Symmetric or Pseudosymmetric Shared Mooring-Anchor System

This application claims priority to U.S. Provisional Patent Application No. 63/632,006 filed on Apr. 10, 2024, entitled, the contents of which are hereby fully incorporated by reference.

The field of the invention and its embodiments relate to a system and method of organizing one or more offshore variable resource structures.

Offshore structures may be used to capture the potential of offshore resources, for example, wind, wave, and seafood resources. Generally, it is desirable to organize systems for capturing offshore resources in such a way that they are economical. For example, certain arrangements of wind turbines may be configured to be more efficiently organized in an area to maximize the density of production as a main driver. Wind resources are often more powerful and more reliable offshore than on land. A fraction of global wind resources is available offshore in deep waters. Historically, offshore wind farms have been installed in relatively shallow waters, using wind turbines installed onto fixed-bottom foundations, for example monopile, jacket, or gravity foundations. These structures are fixed directly to the seabed or rest directly on it, and resist loads applied to the turbine and structure. Fixed-bottom foundations are uneconomical and impractical for use in deeper waters, for example waters deeper than 50 meters. Thus, there is a need for an improved system capable of capturing offshore resources in a manner practicable at greater depths.

To capture wind resources available in deep water, floating foundation concepts, such as semi-submersible and spar buoy systems, are being explored. Floating foundation systems include a buoyant foundation supporting a structure above the waterline, for example, a wind turbine. Station-keeping systems are used to restrain a floating foundation to the region of installation. Effective restraint is important to ensure the integrity of components that cannot be overstretched, for example electricity-carrying cables. Station-keeping systems may include mooring lines and seabed anchors. It is desirable that station-keeping systems provide sufficient redundancy in case a structural element, for example a mooring line or seabed anchor, were to fail. Certain station-keeping systems for floating foundations, such as catenary mooring systems, rely on the inertia of the mooring lines to provide station-keeping. They require the use of great lengths of heavy chain, which may be uneconomical in deep water or provide inadequate performance in waters of moderate depth with extreme wave exposures. In an example, some station-keeping systems for floating foundations rely on the use of mooring lines tied between foundations. This may allow for the use of less mooring line overall. Such systems are called shared mooring systems.

In another example, some station-keeping systems for floating foundations rely on the use of seabed anchors, for example suction anchors, to provide restraint. Installation of such anchors may be expensive, especially in deep water, and may be a driver of the total cost of installation. Therefore, it is desirable to use seabed anchors efficiently. It is being explored whether anchors can be shared between multiple floating foundations to reduce the total number of anchors required. Such systems are called shared anchor systems. Structures in offshore environments are subjected to forces from, for instance, wind, waves, currents, vessel impacts, and other exposures. Certain of these forces occur periodically, meaning they occur in cycles over time, which can result in fatigue demands on offshore structures. Fatigue demands may govern the useful life of an offshore structure and/or elements of a station-keeping system. It is desirable to reduce fatigue demands on some elements of offshore structures and systems.

In another example, the design of components in a station-keeping system depends in part on the magnitude of forces they experience. Larger components can tolerate larger forces but are also more expensive. It is desirable to reduce the magnitude of forces experienced by components.

Typically, the use of shared anchor systems in floating offshore wind farms has been widely studied, with substantial literature suggesting that such systems can offer cost savings by reducing the number of required anchors. A shared anchor serves to restrain more than one floating foundation, with a subset of these anchors, referred to as “multiline anchors,” being designed to support multiple mooring lines. Multiline anchors were first introduced by Fontana et al., and they differ from other shared anchors in their ability to resist forces from multiple directions. In a shared anchor system, an anchor may be used to restrain multiple floating foundations but may only be connected to a single mooring line. As a result, shared anchors do not necessarily need to resist forces in multiple directions. In contrast, multiline anchors must withstand forces in more than one direction, whether vertical or lateral. This distinction renders certain anchor types, such as drag embedment anchors, unsuitable for multiline applications, as they are designed to resist forces along a single axis.

There has also been teachings in the literature regarding the organization of floating foundation arrays using lattice structures. Fontana et al. describe candidate designs based on well-known lattice structures, including hexagonal and square unit cells, to explore a range of geometric configurations for floating offshore wind turbine (FOWT) farms. Similarly, EP2604501 discusses a “floating meshwork” where anchors are typically arranged in a triangular or quadrangular pattern. While hexagonal and square lattices have been widely considered, other configurations, such as those based on rectangular or parallelogram unit cells, may offer improved energy production density under specific wind conditions. Various studies have demonstrated that square lattices are less efficient than hexagonal or rectangular lattices over the same area due to reduced energy production density.

Some prior art relies on the use of a ‘distance wire’ and a ‘separation wire’ to separate buoys, which is likely a rigid connection and failure offers no redundancy for stability or station-keeping of that variable foundation. The distance wire might be very long and therefore prone to failure by buckling under compression. Under tension, the system may deform plastically and fail under fatigue.

Another consideration in offshore mooring systems is compliance, which helps mitigate fatigue-related failures. Compliance can be achieved through either material properties or geometric design. “Material compliance” refers to the use of low-stiffness materials, such as nylon, which is common in taut or semi-taut mooring systems. “Geometric compliance” refers to the arrangement of elements of the mooring system to decrease the effective stiffness, such as including extended mooring lines, mechanisms to accommodate long lines without increasing the mooring footprint, or loosely restrained intermediate buoys. Several approaches, including those proposed by Dimkin, TotalEnergies (USPTO 20250042514), and Honeymooring, have explored geometric compliance. It is also possible to combine both material and geometric compliance, such as by attaching a low-stiffness mooring line to a buoy that is laterally restrained. However, configurations where intermediate buoys lack direct lateral restraint, such as those described in EP2604501, may result in excessive drift.

Despite the potential benefits of shared mooring and shared anchor systems, reliability remains a concern. The interconnected nature of shared systems introduces an increased risk of cascading failures in the event of an anchor or mooring line failure. Hallowell et al. highlight this vulnerability, noting that while multiline systems provide advantages, they also reduce overall system reliability. Additionally, submerged buoys that rely on a single vertical mooring line pose a failure risk, as a broken line may cause the buoy to ascend uncontrollably to the surface. A failure of this type occurred in 2011, emphasizing the need for careful consideration of redundancy and restraint mechanisms in shared mooring and shared anchor systems.

Accordingly, there remains a need for an improved offshore mooring system. This need and other needs are satisfied by the various aspects of the present disclosure.

In accordance with the principles of the present invention, a shared mooring-anchor system may have one or more variable resource foundations, the one or more variable resource foundations supporting a variable resource. It is within the scope of this invention for this system to have at least one or more buoys oriented in a location that is not directly above at least one seabed anchor. It is within the scope of this invention for one or more buoys to include, but not be limited to, buoys near the surface or at the surface (i.e., above the waterline, or partially submerged) in addition to completely submerged. A shared mooring-anchor system may orient the variable resource near, at, or above the waterline of a body of water. A shared mooring-anchor system may connect the one or more variable resource foundations to the at least one near-surface buoy. The at least one near-surface buoy is connected to the at least one seabed anchor. The at least one seabed anchor is not vertically in alignment underneath the at least one near-surface buoy. An angle may be formed between the one or more variable resource foundations, the at least one near-surface buoy, and the at least one seabed anchor. The angle is not a right angle. This system also includes improvements that overcome the limitations of prior methods of organizing a system of one or more offshore variable resource structures, is now met by a new, useful, and non-obvious invention.

In some aspects, the techniques described herein relate to a method of organizing an offshore variable resource structure including, but not limited to, a variable foundation and/or a wind farm wherein each variable foundation is connected to at least one near-surface buoy which is connected to at least one seabed anchor where each anchor is not vertically oriented underneath the near-surface buoy.

The improved anchoring system is distinguished from prior art through advancements in anchor utilization, mooring line configuration, load distribution, compliance mechanisms, and reliability enhancements. Unlike conventional systems that rely on anchors which provide restraint for only one floating foundation, this system employs a shared anchor configuration, where anchors provide restraint for multiple floating foundations. Within this framework, multiline anchors are implemented to support multiple mooring lines, to facilitate stability by resisting forces from multiple directions, including both vertical and lateral loads. In contrast, general shared anchors may only connect to a single mooring line and do not necessarily need to accommodate multidirectional forces. This distinction necessitates the use of anchors capable of handling complex force distributions, excluding drag embedment anchors, which are optimized for unidirectional force resistance.

The system also integrates a structured mooring arrangement based on lattice geometries rather than the conventional triangular or quadrangular placement schemes commonly used. Unlike prior art, which focuses primarily on hexagonal or square lattices, this approach considers a broader range of unit cell configurations, including rectangular and parallelogram-based arrangements. By tailoring lattice selection to site-specific wind conditions and hydrodynamic interactions, the system enhances energy production density while mitigating wake losses, improving efficiency over traditional designs.

To address fatigue and dynamic loading, the system incorporates compliance mechanisms that enhance durability and stability. Compliance is achieved through a combination of material compliance, which utilizes low-stiffness materials such as nylon in mooring lines, and geometric compliance, which modifies mooring line configurations and introduces buoyancy elements. Intermediate buoys may be restrained laterally to prevent excessive drift, ensuring greater stability than prior designs. Compliance mechanisms reduce peak loads on multiline anchors, further extending system longevity.

Reliability improvements are incorporated to mitigate the risk of cascading failures. Unlike prior multiline anchoring systems, where the failure of a single anchor or mooring line could propagate across the system, this system includes secondary restraint mechanisms that redistribute loads among neighboring anchors in the event of partial system failure. Additionally, submerged buoys are multiply restrained to prevent uncontrolled surfacing events observed in prior designs when a mooring line fails. The system also optimizes load transmission and seabed interaction by ensuring more even force distribution across the anchor network. The use of multiline anchors designed for multidirectional resistance reduces localized stress concentrations, prolonging anchor lifespan and minimizing seabed disturbance. Unlike prior shared anchor designs, which often assume uniform load distribution, this system dynamically adjusts load paths based on real-time environmental conditions and floating foundation movements. Through these advancements, the improved anchoring system enhances structural integrity, reduces material and installation costs, and provides superior adaptability to site-specific conditions, addressing noted limitations of existing anchoring solutions.

Reference is made in the following detailed description to accompanying drawings, which form a part hereof, wherein like numerals may designate like parts throughout that are corresponding and/or analogous. It will be appreciated that the figures have not necessarily been drawn to scale, such as for simplicity and/or clarity of illustration. For example, dimensions of some aspects may be exaggerated relative to others. Further, it is to be understood that other embodiments may be utilized. Furthermore, structural and/or other changes may be made without departing from claimed subject matter. References throughout this specification to “claimed subject matter” refer to subject matter intended to be covered by one or more claims, or any portion thereof, and are not necessarily intended to refer to a complete claim set, to a particular combination of claim sets (e.g., method claims, apparatus claims, etc.), or to a particular claim. It should also be noted that directions and/or references, for example, such as up, down, top, bottom, and so on, may be used to facilitate discussion of drawings and are not intended to restrict application of claimed subject matter. Therefore, the following detailed description is not to be taken to limit claimed subject matter and/or equivalents.

In mathematics, the concept of symmetry has been rigorously defined. The rules of symmetry are used in fields such as materials science to describe the position of elements in space and their positions relative to one another.

An important concept is that of a lattice. A lattice is a set of points that repeats infinitely in space, in other words it is regular. This means that, as a minimum requirement, a lattice must display translational symmetry. It is possible to identify lattices that display higher symmetries, such as rotational symmetry and mirror symmetry. In three or more dimensions, other symmetries are possible.

In two dimensions, there are five configurations that meet the definition of a lattice. These are: monoclinic (also called oblique), orthorhombic (i.e., rectangular), rhombic, hexagonal, and tetragonal (i.e., square).

Each lattice can be defined by a unit cell. The unit cell is a shape that, if repeated infinitely by translation, could reproduce the lattice. The unit cell embodies the symmetries which define the lattice. The unit cell can be drawn such that its corners correspond to lattice points, for example, a square drawn onto four points of a tetragonal lattice. When the unit cell is drawn in this way, it touches several lattice points. However, the unit cell contains only one, for example, a square drawn onto four points of a tetragonal lattice contains only one-quarter of each lattice point (the remainder being contained within neighbor cells), and therefore contains a total of one lattice point. It is also possible to illustrate this by shifting the lines of the unit cells slightly in any direction while the lattice points are left in place. Each new cell will contain exactly one point somewhere within the shape. A unit cell that contains one lattice point is called a primitive unit cell.

The Wigner-Seitz method provides an alternative approach to defining a unit cell within a lattice. In this method, lines are drawn from a given lattice point to each of its nearest neighbors. Subsequently, additional lines are constructed perpendicular to these connections at their midpoints. The resulting polygon, formed by the intersections of these new lines, defines the Wigner-Seitz unit cell, which is centered on a lattice point. Notably, this unit cell contains only one lattice point, thereby classifying it as a primitive unit cell. The geometry of the Wigner-Seitz unit cell varies based on the lattice type. In a monoclinic lattice, the Wigner-Seitz unit cell is a centrally-symmetric polygon with six sides (not all equal), where no internal angles are equal to 60 or 90 degrees. For an orthorhombic lattice, the Wigner-Seitz unit cell is a rectangle with unequal side lengths. A rhombic lattice features a Wigner-Seitz unit cell in the shape of a rhombus, where no internal angles are equal to 60 or 90 degrees. In a hexagonal lattice, the Wigner-Seitz unit cell remains a rhombus but includes two internal angles of 120 degrees. The tetragonal lattice is characterized by a Wigner-Seitz unit cell in the shape of a square.

Beyond lattice points, additional symmetry positions can be identified within each unit cell. These positions adhere to specific distance constraints relative to subsets of the nearest neighbor lattice points and are most effectively examined using unit cells with corners positioned at lattice points. Among the symmetry positions are face centers, which are located at the midpoints of the edges of the unit cell. Since each unit cell shares these positions with adjacent cells, each unit cell effectively contains a total of two face centers. Centroids are located at the intersection of the diagonals of the unit cell, with each unit cell containing exactly one centroid. Body centers are positioned equidistant from three lattice points forming an angle that is not oblique, with each unit cell containing at least one and, in certain configurations, up to two body centers. In an example lattice structure, these symmetry positions may coincide. For example, in a tetragonal unit cell, the body center coincides with the centroid. However, this is not the case in a hexagonal unit cell, where two distinct body centers exist separately from the centroid. Furthermore, additional positions of sub-symmetry can be identified within a unit cell. These locations maintain equidistant relationships relative to lattice points, face centers, centroids, or body centers. Positions of increasingly complex sub-symmetry can be determined recursively, revealing deeper structural characteristics of the lattice.

The concept of a lattice, defined rigorously, only accommodates points positioned at regular intervals from one another. It is possible to adopt certain concepts for use in describing irregularly configured points. Even in irregular configurations of points, it is possible to use the Wigner-Seitz method to draw a cell around each point. Each cell may be unique. These cells are not unit cells because they cannot be repeated infinitely by translation to reproduce the original configuration. Given cells defined in this way for an irregular configuration of points, it is possible to identify positions of pseudosymmetry which show similar properties to the positions of symmetry of a unit cell, for example, points at the midpoint of cell edges which are similar to face centers. It is possible that cells defined in this way may contain a different number of positions of symmetry or a different number of positions of sub-symmetry than unit cells, for example, they may contain a total of more than two positions which are similar to face centers.

It is possible to use symmetry to define the position of objects in a system, such as the position when viewed on plan of offshore structures and the elements of a station-keeping system. If local conditions, for example soil conditions or bathymetric features, require the irregular placement of objects in a system, pseudosymmetry can be used.

Symmetry or pseudosymmetry may be used to position the elements of a station-keeping system with respect to an offshore structure or group of offshore structures, for example a floating foundation or group of floating foundations, such that the elements are shared most efficiently and the total number of elements is minimized. Use of symmetry or pseudosymmetry to most efficiently define the position of objects in a station-keeping system may allow economic advantages over other systems for station-keeping of offshore structures.

A station-keeping system can provide restraint to an offshore structure or group of structures. In shared mooring and shared anchor systems, restraining forces may arise due to the displacement of an offshore structure away from an equilibrium position; or due to pretensioning of mooring lines; or some due to some combination. Restraining forces originate in the seabed anchor and are transmitted to the offshore structure via mooring lines.

Station-keeping is optimized if restraining forces provided by the anchor are developed efficiently and applied to the offshore structure. Since offshore structures positioned near or at the waterline are most often subjected to disturbing forces in the lateral direction, for example, wind, wave, and current forces, station-keeping is optimized if restraining forces include a substantial component in the lateral direction.

In order to control fatigue demands placed on seabed anchors, it may be desirable not to connect offshore structures directly to seabed anchors. One or more buoys at an intermediate position or positions may be used to induce restraining forces in an anchor and transmit them to an offshore structure. A partially or fully submerged buoy connected to an anchor by mooring line will induce a tension force in the mooring line and a restraining force in the anchor due to its buoyancy.

Such a system may use mooring lines that are pretensioned, taut, semi-taut, or slack in the initial configuration. It may be desirable to introduce a degree of compliance to the system to reduce loads on the seabed anchor. Additional intermediate elements, for example, dashpot, elastomer, spring, or load-collecting elements, may be introduced between a buoy and an anchor to control the transmission of force between them.

In an embodiment, the anchoring system employs a Marine Ensemble Tension Station-keeping (METS) system for arranging and maintaining the position of floating offshore structures, particularly floating foundations for offshore wind turbines. The METS system differs from a taut system by introducing buoys near the waterline and ‘topline’ connections between the buoys and floating foundations. The buoys in the METS system are not positioned directly above an anchor but are instead connected to multiple anchors and positioned between them. These components offer several potential advantages under static and dynamic loading conditions. Under static loading, such as steady wind in laminar conditions, the floating foundation stabilizes at a position where environmental forces are counteracted by restraint forces, which develop at the anchors and are transmitted through the mooring lines. All else being equal, smaller anchor forces are preferable, as they allow for downsizing of anchor elements. Both the METS and taut systems achieve efficient restraint forces due to the advantageous angles at which forces are applied. However, the METS system gains a slight efficiency advantage as the buoy submerges further below the waterline.

In an embodiment the METS system also enables buoyant pretensioning, where a sufficiently large buoy provides constant pretension to anchor lines once fully submerged. This increases the magnitude of static anchor forces but reduces dynamic forces and force cycles, reducing the total force and improving fatigue performance. The METS system connects buoys to multiple anchors, fixing them in both lateral and vertical directions when pretensioning is sufficiently high. While this reduces buoy dissipation of dynamic energy, it also minimizes stress cycle magnitudes, further improving fatigue performance.

In the event of mooring line breakage, the primary design requirement is to prevent progressive failure of the mooring system, while a secondary requirement is to avoid the uncontrolled release of submerged buoyant elements. The METS system is more resilient against progressive failure due to the presence of redundant anchor lines. Because the METS system connects buoys to multiple anchors, a failure in one anchor line would be counteracted by the remaining anchor lines, restraining upward buoy motion to some extent.

A buoy may be positioned floating at the surface, partially submerged, or fully submerged. A buoy floating at the surface induces no restraining force until it is displaced because it generates no buoyant force until it is partially submerged. A buoy installed partially or fully below the waterline induces a restraining force in its initial condition, i.e., before it is displaced.

A buoy near the waterline may interfere with vessel navigation unless it is installed at sufficient depth. Installation of a buoy to a desired depth may be achieved by ballasting the buoy with water until it is negatively buoyant, then evacuating the buoy after any connection via mooring line has been achieved; or by a pretensioning operation; or by use of an unmanned underwater vehicle: or by use of divers; or by some other method. A submerged buoy may be identified by some element visible at the waterline.

A network of buoys may be used to develop restraining forces in multiple directions to achieve effective station-keeping.

Station-keeping is optimized if the induced restraining forces include a substantial component in the lateral direction. The line of action between the seabed anchor and the force-inducing element should not be vertical. A buoy used to develop restraining forces on an offshore structure may be positioned so it is not vertically above the seabed anchor, i.e., an angle that is not a right angle exists between the seabed anchor, the buoy, and the offshore structure.

Station-keeping for a group of offshore structures may be provided by a station-keeping system comprised of shared moorings, shared anchors and shared buoys. Symmetry or pseudosymmetry may be used to position the elements of the station-keeping system with respect to the group of offshore structures. Such a system may provide redundancy in the event of failure of certain elements of the station-keeping system. The efficiencies of such a system may allow for structural elements to be downsized or downgraded to achieve reductions in cost.

Station-keeping for rotational restraint may be provided by subdividing a mooring line between a shared buoy and an offshore structure so as to attach to the offshore structure at multiple positions. The restraint may be more effective if the subdivision occurs at a point near to the offshore structure.

Symmetry or pseudosymmetry may be used to position other relevant elements or appurtenances, for example, power infrastructure, instrumentation, monitoring equipment, wave energy converters, floating foundations for wind turbines or other variable resources, infrastructure to support aquaculture, or features to support maritime life.

illustrate improved anchoring systems and methods configured to enhance stability, load distribution, and compliance while addressing the limitations of prior systems. In particular,illustrate systems and methods of mooring floating offshore structures in which the floating structures are moored to at least three buoys. Each buoy, in turn, is moored to at least three seabed anchors.describe another embodiment of offshore mooring systems and methods, using one or more intermediate buoys to implement reciprocal base isolation employing a low-stiffness mooring line and a high-stiffness mooring line, for reducing dynamic loads on seabed anchors.describe another embodiment of offshore mooring systems and methods, using one or more intermediate buoys to facilitate energy dissipation through buoyant mass vertical motion as compared to strain energy.

The system incorporates a combination of shared anchors and multiline anchors, utilizing a structured mooring arrangement informed by lattice geometries. These advancements improve efficiency and reliability, particularly in offshore floating wind farms. An aspect of the system is the integration of compliance mechanisms to manage dynamic loading and fatigue. Compliance is achieved through both material compliance, which involves using low-stiffness mooring materials, and geometric compliance, which modifies mooring line configurations and introduces buoyancy elements.

One such material compliance mechanism, reciprocal base isolation, uses high-stiffness mooring materials in combination with low-stiffness mooring materials, such as nylon, to absorb loads and mitigate stress concentrations.

One such geometric compliance mechanism, hydrodynamic regulation, involves the use of an intermediate buoy that moves laterally and vertically in response to tension and environmental forces, providing additional flexibility in the system. This movement acts as a shock absorber, dissipating energy from environmental loads and reducing stress on the anchors and mooring lines. Unlike a fixed restraint system, this approach allows the buoy to dynamically adjust its position, absorbing fluctuations in force and preventing excessive strain on the mooring lines. This motion helps to manage peak loads, thereby enhancing the durability of the overall anchoring system. The system may include additional components to regulate the buoy's movement. ensuring that it remains within an optimal range and does not allow excessive strain in the mooring lines or introduce unintended instability. These systems collectively contribute to a more efficient and resilient anchoring system. By leveraging lattice-informed anchor arrangements, multidirectional load-resistant anchors, and adaptive compliance mechanisms, the system enhances structural redundancy, reduces material costs, and improves long-term durability.

is a flowchart that describes a method of organizing a system of one or more offshore variable resource structures, according to some embodiments of the present disclosure. In some embodiments, at, the method may include providing one or more variable resource foundations, the one or more variable resource foundations supporting a variable resource. At, the method may include providing at least one near-surface buoy. At, the method may include providing at least one seabed anchor. At, the method may include orienting the variable resource near, at, or above the waterline of a body of water.

In some embodiments, at, the method may include connecting the one or more variable resource foundations to the at least one near-surface buoy, the at least one near-surface buoy may be connected to the at least one seabed anchor, the at least one seabed anchor may be not vertically in alignment underneath the at least one near-surface buoy, an angle between the one or more variable resource foundations, the at least one near-surface buoy, and the at least one seabed anchor may not be a right angle. The method may include the steps ofto. In some embodiments, the method may include introducing a degree of compliance or flexibility to reduce a load on the at least one seabed anchor. In some embodiments, the system may be downsized.

is a block diagram that describes a shared mooring-anchor system. according to some embodiments of the present disclosure. In some embodiments, the shared mooring-anchor systemmay include at least one near-surface buoyand at least one seabed anchor. The shared mooring-anchor systemmay also include one or more variable resource foundations, the one or more variable resource foundationssupporting a variable resource, the variable resource may be oriented near, at, or above the waterline of a body of water. In another embodiment, the one or more variable resource foundationsmay be connected to the at least one near-surface buoy, the at least one near-surface buoymay be connected to the at least one seabed anchorin an arrangement to form a unit cell().best illustrates the unit cellmay include a lattice point, a face center, a centroid, and a body center. In another embodiment, the one or more variable resource foundationsmay be connected to the at least one near-surface buoy, the at least one near-surface buoymay be connected to the at least one seabed anchorin an arrangement to form an irregular cell().best illustrates the irregular cellmay include a point, a pseudo face center, a pseudo centroid, and a pseudo body center.

In some embodiments, the one or more variable resource foundations, the at least one near-surface buoy, and the at least one seabed anchormay be positioned based on rules of symmetry. The variable resource may be positioned at a position of symmetry of the unit cellbeing monoclinic. In some embodiments, the at least one near-surface buoymay be placed at the face center, the at least one near-surface buoymay be placed at 3 of the 4 positions per the unit cellto triangulate the variable resource.