Quick release system for topsides float-over installation on offshore platforms

The present invention provides a system and method that keeps a barge and grillage system on the barge in compression with a topsides supported by the grillage system during the transport, while providing a quick release system between the barge, grillage system, and topsides during an installation procedure that transfers the topsides to an offshore platform. The quick release system can be in tension to apply a compressive force between the grillage system and the topsides until the quick release system is released.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention disclosed and taught herein relate generally to topsides for offshore platforms and related installation methods; and more specifically related installation methods and systems to release quickly the topsides from one or more associated barges temporarily supporting the topsides for the offshore platforms.

2. Description of the Related Art

Offshore platforms provide an infrastructure for drilling, production, or other functions of offshore energy production. The platform includes a lower structure that is at least partially submerged and an upper structure, known as a topsides or deck, above the water level that contains drilling or production equipment, cranes, living quarters, and the like. In shallow water, fixed offshore platforms can be supported by the seabed. In deeper water, floating offshore platforms are typically moored to the seabed due to the difficulty of rigid placement to the sea floor.

One type of a floating offshore platform is a Spar. A Spar is a type of floating oil platform typically used in very deep waters and is among the largest offshore platforms in use. A Spar includes a large cylinder or hull supporting a typical topsides. Due to its size of hundreds of meters in length, the Spar hull is typically floated horizontally to the installation site, and upended in the water, and then the topsides mounted to the hull. The hull does not extend all the way to the seafloor, but instead is moored by a number of mooring lines. Typically, about 90% of the Spar is underwater and is considered a “deep floater.” The hull serves to stabilize the platform in the water, and allows movement to absorb the force of potential high waves, storms or hurricanes. Low motions and a protected center well also provide an excellent configuration for deepwater operations.

Deck or topsides installation is typically a challenge for offshore platforms, particularly for deep draft floaters like the Spar, because the Spar must be upended after transportation to the location site. In the past heavy lifting vessels (“HLV”), including but not limited to, derrick barges have been used for topsides installations on the Spar after upending. Traditionally, the topsides of a floating offshore platform requires multi-lifting, for example five to seven lifts, to install the whole topsides due to the lifting capacity of available HLV. Due to multi-lifting, the steel weight per unity area of the topsides can be higher than that of topsides of any platforms (fixed or floating) installed with a single lifting. If the weight of the topsides is reduced, the weight of the Spar hull may also be reduced.

The same or similar principles are applicable to other offshore platforms to which a topsides can be mounted, whether fixed or floating. The challenge is to mount a large, heavy topsides to the rest of the platform in an offshore or near shore location, where the availability and capacity of lifting vessels may be less than optimum.

One or more barges are generally used to transport a topsides to a floating portion of the offshore platform, such as a Spar hull, for installation thereon. Recently catamaran float-over systems have been used to install the topsides onto the Spar hull. A float-over method is a concept for the installation of the topsides as a single integrated deck onto a Spar hull in which the topsides is first transferred onto at least two barges (called “offloading”) and transported with the barges to the installation site for the Spar hull. At the installation site, the barges are positioned on both sides of the Spar hull with the Spar hull below the topsides, the elevation is adjusted between the topsides and the Spar hull, and the topsides is installed to the Spar hull. Installation of the topsides to the Spar hull by the float-over method can allow a high proportion of the hook-up and pre-commissioning work to be completed onshore prior to load-out, which can significantly reduce both the duration and cost of the offshore commissioning phase. The float-over installation method allows for the installation of the integrated topsides or production deck on a fixed or floating platform structure without any heavy lift operation.

FIG. 1is an exemplary top schematic view of a topsides loaded on two barges in a catamaran system. In general, a catamaran system100includes at least a pair of barges115a,115b(generally115) spaced a distance from each other. A fabricated topsides110is removably coupled to the barges115through a supporting structure, referenced herein as a grillage system125a,125b(generally125) mounted to the barges115a,115b, respectively. The grillage system has attachment points135for the topsides on each barge. The number of attachment points can vary depending on the load and size of the topsides and the barges. In general, at least two attachment points are used for each barge, although the number can vary from one to many. In the illustration, barge115awith grillage system125ahas at least two attachment points135a′,135a″ and barge115bwith grillage system125bhas at least two attachment points,135b′,135b″.

Different loads occur on the catamaran system100that are not prevalent in a single barge system due to the separation of the barges. During loading and transportation to the desired location, the catamaran system is subjected to several loading conditions primarily due to wave action on the separated barges.

The topsides is typically maintained on the grillage system by gravity. While some operations connect a fork with a locking plate around a guide pin to restrict lateral movement between the topsides and the barges, the vertical movement is not constrained because the fork and locking plate are not welded to the guide pin.

Some efforts have restrained the topsides vertically with additional members welded to other portions of the grillage system besides the guide pin. However, these weldments are removed prior to the complete transfer of the topsides to the hull, and necessarily allow the undesirable vertical movement. Thus, during the transfer, the topsides, partially supported by the hull, can impact the grillage system on the barges by the differential motion between the floating barges and the Spar hull. The impacts can cause system wide shock waves throughout the structures from repetitive impacts on each other, accompanying structural damage, and possible sensitive equipment failure. It is difficult for personnel to cut welds at each weldment in a timely manner to release the restrained topsides from the barges while wave action is causing significant differential movement between the barges and the Spar hull.

Therefore, there remains a need to provide a system with a topsides that can be restrained vertically but released timely upon becoming supported with an offshore platform during an installation procedure.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a system and method that keeps a barge and grillage system on the barge in compression with a topsides supported by the grillage system during the transport, while providing a quick release system between the barge, grillage system, and topsides during an installation procedure that transfers the topsides to an offshore platform. The quick release system can be in tension to apply a compressive force between the grillage system and the topsides until the quick release system is released.

The disclosure provides a method of loading a topsides onto an offshore platform, comprising: positioning a topsides having a weight in proximity to one or more barges having a grillage system and the grillage system having at least one attachment point for the topsides; transferring at least a portion of the weight of the topsides to the one or more barges; laterally coupling the topsides to the at least one attachment point on the grillage system on the one or more barges; vertically coupling the topsides to the grillage system with at least one quick release system; transporting the topsides and the one or more barges to the offshore platform; adjusting a relative elevation between the topsides and the offshore platform; transferring at least a portion of the weight of the topsides to the offshore platform; laterally uncoupling the topsides from the at least one attachment point on the grillage system on each barge; and vertically uncoupling the topsides from the grillage system by actuating the at least one quick release system.

The disclosure also provides a system for loading a topsides onto an offshore platform, comprising: a topsides having a weight supported on one or more barges having a grillage system and each grillage system having at least one attachment point for the topsides; a means for laterally coupling the topsides to the at least one attachment point on the grillage system on each barge; a means for vertically coupling the topsides to the grillage system with at least one quick release system; a means for laterally uncoupling the topsides from the at least one attachment point on the grillage system on each barge; and a means for vertically uncoupling the topsides from the grillage system by actuating the at least one quick release system.

DETAILED DESCRIPTION

The present invention provides a system and method that keeps a barge and grillage system on the barge in compression with a topsides supported by the grillage system during the transport, while providing a quick release system between the barge, grillage system, and topsides during an installation procedure that transfers the topsides to an offshore platform. The quick release system can be in tension to apply a compressive force between the grillage system and the topsides until the quick release system is released.

The installation of the topsides onto an offshore platform, such as a Spar hull, can involve several major steps. The Figures illustrate various steps of an exemplary procedure to achieve preloading on a catamaran system that can be used to install one or more topsides on an offshore platform. Each figure will be described below in the context of a Spar hull with the understanding that the same or similar procedure can be used with other offshore platforms, including those with variable elevations as floating offshore platforms, and those with a fixed elevation where the barges can provide variable elevations relative to the platforms. Further, it is expressly contemplated that the quick release system can be used with one barge sufficiently large to transfer the topsides to the offshore platform, and thus, the float-over procedure described herein is only exemplary in explaining the underlying aspects of the invention. The term “barge” herein is used broadly to include a barge suitable to be used for a float-over procedure described herein, a single barge configured to transport a topsides to the offshore platform for installation thereon, and other types of transportation vessels suitable to transport the topsides.

An initial step is to load the topsides from the fabrication yard onto the deck of a transportation barge and then tow the transportation barge from the fabrication yard to a sheltered location, including, but not limited to, a quayside location. A quayside location is a structure built parallel to the bank of a waterway for use as a landing place. A next step is to transfer the topsides from the transportation barge to at least one barge, and generally at least two barges, at the sheltered quayside to create a catamaran system that will be used to install the topsides on a Spar hull.

FIG. 2Ais a schematic end view of an exemplary embodiment of a topsides being offloaded from a single transportation barge to two barges.FIG. 2Bis a schematic top view of a detail portion of the topsides fromFIG. 2Ato be coupled with a portion of the grillage system. The figures will be described in conjunction with each other.

A single transportation barge105can be loaded with the topsides110from a fabrication facility and towed into proximity to one or more barges115aand115b(generally115) for offloading thereon. The barges115spaced a distance from each other together with the topsides loaded thereon creates a catamaran system100for towing or otherwise transporting the topsides to the Spar hull (not shown) for an exemplary float-over procedure described herein. The barges115are designed to provide buoyancy for the load of the topsides110and withstand environmental load of sea and weather conditions during the catamaran towing of the topsides to the Spar hull.

Each of the two barges115has a grillage system,125aand125b(generally125). The grillage system125generally has an array of beams and crossbeams (or just a beam; not illustrated) with attachment points for the topsides, such as described below.

The topsides110is provided with a fork130a,130b(generally130) on the topsides. The attachment points135of the grillage system125is provided with a tall installation guide pin131a,131b(generally131). The forks130on the topsides are designed to guide the barge's grillage systems125to a coupling position with the topsides using the installation guide pins131. An actuator210acan be coupled to the barge115a, such as coupled to the grillage system125aon such a barge, and an actuator210bcan be coupled to the barge115b. An embodiment of the actuators210a,210b(collectively, “210”) and their relation to the quick release system is described in more detail below in reference toFIGS. 5A-7, with another embodiment described in reference toFIGS. 8A-8D, and another embodiment described in reference toFIGS. 9A-9D.

Another step is installing sea fastening members to secure the grillage systems mounted to the barges with the topsides.

FIG. 3Ais a schematic end view of an exemplary embodiment of a topsides coupled to the grillage system of the barges.FIG. 3Bis a schematic top view of a detail portion of the topsides and the grillage system fromFIG. 3Awith sea fastening coupled between an attachment point of the grillage system and the topsides. The figures will be described in conjunction with each other.

The grillage system125can provide a number of hingeable couplings to connect with the topsides. The nature of the fastening can create a solid hinge system that is bendable in response to loading on the topsides relative to the barges. The term “hingeable” coupling is used broadly and is not limited to a pair of plates rotating about an enclosed pin. For example, a hingeable coupling can include a bendable coupling that can flex and bend as needed or one that is constrained significantly in one plane and flexibly located in another plane. Examples are described herein. Also, it should be appreciated that a person of ordinary skill could design the grillage system with any number or type of supports and in any configuration to accomplish the goal of creating a catamaran system100. As one example, when the fork130of the topsides is engaged with the guide pin131on a barge, a locking plate132b(generally132) with an opening suitable for a guide pin can be placed on the side of the guide pin131opposite the fork130and welded or otherwise coupled to the fork to entrap the guide pin therebetween to restrict lateral movement. Alternatively, the locking plate132can have an opening, such as a hole, that is sized to surround the guide pin131, and be placed over the guide pin and coupled to the fork130to restrict lateral movement.

This coupling of the fork130with the locking plate132restricts the horizontal movement between the topsides and the barge, but still allows vertical or bending movement, because the fork and the locking plate are not welded to the guide pin. Further, the fork can be made of plate steel, such as and without limitation 1 inch (25 mm) thick plate, that relative to the mass of the topsides forms a bendable solid hinge128a,128b(generally128), and can flex as needed for bending movement between the topsides and the barges.

In general, the topsides fork130and guide pin131will be coupled near a lateral center of gravity134a,134b(generally134) of the barges115a,115b, respectively. The lateral center of gravity will be generally the center of the barges from side to side when the barges are constructed symmetrically from side to side. The coupling can occur along the length of the barge at one or more longitudinal attachment points. When multiple lateral attachment points are used to couple the topsides to the barge through the grillage, the coupling can be made effectively at the lateral center of gravity, for example, where two lateral attachment points might be equidistant from the lateral center of the barges, so that the result is an effective coupling through the center of gravity, as might be present in a single barge configuration.

Further, after the topsides' weight is transferred to the barges115, the middle barge105can be pulled out. In general, the barge105can be removed after the topsides is secured at least laterally to the barges115, such as with the locking plate132.

In at least one embodiment, the topsides110can be supported by at least two and advantageously four attachment points135of the grillage system125with the forks/locking plates and guide pins along the length of the barges115. However, a person of ordinary skill could design any number of supporting locations and mechanisms for the topsides110on the barges115.

FIG. 3Cis a schematic end view of a detail portion of a bracing member on the topsides fromFIG. 3Adisposed above a portion of the grillage system adjacent to the barge.FIG. 3Dis a schematic side view of the bracing member ofFIG. 3C. The figures will be described in conjunction with each other.

Another hingeable coupling at a hinge between the topsides and barges can be made by coupling a tie down bracing member120a,120b(generally120and also shown inFIG. 2A) between the topsides110and the grillage system125on each barge. The bracing member120can include a center tubular member121b(generally121) and an extendable plate122b(generally122). The tubular member121can include a slot124b(generally124), shown particularly inFIG. 3C, through which the plate122is slidably coupled. One or more fasteners123b(generally123) such as wire rope or chain, can secure the plate122in a retracted position in the tubular member121. In at least one embodiment, the tie down bracing members120are not welded to the barges until substantially all the weight of the topsides is transferred from the transportation barge105to the barges115.

The tie down bracing member120in a retracted position can be positioned above a tie down structure127a,127b(generally127) of the barges115, adjacent the barge inner edge shown inFIGS. 3C-3D. The bracing member120is generally disposed laterally inward from the center of gravity134of the barges and toward a center of the topsides. In at least one embodiment, the bracing members120on the between the topsides and the barges (such as the grillage systems coupled to the barges) reduces the length of an unsupported portion of the topsides between the guide pins131.

FIG. 4Ais a schematic end view of an exemplary embodiment of a topsides coupled to the grillage system of the barges with all the sea fastenings installed.FIG. 4Bis a schematic end view of a detail portion of the topsides fromFIG. 4Acoupled with the barge using the sea fastenings.FIG. 4Cis a schematic side view of a detail portion of the bracing member coupled between the topsides and the barge fromFIG. 4B.

After the load of the topsides110is transferred from the transportation barge to the barges115, the bracing member120, specifically the plate122, can be dropped down and welded to the tie down structure127, as shown inFIGS. 4B-4C. Further, the plate122can be welded to the tubular member121, so that the coupling between the topsides and the grillage system is fixed in length. The plate122can be made of two, thin side plates welded to the support structure and one thicker middle plate with stiffeners coupled to the support structure, that relative to the size of the topsides forms a bendable solid hinge that can flex as needed for bending movement of the topsides relative to the barges. Thus at this time, the topsides110is secured with the grillage system125laterally around the guide pins131and vertically with the bracing members120.

The grillage system125of supports and bracing members make the topsides-barge system similar to a rigid catamaran with hinged links at sea fastening members, such as the fork130/locking plate132and bracing member120, thus creating the catamaran system100.

FIG. 5Ais a top schematic view of a topsides loaded on two barges according to the invention with at least one quick release system. Another step is coupling a quick release system180between the topsides110and the grillage system125that is coupled to the barges115. Thus, the topsides is restrained vertically through the grillage system ultimately to the barges with the at least one quick release system. The number of quick release systems180can vary depending on the number of attachment points. In general, it is contemplated that at least two quick release systems will be installed on at least two respective attachment points135on each barge115.

FIG. 5Ashows two barges115a,115bwith the topsides110loaded thereon with four attachment points on each barge, although the number can vary. In at least one embodiment, at least some of the attachment points on each barge can include at least one quick release system180and can include at least one actuator210. For example, the barge115acan include the attachment points135a′,135a″,135a″′,135a″″ (generally135) having quick release systems180a′,180a″,180a″′,180a″″ (generally180) with actuators210a′,210a″,210a″′,210a″″ (generally210) for the respective quick release systems at the respective attachment points. Similarly, the barge115bcan include the attachment points135b′,135b″,135b″′,135b″″ having quick release systems180b′,180b″,180b″′,180b″″ with actuators210b′,210b″,210b″′,210b″″ for the respective quick release systems at the respective attachment points. In at least one embodiment, the actuators can be operatively coupled to synchronize their release of their respective quick release systems. The operative coupling can occur electrically, such as through wiring or wirelessly, or mechanically, such as through linkages, hydraulically, pneumatically, and other means of coupling the operation with one or more other actuators.

FIG. 5Bis a top schematic view of a topsides loaded on two barges according to the invention with at least one alternative quick release system. The embodiment inFIG. 5Bshows an actuator controlling the release of multiple quick release systems. (For variation and ease of reference, only two attachment points are labeled, with the understanding that the number of actual attachment points can vary.) For example, an actuator210acan control the release of the quick release system180a′ at the attachment point135a′ and the quick release system180a″″ at the attachment point135a″″. Similarly, an actuator210bcan control the release of the quick release system180b′ at the attachment point135b′ and the quick release system180b″″ at the attachment point135b″″.

In at least one embodiment, the actuators210can control the respective releases by means of flexible links coupled to the respective quick release systems. The term “flexible link” is used broadly and includes cables, wire, rope, slings, chains, rods, and other linkages that can be pulled or pushed to cause a motion, and includes associated hardware such as clamps, fasteners, links, couplers, and the like. One or more pulleys can be used to guide a flexible link around turns. For example on barge115a, the actuator210acan be coupled to a flexible link212a′ around a pulley215a′ to be coupled to the quick release system180a′ at the attachment point135a′ of the grillage125a. The same actuator210acan also be coupled to a flexible link212a″″ around a pulley215a″″ to be coupled to the quick release system180a″″ at the attachment point135a″″ of the grillage125a. Thus, the actuator210acan actuate both quick release systems180a′ and180a″″. The actuation can occur in a synchronized matter, such as substantially simultaneously, so that the topsides is released evenly from the barge115a. A similar system can be used for the barge115bwith similar elements similarly labeled.

FIG. 5Cis a schematic end view of a quick release system coupled between the topsides and the grillage system.FIG. 5Dis a schematic side view of a quick release system ofFIG. 5C.FIG. 5Eis a schematic end view of the quick release system in a closed position, as an enlarged view fromFIG. 5C. The figures provide more details of the quick release system described in reference toFIGS. 5A-5B, and will be described in conjunction with each other.

In at least one embodiment, the quick release system180can be placed in tension to pull the topsides110into proximity and preferably into contact with the grillage system125. In the embodiment shown, for example, the quick release system180can pull the topsides110into compressive load contact with a grillage support plate140of the grillage system125to limit further vertical movement of the topsides relative to the grillage system.

In general, a portion181of the quick release system can be coupled between one of the topsides110or the grillage system125to a releasable element191, such as a releasable hook, as shown inFIGS. 5C-5E. Another portion183of the quick release system can be coupled to the other of the topsides or the grillage system. The releasable element191can be actuated to release at least one of the portions, so that the topsides can be released from the grillage system. The quick release system on one attachment point can be operatively coupled with one or more other quick release systems on one or more other attachment points whether on one barge or on both barges. When all quick release systems are synchronized, a virtually simultaneous release of the topsides from the grillage system can be accomplished as described in more detail below.

In at least one embodiment, the quick release system180can include a series of flexible links with associated connections that are coupled with the releasable element191. Using the exemplary orientation of components in the relevant Figures, an upper padeye182can be coupled to the topsides110in a position to allow attachment of the quick release system180on one end. A corresponding lower padeye184can couple to the grillage system125in a position to allow attachment of the quick release system180on the other end. Starting at the upper padeye182, a shackle186can be coupled between the padeye182and a quick release flexible link188. The quick release flexible link188can extend downward to a master link190that can be engaged with a releasable element191, such as a releasable hook192. The exemplary releasable hook192includes a rotatable portion193rotatably coupled through a hinge joint194to the remainder of the hook192. A commercially available example of a releasable hook is known as a “Pelican hook”, available from a variety of third party vendors. A latch196(also known as a bale) is rotatably coupled to the releasable hook192, through a hinge joint198and helps maintain the rotatable portion193in a latched position until ready for release. A connecting link200is coupled between the hook192(distal from the master link190) and a tension adjuster202, such as a turnbuckle. In at least one embodiment, the tension adjuster202can adjust the tension on the flexible link188and the hook192by adjusting an overall length of the quick release system180. In turn, the tension adjuster202can be coupled to a connecting link204, which can be coupled to a shackle206, and then to the lower padeye184, which is coupled to the grillage system125.

Further, an actuator210can be used to release the quick release system180. In at least one embodiment, the actuator can be a mechanical based actuator, such as a winch210. The winch210includes an actuator flexible link212that can be coupled to a flexible link214, which in turn is coupled to the latch196on the hook192through shackle218. Pulleys, such as a snatch block216, can be used for miscellaneous turns in direction for the flexible link212and/or flexible link214. The actuator, such as a winch, can be actuated electrically, hydraulically, pneumatically, or manually. If by powered actuation, a control system220can be used to control the actuation. For timing and possible synchronization with other actuators210at other attachment points135of the grillage system125, a communicator222can be used. The communicator222can be wired or wireless to communicate with other communicators and other control systems that are coupled with other quick release systems at other attachment points.

While the quick release system is described in terms of flexible links, such as wire slings or chains, and mechanical actuation, it is understood that operational variations are contemplated. For example, hydraulic, pneumatic, electrical linear movement or rotational movement can cause the quick release system to release. Further, rods can be used instead of wire slings, and removable bolts, clamps, latches, and the like can be used instead of a releasable hook to accomplish the quick release function of the quick release system.

FIG. 6Ais a schematic end view of the barges floating over an offshore platform, such as a Spar hull.FIG. 6Bis a schematic top view of a detail portion of the topsides fromFIG. 6Awith the sea fastening between grillage top and topsides removed.FIG. 6Cis a schematic top view of a detail portion of the topsides fromFIG. 6Awith the sea fastening between barge and pre-installed bracing member of the topsides removed. The figures will be described in conjunction with each other.

The next step is transferring the topsides to the offshore platform, such as a Spar hull. In general, a floating offshore platform165can be at least partially de-ballasted, such that weight of the topsides110can be gradually and safely transferred to supports at the top of the offshore platform. If the offshore platform165is a fixed offshore platform, then the barges can be ballasted. In either example, the relative elevations between the offshore platform and the barges (and the topsides on the barges) changes, so that the topsides engages and is at least partially supported by the offshore platform. The above procedures can be adapted with the use of a single barge to transfer the topsides to the offshore platform.

Once at least a partial weight of the topsides110is transferred from the barges115to the offshore platform165, the bracing members120between the topsides110and the barges115can be cut or the welds can be removed, for example at locations172, so that the bracing members are uncoupled, as shown inFIG. 6B. Other than gravity forces on any remaining weight on the grillage system125, the topsides110is vertically restrained with the grillage system at this time primarily by the quick release system180. After uncoupling the bracing members, the topsides110is still restrained laterally at the fork/locking plate locations on the barges115. Before transferring the load from the barges115to the hull of the offshore platform165, the locking plates132may be cut, for example at locations171, and any lashing lines can be detached to ultimately allow the barges to be pulled away from topsides, as shown inFIG. 6B.

FIG. 7is a schematic end view of the quick release system in a released position. After substantially all of the topsides weight is supported by the offshore platform, the actuator210(as shown inFIG. 5C) can pull the latch196to release the rotatable portion193of the hook192. The master link190and the quick release flexible link188are released. If other quick release systems on other attachment points are synchronized, the entire topsides previously connected to the grillage system at multiple attachment points can be released virtually simultaneously.

Once the topsides is released, a floating offshore platform165(as shown inFIG. 6A) can raise the topsides to vertically clear the guide pins131, or the barges115can be ballasted to lower the guide pins for clearance for a fixed offshore platform. When the barges115are free from the topsides110, the barges115can be pulled away from the offshore platform.

FIG. 8Ais a schematic end view of another embodiment of the quick release system in a closed position.FIG. 8Bis a schematic top view of the embodiment ofFIG. 8Ain the closed position.FIG. 8Cis a schematic end view of the embodiment ofFIG. 8Awith the quick release system in an open position.FIG. 8Dis a schematic top view of the embodiment ofFIG. 8Cin the open position. The figures will be described in conjunction with each other. The grillage system125can include a grillage seat142, and the topsides110can include a seating guide144to engage the grillage seat and limit the downward travel of the topsides relative to the grillage system. The grillage seat142can also have a lateral anchor plate226positioned below the seating guide144when engaged with the grillage seat. The quick release system180can include at least one flexible link and advantageously at least two flexible links188coupled between the topsides110and the grillage system125. The flexible links can have a rated tensile load failure strength after which the flexible link will break. For example, the flexible links can be coupled between a support structure138on the topsides110and the anchor plate226on the grillage system with one or more anchors228coupled to the flexible links through openings224formed therethrough for the flexible links. The flexible links can be designed to fail at a given rated tensile load.

In operation, the topsides could be transferred to the offshore structure, so that as the offshore structure progressively supports more of the topsides load and displaces the load away from the barges, the tensile force on the flexible links would increase. The increased force eventually would actuate the quick release system by breaking the flexible links188and allow the topsides to vertically uncouple from the grillage system125on the barges.

Advantageously, the flexible links188could be coupled to each other at a given attachment point, such in a loop or linearly, between the topsides and the grillage system. If either flexible link188breaks at the attachment point, then the quick release system180would be released and the topsides110could be vertically uncoupled from the grillage system125. This redundancy could assist in providing a more predictable release of the topsides for synchronization with other quick release systems180on other attachment points135between the topsides and grillage system.

FIG. 9Ais a schematic end view of another embodiment of the quick release system in a closed position.FIG. 9Bis a schematic top view of the embodiment ofFIG. 9Ain the closed position.FIG. 9Cis a schematic end view of the embodiment ofFIG. 9Awith the quick release system in an open position.FIG. 9Dis a schematic top view of the embodiment ofFIG. 9Cin the open position. The figures will be described in conjunction with each other. The embodiment is similar to the embodiment described in conjunction withFIGS. 8A-8D, but also includes a further quick release system of frangible elements, generally including frangible nuts, explosive bolts and nuts (also known as pyrotechnic fasteners), and other frangible fasteners that can be actuated to fail upon certain occurrences and in addition to the tensile loads on the flexible elements described above. For example, a pyrotechnic fastener is generally a fastener, usually a nut or bolt, that incorporates a pyrotechnic charge as an actuator that can be initiated remotely. One or more explosive charges embedded within the fastener can be typically actuated by an electric current, and the charge can break the fastener into two or more pieces. The fasteners are typically formed with weakened portions around their circumference at the point(s) where the severance should occur. In other embodiments, the frangible element can be shaped to fail at a given load and thus the load would function as the actuator. Frangible elements are commercially available, their activation is known, and it is believed to be unnecessary to describe in further detail.

The grillage system125can include a grillage seat142, and the topsides110can include a seating guide144to engage the grillage seat and limit the downward travel of the topsides relative to the grillage system. The grillage seat142can also have a lateral anchor plate226positioned below the seating guide144when engaged with the grillage seat. The quick release system180can include at least one flexible link and advantageously a plurality of flexible links188coupled between the topsides110and the grillage system125. For example, the flexible links can be coupled between a support structure138on the topsides110and the anchor plate226on the grillage system with one or more anchors228coupled to the flexible links through openings224formed therethrough for the flexible links. The flexible links can be designed to fail at a given rated tensile load.

The flexible links188could be coupled to each other, such in a loop or linearly, between the topsides and the grillage system. If either flexible link188breaks, then the quick release system180would be released and the topsides110could be vertically uncoupled from the grillage system125. This redundancy could assist in providing more predicable release of the topsides for synchronization with other quick release systems180on other attachment points135between the topsides and grillage system.

The embodiment can also include frangible elements230that can be coupled to the flexible links as another quick release system in addition to the flexible links. The frangible elements230can be actuated to fail, such as explode, at a certain time, pressure, load, or signal to release the flexible links. In at least one embodiment, the frangible elements can be used in addition to the flexible links to assist in assuring the actuation of the quick release system or systems and release of the topsides from the grillage system.

In operation, the topsides could be transferred to the offshore structure, so that the tensile force on the flexible links would increase as the offshore structure progressively supports more of the topsides load and displaces the load away from the barges. The increased force eventually would actuate the quick release system by breaking the flexible links188and allow the topsides to vertically uncouple from the grillage system125on the barges. The frangible elements could be actuated when the flexible links are designed to fail to assist in assuring that one or more of the quick release systems function at the intended occurrence. Alternatively, the flexible links could be designed to fail (and therefore actuated) after the frangible elements are actuated, so that the flexible links provide a secondary backup system to the frangible elements. Further, the frangible elements could be actuated after the flexible links are designed to fail, so that the frangible elements provide a secondary backup system to the flexible links.

Thus, at least some embodiments can have multiple quick release systems at a given attachment point, such as those described above, various combinations of quick release systems described herein, and others. Such multiple quick release systems can assist in assuring the timely release of at least one quick release system and the synchronization of quick release systems at multiple attachment points.

In another embodiment by a variation of the embodiments inFIGS. 8A-8DandFIGS. 9A-9D, the frangible element could be used in lieu of the flexible link and coupled directly between the topsides and grillage system. so that actuation of the frangible element would directly release the quick release system and therefore the topsides from the grillage system. Given the descriptions provided herein, it is believed that no further description of this embodiment is required.

Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of Applicant's invention. Further, the various methods and embodiments of the catamaran system can be included in combination with each other to produce variations of the disclosed methods and embodiments. Still further, the concepts of the quick release system explained here within the exemplary context of a catamaran system can be used with a single barge supporting a topsides thereon, and therefore the invention is not limited to the embodiments herein or the catamaran exemplary application of the quick release system herein. Discussion of singular elements can include plural elements and vice-versa. References to at least one item followed by a reference to the item may include one or more items. Also, various aspects of the embodiments could be used in conjunction with each other to accomplish the understood goals of the disclosure. Unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising,” should be understood to imply the inclusion of at least the stated element or step or group of elements or steps or equivalents thereof, and not the exclusion of a greater numerical quantity or any other element or step or group of elements or steps or equivalents thereof. The device or system may be used in a number of directions and orientations. The term “coupled,” “coupling,” “coupler,” and like terms are used broadly herein and may include any method or device for securing, binding, bonding, fastening, attaching, joining, inserting therein, forming thereon or therein, communicating, or otherwise associating, for example, mechanically, magnetically, electrically, chemically, directly or indirectly with intermediate elements, one or more pieces of members together and may further include without limitation integrally forming one functional member with another in a unity fashion. The coupling may occur in any direction, including rotationally.