Joint for attaching cold water pipe to floating vessel, and method thereof

Abstract

A joint 100 for attaching a cold water pipe to a floating vessel comprises a plurality of concentrically nested annular portions. An innermost annular portion 110 defines a through bore 115 for receiv

Description

The present disclosure relates to the field of ocean thermal energy conversion (OTEC) systems, and specifically to a joint, a cold water riser assembly comprising the said joint, and a method of installing a cold water riser assembly on a floating vessel. BACKGROUND Ocean Thermal Energy Conversion (OTEC) is a renewable energy technology that harnesses the temperature difference between warm surface seawater and cold deep water to generate electricity. This technology has significant potential for application across the tropics, where warm surface water and cold deep water are readily available. The basic principle of OTEC involves pumping warm surface seawater and cold deep water into a heat engine cycle. The temperature difference between the warm water and cold water is utilized to drive a heat engine, such as a Rankine cycle or a closed-cycle ammonia system, which in turn generates electricity. OTEC offers the advantage of being a continuous and sustainable source of power, as the temperature difference between surface and deep water is relatively constant. However, one of the technical challenges in implementing OTEC systems is the method of bringing the cold water from the bottom of the ocean onto barge or platform where the power generation equipment is located. This cold water connection is critical for the efficient operation of the OTEC system, and its successful implementation is essential to make OTEC economically viable. The cold water connection faces several significant challenges that need to be addressed. For instance, the connection needs to be able to withstand high flow rates of cold water from the depths of the ocean. Also, the connection needs to accommodate multiple degrees of freedom, allowing for rotational and horizontal movement of the barge or platform in response to oceanic conditions, like varying rotational and horizontal loading caused by waves, currents, and tidal forces. Further, the connection needs to maintain a long fatigue life to ensure its durability and reliability over an extended period of operation. Without a reliable and robust cold water connection, the OTEC system becomes unviable as the service life of the connection is insufficient to provide a desirable levelized cost of electricity (LCOE). Solving the technical challenges associated with the cold water connection in OTEC systems would unlock the potential to provide baseload power to over 600,000,000 people living in the tropical regions. Many of these island nations heavily rely on fossil fuels for their energy needs, resulting in high energy costs, environmental degradation, and vulnerability to fluctuations in fuel prices. OTEC represents a promising pathway for these island nations to reduce their dependence on fossil fuels and transition towards a clean and sustainable energy future. Moreover, OTEC offers an advantage over traditional renewable energy systems by minimizing the significant land requirements associated with solar or wind power installations, making it particularly suitable for island communities with limited land resources. Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned limitations / drawbacks. SUMMARY The aim of the present disclosure is to provide a joint, a cold water riser assembly comprising the said joint, and a method of installing a cold water riser assembly on a floating vessel, that provide an improved cold water connection in OTEC systems to overcome the discussed technical challenges and enable the widespread adoption of this renewable energy technology. The present disclosure aims to address these challenges and provide an innovative solution that ensures the efficient and reliable extraction of cold water for power generation, making OTEC economically viable and environmentally sustainable. The aim of the present disclosure is achieved by a joint, a cold water riser assembly comprising the said joint, and a method of installing a cold water riser assembly on a floating vessel as defined in the appended independent claims to which reference is made to. Advantageous features are set out in the appended dependent claims. Throughout the description and claims of this specification, the words "comprise", "include", "have", and "contain" and variations of these words, for example "comprising" and "comprises", mean "including but not limited to", and do not exclude other components, items, integers or steps not explicitly disclosed also to be present. Moreover, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic illustration of a joint, in accordance with one or more embodiments of the present disclosure; FIG. 2 is a diagrammatic illustration of a joint, in accordance with one or more embodiments of the present disclosure; FIG. 3 is a diagrammatic illustration of a joint, in accordance with one or more embodiments of the present disclosure; FIG. 4 is a sectioned illustration of a joint, in accordance with one or more embodiments of the present disclosure; FIG. 5 is a diagrammatic illustration of a joint with tapered collar therein, in accordance with one or more embodiments of the present disclosure; FIG. 6 is a diagrammatic illustration of a joint depicting details of the tapered collar therein, in accordance with one or more embodiments of the present disclosure; FIG. 7 is a diagrammatic illustration of components of the tapered collar, in accordance with one or more embodiments of the present disclosure; FIG. 8 is a sectioned illustration of a cold water riser assembly with a cold water pipe, in accordance with one or more embodiments of the present disclosure; and FIG. 9 is an illustration of a flowchart listing steps involved in a method of installing a cold water riser assembly on a floating vessel, in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF EMBODIMENTS The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practising the present disclosure are also possible. In a first aspect, the present disclosure provides a joint for attaching a cold water pipe to a floating vessel, the joint comprising a plurality of concentrically nested annular portions, including an innermost annular portion defining a through bore for receiving an end of the cold water pipe, and an outermost annular portion configured for attachment to the vessel, wherein each annular portion is slidably engaged with a concave wall of the concentrically next outer annular portion to allow multidirectional movement of the annular portions independently with respect to one another. The joint is designed for attaching a cold water pipe to a floating vessel in the context of an Ocean Thermal Energy Conversion (OTEC) system. The joint is intended to address the technical challenges associated with the connection of the cold water pipe to the floating vessel, ensuring its durability, flexibility, and multidirectional movement capabilities. The sliding engagement between the concentrically nested annular portions allows for multidirectional movement of the joint. Further, the stacked configuration of the annular portions provides enhanced range of motion to the joint. These features provides flexibility to the joint to accommodate rotational and horizontal movements of the vessel caused by waves, currents, and tidal forces, and contribute to its overall robustness and longevity. In a second aspect, the present disclosure provides a cold water riser assembly comprising a joint according to the said first aspect and a cold water pipe. The cold water riser assembly provides an efficient and reliable procedure of connecting the cold water pipe to the joint while maintaining a secure interface between the two components. In a third aspect, the present disclosure provides a method of installing a cold water riser assembly on a floating vessel, the method comprising: - installing on the vessel a joint according to claim 3 including an innermost annular portion defining a tapered through bore; - transporting the vessel to an installation location; - transporting a cold water pipe to the installation location; - attaching a retrieval line to an end of the cold water pipe; - flooding the cold water pipe with water to sink the cold water pipe; - pulling the retrieval line to pull the end of the cold water pipe up through the tapered through bore; - installing a tapered collar around the end of the cold water pipe; and - lowering the end of the cold water pipe so that the tapered collar sits within the tapered through bore. The method provides a systematic approach to ensure the proper installation and secure attachment of the cold water pipe to the joint on the vessel. By following the present method, the cold water riser assembly may be installed effectively and securely on the floating vessel. The steps of attaching the retrieval line, flooding the pipe, pulling the line to lift the pipe, installing the tapered collar, and lowering the pipe ensure a controlled installation process, minimizing the risk of damage to the pipe or joint. The result is a robust and reliable connection between the cold water pipe and the joint, enabling efficient cold water extraction for the operation of the OTEC system. The joint, as proposed in the present disclosure, is designed to be implemented as an integral component of, for example, an offshore OTEC system, and serves a critical function in attaching a cold water pipe to a floating vessel such as an OTEC barge. The joint exhibits a versatility that could extend its applicability to other offshore use cases requiring dependable and resilient connections due to its robust design, the ability to handle multi-directional movement, and the inherent durability. For example, the joint may be used with drill strings in offshore drilling operations which are subjected to substantial stresses due to their operational nature and the demanding oceanic environment. The joint, with gimbal arrangement and its nested annular portions and fluid-actuated pistons, can reduce stresses on the drill strings, while the fluid-actuated pistons can dampen the motions, similar to their function in the OTEC system. Additionally, the joint may be employed in Liquified Natural Gas (LNG) cooling systems which often operate under high pressures and in harsh environmental conditions. The ability of the joint to handle high flow rates and multidirectional movements, because of the nested annular portions and fluid-actuated pistons, may enhance the operational reliability of these LNG cooling systems. The joint incorporates a gimbal mechanism in the form of the plurality of concentrically nested annular portions. The concentric nesting arrangement includes multiple annular portions that are stacked and interconnected in a layered fashion. These annular portions are designed in such a way as to allow multi-directional movement of the annular portions independently with respect to one another. The innermost annular portion is designed with a through bore. This bore is specifically made for receiving an end of the cold water pipe that is to be attached to the vessel. The internal design of the bore is such that it can accommodate the cold water pipe securely and with minimal leakage, ensuring that the flow of cold water through the pipe is not compromised. The outermost annular portion is configured for attachment to the vessel. The design of this outermost portion is such that it can be securely fastened to the vessel, ensuring a stable and secure connection between the cold water pipe and the vessel. Each annular portion is designed to fit within the concave wall of the next outer annular portion, creating a nested structure. Such nested structure allows each annular portion to move independently of the others. This flexibility enables the joint to accommodate multidirectional movements, including rotational and horizontal shifts, tilts, and rotations. Further, the inherent design of the concave wall serves a twofold purpose: one, it naturally complements the convex shape of the next inner annular portion, facilitating a smooth sliding interaction; two, it allows for greater distribution of forces over the interface area between the annular portions, thereby reducing localized stresses and contributing to the joint's overall durability. Thereby, the nested structure enhances the load distribution capabilities of the joint. As the loads or forces are applied to the joint, they are distributed and shared among the nested annular portions. This design feature prevents localized stress concentrations and ensures that the loads are evenly distributed, enhancing the stability and overall structural integrity of the joint, which, in turn, also contributes to the efficient operation and longevity of the OTEC system. In an embodiment, the joint comprises a middle annular portion concentrically nested between the innermost and outermost annular portions, wherein: - the innermost annular portion comprises a convex outer wall; - the middle annular portion comprises: a concave inner wall for slidably engaging the convex outer wall of the innermost annular portion; and a convex outer wall; and - the outermost annular portion comprises a concave inner wall for slidably engaging the convex outer wall of the middle annular portion. Herein, in the joint, the middle annular portion is concentrically nested between the innermost and outermost annular portions. The innermost annular portion is designed with the convex outer wall. This design feature provides structural integrity to the joint, and also facilitates the sliding engagement with the middle annular portion. The convex shape of the outer wall of the innermost annular portion naturally complements the concave shape of the inner wall of the middle annular portion, ensuring a smooth, sliding interaction between these components. The middle annular portion, as specified, has a two-fold design. On one side, the middle annular portion includes a concave inner wall, designed to slidably engage with the convex outer wall of the innermost annular portion. This concave-convex interaction ensures a smooth, low-friction engagement, allowing for independent multidirectional movement of the annular portions. On the other side, the middle annular portion features a convex outer wall, designed to engage with the concave inner wall of the outermost annular portion. This mirroring of shapes ensures similar benefits as the inner engagement, providing a smooth, sliding interaction that can withstand the multidirectional movement and loads imposed by the ocean environment. Further, the outermost annular portion, designed for attachment to the vessel, includes the concave inner wall. This concave design is specifically chosen to slidably engage with the convex outer wall of the middle annular portion. This engagement allows for the necessary multidirectional movement between the cold water pipe and the vessel, while also maintaining a secure and robust attachment. In an embodiment, the through bore is tapered. That is, the innermost annular portion has a tapered through bore. The tapering of the through bore serves several practical and mechanical advantages in the design and operation of the joint. The tapered through bore is designed to receive the end of the cold water pipe. The tapering ensures a snug fit and secure engagement between the pipe and the joint, providing a robust and leak-proof connection. This further allows for ease of assembly and disassembly, which is particularly beneficial during installation, maintenance, or repair operations. Additionally, the tapered design contributes to the distribution of stress along the length of the bore, as opposed to it being concentrated at a single point. This feature reduces the risk of mechanical failure, enhancing the overall reliability and longevity of the joint. Furthermore, the tapering can assist in alignment of the cold water pipe within the bore, ensuring proper connection therebetween. In an embodiment, the joint comprises a tapered collar for receiving the end of the cold water pipe, wherein the through bore is arranged to receive the tapered collar. That is, the joint may also incorporate a tapered collar, designed to receive the end of the cold water pipe. This tapered collar is arranged to fit within the tapered through bore of the innermost annular portion. The tapered collar ensures a secure and precise fit of the cold water pipe within the joint. For this purpose, the tapering of the collar is designed to match with the tapering of the through bore, providing a snug and secure engagement that effectively seals the connection, preventing any leakage or seepage of water. The tapered collar may also facilitate an efficient assembly and disassembly process. The matching tapering allows the tapered collar and the through bore to interlock smoothly, reducing the time and effort required for installation, maintenance, or replacement operations. In an embodiment, the tapered collar is formed from two symmetrical half portions. That is, the tapered collar that receives the end of the cold water pipe is designed to be formed from two symmetrical half portions. Each of these half portions may be separately attached or detached from the pipe, facilitating a more manageable and efficient installation or maintenance process. This is particularly beneficial in the marine environment where working conditions can be challenging. The symmetrical design ensures that each half portion of the collar is identical, providing a balanced distribution of forces across the collar when engaged with the pipe and the through bore. This balance minimizes the risk of localized stress concentrations, enhancing the overall structural integrity and durability of the joint. Further, such design allows each half portion to expand or contract (like thermal expansion) independently, preventing any deformation that may otherwise compromise performance of the joint. Additionally, by using two identical half portions, manufacturing processes for the tapered collar may be streamlined, reducing production time and costs. In an embodiment, the tapered collar comprises a recess for receiving an interface flange extending from an end of the cold water pipe. Such recess in the collar, that accommodates an interface flange, ensures a secure and precise connection between the cold water pipe and the joint. The interface flange snugly fits into the recess, providing a mechanical interlock that minimizes the risk of disengagement or leakage. The interface flange, when engaged with the recess, may also assist in properly aligning the cold water pipe within the joint, ensuring efficient water flow. The interface flange may be easily inserted into the recess during assembly, and similarly removed during disassembly, reducing the time and effort required for installation or maintenance operations. It may also be understood that the location of the interface flange also allows the water-level in the cold water pipe to alter without associated pumps drawing in air or causing cavitation. In an embodiment, the concave wall of one or more of the annular portions is provided with a recess comprising a race and a bearing element. That is, the recess is incorporated into the concave wall of one or more of the annular portions, which, in turn, houses a combination of the race and the bearing element. The use of the race and the bearing element within the recess of the concave wall allows for smooth and efficient multidirectional movement of the annular portions with respect to one another. Moreover, the integration of the race and bearing element system within the recess of the concave wall ensures that the movement of the annular portions is not only smooth but also controlled. Additionally, the recessed design of the race and bearing element system helps protect these components from environmental factors such as saltwater, reducing the risk of corrosion and wear. In present examples, the bearing element may include one of ball bearing, roller bearing, and the like. Herein, for instance, the roller bearing elements roll within the race, providing low friction motion that facilitates the independent movement of the annular portions even under high loads or in harsh marine conditions. In an embodiment, the recess extends annularly around the annular portion in a continuous loop. Such annularly extending recess provides a continuous track for the bearing elements to move along. The race, being housed in this recess, benefits from the continuous surface area, providing a smooth, unrestricted path for the bearing elements. For instance, this design enables the roller bearing elements to roll unhindered around the entire circumference of the annular portion, facilitating the multidirectional movement of the annular portions with respect to one another. By extending around the full circumference of the annular portion, the recess distributes the forces exerted on the joint more evenly, thereby reducing localized stress points and enhancing the overall durability and lifespan of the joint. Also, with the race extending around the entire annular portion, there are no gaps or discontinuities that could potentially allow water ingress, which helps to enhance the sealing capabilities of the joint. In an embodiment, the race has an outer side inserted into the recess and an inner side in contact with the bearing element. In other words, the race, which is housed in the annularly extending recess, has the outer side that is inserted into the recess, and the inner side that is in contact with the bearing element. The positioning of the outer side of the race within the recess ensures a stable and secure placement of the race within the joint. Herein, the outer side of the race may fit snugly into the recess, preventing any undesired movement or displacement of the race that could interfere with the smooth operation of the joint. The inner side of the race, on the other hand, provides a suitable surface for the bearing elements to roll upon. The smooth and well-contoured surface of the inner side of the race minimizes friction between the race and the bearing elements, enabling the bearing elements to move freely and smoothly. In an embodiment, the outer side of the race comprises a sealing element. Herein, the sealing element provides an additional layer of protection and functionality to the joint. The sealing element, affixed to the outer side of the race, serves as a barrier between the interior of the joint, particularly the through bore and the cold water pipe housed within it, and the surrounding environment. This prevents the ingress of water, debris, or any other foreign material into the joint. The sealing element also prevents the escape (egress) of fluid from within the joint. This ensures that the cold water flowing through the pipe and the joint remains contained, thus maintaining the efficiency of the OTEC system. In addition, the sealing element also serves to reduce friction between the race and the walls of the recess in which it is housed. This further facilitates the smooth, multidirectional movement of the annular portions with respect to each other. In an embodiment, the sealing element is formed from one of: a metal material, a metal alloy material, a metal composite material, a polymer material. These materials were selected because they have the resilience and strength required to maintain an effective seal, despite the pressures and movements inherent in offshore operations. Metal and metal alloy materials, for instance, offer high durability and strength, making them ideal for situations where the joint will be subjected to high mechanical stresses. On the other hand, a polymer material might be chosen for its excellent elasticity and corrosion resistance, making it a good choice for applications where the joint will be exposed to seawater or other corrosive substances over extended periods. Therefore, the choice of material for the sealing element will depend on the specific requirements of the operational environment, allowing for the optimal performance of the joint across a variety of offshore applications. In some examples, the joint may incorporate up to six fluid-actuated pistons, which helps in managing and mitigating the movements of the annular portions therein. Specifically, each of these pistons is designed to restrict the flow rate of fluid into and out of the joint. This restriction effectively slows down the movements of the pistons, which, in turn, dampens the motions of the gimbal mechanism in the joint. By reducing the rapid and potentially damaging movements of the gimbal, the pistons help to minimize wear and tear on the joint, extending its operational lifespan. In one or more configurations, the pistons may be arranged and connected in a manner that resembles a Stewart platform, as known in the art. Herein, each piston may be connected to both the vessel structure and the gimbal mechanism via universal joints, which allow for multi-directional movement, further enhancing the damping effect provided by the pistons. The joint, as described above, may be implemented for attaching the cold water pipe to a floating vessel, such as an Ocean Thermal Energy Conversion (OTEC) barge. The proposed design enables the joint to endure high flow rates, offer multiple degrees of freedom, withstand rotational and horizontal loading, and maintain a long fatigue life, thereby addressing a critical technical challenge in the field of OTEC systems. The design of the joint allows the pumps to be mounted as low as possible in the vessel, without any need to alter the structure of the barge. The pipe collar and flexible connections allow the pipe to be tailored for a range of operating conditions as the static pressure head will vary from location to location. The present joint, with its gimbal characteristics, reduces the stresses on the cold water pipe, allowing for the use of novel materials, further reducing the overall cost of the system. The present disclosure also relates to the cold water riser assembly as described above. Various embodiments and variants disclosed above, with respect to the aforementioned joint, apply mutatis mutandis to the cold water riser assembly. The cold water riser assembly encompasses the joint, as described, and the cold water pipe, such that this collective configuration optimizes the connection between the cold water pipe and the floating vessel. Herein, the cold water pipe functions as the conduit for the cold water drawn from the ocean depths. The design and construction of the cold water pipe are tailored to withstand the pressures and temperatures of the deep-sea environment while maintaining the structural integrity required to ensure a continuous flow of cold water to the OTEC system aboard the floating vessel. In an embodiment, the cold water pipe comprises an interface flange extending from an end of the cold water pipe, and wherein the innermost annular portion comprises a recess for removably receiving the interface flange. That is, the cold water pipe incorporates the interface flange extending from one of its ends, such that the interface flange facilitates the connection between the cold water pipe and the joint, enabling the assembly and disassembly of the OTEC system as needed. The innermost annular portion of the joint is designed with the recess specifically to accommodate the interface flange. This recess provides a secure and removable seat for the interface flange, ensuring a firm connection between the pipe and the joint while allowing for movement between them. This feature brings about flexibility and convenience during both the installation and maintenance phases of the OTEC system. The present disclosure also relates to the method of installing the cold water riser assembly on a floating vessel as described above. Various embodiments and variants disclosed above, with respect to the aforementioned joint and the aforementioned cold water riser assembly, apply mutatis mutandis to the present method. The present method offers a practical and efficient approach to securely connect the cold water pipe to the OTEC system aboard the floating vessel. The process begins with the installation of the joint, having the through bore, which is tapered, onto the vessel. The joint, including the innermost annular portion defining the tapered through bore, is installed in the appropriate location on the floating vessel while it is still at dock. The tapered through bore is designed to provide a precise and secure connection with the cold water pipe, reducing the risk of leaks or disconnections during operation. Once the joint is installed, the vessel is transported to the predetermined installation location. This could be anywhere within the tropical oceans, where conditions are most suitable for the OTEC system. Simultaneously, the cold water pipe is transported to the same installation location. Upon arrival at the installation site, the retrieval line is attached to the end of the cold water pipe. This retrieval line aids in the precise positioning of the cold water pipe through the tapered through bore of the joint during installation. Subsequently, the cold water pipe is flooded with water, causing it to sink in the ocean. It may be appreciated that the weight of the water-filled pipe aids in the sinking process. Thereafter, the retrieval line is pulled, effectively pulling the end of the cold water pipe up through the tapered through bore of the joint on the vessel. Further, the tapered collar is installed around the end of the cold water pipe, which is designed to fit snugly within the tapered through bore of the joint. Finally, the end of the cold water pipe is lowered so that the tapered collar sits within the tapered through bore of the joint, ensuring a perfect fit, effectively sealing the connection and preparing the OTEC system for operation. Presently, there are no adequate solutions for high flow-rate cold water pipe connections, as no such system is available in the wider market. Comparable fluid transfer systems in the oil and gas industry use flexible risers to transport hydrocarbons from subsea to a storage or production facility, but these systems operate at significantly lower flow rates. On land, comparable OTEC systems exist, but they require substantial land use and the installation of extensive piping infrastructure from the shore to the deep cold water, making these options costly. The present disclosure aims to solve the technical problem of connecting a cold water pipe to an OTEC barge in such a way that it can endure high flow rates, offer multiple degrees of freedom, withstand rotational and horizontal loading, and maintain a long fatigue life. Presently, there are no adequate solutions for high flow-rate cold water pipe connections, as no such system is available in the wider market. Comparable fluid transfer systems in the oil and gas industry use flexible risers to transport hydrocarbons from subsea to a storage or production facility, but these systems operate at significantly lower flow rates. On land, comparable OTEC systems exist, but they require substantial land use and the installation of extensive piping infrastructure from the shore to the deep cold water, making these options costly. The present disclosure provides an innovative solution to the technical problem of connecting a cold water pipe to a floating vessel, such as an OTEC barge, by utilizing the joint as described, in a manner that can endure high flow rates, offer multiple degrees of freedom, withstand rotational and horizontal loading, and maintain a long fatigue life. By solving the cold water connection challenge, the present disclosure unlocks the potential to provide baseload power to over 600,000,000 people living in the tropics. These islands are currently heavily reliant on fossil fuels, and OTEC represents a pathway for these island nations to reduce fossil fuel dependence without the significant loss of land required by traditional renewable energy systems. DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIGS. 1 and 2, in combination, illustrated are diagrammatic views of a joint (as represented by reference numeral 100), in accordance with one or more embodiments of the present disclosure. As illustrated, the joint 100 includes a plurality of concentrically nested annular portions, including an innermost annular portion 110, a middle annular portion 120 and an outermost annular portion 130 configured for attachment to a vessel. Herein, each annular portion 110, 120, 130 is slidably engaged with the concentrically next outer annular portion to allow multidirectional movement of the annular portions independently with respect to one another, as shown. Also, as shown, the innermost annular portion 110 defines a through bore 115 therein. Herein, the through bore 115 is tapered (as better shown in FIG. 4). Referring to FIG. 4, illustrated is a sectioned view of the joint 100 of FIG. 3, along a section AA taken along a centre of the joint 100. As shown, the innermost annular portion 110 includes a convex outer wall 112. The middle annular portion 120 includes a concave inner wall 122 for slidably engaging the convex outer wall 112 of the innermost annular portion 110, and a convex outer wall 124. The outermost annular portion 130 includes a concave inner wall 132 for slidably engaging the convex outer wall 124 of the middle annular portion 120. Referring to FIG. 5, illustrated is a diagrammatic view of the joint 100 with the through bore 115 arranged to receive a tapered collar 140. As shown, the tapered collar 140 is formed from two symmetrical half portions 140a and 140b. FIG. 6 illustrates a diagrammatic view of the joint 100 showing the two symmetrical half portions 140a and 140b, with one half portion 140a being removed for clarity. FIG. 7 illustrates a detailed diagrammatic view of the two symmetrical half portions 140a and 140b of the tapered collar 140. As shown, in combination of FIGS. 5-7, the tapered collar 140 includes a recess 142 for receiving an interface flange (shown in FIG. 8). Further, as better shown in FIG. 6, the concave wall of one or more of the annular portions, such as, herein, a concave inner wall (not shown) of the innermost annular portion 110 is provided with a recess 136. The recess 136 extends annularly around the middle annular portion 120 in a continuous loop. The recess 136 includes a race (not shown) and a bearing element (not shown). The race has an outer side inserted into the recess 136 and an inner side in contact with the bearing element. The outer side of the race includes a sealing element (not shown). Referring to FIG. 8, illustrated is a sectioned view of a cold water riser assembly 800 with a cold water pipe 10 coupled using the joint 100. Herein, in the joint 100, the through bore (not shown in FIG. 8) receives an end of the cold water pipe 10. As shown, the cold water pipe 10 includes an interface flange 12 extending from the said end thereof. The innermost annular portion 110 of the joint 100 includes the recess 136 for removably receiving the interface flange 12, along with the tapered collar 140 therein, which may be coupled and tightened with a plurality of screws 802 or the like. Referring to FIG. 9, illustrated is a flowchart listing steps involved in a method 900 of installing a cold water riser assembly on a floating vessel, in accordance with an embodiment of the present disclosure. At step 902, the method 900 includes installing on the vessel a joint including an innermost annular portion defining a tapered through bore. At step 904, the method 900 includes transporting the vessel to an installation location. At step 906, the method 900 includes transporting a cold water pipe to the installation location. At step 908, the method 900 includes attaching a retrieval line to an end of the cold water pipe. At step 910, the method 900 includes flooding the cold water pipe with water to sink the cold water pipe. At step 912, the method 900 includes pulling the retrieval line to pull the end of the cold water pipe up through the tapered through bore. At step 914, the method 900 includes installing a tapered collar around the end of the cold water pipe. At step 916, the method 900 includes lowering the end of the cold water pipe so that the tapered collar sits within the tapered through bore. It may be appreciated that the above steps are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the spirit and the scope of the present disclosure.

Claims

1. A joint for attaching a cold water pipe to a floating vessel, the joint comprising a plurality of concentrically nested annular portions, including an innermost annular portion defining a through bore for receiving an end of the cold water pipe, wherein the innermost annular portion comprises a convex outer wall; a middle annular portion concentrically nested between an innermost and outermost annular portions, wherein the middle annular portion comprises:- a concave inner wall for slidably engaging the convex outer wall of the innermost annular portion; and- a convex outer wall; and an outermost annular portion configured for attachment to the vessel, wherein the outermost annular portion comprises a concave inner wall for slidably engaging the convex outer wall of the middle annular portion; wherein each annular portion is slidably engaged with a concave wall of the concentrically next outer annular portion to allow multidirectional movement of the annular portions independently with respect to one another.

2. The joint of claim 1, wherein the through bore is tapered.

3. The joint of claim 3, comprising a tapered collar for receiving the endof the cold water pipe, wherein the through bore is arranged to receive the tapered collar.

4. The joint of claim 3, wherein the tapered collar is formed from two symmetrical half portions.

5. The joint of claim 3 or claim 4, wherein the tapered collar comprises a recess for receiving an interface flange extending from an end of the cold water pipe.

6. The joint of any preceding claim, wherein the concave wall of oneor more of the annular portions is provided with a recess comprising a race and a bearing element.

7. The joint of claim 6, wherein the recess extends annularly around the annular portion in a continuous loop.

8. The joint of claim 6 or claim 7, wherein the race has an outer side inserted into the recess and an inner side in contact with the bearing element.

9. The joint of claim 8, wherein the outer side of the race comprises a sealing element.

10. The joint of claim 9, wherein the sealing element is formed from one of: a metal material, a metal alloy material, a metal composite material, a polymer material.

11. A cold water riser assembly comprising a joint according to any preceding claim and a cold water pipe.

12. The cold water riser assembly of claim 11, wherein the cold waterpipe comprises an interface flange extending from an end of the cold water pipe, and wherein the innermost annular portion comprises a recess for removably receiving the interface flange.

13. A method of installing a cold water riser assembly on a floating vessel, the method comprising:- installing on the vessel a joint including an innermost annular portion defining a tapered through bore for receiving an end of the cold water pipe, wherein the innermost annular portion comprises a convex outer wall;- a middle annular portion concentrically nested between the innermost and outermost annular portions, wherein the middle annular portion comprises:- a concave inner wall for slidably engaging the convex outer wall of the innermost annular portion; and- a convex outer wall; and- an outermost annular portion configured for attachment to the vessel, wherein the outermost annular portion comprises a concave inner wall for slidably engaging the convex outer wall of the middle annular portion;- transporting the vessel to an installation location;- transporting a cold water pipe to the installation location;- attaching a retrieval line to an end of the cold water pipe;- flooding the cold water pipe with water to sink the cold water pipe;- pulling the retrieval line to pull the end of the cold water pipe up through the tapered through bore;- installing a tapered collar around the end of the cold water pipe; and- lowering the end of the cold water pipe so that the taperedcollar sits within the tapered through bore.

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