WO2018151594A1

WO2018151594A1 - Framework for installing an offshore windmill

Info

Publication number: WO2018151594A1
Application number: PCT/NL2018/050100
Authority: WO
Inventors: Jan Lanser
Original assignee: Marine Innovators B.V.
Priority date: 2017-02-14
Filing date: 2018-02-13
Publication date: 2018-08-23
Also published as: NL2018377B1; NL2018377A; EP3583269A1

Abstract

The invention is directed to an immersible framework, suited for installing a windmill on the bottom of a body of water. The framework comprises of a fixed part (3a) comprising anchoring means (8) suitable for anchoring the framework to the bottom of a body of water and supporting means (7a) suitable for letting the framework rest at the bottom (65) of the body of water Further comprising a tiltable part (4) comprising connecting means (35) for connecting a windmill to the tiltable part (4). The tiltable part (4) is rotatably connected to the fixed part (3a) by means of a substantially horizontal axis (21).

Description

FRAMEWORK FOR INSTALLING AN OFFSHORE WINDMILL

The invention relates to an immersible framework for installing a windmill or a foundation for a windmill at the bottom of a body of water.

US 2016052606 describes a vessel that is suitable for installing a foundation for a windmill at sea. Such vessels are also sometimes called Offshore Wind Turbine Installation and Ship (OWTIS)". The foundations are positioned vertically on the deck of the vessel. With the help of a crane, these foundations can be positioned at the bottom of a body of water. A disadvantage of the use of such a vessel is that the positioning of the foundation can only take place when the swell is not too high. Such ships are moreover very big and complex, as can be seen in figure 1 of this published document. Huisman Equipment B.V. has developed a so-called Wind Turbine Shuttle (WTS). This is a floating vessel of the catamaran type, which is capable of

simultaneously transporting two vertically positioned windmills, and of installing these onto a foundation that has previously been immobilised at the bottom. An advantage of this method is that the windmills do not have to be positioned vertically in situ. The disadvantage, however, is that first a foundation must be placed at the bottom. Moreover, it is difficult to position the windmill correctly from the floating vessel on such a basic construction. To do this, one must make use of an active positioning system. Nevertheless, in cases of unfavourable weather conditions, the fixation of the windmill on its foundation shall be difficult to achieve.

EP 2568082 describes a method for installing a foundation for a windmill at the bottom of a body of water, in which the use of such a big and complex vessel can be avoided. This can be achieved by towing the foundation, consisting of a framework structure comprising flotation bodies, to the selected location. By subsequently removing the air at the lower side of the foundation, the latter will tilt into the desired vertical position. After this position has been reached it is also possible to remove the air from the remaining flotation bodies, which results in the foundation sinking to the bottom of the body of water. Subsequently, the foundation is coupled to an already positioned basic construction. A disadvantage of this method is that first a basic construction should be installed at the bottom of the water. It is, moreover, difficult to correctly position the floating and immersible foundation on such a basic construction.

WO 14187977 describes a floating windmill that is towed to the desired location in a horizontal and floating position, after which the windmill is tilted into the eventual vertical floating position. The tilting can be achieved by filling

compartments in the windmill with water. Because compartments of flotation bodies that are situated closer to the turbine and the blades are filled with gas, the windmill will tilt into the desired vertical position. The floating windmill is then connected with the bottom of the water by means of anchors and anchor chains. The present invention does not relate to such a floating windmill.

GB24071 14 describes a barge on which a vertically positioned wind turbine is connected to. At the location where the windmill is to be placed on the sea bed by pivoting the windmill at a point at its lower end. In this way the windmill erects to a vertical position. A disadvantage of this method is that the weight of the windmill foundation has to be high in order to compensate the weight and the arm of the other end of the windmill. This adds complexity and additional weight to the windmill to be installed. A further disadvantage is that method is difficult to perform when the waves are high.

WO2009005357 describes the installation of a windmill having a telescopic mast. Once the mast is in its vertical position air is introduced into the telescopic mast resulting in that the inner telescopic part is pushed out of the outer telescopic part thereby increasing its length. When erecting the telescopic mast use is made of a reusable buoyancy element. Erecting is performed by means of cables which are pulled by tow boats. A disadvantage of such a method is that the control over the mast when being erected is small. Wind and waves and varying pulling tension on these cables may make such a procedure prone to failure.

In WO2010/138622 a method is described where the foundation of the windmill is first installed. The mast, generator and blades are subsequently positioned on this foundation. The mast, generator and blades are present on a barge in a horizontal position. The lower end of the mast is subsequently lowered from the barge to a point of the pre-installed foundation. Once this lower end is coupled with the pre-installed foundation the mast is erected further by having the barge push the mast at sea level. The mast will pivot and end up in a vertical position. A problem with this method is to discharge the mast from the barge under and angle into the sea. The centre of gravity of such a mast/generator/blades configuration will be nearer the generator, thereby making it difficult to lower the lower end of the mast under an angle towards the pre-installed foundation.

Secondly the lower end will have to find the pivot point at the pre-installed foundation. The description described rails and winches on the pre-installed foundation. This will increase the complexity of every single foundation of every single windmill. Thirdly the mast will have to be further erected. Because the barge itself is supposed to push the mast upright one can imagine that this can only be performed under very calm sea conditions.

The aim of the present invention is to provide a means for installing a windmill at the bottom of a body of water which does not have the above disadvantages. This aim is realised using the following framework.

Immersible framework, suited for installing a windmill on the bottom of a body of water whereby the framework comprises of a fixed part comprising anchoring means suitable for anchoring the framework to the bottom of a body of water and supporting means suitable for letting the framework rest at the bottom of the body of water, and

a tiltable part comprising connecting means for connecting a windmill or at least a foundation of a windmill to the tiltable part, wherein the tiltable part is rotatably connected to the fixed part by means of a substantially horizontal axis.

The invention is also directed to a method for installing a windmill on the bottom of a body of water, whereby the windmill comprises a foundation that is suitable for being anchored to the bottom, and whereby the foundation is connected or can be connected with a mast comprising a generator and blades, and whereby the method comprises the following steps:

(a) connecting the foundation, possibly connected with the mast comprising the generator and the blades, to the tiltable part of the framework according to the invention,

(b) immersing the obtained framework from step (a),

(c) positioning and anchoring the framework to the bottom of the body of water,

(d) moving the foundation from a horizontal position or from a position that forms an angle with the bottom, to a vertical position by means of a rotation around the substantially horizontal axis of the tilted part of the framework and

(e) fixing the foundation onto the bottom.

The immersible framework is advantageous compared to the framework used in WO2010/0138622 in that the framework is reusable for placing a next windmill. Once a windmill is placed the framework can return to the sea level to collect a next windmill for placement. In the prior art method the pre-installed foundation remains at the sea bed as part of the installed windmill. A next advantage is that less power is required to erect the windmill using this framework. This because erecting may take place while the framework is anchored to the seabed. This allows one to make use of the buoyancy of the tiltable part and/or the part of the mast which is immersed. A next advantage is that once the framework is anchored to the seabed the windmill can be correctly positioned accurately at the desired location. Further the weather conditions will have less influence on this method. A further advantage is that an assembled complete windmill including it foundation, mast, turbine and blades can be installed by this method. Compared to the current commercially applied methods the framework according to the invention is advantageous because large Offshore Wind Turbine Installation and Ship (OWTIS)", which are sometimes equipped with a crane installation with a loading capacity of 5000 1 and even up to 10,000 t, can be avoided. By anchoring the framework with attached thereto a windmill or a foundation at the seabed it is possible to position the windmill or the foundation upright, and to anchor them without having to use a floating vessel that is equipped with a big crane. The method can be used with a high degree of automation/mechanisation. The framework can furthermore be used at great depths. The applicant is also of the opinion that the use of the framework is safer than existing methods. This is a result of the fact that the windmill or at least its foundation will only be in the relatively unsafe vertical position in step (d), a step that can be carried out at a safe distance from the operating personnel. A next advantage is that the framework can also be used to remove, decommission, installed windmills.

In this application terms are being used such as horizontal and vertical. These terms relate to the eventual desired vertical position of the windmill after its installation. The term horizontal relates to the position of the elongated direction of the windmill parallel to the horizon of the body of water. The term transverse is used to indicate the direction in the horizontal plane, more specifically the direction that is perpendicular to the course of the floating vessel, and even more specifically perpendicular to the longitudinal direction of the windmill, if present or possibly present. Moreover, the terms tilt/tilting, rotation, and placing in an upright position of the foundation or of the windmill refer to the same movement as can be carried out in step (d). The windmill that can be installed using the method according to the invention comprises a foundation that is suitable for being anchored at or to the bottom of a body of water. The windmill also comprises a mast with a generator and blades that are connected thereto. The generator can convert the rotating movement of the blades into electrical energy. The mast connects the foundation to the generator. The foundation, as it is being referred to in this application, can comprise part of the mast. The foundation can for example comprise a part of the mast which, after installing in step (e), terminates adjacent to the water surface, for example close to and above the water surface. On this foundation, the remaining part of the mast with the generator and the blades can subsequently, in an additional step (f), be installed. In the context of this application an installed and operable windmill is meant to be a windmill that comprises a foundation, a mast, a generator, and blades. The term generator is in this context also meant to refer to a generator housing. Further, the blades will be connected to the rotation axis of the generator by means of a hub. This foundation preferably comprises anchoring means that are driven into the bottom. Examples of such anchoring means are suction anchors. The anchoring means can also be piles or the mast itself which is drilled into the bottom, for example by means of a pile driver. The foundation can be any known foundation for a windmill comprising anchoring means at the bottom, such as the already mentioned framework foundation that is described in EP 2568082. Suitable framework constructions often comprise three or four corners at their bottom side, whereby these corners comprise the said anchoring means. Preferably, the foundation is a so-called mono-pile foundation or a tripod foundation. The mast can have a constant diameter or can have a variable diameter that increases in the direction of the foundation.

In step (d), the foundation is preferably moved from a horizontal position or from a position that forms an angle with the bottom, to a vertical position by rotating it along a substantially horizontal axis. The foundation can be part of a windmill comprising a mast, the generator, and blades. Compartments in the foundation and/or compartments in the mast that can be present are preferably filled with a gas, in such a way that the resulting upward forces allow the rotation to take place. Additional flotation bodies can preferably be attached to the mast, the tiltable part and/or to the generator and which flotation bodies can be used to facilitate the rotation. It is for example possible to carry out part of the rotating movement when the framework is in step (b) lowered to the bottom. By using compartments high up in the mast and/or by using a flotation body that is connected with the mast and/or the turbine, the mast can rotate with reference to an axis of the framework during the immersion.

To make the rotating movement possible, the framework preferably comprises actuators that make the rotating movement possible. The use of these actuators can advantageously be combined with the use of said gas filled compartments and/or flotation bodies.

The anchoring at or into the bottom, as described in step (e), is preferably carried out by means of pile-driving and/or by means of suction anchors. If the anchoring is carried out by means of pile-driving it is to be preferred that piles, or in case of a windmill of the mono-pile type, the mast itself are or is driven into the bottom. This pile-driving can be done using methods that are well known to the man skilled in the art. An example of a suitable driving means is hydro-hammers.

Another possible driving means is the driving device disclosed in EP 2807307, whereby a series of explosions is used to drive the pile or even the mast of the windmill in the case of a windmill of the mono-pile type into the ground. Such a method is also known as the BLUE Piling Technology.

In a first embodiment, a foundation that is not connected to a mast that comprises a generator and blades is connected to the framework in step (a). In an additional step (f), the foundation which is anchored into the bottom of the body of water is connected with a generator and blades and possibly to an additional mast section. A foundation of a windmill of the mono-pile type can easily be anchored using the said driving device by placing the device on top of the mast part of the foundation, and by subsequently driving this part of the mast into the bottom. In cases where the foundation comprises part of the mast it is preferred that the mast extend to just above the water surface, in such a way that the hydro-hammer can be easily operated.

In a second embodiment, the foundation is connected to a mast that comprises a generator and blades in step (a). In this embodiment, the windmill preferably is moved in step (d) from a horizontal position or a position that forms an angle with the bottom to a vertical position by rotating it along a substantially horizontal axis.

This movement preferably is made possible under the influence of an upwardly directed force created by gas filled compartments in the mast of the windmill and/or of flotation means that are connected to the mast or to the foundation and/or to the tiltable part. The flotation means can be removed after step (d) or

(e).

Step (a) can conveniently be carried out on a floating vessel, whereby the windmill comprising the foundation, the mast, the generator, and blades is moved from a storage space for windmills to the framework and connected with the framework. The framework is positioned in a recess in the floating vessel. Step (b) is carried by immersing the framework with the windmill attached to it in a vertical direction from this recess. In the steps (b)-(e), the framework can be connected with the floating vessel by means of cables. Once the framework is anchored at or into the bottom, these cables do not necessarily have to be tensioned. This implies that these steps can be conveniently carried out in situations in which the floating vessel is moving because of for example heavy swell. The storage space for the windmills is preferably a recess in a floating dock vessel or in a harbour quay which recess is filled with water. In such a basin or dock multiple windmills can be stored side-by-side. The windmills are preferably positioned in such a way that the plane in which the blades are positioned extends vertically. The term "extends vertically" refers here to any direction except for the horizontal one. The storage capacity shall of course be higher if the plane extends more in a vertical direction. Slanted storage can also be used to limit the draft of the floating vessel. This way, many windmills, and more specifically windmills of the mono-pile type, can conveniently be stored in the basin. The windmills stored accordingly can then for example be floatingly transported to the framework in order to carry out step (a). The windmills that are being used in step (a) can be assembled on the dock vessel by at least combining the foundation, the mast, the generator and/or the blades with another component from this list, after which the assembled windmill is transported to the storage space.

The above-mentioned floating vessel and dock vessel can comprise a single hull or can be made up of multiple floating vessels, for example pontoons. It is also possible to carry out the same operation on a dock vessel that has been anchored at or into the bottom by means of columns. Such jack-up construction is known. It is also possible to carry out the same operations on a level surface above the water level, like for example a harbour quay. Such a land surface can be connected to the mainland or the island can be a hydraulically filled island. Such land surfaces can comprise basins or docks for the storage of floating windmills and/or coves in which the framework can be positioned to carry out step (a). The obtained framework can floatingly be towed or can be moved using its own propelling system to a position where steps (b)-(e) can be carried out.

After a windmill or a windmill foundation is positioned using the method, the framework can be rigged using winches or for example by filling a number of compartments in the framework with a gas such as air. A combination of winches and filling compartments with air is also possible. Once the water surface has been reached, the framework can conveniently be reused for positioning of a following windmill or foundation.

The invention also relates to an immersible framework that is suitable for use in the method according to the invention. Such a framework comprises connecting means to fix a windmill or at least the foundation of a windmill to the framework, tiltable around a substantially horizontal axis, as well as anchoring means to anchor the framework to the bottom of the body of water, and supporting means so that the framework rests on the bottom of the body of water.

The framework preferably comprises one or more actuators that is or are suitable for moving the windmill connected to the framework, or at least the foundation of a windmill from a horizontal position or a position that forms an angle with the bottom of the body of water to a vertical position. The movement is carried out using a rotation around the substantially horizontal axis. The vertical position is the desired position of the windmill or of its foundation at the bottom of the body of water.

The framework preferably consists of a fixed part that can be anchored to the bottom of the body of water, and of a tiltable part that comprises the connecting means for connecting the windmill or at least the foundation of a windmill, whereby the tiltable part is rotatably connected to the fixed part of the framework around a substantially horizontal axis. This connection can for example consist of a hinge or of any other method known by the man skilled in the art.

The fixed part of the framework can basically be of any shape that permits the rotational movement of the windmill or of the windmill foundation. The form and shape can be for example that of a triangular framework, whereby the corners comprise the anchoring and supporting means, and whereby the axes around which the foundation or the windmill rotates is situated parallel to and adjacent to one of the connecting sides between corners. The framework preferably has a rectangular shape. A rectangular shape offers the advantage that it can be easily combined with other floating vessels, and has more corners with which anchoring means and supporting means can be associated. The fixed part of the framework is thus preferably the next rectangular frame. This rectangular framework comprises two parallel framework beams, two transverse beams, and four corners, whereby the extremities of the framework beams and the extremities of the transverse beams are resiliently and by means of a ball joint connected with each of the corners of the rectangular frame.

The stability of the shape of the rectangular framework can be enhanced by connecting the two framework beams with connecting beams. The corners can optionally also be connected with a diagonally positioned connecting beam in order to further increase the stability of the shape.

The framework beams, the transverse beams, and/or the corners preferably comprise compartments that can be filled with gas and/or water to be able to float or to immerse the framework. The framework beams, the transverse beams, and/or the corners may also comprise additional ballast, preferably having an even higher density than water. Such additional ballast is suitably present in the lower parts of the framework beams, the transverse beams, and/or the corners. Examples of such ballast materials is so-called grouting, also known as concrete. The additional ballast will stabilise the framework when it sinks to the bottom of water, compensates for the buoyancy of the wind mill if present, and increases the gravity base of the construction when it is connected to the bottom of water.

The term "corner" in the context of this application refers to any construction that is suitable to be connected with the framework beams and with the transverse beams. The construction of the corners can for example be a box-like or latticelike construction. Box-like constructions are to be preferred because they can be filled with water and gas in order to float, immerse, or lift the framework. When the framework is positioned at the bottom of the body of water in the immersed state, the buoyancy capacity of the framework can be increased by pumping water from the compartments. The thus created vacuum will create a force in the upward direction. The water is preferably replaced by a gas. Hereto, the compartments are sealably connected with a reservoir in which a gas is stored under pressure. Such a reservoir is preferably connected to the framework. When the gas in the reservoir is used up, it can be replenished via a conduit that is connected to a pressure container on the floating vessel. These reservoirs and containers can comprise compartments with a pressurised gas. By using the compartments individually, it is possible to deliver a more constant pressure to the multiple systems. These pressure containers can also be replaced by new pressurised containers. The used reservoirs and containers can be refilled using a compressor that is present on the floating vessel, or new reservoirs and containers can be brought over from the mainland. The gas preferably is air but can also be nitrogen or carbon dioxide.

The corners of the rectangular framework preferably comprise the anchoring means. These means preferably consist of a screw anchor or of a suction anchor. The means to anchor the rectangular framework into the bottom soil preferably comprise an anchor that is situated on the bottom side of a shaft. This shaft is vertically movably positioned in an opening in the corner. Part of the shaft extends above the corner and another part extends below the corner. The upper part of the part of the shaft that extends above the corner is connected to the corner by means of one or more linear actuators. These actuators can be electromechanical actuators and preferably hydraulic cylinders. The shaft can also serve as anchoring means without a screwing anchor or a suction anchor. The shaft is pressed into the bottom soil under the influence of a suitable compressive force of the actuator, and is pulled out of the bottom soil under the influence of a suitable traction force. The suction anchor in itself is known and comprises a tubular lower part with an open extremity. Instead of a tubular lower part, basically also other forms can be used that have the same effect. Tubular lower parts offer the advantage that the pressure difference between the inside and the outside of the suction anchor is distributed optimally. By creating an under-pressure inside the tubular opening, for example by pumping away the water that is present, the tube draws itself into other bottom soil. By retracting the said actuators, the suction anchor can thus be driven into the bottom. A suction anchor is connected to the shaft, preferably by means of a ball joint. Especially in the case of a slanting bottom of the body of water this holds an advantage. In case of harder bottom soils, it can be

advantageous to equip the bottom side of the suction anchor with a rotating disc that comprises cutting teeth. This disc can be driven by a motor.

Screw anchors are known as such and usually consist of an axis around which a continuous cutting blade with a certain pitch is wound in the form of a helix. The cutting blade can comprise cutting teeth when relatively hard bottom soils need to be driven into. The screw anchor is preferably driven by a motor with a large torque at low rotational speeds. When the anchor is driven into the bottom soil the motor is rotated at a speed and driving torque that are suited for the soil type, and at the same time is screwed into the soil by applying a suitable compressive force by reducing the said actuators. When cutting into sandy soils in relatively large water depths, the reaction forces on the cutting blade can become too big because of the created under-pressure in the soil at the level of the cutting blades and because of the limited inflow of water in the direction of the cutting blades. In such a situation it can be advantageous to make use of the screw anchor comprising a hollow shaft around which a helical cutting blade is positioned, and whereby in the wall at the level of the helical cutting blade discharge openings are foreseen that are in connection with a supply conduit in the hollow shaft for a gas or a liquid. Preferably use is made of a liquid. This liquid is preferably water that is being drawn in at a higher level and that is pumped through the discharge openings by means of a pump, for example a centrifugal pump. By supplying a gas or a liquid, the creation of a local vacuum is inhibited, so that the possible seizing up of the anchor can be avoided.

The corners of the rectangular framework preferably comprise supporting means. Examples of suitable supporting means are a skid, a wheel, or a caterpillar track. The supporting means are preferably resiliently connected with the corners. The supporting means are preferably connected with the corners by means of vertically adjustable linear actuators. The framework can be positioned in the desired position with reference to the bottom soil, for example vertically, with the help of these actuators.

The rectangular framework preferably comprises one or more jets, propellers, or thrusters that enable a vertical and/or horizontal movement of the framework in a floating, immersed, or lifting situation. These means can also be used to move the framework over the bottom of the water body, when the framework rests on the supporting means or floats between the bottom and the water surface.

The tiltable part of the framework comprises connecting means to fix the windmill or at least the foundation of a windmill. These connecting means can be clamps that can be actuated for opening or closing by means of hydraulic or electric engines or by means of linear actuators, more specifically double sided hydraulic cylinders. At the other end, these connecting means can be, for example by means of axes, connected to the fixed part of the framework, in such a way that a construction is obtained that enables the tilting of the windmill foundation or of the windmill. The tiltable part preferably comprises a lattice structure. The connecting means are in this case placed on the tiltable lattice structure. This lattice structure is then in turn connected by means of one or more actuators to the fixed part of the framework. The tiltable lattice structure preferably comprises linear actuators that have an effect in the longitudinal direction of the lattice structure. This is

important in case the windmill rotates via a rotation axis other than the lattice structure. By extending or retracting the actuators, the distance between the connecting means on the lattice structure can be adjusted, in such a way that the combination of the windmill and the lattice structure can tilt in an upward direction. This way, the lattice structure can support a windmill that turns around a rotation axis that is parallel to but not equal to the rotation axis of the tiltable part.

The linear actuators or, as referred to in this application, the actuators can be electromechanical actuators and preferably hydraulic cylinders.

The framework here described can also advantageously be used to remove already installed windmills in a controlled manner from the bottom of a body of water. Therefore, the invention relates to a method for the removal of a

foundation that is connected to the bottom of a body of water by means of anchoring means, the method comprising the steps of:

(k) lowering or immersing the framework,

(I) positioning and anchoring the framework to the bottom of the body of water, adjacent the foundation,

(m) connecting the framework to the foundation,

(n) disconnecting the anchoring means from the foundation,

(o) tilting the foundation from a substantially vertical position to a

substantially horizontal position on the framework, and

(p) decoupling the anchoring from the framework, and consecutively bringing the framework and the foundation to the water surface. The corresponding terms used in this method have the same meaning as those used in the rest of the description. The execution of steps (k), (I), (m), (n), (o), and (p) can be identical, however in some cases in reverse order, to the one described for steps (a)-(d). The disconnection of the anchoring means from the foundation in step (n) can for example be carried out using blowtorches that are connected to the framework and/or to a working vehicle that moves over the bottom. The foundation is preferably disconnected from the anchoring means in a position just below the bottom surface. This way a bottom can be obtained that is substantially identical to the bottom as it was present before the windmill was installed. In this method, the foundation can still be connected to the mast, the generator, and the blades. Possibly one or more of these parts can already be removed before the method is carried out. After the framework and the

foundation of the windmill has arrived in step (p) on the water surface, the foundation or the windmill can be removed from the framework. The framework can then advantageously be used to remove a further foundation or a windmill according to this method. The thus obtained foundation or windmill can be transported to the mainland, as a whole or in parts. Step (o) can possibly also be executed, whereby the windmill is tilted into a position in which the generator of the windmill stays above the water surface. In step (p) the windmill will be tilted more into a horizontal position while the framework is being brought up to the water surface.

The invention also relates to a floating vessel that is suitable for connecting to the immersible framework according to this invention as described here before and as can be seen from the figures. The floating vessel comprises a recess in its hull in which the framework can be positioned. From this recess, the framework can be immersed in a vertical direction. The recess may be a closed opening from which the framework can only detach from the vessel by immersing the

framework-windmill combination towards the bottom of water or have an opening such that the framework-windmill combination can alternatively detach from the vessel by moving the vessel away while the framework is immersed and part of the windmill is above the water level.

The floating vessel provided with the immersible framework may be provided with a windmill as stored on a floating dock or a quay. The floating dock or quay preferably comprises a storage space for windmills that are positioned in a substantially horizontal position. This storage space can be the deck of the floating dock or a recess in the hull of the floating dock or in the harbour quay. The recess in the hull or in the harbour quay forms a basin or a dock in which windmills can advantageously be stored floatingly. The nacelle comprising the generator, bearings and electronics is preferably water-resistant incorporated in a floater when stored in this manner. The advantage of a floating storage space is that the windmills can be moved to the framework floatingly to carry out step (a) of the method according to the invention. Proceeding accordingly the use of heavy cranes can be avoided for transporting windmills or foundations of windmills from the storage space to the framework. Between a basin for receiving the floating vessel and framework and the recess in the hull or harbour quay, a sealable door is preferably present, comparable to a sluice gate.

The floating dock or harbour quay can also comprise a space in which a windmill can be assembled in a substantially horizontal position by combining at least the foundation, the mast, the generator, and/or the blades with another component from this list, whereby means are present to transport the assembled windmill to the storage space. The space to assemble the windmill preferably comprises one or more dry docks. Thereby, it is possible to obtain an assembled and floating windmill that can be floatingly transported to the stored facility and from there also floatingly to the framework. This is advantageous because it eliminates the necessity of using heavy cranes. The above-mentioned floating dock can comprise a single hull or can consist of multiple floating vessels, for example pontoons.

The invention also relates to an assembly of a framework as described above and in the figures, with a floating vessel as described above and in the figures, whereby the framework is connected to the floating vessel by means of cables with an adjustable length.

The assembly preferably comprises a controlling unit that is suitable for the transport of the framework from the floating vessel to the bottom of the body of water, (i) to position the framework at the bottom of the water and to anchor it, (ii) to move the windmill connected to the framework or at least the foundation of a windmill, from a horizontal position or a position that forms an angle with the bottom of the body of water to a vertical position, (iii) to anchor the foundation of the windmill into the bottom of the body of water, and (iv) to move the framework from the body of water to the floating vessel. The floating vessel is therefore advantageously equipped with a positioning system, in such a way that the framework can be manoeuvred into the desired position to install the windmill. The invention also relates to a windmill suitable for use in the method according to the invention, comprising a foundation, a mast, a generator, and blades, whereby the mast and/or foundation comprises more than one compartment that can be filled with a gas in order to make the windmill float, and with water in order to be able to immerse the windmill. The generator is preferably enclosed by a watertight floating housing that can be removed.

The invention also relates to the connection of one or more windmills that are installed according to the method of the present invention with the mainland in order to transport the electrical energy generated by the windmill or windmills. The invention also relates to the electrical energy generated by the windmills. The applicant is convinced that by using the present invention the installation costs of a windmill, for example on a seabed, can be drastically reduced. It is also the applicant's conviction that significant time savings in the logistical chain of producing, storage, transport, and installation of windmills can be achieved by applying the invention. Thereby also the cost of the electricity generated by means of the windmill will be significantly lower. This is the reason why the directly obtained product of the installed windmill, namely the generated electricity, is also part of the present invention. And that is also why the invention is broadened to the electricity product of the windmill, as users of the method according to the invention could claim that they do not infringe the patent because they use the method far from the coast of the mainland where the patent is valid. The invention shall hereafter be illustrated by means of the following non-limiting figures.

Figure 1 a is a side view of a windmill (2) of the monopile type, consisting of the main components such as a mast (3), a generator (7) that is attached to the other side and that is rotatable in the longitudinal direction around the mast (3), as well as blades (6). To prevent the windmill (2) rising in the vertical position during the installation in step (e), compartments (4a) are foreseen at the bottom side of the mast, compartments that can be filled with surrounding water. Fixing the vertically positioned windmill (2) into the bottom soil is realised by driving the windmill (2) into the soil or by creating a vacuum using suction anchors that are attached to the bottom side of the mast (3).

Figure 1 b is a side view of a windmill (1 ) of the tripod type, whereby, further to the main components that were already shown in figure 1 a, at the bottom side of the mast (3) a tripod foundation (5e) is foreseen that offers a good stability and rigidity. The foundation (5e) is composed of a triangle (5d). The triangular structure (5d) is connected to the mast (3) in its three corners by means of three diagonal bars (5f) and three bars (5b). The corners of the triangle each also comprise a vertical hollow shaft (5c). Also in the windmill of the tripod type (1 ) water compartments (4a) are foreseen. Fixing the vertically positioned tripod (1 ) on the seabed in step (e) can be carried out by driving piles, for example using hydro-hammers, that are positioned through the hollow guiding shafts (5c), as can be seen in further detail in figure 13. Step (e) can also be carried out by using suction anchors that can be fixed to the bottom side of the guiding shafts (5c). By creating a vacuum, the suction anchor can immobilise the foundation on the seabed.

Figure 1 c shows a perspective view of the windmill according to figure 1 b. Here, the positions and the connections between the bars (5f, 5b, 5d) and the mast (3) and the shaft constructions (5f) are spatially represented.

Figure 2 shows a possible embodiment of the immersible framework according to the invention. Using this framework (3a), the method according to the invention can be carried out, for example with windmill types as represented in figure 1 . The framework (3a) comprises a fixed part and a tiltable part. The fixed part is a rectangular framework (3a) that comprises framework beams (9, 1 1 ) and transverse beams (10, 12) that are mutually connected in the corners (6) by means of a resilient ball-joint connection. The four corners (13, 14, 15, 16) comprise a skid (7a) as supporting means, an anchoring construction (8), and thrusters (17a, 17b). These corners shall be described in further detail in figure 20. Because of the resilient ball-joint connections between the framework beams (9, 1 1 ), the transverse beams (10, 12) and the corners (13, 14, 15, 16) and the resilient connection with the skids (7a) the framework (3a) is in possession of six limited kinematic degrees of freedom. In the framework beams (9, 1 1 ), transverse beams (10, 12), and corners (13, 14, 15, 16) compartments are foreseen that can be filled with and drained from water in order to immerse or float the framework (3a). The horizontal thrusters (17b), with vertical driving power, can help to stabilise the framework (3a) further during the floating or immersing operation. Thrusters (17a) that are rotatable around vertical axes (difficult to see in the figure) can for example be used for moving the framework (3a) while floating as well as on the bed in the horizontal plane.

As can be seen in figure 2, the framework (3a) is reinforced by adding transverse and diagonal tubes (20) that are connected to the framework beams (9, 1 1 ). With the transverse tubes (20) are connected supporting constructions (34) that comprise clamping mechanisms (35). By means of these clamping mechanisms the mast (3) of the windmill can be connected to the fixed part (3b) of the framework (3a). From step (b) or (d) the clamping mechanisms will be opened.

The corners (13, 16) are connected to a stationary axis (37) which, for reasons of strength and rigidity, are connected to the transverse beam (12) (diagonal tube 37b is not visible in this figure) by means of tubes (37a, 37b). Around the bearings (38) of the stationary axis (37) a clamping and tilting mechanism (5a) rotates that is suitable for connection with two suction anchors of a foundation of a windmill of the tripod type, as can be seen in detail in the figures 6a-c and 7. The clamping and tilting mechanism (5a) comprises clamping mechanisms (40, 41 ) for suction anchors, as can be seen in further detail in figure 6. The clamping mechanisms (40, 41 ) are mutually connected by means of vertical plates (39).

The framework (3a) comprises a tiltable lattice construction (4) to support the mast (3) of the windmill in step (d) and step (e). The lattice construction (4) has the shape of an isosceles triangle with a truncated top. The lattice construction (4) is made up of two tapered/bevelled tubes (28a) and transverse and diagonal tubes (28b) that help to increase the rigidity. The lattice construction (4) hinges by means of bearings (22) around the stationary axis (21 ) that is transversally connected to the framework beams (9, 1 1 ). The hydraulic cylinder (23) is rotatably foreseen around the stationary rotation axis (26) by means of the bearing (25), whereby the axis is connected to the transverse beam (12) by means of rings (27). The functions of the hydraulic cylinder (23) are consecutively the controlling or adjusting the rotating movement during the erection in step (d) of the method and the lowering of the lattice construction (4).

Because the axes (21 , 37) of the lattice construction (4) and the clamping and tilting mechanism (5a) of the windmill do not coincide, the lattice construction (4) comprises means to extend in the longitudinal direction of the windmill that is to be installed. In the embodiment of figure 2 a clamping mechanism (33) is therefore foreseen for connecting a mast of the windmill to the top and of the lattice construction (4). The clamping mechanism (33) is connected by means of a hinge (32) and the surrounding ring (32b) to an axis (31 a) in the transverse direction. The ends of the axis are in turn connected by means of bearings (30) and two hydraulic cylinders (29) to the rest of the lattice construction (4). In figure 10 the functioning of the cylinder (29) during step (d) of the method can be seen.

The axis (31 a) of the lattice construction (4) is supported by a supporting construction (36a) that is connected to the transverse tube (36). Reference is also made to figure 9. Figures 13d and 14b show representations of possible functioning mechanisms for the clamping mechanisms (33, 35, 40, 41 ).

Figure 3 shows a plan view of a floating vessel (61 ) that comprises a recess (61 a) in which a framework (3a) that can be seen in figure 2 is positioned, on which a windmill (1 ) of the tripod type, comprising suction anchors (5), is positioned. The figure shows the lattice construction (4) as well as the clamping and tilting mechanism (5a). Also represented are the corners (13, 14, 15, 16) comprising the skid (7a) and the anchoring construction (8) of which only the upper parts are visible. The reference numbers of the components correspond to the numbers used in figure 2.

The floating vessel (61 ) is connected to the framework (3a) by means of winch cables for which winches (51 ) are used. From the winches (51 ) winch cables (52) run to the framework beams (9, 1 1 ), as can be seen in further detail in figures 8 and 19. Using the winches (51 ) the framework (3a) alone or in combination with the windmill (1 ) can be immersed at the bottom, and the framework (3a) can be raised back to the floating vessel (61 ). Figure 3 also shows a bridge (54) that connects two halves of the floating vessel (61 ). On the bridge (54) a winch installation (60c) is positioned. With the help of this winch installation (60c) a floating windmill (1 , 2) can be transported from a (not represented) storage space for windmills (1 , 2) to the framework (3a). The winch cable runs via guiding rollers (60d). If necessary, additional flotation bodies can be attached around the mast (3) of the windmill (1 ) or around the lattice construction (4) (see figure 1 1 ), before step (a) of the method is carried out. Before the floating windmill (1 ) is prepared to carry out step (a) of the method, it can be useful to immerse the framework (3a) a couple of metres by activating the winches (51 ) so that they let go of the cables in combination with partially filling the compartments that are present in the framework beams (9, 1 1 ), in the transverse beams (10, 12) and/or the corners (13, 14, 15, 16) with water.

Figure 4 is identical to figure 3 under the assumption that a windmill (2) of the mono-pile type is connected to the framework (3a), whereby a clamping and tilting mechanism (5b) is used that is suitable for this specific type of windmill. The clamping mechanism is shown in further detail in figure 13d. Around the mast (3) of the windmill (2) a flotation body (50) is positioned to create (additional) buoyancy in order to thus assist the rotating movement of the windmill (2) from a horizontal position underwater to a vertical position. Such a flotation body (50) can also be incorporated into the lattice construction (4). Figure 4a shows the framework (3a) including corner constructions (6), which is clamped in a u-shaped transport vessel (61 ). The typical U-shaped vessel (61 ) for example allows the vessel (61 ), after or while erecting the windmill or when submersing the framework (3a) to disassociate from the framework (3a) and windmill combination via its open end. The functions of the winches (51 ) are clamping the framework (3a) into the u-shaped transport vessel (61 ) and guiding the framework (3a) downwards or upwards. In this case the pump installations (51 a) and the compressor installations (51 b) are positioned on the u-shaped transport vessel (61 ). The vessel (61 ) can consist of three separate pontoons as seen in this Figure 4a.

Figure 5 shows a plan view of a floating vessel (53a, 53c, 53d) comprising the floating vessel (61 ) that is represented in figure 4, the framework (3a), and a windmill (2) that is fixed thereto. The floating vessel (53a, 53c, 53d) in

combination with the floating vessel (61 ) can comprise propulsion systems (not visible in this figure). The floating vessel (53a, 53c, 53d) can have a modular design and can be assembled into a unit by coupling separate parts (53a, 53c) and (53c, 53d). At the front of the floating vessel (53a, 53c, 53d) a coupling of the two parts (53a) takes place by means of two bridge constructions (54) through which a rigid construction is obtained. At the rear of the floating vessel (53a, 53c, 53d) a coupling of the two parts (53d) takes place by means of a bridge construction (55a) with which, in combination with the bottom plate construction (58a), a rigid construction is obtained. The recess which comprises water and a bottom plate construction (58a) forms a storage space (57a) for floating windmills (2) of the mono-pile type (2). In view of an optimal use of the available space in this storage space (57a) the plane in which the blades (6) turn is positioned vertically. The recess in the floating vessel (61 ) and the storage space (57a) are separated by a partitioning wall (59a) that can be opened and closed. With such an open connection, a floating windmill (2) can be transported from the storage space (57a) to the framework (3a), as present in the floating vessel (61 ).

Figure 5 also shows a series of dry docks (58c, 58d) that are positioned side-by- side and in which the windmills (2) are assembled by combining at least the foundation, the mast, the generator, and/or the blades with another component. The assembling takes place in steps and in successive docks or dry docks, after which the assembled windmill (2) eventually arrives in the central dock (58e). From this dock (58e), the assembled windmills (2) can be transported to the storage space by opening the sluice gate (59b).

Figure 5 shows how the mast and the foundation are assembled in a dry space (58c) with the generator. Blades are attached to the thus intermediate product in an adjacent dry dock (58d). The dry dock (58d) can then, after the partitioning wall (67a) has been closed, be filled with water by opening the partitioning wall (67b) and possibly, for adding water from the exterior, by opening the partitioning wall (59b). The floating windmill (2) can now be transported to the central dock (58e). The partitioning walls (67b) are opened during this transport, for example by tilting these walls around the rotation axis of hinge (56b) by means of hydraulic cylinders (56a) as can be seen in the figure.

Because of the partitioning wall (59a) and the bottom plate construction (58a) the stored windmills are protected against external conditions in a storage space (57a) that is separated from the surrounding water, and as such the drag during the navigation can be reduced. The bottom plate construction (58a) can possibly be omitted, whereby an open connection with water under the floating vessel is created. The walls (59a) can in their vertical position be rolled away in the transverse direction of the ship, for example in guiding tracks at the sides of the pontoons (53a) or can, as described above, be opened with hinges on the bottom plate and by means of hydraulic cylinders. The coupling between the floating vessel (53a, 53c, 53d) that comprises the storage space (57a) and the floating dock (53b, 53e) takes place by coupling the pontoon parts (53d, 53e) and the pontoon parts (53c, 53b). The "handling" for the transport of the floating windmills (2) to the storage space (57a) and possibly back takes place by means of the winch (60a) in combination with guiding rollers (60b). The transport of the floating windmill (2) from the storage space (57a) to the flooding framework (3a) in the floating vessel (61 ) and possibly back takes place by using winches (60c) on the floating vessel (61 ).

The floating dock part (53b, 53e) comprises a recess (57b) that at the bottom side is closed off by a bottom plate construction (58b). This space comprises multiple dry docks (58c, 58d) in which the windmills are assembled. At the front and rear sides of the dry dock (53b, 53e) a coupling of the two parts (53e) takes place by means of two bridge constructions (55b) with which, in combination with the bottom plate construction (58b), a rigid construction is obtained.

The front and the rear of the floating dock (53b, 53e) are closed off by folding or sliding doors (59b). The exterior door (59b) of the floating vessel can be used to bring over windmills that have been assembled at a different location. The consecutive compartments (58c, 58d) and (58d, 58e) can be separated from one another with folding or sliding doors (67a) and (67b). The partitioning wall (59b) (sluice/sliding door) can be opened as a folding door by means of two hydraulic cylinders (56a) with hinges (56b) at the bottom side of the door or by the opening in a transversal direction of two rolling doors (not represented in the figure). After assembling the windmills (1 , 2) in compartment (58c) the windmill (1 , 2) can be moved to the last compartments (58e) of the floating dock via the intermediate sluice (58d). All this takes place by opening and closing the respective doors (67a, 67b). For all the bridge constructions it is to be understood that the free width as well as the height has to be sufficient for the passage of a floating windmill (1 , 2). Figure 6a, b, c shows the clamping and tilting mechanism (5a) of the framework (3a) of figure 2 from different viewpoints. In figures 6a and 6b also the foundation of a windmill (1 ) of the tripod type can be seen. This foundation comprises suction anchors (5). For the installation of the foundation on the framework (3a) the clamping and tilting mechanism (5a) can be rotated over an angle Θ of 90° around the stationary rotation axis (37) by a ring engine (38a) positioned on axis (37). In figure 6a the two clamps (40) suited for clamping the suction anchors (5) are in an open position. The clamps (41 ) for clamping the tubes (5c) are still closed in figure 6a but have to be open before the windmill (1 ) can be positioned on the framework (3a). After the windmill (1 ) has been correctly positioned on the framework (3a) and the mast (3) of the windmill has been connected to the framework (3a) by means of multiple sliding clamps (35), the clamping and tilting mechanism (5a) is rotated over an angle Θ of -90°, whereby the suction anchors (5) and the tubes (5c) are clamped in the successive closed clamps (40) and (41 ), as can be seen in figure 6b. After the clamping and tilting mechanism (5a) with the clamped windmill (1 ) has been rotated over an angle Θ of 90° around the stationary rotation axis (37), as in step (d) of the method according to the invention, the clamps (40, 41 ) can again be opened as is also indicated for clamps (40) in figure 6a. Figure 6c shows the connection of the clamping and tilting mechanism (5a) to the transverse beam (12) where the stationary rotation axis (37) is fixed to the transverse beam (12) by straight (37a) and diagonal (37b) cylindrical bars. Figure 7 shows a plan view of the framework (3a) of figure 2 with a lattice construction (4) and a windmill (1 ) of the transport type installed thereon, as can be seen in figure 6b. The reference numbers have the same meaning as in the previous figures. This combination can in step (b) of the method be immersed and positioned at the bottom of a body of water. Once positioned there the framework (3a) rests on the resilient skid (7a). The displacement of the corners (13, 14, 15, 16) is represented as Z13, Z14, Z15, and Z16. The framework (3a) can be placed in a horizontal plane by means of a vertical movement of the hydraulic cylinders (121 ) that are represented in further detail in figure 20. This way also the rotation angle Φ around the longitudinal axis of the framework (3a) can be minimised to 0. After placing the framework (3a) on the bottom of the body of water the framework (3a) is immobilised and anchored to the seabed by means of screw anchors (8) (65; references have also been made to figures 10 and 1 1 ). Hereafter, step (d) of the method can be carried out as described in figures 9-1 1 .

Figure 8 shows a perspective view from above of the way the framework (3a) with the lattice construction (4) and the windmill (1 ) placed on top thereof is immersed from the floating vessel (61 ), as in step (b) of the method. The immersion of the framework (3a) is carried out in a controlled manner by off winding the winches (51 ), whereby the cables (52) are connected with the framework (3a). The thus created upwardly directed force of the air filled mast (3) of the windmill is compensated by the weight forces of the framework (3a) and by adding water to the compartments of the framework (3a). Figure 9 shows a representation of the combination of the framework (3a), the lattice construction (4), and the windmill (1 ) of figure 7 after step (d) has been carried out. The windmill (1 ) has then been moved from a horizontal position as can be seen in figure 7 to a vertical position by the carrying out of rotation around a substantially horizontal rotation axis (37). A rotation around the rotation axis (37) over an angle Θ is controlled and facilitated by extending or retracting the hydraulic cylinder (23) and the hydraulic cylinders (29), fixed to the lattice construction (4), over respective distances L23 and L29.

Figure 10 shows a representation of the movement of the windmill (1 ) from a horizontal position to a vertical position in four steps by means of a rotation around a substantially horizontal rotation axis (37). The combination of the framework (3a) and the windmill (1 ) is the same as the one that can be seen in figure 9. After opening the clamping mechanisms (35) in position P1 the horizontally positioned windmill (1 ) shall move in an upward direction under influence of an upwardly directed couple around the rotation axis (37). The upwardly directed couple is generated by the upward force of the air filled compartments in the mast (3) and the flotation body (50) that is connected to the mast. By using the flotation body (50) a sufficient resulting erecting couple is generated for all phases. The same lifting procedure can be followed from position P2 up until P4 with the starting position P2 of the windmill generator (5) above sea level, preventing the generator from being wet. The rotation around the rotation axis (37) is carried out in a controlled manner by using the hydraulic cylinder (23) that on the one side is connected to the lattice construction (4) and on the other side to the framework (3a). If no use is made of a flotation body (50), the additional uplifting couple will have to be created by extending the hydraulic cylinders (23) and/or the hydraulic cylinders (29) that are positioned on the lattice. Position P2 indicates a position in which the bending moment shows a relatively high value due to the weight forces of the generator (7) and of the blades (6) as well as a part of the mast (3) and lattice construction (4) above the water surface (66). To prevent the total of the bending moment being taken up by the mast (3) of the windmill (1 ), a lattice construction (4) is foreseen at the upper side of the windmill (1 ) with a rotation axis (21 ), coupled to the framework (3a), at a distance as far as possible in a horizontal direction from the rotation axis (37) of the windmill (1 ). In order to be able to withstand a bending moment, the cylinder rods of the hydraulic cylinder (29) are equipped with (not visible in the figure) water permeable hollow tubes, placed around the cylinder mantle of the hydraulic cylinder (29) . Position P3 indicates that the resulting weight forces of the generator (7) and blades (6) and of the mast (3) and lattice construction (4), reduced with the upward forces of the underwater lattice construction (4) and mast (3) will, for the larger part, be taken up by the substantially vertical lattice construction (4). In position P4 the tripod (1 ) has reached the eventual desired vertical position. It is possible to carry out a correction of the angle around the rotation axis (37) by extending or retracting the hydraulic cylinder (23) and/or the hydraulic cylinders (29), fixed to the lattice construction (4). The flotation body (50) can now be removed from the mast (3), and the compartments (4a) can be filled with water. The suction anchors (5) can, under the influence of a suction effect, be sucked into and immobilised on the seabed after the correct positioning of the windmill (1 ). By means of the guiding mechanism of the clamps (40) around the suction anchors (5) at the bottom side of the windmill, and of the guiding

mechanism (33) of the clamp (33) at the top side of the windmill (1 ) a slanting positioning of the windmill (1 ) can be prevented, for example due to an

asymmetric suction effect of the suction anchors. After fixing the tripod foundation (5e) into the bottom of the body of water the clamps (40) around the suction anchors (5), the clamps (not represented in the figure) around the tubes (41 ), and the clamp (33) of the lattice construction (4) around the mast (3) can be opened successively. The lattice construction (4) can be lowered in a controlled manner by the hydraulic cylinder (23) and fixed to the fixed part of the framework with clamps (31 - see figure 9). The lattice construction (4) is preferably made up of tubes (28a, 28b - see figure 2) that are filled with air. This gives rise to an upward force that will advantageously decelerate the lowering of the lattice construction. As can be seen from figure 10, the lattice construction (4) rotates around a different axis (21 ) then the axis (37) around which the windmill (1 ) rotates during the erection of the windmill (1 ). The axes (21 ) and (37) are nevertheless

positioned parallel without being positioned coaxially. By extending the hydraulic cylinder (29) during the erection of the windmill it is possible to direct this combination of a lattice construction and windmill.

Figure 10a shows a perspective view of the framework (3a) including the lattice construction (4) provided with a stiffness construction (4a). The stiffness

construction (4a) provides additional support to the mast of the windmill such to minimise local loads on the mast of the windmill. The stiffness construction (4a) comprises of two beams on top (4b), which are connected to bearings (31 b) around axis (31 a) and are connected to a windmill supporting gutter (4c), which at the bottom is connected to beams (4d), which for stiffness reasons are connected to outside beams (4e), which on top are connected with the gutter (4c) and at the bottom are connected with beams (41 f), which are connected with bearings (4g) rotating around axis (37). This construction allows the windmill to be moved from a horizontal or angled position to a vertical position while the stiffness construction (4a) provides a support along part of the length of the mast of the windmill as exemplified in Figure 10b.

Figure 10b shows a representation of the movement of the windmill (1 ) from a horizontal position (position P1 ) to a vertical position (position P4) by means of a rotation around the rotation axis (37), which is connected with the framework (3a). As can be seen the mast is continuously supported by the gutter (4c) in all positions P1 -P3. During erection the lattice construction (4) extends by extending hydraulic cylinders (29). In this drawing a stiff flexible triangle consisting of the lattice construction (4), including the hydraulic cylinders (29), the stiffness construction (4a) and, via the rotating axes (37, 21 ), the framework (3a) is clearly shown for all positions. This stiff flexible triangle is able to withstand all loads working on the windmill (1 ) during the rotation movement.

Figure 1 1 shows the combination of forces during the erection of the windmill. Figure 1 1 shows a side view of the stationary framework (3a) and the rotating windmill (1 ) coupled to the lattice construction (4), in a position that is similar to position P2 of figure 10. In this position the largest bending moment occurs in the mast (3) of the windmill (1 ) in combination with the lattice construction (4), and it is difficult to carry out the desired rotation around the rotation axis (37). The mast construction (3) of the windmill (1 ) - line A-B-C - and the supporting lattice construction (4) - line D, E, F - are schematically shown in the symmetry plane by means of bold black lines. The mast construction (3) rotates in this case around the rotation axis (37) connected to the framework (3a) - represented as roller bearing A - while the lattice construction (4) rotates around the rotation axis (21 ) connected to the framework (3a) - represented as roller bearing F. The lattice construction (4) is supported by the hydraulic cylinder (23), represented schematically by line EG. The point E is a rotation point that is connected to the lattice construction (4), while point G represents the rotation axis that is connected to the framework (3a) - represented as roller bearing. The

construction A-B-C-D-E-F forms a rigid construction and has to be sufficiently strong to resist the load, for example induced by the bending moment around the transverse axis of the vessel. The bending moment or the rotating couple is created by the combination of upwardly directed forces O of the mast

construction (3) and the lattice construction (4) underwater, to which possibly a flotation body (50) on the mast construction (3) and/or lattice construction (4) has been added, as well as the resulting weight force M1 due to the weight forces above the water surfers of successively the generator (7), the blades, the mast construction (3), and a lattice construction (4), as well as the resulting force M2 due to the mass forces of the part of the mast (3) and lattice construction (4), as well as the foundation with the suction anchors under water. In this figure the flotation body (50) is connected to the lattice construction (4). This is preferred over a situation wherein the flotation body is connected to the mast because it avoids a large bending moment in the mast due to the large buoyancy force of the flotation member and because the flotation body does not need to be removed after the windmill (1 ) has been positioned. During the lowering of the lattice construction (4) the flotation body (50) shall create a counter acting moment that has to be compensated by the weight of the lattice construction underwater and for example by removing part of the air from the flotation body, or by having the hydraulic cylinder (23) exert more force. By anchoring the framework (3a) to the bottom of the body of water by means of screw anchors, and under influence of the weight force of the framework (3a) underwater, and taking into account the effect of water in the compartments of the framework beams (9 to 1 1 ), the resulting bearing forces at the level of the screw anchors can be transferred to the bottom of the body of water (65).

Figure 12 shows a perspective view of the stationary framework (3a) comprising the corners (6), the skid (7a), and the vertically rotated foundation of a windmill of the tripod type (1 ). The foundation comprises suction anchors (5) and part of the mast (3), so that these extend to immediately above the water services in the vertical position. However, the foundation does not comprise a generator and blades. In this situation it is not necessary to make use of a lattice construction (4) since the relatively large weight forces of the generator and the claims are absent. To carry out the erection of the foundation and the mast (3) in a controlled manner, use is made of a hydraulic cylinder (80) as the tiltable part. The hydraulic cylinder (80) is rotatable at the bottom side around the transverse axis of the vessel (26) thanks to a bearing construction (25) which is positioned on the transverse beam (12) of the framework (3a), and is rotatable at the top side around the transverse axis of the vessel thanks to the hinge (81 ), and is

connected to the mast (3) via a clamping mechanism (82). After the correct positioning of the foundation and the mast (3), and the anchoring of the suction anchors (5) to the bottom of the body of water (65), the clamp (82) around the mast (3) is opened and the hydraulic cylinder (80) will be returned to its original position by the hydraulic cylinder (83). The hydraulic cylinder (83) is connected at its top side by means of a hinge (84) and ring (85) to the hydraulic cylinder (80). At the bottom side the hydraulic cylinder (83) is rotatably connected by means of the hinge (86) to a transverse beam (20) of the framework (3a). The method as illustrated in figure 12 can advantageously be applied in relatively large water depths. The generator, blades, and possibly a further part of the mast can simply be positioned on this foundation after step (e) has been carried out. Figure 13a shows a front side of a windmill (1 ) of the tripod type, whereby the anchoring to the bottom takes place by means of piles (77) that are driven into the bottom. The three piles (77) pass through the three hollow shafts (5c in figures 13a-b) of the windmill. The piles are clamped at the bottom side in the clamping/guiding mechanisms (70c). At the top side the piles (77) are surrounded by cylindrical shafts (73) that are connected to bearings (71 ). The shafts (73) are connected to one another via the connected bearings (71 ) by means of constructions (75, 76). Above the shafts (73, 73a) a hydro-hammer (74) is positioned on every pile (77). By using the hydro-hammers (74) the piles (77) can be driven into the bottom. The piles (77) are slidingly guided through the clamping/guiding mechanisms (70c). Thereby also the shafts (73) and the constructions (75, 76) connected thereto are lowered in a vertical direction. Once the piles (77) have been sufficiently driven into the bottom, the construction (75, 76) is detached from the piles (77). For this, the construction can fold open as can be seen in figure 13b. Thanks to the possibility of folding open these constructions (75, 76) and hence also the framework (3a) can detach themselves from the anchored windmill (1 ).

Figure 13b shows how two hydro-hammers (74) are connected to the

construction (75), while one hydro-hammer is connected to the construction (76). The constructions (75) and (76) are mutually coupled by an eye construction (78) that can be automatically closed (also see figure 13g). To prevent a slanting position of the constructions (75, 76) with reference to the horizontal plane, the three piles (77) have to be loaded simultaneously or in a synchronised way by the hydro-hammers (74). The direction of the resulting driving force of the three hydro-hammers (74) then passes through the vertical central line of the tripod mast (3). Variations in the characteristics of the soil per pile (77) and the corresponding variations in the sole reaction forces on the piles (77) are met by the rigidity of the triangularly assembled lattice constructions (75, 76). The lattice constructions (75, 76) are connected at the front side with the eye construction (78) and at the rear side connected with a rod (75a - see figure 13e) via bearings (71 ) and rings (72b). In order to accommodate large variations in the soil characteristics during the driving of the piles, which could create excessive loads at the level of the eye construction of the shaft (73a) and bearings (71 ), ball joints (not represented in the figure) can be attached to the bearings (71 ) and the vertical shaft (73a). The piles (77) are guided at the bottom side by three hollow shafts (5c) of the tripod formation, positioned in the corners. The shafts (5c) are clamped by means of clamping mechanisms (70) - (for further details, see also figure 13c and 13d), part of the tilting and clamping mechanism (5a). After the pile driving, the constructions (75, 76), hydro-hammers (74), and shafts (73, 73a) are coupled to the tilting and clamping mechanism (5a) by means of a releasable clamping connection (72a, 72c - see figure 13e).

Figure 13e shows in further detail the releasable clamping coupling consisting of a ring (72b) connected to the shaft (73) and a conical funnel (72c) that is to be clicked into a ring (72a) that is fixed with the tilting and clamping mechanism (5a), in which the conical funnel (72c) fits. As a clicking mechanism, use can for example be made of a resilient and automatically magnet activated ball/pen mechanism. Once the conical funnels (72c) are coupled to the fixed rings (72a), the possibility exists to decouple the constructions (75, 76) by opening the closing ring (78 - see figures 13b, 13g) and by unlatching the circular bars (79) (see also figure 13g). The constructions (75, 76) can be rotated around the shafts (73) using bearings (71 ). The rotational movement of the constructions (75, 76) around the bearings (71 ) can be driven by making use of hydraulic cylinders (80), as can be seen in figure 13a, 13b, and 13f. The hydraulic cylinder (80) can be rotated around a vertical axis at the side of the cylinder by means of a bearing (81 ) placed around a vertical shaft (81 a) which in turn is fixed to a horizontal tube (75a). The hydraulic cylinder (80) can be rotated at the sides of the cylinder rod around the vertical axis by means of a bearing (82) which is displaced around a vertical shaft (82a) and is connected to one of the constructions (75, 76). A different method for rotating the constructions (75, 76) around the vertical axis is by coupling the constructions (75, 76) to ring motors (71 a) (not represented in the figures) which are used instead of bearings (71 ) and which are connected to hollow shafts (73).

After opening the clamping mechanisms (70, 70c) (see figure 13c) and opening the rotated constructions (75, 76) around the bearings (71 ) of ring motors (71 a), the framework (3a) can be moved away from the anchored windmill (1 ). In figures 13c and 13d the clamping mechanism (70) is represented. Opening the clamping mechanisms (70) takes place by means of a rotation of a ring motor (84a) that is connected to the stationary axis (83). The axis (83) is connected to the horizontal plates (39) of the tilting and clamping mechanism (5a) (see also figure 13c). The inside of the ring motor is the stator, whereas the outside of the ring motor functions as rotor, whereby a ring (85a or 85b) is coupled thereto. The ring (85a or 85b) is cobbled to one of the half cylindrical clamping parts (70a or 70b). In this case the ring motors (84a, 84b) rotate in opposite directions. Such an automated hydro-hammer driving mechanism can also be applied for windmills that need to be anchored to the bottom soil, whereby the mast and/or foundation is comprised of a lattice construction. The lattice construction advantageously comprises three or more guiding shafts at the bottom side of the lattice construction, through which the piles can be driven into the soil. The mechanism, in analogy to what has been described here before, has to be designed in such a way that after the driving of the piles the windmill and the framework (3a) can be separated, whereby the hydro-hammers (74) can be reused for a next hydro-hammer pile driving phase.

Figures 13h and 13i show a front view of a windmill (1 ) of the tripod type, to be deduced from figures 13a and 13b, with the difference that the lattice

constructions (75, 76) and all components installed thereon and connected thereto, as well as the clicking mechanism (72a-c) have been left out. The piles (77) that are clamped onto the bottom side by means of clamping/guiding mechanisms (70c) are independently driven into the soil by hydro-hammers (74) which are placed on top of the piles. After having finished the pile driving (see figure 13) the hydro-hammers (74) are hoisted on board the floating vessel by means of cables (52a) that are connected thereto, using winches aboard the vessel (not represented in figures). Subsequently, the clamps (70, 70c) can be opened and the framework (3a) removed from the anchored tripod windmill (1 ).

Figure 14a shows a front view of a windmill (2) of the mobile type, comprising a construction that is suitable for transferring the driving force of multiple,

synchronous working hydro-hammers to the mast, in such a way that a resulting driving force runs in the direction of the centreline of the windmill. The

construction in the figures is a triangular horizontal ring (72a) that is fixed with the tilting and clamping mechanism (5a), in which the conical funnel (72c) fits. As a clicking mechanism, use can for example be made of a resilient and

automatically magnet activated ball/pen mechanism. Once the conical funnels (72c) are coupled to the fixed rings (72a), the possibility exists to decouple the constructions (104 in figure 14d and 14e) that are connected to the mast. For reasons of rigidity and strength, it is useful to have the connection of the plate and the mast comprise three vertical triangular rigidity plates (104a - see figure

15a-c) originating in the three corners of the triangular plate (104). The plate (104) is driven into the bottom of the body of water by three triangularly and vertically positioned hydro-hammers (74) under the influence of a vertical driving force. In the figures 14c and 14d it can be seen that two hydro-hammers (74) are

connected to construction (91 ) and that one hydro-hammer is connected to construction (92). The constructions (91 ) and (92) are coupled to one another by means of an automatically closable eye construction (91 b) (see figure 14d). The connections between the hydro-hammers (74) and the constructions (91 , 92) are loose connections, whereby hydro-hammers (74) are slid over vertical columns which are not visible in the figure and which are fixed to one of the constructions (91 , 92). The constructions (91 , 92) rest loosely on the plate (104 in figures 14d and 15), whereby the kickback or reaction force of the soil is for the larger part taken up by the hydro-hammers (74) and partially by the inertias of the

constructions (91 , 92) and the hydro-hammers (74). To counter the reaction forces of the soil on the constructions (91 , 92) and for fixing and positioning the upper part of the mono-pile mast (3) to the constructions (91 , 92) the mono-pile mast (3) can be connected to the constructions (91 , 92) by means of a temporary clamping mechanism between the plate (104) and the constructions (91 , 92) (not visible in the figures 14a-d). The clamping action of the clamping mechanism is automatically interrupted at the end of the pile driving. For a proper functioning of the pile driving it is necessary that the driving force of the individual hydro- hammers (74) is applied to the constructions (91 , 92) in a synchronised way, and that the direction of the resulting driving force of the three hydro-hammers (74) passes through the vertical centreline of the mono-pile mast (3). The driving force of the hydro-hammers is preferably spread out evenly by means of the diagonal tubes (91 a, 92a in figure 14d) on the horizontal plate (104) of the mono-pile (2).

Figure 14c shows a front view of the lower part of the mono-pile (2), in which the hydro-hammer mechanism can be seen. The guiding of the hydro-hammers (74) takes place along the guiding columns (90) which at the top side are led through the vertical hollow shafts (93) in the corners of the constructions (91 , 92). At the bottom side, the columns (90) are led through hollow shafts (97) that are connected to the construction (98, 99), whereas the columns (90) are connected to the rings (96) which in turn are connected to the clamping mechanism (5b). The guiding and the positioning of the mono-pile mast (3) during the pile driving takes place on the lower side by means of the clamping mechanism (101 ). The formal opening clamping mechanism (101 ) is connected with the tilting and clamping mechanism (5b) by means of the axes (103) that can be seen in figure 14b. After the pile driving phase the constructions (91 , 92), the hydro-hammers (74), and the shafts (93) shall be in a position right above of the constructions (98, 99). The hollow shafts (93), comprising internal thread or internal teeth, are placed in the external thread or the external teeth of the hollow sockets (95), connected to ring motors (94). Possibly the connection between the hollow shafts (93) and the hollow sockets (95) is carried out by means of a clicking mechanism that can be seen in figure 13e and that is described with reference to figure 13. The ring motors (94) are hereby fixed to the shafts (96) which in turn are fixed to the tilting and clamping mechanism (5b). Once the couplings between the hollow sockets (95) and the hollow shafts (93) have been made, the connections between the constructions (91 , 92) and (98, 99) are undone by opening the eye mechanisms (91 b, 98b). The constructions (91 , 92), inclusive of the hydro- hammers (74) positioned thereon, are folded open around the rotation axes of the upper ring motors (94) by activating the upper ring motors (94). Simultaneously, the constructions (98, 99) are folded open around the rotation axes of the ring motors (94) that are connected to the rings (96), by activating the lower ring motors (94). The clamping mechanism (101 ) is automatically opened by activating the three double sided activated hydraulic cylinders (101 c), comprising kickback springs (102), as can be seen in figure 14b. Thereby, both halves (101 a, 101 b) are able to rotate around the axes (103) that are fixed in the tilting and clamping mechanism (5b) (see also figure 15c). After opening the constructions (91 , 92, 98, 99) and the clamping mechanism (101 ) the framework (3) can be removed from the anchored windmill comprising the mono-pile (2).

Figure 14e shows a front few of the lower part of the mono-pile mast (3), with three characterising phases (F1 , F2, F3). In phase 1 (F1 ), the mutually coupled constructions (91 , 92) with the hydro-hammers (74) connected thereto, and the shafts (93) are situated in the upper position. In phase 2 (F2), the mutually connected constructions (91 , 92) are, after the pile driving with the help of synchronised hydro-hammers (74), connected with the sockets (95) comprising the external teeth or the external thread by means of the shafts (93) comprising internal teeth or internal thread (see figure 14e - phase 1 ). To carry out the coupling of the constructions (91 , 92) with the shafts (93) with sockets (95), use can also be made of the clicking mechanism that can be found in figure 13e. In phase 3 (F3) the constructions (91 , 92, 98, 99) are rotated by means of the drivers of the ring motors (94) around the rotation axes of the ring motors (94). The constructions (91 , 92) and the shafts (93) are coupled to sockets (95) which are in turn connected to the rotors of the ring motors (94). The constructions (98, 99) are connected via hollow shafts (97) (94a) connected to the rotors of the ring motors (94). The clicking mechanism (101 ) is therefore opened by activating the double sided hydraulic cylinders (101 c - see figure 14b).

Figures 15a-c show a representation of a windmill (2) of the mono-pile type that can be derived from the windmill as represented in figures 14a and 14c, with the only difference that the lattice constructions (91 , 92) and (98, 99) and all the components connected thereto have been omitted. The mono-pile (2) that is clamped at the bottom side by means of the clamping/guiding mechanism (101 ) is driven into the soil at the top side of the foundation by means of hydro- hammers (74) that are positioned on shafts (104b) of a triangular plate (104) that is connected to the foundation. For reasons of stiffness the triangular plate (104) can be supported by reinforcing plates (104a) that are connected to the mono- pile. After the pile driving has been carried out, the hydro-hammers (74) are hoisted on board the floating vessel via cables (52a) by means of winches (not represented in the figures) that are positioned on the floating vessel. Hereafter, the clamp (101 ) can be opened by means of the double sided hydraulic cylinders (101 c) which can be seen in figure 15c, and the framework (3a) can be removed from the anchored mono-pile windmill (2).

Figure 16 shows a perspective view of a windmill that is composed of a windmill (2) of the mono-pile type, comprising a suction anchor (5). The windmill (2) is coupled to the lattice construction (4). With the exception of the constructive design of the tilting and clamping mechanism (5b), together with the foldable clamping constructions for the suction anchor (40) and the mast of the windmill (41 ) which is a part of the tilting and clamping mechanism, the constructions that are part thereof are identical to the constructions that can be seen in figures 2, 7, and 9, relating to a windmill of the tripod type. For extra buoyancy couple while tilting the windmill (2) in combination with the lattice construction (4) around the rotation axis (37) a flotation body (50) is foreseen around the mast (3) of the windmill.

Figure 17 shows a side view of a windmill (2) of the mono-pile type that is driven into the bottom of the body of water (65) by means of a hydro-hammer (74) or a pile driving installation (74) suited for the BLUE Piling Technology. With the exception of the constructive design of the tilting and clamping mechanism (5b), together with the foldable clamping construction (40) for the mast of a windmill (2), the constructions that are part thereof are identical to the constructions that can be seen in figure 12, relating to a Windmill, comprising a windmill (1 ) of the tripod type. Because of the absence of the relatively heavy generator and blades, the lattice construction (4), coupled to the mast (3) of the windmill (2), can be omitted for rigidity reasons. Figure 18 shows a side view of a windmill (1 ) of the tripod type, comprising suction anchors and coupled to a lattice construction (4). Both the windmill (1 ) and the lattice construction (4) are connected to the framework (3a) by means of the rotation axes (37) and (21 ). The constructive design is identical to the design that can be seen in figures 7, 8, and 9. The difference with the method described above is that the windmill (1 ) in this case is not immersed and lowered to the bottom of the body of water (65) together with the framework (3a). In this method the framework (3a) is lowered in a horizontal position to the bottom of the body of water (65) while the generator (7) is kept above the water surface (66) by means of a flotation body (62) coupled to the generator (7). Even without the usage of the floating body (62) the generator can be kept above the water service (66) due to the buoyancy forces of the windmill mast (1 ) and the lattice construction (4) under water. In order to overcome the buoyancy forces of the windmill mast (1 ) and the lattice construction (4) during the settling process, the foundation of the windmill can be filled with water. To immerse the framework (3a) in a horizontal position, the framework can be balanced by controlled filling of the beams of the framework (9, 10, 1 1 , 12) with water. The transverse beam (12) adjacent the clamping and tilting mechanism (5a) can for example be filled with water while the opposing transverse beam (10) is further filled with air. The immersion of the framework (3a) is carried out in a controlled manner via the cables (52) attached thereto that are reeled on the drums of winches (51 ) positioned on the floating vessel (53) (neither of them visible in this figure, but represented in figure 19). This method has as an advantage that the generator (7) does not go below the water surface. Figure 19 shows a perspective view of the way that the framework (3a) and the windmill (1 ) that is rotatably connected to the latter, and the lattice construction (4) are positioned on and anchored to the bottom of the body of water (65) by means of screw anchors (8). The generator (7) and the blades (6) float on the water surface (66) under the influence of the flotation body (62). When suitably designed the buoyancy forces of the gas filled windmill mast (1 ) and gas filled lattice construction (4) under water keeps the generator (7) preferably above the water surface (66) without using the floating body (62). Before the tripod (1 ) windmill that is rotatably connected to the framework (3a) and the lattice

construction (4) that is coupled thereto can be erected, the floating vessel (53) will have to be moved. The width and the height of the bridge (54) of the vessel are dimensioned accordingly.

After this phase the erecting couple of the tripod (1 ) windmill and the lattice construction (4) coupled thereto will be generated by the hydraulic cylinder (23) that is attached to the framework (3a) and/or the hydraulic cylinder (29) that is connected to the lattice construction (4). An additional flotation body (50) (not represented in the figure) that is connected to the windmill (1 ) and/or the lattice construction (4) can possibly create an additional erecting couple.

Figures 20a and 20b show a corner construction (6) in more detail comprising the skid (7a) and the screw anchor construction (8). In order to resist the varying load and/or the driving force on the skids (7a) or possibly on the wheels or the caterpillar tracks, a spring (1 18) is wedged in between a plate (1 16) that is connected to the skid (7a) and a plate (1 19) connected to a hollow vertical cylinder column (125) and a hydraulic cylinder (121 ). A cylindrical guiding tube (1 17) connected to the plate (1 16) can vertically skid back and forth at the inner side of the cylindrical column (125). A cylindrical tube (125) can vertically skid back and forth at the inner side of a tube (126) connected to the plates (124, 127). The blades (124, 127) are connected to the corner (15). By means of hydraulic cylinders (121 ) that are connected to the plate (124) which in turn is connected to the corner (15), the assembly consisting of the skid (7a) and the hollow vertical cylindrical tube (125) can be moved vertically. In order to inhibit the bending of the cylinder rods (121 a), the latter are connected with and surrounded by a tube (120) comprising holes that is guided around the hydraulic cylinder (121 ) at the outside. An additional advantage thereof is that in case of an impact or varying load on the skid additional damping by the in- and outflowing water through the openings in tube (120) is created. An interesting method to prevent a rotation of the skid (7a) around the z-axis can be achieved by using the counter acting rotation couple of a helical spring (1 18) that is fixed to the plates (1 16, 1 19) at both its extremities.

Figure 20b shows another possible embodiment of a means to anchor the framework (3a). Screw anchor installations (8) comprise a cylindrical hollow rigid tube (1 1 1 ) connected by means of a top plate (1 14) to two hydraulic cylinders (1 12). Around part of the hydraulic cylinders (1 12) a hollow tube (1 13) comprising openings through which water can flow, is placed in order to create extra stiffness. The tube (1 13) is at its top side connected to the top plate (1 14). At the bottom of tube (1 1 1 ) a rotatably driven screw (1 10) can be seen. The tube (1 1 1 ) can freely move vertically through the corner (1 15) and is connected to this comer (15) by means of the top plate (1 14) and the hydraulic cylinders (1 12). The tube (1 1 1 can comprise holes to permit the in- and outflow of water in order to facilitate the vertical movement of the tube. The framework beams (9, 1 1 ) and the transverse beams (10, 12) from the preceding figures 2, 3, 4, 7, 8, 9 are connected to the corner construction (6) by means of springs (131 a, 131 b) and ball joints (129a, 130a) and (129b, 130b). The springs (131 a, 131 b) and ball joints (129a, 130a) and (129b, 130b), in combination with the vertical spring (1 18) which is connected to the corner construction (6) permits the corner construction (6) six kinematic degrees of freedom in relation to the framework (9, 1 1 ) and transverse beams (10, 12). The spheres (129a, 129b) of the ball joints are connected fixedly with the transverse beams (10, 12) and the framework beams (9, 1 1 ). The bearing linings (130a, 130b) of the ball joints are split in order to be able to carry out the assembly and the disassembly of the ball joints. The tube (132a, b) which is connected to the bearing linings, can be slid in and out of the corner construction (6).

Claims

1 . Immersible framework, suited for installing a windmill on the bottom of a

body of water whereby the framework comprises of

a fixed part (3a) comprising anchoring means (8) suitable for anchoring the framework to the bottom of a body of water and supporting means (7a) suitable for letting the framework rest at the bottom (65) of the body of water, and

a tiltable part (4) comprising connecting means (33) for connecting a windmill or at least a foundation of a windmill to the tiltable part (4), wherein the tiltable part (4) is rotatably connected to the fixed part (3a) by means of a substantially horizontal axis (21 ).

2. Framework according to claim 1 , wherein a flotation body (50) is connected to the tiltable part (4).

3. Framework according to any one of claims 1 -2, wherein the framework

comprises one or more actuators (23) suitable for moving the tiltable part (4) from a horizontal position or from a position that forms an angle with the bottom (65) of the body of water towards a vertical position by means of rotation around the substantially horizontal axis (21 ).

4. Framework according to any one of claims 1 -3, whereby the tiltable part (4) comprises a lattice construction comprising linear actuators (29) which, upon activating, have an effect in the longitudinal direction of the lattice

construction (4).

5. Framework according to any one of claims 1 -4, whereby the fixed part (3a) of the framework is a rectangular framework comprising two parallel positioned framework beams (9,1 1 ), two transverse beams (10,12), and four corners (13,14,15,16), whereby the extremities of the framework beams (9,1 1 ) and the extremities of the transverse beams (10,12) are resiliently connected with a corner by means of a ball-joint (129a,129b, 130a,130b) in each of the four corners of the rectangular framework.

6. Framework according to claim 5, whereby the framework beams (9,1 1 ), the transverse beams (10,12), and/or the corners (13,14,15,16) comprise compartments that can be filled with gas and/or water in order to be able to float the framework or to immerse it into an immersed state.

7. Framework according to one of the claims 5-6, whereby the corners

(13,14,15,16) of the rectangular frame comprise the anchoring means (8).

8. Framework according to any one of claims 5-7, whereby the supporting

means (7a) are resiliently connected to the corners (13,14,15,16) by means of vertically adjustable linear actuators (121 ).

9. Framework according to claim 8, whereby the supporting means (7a) is a skid, a wheel, or a caterpillar track.

10. Framework according to any one of the claims 1 -9, comprising one or more thrusters (17a, 17b) that enable a vertical and/or horizontal movement of the framework in an immersed situation.

1 1 . Method for installing a windmill (1 ) on the bottom (65) of a body of water, whereby the windmill comprises a foundation (5e) that is suitable for being anchored to the bottom (65), and whereby the foundation (5e) is connected or can be connected with a mast (3) comprising a generator (7) and blades (6), and whereby the method comprises the following steps:

(a) connecting the foundation (5e), possibly connected with the mast (3) comprising the generator (7) and the blades (6), to the tiltable part (4) of a framework according to any one of claims 1 -1 1 ,

(b) immersing the obtained framework from step (a),

(c) positioning and anchoring the framework to the bottom of the body of water (65),

(d) moving the foundation (5e) from a horizontal position or from a position that forms an angle with the bottom (65), to a vertical position by means of a rotation around the substantially horizontal axis (21 ) of the tilted part of the framework and

(e) fixing the foundation onto the bottom (65).

12. Method according to claim 1 1 , whereby in step (a) a foundation (5e)

connected to a mast (3) comprising a generator (7) and blades (6) is connected to the tiltable part (4) of the framework.

13. Method according to claim 12, whereby in step (d) the windmill (1 ) is moved from a horizontal position or from a position that forms an angle with the bottom to a vertical position by means of a rotation around the substantially horizontal axis (21 ), whereby the movement is made possible by an upward force created by a flotation means (50) connected to the foundation or the mast, whereby the flotation means is removed after step (d) and/or by a flotation means (50) connected to the tilted part (4).