fluid to effect controlled lowering and positioning thereof during formation of the installation and controlled raising and removal thereof by floatation to enable demounting of the installation.

Abstract: A means (20) for protecting a device (2) which a installed on the sea bed (11) and projects up therefrom. The means comprises a central section (21) which is arranged to be attached to the upper section (9) of the device (2), and legs (22) which are linked to the central section (21) and arranged to extend away from it and slantingly down to the sea bed (11). The legs (22) can be pivoted into a position, wherein their longitudinal direction is substantially coincident.

Abstract: A construction jack-up barge comprising a barge (11) supporting a tower (13) in a stowed horizontal position for transport and a vertical position for deployment. The tower (13) has three fold-out legs (15), each equipped with a footing assembly (17). The tower (13) is supported for rotation between a horizontal stowed position and a vertical position for deployment, about the barge (11), by a pivotal connection (19). The tower is also supported in a traveling frame (20) which has concave shaped rollers (21) which track each chord of the tower (13), allowing the tower (13) to be moved up and down relative to the barge (11), when the tower is being deployed. In the vertical position the tower (13) is received through an opening which extends through the deck to the hull of the barge (11). A central cut out portion (33) extends from the stern of the barge (11), to the opening, to provide a pathway for the tower (13) as it rotates between the horizontal and vertical positions.

Abstract: In case of constructing a gravity-type marine structure at a spot with a comparatively great depth of water, a footing 2 serving as a float is constructed in a dry dock, and a cylindrical body 4 constituting an underwater substructure is constructed on the footing 2 in a shallow sea yard. The cylindrical body 4 is telescopically assembled and an upper cylinder 4C is made to function as a float. Ballast water W.sub.b is filled in the footing 2 at the installing spot with a great depth of water to submerge the footing 2, and a lower cylinder is extended with the upper cylinder 4C as a float. After the footing 2 has landed, the footing 2 and the cylindrical body 4 are charged with a filler, and an upper structure on the sea is constructed on the upper part of the cylindrical body 4.

Abstract: A plurality of floatable modular caissons are constructed onshore, either in whole or in part, towed to a desired site for port and harbor construction, expansion or modernization, precisely trimmed and ballasted down, and assembled in different combinations to form marine structures and/or integrated marine structures/marine cargo terminals to construct breakwaters, breakwater piers, bulkhead wharves, wharves and piers. The breakwaters and/or breakwater piers are arranged to form a protected port or harbor and are designed to withstand maximum force waves and winds at the harbor site. As an integral part of the breakwater piers, modular caissons are assembled to form marine cargo terminals, such as liquid bulk terminals and LNG/LPG terminals.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and deck package. Slings are suspended from a compression frame portion at the boom end portions of the truss assembly. The slings form attachments between the compression frame and the deck package at the upper elevational positions on the deck package. Tensile connections form attachments between the deck package and barge at a lower elevational position. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: A method is disclosed for redeploying an offshore platform structure from a first site to a second sight of different water depth in which the connection is released between a subsea jacket base and a plurality of piles which are anchored in the ocean floor at the first site. The offshore platform structure is vertically raised by pumping air into a tank member at the top of the subsea jacket base and the surface tower which is supported upon subsea jacket base is reworked while the jacket base is vertically raised. This operation is less difficult than attempting operations offshore on a horizontally disposed surface tower. The offshore platform structure is transported to the second site and the tank member is ballasted to vertically lower the offshore platform to the second site where it is installed.

Abstract: A support structure for use with at least two wells, and a method for providing and supporting at least two wells in the ground beneath a body of water, includes a caisson, a plurality of conductors, and a guide frame, which support at least two wells without the use of any piles or brace members, the at least two wells being supported solely by the conductors, the caisson, and the guide frame.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and the deck package. End caps are removably connected to each of a two diagonally extending, longitudinal members of a boom portion of the truss assembly. Upper and lower connections form attachments between the end caps and the deck package at the upper elevational positions on the deck package. Tensile connections form attachments between the deck package and barge at a lower elevational position. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: An offshore structure is disclosed for placement on a sea floor foundation located in a body of water containing moving ice masses and water waves. The offshore structure has a foundation base which contacts the sea floor foundation and at least three stepped stages which are stacked above the foundation base. Each stage has an outer hull to engage moving ice masses and water waves. Additionally, each stage has an outer horizontal diameter which is smaller than the outer horizontal diameter of the stage immediately below it.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and the deck package. Upper and lower connections form attachments between the truss members and the deck package at upper and lower elevational positions on the deck package. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: An offshore apparatus and method for oil operations at a deep water well site wherein a lower hull includes a pontoon portion providing a large water plane area and also includes an upwardly facing body opening, an upper hull is fabricated within said body opening in fully telescoped relation therewith, said upper hull and lower hull being vertically relatively movable, and a deck carried by the upper hull. The pontoon portion has suffient displacement to support the apparatus in towing draft mode. The lower hull and upper hull include floodable compartments for selective ballasting and deballasting to raise and lower the hulls relative to each other in order to submerge the apparatus under stable conditions and to change the draft from towing mode to operating mode in which the hulls are in extended nontelescopic relation at a selected draft. Support lines interconnecting the lower hull and deck are selectively tensioned to aid in the transition from towing draft to operating draft.

Abstract: A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and the deck package. Upper and lower connections form attachments between the truss members and the deck package at upper and lower elevational positions on the deck package. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Abstract: An offshore platform structure is disclosed for temporarily using a jack-up rig for well operations in deepwater applications having a bottom founded jacket base which supports a surface tower which extends above the ocean surface and a subsea rig support interface which is adapted to support the jack-up rig for well operations. At least one selectively buoyant rig support buoyancy tank connected to the rig support interface whereby a portion of the temporary load on the jacket base in supporting the jack-up rig for drilling operations may be alleviated.

Abstract: The deck or superstructure for an offshore production platform is shifted from a loading facility onto a cargo vessel that includes a large-area lifting assembly. The vessel transports the superstructure to a previously-installed substructure. On site, the elevator assembly raises the superstructure above the top of the substructure jacket, aligns the superstructure with the substructure and then mates the two together by lowering the elevator assembly. The elevator assembly is designed to break away very rapidly from the superstructure to compensate for vessel rebound when the mass of the superstructure is accepted by the substructure.

Abstract: A method is described for using a particular spring element to facilitate the transfer of deck modules to a hull or jacket during the construction of an off-shore well platform. The spring element not only absorbs energy from the compressive loading expected during the transfer, but also resists any shear loading caused by relative motion between the module and the jacket or hull caused by the operation being performed in a body of water. The spring element includes two significantly different resistances to crushing when subjected to compressive loading including an initial resistance during which significant energy is absorbed. The spring element is also provided on the carrier barge between the barge and the deck module so that if the carrier barge should reengage the module once the transfer has been started, damage will be inhibited.

Abstract: An offshore tension leg platform having a deck, a hull, and a plurality of elongate tendons securing the hull to an ocean floor foundation provides full well workover and production capabilities for autonomous operation and can be installed and operated in any water depth and sustains any environmental loading conditions. The hull supports well risers of well trees located below the water surface at an elevation in close proximity to the connections of the tendons to the hull. Alternatively the risers and trees may be supported above water by a deck or the trees may be located on the seabed. A workover platform supported by a perimeter trackway on the deck may be positioned over any of the well risers for workover operations. Liquid products may be exported from the platform via a pipeline or to a floating tanker. The hull is configured to minimize loadings in the tendons. All components are installed by a drilling vessel without the need for special installation vessels and equipment.

Abstract: An offshore platform structure is disclosed for temporarily using a jack-up rig for well operations in deepwater applications in which a jacket base supports a surface tower and a subsea rig support interface adapted to accept the jack-up rig for well operations. The bottom founded jacket base is designed for dynamic response with the mass of the jack-up engaged and at least one ballastable rig support buoyancy tank connected to the rig support interface whereby the weight of the jack-up rig is substantially offset by buoyant forces supplied by the rig support buoyancy tank when the jack-up rig is deployed on the jacket base and the mass of the jack-up rig is substantially replaced in the offshore platform structure by ballast in the rig support buoyancy tank when the jack-up rig is removed.

Abstract: A tower structure for offshore oil and gas fields is formed from various vertically spaced and interconnected tower sections. At least one of the tower sections is rotated about a vertical axis relative to another section so as to define a twisted portion. The number and orientation of the tower sections are varied depending on the particular environment and, particularly the water depth where the tower structure is located.

Abstract: In this method of putting an offshore platform deck into place on a support structure by means of a ballastable barge and of a plurality of cylinder and plunger piston assemblies, it is possible to avoid shocks between the pistons and the support structure, and also between the legs of the deck and the support structure, which shocks are due to vertical movements of the deck driven by the swell during the operations of putting the deck into place. This is done by providing in each leg: a low pressure hydraulic fluid accumulator; first controllable means for establishing high flow rate bidirectional communication between the accumulator and a chamber of a cylinder of the cylinder and plunger piston assembly, above the plunger piston; second controllable means for establishing high flow rate unidirectional communication from the accumulator to the chamber; and third controllable means for establishing low flow rate communication between the chamber and a hydraulic fluid reservoir.

Abstract: The present invention is a method for reducing the natural period of the second harmonic response in a deepwater compliant tower by decoupling the mass of the production risers from the vertically extending compliant framework.

Abstract: A compact offshore tension leg platform having a deck, a hull, and a plurality of elongate tendons securing the hull to an ocean floor foundation provides full well workover and production capabilities for autonomous operation and can be installed and operated in any waterdepth and sustain any environmential loading conditions. The hull supports the well risers of well trees located below the water surface at an elevation in close proximity to the connections of the tendons to the hull. Alternatively the risers and trees may be supported by the deck. A well workover platform, supported by a circular perimeter trackway on the deck may be positioned over any of the well risers for workover operations. Liquid products may be exported from the platform via a seabed pipeline or to a floating tanker moored to a mobile offtake on the deck support column. The hull is configured to minimize loadings in the tendons.

Abstract: A different approach to tender assisted drilling which has the flexibility to be used with multiple jack-up rigs, and nearly any type of fixed offshore production platform. A skid base includes distinct capping beam feet and skid-off feet, the former adjustable to capping beam spacing and the latter restricted to support of the skid base upon cantilever beams. A special swivel mechanism and sliding mounting in the capping beam feet, and a vertical jack in the aft skid-off feet, enable the skid base to be transferred to the fixed platform simply by aligning them over the capping beams and depressurizing the skid-off feet. Thus, walking mechanisms may be swivelled and oriented upon the capping beams, notwithstanding relative movement between the jack-up rig and the platform. The skid base is simply walked across from the cantilever beams to the platform.

Abstract: A method and apparatus for transporting and installing a deck of an offshore platform onto a substructure without requiring heavy lift cranes. The towing vessel or semisubmersible vessel is configured with a cutout or opening therein that surrounds the substructure onto which the platform is to be placed. The platform is transported in an elevated position upon the semisubmersible vessel and it spans across this opening such that once the semisubmersible vessel is properly positioned (i.e. the elevated platform being positioned over and in alignment with the substructure), the semisubmersible vessel is rapidly ballasted thereby transferring the platform onto the substructure.

Abstract: A method and apparatus for transporting and using a drilling apparatus or a construction crane apparatus from a single moveable vessel is provided. Either a drilling apparatus or a construction crane apparatus is skidded onto the deck of a jack-up rig which is then floated to a remote location for use of the apparatus. The skidding of the construction crane apparatus is facilitated by a new and unique pony structure to raise the base of the construction crane apparatus above a skid on the jack-up rig.

Abstract: The present invention relates to a water area structure using a placing member for underwater ground, which is used as, e.g., a water area structure for discharge such as a shore-bridge and a jetty, a bulkhead structure, a breakwater structure, a dike structure, and the like.

Abstract: Disclosed is a modular offshore platform for use in water depths of 160 feet and less. The jacket assembly of the structure is composed of interchangeable stackable modular units. The horizontal cross section of the jacket assembly has a truncated triangular configuration. Some of the vertical members of modules of the jacket assembly are adapted to allow the passage of piles which function as conductors and some of the vertical members are adapted to allow the passage of piles only. The jacket assembly is designed to lie well beneath the water surface so that it is not subject to great wave forces and does not need to be battered.

Abstract: An offshore base-supported column structure for installation in the water on an offshore floor having an elongate column vertically supported entirely from a column foundation on the offshore floor and releasably engaged to the foundation with the top of the column extending above the offshore water level. A column support base is supported from the offshore floor and engages and provides lateral support for the column with a slidable connection. A support structure is connected to the top of the column above the water level.

Abstract: A system is provided for installing a drilling template in a level orientation over an ocean floor. The drilling template is supported on a plurality of preset piles. The piles extend above the ocean floor. After the piles are set, their elevations are accurately determined, and pile-receiving sockets in the drilling template are finally fabricated to have depths corresponding to the respective piles to be received therein. Once the drilling template is lowered onto the piles, it is supported in a level orientation.

Abstract: A method for building and assembling an offshore platform whose normal draft exceeds the depth of waterways between the building site and use location of the platform. The hull and deck of the platform are built separately in a shallow graving dock. The deck is then elevated, the graving dock partially flooded and the hull floated into position and mated to the deck. A modified form of the invention is the building of the hull and deck as a single structure and use of the barge to support a portion of the weight of the platform. The graving dock is then flooded to maximum depth, a barge is floated under the deck and ballasted down to a select draft. The barge is attached to the deck and then deballasted to partially support the platform structure and reduce its overall draft.

Abstract: A method and apparatus for installation of heavy, ballastable, gravity fundament structures on the sea bottom at large depths. In accordance with the invention, there is utilized air, water, and a liquid lighter than water in various proportions and combinations to provide the structure with the required buoyancy and submerged weight during the sequential phases of the transport and descent operations in order to finally position the structure in a selected location on the sea bottom. Various modes can be used to accomplish the descent and the structure may in a final stage be penetrated down into the sea bottom to a sufficient degree.

Abstract: A platform comprises a hull mounted on legs such that it can be moved relative to the legs be by jack mechanisms disposed in a carrying structure. The jack mechanisms include a plurality of output gear pinions which cooperate with racks mounted along at least a part of the length of the legs. The hull is provided with a first device for applying an overload on the leg through the jack mechanisms. A second overload device is also provided an includes at least one additional load which is temporarily and directly lockable to each leg of the platform when the legs are being set on the sea bed.

Abstract: An offshore deck or platform unit is provided with depending legs having shock absorbing stabbing tip assemblies for engagement with the upstanding columns of a marine substructure to transfer the weight of the deck to the substructure by positioning the deck relative to the substructure with a barge and ballasting down the barge to move the deck into engagement with the substructure. The barge also carries a deck support structure comprising plural sand jack assemblies which provide for disengagement of the barge from the deck. The stabbing tip assemblies include coaxially arranged primary locating pins which are dropped into position to hold the location of the deck relative to the columns and annular resilient collars for transferring vertical and lateral shock loads between the columns and the deck during the transfer process.

Abstract: A method for horizontal mating of multiple floating sections of an offshore platform using a single point mooring is disclosed. The single point mooring is installed at a predetermined mating site. The first section of the platform is transported to the mating site. Anchor handling vessels tow the section to the single point mooring and connect it to that mooring. Subsequent sections of the platform are then transported to the mating site while an anchor handling vessel attends to the horizontally floating moored sections. When all sections have been mated together at the mating site, the platform is disconnected from the single point mooring and towed to the installation site.

Abstract: A method of installing an integrated deck onto an offshore platform substructure. The integrated deck is held by a support structure on a barge and transported to a preinstalled offshore platform substructure which is adapted to receive the barge and allow aligning of the integrated deck with the substructure for mating operations. Once the barge is positioned within the substructure, tethers are connected between the barge and anchoring foundation elements to moor the barge. Then the tethers are tensioned to minimize both vertical movement and lateral movement caused by wave action. Mating of the integrated deck and the substructure proceeds while tension loads in the tethers are maintained.