Abstract:
A floating support that can be joined with a floating platform while the floating platform is at a deployment location is disclosed. The support provides functionality to the floating platform in order to change, augment, upgrade, or diversify the platform&#39;s overall capability. In some embodiments, the present invention eases the serviceability of the platform by enabling a first support that has diminished capability to be readily replaced by a second support having superior capability—without removing the floating platform from its deployment location. In some embodiments, the present invention enables platform operation that is analogous to “plug and play” electronics systems. Further, in some embodiments, hydrodynamic performance of the floating platform can be changed with the addition or removal of one or more floating supports.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This case claims priority of U.S. Provisional Patent Application 61/145,467, which was filed on Jan. 16, 2009, and which is incorporated herein by reference. 
     In addition, the underlying concepts, but not necessarily the language, of the following cases are incorporated by reference:
         (1) U.S. patent application Ser. No. 61/225,991, filed Jul. 16, 2009;   (2) U.S. patent application Ser. No. 61/628,594, filed Dec. 1, 2009;   (3) U.S. patent application Ser. No. 61/573,982, filed Oct. 6, 2009; and   (4) U.S. Pat. No. 6,503,023, which issued Jan. 7, 2003.
 
If there are any contradictions or inconsistencies in language between this application and one or more of the cases that have been incorporated by reference that might affect the interpretation of the claims in this case, the claims in this case should be interpreted to be consistent with the language in this case.
       

    
    
     FIELD OF THE INVENTION 
     The present invention relates to off-shore installations in general, and, more particularly, to floating platforms. 
     BACKGROUND OF THE INVENTION 
     Offshore platforms are used to house workers and support production equipment at sites located in a large body of water. They are used in such applications as petroleum drilling and production, Ocean Thermal Energy Conversion (OTEC), and remote radar installations. Depending on the circumstances, an offshore platform might be fixed to the ocean floor, built on an artificial island, or floating at the surface of the body of water. 
     For deep-water applications, floating platforms, such as spars and semi-submersible platforms are typically used. Such floating platforms are subject to motion due to dynamic wave and wind forces. Platform motion can cause unacceptable stresses in riser and mooring lines and, in some cases, can curtail deck operations for extended periods of time. 
     Platform motion is particularly problematic for petroleum drilling and OTEC applications. In petroleum drilling applications, for example, platform motions must be kept small because many of these platforms comprise riser pipes that are rigidly fixed to the sea bed and attached to the platform. Typical OTEC systems normally include large diameter cold water pipes, which are suspended from their platforms and hang down to cold deep water regions. These cold water pipes can have lengths of 1000 meters or more. Excessive platform motion induces severe strains in these cold water pipes, which can lead to system failure. 
     In order to increase the reliability and lifetime of floating platform installations, a number of methods for reducing motion of a floating offshore platform have been developed in the prior art. These include:
         i. Providing a small waterplane area to reduce the wave loadings at the free surface;   ii. providing a deep draft to establish the keel of the body to be below the area of the highest wave energy, and to achieve a low center of gravity;   iii. using vertically rigid moorings; and   iv. providing hydrodynamic optimization, such as using wave force cancellation between the columns and pontoons of a semi-submersible platform.       

     These methods, however, increase the cost and complexity of the floating platforms. 
     A Spar platform is based upon a large-diameter, single or multiple vertical cylinder(s) that supports a deck above the surface of the water. About 90% of a typical spar structure is underwater. The cylinder is analogous to a deep-draft floating caisson, which is a hollow cylindrical structure similar to a very large buoy. A distinguishing feature of a spar is its deep-draft hull, which produces very favorable motion characteristics compared to many other floating concepts. 
     Due to its deep draft, a typical spar is deployed by floating it horizontally in a harbor or quay, towing it to a deployment site, and then upending it into a vertical orientation. Once oriented vertically, a derrick barge is used to lift a deck structure into place. This process is extremely expensive and time consuming. 
     Semi-submersible platforms are platforms configured with large buoyant pontoon structures that float below the water surface. Structural columns, attached to the pontoons pass through the water surface to support a platform deck at a significant height above the sea surface. Semi-submersible platforms can be anchored to the ocean floor or kept in position by attached thrusters. 
     The draft of some semi-submersible platforms can be transformed from a deep-draft to a shallow-draft by removing ballast water from its hull. A shallow-draft platform is analogous to a surface vessel and can be towed from a harbor or quay to its deployment location by a tugboat. Once at its intended location, ballast water is added to back into the hull to return the platform to a deep-draft configuration. 
     With its hull structure submerged at a deep draft, the semi-submersible platform is analogous to a spar and is less affected by wave loadings than a normal ship. Since a typical semi-submersible platform has a small water-plane area, however, it is sensitive to load changes on its deck. As a result, careful trimming is necessary to maintain platform stability. 
     In addition, a conventional spar or semi-submersible is designed to satisfy a single, rigid set of operational requirements expected throughout its operational lifetime. As a result, the amount of buoyancy and deck space made available for equipment and personnel are pre-determined based upon several factors: the environmental characteristics of its intended deployment location; the intended application of the platform; and its desired production capacity. 
     Once a conventional floating platform has been deployed at its deployment location, the flexibility of a floating platform is limited by the pre-determined design. In order to increase production capacity (e.g., increase drilling depth, modify the deck for additional equipment, add additional energy conversion equipment, change the configuration of equipment, etc.), the platform must be transported to a drydock, where the additional equipment and additional buoyancy (if necessary) can be conveniently added. In addition to the large expense such an operation incurs, the platform is also removed from service during the period of transportation and refit. 
     SUMMARY OF THE INVENTION 
     The present invention enables one or more characteristics of a floating platform to be changed while the platform remains at its deployment location. The present invention is suitable for use with any suitable floating platform, such as semi-submersible platforms or spars. The present invention is particularly well-suited to off-shore petroleum drilling platforms, OTEC platforms, off-shore windmill farms, and ocean-based radar installations. In some embodiments, the present invention enables alteration and/or repair of on-board systems of a floating platform. 
     In some embodiments, the present invention comprises a detachable floating column (i.e., support) that can be transported to a previously deployed off-shore platform. Once at the deployment location of the platform, the support is properly oriented and physically joined with the platform. In some embodiments, the addition of one or more supports to a platform enables:
         i. an increase in the payload capability of the platform; or   ii. increased stability of the platform; or   iii. increased deck area; or   iv. shallower draft of the platform; or   v. improved dynamic characteristics of the platform; or   vi. improved ability to survive a localized environment; or   vii. augmented, changed, or expanded functionality of the platform; or   viii. refurbishment and/or refitting of production equipment at the deployment location; or   ix. any combination of i, ii, iii, iv, v, vi, vii, and viii.       

     In some embodiments, a support comprises significant deck space to enable an increase in the available working area of a platform after the support has been mounted to it. In some embodiments, the support supports the addition of an additional deck module to increase the available working area of the platform. 
     In some embodiments, a support comprises one or more storage areas that enable the support to contain equipment such as production systems or sub-systems (e.g., heat exchangers, pump systems, etc.) that augment, redefine, or expand the production capability of the platform. 
     In some embodiments, a support comprises one or more integrated heat exchangers. As a result, heat exchanger capacity and/or electrical generation capability of a deployed platform can be augmented by the addition of one or more of such supports. Further, the use of such supports facilitates maintenance of heat exchangers located at the platform by enabling a problematic heat exchanger to be replaced by a new or refurbished heat exchanger without removing the platform from service. This reduces the amount of operational capability lost due to preventive maintenance, disaster recovery, and/or failure recovery. 
     In some embodiments, a support enables improved stability of a platform so that the platform is less susceptible to local wind, wave, and storm conditions. As a result, OTEC platforms that comprise a long, suspended cold-water pipe can have improved reliability. 
     An embodiment of the present invention comprises: a method comprising (1) providing a platform module at a deployment location in a body of water, wherein the platform module is characterized by a first hydrodynamic performance, and wherein the platform module is hydrodynamically stable at the deployment location; (2) conveying a first support from a first location to the deployment location, wherein the first support is characterized by a second hydrodynamic performance, and wherein the first support comprises a first system having a first functionality; and (3) physically joining the first support and the platform module while the first support and the platform module are at the deployment location, wherein the first support and the platform module are physically joined at a first mounting position on the platform module; wherein the physically joined first support and platform module are collectively characterized by a third hydrodynamic performance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a schematic drawing of a semi-submersible platform in accordance with the prior art. 
         FIG. 2  depicts a schematic diagram of a Tension Leg Platform (TLP) oil production platform in accordance with the prior art. 
         FIG. 3  depicts a TLP platform during installation in accordance with the prior art. 
         FIG. 4  depicts a schematic diagram of a semi-submersible OTEC platform in accordance with an illustrative embodiment of the present invention. 
         FIG. 5  depicts operations of a method suitable for adding functionality to a floating platform in accordance with the illustrative embodiment of the present invention. 
         FIG. 6  depicts a schematic drawing of a support in accordance with the illustrative embodiment of the present invention. 
         FIG. 7  depicts a schematic diagram of a mounting system in accordance with the illustrative embodiment of the present invention. 
         FIG. 8  depicts operations of a method suitable for refurbishing a floating platform in accordance with the illustrative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following terms are defined for use in this Specification, including the appended claims:
         Physically joined is defined as meaning substantially rigidly connected. Two objects might be physically joined in direct contact with one another, or through an intermediary element, such as a mounting system.   Deployment location is defined as the deep-water position in a body of water at which a semi-submersible platform is stationed for operation. Deployment location does not include quayside locations or harbors, such as those normally used for the construction of a semi-submersible platform. For example, a conventional semi-submersible platform is typically assembled in a harbor or at quayside and then towed to its deployment location where it is put into operation.       

       FIG. 1  depicts a schematic drawing of a semi-submersible platform in accordance with the prior art. Platform  100  comprises deck  102 , submerged structure  112 , OTEC system  108 , cold-water conduit  126 , mooring lines  116 , and anchors  118 . Platform  100  is configured for use in an OTEC application. 
     Deck  102  is a platform for supporting OTEC system  108  and heat exchangers  130  and  136 , as well as operational personnel and their quarters. Deck  102  is supported above the surface of the water by submerged structure  112 . Deck  102  has a fixed work area since the size of deck  102  is determined at platform design. 
     Submerged structure  112  comprises columns  104  and frames  106 . Submerged structure  112  and deck  102  collectively define platform module  140 . 
     Each of columns  104  is a vertical column that has a buoyancy and water plane area suitable for supporting deck  102  above the surface of the water. Columns  104  are held in place by frame  106 . In some cases, frame  106  comprises pontoons that augment the buoyancy of columns  104 . 
     OTEC system  108  comprises heat exchangers  130  and  136 , closed-loop conduit  138 , and turbogenerator  140 . OTEC system  108  is a Rankine engine that generates electrical energy based on the temperature differential between water from surface region  132  and water from deep-water region  128 . The generated electrical energy is provided on output cable  110 . Turbogenerator  140  is driven by a working fluid (e.g., ammonia, etc.) in close-loop conduit  138 , which is vaporized at heat exchanger  136 . The working fluid is vaporized by its thermal coupling with warm water from surface region  132  that is pumped through heat exchanger  136  via conduit  134 . After passing through turbogenerator  140 , the working fluid is condensed back into liquid form at heat exchanger  130 , where it is thermally coupled with cold water conveyed from deep-water region  128  by conduit  126 . After passing through heat exchanger  130 , the cold water is typically ejected by conduit  126  into a mid-level region of ocean  122  to avoid significantly cooling the water in surface region  132 . 
     Cold-water conduit  126  is a long conduit suitable for conveying cold water up to deck  102  from deep-water region  128 . Typically, cold-water conduit  126  has a length of 1000-2000 meters. As a result, conduit  126  is susceptible to damage caused by lateral motion of platform  100 . 
     To avoid significant motion of platform  100 , it is held in position, laterally and vertically, at deployment location  124  by a mooring system that comprises mooring lines  116  that are attached to anchors  118 , which are anchored to ocean floor  120  of ocean  122 . Anchors  118  are located outside the perimeter of deck  102  so that they provide horizontal stabilization. 
     The characteristics of deck  102 , submerged structure  112 , and the mooring system, such as draft, payload, deck area, water plane area, mooring line tension, and the like, collectively determine the hydrodynamic behavior of platform  100 . These factors are determined at platform design and are based upon environmental conditions at deployment location  124  and the intended application of platform  100 . These environmental conditions are geographically based as well as water-depth based and include, for example, storm history, underwater currents, wind conditions, wave height, wavelengths, water temperature, and the like. 
       FIG. 2  depicts a schematic diagram of a Tension Leg Platform (TLP) oil production platform in accordance with the prior art. Platform  200  comprises deck  102 , hull  202 , tension legs  204 , production risers  206 , piles  208 , production system  212 , and export pipeline  214 . 
     Hull  202  is a partially buoyant structure that supports deck  102 . In similar fashion to platform  100 , hull  202  comprises buoyant columns  104 , which are held in place by frame  106 . In some cases, frame  106  comprises pontoons that augment the buoyancy of columns  104 . 
     Deck  102  and hull  202  collectively define platform module  210 . 
     Tension legs  204  are stiff structural members that secure deck  102  and hull  202  to ocean floor  120 . Tension legs  204  are commonly steel pipes of sufficient size and strength to withstand strains due to wave action and the like. Tension legs  204  are attached between hull  202  and piles  208 . In some cases, tension legs  204  are vertically oriented mooring lines that are connected to anchors located at ocean floor  120 . 
     Piles  208  are typically concrete or steel piles driven into ocean floor  120  by means of a hydraulic hammer. 
     Production risers  206  are conduits for conveying petroleum products from reservoirs (not shown) under the seabed to deck  102 . 
     Tension legs  204  and piles  208  collectively define a mooring system that maintains platform  200  at deployment location  124 . Tension legs  204  are held in tension by the buoyancy of hull  202 . This dampens vertical motions of platform  200 , but allows horizontal movement due to wind, waves and current. In order to limit horizontal movement, tension legs  204  are typically pre-tensioned to a high value. This increases the amount of buoyancy required for a TLP compared to a comparable semi-submersible platform, such as platform  100 . 
     Production system  212  typically includes oil drilling rigs, pumps, etc. that are necessary to extract petroleum products from production risers  206  and deliver them to a storage facility via export pipeline  214 . 
       FIG. 3  depicts a TLP platform during installation in accordance with the prior art. Once platform  300  is fully assembled, it is analogous to platform  200  and comprises floating structure  210  and tension legs  204 . In  FIG. 3 , however, platform  300  is depicted prior to installation of tension legs  204  at deployment location  124  and, therefore, comprises only floating structure  210 . 
     Some TLP platforms are unstable prior to the attachment of its tension legs. As a result, a TLP platform in this condition is likely to capsize and assume an upside down orientation. Once the TLP platform is moored by tendons or tension legs, however, the structure becomes stable. 
     As a result, temporary stability modules (TSMs)  302  have been utilized in the prior art to temporarily stabilize floating structure  210 . TSMs are disclosed, for example, by E. Huang, et al., in U.S. Pat. No. 6,503,023, which issued Jan. 7, 2003, which is included by reference herein. Each of TSMs  302  is a substantially hollow rectangle made of a semi-solid material (e.g., foam). In some cases, TSMs  302  comprise inflatable bags commonly used in offshore salvage operations. 
     By outfitting it with one or more TSMs  302 , the stability of floating platform  210  is improved to enable its assembly in a shallow harbor or quayside and subsequent towing to deployment location  124 . Once tension legs are attached at the deployment location, TSMs  302  are removed from platform  300 . 
     It should be noted that, since the TSMs  302  are intended only for short-term use at the deployment location, they are constructed of materials that are insufficient for withstanding the environmental conditions at deployment location  124  for long periods of time. For example, Huang discloses that “Because the TSM is a temporary device, which is removed after the platform is installed, less stringent design and material requirements are imposed, which lowers the cost of the device.” Huang provides TSMs as substantially hollow watertight containers made of combinations of metals, plastics, and/or composites, inflatable bags, or low-density or semi-solid materials, such as foams. Although this inexpensive construction methodology reduces the cost and complexity of TSMs  302 , such construction limits their use to only temporary deployment applications. 
       FIG. 4  depicts a schematic diagram of a semi-submersible OTEC platform in accordance with an illustrative embodiment of the present invention. Platform  400  platform module  140 , mooring lines  116 , anchors  118 , supports  402 - 1  and  402 - 2 , mounting systems  404 , and OTEC system  406 . 
       FIG. 5  depicts operations of a method suitable for adding functionality to a floating platform in accordance with the illustrative embodiment of the present invention. Method  500  is described herein with continuing reference to  FIG. 4  and additional reference to  FIGS. 6 and 7 . 
     Method  500  begins with operation  501 , wherein platform module  140  is provided at deployment location  124 . Typically platform module  140  is built at a construction site near a shore installation, such as in a shallow-draft harbor or quayside location. Platform module  140  is characterized by a first hydrodynamic performance that facilitates its construction and commissioning in a shallow-water environment. For example its hydrodynamic performance is typically suitable for quayside installation and commissioning of topside deck equipment, as well as facilitating the towing of platform module  140  from the shallow-water location to deployment location  124  in an upright configuration. Once positioned at deployment location  124 , mooring lines  116  are attached between platform module  140  and anchors  118  to hold the platform in position and provide horizontal restraint. 
     At operation  502 , supports  402 - 1  and  402 - 2  (collectively referred to as supports  402 ) are conveyed from a construction location to deployment location  124 . Typically, supports  402  float horizontally on the surface of ocean  122  and are towed to deployment location  124 . In some embodiments, supports  402  are transported to deployment location  124  on a barge or other vessel. Although the illustrative embodiment comprises two supports  402 , it will be clear to one skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention that comprise any practical number of supports  402 , such as one support  402  or more than two supports  402 . 
       FIG. 6  depicts a schematic drawing of a support in accordance with the illustrative embodiment of the present invention. Support  402  comprises shell  602 , cover  604 , ballast chamber  606 , heat exchanger  408 , pump  608 , conduits  416 , bulkheads  610 , and mounting bracket  622 . 
     Shell  602  is a substantially cylindrical sleeve made of a steel or other metal suitable for use in ship building. The cylindrical sleeve may be circular, rectangular, square or other suitable cross section for the purposes of fitting necessary components. Preferably, the material used for shell  602  is suitable for extended operation in the environment of deployment location  124 . One skilled in the art will recognize that in some embodiments, shell  602  comprises a plurality of sections that are joined using appropriate joining technology. In some embodiments, stiffeners, girders and frames are included to provide sufficient strength against the pressure of the sea and loads imposed by waves, internal weight, and buoyancy. 
     Cover  604  and bulkheads  610  separate shell  602  into a plurality of substantially watertight compartments. In addition, bulkheads  610  provide additional mechanical strength to support  402 . 
     At operation  503 , each of supports  402 - 1  and  402 - 2  is rotated into a substantially vertical orientation by flooding ballast chamber  606 . Once oriented properly, each of supports  402  is attached to platform module  140  at a mounting system  404 . 
       FIG. 7  depicts a schematic diagram of a mounting system in accordance with the illustrative embodiment of the present invention. Mounting system  404  comprises plate  702 , mating pins  704 , straps  706  and  708 , and latch  710 . 
     Plate  702  is a rigid plate that is attached to column  104 . 
     Mating pins  704  project outward from seat  706  and are dimensioned and arranged to be received by complimentary holes  624  of mounting bracket  622 . As a result, mating pins  704  locate a support  402  in seat  706 . 
     Once support  402  is positively located by mating pins  704 , straps  706  and  708  are wrapped around support  402  and detachably secured by latch  710 . In order to secure latch  710 , base  714  is engaged with cam  712 . 
     The desired hydrodynamic performance of platform  400  is determined based on the environmental conditions at deployment location  124 , including storm history, underwater currents, wind conditions, wave height, wavelengths, water temperature, and the like. The hydrodynamic performance of platform  400  is based on the buoyancy characteristics of the platform, its draft, and its water plane area. The water plane area of the platform affects its ability to withstand disturbances due to wave action, wind, etc. In some embodiments, the addition of supports  402  to platform module  140  changes the hydrodynamic performance of platform  400  by:
         i. changing its buoyancy characteristics; or   ii. changing its draft; or   iii. changing its water plane area; or   iv. changing its moment of inertia; or   v. changing its stability; or   vi. any combination of i, ii, iii, iv, and v.       

     At operation  504 , heat exchangers  408 - 1  and  408 - 2  are fluidically coupled with OTEC system  406 , which is analogous to OTEC system  108 , described above and with respect to  FIG. 1 . 
     Heat exchangers  408 - 1  and  408 - 2  are heat exchangers suitable for use in OTEC applications. Examples of heat exchangers suitable for use in support  402  are described in U.S. patent application Ser. No. 61/225,991, filed Jul. 16, 2009, U.S. patent application Ser. No. 61/624,594, filed Dec. 1, 2009, and U.S. patent application Ser. No. 61/573,982, filed Oct. 6, 2009, each of which is incorporated herein by reference. 
     Heat exchangers  408 - 1  and  408 - 2  and OTEC system  406  are fluidically coupled by connecting external conduits  410 - 1  and  410 - 2 , respectively, to conduit  414  through fittings  412 . Conduits  414 ,  416 - 1 , and  416 - 2  are conventional conduits suitable for conveying working fluid, such as ammonia, through OTEC system  406 . Fluidically coupled conduits  414 ,  416 - 1 , and  416 - 2  collectively define a closed-loop conduit that is analogous to closed-loop conduit  138  described above and with respect to  FIG. 1 . 
     Pump  608  comprises motor  612  and impeller  614 . Motor  612  is housed within chamber  616 , which substantially protects the motor from exposure to seawater. 
     In evaporator operation, such as that depicted for support  402 - 1 , pump  608  draws warm seawater from surface region  132  into port  620  and drives the warm seawater through heat exchanger  408 . After passing through heat exchanger  408 , the seawater is ejected back into ocean  122  through port  618 . The pathway between ports  618  and  620  is represented as conduit  418  in  FIG. 4 . At heat exchanger  408 , working fluid flowing through internal conduit  416  is thermally coupled with the warm seawater and vaporized. The vaporized working fluid expands and drives turbogenerator  114 . Turbogenerator  114  generates electrical energy and provides it on output cable  110 . In some embodiments, port  620  is fluidically coupled to a warm water conduit at fitting  420  to enable warm seawater from a shallower depth to be drawn into port  620 . In some embodiments, support  402  comprises a pump for pumping working fluid through conduits  414 ,  416 - 1 , and  416 - 2 . 
     In condenser operation, such as that depicted for support  402 - 2 , port  620  is fluidically coupled with cold-water conduit  126  at fitting  420 . Pump  608  draws cold seawater from deep-water region  128  into port  618  and drives the cold seawater through heat exchanger  408 . After passing through heat exchanger  408 , the seawater is ejected back into ocean  122  through port  618 . At heat exchanger  408 , vaporized working fluid from turbogenerator  114  is thermally coupled with the cold seawater and condenses back into liquid form. 
     In some embodiments, support  402  comprises more than one heat exchanger and associated conduits. In addition, in some embodiments, support  402  comprises systems that are other than heat exchangers, such as pumps, electrical systems, communications equipment, cranes, storage space, housing facilities, etc. In some embodiments, a single support can include:
         i. multiple evaporators; or   ii. multiple condensers; or   iii. evaporators and condensers; or   iv. one or more systems other than a heat exchanger; or   v. any combination of i, ii, ii, and iv.       

     The inclusion of heat exchangers (and/or other systems) affords embodiments of the present invention several advantages over conventional floating platforms. 
     First, production capacity of an OTEC platform can be changed by adding or removing supports. For example, the electrical generation capability of a floating platform in accordance with the present invention can grow with increasing energy demand by adding additional supports as necessary throughout the lifetime of the platform. As a result, a platform need not be deployed with excess capability in anticipation of future energy demands. 
     Second, the present invention makes it easier to service a floating platform when necessary. Heat exchangers are prone to bio-fouling, damage, etc. It is difficult, however, to service a heat exchanger at a deployment location. In addition, the time required to service a heat exchanger on-site reduces the uptime and overall efficiency of the OTEC platform. The present invention enables a support comprising a mechanical system, such as a heat exchanger, to be rapidly replaced with another such support. As a result, downtime for the platform is reduced and the damaged heat exchanger can be easily transported back to a shore installation for service. 
     Third, new functionality can be added to a floating platform simply by attaching a support that comprises a suitable system. 
     Fourth, the load capacity of a floating platform can be increased by attaching additional deck modules without removing the floating platform from deployment location  124 . For a conventional floating platform, increasing deck size is difficult, if not impossible, since the hydrodynamic performance of the platform is determined at design. By attaching additional supports in accordance with the present invention, the hydrodynamic performance of a floating platform can be changed, on-site, to accommodate additional deck area. 
     Although support  402  comprises a heat exchanger that is located within shell  602 , it will be clear to one skilled in the art, after reading this specification, how to specify, make, and use alternative embodiments of the present invention wherein a support comprises a system that is mounted to an external surface of shell  602 . 
       FIG. 8  depicts operations of a method suitable for refurbishing a floating platform in accordance with the illustrative embodiment of the present invention. Method  800  is described herein with reference to  FIGS. 4 ,  6 , and  7 . Method  800  begins with operation  801 , wherein a replacement support (e.g., a support  402 - 3 ) is conveyed to location  124 . 
     At operation  802 , external conduits  410 - 1  are disconnected from conduits  416 - 1  at fitting  412  to fluidically decouple heat exchanger  408 - 1  and OTEC system  406 . 
     At operation  803 , support  402 - 1  is removed from platform module  140  by disengaging mounting system  404 . Ballast chamber  606  is then vented with air to empty it of seawater, which induces support  402 - 1  to float horizontally on the surface of ocean  122  to facilitate its transport to a repair facility. 
     At operation  804 , support  402 - 3  (which is substantially identical to support  402 - 1 ) is rotated from a horizontal orientation on the surface of ocean  122  into a substantially vertical orientation by flooding its ballast chamber  606 . Support  402 - 3  and platform module are physically joined by seating support  402 - 3  in mounting system  404  and securing straps  706  and  708  with latch  710 . 
     At operation  805 , external conduits  410 - 1  are fluidically coupled with conduits  416 - 3  at fitting  412  to fluidically couple heat exchanger  408 - 3  and OTEC system  406 . 
     At the completion of operation  805 , platform  400  is again operational. 
     It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims.