Patent Description:
In a known method for installing an offshore wind turbine having a monopile as its foundation, the monopiles are transported to the installation site on a vessel in a horizontal orientation, with the length thereof perpendicular to the length of the vessel, for example a monohull vessel, e.g. as illustrated in <CIT>.

There is a trend towards large wind turbines, e.g. of at least <NUM> MW or even more than <NUM> MW, and a desire to install offshore wind turbines at locations with rather significant water depths. Both result in larger and heavier monopile foundations. Monopiles are planned to be installed that have a length of <NUM> meters or more, e.g. <NUM> meters or more. Diameters of the monopile are in the range of e.g. <NUM> - <NUM> meters, e.g. <NUM> meters. The material for the monopile is commonly steel and the wall thickness is, for example, be in the range between <NUM> and <NUM> centimetres. The weight of such monopiles may be more than 1000mt, possibly 1300mt or above. Whilst monopile foundations are nowadays seen as efficient, the enormous dimensions and weight pose increasingly high requirements to the cranes and tools used, and increases the complexity and duration of the operation of thereof in the installation process.

The great length of the pile may in practice entails that the upper end thereof is outside of the contour of the upper or main deck when the pile needs to be upended, so the pile protrudes well outside the vessel.

By means of a heavy lift crane and a hoisting tool suspended from the crane the monopile is upended. In known embodiments, upending is done by hoisting the upper end of the monopile while the lower end thereof is being held by a pivoting upending tool, that is mounted on the vessel.

The increasing dimensions of the monopiles complicates the handling and control of the hoisting tool when positioning and connecting the hoisting tool to the upper end of the monopile.

An example of a hoisting tool used for the upending is disclosed in <CIT>. Another example is disclosed in <CIT>.

In the upending process, the hoisting tool is used to retain the upper end of the monopile during the process. Subsequently, the monopile is lowered onto the seabed. It is common to make use of a pile holder onboard the vessel, or pile gripper as this device is commonly called in the field, in order to keep the monopile vertically, e.g. to ensure that the monopile is driven vertically into the seabed during the later pile driving process. In embodiments, the pile gripper also serves as, or is combined with, a pivoting upending tool for the lower end of the monopile.

Before upending the monopile, the hoisting tool has to be connected to the upper end of the monopile. Thereto, it is first positioned relative to the monopile such as to enable it to engage the upper end of the monopile, in order for it to later retain the monopile during upending. This positioning is currently done with the aid of personnel on the deck of the vessel with the aid of manhandled cables that are connected to the hoisting tool.

From <CIT>a device is known for upending a monopile with a longitudinal direction from a support surface at an outer end. The device has a support beam which runs substantially parallel to the support surface and is connected to the support surface at a support point. The support beam guides a coupling tool to which a wall part of an outer end of the monopile can be coupled. The coupling tool is displaceable relative to the support surface with the support beam, from a clear position to a coupled position in which the monopile outer end is engaged by the coupling tool.

From <CIT> a coupling tool for connection to an outer end of a monopile for the purpose of upending the element is known. The coupling tool has engaging means with which the outer end of the element can be engaged, and a pivotable lifting member with which the coupling tool can be suspended from a lifting means such as a crane. Resilient arms are further mounted on the coupling tool, which arms can be moved from a starting position to a position against a wall part of the outer end of the element for the purpose of aligning the suspended coupling tool relative to the outer end, and for damping movements of the suspended coupling tool.

Further prior art documents are: <CIT>, <CIT> and <CIT>.

The present invention aims to provide a method and vessel, which enable an alternative way of connecting the hoisting tool to the monopile. This aim is achieved by:.

This aim is also achieved by a vessel for upending a monopile of an offshore wind turbine from a horizontal position on the vessel to an upended vertical position of said monopile, the vessel being provided with:.

An advantage of the claimed method is that the weight of the suspended hoisting tool remains supported by the crane, and is not supported by other means during the process of positioning and connecting the hoisting tool to the monopile end. As a consequence, the anti-swing device is of a lightweight construction and not equipped to support the weight of the hoisting tool.

Preferably, the hoisting tool for the monopile is attached to the crane at a parking position of the hoisting tool. Preferably, at this parking position the hoisting tool is both longitudinally and radially spaced from said monopile end, e.g. the remote position being on a deck of a vessel,.

The vessel of the invention is preferably further equipped with a pivoting upending tool engaging the end of the monopile opposite the hoisting tool, to assist the upending process.

There are alternative options to carry out the step of moving the suspended hoisting tool from the proximate position into a connection position longitudinally aligned with the monopile end, while the hoisting tool maintains being supported by the crane and engaged by the anti-swing device.

In embodiments, the anti-swing device comprises a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool, and an actuator allowing movement of the telescopic portion engaging the hoisting tool with respect to the static portion of the anti-swing device. An additional advantage of such a telescopic construction is that it allows a compact transport position.

In alternative embodiments, the anti-swing device comprises an actuator and optionally also a guide, allowing movement of the hoisting tool with respect to the anti-swing device to move the suspended hoisting tool from a proximate position into a gripping position longitudinally aligned with the monopile end, while the hoisting tool maintains being supported by the crane and engaged by the anti-swing device.

In yet alternative embodiments, the anti-swing device comprises an actuator allowing movement of the anti-swing device and the hoisting tool with respect to the vessel. This is e.g. conceivable when the anti-swing device is mounted movable to the vessel, e.g. via a gear rack.

In alternative embodiments, it is conceivable that the hoisting tool itself comprises an actuator allowing movement of the hoisting tool with respect to the anti-swing device, to move the suspended hoisting tool from a proximate position into a gripping position longitudinally aligned with the monopile end, while the hoisting tool maintains being supported by the crane and engaged by the anti-swing device.

In embodiments of the invention, the anti-swing device comprises movable monopile contact points and an actuator allowing movement of the monopile contact points with respect to the remainder of the anti-swing device, and to the vessel. After the provision of the anti-swing device along the monopile and extending beyond the monopile end, a preferred method of the invention includes the step of the actuator moving the monopile contact points from a proximate position into a connected position longitudinally aligned with the monopile end. In the connected position, the contact points prevent movements of the monopile, e.g. vessel induced movements, in particular sway and surge of the vessel. Monopiles are frequently provided with a coating that complicates gripping, also on a support, of the monopile. The additional connection of the contact points of the anti-swing device attribute to fixation of the monopile.

Hence, the anti-swing device both functions to prevent swing of the hoisting tool, and to prevent motions, e.g. caused by sway, of the monopile.

In advantageous embodiments, the monopile contact points are further used as a guide to guide the suspended hoisting tool from the proximate position into the connection position;.

In embodiments, the anti-swing device comprises a base which is mounted to the vessel and one or more pivot arms, which are pivotable about a horizontal pivot axis. Preferably, the anti-swing device engages the suspended hoisting tool and optionally also the monopile in a folded-down position.

Advantageously, such a pivotable construction allows the anti-swing device to pivot during hoisting, and as such during the start of the hoisting process to remain engaged with the monopile, e.g. with the monopile contact points, e.g. while the monopile includes an angle of <NUM>-<NUM>° with the horizontal. After this initial part of the hoisting process, the monopile is disengaged from the anti-swing device.

Another advantage of the construction with base and pivotable arms is that the anti-swing device can be transported in a vertical position.

In a possible configuration of the anti-swing device, the anti-swing device comprises two parallel arms defining between them a space for the monopile and for the hoisting tool. Optionally, these arms are telescopic arms comprising a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool, as described above.

In a possible configuration, the anti-swing device comprises a base which is mounted to the vessel and one or more pivot arms, wherein the one or more pivot arms are telescopic arms comprising a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool. Preferably the anti-swing device comprises two parallel pivot arms defining between them a space for the monopile and for the hoisting tool.

The present invention further relates to the combination of:.

The present invention further relates to the combination of an anti-swing device adapted to be mounted to a vessel provided with the crane and adapted to be provided along the monopile and to extend beyond the monopile end; the anti-swing device being adapted to engage the hoisting tool in a proximate position thereof in which the hoisting tool is longitudinally spaced from the monopile end and in which the radial contour of the hoisting tool at least overlaps with the radial contour of the monopile end, in which proximate position the hoisting tool is supported by the crane, the anti-swing device thereby preventing swing of the suspended hoisting tool; the anti-swing device being of a lightweight construction and not equipped to support the weight of the hoisting tool.

The anti-swing device advantageously comprises a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool, and an actuator allowing movement of the telescopic portion engaging the hoisting tool with respect to the static portion of the anti-swing device.

Preferably, the anti-swing device comprises two parallel arms defining between them a space for the monopile and for the hoisting tool. Possibly, the arms are interconnected at the distal end opposite the vessel. In embodiments, the arms are telescopic arms comprising a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool. In embodiments are the two parallel arms telescopic arms, having a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool.

Preferably, the anti-swing device comprises a base which is mounted to the vessel and one or more pivot arms, which are pivotable about a horizontal pivot axis. In embodiments, two parallel arms are mounted to the base, e.g. two arms interconnected at the distal end opposite the vessel. In embodiments, the pivot arms are telescopic arms comprising a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool. In embodiments are the two parallel arms telescopic arms, having a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool.

The invention is described in relation to the upending of a monopile. It is envisaged that the method, hoisting tool and anti-swing device of the invention may also be configured to, or applied for, hoisting other wind turbine components than a monopile, e.g. another type of foundation, e.g. a jacket type foundation, e.g. a wind turbine mast, a transition piece, a rotor blade of a wind turbine.

The invention is further elucidated in relation to the drawings, in which:.

<FIG> shows in cross section a vessel <NUM> according to the invention. In the embodiment he vessel is provided with a crane <NUM>, an upending device <NUM> and an anti-swing device <NUM>. The upending device <NUM> and the anti-swing device are mounted on the vessel at opposite sides thereof, such that a monopile can be received with one end in the upending device and with one end in the anti-swing device.

<FIG> depicts the crane <NUM> lowering a monopile <NUM> into a starting position, in which the monopile <NUM> is horizontally supported by the upending <NUM> device and monopile support <NUM>. The monopile is supported with a top end 2a and a bottom end 2b received in respectively the anti-swing device <NUM> and the upending device <NUM>.

The upending device <NUM> is of a type known from the prior art. It is submitted that an anti-swing device according to the invention can be used with different types of upending devices.

The pile upending device <NUM> comprises a support assembly <NUM> and a pile holder <NUM>. The pile holder <NUM> is tiltable mounted on the deck mounted support assembly <NUM>. The pile holder <NUM> is thus tiltable about a substantially horizontal tilt axis <NUM> relative to the support assembly <NUM> between a horizontal orientation, shown in <FIG>, in which the monopile is horizontally supported, and a vertical orientation, in which the monopile is vertically supported, i.e. is upended.

The upending device, more in particular the pile holder <NUM>, comprises a first ring 36a and a second ring 36b for engaging the monopile, a pile holder frame <NUM> supporting both rings, and a monopile foot end support <NUM> for engaging and supporting the bottom end 2b of the monopile.

In the exemplary embodiment shown, the second ring 36b is spaced from the first ring 36a, and at a vertical distance when the pile holder <NUM> is in the vertical orientation.

In the exemplary embodiment shown, both ring 36a and ring 36b comprise multiple pile engaging devices <NUM> distributed about the circumference of the lower ring 36a and the upper ring 36b respectively.

The foot end support <NUM> is connected with the pile holder frame <NUM> such that it is vertically below the two rings 36a,36b, when the pile holder is in the vertical orientation. The pile foot end support <NUM> is configured to engage with a foot end 2b of a monopile in order to limit longitudinal movement of the pile, at least during upending of the pile.

In the exemplary embodiment shown, the both the ring 36a and the ring 36b each comprise a ring base mounted to the pile holder frame, and two movable, semi-circular jaws. Each jaw is movable between a closed position and an opened position. When the jaws are in the closed position, the ring 36a and the ring 36b each form a closed annulus. When the jaws are in the opened position the ring 36a and the ring 36b each define a pile transfer opening. Thus, when in the opened position, the jaws allow for the pile <NUM> to be moved in a lateral direction, i.e. in a direction substantially perpendicular to a longitudinal axis of the pile, through the pile transfer opening of the ring 36a and the ring 36b into a position in the pile holder.

In the exemplary embodiment shown, the monopile support <NUM> is mounted on a track <NUM>. The track <NUM> extends along a monopile received in the upending device and the anti-swing device. Thus the positon of the monopile support <NUM> can be adapted to fit monopiles of different lengths. For example, <FIG> show the anti-swing device <NUM> and the monopile support in different working positions for respectively engaging and supporting monopiles of different lengths.

It is submitted that the crane <NUM>, shown supporting the monopile <NUM> in <FIG>, can be used for supporting a hoisting tool <NUM>, see for example <FIG>. The hoisting tool <NUM> is adapted to be supported by the crane, and is adapted to be connected to an end 2a, i.e. the top end of the monopile <NUM> while being supported by the crane. Thus, the crane <NUM> can be used for lifting the top end 2a of the monopile <NUM>, for upending the monopile while the bottom end 2b of the monopile is supported in the upending device <NUM>, and for supporting the monopile <NUM> in a vertical position.

The anti-swing device <NUM> is mounted to the vessel <NUM>. The anti-swing device is adapted to be provided along the monopile and to extend beyond the monopile end, i.e. the top end 2a of the monopile <NUM>.

The anti-swing device <NUM> is furthermore adapted to engage the hoisting tool <NUM> in a proximate position thereof, for example shown in <FIG> and in <FIG>. In the proximate position, the hoisting tool <NUM> is longitudinally spaced from the monopile, more in particular from the top end 2a of the monopile <NUM>, and the radial contour of the hoisting tool <NUM> at least overlaps with a radial contour of the monopile top end.

In the proximate position, for example shown in <FIG>, the hoisting tool is supported by the crane, not shown in <FIG>, and is engaged by the anti-swing device. The anti-swing device thereby prevents swing of the suspended hoisting tool.

The anti-swing device <NUM> is of a lightweight construction and is not equipped to support the weight of the hoisting tool <NUM>.

<FIG> shows the end of the monopile <NUM>, received in an anti-swing device <NUM> similar to the anti-swing device depicted in <FIG>, while <FIG> shows a top view of the configuration show in <FIG>. In <FIG> and <FIG> a hoisting tool <NUM>, supported by the crane <NUM>, is shown in the proximate position, in which it is in engagement with the anti-swing device.

The exemplary embodiment of the anti-swing device <NUM> comprises a static portion <NUM>, <NUM>' mounted to the vessel and a telescopic portion <NUM>, <NUM>' engaging the hoisting tool <NUM>, and an actuator allowing movement of the telescopic portion <NUM>, <NUM>' engaging the hoisting tool <NUM> with respect to the static portion <NUM>, <NUM>'of the anti-swing device.

The anti-swing device <NUM> comprises a base <NUM> is mounted to the vessel and two pivot arms <NUM>, <NUM>; <NUM>', <NUM>', which in the exemplary embodiment shown, are pivotable about a horizontal pivot axis A.

In the exemplary embodiment shown, the two pivot arms of the anti-swing device <NUM> are parallel arms <NUM>, <NUM>; <NUM>', <NUM>' that define between them a space S for the monopile <NUM> and for the hoisting tool <NUM>. Furthermore, in the exemplary embodiment shown, the two parallel arms <NUM>, <NUM>; <NUM>', <NUM>' are telescopic arms comprising a static portion mounted to the vessel and a telescopic portion engaging the hoisting tool <NUM>.

Furthermore, in the exemplary embodiment shown, the anti-swing device <NUM> comprises movable monopile contact points <NUM> and an actuator 24a allowing movement of the monopile contact points from a proximate position into a connected position longitudinally aligned with the monopile end, prior to connection of the hoisting tool, to prevent movements of the monopile, e.g. vessel induced movements.

In the exemplary embodiment shown, the pivot arms of the anti-swing device <NUM> are pivotable during the hoisting process to remain engaged with the monopile, e.g. while the monopile includes an angle of <NUM>-<NUM>° with the horizontal.

<FIG> show consecutive steps of a method of upending according to the invention, while <FIG> show a partial close up of the steps shown in <FIG> respectively.

The method comprises upending a monopile <NUM> of an offshore wind turbine from a horizontal position, shown in <FIG>, on a vessel <NUM> to an upended vertical position of said monopile <NUM>, shown in <FIG>.

The <FIG> show part of a monopile, of which the upper end is received in the anti-swing device <NUM> according to the invention. It is submitted that during the upending process, a bottom end of the monopile <NUM> is supported in a pile upending device, for example as shown in <FIG>.

The vessel <NUM>, depicted in the <FIG>, has a configuration similar to the vessel <NUM> depicted in <FIG>. The vessel <NUM> comprises a crane adapted to support a hoisting tool <NUM>, which hoisting tool <NUM> is adapted to be connected to an end of the monopile <NUM> while being supported by the crane. The vessel further comprises an anti-swing device <NUM> mounted to the vessel <NUM>, and adapted to prevent swing of the suspended hoisting tool. The vessel also comprises a pile upending device. It is submitted that the pile upending device and the crane for upending the monopile <NUM> are not depicted in <FIG>.

The anti-swing device <NUM> comprises a comprises a base <NUM> that is mounted to the vessel <NUM>, and two pivot arms of which one pivot arm <NUM>', <NUM>' is visible. The anti-swing device is furthermore provided with two movable monopile contact points <NUM> and an actuator 24a, similar to the configuration shown in <FIG>. The actuators 24a, one for each monopile contact point, enables movement of the monopile contact points from a proximate position into a connected position. It is submitted that the pivot arm <NUM>', <NUM>' is depicted in partial see-through. Therefore, one of the monopile contact points <NUM> and one of the actuators 24a are depicted in <FIG>.

<FIG> shows the monopile <NUM> being lowered by the crane onto the monopile support <NUM> and into the space S defined between the two pivot arms. In <FIG> the monopile <NUM> is received in the space S. In this configuration, the telescopic arms <NUM>', <NUM>' are longitudinally aligned with the monopile end.

<FIG> shows the monopile <NUM> being supported in a horizontal position by the vessel <NUM>, with the ends of the monopile extending beyond the vessel <NUM>. The partial see-though in <FIG> shows that the monopile contact points <NUM>, in the embodiment shown each supported by an actuators 24a in the form of telescopic actuators, for example hydraulic cylinders or electric spindles, for engaging the monopile <NUM>, do not yet engage the monopile.

The actuators 24a, one for each monopile contact point, enable movement of the monopile contact points <NUM> from a proximate position, depicted in <FIG>, into a connected position, depicted in <FIG>.

The method furthermore comprises moving, by means of the crane, the hoisting tool <NUM> into a proximate position thereof, shown in <FIG>. When in the proximal position, the hoisting tool <NUM> is longitudinally spaced from the monopile end 2a. Furthermore, the anti-swing device, by engaging the hoisting tool <NUM> in the proximate position, aids in positioning the hoisting tool with a radial contour of the hoisting tool at least overlapping with the radial contour of the monopile end. It is submitted that in the proximate position the hoisting tool is supported by the crane, and that the anti-swing device is of a lightweight construction not equipped to support the weight of the hoisting tool. Furthermore, engaging the hoisting tool <NUM> by the anti-swing device <NUM>, in the proximate position of the hoisting tool, prevents swing of the suspended hoisting tool.

Subsequently, the suspended hoisting tool <NUM> is moved from the proximate position into a connection position, shown in <FIG>. In the connection position the hoisting tool <NUM> is longitudinally aligned with the monopile end. The hoisting tool maintains being supported by the crane and engaged by the anti-swing device while it is moved from the proximate position into a connection position.

When in the connection position, the hoisting tool <NUM> is connected to the monopile end 2a, and the monopile <NUM>, more in particular the top end 2a of the monopile <NUM>, is suspend via the hoisting tool from the crane. <FIG> show the top end 2A of the monopile being suspended by the hoisting tool <NUM>.

In the exemplary embodiment of the method depicted in the <FIG>, prior to suspending the top end 2a of the monopile <NUM>, and thus prior to upending the monopile <NUM>, the telescopic arms <NUM>', <NUM>' are extended, and the telescopic actuators are extended. This allows for the contact points <NUM> to engage the top end 2a of the monopile <NUM> while the telescopic actuators 24a are in the extended position. This condition is shown in <FIG>. It is submitted that in combination with the pivotable supported telescopic arms <NUM>', <NUM>', this condition of the telescopic actuators 24a allows for the contact points 24a to keep in engagement with the top end 2a of the pile <NUM>, while the pile is being lifted along a first part of an upending trajectory. This is depicted in <FIG>. the monopile is upended by the crane lifting the top end 2a of the monopile <NUM>, while the bottom end of the monopile <NUM> is pivotable supported by the upending device. The monopile is thus pivoted about the pivot axis defined by the upending device. Therefore, the telescopic actuators 24a are retracted while the contact points <NUM> move with, and engage, the top end of the monopile <NUM>. This configuration allows for the anti-swing device to prevent, or at least reduce, axial movement of the mono pile relative to the upending device while the pile is lifted from the monopile support <NUM>. It is submitted that the anti-sing device preferably is configured to enable the contact points <NUM> to remain in contact with the top end of the monopile until the monopile is at least upended over angle of <NUM> degrees, more preferably of at least <NUM> degrees, for example <NUM> degrees.

As an alternative, or in addition, to the telescopic actuators 24A of the contact points <NUM> being retracted, the telescopic arms <NUM>', <NUM>' of the anti-swing device can be extended during the lifting of the monopile <NUM> to allow for the contact points to restrain the monopile, i.e. to prevent or at least reduce axial movement of the monopile.

After the monopile is lifted over the initial part of the upending trajectory, for example is pivoted over an angle of <NUM> degrees, or in an alternative method prior to the monopile to be lifted, the contact points disengage the top end of the monopile.

After disengaging the contact points <NUM>, the hoisting tool <NUM> is disengaged from the anti-swing device. The monopile is subsequently upended by means of the crane into a vertical position, shown in <FIG>.

<FIG> shows the vessel <NUM> in cross section, with the anti-swing device in a parking position. In this parking position, the pivotable supported telescopic arms <NUM>', <NUM>'are in an upright position. This configuration provides the anti-swing device with a minimal footprint on the deck of the vessel, when the anti-swing device is not in use. Furthermore, in the parking position the pivot arms are retracted within the contour of the vessel, which is for example beneficial when the vessel is docking in a harbour, or is in close proximity of other ships or objects.

<FIG> each show an axial view in cross section of an anti-swing device <NUM> and a hoisting tool <NUM>. The parallel arms <NUM>, <NUM>; <NUM>', <NUM>' and the actuators <NUM> are depicted in cross section.

<FIG> shows the hoisting tool <NUM> while being lowered towards the anti-swing device <NUM>. In the exemplary embodiment shown, the hoisting tool is provided with guide bumpers <NUM> configured for guiding a lower part of the hoisting tool <NUM> between the parallel arms <NUM>, <NUM>; <NUM>', <NUM>' of the anti-swing device, more in particular between the parallel actuators <NUM> of the anti-swing device.

Claim 1:
Method for upending a monopile of an offshore wind turbine from a horizontal position on a vessel to an upended vertical position of said monopile, the monopile being supported in the horizontal position by the vessel with the ends thereof extending beyond the vessel; the vessel comprising a crane (<NUM>) adapted to support a hoisting tool (<NUM>), which hoisting tool is adapted to be connected to an end of the monopile while being supported by the crane; the vessel further comprising an anti-swing device (<NUM>) mounted to the vessel, adapted to prevent swing of the suspended hoisting tool;
the method comprising the steps of:
a) providing the anti-swing device along the monopile and extending beyond the monopile end;
b) moving, by means of the crane, the hoisting tool into a proximate position thereof in which the hoisting tool is longitudinally spaced from the monopile end and in which the radial contour of the hoisting tool at least overlaps with the radial contour of the monopile end, in which proximate position the hoisting tool is supported by the crane;
c) engaging the hoisting tool by the anti-swing device, in the proximate position of the hoisting tool, the anti-swing device thereby preventing swing of the suspended hoisting tool;
d) moving the suspended hoisting tool from the proximate position into a connection position longitudinally aligned with the monopile end, while the hoisting tool maintains being supported by the crane and engaged by the anti-swing device;
e) connecting the hoisting tool to the monopile end and suspending the monopile end via the hoisting tool from the crane,
f) disengaging the hoisting tool from the anti-swing device,
g) hoisting by means of the crane the monopile end connected to the hoisting tool.