Patent Description:
The anchoring system object of the present invention has unique characteristics that make it suitable to be used on floating platforms that serve as a basis for maritime structures where it is important to avoid pitching or rolling movement, as well as solving some drawbacks of other anchoring systems for floating platforms of the state of the art.

The present invention also relates to a method of installing a floating platform using said anchoring system.

The anchoring system object of the present invention is applicable to any type of structure intended to be located floating on the surface of the sea, and which needs to have several anchoring points on the seabed, to fasten the cables or anchoring chains of the floating platforms.

Floating platforms, especially those dedicated to supporting wind turbines for the generation of electrical energy from offshore wind energy, need anchoring systems that keep them in their position and contribute to their stability.

In the state of the art, platforms of the Tension Leg Platform (TLP) type are known. These platforms comprise three or more anchoring lines (usually chains or cables that connect the platform with piles anchored to the seabed). The anchoring lines of TLP platforms are designed to be disposed in tension, connecting the platform in an upright position to each of the piles anchored on the seabed. TLP platforms comprise a set of floats designed to produce an excess buoyancy of the platform (taking into account the weight of the structure that sits on the platform). This excess buoyancy ensures a high level of tension in the cables, which in turn ensures that they are always upright. In this way, the pitching and rolling movements of the platform and the structure that sits on the platform are avoided.

<CIT> describes a TLP platform as described in the previous paragraph.

A disadvantage of TLP platforms is that the high tension of the cables necessary to keep them in vertical position and thus avoid pitching and/or rolling movements also results in blocking movement in the vertical direction of the platform. Thus, when the tide rises, the platform cannot move upwards (due to the fact that the anchoring lines have reduced or no extensibility) and, therefore, the tension in the anchoring lines increases considerably. This causes a high risk of breakage of the anchoring lines and requires having high-section anchoring lines or increasing the number of anchoring lines. Additionally, in TLP platforms, in very low tide situations, the platform also descends and the anchoring lines can lose much of their tension, increasing the risk that the platform moves both vertically and laterally in an uncontrolled manner, and also increasing the risk that pitching and/or rolling movements occur (due to the thrust of the wind and/or waves on the platform and the structure that sits on it) that can result in the overturning of the platform.

To avoid the aforementioned drawbacks, other types of floating platforms are known where the anchoring lines are connected to a counterweight through pulleys located on the platform. These types of platforms allow the vertical and lateral displacement of the platform in the face of tides, waves and wind, thus making it unnecessary to have a large number of anchoring lines or anchoring lines of a high section.

Document <CIT> describes a platform as described in the previous paragraph.

An existing problem with the anchoring system described in the document mentioned in the previous paragraph is that floating platforms that use said anchoring system are subjected to pitching and/or rolling movements that can become important, which make the anchoring system described in said document not the most suitable for:.

In order to remedy the aforementioned drawbacks, the present invention relates to a anchoring system.

The anchoring system object of the present invention comprises a floating platform (for example, to support a wind turbine) and at least one pair of anchoring lines (for example, anchoring cables or anchoring chains), configured to fix or anchor the floating platform to the seabed (for example to piles driven into the seabed, or to bottom weights or anchoring rings deposited on the seabed) by at least one bottom section of each anchoring line.

Each anchoring line also comprises a central section attached to a counterweight.

Each pair of anchoring lines comprises two anchoring lines arranged in a plane passing through a central axis of the floating platform. These anchoring lines arranged in the same plane are located respectively on either side of the central axis of the floating platform.

The central axis of the floating platform preferably defines a radial symmetry of the floating platform.

The anchoring system comprises at least one first rotary fixing means (e.g., a pulley) for each anchoring line, wherein each first rotary fixing means is fixed to a first point of the floating platform and is configured to fix each anchoring line to the floating platform at said first point of the floating platform, allowing sliding of the anchoring line on said first rotary fixing means.

As a novel feature, in the anchoring system object of the present invention:.

By means of the anchoring system described above, the pitch and/or roll of the floating platform is cancelled or drastically reduced with respect to other anchoring systems such as that described in document <CIT>, while leaving the floating platform free to move vertically, also allowing restricted horizontal movements.

By means of the anchoring system described above, the pulley system used in other anchoring systems by means of pulleys and cables in the state of the art is mechanically simplified. Since there are no central pulleys located in correspondence with the central axis of the floating platform, the anchoring system is simpler and, moreover, all the central pulleys of all the arms that make up the system do not coincide in almost the same point.

Additionally, by means of the anchoring system described above, the pendular movement characteristic of the central counterweight, induced by the horizontal movements of the platform due to the waves, is eliminated.

Likewise, by means of the anchoring system described above, the need to have a central well in the hull (main structure or central structure) of the platform is eliminated, which in the state of the art was necessary for the passage of the central sections of the anchoring lines (those that hold the central counterweight).

Preferably, the floating platform comprises a pair of projecting structural arms for each pair of anchoring lines. Thus, each pair of protruding structural arms comprises a first arm and a second arm located symmetrically with respect to the central axis of the floating platform. Each projecting structural arm is attached to a main structure (or hull) of the floating platform. Each projecting structural arm runs radially from a first end attached to the main structure of the floating platform to a second end projected to the outside of the floating platform. Thus, the at least one first rotary securing means is fixed to the floating platform in correspondence with the second end of the first arm, and the at least one second rotary securing means is fixed to the floating platform at a point located in correspondence with the second arm.

The main structure (or hull) of the floating platform may have a shape in the form of a cylindrical, conical or pyramidal shaft. Additionally, the anchoring system may comprise a plurality of spokes connected to this main structure, where at each free end of each spoke there is a flotation element. These flotation elements may comprise at least one flood chamber.

The main structure (or hull) of the floating platform may lack the aforementioned spokes with floating elements at their ends. However, the main structure or hull, with a shaft-shaped geometry, may comprise at least one flotation element. This at least one flotation element may comprise at least one floodable chamber.

The floating elements provide buoyancy and, when they are floodable, allow the floating platform to be moved or towed to its place or site of installation, with a reduced weight and, subsequently, flood the corresponding floating elements to provide tension to the anchoring cables, increasing their stability.

When the flotation elements are located at the end of spokes attached to the shaft, the structure is particularly stable, and appropriate to guarantee the stability of the floating platform in the installation maneuver.

Alternatively to the shaft-shaped geometry, the main structure (or hull) of the floating platform may comprise a ring-shaped geometry, said ring being attached by means of spokes to a cylindrical, conical or pyramidal shaft. This main structure may constitute a flotation ring (a float or ring-shaped flotation element). This flotation ring may comprise at least one flood chamber.

This structure in the form of a floating ring also provides great stability to the floating platform.

The anchoring system may comprise at least one third rotary fastening means (e.g., a pulley) for each anchoring line. Each third rotary fixing means is fixed to a third point of the floating platform and is configured to fix each direct subline of each anchoring line to the floating platform at said third point of the floating platform allowing sliding of the direct subline by said third rotary fixing means, such that each direct subline runs from the first rotary fixing means to the counterweight passing and sliding by the third rotary fixing means.

This third rotary fixing means allows the direct subline to run in an intermediate section parallel to one of the protruding structural arms, so that the central section (which is directed from the third rotary fixing means to the counterweight) runs closer to the central axis of the floating platform.

Additionally, the anchoring system may comprise at least one rotary guiding means (e.g., a pulley or fluted wheel) for each anchoring line, wherein each rotary guiding means is fixed to a fourth point of the floating platform and is configured to guide the course of the cross subline of each anchoring line allowing the cross subline to slide by said rotary guiding means, such that each cross subline runs between the first rotary fixing means and the second rotary fixing means passing and sliding by the rotary guiding means.

This rotary guiding means allows the crossed sub-line to avoid obstacles in its path from the first rotary fixing means through the central axis to the second rotary fixing means. By means of this rotary guiding means, it is possible to prevent the crossed sublines of all the anchoring lines from colliding with each other, or the crossed sublines from colliding with the main structure of the floating platform.

Preferably, each bottom section of each anchoring line comprises a buoy that divides the bottom section into a first portion that runs between the seabed and the buoy and a second portion that runs between the buoy and the at least one first rotary fixing means.

The above feature facilitates the installation of the floating platform, since the bottom weight, pile or anchoring ring attached to a first portion of the bottom section (with the buoy) can be arranged in a pre-installation maneuver (once the location of the floating platform has been chosen) and, subsequently, connect the second portion of the bottom section directly to the buoy, when the floating platform and the counterweight have moved to the installation site.

Also preferably, the counterweight of the anchoring system comprises at least one floodable flotation chamber. This feature also facilitates the transport of the counterweight (which can be transported without flooding with less weight), and also facilitates a progressive contribution of tension to the anchoring lines, as the at least one floodable flotation chamber is filled.

The present invention also relates to a method of installing a floating platform, employing an anchoring system as described above.

Thus, the method of installing a floating platform object of the present invention comprises:.

In the anchoring system of the present invention, the floating platform does not need to rest on the bottom, so it is suitable for areas of any sea depth, both near the coast (for example, <NUM> deep), and away from it (up to depths of <NUM> or more) and at any intermediate distance, since it is able to withstand very severe storms.

In the preferred embodiments of the anchoring system of the invention, several platforms (for marine wind turbines) are presented that are intrinsically stable in all their possible states, from manufacture in port, to their final operating condition, through the transport to the wind farm and the assembly phases of the system cabling, flooding of the counterweight and final adjustments. Therefore, the installation process is much simpler and faster. No special ships are needed, just a small conventional tugboat.

The anchoring system of the invention makes it possible to uninstall and move the floating platform to another location, by means of a novel more simplified and faster procedure than that proposed in <CIT>.

The main features and advantages of the anchoring system of the invention are:.

The anchoring system of the invention is applicable to any floating marine installation, in which the movement requirements are an important condition of the design, especially in the following cases:.

From the second point of view, the energy extracted from the damping lines can be dissipated directly in the form of heat or can be converted into electrical energy. If it is dissipated, the necessary equipment is cheaper and simpler, the movements of the platform would be the same but the full potential of the system is not exploited. If it is decided to use the available energy, it can be stored in batteries or consumed on board in the facility.

Thus, one or more damping lines with or without energy collectors may be included in the anchoring. The fundamental mission of these lines is to reduce the vibrations (oscillations) that can occur as a result of the elasticity of the anchoring cables, in a system that is conceptually quite rigid (in general it is a hyperstatic system). These low/medium frequency vibrations could significantly increase the accelerations on the platform and render it unacceptable. The incorporation of the shock absorber lines almost completely cancels out these vibrations (oscillations).

These damping lines are very similar to the locking anchoring lines (the anchoring lines attached to an anchoring element or pile on the seabed), with the difference that one of their pulleys (internal or external) drives an electric generator (if the energy is to be used) or a hydraulic or electrical dissipator (if they only function as dampers).

As part of the explanation of at least one embodiment of the invention, the following figures have been included, by way of illustration and in a non-limiting manner.

The present invention relates, as mentioned above, to an anchoring system comprising a floating platform (<NUM>).

Some elements cited in this description are defined below.

Float or flotation element (<NUM>): a closed and watertight wrapper, totally or partially submerged in water, which can be subjected to hydrostatic or hydrodynamic forces due to waves or sea currents. If it is partially submerged, it can also be subjected to forces originating from the wind on its side or superstructures.

Hull or main structure (<NUM>): a structure comprising one or more watertight floats or flotation elements (<NUM>) that form a rigid and resistant assembly, in which at least one of them is partially submerged.

Floating platform (<NUM>): a hull or main structure (<NUM>) of any shape or configuration, which additionally comprises other elements or structures (spokes (<NUM>), protruding structural arms (<NUM>), floating elements (<NUM>), etc.), dedicated to any function (accommodation, industrial or recreational facilities, windmill support, etc.), equipped with the anchoring system proposed herein.

External agents: the wind, sea currents, waves, internal load movements or any element external to the floating platform (<NUM>) that tries to move it away from its design position or tries to transmit pitch or roll movements.

Tension of the cable or anchoring line (<NUM>): tensile force to which the cable or anchoring line (<NUM>) is subjected (due to its flexible nature, the cable cannot be subjected to compressive forces).

Central counterweight (<NUM>): a fully submerged hull, of average density greater than <NUM>/dm<NUM>, which keeps the anchoring lines (<NUM>) that are connected to it taut. In simple installations there is only one counterweight (<NUM>) located on the central axis (<NUM>) of the floating platform (<NUM>), but there may be several counterweights (<NUM>) or be located below other points of the floating platform (<NUM>).

Anchor block or bottom weight (<NUM>): a (large) weight supported on the seabed (<NUM>), to which the cables or anchoring lines (<NUM>) of the anchoring system are attached. In other conventional installations, it is equivalent to the anchor, to the 'deadweight' that keeps buoys or other marine elements in their position or to any other type of anchorage by means of piles.

Anchor cable or anchoring line (<NUM>): a cable, chain or tie of any type that keeps the floating platform (<NUM>) attached to the bottom weight (<NUM>), preventing the floating platform (<NUM>) from being dragged by external agents. Each anchoring line (<NUM>) is composed of the following elements:.

More specifically, as will be seen below, the anchoring line <NUM> comprises a cross subline (200c) and a direct subline (200d). The intermediate section (<NUM>) is the part of the cross subline (200c) of the anchoring line (<NUM>) that joins the first rotary fixing means (<NUM>) (or external pulley) with the second rotary fixing means (2c) (or internal pulley).

In addition, in the case of a third rotary fixing means (2d) (or internal pulley), the intermediate section (<NUM>) also refers to the part of the direct subline (200d) of the anchoring line (<NUM>) that joins the first rotary fixing means (<NUM>) with the third rotary fixing means (2d).

A complete anchoring line (<NUM>) is a set of two anchoring sublines (a direct subline (200d) and a cross subline (200c)), which share the same bottom weight (<NUM>), a part of the bottom section (<NUM>) of the anchoring cables and the corresponding part of the central counterweight (<NUM>). Its external or external pulleys (first rotating fixing means (<NUM>)) are very close to each other; in general, they are parallel with the same axis of rotation. On platforms using protruding structural arms (<NUM>), these outer sheaves hang from the end of the same protruding structural arm (<NUM>). Instead of two outer sheaves, it may comprise a single outer sheave with at least two sheaves (one sheave for the direct subline 200d and another sheave for the cross subline 200c).

Floating platforms (<NUM>) with very elongated geometries may have installed several groups of anchoring lines <NUM> acting on the same counterweight (<NUM>) (the centerlines of each group of anchoring lines <NUM> are fastened to different points of the counterweight (<NUM>), which is also elongated).

On particularly large floating platforms (<NUM>), there may be several groups of anchor lines (<NUM>), each group having its corresponding counterweight (<NUM>).

In all the preferred embodiments shown in the figures, the anchoring system has only one group of anchoring lines (and therefore a single counterweight (<NUM>)).

Most of the elements that make up the proposed system have been described above. There are other optional elements that can help the proper functioning of the main elements and other elements that can help the actual implementation in a given platform.

The simplest configuration is composed of four locking anchoring lines (<NUM>), each of which is composed of two sub-lines (one direct (200d) and one cross (200c)), each of which includes:.

Since the three sections (<NUM>, <NUM>, <NUM>) are part of the same cable, the sum of their lengths is constant. The mission of these elements is to prevent the roll and pitch movement of the floating platform <NUM>, allowing it to move horizontally or vertically.

If the floating platform (<NUM>) moves vertically a height V, the counterweight moves vertically a height 2V, but the forces on the floating platform (<NUM>) hardly vary.

If the floating platform (<NUM>) moves a quantity H horizontally, the anchoring lines (<NUM>) generate an opposing horizontal force that tends to return the floating platform (<NUM>) to its original position. The vertical forces on the floating platform (<NUM>) hardly vary. The counterweight (<NUM>) moves slightly upwards.

If a bending moment is applied that attempts to cause the floating platform <NUM> to rotate in the pitch direction, the tensions of the cables of the anchoring lines <NUM> vary to compensate for it and prevent rotation; if that bending moment increases sufficiently, one of the anchoring lines <NUM> will lose its tension and the floating platform <NUM> will be held only by the other anchoring lines <NUM>. In general, the hull or central structure (<NUM>) of the floating platform (<NUM>) will begin to submerge slightly.

When all but one of the anchor lines (<NUM>) have been untensioned, the overturning of the floating platform (<NUM>) may begin. This overturning will be reversible or irreversible depending on the particular geometry of the assembly as a whole.

The theoretical basis of the invention is based on a geometric construction, as can be seen in <FIG>.

Each anchoring cable can be considered almost non-extensible. If we assume it consists of three sections with lengths: T6 (length of the central section), T7 (length of the intermediate section) and T8 (length of the bottom section), the sum of lengths (T6, T7, T8) of the three sections (<NUM>, <NUM>, <NUM>) is constant: T6 + T7 + T8 = constant.

Since the intermediate section (<NUM>) does not vary in length, it is also fulfilled that: T6 + T8 = constant.

The floating platform (<NUM>) has two anchoring lines (<NUM>) (if planar movement is assumed, if three-dimensional movement is considered there would be at least four anchoring lines (<NUM>), crossed two to two, but the result is the same). If we compare the lengths of the sections in two different positions of the platform:.

Since each line (P, Q, R, S) maintains its length: <MAT>.

Since <MAT> (they represent the same measure).

If we start from two symmetrical lines, i.e. <MAT>.

That is, the two outer pulleys (first rotary fixing means (<NUM>)) and the two bottom weights (<NUM>) form an "articulated" quadrilateral in which their opposite sides are equal and therefore the upper side always remains parallel to the lower side, regardless of the position of the center of the floating platform (<NUM>).

To block the rotation of the floating platform (<NUM>) in a plane, two anchoring lines (<NUM>) are sufficient, as seen in <FIG> or <FIG>. For example, if the pitch angle is to be avoided, two anchoring lines (<NUM>) are needed in a longitudinal plane, with one outer pulley at the bow and one outer pulley at the stern, with the two inner pulleys between them (the intermediate sections of the anchoring cable need not be the same). If the roll angle is to be avoided, the two anchoring lines (<NUM>) must be in a plane transverse to the waves.

<FIG> and <FIG> show a schematic of a complete anchoring line (<NUM>) formed by a forward subline (200d) and a cross subline (200c), representing the positions of the floating platform (<NUM>) in its design condition (<FIG>) and in any other position (<FIG>).

The two inner pulleys (2d: direct and 2c: cross) are at the same distance from the central axis (<NUM>) of the floating platform (<NUM>) (actually the pulley axes are at different distances, but such that the central sections (<NUM>) appear to come from symmetrical points: the point of contact of the cable with the pulley). In the design condition (<FIG>), the lengths of the two sublines (200c, 200d) are different, but are such that the central sections (6d, 6d) are equal, so that the central counterweight (<NUM>) is located in correspondence with the central axis (<NUM>) of the floating platform (<NUM>).

When the floating platform (<NUM>) is moved (<FIG>), the bottom sections 8d and 8c change in length, but remain equal to each other. The intermediate sections (7d and 7c) do not vary in length (the pulleys move rigidly with the platform). Since the total length of each subline (200c, 200d) does not vary, the central sections (6d and 6c) also vary in length, but remain equal to each other, i.e. the central counterweight (<NUM>) moves vertically, but remains located in correspondence with the central axis (<NUM>) of the floating platform (<NUM>). In this way, the pendular movement that the counterweight (<NUM>) could have in the original version of the anchoring system is totally eliminated.

When two complete anchor lines (<NUM>) are combined (each with a direct subline (200d) and a cross line (200c)), applying the same reasoning as when the lines are central (on state-of-the-art platforms with central well through which the central lines pass), the bottom sections (<NUM>) of each complete anchoring line (<NUM>) remain equal to each other, regardless of the position of the floating platform (<NUM>). In this sense, the anchoring system (with direct (200d) and crossed (200c) sublines) behaves as if all the sublines were central.

The scheme of operation of the system with direct (200d) and crossed (200c) sublines, can be seen in <FIG>. If it had only central sublines it would be the same scheme, with the angle (β) between the central sections (<NUM>) being null (i.e. they would be vertical).

When the external agents (winds, waves or sea currents) act on the floating platform (<NUM>), they generate a bending moment (Mf) and a force (Fx) that pushes the floating platform (<NUM>) to the position seen in the figure.

On the other hand, the central counterweight (<NUM>) has a net weight (dry weight minus hydrostatic thrust) that tensions the two cables of the anchoring lines (<NUM>) generating two forces, in windward (F1) and leeward (F2). If the inertia forces due to the movements of the floating platform (<NUM>) and the counterweight (<NUM>) are ignored, the forces on the direct and cross cables on each side are equal: <MAT>.

Due to the balance of forces in the counterweight, it is fulfilled that: <MAT>.

These forces are transmitted by the cable to the bottom weights (<NUM>).

For the floating platform (<NUM>) to be in equilibrium, the two forces F1 and F2 applied on the bottom sections (<NUM>) must fully compensate for the bending moment of the external agents (Mf).

Since the cables do not work by compression, as long as F2 is positive, the floating platform <NUM> will remain horizontal and then begin to tilt leeward.

On the other hand, the balance of horizontal forces requires that: <MAT>.

According to a variant of the anchoring system wherein the anchoring lines (<NUM>) are divergent, the pitch angle imposed by external forces acting on the floating platform (<NUM>) can be corrected. The elasticity of the anchoring lines (<NUM>) means that when the floating platform (<NUM>) is subjected to external forces, the windward cables lengthen and the leeward cables shrink: as a result of these deformations the floating platform (<NUM>) acquires a small pitch angle leeward.

The indicated variant consists of giving an angle to the bottom sections (<NUM>) of the anchoring lines (<NUM>), separating out the anchoring points of the vertical of the outer pulleys (first rotary fixing means (<NUM>)), as can be seen in <FIG>.

When the floating platform (<NUM>) is moved horizontally dragged by the wind, the deck of the floating platform (<NUM>) does not remain horizontal and instead turns windward. This angle of rotation is geometrically related to the angle of the bottom sections (<NUM>) and to the depth of the seabed (<NUM>), being approximately proportional to the magnitude of the horizontal movement. By adjusting the angle of the bottom sections (<NUM>) of the anchoring lines (<NUM>), the pitch of the floating platform (<NUM>) can be cancelled exactly due to the elasticity of the anchoring lines (<NUM>), whatever the horizontal force applied (until any of the lines are deployed).

Below are proposed, by way of example, three alternatives for fastening the cables of the bottom section (<NUM>) on the seabed (<NUM>). In all of them, intermediate buoys (<NUM>) can be included in the bottom sections (<NUM>) (located at a depth similar to that of the counterweight (<NUM>), in its design position) joined by cables or chains to the anchorage on the seabed (<NUM>).

In this way, the final installation is very simple, since it is enough to hold the cables in the buoys (<NUM>) and the floating platform (<NUM>) is fully operational.

Comparison of the anchoring system of the present invention with TLP (Tension Leg Platform) platforms:
Apparently, floating platforms (<NUM>) with a TLP-type anchoring system serve the same purpose as a floating platform (<NUM>) with the anchoring system of the present invention. Their aim is to override the pitch/roll movement of the floating platform (<NUM>). However, the principle of operation of both is radically different and their kinematic and dynamic characteristics are also different, as can be seen in the following table:.

The figures of the present patent application are described and discussed below.

In all the figures, the depth at which the seabed (<NUM>) is located has been reduced, so that the images are more proportionate and easier to interpret. If the seabed were so close, it would not be worth using floating platforms (<NUM>), since it would be better if they were directly supported on the seabed (<NUM>). In actual projects, the counterweight (<NUM>) would also be proportionally deeper than shown in the figures.

<FIG> shows a basic diagram of the locking anchoring lines (<NUM>) (those that prevent the rotational movement of the floating platform (<NUM>)). An installation of this type consists of a floating platform (<NUM>) floating in the sea, provided with two or more anchoring lines (<NUM>) (the minimum is two anchoring lines (<NUM>) when you only want to override the rotational movement in one direction, such as pitching; the minimum is four anchoring lines (<NUM>) when you want to override pitch and roll simultaneously), each of which, at least, is composed of two sublines (200d, 200c), each of which consists of: one (or two) inner pulley(s) (second rotary fixing means (2c) and third rotary fixing means (2d)) and an outer pulley (first rotary fixing means (<NUM>)), which support a cable or anchoring line (<NUM>) composed of three sections, a bottom section (<NUM>) that reaches a bottom weight (<NUM>) resting on the seabed (<NUM>), another central section (<NUM>) fastened to the central counterweight (<NUM>) and an intermediate section (<NUM>) that joins the other two sections (<NUM>, <NUM>). The central counterweight (<NUM>) is shared by all anchor lines (<NUM>). The bottom section (<NUM>) can be divided into two portions, which are attached to an intermediate buoy (<NUM>); in this case, the lower portion (first portion) of this bottom section (<NUM>) is common to all the sublines hanging from the same protruding structural arm (<NUM>). Two complete anchoring lines <NUM> have been depicted simultaneously in <FIG>, one using a solid line (the one on the right) and the other (the one on the left) using a dashed line.

<FIG> shows a scheme of the geometric principle that regulates the lengths of each section (<NUM>, <NUM>, <NUM>) of the anchoring lines (<NUM>) and justifies that the floating platform (<NUM>) always moves parallel to the initial position thereof. The scheme corresponds to central anchoring sublines (where the floating platform comprises a central well) of a state-of-the-art anchoring system (as defined in <CIT>). This figure is provided to serve as a basis for and facilitate the comprehension of the operation of the anchoring system object of the present invention.

<FIG> shows a scheme of the dynamic principle, with the forces acting on the anchoring lines (<NUM>) when the floating platform (<NUM>) is subjected to a force (Fx) and a bending moment (Mf) originating from the external agents (wind, waves or sea currents). The sum of the tensions on all the anchoring lines <NUM> is always constant (equal to the apparent weight of the central counterweight <NUM>, divided by the cosine of the angle β between the central section <NUM> and the central axis <NUM>); the difference between the tensions of the anchoring lines (<NUM>) is proportional to the applied bending moment and the horizontal force FH that is able to support the floating platform (<NUM>) is proportional to the sine of the angle α between the bottom sections <NUM> of the anchoring lines (<NUM>) and the vertical direction. If the cables of the bottom sections (<NUM>) of the leeward anchoring line (<NUM>) become loose, the platform loses its horizontal position (pitch or roll movements appear).

<FIG> and <FIG> show a basic diagram of the anchoring system, similar to that of <FIG>, in which the intermediate buoys (<NUM>) have been removed, so that the bottom sections (8d, 8c) of the direct subline (200d) and of the cross subline (200c) reach the bottom weight (<NUM>) that is in the seabed (<NUM>). <FIG> shows the floating platform (<NUM>) in its resting position and <FIG> corresponds to the floating platform (<NUM>) when it has changed position (horizontal and vertical) due to the effect of wind and waves.

<FIG> shows an operating diagram of the anchoring system with parallel anchoring lines (<NUM>), in which the bottom sections (<NUM>) are vertical in their resting position (dashed lines). When the floating platform (<NUM>) moves (solid line), the cover of the floating platform (<NUM>) is always kept horizontal.

<FIG> shows an operating diagram of the anchoring system with diverging anchoring lines (<NUM>), in which the bottom sections (<NUM>) do not descend vertically to the seabed (<NUM>), but their layout forms an angle (A) with the vertical. When the floating platform (<NUM>) moves horizontally, it tilts windward. In the first approach it is as if it were rotating around the point of intersection of the two bottom sections (<NUM>). If the floating platform (<NUM>) is a marine wind turbine support, with a tower (<NUM>) and a wind turbine nacelle (<NUM>), the axial component of the weight of the nacelle (<NUM>) (due to the inclination of the tower (<NUM>)) can be made to exactly compensate the thrust of the wind on the blades of the rotor, so that the bending moment is annulled throughout the tower (<NUM>) of the wind turbine (and therefore the bending moments transmitted by the tower (<NUM>) to the floating platform (<NUM>)).

An example of the anchoring system comprising four anchoring lines <NUM> is shown in <FIG> and <FIG>. This version of the anchoring system applies to floating platforms (<NUM>) with an even number of projecting structural arms (<NUM>). In this scheme, the inner pulleys (third rotary fixing means (2d)) of the direct subline (200d) have been eliminated, so that the outer pulley (first rotary fixing means (<NUM>)) also performs the functions of an inner pulley and, of course, the intermediate section (<NUM>) of the direct subline (200d) has also been eliminated. The inner pulley (second rotary fixing means (2c)) of the cross subline (200c) appears to be next to the outer pulley (first rotary fixing means (<NUM>)), but this is an optical effect as said pulley corresponds to the cross subline (200c) of another protruding structural arm (<NUM>) (the opposite arm). Also shown in the are the intermediate pulleys (rotary guiding means (<NUM>)) of the crossed subline (200c) that divert the intermediate sections (<NUM>) of the crossed subline (200c) so that they do not cross the same sections of the perpendicular lines (in the "apparent crossing point", said sections pass at different heights).

<FIG> and <FIG> correspond to the installation phases of a floating platform (<NUM>) stable in the ballast condition (in the figures the floating platform (<NUM>) with four protruding structural arms (<NUM>) has been represented, although it is valid for any such platform)). More specifically:.

<FIG>, <FIG> and <FIG> correspond to a first embodiment of the invention. These figures show a floating platform (<NUM>) that serves as a support for a marine wind turbine, which is stable in its ballast condition, with four anchoring lines (<NUM>). The floating platform (<NUM>) has two main loading conditions: the ballast condition, wherein the floating line (<NUM>) passes through an intermediate point of the floating elements (<NUM>) (which divides them into two parts: a submerged zone (<NUM>) and another emerging or emerged zone (<NUM>), which is only submerged in the operating condition) and the operating condition, wherein the floating line (<NUM>) is already in correspondence with the operating draught (<NUM>) and passes through an intermediate point of the spokes (<NUM>) (distinguishing a submerged radio zone in the operating condition (<NUM>) and another never submerged zone (<NUM>)). The spokes <NUM> are attached to the hull in a shaft which, in this case, comprises a structural ring (<NUM>) having eight rectangular faces (where the four radii (<NUM>) and the four protruding structural arms (<NUM>) meet) and eight other trapezoidal faces joining the rectangular faces. Four protruding structural arms (<NUM>) serve to support the outer pulleys (first rotary fixing means (<NUM>)) and the inner pulleys (only the second rotary fixing means (2c) and not the third rotary fixing means (2d) of the anchoring lines (<NUM>) have been represented). On the structural ring (<NUM>) there is a small truncated superstructure (<NUM>) for the electronic equipment of the floating platform (<NUM>) on which the tower (<NUM>) of the wind turbine rests.

<FIG>, <FIG> and <FIG> show three views of the floating platform (<NUM>), with direct (200d) and crossed (200c) sublines. <FIG> shows a (side) profile view of the assembly, aligned with the spokes (<NUM>) or legs of the floating platform (<NUM>) holding the submerged floating elements (<NUM>). <FIG> shows a front view of the assembly aligned with the protruding structural arms (<NUM>) supporting the outer pulleys (rotated <NUM> ° with respect to the spokes (<NUM>), arranged in the bisectors between the spokes (<NUM>)). <FIG> shows a first arm (12a) and a second arm (12b) belonging to a pair of protruding structural arms (<NUM>) located in the same plane. <FIG> shows a 3D view of the assembly.

The protruding structural arms (<NUM>) comprise a first end (<NUM>) attached to the hull or main structure (<NUM>) of the floating platform (<NUM>) and a second end (<NUM>) projecting outwardly from the floating platform (<NUM>).

<FIG>, <FIG> and <FIG> correspond to a second embodiment of the invention. These figures show a floating platform (<NUM>) that serves as a support for a marine wind turbine, which is not stable in its ballast condition, with four anchoring lines (<NUM>) with direct sublines (200d) and crossed sublines (200c), in which an intermediate pulley (rotary guide means (<NUM>)) of diversion has been included in the intermediate section (<NUM>) of the anchoring lines (<NUM>). In this case the pulley is located horizontally and diverts the cables outwards, to avoid the superstructure (<NUM>) that supports the tower (<NUM>) of the wind turbine. The hull or main structure (<NUM>) is the simplest possible, a simple vertical axis cylinder, divided (conceptually) into three parts: a submerged area (<NUM>), which is always submerged (even in ballast condition), another emerging or emerged area (<NUM>), which is only submerged in the operating condition. (These two parts together constitute the 'hull' of the floating platform (<NUM>)). It also has a never submerged zone (<NUM>), i.e. a part of the hull or main structure (<NUM>) that is out of the water in any load condition (analogous to the top of the spokes (<NUM>) of the floating platform (<NUM>) in the first embodiment). Like the floating platform (<NUM>) of the first embodiment shown in <FIG>, in the second embodiment the floating platform (<NUM>) also incorporates four protruding structural arms (<NUM>) and a small superstructure (<NUM>) on the hull that serves to support the tower (<NUM>) of the wind turbine.

<FIG>, <FIG> and <FIG> depict three views of the floating platform (<NUM>) of four protruding structural arms (<NUM>), respectively in profile, in 3D and front perspective (aligned with the protruding structural arms (<NUM>) of the floating platform (<NUM>)).

<FIG>, <FIG> and <FIG> correspond to a third embodiment of the invention, wherein a floating platform (<NUM>) is shown that serves as a support for a marine wind turbine, which is stable in the ballast condition. According to this third embodiment, the hull or main structure (<NUM>) of the floating platform has an annular geometry, forming a flotation ring (<NUM>). It has a central well, although it is not used as such (it is not used for the passage of counterweight cables). Four protruding structural arms (<NUM>) arise from the submerged hull or main structure (<NUM>). <FIG> is a front view of the assembly (aligned with the protruding pulleys and structural arms (<NUM>)). <FIG> is a side view, rotated <NUM>° (oriented according to the bisector of the arms). <FIG> is a 3D view of the assembly.

Although the proposed anchoring system is valid for any floating platform (<NUM>) (intended to support any type of structure), the present invention is especially indicated for two specific applications, as a support for offshore wind turbines and as a platform for offshore leisure. With regard to the object of the proposed patent (the anchoring system), the main difference between the two applications is the deck area of the floating platform (<NUM>), which causes the outer pulleys to hang from protruding structural arms (<NUM>) arranged radially, which protrude quite a bit from the deck of the floating platform (<NUM>), and on the platforms designed for marine leisure, causes the outer pulleys to hang from very short arms that protrude from the main deck of the platform.

The anchoring system according to the first embodiment of the present invention comprises the following elements:.

In <FIG>, three views of this first embodiment (in which its main elements have been identified) can be seen, with the proposed anchoring system.

In the anchoring system, according to the second embodiment of the present invention, unlike the first embodiment, in the ballast condition the floating platform (<NUM>) is not stable, so it is necessary to use a anchoring ring whose function is to give stability to the platform during the transport from the shipyard to the wind farm.

The main structure (<NUM>) of the floating platform (<NUM>) comprises a vertical axis cylinder, conceptually divided into three parts or zones: a submerged zone (<NUM>) under any load condition in the deepest part of the cylinder; an emerging or emerged zone (<NUM>) (intermediate zone) that is out of the water in the ballast condition and submerged in the operating condition and another never submerged zone (<NUM>) (upper part), which is always above the waterline (<NUM>). In addition, the floating platform (<NUM>) comprises four protruding structural arms (<NUM>) arranged radially (and of course the same number of anchoring lines (<NUM>)). The main structure (<NUM>) comprises a small superstructure (<NUM>) for the electrical equipment of the wind turbine, which also serves to support the tower (<NUM>) of the wind turbine.

In this second embodiment, the floating platform <NUM> is the simplest and most economical (of the three proposed embodiments), but has a different hydrodynamic behavior to the other two embodiments, since having much more floating area it tends to follow the movement of the waves, so its vertical movements are greater than those of the other embodiments; as a counterpart, it is able to capture more energy from the movement of the waves and the profile of the waves remains closer to its design floatation (operating draught <NUM>), so it needs less freeboard than the other platforms.

In <FIG>, three views of this second embodiment (in which its main elements have been identified) can be seen, with the proposed anchoring system with an intermediate pulley (rotary guide means (<NUM>)) horizontal in each intermediate section (<NUM>) of the anchoring cable, which serves to separate the cable from the superstructure (<NUM>).

The anchoring system according to the third embodiment of the present invention is stable in the ballast condition and comprises the following features:.

Three views of this third embodiment (in which its main elements have been identified) can be seen in <FIG>. The direct sublines (200d) do not have inner pulleys (third rotary fixing means (2d)), since the outer pulley (first rotary fixing means (<NUM>)) performs the two functions (inner and outer, to save space) and the cross sublines (200c) use vertical intermediate pulleys (rotary guiding means (<NUM>)) to redirect the cable.

As can be seen in the figures, the reinforced structural ring (<NUM>) is raised so that the cables of the intermediate section (<NUM>) of the cross sublines (200c) pass under the superstructure (<NUM>), between the legs or spokes (<NUM>) of the floating platform (<NUM>). If intermediate pulleys are included in this section to deflect the cable downwards, the reinforced structural ring (<NUM>) could occupy a lower position.

As already described, in the anchoring system of the present invention, on each of the anchoring lines (<NUM>) there is a direct subline (200d) and a cross subline (200c), wherein the inner pulley of the cross subline (200c) is located diametrically opposite the inner pulley of the direct subline (200d). This arrangement forces an even number of anchoring lines (<NUM>) (and protruding structural arms (<NUM>)), and also causes the inner sheave of the direct subline (200d) of a first anchoring line (<NUM>) on a protruding structural arm (<NUM>) to be next to the inner sheave of the cross subline (200c) of a second diametrically opposite anchoring line (<NUM>), albeit on different sides of the protruding structural arm (<NUM>).

On floating platforms (<NUM>) for wind turbines that use protruding structural arms (<NUM>) to hold the pulleys, on each head there are two outer pulleys, a direct inner pulley (which can be omitted) and the crossed inner pulley of the diametrically opposite anchoring line.

Two projections of this anchoring system with four protruding structural arms (<NUM>) can be seen in <FIG> and <FIG>; however, the floating platform (<NUM>) could have a different even number of protruding structural arms (<NUM>).

In this type of anchoring, the intermediate sections (<NUM>) of the crossed sublines (200c) of the anchoring lines (<NUM>) can pass to another side of the floating platform (<NUM>) very close to its central axis (<NUM>) of symmetry; therefore, in the hull or in the superstructure, some holes can be made for these cables. An alternative used in the examples presented above, is to use intermediate pulleys (rotary guide means (<NUM>)) to deflect these cables and pass them under the superstructure (<NUM>) of the floating platform (<NUM>) (or on the outside of its sides).

Depending on the geometry of the floating platform (<NUM>) that the anchoring lines (<NUM>) are going to hold, the anchoring system may need some elements that facilitate its correct operation and that have already been introduced previously. Some of these elements can be seen in <FIG>, others are normal elements in shipbuilding and have not been depicted in the figures. These include, but are not limited to:.

The floating platforms (<NUM>) that serve as a support for a wind turbine have several particularities, among others:.

If the anchoring lines (<NUM>) in the design condition are not vertical (as seen in <FIG>), but slightly divergent (as seen in <FIG>), then, when the floating platform (<NUM>) is dragged by the wind the leeward pulley rises relative to the windward one; as a result, the floating platform (<NUM>) has a pitch angle opposite to the wind force. This pitch angle is proportional to the horizontal displacement of the floating platform (<NUM>) and is barely sensitive to the vertical movement thereof.

This angle causes the weight (Q) of the nacelle (<NUM>) to have an axial component opposite to the force of the wind on the rotor blades, which is proportional to the rotated angle, which in turn is proportional to the horizontal movement of the floating platform (<NUM>), which in turn is proportional to the force exerted by the wind. If these proportionality constants are properly synchronized, the axial component of the nacelle weight (<NUM>) can be made to cancel exactly the wind force, regardless of the wind speed.

In this way the bending moment at the base of the tower (<NUM>) due to the wind could be totally annulled. There would still be the forces and moments due to the waves, but they are lesser forces and moments. As a result:.

On floating platforms (<NUM>) dedicated to marine leisure, the external agent that has the most influence on the comfort of passengers is the effect of the waves. With the anchoring system of the present invention, the rotating movements of the floating platform (<NUM>) are eliminated, the vertical movement has little influence (especially if a semi-submersible floating platform (<NUM>) is used), but the effect of the horizontal movement of the waves remains, which with severe seas can generate important accelerations (up to <NUM>/s<NUM>).

In some applications, an anchoring system with divergent anchoring lines (<NUM>) may be used, producing a pitch opposite to the horizontal movement. This pitch can generate a longitudinal acceleration that opposes the acceleration of the horizontal movement, so that the resulting acceleration is lower than if the floating platform (<NUM>) moves without pitching; this would improve the comfort of the people on board.

A terrestrial analogy of this horizontal movement and of inverse pitch would be the movement of a swing or a hammock, which has great movements and turns, but does not generate the sensation of accelerations. In fact, the accelerations remain perpendicular to the surface of the deck of the floating platform (<NUM>) (perpendicular to the surface of the seat, in the case of the swing).

The operating scheme would be similar to that of <FIG>, but with an angle (A) of divergence somewhat greater than that shown in this figure.

A difficulty that appears is that the cancellation of longitudinal accelerations can only be achieved for a relatively small range of waves, for example this cancellation can be achieved for waves between <NUM> and <NUM><NUM>;it is then a question of tuning these periods with the periods of the most likely waves. This tuning depends on:.

The cable of the anchoring line (<NUM>) is quite long, measuring at least the draught in the area of operation, plus the length of the protruding structural arms <NUM> (usually between <NUM> and <NUM>), plus twice the height between the pulleys and the sea surface, plus twice the maximum vertical travel of the floating platform <NUM> (maximum tidal height + wave height), plus <NUM>% of the draught of the sea in the installation area, plus the margin that is deemed convenient.

In some applications, the bottom sections (<NUM>) do not reach the sea bed or bottom (<NUM>), but are fastened to an intermediate buoy (<NUM>) located relatively close to the sea surface and which is anchored to the sea floor (<NUM>) by means of chains or cables, so that in case of wear only the upper part of the cable, which is the most worn (and which is also the most accessible), has to be changed.

The length of the detachable cables must be such that, with the greatest foreseeable movements of the floating platform (<NUM>), the buoys (<NUM>) never approach the outer pulleys (first rotary fixing means (<NUM>)); if touched, a major breakdown could occur. The material of the anchoring lines (<NUM>) may be any suitable for these applications, including but not limited to:.

One of the advantages of the anchoring system of the present invention is the ease of transport, installation and uninstallation of the platforms equipped with this anchoring system.

The installation procedure of the floating platform (<NUM>) is described in some detail below.

In the ballast condition, the submerged flotation elements (<NUM>) of the platform float at half height, giving the floating platform (<NUM>) all or part of the stability it needs for transport. The existence of a buoyancy reserve (materialized in the emerging or emerged zone (<NUM>) of the floating elements (<NUM>)), allows the floating platform (<NUM>) to remain stable throughout transport, despite the pitching movements produced by the waves.

As already mentioned, in the case of the second embodiment of the anchoring system, in its condition of ballast, to guarantee its stability during transport the floating platform (<NUM>) also needs to be anchored to a anchoring ring.

Before moving the floating platform (<NUM>), the bottom anchors of the anchoring lines (<NUM>) are prepared. To do this, the bottom weights (<NUM>) are placed in their position, which can be of any type:.

In these bottom weights (<NUM>), the common part (the first portion or lower portion) of the bottom sections (<NUM>) of the anchoring lines (<NUM>) that in turn secure the intermediate buoys (<NUM>) is fastened or fixed. The buoys (<NUM>) are levelled, so that they are all at the same depth and at the same distance from the central axis (<NUM>) of the floating platform (<NUM>).

This operation can be performed at the same time as the platform is built.

To transport the floating platform (<NUM>), a tugboat is enough to drag the floating platform (<NUM>) and the counterweight (<NUM>) to the wind farm. Optionally, the counterweight (<NUM>) may be positioned just below the floating platform (<NUM>) (held slightly by the central portions (<NUM>) of the sublines (200c, 200d) of the anchoring lines (<NUM>)) and towed together. During transport, all ballast tanks or flood chambers of the floating platform (<NUM>) and of the counterweight (<NUM>) are kept completely empty. In this condition, the counterweight (<NUM>) has a slightly positive buoyancy, with a small freeboard with respect to its strut.

The first phase of the installation is very simple, just place the floating platform (<NUM>) on top of the anchors, with the counterweight (<NUM>) under the center of the floating platform (<NUM>), as can be seen in <FIG>. At this stage it is not necessary to resort to any external stabilization system, since both the floating platform (<NUM>) and the counterweight (<NUM>) are stable per se.

Next, the upper portions (second portions) of the bottom sections (<NUM>) of the anchoring lines (<NUM>) are fastened to the intermediate buoys (<NUM>). The cables are prepared with the length they must have in the operating condition, so when they are hooked they will be untensioned (geometrically there is excess cable in this condition). To tension them, the floating platform (<NUM>) is moved slightly from its vertical position on the anchors (with the tug that has transported it), or the wind is allowed to laterally drag the floating platform (<NUM>) until these cables are slightly tensioned.

One of the tanks or flood chambers of the counterweight (<NUM>) is filled, so that it has a slightly negative buoyancy. The counterweight (<NUM>) begins to submerge and the tension of the cables returns the floating platform (<NUM>) to its position on the bottom anchors. With the floating platform (<NUM>) in place, ballast tanks or flood chambers of the counterweight (<NUM>) continue to be filled; as a result, the floating platform (<NUM>) gradually sinks dragged by the increasing weight of the central counterweight (<NUM>). In this phase, the floating platform (<NUM>) is in the situation shown in <FIG>:.

As the floating platform (<NUM>) sinks, there is a time when the floats or floating elements (<NUM>) are fully submerged. At that time, the stability of the floating platform (<NUM>) almost disappears (or is drastically reduced). This is not a problem, since the tension of the cables has already reached more than <NUM>% of their nominal tension and are able to provide the floating platform (<NUM>) with all the stability it may need.

When all the ballast tanks or flood chambers of the counterweight (<NUM>) are fully filled with water, the floating platform (<NUM>) is almost operational, in general it will float a little above its design floatation (as it must have a certain safety margin in terms of its buoyancy). At this moment it is enough to introduce some ballast water into one of its tanks, so that the platform floats exactly as it was planned in its operating condition.

The assembly now has the appearance shown in <FIG>. At this moment, the only thing missing is to make the electrical connections of the generator with the wind farm transformation plant, so that the wind turbine can operate normally.

To uninstall the floating platform (<NUM>), just follow the inverse process, that is:.

As this tank (the at least one flood chamber of the floatation elements (<NUM>)) is emptied, the floating platform (<NUM>) begins to lift (at the same time as the counterweight (<NUM>)). When the floating elements (<NUM>) reach the sea surface, the floating platform (<NUM>) regains full stability. When the cables begin to lose tension, the floating platform (<NUM>) will be dragged laterally by the wind until the counterweight (<NUM>) reaches the sea surface.

When the ballast tanks (flood chambers) of the counterweight (<NUM>) are completely empty (and the counterweight (<NUM>) has sufficient positive buoyancy), the bottom sections (<NUM>) of the intermediate buoys (<NUM>) are released and the floating platform (<NUM>) is ready to be moved to another location (or to port, for periodic maintenance operations).

Thus, the anchoring system for marine floating platforms (<NUM>), object of the present invention, is preferably formed by four or six anchoring lines (<NUM>), arranged radially around a common point (<NUM>) of the floating platform (<NUM>), each of which is formed by two anchoring sub-lines (200c, 200d) that can include the following elements:.

The anchoring system of the present invention may also include other auxiliary elements, common to conventional anchoring systems and which may assist in the installation/uninstallation maneuver of the floating platform (<NUM>) at its place of operation, such as winches, pinwheels, bollards or other elements typical of any traditional anchoring system.

Each anchoring line (<NUM>) has a direct subline (200d) and a cross subline (200c), whose inner sheave (second rotary fastening means (2c)) is located diametrically opposite the outer sheave (first rotary fastening means (<NUM>)). The anchoring system has an even number of protruding structural arms (<NUM>) and the corresponding anchoring lines (<NUM>) are arranged in diametrically opposed positions two by two.

In the design position, at rest and with calm sea, the bottom sections (<NUM>) of the anchoring cable of all the anchoring sublines (200c, 200d) may be vertical (and parallel to each other).

Alternatively, the bottom section (<NUM>) of all the anchoring sublines (200c, 200d) may be slightly divergent, i.e. the anchoring point of the anchoring cable on the bottom weights (<NUM>) is more horizontally spaced from the central counterweight (<NUM>) than the outer pulley (first rotary fastening means (<NUM>)).

The floating platform (<NUM>) may comprise the following elements:.

The hull or main structure (<NUM>) of the floating platform (<NUM>) has two main load conditions: a transport condition, in which all of its ballast tanks are empty and float freely with a characteristic waterline (<NUM>), and an operating condition, in which all of the anchoring lines (<NUM>) are connected to the seabed (<NUM>) and bear the net weight of the central counterweight (<NUM>). Some of its ballast tanks may be fully or partially filled so that their waterline (<NUM>) matches the design waterline (operating draught (<NUM>)).

According to a possible embodiment, the floating platform (<NUM>) comprises the following elements:.

According to another possible embodiment, the floating platform (<NUM>) comprises the following elements:.

According to another alternative embodiment, the floating platform (<NUM>) comprises the following elements:
four arms (and therefore four anchoring lines and four legs). The main and characteristic elements of its geometry are:.

For those floating platforms (<NUM>) that are stable per se in the ballast condition, the following simplified sequence of installation phases can be followed:.

At this time, the floating platform (<NUM>) is fully operational.

For those floating platforms (<NUM>) that are stable per se in the ballast condition, the following simplified sequence of uninstallation phases can be followed (inverse to the sequence of installation phases described above):.

Claim 1:
Anchoring system comprising a floating platform (<NUM>) and at least one pair of anchoring lines (<NUM>), configured to fix or anchor the floating platform (<NUM>) to the seabed (<NUM>) by means of at least one bottom section (<NUM>) of each anchoring line (<NUM>), wherein each anchoring line (<NUM>) also comprises a central section (<NUM>) attached to a counterweight (<NUM>), wherein each pair of anchoring lines (<NUM>) comprises two anchoring lines (<NUM>) arranged in a plane that passes through a central axis (<NUM>) of the floating platform (<NUM>), and located respectively on one side and the other of the central axis (<NUM>) of the floating platform (<NUM>), wherein the anchoring system comprises at least one first rotating fixing means (<NUM>) for each anchoring line (<NUM>), where each first rotating fixing means (<NUM>) is fixed to a first point of the floating platform (<NUM>) and is configured to fix each anchoring line (<NUM>) to the floating platform (<NUM>) at said first point of the floating platform (<NUM>), allowing the sliding of the anchoring line (<NUM>) along said first rotary fixing means (<NUM>), characterized in that:
- each anchoring line (<NUM>) comprises at least one direct subline (200d) and one cross subline (200c), each comprising its own anchoring cable or chain, wherein each direct subline (200d) runs from the first rotary fastening means (<NUM>) to the counterweight (<NUM>) without passing through the central axis (<NUM>) of the floating platform (<NUM>), and wherein each cross subline (200c) runs from the first rotary fastening means (<NUM>) to the counterweight (<NUM>) through the central axis (<NUM>) of the floating platform (<NUM>);
- wherein the system comprises at least one second rotary fastening means (2c) for each anchoring line (<NUM>), wherein each second rotary fastening means (2c) is fixed to a second point of the floating platform (<NUM>) and is configured to fasten each cross subline (200c) of each anchoring line (<NUM>) to the floating platform (<NUM>) at said second point of the floating platform (<NUM>), allowing sliding of the cross subline (200c) along said second rotary fastening means (2c), so that each cross subline (200c) runs from the first rotary fastening means (<NUM>) to the counterweight (<NUM>) first through the central axis (<NUM>) of the floating platform (<NUM>) and secondly sliding along the second rotary fastening means (2c).