FLOATING STRUCTURE AND METHOD OF INTALLING SAME

Abstract

Floating construction comprising: a flotation base, comprising at least one essentially hollow body selectively fillable with ballast, where the maximum horizontal dimension of the flotation base is greater than the maximum vertical dimension of the floating base; a building supported by said flotation base preferably comprising a telescopic tower; downward impelling means; and at least three retaining cables the corresponding upper ends of which are attached to said flotation base, preferably in peripheral positions of the flotation base, and the corresponding lower ends of which are attached to said downward impelling means, such that said retaining cables are taut and apply a downward force on said flotation base that increases the stability thereof. And the installation method for this floating construction.

Claims

1. Floating construction comprising: a flotation base including at least a body comprising at least a cavity selectively Tillable with ballast, said flotation base having a maximum horizontal dimension and a maximum vertical dimension, wherein the maximum horizontal dimension of the flotation base is greater than the maximum vertical dimension of the flotation base, the flotation base, further comprising a central vertical axis, at least one shaft supported by said flotation base, at least three retaining cables, the at least three retaining cables comprising corresponding upper ends and corresponding lower ends, wherein the corresponding upper ends are attached to said flotation base such that said at least three retaining cables are tensioned and exert on said flotation base a downward force; at least one massive element suspended from said at least three retaining cables and completely submerged, located below the flotation base and raised above the seabed, wherein the corresponding lower ends of said at least three retaining cables are attached to said at least one massive element, and wherein at least three retaining cables are inclined with respect to the central vertical axis, the corresponding upper ends being farther from the central vertical axis of the flotation base than the corresponding lower ends.

2. (canceled)

3. Floating construction according to claim 1, wherein: said at least one shaft is telescopic and comprises at least two segments, including a base segment and a head segment.

4. Floating construction according to claim 1, further comprising at least one stay, comprising an upper end and a lower end, wherein the upper end is joined to the at least one shaft and the lower end is joined to the flotation base, and wherein the at least one said stay is inclined with respect to the vertical such that the lower end is farther from the central vertical axis of the flotation base than the upper end.

5-13. (canceled)

14. Floating construction according to claim 1 wherein said at least one massive element comprises at least a box comprising at least a cavity fully or partially Tillable with ballast material.

15. Floating construction according to claim 14, wherein said at least one massive element comprises means for adjusting the volume and/or weight of the ballast material contained therein.

16. Floating construction according to claim 4, wherein at least one of said at least one massive element is self-buoyant in an unballasted condition or in at least one partially ballasted condition.

17-19. (canceled)

20. Floating construction according to claim 1, wherein at least one of said at least one massive element can be provisionally abutted to the flotation base.

21. (canceled)

22. Floating construction according to claim 1, wherein the flotation base comprises at least one extensor arm projected laterally outward from the flotation base, and wherein at least one of said at least three retaining cables is attached by at least one of the corresponding upper ends to the at least one extensor arm.

23-37. (canceled)

38. Method for installing a floating construction according to claim 1, comprising the following steps: a) fabricating the flotation base on-shore or in-shore, b) fabricating the at least one shaft in dry dock, c) forming on-shore or in-shore a transport unit, buoyant and free standing, that comprises the flotation base and the at least one shaft, according to the following sub-steps: c1) placing the at least one shaft and the object on the flotation base, c2) attaching the at least one extensor arm to the flotation base, d) transporting in a self-buoyant manner, using tug boats, said transport unit, the flotation base remaining semi-submerged and the at least one shaft fully emerged during transport; further comprising, after step a) the steps: e) attaching the corresponding upper ends of said at least three retaining cables to the flotation base, f) attaching the corresponding lower ends of said at least three retaining cables to said at least one massive element; further comprising, before step d), the step: g) placing the flotation base on a body of water; further comprising, after steps e) and f), the step: h) applying by the at least three retaining cables a downward force on the flotation base generated by said at least one massive element; further comprising, after step d), the step: j) attaching to the floating construction the means for maintaining a lateral position of the floating construction.

39. The method according to claim 38, comprising the step: abutting the at least one massive element that forms part of the transport unit and is transported together with the flotation base and the at least one shaft, and ballasting and lowering from the flotation base the at least one massive element.

40. (canceled)

41. The method according to claim 38, further comprising, after step d), the step: l) ballasting the flotation base to obtain a specific vertical position.

42. The method according to claim 39, further comprising, before step h), the steps: n1) manufacturing on-shore or in-shore said at least one massive element and placing said least one massive element in the body of water, n2) transporting said at least one massive element in a self-buoyant manner, using tug boats, and n3) ballasting said at least one massive element such that said at least one massive element is gradually submerged until said at least one massive element is suspended from the at least three retaining cables.

43. (canceled)

44. The method according to claim 38, wherein said step d) is divided into two steps: a first transportation step prior to step h) to a first working area different, and a second transportation step after step h) from said first working area to a second area.

45. Wind turbine using a floating construction according to claim 1.

46-53. (canceled)

54. The method according to claim 38, wherein the at least one shaft is telescopic and comprises at least two segments, including a base segment and a head segment, further comprising the step: i) extending the at least one shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0103] These and other features and advantages of the present invention will become apparent in view of the following non-limiting description of an embodiment of the invention, made with reference to the accompanying drawings, where:

[0104] FIG. 1 shows a schematic plan view with a partial cross-section of a transportation unit with a shaft in the retracted condition, with wind turbine means;

[0105] FIG. 2 shows a schematic plan view with a partial cross-section of a floating substructure with stabilisation means having a single suspended massive body and chains as lateral means for maintaining its position, with wind turbine means;

[0106] FIG. 3 shows a schematic plan view with a partial cross-section of a floating substructure with stabilisation means having a single suspended massive body and a cable-pile assembly as lateral means for maintaining the position, with wind turbine means;

[0107] FIG. 4 shows a schematic plan view with a partial cross-section of a floating substructure with stabilisation means having a single suspended massive body and chains as lateral means for maintaining the position, with extensor arms and stays, with wind turbine means;

[0108] FIG. 5 shows a schematic plan view with a partial cross-section of a floating substructure with stabilisation means having a single suspended massive body and a cable-pile assembly as lateral means for maintaining the position, with extensor arms and stays, with wind turbine means;

[0109] FIG. 6 shows three schematic plan views with a partial cross-section of the corresponding stages in the installation method for a floating substructure with stabilisation means having a single suspended massive body and lateral means for maintaining the position, with wind turbine means;

[0110] FIG. 7 shows six schematic plan views with a partial cross-section of the corresponding stages in the installation method for a floating substructure with stabilisation means having a single suspended massive body, with wind turbine means;

[0111] FIG. 8 shows a schematic perspective view of a floating substructure with stabilisation means having a single suspended massive body and a flotation base with several bodies, with a non-telescopic shaft and wind turbine means;

[0112] FIG. 9 shows a schematic perspective view of a floating substructure with stabilisation means having a single suspended massive body, with another flotation base with several bodies and stays, with wind turbine means;

[0113] FIG. 10 shows a schematic view of a portion of a floating substructure, specifically a flotation base that includes a pressurised gas chamber and Wells type turbines, as well as extensor arms;

[0114] FIG. 11 shows a schematic perspective view of a floating construction with stabilisation means having a single suspended massive body and a flotation base with a single body that supports three shafts, and on these a rectangular hexahedral platform, and;

[0115] FIG. 12 shows a schematic view of a massive suspended element that incorporates hydrodynamic damping means.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

[0116] With reference to the accompanying figures, all of which show a floating construction which, in installed condition, according to the present invention, comprises: a floating base 2, which includes at least one body comprising at least a cavity 25, the maximum horizontal dimension of which is greater than its maximum vertical dimension; a building supported by said flotation base 2; downward impelling means; and at least three retaining cables 8 the corresponding upper ends of which are joined to said flotation base 2 and the corresponding lower ends of which are joined to said downward impelling means. In addition, in all figures except 8 and 11 the building that forms part of the floating construction comprises a telescopic shaft 3 where the wind turbine means 7 shown are an accessory that is optional and/or interchangeable with other accessories, depending on the use of the floating construction, illustrated only by way of example to describe the embodiments of the invention. In FIG. 8 the shaft is not telescopic. In FIG. 11 the building that forms part of the floating construction comprises three shafts 36 supported directly by the flotation base 2 and an electrical substation 41 supported by said shafts and represented schematically by a rectangular hexahedral platform. Said shafts can have one or several segments. The shafts 36 shown are not telescopic but telescopic shafts can also be used in order to temporarily lower the centre of gravity of the assembly. In any case, the flotation base 2 is large enough to ensure stable self-buoyancy of the assembly comprising the flotation base 2 itself and the corresponding building. In the case of FIGS. 1, 6 and 7, the flotation base 2 has dimensions allowing to ensure the stable self-buoyancy of the assembly comprising the flotation base 2 itself, the telescopic shaft 3 in retracted condition and at least part of the wind turbine means 7 placed on the head of said shaft.

[0117] However, FIG. 1 shows a floating substructure in which said downward impelling means and said retaining cables 8 have not been attached to form the complete floating substructure 1 according to the invention, since it shows stages of the installation method for the floating substructure 1 previous to the installed condition.

[0118] Specifically, FIG. 1 shows a transport unit 9 in a transportation stage of an embodiment of the installation method according to the present invention, where a self-buoyant and free-standing transport unit 9, formed by a floating base 2, a telescopic shaft 3 in folded condition supported by said flotation base 2, and wind turbine means 7 joined to the head segment 32 of said telescopic shaft 3 is towed by a tug boat 28. In the transportation stage shown in FIG. 1, the downward impelling means and the retaining cables 8 are transported separately from said transport unit 9 and attached subsequently to the transport unit 9.

[0119] Reference will now be made to FIGS. 2 to 5, each one of which shows a different embodiment of a floating substructure 1 according to the invention.

[0120] FIG. 2 shows wind turbine means 7 supported by an extended telescopic shaft 3 formed by three tubular segments, that is, a base segment 4 and two superposition segments 5, 32. In this case the two lower segments are made from concrete while the head segment 32 is made from metal. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is semi-emerged and the flotation base 2 is submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). These retaining cables 8 are joined on the end opposite the end attached to the flotation base 2, to downward impelling means that consist in a massive suspended element in the form of a hollow box 13 made from concrete, common to all cables. The interior of the common box 13 is completely filled with ballast material 14, such that the flotation base 2 is at its operational depth. Said cables are deployed at an angle to the vertical, such that the upper end of each cable is farther from the central vertical axis 10 of the shaft than the lower end of the same cable. In this embodiment, the flotation base 2 has different compartments that can be ballasted differentially, allowing to generate a non-uniform distribution of the ballast that counteracts, at least partially, external actions such as waves, sea currents, etc. Specifically, a differential ballasting of various compartments counteracting the inclination caused by the average wind force may be of interest. The ballast material 14 can be a liquid material, a solid material or a mixture of both.

[0121] In this embodiment, the floating substructure 1 further comprises lateral means 16 for maintaining the position by which the floating substructure 1 is attached to the seabed. Said lateral means 16 for maintaining the position comprise three moorings, each of which starts at the peripheral area of said flotation base 2 and hangs down away from the flotation base 2 until reaching and resting on the seabed. In this embodiment, each of these moorings is formed by a long and thick chain, and said assembly of chains, or moorings, prevents or at least limits the lateral movement of the floating substructure 1. Alternatively, said moorings can consist of metal or fibre cables, or other types known in the art, without departing from the scope of the invention.

[0122] The weight of the massive suspended element maintains the retaining cables taut, which together with the substantially triangular arrangement allows the massive element to move substantially together with the floating base, thereby improving the stabilisation effect.

[0123] In this embodiment the retaining cables are designed such that their axis passes approximately through the centre of gravity of the massive suspended element, which improves the behaviour of the assembly as the centre of forces is located near the alignment of said cables. In addition, in this embodiment the retaining cables adopt a sufficient inclination greater than 1 degree, such that the limited inclinations that the floating construction will experience during its operation will not manage to make a retaining cable vertical, which is suitable for preventing slacking phenomena, in which the retaining cables lose tension.

[0124] FIG. 3 represents wind turbine means 7 supported on an extended telescopic shaft 3 formed by two tubular segments, a base segment 4 in this case made from concrete and a head segment 32, in this case metallic. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is emerged and the flotation base 2 is semi-submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). These retaining cables 8 are joined on the end opposite the end attached to the flotation base 2, to a massive suspended element in the form of a hollow box 13 made from concrete, common to all cables. The interior of the common box 13 is completely filled with a specific mix of ballast materials that include liquid and solid materials, such that the flotation base 2 is at its operational depth. The hollow box 13 is operatively connected through means 18 (the cable is not shown due to the view shown) to the flotation base and means to adjust the weight of the massive element by increasing or decreasing the amount of ballast material in it. The retaining cables are deployed at an angle to the vertical, such that the upper end of each cable is farther from the central vertical axis 10 of the shaft than the lower end of the same cable. In this embodiment, the flotation base 2 is not ballasted.

[0125] In this embodiment, the floating substructure 1 further comprises lateral means 16 for maintaining the position by which the floating substructure 1 is attached to the seabed. Said means 16 for maintaining the lateral position comprise a pile anchored to the seabed and a single mooring attached on one end to the common box 13 and on the other end to said pile. As indicated above, the interior of the common box 13 is completely filled with a specific mixture of ballast materials, such that the flotation base 2 is placed at its operational depth, such that the lateral means 16 for maintaining the position are not intended or designed to provide a downward impelling means in order to determine the depth of the floating substructure 1; instead, they only withstand the tensions caused by forces exerted on the floating substructure 1 by external actors, such as waves, sea currents, etc. In any case, the means for maintaining the lateral position can exert certain downward forces that contribute to stability, together with that exerted by the downward impelling means, without departing from the scope of the present invention.

[0126] FIG. 4 shows wind turbine means 7 supported by an extended telescopic shaft 3 formed by three tubular segments, that is, a base segment 4 and two superposition segments 5, 32. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is semi-emerged and the flotation base 2 is submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). Specifically, in this embodiment the flotation base 2 comprises three extensor arms 19 that extend laterally out of said flotation base 2 and from each of said extensor arms 19 leaves a corresponding cable. These retaining cables 8 are joined on the end opposite the end attached to the flotation base 2, to a massive suspended element in the form of a hollow box 13 made from concrete, common to all cables. The interior of the common box 13 is completely filled with a specific mix of ballast materials, such that the flotation base 2 is at its operational depth. Said cables are deployed at an angle to the vertical, such that the upper end of each cable is farther from the central vertical axis 10 of the shaft than the lower end of the same cable. In this embodiment, the flotation base 2 is not ballasted.

[0127] In this embodiment, the floating substructure 1 further comprises lateral means 16 for maintaining the position by which the floating substructure 1 is attached to the seabed. Said lateral means 16 for maintaining the position comprise three moorings (of which only two are visible due to the view shown), each of which starts at a corresponding extensor arm 19 and hangs downward away from the flotation base 2 until resting on the seabed. In this embodiment, each of these moorings is formed by a long and thick chain, and said assembly of chains, due to their weight, prevents or at least limits the lateral movement of the floating substructure 1.

[0128] In addition, the floating substructure 1 includes three stays 20 each of which starts at a corresponding extensor arm 19 and is joined by its other end to the upper end of the base segment 4 of the shaft of the floating substructure 1. In fact, in this embodiment three strands are provided, each of which is attached on one end to the common box 13 and on the other end to the upper end of the base segment 4 of the shaft of the floating substructure 1. Each of said strands passes through a deflection element 21 placed at the free end of a respective extensor arm 19, such that each strand is divided into a bottom segment reaching from an extensor arm 19 to the common box 13 and an upper segment that extends from an extensor arm 19 to the upper end of the base segment 4 of the shaft of the floating substructure 1. Then each of said lower segments forms each of said retaining cables 8, and each of said upper segments forms each one of said stays 20. Said deviation element 21 in this embodiment is a plastic element with a curved face that allows the cable to deflect, adopting a suitable bending radius.

[0129] FIG. 5 shows wind turbine means 7 supported by an extended telescopic shaft 3 formed by four tubular segments, that is, a base segment 4 and three superposition segments. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. From the peripheral area of said flotation base 2 emerge three retaining cables 8. Specifically, in this embodiment the flotation base 2 comprises three extensor arms 19 that extend laterally out of said flotation base 2 forming a spatial layout, and from each of said extensor arms 19 leaves a corresponding cable. These retaining cables 8 are joined on the end opposite the end attached to the flotation base 2, to a massive suspended element in the form of a hollow box 13 made from concrete, common to all cables. The interior of the common box 13 is completely filled with ballast material 14, such that the flotation base 2 is at its operational depth. Said cables are deployed at an angle to the vertical, such that the upper end of each cable is farther from the central vertical axis 10 of the shaft than the lower end of the same cable.

[0130] In this embodiment, the floating substructure 1 further comprises lateral means 16 for maintaining the position by which the floating substructure 1 is attached to the seabed. Said means 16 for maintaining the lateral position comprise a pile anchored to the seabed and a single mooring attached on one end to the common box 13 and on the other end to said pile. As indicated above, the interior of the common box 13 is completely filled with a ballast material 14, such that the flotation base 2 is placed at its operational depth, and such that the lateral means 16 for maintaining the position are not intended or designed to provide a downward impelling means in order to determine the depth of the floating substructure 1; instead, they only withstand the tensions caused by forces exerted on the floating substructure 1 by external actors, such as waves, sea currents, etc.

[0131] In addition, the floating substructure 1 includes three stays 20 each of which starts at a corresponding extensor arm 19 and is joined by its other end to the upper end of the base segment 4 of the shaft of the floating substructure 1. Preferably, the stays 20 are pre-installed, that is, one end of each stay 20 is attached either to the floating base or to the upper end of the base segment 4 of the shaft of the floating substructure 1 before the transportation step, while the rest of the stay 20 is folded and attached to the floating substructure. After the transportation step, each stay 20 is extended and attached on its opposite side either to the upper end of the base segment 4 of the shaft of the floating substructure 1 or to the floating base, respectively.

[0132] Reference is now made to FIGS. 6 and 7, which show schematically three corresponding embodiments of an installation method according to the invention.

[0133] With reference specifically to FIG. 6, view 6(a) shows a transportation unit 9 in a transportation step where said self-buoyant and free-standing transport unit 9, formed by a flotation base 2 with elements 30 for provisional collection of the retaining cables, a telescopic shaft 3 in a retracted arrangement supported by said flotation base 2, and wind turbine means 7 joined to the head segment 32 of said telescopic shaft 3, is towed by a tug boat 28. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). These retaining cables 8 are attached by their end opposite to the end joined to the flotation base 2, to a massive element intended to be suspended at a certain distance from the seabed, thereby acting as downward impelling means, in the form of a box body 13, comprising at least a cavity, common to all cables, the profile of which is the same as that of a central bottom recess in the flotation base 2. In this transportation step said common box 13 is therefore abutting the flotation base 2, housed in said recess, and is transported together with said base. Said common box 13 remains abutting the flotation base 2 in this transportation step because as the common box 13 is hollow and empty, it floats on the body of water, and is therefore carried by the flotation base 2.

[0134] In fact, once the transportation step shown in view 6(a) has finished and before the equilibrium condition shown in view 6(b) is reached, the common box 13 is partially ballasted with a first ballast material 14 until said cables are fully extended.

[0135] View 6(b) then shows the transport unit 9 in said equilibrium condition, with the cables fully extended, and the common box 13 suspended at a certain distance from the seabed, corresponding to its buoyancy point, with the flotation base 2 floating on the water.

[0136] Then, prior to the installed condition shown in view 6(c), lateral means 16 for maintaining the position are attached to the floating substructure 1 by which the floating substructure 1 is anchored to the seabed. Said lateral means 16 for maintaining the position comprise two moorings, each of which starts at the peripheral area of said common box 13 and hangs down away form said common box 13 until resting on the seabed. In this embodiment, each of these moorings is formed by a long and thick chain attached to an anchor on the seabed, and said assembly of chains prevents or at least limits the lateral movement of the floating substructure 1. Alternatively, said means 16 for maintaining the position can be connected to the floating substructure 1 before ballasting the suspended massive element, or can be connected to a different part of the floating substructure 1 such as the flotation base 2.

[0137] The common box 13 is then fully ballasted using a second ballast material 14, such that the flotation base 2 is lowered to its operational depth, compressing the air trapped in the central lower recess of the flotation base 2.

[0138] View 6(c) shows the floating substructure 1 according to the present invention in said installed condition, where the cables are fully extended and under tension, the common box 13 is fully ballasted so that the flotation base 2 is at its operational depth, and the lower central recess in the flotation base 2 contains a compressed air chamber 22 that can increase the buoyancy experienced by the flotation base 2. Regulating the air contained in said chamber 22 can allow regulating the buoyancy force and therefore the depth of the floating substructure assembly 1. This embodiment also incorporates a Wells type turbine 23 in an air passage between said compressed air chamber and the interior enclosure of the shaft, such that the variations in the water depth of said chamber 22 caused by waves can be used to generate power.

[0139] In this case the shaft of the floating substructure 1 is emerged and the flotation base 2 is semi-submerged.

[0140] With reference specifically to FIG. 7, view 7(a) shows the dry dock construction of the flotation base 2. View 7(b) shows a transportation unit 9 in the transportation step, where said transportation unit 9 is self-buoyant and free-standing and is formed by a flotation base 2, a telescopic shaft 3 in a retracted condition supported by said flotation base 2, and wind turbine means 7 joined to the head segment 32 of said telescopic shaft 3; the same view 7(b) shows the independent transportation, simultaneous or otherwise, of a massive element in the form of a concrete box 13, self-buoyant and free standing, that is also towed to the site. Said box 13 has the retaining cables 8 prefitted by provisional collection means 30 for the retaining cables. Said box 13 is partially ballasted from the start of the transportation without this compromising its stable buoyancy, such that the amount of ballast that must be supplied in the final offshore site is reduced.

[0141] Optionally, the transportation unit 9 and the massive element in the form of a concrete box 13 can be transported joined and/or with the connections of the two ends of at least part of the retaining cables 8 already established.

[0142] View 7(c) shows a later step of the installation process in which the retaining cables 8 transported on the massive element have been extended to different lengths, in full or in part, and connected to peripheral points of the flotation base 2.

[0143] View 7(d) shows the ballast process of the concrete box 13, which leads to its gradual fall until it is finally suspended from the retaining cables 8. The weight of the box 13 and the retaining cables 8 that hold it will make the box 13 tend on its own towards its final position with respect to the flotation base 2, which in this case coincides with the central vertical axis 10 of the shaft and of the flotation base 2. However, the process can also be aided by one or more tug boats 28.

[0144] Once the box 13 is suspended from the flotation base 2 by inclined retaining cables 8, the structure will have a great stability and the telescopic shaft 3 will be raised together with the wind turbine means 7, as shown in view 7(e). Finally, view 7(f) shows the installed condition of the floating substructure 1 with the box 13 fully ballasted and the incorporation of means 16 for maintaining the lateral position. In this case the flotation base 2 is ballasted partially to adjust the depth of the structure. The ballast material 14 is preferably liquid and its volume adjustable, allowing to adjust as required the depth of the assembly according to circumstances, particularly wind and waves.

[0145] In the embodiment according to the invention of FIGS. 6 and 7, the massive element, abutting or transported independently, provides the required stability through the retaining cables 8 during the ballasting process of the flotation base 2, even if the flotation base 2 is fully submerged. For this reason, the installation process can be performed without having to use flotation stabilisation means 27.

[0146] FIGS. 8 and 9 show corresponding embodiments of a floating substructure 1 for a wind turbine according to the present invention, in which the flotation base 2 is formed by a plurality of hollow bodies. Specifically, FIG. 8 shows an embodiment of a floating substructure 1 for a wind turbine according to the present invention in which the flotation base 2 is formed by a main hollow body and two additional hollow bodies, all hollow bodies joined to each other by lattice type structures; FIG. 9 shows an embodiment of the floating structure 1 for a wind turbine according to the present invention in which the flotation base 2 is formed by a main hollow body and three additional hollow bodies, each one of the additional hollow bodies being joined to the main hollow body by a bar type structure which in this case is also formed by a prismatic hollow body.

[0147] In the embodiment of FIG. 8, the main hollow body is disc shaped and supports on it a non-telescopic tubular shaft 40 which in turn supports the wind turbine means 7, and the additional hollow bodies are arranged such that they form a triangular layout with the main hollow body. In this embodiment each one of the retaining cables 8 starts at a different hollow body and they meet at a massive element acting as the downward impelling means. In addition, the retaining cables 8 all have the same length, such that said massive element is displaced with respect to the central vertical axis 10 of the shaft and substantially coincides with the central vertical axis 11 of the flotation base 2 with three bodies that is displaced with respect to the central vertical axis 10 of the shaft.

[0148] In turn, in the embodiment of FIG. 9 the main hollow body is disc shaped and supports the shaft of the floating substructure 1, and the additional hollow bodies are arranged around said main hollow body at positions equidistant to each other and to said main body. In this embodiment the retaining cables 8 start at each of the different hollow bodies and meet at a massive element acting as the downward impelling means. In addition, the retaining cables 8 all have the same length, such that said massive element is displaced substantially on the central vertical axis 10 of the shaft and substantially coincides with the central vertical axis 11 of the flotation base 2.

[0149] The floating substructure 1 of this embodiment also comprises three stays 20, each of which arise from each one of the additional hollow bodies and are joined to the upper end of the base segment 4 of the shaft of the floating substructure 1. Preferably the lower end of a stay 20 of a floating construction according to the present invention will be joined to the flotation base 2 of the floating structure at a position close to or aligned with the point of union of the upper end of one of the retaining cables 8 to the flotation base 2.

[0150] In this embodiment the segments of the telescopic shaft 33 are formed by prefabricated half-segments which, joined at vertical joints 38, form cylindrical segments of the shaft. Similarly, formed between said cylindrical segments are horizontal joints 37 along the shaft.

[0151] The tower segments formed by half-segments can be preassembled in dry dock and/or in port to form full segments, and then the full segments attached to the flotation base 2, as an intermediate step also applicable to other offshore substructures that use telescopic towers such as that described in the present invention.

[0152] Lastly, FIG. 10 shows a detailed view of an embodiment of a floating substructure 1 according to the present invention, specifically a flotation base 2 with extensor arms 19 that includes a pressurised gas chamber 22 and Wells type turbine 23 to harness wave power.

[0153] More specifically, the peripheral wall of the flotation base 2 is extended downward such that a cavity facing downward is defined. This cavity initially contains air which is trapped when the flotation base 2 is placed in the body of water of the site. In addition when the flotation base 2 is submerged said trapped air is compressed, forming said pressurised gas chamber 22. Alternatively or additionally, air or any other pressurised gas can be introduced in said pressurised gas chamber 22. In addition, the flotation base 2 is compartmentalised. Each compartment has an opening in the end wall and, in corresponding with each such opening, a Wells type turbine 23. In addition, the compartments also have an opening in each partition wall between compartments. The partitions between compartments also extend downward such that said pressurised gas chamber 22 is also compartmentalised.

[0154] The power generation system of a Wells type turbine 23 is based on OWC (oscillating water column) technology, which relies on the pressure changes generated by waves on the air chamber 22 that drive air through the Wells type turbines 23.

[0155] The presence of Wells type turbines 23 in the embodiments of the present invention to generate power from waves in which the floating construction is a floating substructure 1 for a wind turbine is particularly appropriate as all the infrastructure provided for evacuating the power generated by the wind turbine is already present.

[0156] In addition, the pressurised gas chamber 22 can comprise means for controlling and regulating the volume and/or pressure of the gas contained in said pressurised gas chamber 22, in order to regulate or help regulate the depth of the floating substructure 1 and to adjust or help adjust the resonant frequency of the gas chamber 22 to improve the efficiency of the oscillating water column system.

[0157] With reference again to FIGS. 1 and 2, an embodiment of a method for installing a floating substructure 1 for a wind turbine according to the present invention thus comprises the following steps: [0158] fabricating a flotation base 2 in the form of a hollow disc; [0159] placing the flotation base 2 on the body of water at the site; [0160] fabricating on dry dock three segments of a telescopic shaft 3, including a base segment 4 and a head segment 32; [0161] forming a transportation unit 9, buoyant and free standing, which comprises the flotation base 2, the telescopic shaft 3 in a retracted condition centrally supported on said flotation base 2 and wind turbine means 7 supported on the head segment 32 of said telescopic shaft 3; [0162] towing in a floating manner said transportation unit 9 to a first working site different from the final site, the flotation base 2 remaining semi-submerged and the telescopic shaft 3 being in a retracted condition and completely emerged; [0163] securing the upper end of the retaining cables 8 to the flotation base 2; [0164] securing the lower end of the retaining cables 8 to downward impelling means in the form of a hollow box 13 common to all cables; [0165] towing in a floating manner the assembly formed by said transportation unit 9, said retaining cables 8 and said common box 13 from said working area to the site, the flotation base 2 remaining semi-submerged and the telescopic shaft 3 being in a retracted condition and completely emerged; [0166] applying, using the retaining cables 8, a downward force on the flotation base 2 generated by said common box 13 as it is ballasted, such that the flotation base 2 is lowered to its operational level; [0167] extending the telescopic shaft 3 together with the wind turbine means 7; [0168] attaching to the substructure lateral means 16 for maintaining the position in the form of chains, specifically:

[0169] joining a first long and thick chain by one of its ends to a first peripheral point of said flotation base 2 such that said chain is extended, moving away from the flotation base 2 until it rests on the seabed, and

[0170] joining a second long and thick chain by one of its ends to a second peripheral point of said flotation base 2 such that said chain is extended, moving away from the flotation base 2 until it rests on the seabed,

[0171] said first and second peripheral points being placed diametrically opposite each other with respect to the flotation base 2; and [0172] regulating the ballast of said common box 13 such that the flotation base 2 maintains its operational depth after attaching said chains to said flotation base 2.

[0173] As shown in FIGS. 1 and 2, the lateral means 16 for maintaining the position comprise two long and thick chains starting at the flotation base 2 at diametrically opposite points. However, a person skilled in the art will understand that the number of chains and their corresponding starting points in the flotation base 2 may vary to meet specific requirements.

[0174] Said first working area is a sheltered area with a great depth.

[0175] FIG. 12 shows a massive element incorporating hydrodynamic damping means 39 intended to reduce the movement of the floating construction. Specifically, the figure shows hydrodynamic damping means in the form of a horizontal plate, often referred to as a heave plate, placed on the base of the massive element that protrudes laterally. Said heave plate will reduce vertical movements. In this specific case, although it is not essential, said heave plate also has a number of orifices 40. Said orifices 40 can incorporate means for controlling the water flow such that flow is allowed in one direction but prevented in another (for example, in this embodiment to oppose upward movement more than downward movement).

[0176] This embodiment also incorporates hydrodynamic damping means 39 in the form of substantially vertical elements attached laterally to the side of the massive element. Said elements interact with the water surrounding the massive element and reduce its horizontal movement, increasing its contribution to the stability of the floating construction. Said substantially vertical elements can have the form of a plate or solid wall, preferably made from concrete or metal, or in the form of a laminar element as a sail made from fibre materials, textiles or other materials known in the art.

[0177] Other types of hydrodynamic damping can also be used without departing from the scope of the invention, even those based on growth of algae or other organisms in the suspended massive element, and/or other means known in the art that enhance friction and/or mobilisation of the water that surrounds said massive suspended element.

[0178] This embodiment also shows that the retaining cables are designed such that two ends of different retaining cables start at approximately the same point, allowing a perfect triangulation of the cables and therefore a more rigid behaviour of the connection between the flotation base and said massive element. Said triangulations can be generated in a horizontal and in a vertical sense (as shown in the figure), in order to rigidify the union between the two elements against torsion (that is, rotations about the vertical axis of the floating construction).

[0179] Naturally, the principal of the present invention remaining the same, the embodiments and constructive details may vary considerably from those described and represented for illustration purposes and in a non-limiting sense, without departing from the scope of the present invention as defined in the accompanying claims.

[0180] For example, by way of illustration, in light of the teachings of this document it would be obvious for a person skilled in the art that the turbine means could comprise up-wind or down-wind turbines, as well as any number of blades, not being limited to three blades as shown for illustration purposes.

[0181] Also for purposes of illustration, although the present document refers to cables used to connect the downward impelling means and the flotation base, a person skilled in the art will understand that instead of cables these can be chains, rods, slings or the like, without departing from the scope of the invention.

[0182] Also for purposes of illustration, a person skilled in the art in view of the teachings of the present document will find it obvious that the lateral extensions referred to herein as arms can be coupled or even integrated in a lateral extension in the form of a continuous crown or as crown arcs, or in any other type of structure, without departing from the scope of the invention. Similarly, it will be obvious for a person skilled in the art in view of the teachings of the present document that although circular shapes are preferred for many of the elements comprised in the invention such as the shafts, hollow bodies or boxes, many other shapes are possible without departing from the scope of the invention, such as square or rectangular shapes, or regular and irregular polygons.

[0183] Known techniques may be used to regulate the volume and/or weight of the ballast material of the massive elements, such as those used in submarines to control depth.