WO2023046980A1

WO2023046980A1 - Helical pile template and method thereof

Info

Publication number: WO2023046980A1
Application number: PCT/EP2022/076794
Authority: WO
Inventors: Marius Gabriël OTTOLINI; Paul Antonius Alphonsus GEENE
Original assignee: Heerema Marine Contractors Nederland Se
Priority date: 2021-09-27
Filing date: 2022-09-27
Publication date: 2023-03-30
Also published as: NL2029259B1

Abstract

The disclosure relates to a template for introducing at least one helical pile into the ground, in particular a seabed. The template comprises a base comprising a helical pile guiding device and at least one foot. The at least one foot may extend laterally away from the helical pile guiding device in at least one lateral direction. The at least one foot has a lower surface configured to rest on the seabed. The at least one helical pile guiding device is configured to guide a helical pile into the ground from an initial pile position to a target depth. The helical pile guiding device comprises - a lower passage, located at a lower end of the initial pile position and configured to allow a helical pile to pass; - at least one guiding member extending upwardly from the base; a pile connector connected to the at least one upwardly oriented guiding member and configured to be connected to a helical pile. The template is provided with one or more drives for rotating the helical pile and driving the helical pile into the seabed. The lower surface of the at least one foot may counteract the torque applied to the helical pile when driving the helical pile into the seabed. The template may be provided with one or more foundation pile guides for guiding a monopile during installation thereof.

Description

Title: HELICAL PILE TEMPLATE AND METHOD THEREOF

FIELD OF THE INVENTION

The invention relates to the field of embedding pile-like elements in the seabed at offshore locations and in particular to a device and a method for embedding pile-like elements in the seabed.

BACKGROUND OF THE INVENTION

In the field of embedding pile-like structures into the seabed at offshore locations, various devices and methods exist.

Various considerations apply to methods of embedding pile-like elements in the seabed at offshore locations. For instance, installation time is an important factor since it relates directly to the cost of the installation. Further, increases in component size also increase the cost of devices suitable to embed these large components in the seabed, because these devices have to be adapted to the size of the components. Given ever increasing size of components, such as monopiles and other foundation piles for offshore structures such as wind turbines, the installation devices have to increase in size as well.

US6273645 relates to a method for installing anchors on the bottom of the sea. Wires and a suction anchor are attached to a frame. Through the centre of the frame’s vertical axle a mounting device for an anchor holder is placed. The frame works as a driving ramp for different shaped anchor holders and anchors. With the mounting device the anchor penetrates the bottom of the sea at a certain position. A remote operated vehicle (ROV) and/or a hydraulic motor and pump gives a hydraulic torque for boring screwing, pressing and stamping effects. A helical screw-anchor is used for rotary screwing into the bottom of the sea. The span and the gradient are varied given to geological data for achieving holding forces. After use the anchor is released with a releasing mechanism and is left on the bottom of the sea.

WO-2019/057827 provides a reusable offshore installation template for the installation of offshore wind turbine foundations, in particular monopiles The template comprises a sleeve adapted to receive the monopile and guide it in the sleeve direction through the sleeve, and a support assembly comprising a base defining a landing surface and a support frame extending from the base. The installation template is adapted to reorient the sleeve direction S relative to the landing plane of the base based on a force applied to the sleeve. With ever increasing sizes of components, such as monopiles, the environmental loads on the components also increase. One major environmental load originates from waves. Forces originating from wave action may create, due to their elevation relatively remote from the seabed, a toppling effect on the component. To counter this toppling effect, typically mass is added to the template, resulting in larger and heavier templates. The large and weighed templates are able to support the component and keep the component upright due to the (additional) mass and their footprint on the seabed. However, for components exceeding a certain dimension this typically results in templates being unpractical or having unrealistic sizes. Such templates are costly and sometimes not even possible to transport or handle.

Also, the number of contractors able to install large templates is ever more limited with increasing template size. To transport and install templates, typically a semi-submersible crane vessel (SSCV) is required. The largest crane vessels worldwide, with lifting capacities in the order of 5000 to 15000 tonnes, are still limited in size, for instance to about 100 m width, and 150 to 200 m length. Template sizes are therefore limited by the handling capacity, both in size and weight, of the available crane vessels. Moreover, the number of companies worldwide having the capacity, including the availability of large crane vessels and the know-how to handle and install large structures offshore, is limited to a handful. Examples include the SSCV Sleipnir and SSCV Thialf operated by the Applicant, and alternatively the Saipem 7000 and the Zhen Hua 30.

For instance, a template as disclosed in US6273645 and WO-2019/057827 is, in practice, unsuitable for installing relatively large monopiles intended as a foundation for state of the art wind turbine generators. Relatively large wind turbines herein may include, for instance, wind turbines having one or more of a power rating of 5 MW, 10 MW, or 15 MW or more, a mast height in the order of 50 to 150 m or more, a mast diameter of about 20 m, 25 m, or 30 m or more, a blade length in the order of 80 to 150 m or more. Monopile foundations typically have a diameter substantially larger than the diameter of the mast. The length of the monopiles may be in the order of 75 to 150 m or more. Templates suitable for foundation piles for large wind turbines referenced above must be able to support the foundation pile while the pile is not yet supported by the soil. The footprint size of the template typically exceeds the diameter of the foundation pile by a significant margin.

Furthermore, because soil characteristics differ from location to location, a device may be suited for use at a first location but may not function at a second location. For example, piling in a soft soil needs different machinery and/or settings than piling in hard soil because the soil response will differ for both soils. As soil characteristics may already differ significantly over a horizontal distance of, for instance, 20 meters, one device or template may not suffice to install all foundation piles of a wind turbine project.

These considerations make it difficult to create a method and a device that is not only cost effective but is also applicable at most offshore locations.

WO199846833A1 discloses a device for installing a variety of anchors in the seabed. Among the possible anchors are anchors that are to be rammed into the ground, but also anchors that are to be screwed in. A large frame is lowered onto the seabed with an anchor located within the frame. When the frame touches the seabed, suction buckets located at extremities of the frame are activated and suck the frame into the seabed, fixing the frame relative to the seabed. Subsequently, the anchor is hammered or screwed into the seabed.

Although it appears that this method could work, in practice the device is quite expensive and demanding on the vessel and/or crane requirements. First, the use of suction buckets is generally not cost effective because they are expensive components in themselves. Besides being expensive, they also add weight to the device making it more expensive to produce and to transport to a desired location.

Once arrived at the desired location, the method must comprise the steps of lowering the system with the suction buckets through the water column. These section buckets, only having a small opening at the top, do not allow large flow to pass to the openings creating large amounts of added loading or added mass to the system as the water trapped in the suction buckets needs to start moving with the suction buckets where the motion is partly caused by a heaving motion of the crane. This load, which is typically called a dynamic load, reduces the allowable own weight of the template itself as this added mass needs to be accounted for in the calculated loading onto the crane. The same is true for retrieving the template back to the vessel. The result is that even larger capacity cranes are needed for handling of templates.

WO2012123431A1 relates to a system and method for installing subsea foundation frames to the seabed to which a variety of structures can be attached. The device can be used to secure a tension anchor to the seabed.

A device comprising jacks is lowered onto the seabed and is levelled by the jacks. Thereafter, a hole is drilled into the seabed and the drilled seabed is removed through an exhaust duct. Then, while a tension member is located in the drilled hole, the hole is filed with a cementatious grout or another solidifying material. This then anchors the tension member to the seabed and because the tension member is fixed to the subsea foundation frame, the foundation frame is fixed relative to the seabed.

This method and device have several disadvantages. By first having to drill a hole and then fill it again with a solidifying material is an inefficient and time consuming way of fixing a frame to the seabed. In addition to being time consuming, it also appears to be quite cumbersome to have to transport a solidifying material to the bottom of the sea.

US10138614 discloses a method and apparatus of manufacturing a sub-aqua foundation including: simultaneously inserting one or more first helical piles and one or more second helical piles into the sub-aqua earth via a common inserting apparatus, wherein a first helical pile has one or more clockwise helices and herein a second helical pile has one or more counter-clockwise helices.

The method of US10138614 can be used to connect a foundation for a wind turbine to the installed first and second helical piles. The method suggests that it will be possible to counter the torque of the first helical pile(s) by a similar counter-torque applied to the second helical pile(s). However, it is highly unlikely, and even unrealistic, that this method will provide suitable results in a practical application. As soil is typically non-homogeneous, soil characteristics at different locations tend to differ over a wide margin, including locations that are only a modest horizontal spacing apart. In other words, the opposing torques, in practice, cannot and will not cancel each other out, limiting the functionality of the disclosed method.

OBJECT OF THE INVENTION

It is an object of the invention to overcome at least one of the abovementioned drawbacks and to provide a method and a device for embedding pile-like elements in the seabed at offshore locations.

SUMMARY OF THE INVENTION

The disclosure provides a template for introducing at least one helical pile into the ground, in particular a seabed. The template comprises a base comprising at least one helical pile guiding device and at least one foot. The at least one foot may extend laterally away from the helical pile guiding device in at least one lateral direction. The at least one foot has a lower surface configured to rest on the seabed. The at least one helical pile guiding device is configured to guide a helical pile into the ground from an initial pile position to a target depth. The helical pile guiding device comprises: - a lower passage, located at a lower end of the initial pile position and configured to allow a helical pile to pass; - at least one guiding member extending upwardly from the base; and a pile connector connected to the at least one upwardly oriented guiding member and configured to be connected to a helical pile. The template is provided with one or more drives for rotating the helical pile and driving the helical pile into the seabed. The lower surface of the at least one foot may counteract the torque applied to the helical pile when driving the helical pile into the seabed. The template may be provided with one or more foundation pile guides for guiding a monopile during installation thereof.

According to an aspect, the present disclosure provides a template for introducing at least one helical pile into the ground, in particular a seabed, wherein the template comprises: a base comprising at least one foot, wherein the at least one foot extends sidewardly from a corresponding at least one helical pile guiding device in at least one sideward direction and comprises a lower surface configured to engage the seabed, wherein the at least one helical pile guiding device is configured to guide a helical pile into the ground from an initial pile position, the at least one helical pile guiding device comprising: o a lower passage, located at a lower end of the pile guiding device and being configured to allow a helical pile to pass through it, o at least one upwardly oriented guiding member connected to the base and extending upwardly from the base, o a pile connector movably connected to the at least one upwardly oriented guiding member, wherein the pile connector is configured to be connected to a helical pile, wherein the pile connector guides an upper end of a helical pile during the helical pile’s downward movement, one or more drives for rotating the at least one helical pile and driving the helical pile into the seabed, wherein the lower surface of the at least one foot is adapted to interact with the seabed to counteract a torque applied to the at least one helical pile when rotating the pile and driving the pile into the seabed.

In an embodiment, the pile connector is moveable along the at least one upwardly oriented guiding member, and wherein the pile connector is moveable between an upper position and a lower position.

In an embodiment, the pile connector defines a guide space with an inner diameter configured to allow a helical pile to pass through the guide space.

In an embodiment, the lower passage extends through the base. In an embodiment, the one or more drives are integrated in the at least one helical pile guiding device, in particular in the pile connector of the at least one helical pile guiding device.

In an embodiment, the base does not comprise an anchoring device configured to anchor the base to the seabed.

In an embodiment, the template comprises at least three helical pile guiding devices.

In an embodiment, when seen in top view the at least one foot has one of a triangular shape, an elliptical shape, a rectangular shape, or other polygon shape, each shape comprising a geometric centre.

In an embodiment, the base comprises at least one torque member extending away from a geometric centre when seen in top view, in particular, three torque members, wherein the at least one torque member is configured to interact with the seabed to create a countertorque when a helical pile is driven into the seabed, and wherein the at least one torque member comprises a lower surface configured to rest on the seabed.

In an embodiment, the base comprises at least three torque members, wherein at least one torque member is at least twice as long as at least one other torque member.

In an embodiment, the at least one helical pile guiding device is located at a distance from the geometric centre of the base and wherein the at least one helical pile guiding device and the at least one torque member are located on opposite sides of the geometric centre of the base.

In an embodiment, multiple helical pile guiding devices are located at a distance from the geometric centre of the base.

In an embodiment, at least one helical pile guiding device is located at each vertex of the polygon shape of the foot.

In an embodiment, each helical pile guiding device comprises multiple upwardly oriented guiding members.

In an embodiment, each upwardly oriented guiding member is a guiding rod or guiding rail. ln an embodiment, multiple guiding members are positioned around the lower passage when seen in top view and wherein the pile connector is connected to each upwardly oriented guiding member.

In an embodiment, the pile connector is connected to the at least one upwardly oriented guiding member, the connection allowing a translation but not a rotation of the pile connector, wherein the pile connector is maintained in the same orientation, in particular horizontal, by the at least one guiding member during its downward movement.

In an embodiment, the pile connector comprises a drive coupler, the drive coupler being configured to couple the drive to the helical pile, wherein the drive coupler comprises drive projections that project into the guide space and wherein the drive is configured to rotate the drive projections about a central axis of the guide space, and wherein helical pile comprises a pile coupling comprising pile projections that project outwards, wherein the drive projections engage the pile projections and the rotation of the drive projections rotates the helical pile.

In an embodiment, the pile connector comprises a connector coupling configured to be connected to the helical pile, in particular to a pile coupling on the pile, wherein the connector coupling comprises coupling projections that project outwards and wherein the drive projections engage the coupling projections and the rotation of the drive projections rotates the connector coupling, and wherein the rotation of the connector coupling rotates the helical pile.

In an embodiment, the connector coupling is configured to be connected to the upper end of the helical pile, in particular by gripping force or by form fit.

In an embodiment, the drive is incorporated in the pile connector and is adapted to move downward with the pile during the driving of the pile into the seabed.

In an embodiment, the connector coupling is detachable from the upper end of the helical pile and the lower passage is larger than the upper end of the helical pile.

In an embodiment, the template comprising at least two helical pile guiding devices, wherein at least one helical pile guiding device is oriented at a first angle of less than 80 degrees with respect to the lower surface of the foot and wherein at least one helical pile guiding device is oriented at a second angle of 85-95 degrees with respect to the lower surface of the foot, for instance at least two helical pile guiding devices being oriented at an angle of 85-95 degrees with respect to the lower surface of the foot.

In an embodiment, at least one first helical pile guiding device is at least 50% larger than another helical pile guiding device.

In an embodiment, the template is configured for guiding at least one foundation pile during the driving thereof into the seabed, the template comprising at least one foundation pile guide connected to the base and configured to accommodate a foundation pile, defining an opening through which the foundation pile can be inserted into the seabed.

In an embodiment, at least one helical pile is connected to the at least one helical pile guiding device, wherein the at least one helical pile is configured to keep the foundation pile guide in a target position and in a target orientation and to resist lateral forces acting on a foundation pile accommodated by the at least one foundation pile guide.

In an embodiment, the at least one foundation pile guide and the at least one helical pile guiding device are located at a distance from each other.

In an embodiment, the template comprises a same number of foundation pile guides as helical pile guiding devices.

In an embodiment, the template comprises at least twice as many helical pile guiding devices as foundation piling guides.

In an embodiment, each of a first number of helical piles comprise a clockwise pitch and each of a second number of helical piles comprise a counter-clockwise pitch, or wherein each helical pile comprises a clockwise pitch or counter-clockwise pitch.

In an embodiment, the first number and the second number are the same.

In an embodiment, each helical pile comprises a clockwise pitch or each helical pile comprises a counter-clockwise pitch.

In an embodiment, each foundation pile guide comprises a separate base which extends around the opening, the separate base comprising a flange or a rim. In an embodiment, each foundation pile guide comprises an upwardly facing guide plate which tapers outwardly, in particular conically outward, and is configured to guide the foundation pile into the opening.

In an embodiment, at least three helical pile guide devices enclose the foundation pile guide.

According to another aspect, the disclosure provides an assembly of a template as described above and at least one helical pile in the initial helical pile position.

In an embodiment, an upper end of the at least one helical pile comprises a pile coupling wherein the pile coupling is coupled to the helical pile guiding device via the pile connector, in particular via the connector coupling.

In an embodiment, a first lower end of at least one helical pile extends below the base and through the lower passage.

In an embodiment, the assembly comprises at least three helical piles.

In an embodiment, the template comprises at least three helical pile guiding devices and the template has a triangular shape, wherein each helical pile guiding device is located near a vertex of the triangular shape.

In an embodiment, the assembly has at least one helical pile having a first end and a second end opposite the first end, and a flexible member connected to the second end.

In an embodiment, in the assembly the flexible member comprises one or more of a cable, a chain, and a wire.

According to yet another aspect, the disclosure provides a method for introducing at least one pile into the seabed using a template, wherein the template comprises: a base comprising at least one foot extending laterally away from at least one helical pile guiding device and comprising a lower surface for engaging the seabed, wherein the at least one helical pile guiding device is configured to guide a helical pile into the ground from an initial pile position, the helical pile guiding device comprising: o a lower passage, located at a lower end of the helical pile guiding device, and being configured to accommodate a helical pile, o at least one upwardly oriented guiding member, o a pile connector movably connected to the at least one upwardly oriented guiding member, wherein the pile connector is configured to be connected to a helical pile and to guide an upper end of the helical pile during downward movement thereof, one or more drives for rotating the helical pile, wherein the method comprises the steps: a) arranging the template on the seabed, b) actuating the one or more drives for rotating the at least one helical pile and driving the helical pile into the seabed, wherein an interaction of the lower surface of the at least one foot with the seabed provides a force counteracting a torque applied to the at least one helical pile when screwing the pile into the seabed.

In an embodiment, the method comprises the steps of: disconnecting the template from the at least one helical pile, retrieving the template from the seabed, wherein the at least one helical pile remains screwed into the seabed during and after the retrieval of the template.

In an embodiment, the at least one helical pile is placed in the initial pile position prior to step a) and/or is connected to the guiding device prior to step a).

In an embodiment, the lower surface comes into contact with the seabed during step a) and the contact offers a counter torque to the drives during step b).

In an embodiment, multiple helical piles are alternately rotated.

In an embodiment, a first helical pile is rotated while a torque is applied to at least one other helical pile without rotating the at least one other helical pile.

In an embodiment, multiple helical piles are simultaneously rotated.

In an embodiment, the torque drives of respective helical piles are operated simultaneously to substantially or fully counter each other’s torque, more specifically more than 50%.

In an embodiment, during step d) the template is moved away from the seabed and the lower passage is moved over an upper end of the helical pile. In an embodiment, the template comprises at least a first helical pile guiding device being oriented at an angle of less than 80 degrees with respect to the lower surface of the at least one foot and at least a second helical pile guiding device being oriented at an angle of 85- 95 degrees with respect to the lower surface of the at least one foot, wherein during step b) a second helical pile corresponding to the second helical pile guiding device is driven into the seabed prior to the driving of a first helical pile corresponding to the first helical pile guiding device, wherein the second helical pile counteracts a moment about a horizontal axis created during the driving of the first helical pile.

In an embodiment, the template comprises at least one foundation pile guide connected to the base and configured to accommodate a foundation pile, the guide defining an opening through which the foundation pile can be inserted into the seabed, the method comprising the steps of: while the at least one helical pile is in the seabed, driving at least one foundation pile into the seabed via the opening of the at least one foundation pile guide; retrieving the at least one helical pile; and retrieving the template from the seabed.

In an embodiment, the template comprises at least three helical pile guiding devices, the method comprising the step of driving at least three helical piles into the seabed using the at least three helical pile guiding devices.

In an embodiment, the method comprises the step of keeping the at least one foundation pile guide in a target position and in a target orientation by adjusting the location of one of the pile connectors with respect to the helical pile of the respective helical pile guiding device.

In an embodiment, after getting the helical piles to a penetration depth, one or more helical piles are displaced relatively to the template without rotating the respective helical piles to bring the foundation pile guide within tolerance to the vertical, typically between 1 degrees, more specifically within 0.5 of the vertical.

In an embodiment, the template comprises a same number of foundation pile guides as helical pile guiding devices. In an embodiment, at least one helical pile comprises a first end, a second end, and a flexible member connected to the second end, the method comprising the step of driving the at least one helical pile and a part of the flexible member into the seabed, wherein the second end is at a distance below the seabed and the flexible member extends above the seabed.

In an embodiment, the drive is actuated until the second end of the helical pile is located under the seabed, in particular more than 4 meters under the seabed, more in particular more than 6 under the seabed.

In an embodiment, the helical pile is driven to a pre-determined depth and the flexible member is released after a predetermined time period by releasing the release mechanism.

In an embodiment, the second end comprises coupling means comprising a pad eye, wherein the flexible member passes through the pad eye, the method comprising the step of after a predetermined time period moving a first end of the flexible member away from the recess, pulling a second end through the recess and releasing the flexible member from the coupling means.

According to an aspect, the disclosure provides a method of introducing a monopile into the seabed using a template, wherein the template comprises: a base comprising at least one foot for engaging the seabed, at least one helical pile guide structure and at least one foundation pile guide structure, wherein the foot extends sidewardly away from foundation pile guide structure and/or the helical pile guide structure in at least one sideward direction and comprises a lower surface, at least two pile guiding devices, wherein the helical pile guide structure is configured to guide a helical pile into or out of the ground from an initial pile position, the guide structure comprising: o a lower passage, located at a lower end of the initial pile position, and being configured to accommodate a helical pile, o at least one upwardly oriented guiding member, o a pile connector connected to the at least one upwardly oriented guiding member, wherein the pile connector is configured to be connected to a helical pile, wherein the pile connector guides an upper end of a helical pile during the helical pile’s downward movement, o Two or more drives for rotating a helical pile, one monopile guiding device, wherein the guide structure is configured to guide a monopile into the ground from an initial pile position, the guide structure comprising: o a lower passage, located at a lower end of the initial pile position, and being configured to accommodate a monopile, o at least one upwardly oriented guiding member, wherein the method comprises the steps: a) lowering the template on the seabed, b) actuating the one or more drives, screwing in the at least two helical piles into the seabed, c) positioning a monopile into the guiding member d) installing the monopile into the seabed e) actuating the one or more drives, screwing in the at least two helical piles out of the seabed, f) retrieving the template from the seabed, wherein the monopile remains in the seabed during and after the retrieval of the template.

In an embodiment, the base comprises at least two torque members that extend away from a geometric centre when seen in top view, in particular, three torque members, wherein the at least two torque members are configured to interact with the seabed to create stability and/or uplift capacity and/or add stiffness when the monopile is driven into the seabed and wherein the at least two torque members comprises a lower surface configured to rest on the seabed.

When the template has been placed on the seabed without a helical pile in the initial pile position, a helical pile can be lowered towards the template. Subsequently, a helical pile may then be lowered to the template and through the guide space to arrive at the initial pile position before being driven into the seabed.

In an embodiment, the one or more drives are integrated in the at least one helical pile guiding device, in particular in the pile connector of the at least one helical pile guiding device.

In an embodiment, the template comprises three guiding devices. By being able to drive three helical piles into the seabed from a single template, operational time is reduced because the template does not need to be ’’restocked” between every pile. Accordingly, if multiple piles are desired in a single location, the multiple helical piles can be installed substantially simultaneously.

Driving a helical pile into the seabed under a first angle can be beneficial for the intended purpose, i.e. when a load that is to be connected to the helical pile is also oriented under an angle. One or more helical pile guiding devices may then be used to drive one or more helical piles into the ground to offer a reaction moment created by driving the first helical pile over a horizontal axis and can be used to keep the lower surface in contact with the seabed.

When a foundation pile is accommodated by the piling guide, lateral forces created by currents and waves apply a significant lateral forces on the foundation pile. Because foundation piles are becoming increasingly large, the forces also increase and are very well capable of toppling templates and foundation piles. By fixing the template to the seabed moment, loads acting on the foundation pile and template do not topple the template and foundation pile.

By using both a clockwise pitch and a counter-clockwise pitch, the moments that to be countered are reduced as the moments necessary to drive the helical piles into the seabed counteract each other.

BRIEF DESCRIPTION OF THE FIGURES

In figures 1A-1I, an embodiment of the template is depicted together with different possible shapes of the foot of the base.

In figures 2A-2D, an embodiment of the template is depicted during various stages of the introduction of a helical pile into the seabed.

In figures 3A-3H, the process of lowering the template on the seabed and installing a helical pile is depicted.

In figure 4A-4B, an embodiment of the template is depicted together with a helical pile.

In figure 5A-5B, an embodiment of the template is depicted wherein the helical pile has been driven into the ground.

In figure 6A-6B, the template is depicted ready to be retrieved.

In figures 7A-7B, the template is being retrieved while a helical template has been introduced in the seabed.

In figures 8A-8B, two close-ups of embodiments of the pile connector are shown.

In figures 9A-9D, an embodiment of the template is shown.

In figures 10A-10D, a side view of an embodiment of the template is shown.

In figure 11 , a top view of an embodiment of the template is shown.

In figures 12A-12C, another embodiment of the template is shown. In figures 13A-13I, the process of installation an embodiment of the template is depicted.

In figures 14A-14D, another embodiment of the template is shown in different positions.

In figures 15A-15C, a side view of an embodiment of the template is shown in different positions.

In figures 16A-16D, an embodiment of the template is shown in different positions.

In figures 17A to 17 E, yet another embodiment of the template is shown in different steps of a method of driving a foundation pile into the seabed.

Figure 18 shows a perspective view of an exemplary indication of forces acting on a template according to the present disclosure.

Figure 19 shows a perspective view of forces acting on a conventional template designed for the same foundation pile as the template depicted in Figure 18.

Figure 20 depicts a perspective view of an exemplary template and a Boeing 747 airplane side by side to provide an indication of size.

Figures 21A to 21 D show perspective views of yet another embodiment of a template according to the present disclosure, during respective steps in a method of driving a helical pile into the seabed.

Figures 22A and 22B schematically depict side views of a template with a lateral force acting on the template.

Figure 22C schematically depicts an embodiment of a template according to the present disclosure.

Figures 23A and 23B depict side views of a detail of an embodiment of a template according to the present disclosure during respective steps in a method of driving a helical pile into the seabed.

Figures 24A and 24B depict side views of a detail of another embodiment of a template according to the present disclosure during respective steps in a method of driving a helical pile into the seabed.

DETAILED DESCRIPTION OF THE FIGURES

As used herein, “seabed” (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the sea or ocean or another body of water.

A “helical pile” is a pile provided with one or more helical threads. The pile can be a solid or open, and have a square steel shaft or a round shaft, or a combination of both square and round. One or more helical plates may be welded to the outer surface of the pipe. The helical plates may be provided at least near the tip of the pile. Multiple helical plates may be provided along part of any selected part of the length of the pile. Helical piles are installed by rotating the shaft of the pile. As the shaft rotates, the one or more helical plates advance into the ground pulling the shaft with it. This action is much like a wood screw. Installation depth may be limited by soil density and practicality based on economics. Pitch and size of the helices can be designed for specific coil characteristics.

A “foundation pile” or “monopile” is a single column pile. The pile may be intended as a fixed foundation or base for a wind turbine of an offshore wind farm. The monopiles are driven into the ground to a depth in the order of 5 to 30 m. Fixed foundation offshore wind turbines are typically installed in relatively shallow waters of up to 50 to 60 metres (160 to 200 ft). Monopiles of about six metres (20 ft) in diameter can be used in waters up to 30 metres (100 ft) deep. The industry is moving towards monopiles up to 12 metres (36 ft) in diameter at 2,000 tonnes or more and lengths up to 120 m. The latter are suitable for installation in deeper water, for instance up to 100 m. The other wind turbine components are typically smaller than the monopile foundation. The industry may refer to “XXL” monopiles or“XXXL” monopiles.

Monopiles are relatively simple and cheap to manufacture, occupy moderate space on ships and are reliable. Hydraulic pile driving is currently the most widely used method of driving monopiles into the seabed. This method is also called hammering. Alternative installation technologies are currently being investigated.

Generally referring to figures 1 to 8, an embodiment of the invention is shown. Specifically, in figures 1A-1C and 2A-2D a template 10 for introducing a helical pile 40 into the ground is shown. The template 10 comprises a base 20 which in turn comprises at least one foot 22. The foot has a lower surface 24. The at least one foot 22 is configured to let the template rest on the ground via the lower surface 24 to provide a stable basis for a helical pile 40 to be introduced in the ground. In order to be able to introduce the helical pile into the ground, the template 10 comprises at least one helical pile guiding device 30. The base may extend in lateral direction away from the guiding device. The template may be a steel, welded structure. The base may be a truss structure.

The helical pile guiding device 30 is configured to guide a helical pile into the ground. The helical pile starts from an initial pile position 42. The helical pile 40 extends between a lower passage 32 and a pile connector 36. The lower passage is located at a lower end of the pile guide device 30, at a lower end 420 of the initial pile position. The pile connector 36 can be connected to an upper end of the helical pile. When the helical pile is being rotationally driven into the seabed by a drive 50 (depicted in figure 8), the pile connector 36 guides the upper end of the helical pile while the helical pile moves downward, i.e. during the pile’s downward movement. To guide the helical pile, the pile connector 36 is connected to an upwardly guiding member 34 which is connected to and extends upwardly from the base. In the depicted embodiment, the upwardly oriented guiding member comprises one or more, for instance three guiding rods 342. The pile connector 36 is moveably connected to the guiding member and can slide along the guiding member. The pile connector can move between an upper position 362 and a lower position 364. Herein, the lower position corresponds to a position where the helical pile 40 has been driven into the seabed to a desired depth, also referred to as target depth.

In the top view of figure 1C, multiple guiding members are positioned around the lower passage 32. The pile connector 36 is connected to each upwardly oriented guiding member 342. Because the pile connector 36 is connected to the upwardly oriented guiding members 342, the connection allows translation of the pile connector along the guiding members, but does not allow rotation of the pile connector with respect to the template. Herein, during the downward movement of the pile connector 36, the orientation of the pile connector is maintained.

Because the rotational driving of the helical pile requires a torque to be applied to the helical pile 40 by the drive 50, a reaction torque must also be delivered. Otherwise the template would spin around a static helical pile. The lower surface 24 of the base 20 delivers this countertorque through a surface interaction with the ground.

Generally referring to figures 3 to 7, an operational process of the invention is depicted. From a vessel 70, the template 10 is lowered into the sea and is suspended from a crane by crane cables 72. The template is lowered onto the ground 1. Hereafter the crane may be disconnected from the template. Subsequently, a helical pile 40 is introduced in the template by lowering the helical pile through a guide space 38 defined by the pile connector. The guide space has an inner diameter 382 (depicted in figure 1 B) which allows a helical pile to pass through the guide space 38 and into the initial pile position 42.

It will be understood that the process of placing a helical pile 40 in the template may also be performed prior to the lowering of the template on the ground, i.e. lowering the template with a helical pile already in the initial pile position. Accordingly, a helical pile may also be placed in the initial pile position prior to placing a pile connector 36 without the guide space on top of the helical pile and connecting the guiding device to the helical pile. The template and the helical pile in the initial position can be seen to form an assembly. After the helical pile 40 has been placed in the initial pile position 42 and the crane has been disconnected, the drive may be actuated screwing in the helical pile into the ground 1 through the lower passage 32 that extends through the base. Thereafter, the template can be disconnected from the helical pile and can then be retrieved from the seabed.

As can be seen in figures 7A and 7B, the helical pile 40 can remain screwed into the seabed during and after the retrieval of the template. Here, an upper end of the helical pile 40 protrudes out of the seabed 1. the penetration depth is a matter of choice.

Because the base 20, in this embodiment, lacks an anchoring device that is configured to anchor the base to the seabed, the process of lowering and retrieving the template after a pile has been introduced into the seabed can be performed much more efficiently with respect to a device that needs the anchoring to be able to work. Where for the invention it is simply a case of placing the template on the seabed and lifting it up after the introduction of the helical pile, for a device with anchoring needs, the template would have to carry anchoring devices which cost money, weigh more than necessary, and add time to operation.

In figure 1C, the base 20 is shown to comprise a foot 22 being of a substantially triangular shape, the triangle having a geometric centre 26. In the depicted embodiment, the guiding member 30 and the helical pile 40 are located at this geometric centre 26. Other polygonal or elliptical shapes may also be used. The foot defines three torque members 28A, 28B, 28C that extend away from the geometric centre 26. Here, these torque members are a portion of the foot that extend to the vertices of the triangle shape. When the torque members 28 are in contact with the seabed, they are configured to create a counter-torque to the drive 50.

Referring to figures 1 D to 11, schematic top views of different embodiments of the template are depicted. The foot 22 of the template is shown to be of a rectangular shape in figure 1 D and the guiding device 30 is located near an end of the rectangular shape. In figure 1E the foot is of a square shape and the guiding device 30 is located at a geometric centre 26. In both figures, the torque members 38 are embodied by the part of the foot 22 extending towards the vertices of the rectangular and square shape.

In figures 1 F and 1G, the foot 22 is of an elliptical shape, in particular the shape being circular in figure 1 F. In both figures, the guiding device 30 is located at the geometric centre 26. For figure 1 F, the entire circular shape is considered to be a torque member 38 because each portion of the circular shape equally contributes to the potential counter-torque. For the elliptical shape of figure 1G, the torque members 38 are embodied by the part of the foot 22 extending towards the vertices of the ellipse.

Figure 1 H depicts a foot 22 of a triangular shape wherein the guiding device 30 is not located at the geometric centre 26 of the triangular shape. The torque members 38 are embodied by the part of the foot 22 extending towards the vertices of the triangular shape.

In figure 11, a base 20 is depicted comprising at least three torque members 38A, 38B, 38C. At least one thereof, torque member 38C, may be at least twice as long as the other torque members 38A, 38B. Herein, the at least three torque members all provide stability for the template. One torque member 38C provides a significant part of the counter-torque delivered when the drive 50 is activated. In doing so, the template can be kept as lightweight as possible. The base may comprise a respective foot provided at the radial end of each torque member.

Generally referring to figures 9-11 , in another embodiment the template 10 comprises multiple guiding devices 30A, 30B, 30C. In this embodiment, the template is configured to introduce multiple helical piles into the seabed in a shorter timeframe than a template with one guiding device would be able to. Each guiding device 30A, 30B, 30C is located at a distance 204A, 204B, 204C from the geometric centre 26 of the base and each guiding device is located at an opposite side of the geometric centre 26 relative to a torque member 38A, 38B, 38C. For each guiding device, this offers the largest amount of counter-torque that each of the torque members can deliver.

To further maximise this counter-torque, each guiding device 30A, 30B, 30C is located at a vertex of the triangular shape of the foot 22. Similarly to the embodiment where the template comprises a single guiding device of figures 1-7, each guiding device comprises multiple guiding members embodied by a guiding rod 342A, 342B, 342C. In order to stiffen the template, diagonal members 207 are fixed to a centre member 206 to create a structure extending upwardly from the template. The formed triangular structures provide a stiffer structure.

During the installation of the helical piles 40A, 40B,40C, the respective drives of each of the guiding devices 30A, 30B, 30C may be operated simultaneously or alternately.

Referring to figure 8A, a close-up of a cutaway section of the pile connector 36 is depicted. Here, a helical pile 40 has been placed in the initial pile position 42 through the guide space 38. The drive 50 of the template, being integrated in the pile connector of the helical pile guiding device, comprises a drive coupler 52 which is configured to engage a pile coupling 44 fixed to the helical pile 40. The drive coupler 52 enables the drive 50 to rotate the helical pile 40 screwing it into the ground.

The drive coupler comprises drive projections 522 that may project into the guide space, wherein the drive is configured to rotate the drive projections 522 about a central axis 7 of the guide space. The pile coupling 44 of the helical pile comprises pile projections 422 that project outwards from the helical pile. The drive projections 522 may engage the pile projections 442 so that when the drive projections are rotated, the pile projections 442 are also rotated, in turn rotating the helical pile.

Figure 8B depicts another embodiment wherein the pile connector 36 comprises a connector coupling 366 being connected to the helical pile. Herein the connector coupling comprises connector projections 368. The drive projections 522 of the drive engages the connector projections 368 and, when the drive 50 is activated, rotates the connector coupling 366 which in turn rotates the helical pile 40, screwing the helical pile into the ground. The connector coupling 366 may be form fit to the helical pile 40 or can also grip the helical pile by force.

The pile projections, drive projections, and/or connector projections may have a square or triangular shape for the pile projections and/or the connector projections to engage on the drive projections. Other shapes are also possible.

In both figures, the drive 50 is shown to be incorporated into the pile connector 36 and moves downwards with the pile during the driving of the pile into the seabed. It will be understood that the drive 50 does not need to be incorporated with the pile connector 36. The drive be an electric or hydraulic drive, the drive may also be a pneumatic drive.

In order to be able to leave a helical pile in the seabed (as depicted in figures 7A and 7B) the connector coupling is detachable from the upper end of the helical pile and the lower passage of the template is larger than the upper end of the pile. In doing so, the helical pile may pass through the lower passage 32 of the template and thereafter the template can be disconnected from the helical pile.

Referring to figures 12A-12C, another embodiment of the invention is depicted. In the depicted embodiment, a first helical pile guiding device 30A is oriented at a first angle 3 with respect to the lower surface 24 of the foot 22. The first angle may be in the range of about 30 to 60 degrees. The first angle 3 may be approximately 45 degrees. In doing so, a helical pile 40A can be inserted into the ground under an angle. This may be beneficial in the case where, after installation of the helical pile in the seabed, a load will be applied to the helical pile under an angle.

The base 20 may be provided with one, two or more second helical pile guiding devices 30B, 30C. The second guide structures 30B, 30C may be connected to the base 20 near the lower passage 32A of the first guiding device 30A. The second guiding devices 30B, 30C are oriented at a second angle 5 with respect to the lower surface 24 of the foot 22. The second angle 5 may be approximately 90 degrees. The second guiding devices 30B, 30C may be smaller than the first guide structure 30A. For instance, the second guide structures 30B, 30C may be more than twice as small as the first guiding device 30A. The second guide structures may be configured to temporarily fix a side of the base 20 or the foot 22 to the seabed. In doing so, the driving of a helical pile 40A will not force the template to topple over in a direction opposite to the driving distance.

Referring to, for instance, Figures 13G to 131, a first helical pile 40A may have a first end 400 and a second end 402. The helical pile 40A may be provided with one, two or more helical sections 404. Each helical section may comprise a helically shaped plate attached to an outer surface of the pile 40A. The plate may extend radially outward from the pile over a predetermined distance. Said distance may be set depending on soil characteristics. Each helical section may have a respective pitch, and pitch orientation.

A flexible member 406 may be connected to the second end 402. The flexible member 406 may include, for instance, a cable, a wire, a flexible tube, or a combination thereof. The flexible member 406 may be connected to the second end of the pile 40A using a coupling device. The coupling, or coupling device, may comprise a pad eye. Herein, the flexible member may pass through the eye of the pad eye.

In figures 13A-13I the process of introducing the helical pile 40A into the seabed is depicted. Herein, the template 10 is lowered onto the ground 1. The two additional helical piles 40B, 40C are driven into the seabed to fix the template to the ground. Subsequently, as can be seen in figure 13D, the helical pile 40A is driven into the seabed through the lower passage 32A. Herein, the two second or additional helical piles 40B, 40C counteract a moment about a horizontal axis created during the driving of the first helical pile 40A. When the helical pile 40A has been introduced in the ground 1 to a desired depth, a coupling connector 366A can be disconnected from the first helical pile 40A and is retracted. The disconnecting may be achieved by rotating in a different direction, by disengaging the connector, or by retracting the connector. Other manners of disconnecting are also conceivable. Subsequently, the second helical piles 40B, 40C can be retracted and the template is retrieved, as depicted in figure 131.

The method depicted in figures 13A to 131 allows to insert the at least one first helical pile 40A with its second end 402 below the sea bed. Herein, the drive to rotate the first helical pile 40A may be actuated until the entire first helical pile 40A, and optionally a part of the flexible member 406, are located under the seabed 1. When installed, see for instance Fig. 13H, the second end 402 of the first helical pile 40A may be located a predetermined distance below the seabed 1 . Herein, the flexible member 406 extends from the helical pile 40A to above the seabed. The flexible member may typically be attached to, for instance, a floating structure such as a vessel, a semi-sub, a tension leg platform, or a spar. Thus, the combination of the helical pile 40A and the flexible member 406 may function as an anchor and anchor line.

The drive may be actuated until the second end 402 of the first helical pile is located under the seabed. For instance, the second end may in the installation position be more than four (4) meters under the seabed 1 , for instance more than 6 m under the seabed. The first helical pile 40A may be driven to a pre-determined target depth. Target depth herein may relate to the predetermined depth of the first end 404.

In an embodiment, the flexible member 406 may be released from the helical pile 40A after a predetermined time period. Releasing the flexible member may involve a release mechanism. For instance, after a predetermined time period, the flexible member 406 may be moved away from a recess, pulling a second end through the recess and releasing the flexible member from the coupling means.

Referring to figures 14 and 15, another embodiment of the invention is depicted. Herein, the template 10 is configured for guiding of at least one foundation pile 60, for instance a wind turbine foundation pile 60, during driving of the at least one foundation pile into the seabed. Because wind and wave forces can easily topple over such a template, the template comprises a centrally located helical pile 40 that is connected to a helical pile guiding device 30.

When the template 10 is located on the seabed, the helical pile 40 can be introduced into the ground and can offer a counter force when a lateral force would act on the foundation pile 60. Because the forces interact with each other to create an equilibrium of moments, the piling guides 62A, 62B, 62C and the helical pile guiding device 30 may be located at a distance 64 from each other.

After the template has been placed on the seabed, a foundation pile 60 may be lowered into one of the foundation pile guides 62A, 62B, 62C that are connected to the base. In figure 15A, a foundation pile has been lowered into a through opening 622 of the piling guide 62C. The foundation pile guide may comprise an upwardly facing guide plate 68 that tapers conically outward. The guide plate enables the foundation pile 60 to be easily inserted into the foundation pile guide sleeve 62B.

Such a construction facilitates the guiding of the foundation pile into the through opening. After the placement of the foundation pile 60 in the template 10, the foundation pile may be driven into the seabed using a pile driving device (not depicted). After the piling of the foundation pile 60, the template may be retrieved from the seabed. To this end, the helical pile 40 that has been driven into the seabed may first be retracted and retrieved together with the template.

In doing so, the at least one helical pile is configured to keep the piling guide in a target position and in a target orientation and to resist lateral forces acting on a foundation pile accommodated by the at least one piling guide.

Referring to figures 16A-16D, in an embodiment the template comprises multiple helical pile guiding devices configured to secure the template to the seabed. For each foundation pile guide 62A, 62B, 62C, there may be at least two helical pile guiding devices that are located near the piling guides 62A, 62B, 62C.

In the embodiment of figure 16A, if a lateral force would acton a foundation pile accommodated by, for instance, piling guide 62B in the direction of the geometric centre 26 of the base, without the guiding devices located next to the piling guide 62B, the piling guide 62B would disengage from the seabed. The template could topple over in the direction of the lateral force. If a force would act on said foundation pile in the other direction, the guiding devices near the other piling guides 62A, 62C would offer a maximum counter moment because they are located as far away as possible from the piling guide 62B, creating the largest possible lever arm.

Here, an assembly is created comprising the template and the helical pile guiding devices. The template may have a triangular shape, wherein each helical pile guiding device is located near a vertex of the triangular shape. ln an embodiment, the template comprises multiple helical pile guiding devices. Because the rotation of a helical pile into the seabed requires a counter-torque applied in the base, a pitch of a first number of helical piles can be clockwise while a second number of helical piles comprise a counter-clockwise pitch. By letting pairs of helical piles with opposite pitches rotate simultaneously the torque needed to screw both helical pairs of a pile in is in equilibrium.

Using helical piles that all have a clockwise pitch or all have a counter-clockwise pitch, all rotation directions can be kept identical. By adding torque to one or more piles without rotating them, another pile may be driven into the ground. In doing so, the torque applied to a first helical pile can be countered by a torque applied to a second helical pile. This reduces the amount of shear stress on either one of the helical piles.

As described herein, a helical pile may be a pile having a helix or thread. The thread may extend along the entire length of the respective pile. Alternatively, the thread may extend along a part of the length of the pile, wherein another part of the pile may lack a threaded outer surface.

In the embodiments depicted in figures 14 to 16, all the foundation pile guides comprise a separate base 66A, 66B, 66C that extends around the through openings 622A, 622B.

Figure 17A depicts an embodiment of the template 10 comprising a base 20. The base may comprise a truss structure. The base 20 may have any shape in top view, for instance one of the shapes as shown in Figures 1C to 1 i. Radial ends of the truss structure may be provided with a respective helical pile drive structure 30. The base 20 may, for instance, have a substantially triangular shape in top view. The base may comprise three helical pile drive structures 30A to 30C, one on each end. Each helical pile drive structure may comprise a foot 22. Figure 17A shows three feet 22A to 22C. Each foot may comprise a lower surface adapted to engage the seabed. Each foot 22, 22A - 22-C may have a shape as shown in, for instance, Figures 1C to 1i.

The respective feet 22A to 22C may surround a foundation pile guide structure 62, also referred to as piling guide or pile guide structure. The foundation pile guide 62 may comprise a sleeve like structure for guiding a foundation pile 60. The upper end of the sleeve may be provided with a conical pile receiving section 68, similar to the structure described with reference to Fig. 14A. A lower end of the foundation pile guide structure may be provided with a foot structure 66 adapted to engage the seabed. The lower ends or lower surfaces 24 of the respective feet 22A - 22C and 66 may also be referred to as mud mats. Said lower surfaces are designed to engage the seabed and, during driving in or out of any of the piles 40A-40C and 60, to provide an upward force and counter-torque for balance and stability.

The base 20 may interconnect respective helical pile guide structures 30A, 30B, 30C and the centrally located foundation pile structure 62. The truss structure of the base 20 is typically designed to create stability and structural strength up to a predetermined specification, while allowing wind and water to pass through to limit lateral force and to limit structural steel.

The template 10 is configured for guiding a foundation pile 60 during driving thereof into the seabed 1. Herein, the multiple helical pile guide structures enclosing the foundation pile guide 62 allow to anchor the template 10 to the seabed 1 using multiple helical piles 40A, 40B, 40C. Thus, the template 10 can be secured to the seabed 1 even better than the embodiment shown in Figure 14A.

When the template 10 is located on the seabed, one or more helical piles 40 can be introduced into the ground. The helical piles in effect anchor the template to the seafloor. Thus, the helical piles can counteract a lateral force acting on the foundation pile 60. Because the forces interact with each other to create an equilibrium of moments, the foundation pile guide 62 and the helical pile guiding devices 30A to 30C may be located at a mutual horizontal distance 64. The distance, which functions as an arm to provide a suitable counter momentum, can be pre-determined and designed to provide a momentum of choice. During use of the template, the mud mats (the lower surfaces of the feet 22A to 22C) counteract forces directed in downward direction, engaging the seafloor. The anchored helical piles counteract forces directed in upward direction.

Figures 17A to 17E show exemplary steps of a method to drive a foundation pile 60 into the seafloor. Referring to Fig. 17A, in a first step, the template 10 is positioned on the seabed 1. When the template is in the target position, the lower surfaces of the feet 22A to 22C, and optionally of foot 66, engage the seabed 1.

Referring to Fig. 17B, in a second step, one or more helical piles 40A to 40C are inserted in the seafloor 1. Inserting the helical piles, and respective parameters thereof such as target depth, diameter of the piles, and technical functionality of the helical pile guide structures 30A to 30C, can be equivalent to embodiments described above. ln an embodiment, the torque drives 36A to 36C can be configured to either substantially or fully counter each other’s torque. For instance, the torque drives 36A to 36C can cancel the torque of a respective other drive by more than 50%.

When the helical piles 40A to 40C have reached a target depth, also referred to as penetration depth, one or more of the helical piles may be displaced relatively to the template 10 without rotating the respective helical pile. Displacing the template with respect to the helical pile can be done by, for instance, movement of the respective drive 36A to 36C in linear fashion along the respective guide structure 342. Thus, the orientation of the frame 20 and the template 10 can be adjusted. The latter allows to adjust the position and orientation of the monopile guiding frame 62, and thus the monopile in said frame, within a pre-determined range. Said range may typically be with a pre-set tolerance with respect to vertical. Said predetermined range may be, for instance, in the order of +/- 0.5 degree, +/- 1 degree, +/- 2 degrees, +/- 3 degrees, +/- 4 degrees, or +/- 5 degrees. Herein, please note that such as slight change in orientation may result in significant horizontal displacement of the upper end of the relatively long monopiles (up to 100 m).

Another option to change the orientation of the foundation guide structure(s) 62 is shown in Figure 20. Herein, each foundation guide structure 62 may be provided with one or more hydraulic cylinders. Increasing and/or decreasing the length of the cylinders may allow to adjust the orientation of the monopile guides 62 within the range indicated above. In addition, the foundation pile guide 62 may be provided with upper and lower centralizer structures, included in the internals of the guide structures 62. The latter may allow a further adjustment of the orientation of the monopile, with a range of typically +/- 0.3 to 0.5 degrees.

Referring to Figure 17C, in a third step, with the helical piles 40 anchoring the template 10 to the seafloor 1 , the at least one foundation pile 60 is driven into the seabed 1. Herein, the helical piles 40A to 40C can counter uplift at their respective locations, while the respective mudmats of feet 22A to 22C take the downforce.

When the foundation pile 60 has reached a target depth, subsequently the one or more helical piles may be retrieved. Referring to Figure 17D, the respective drives 30A to 30C can be used to reverse the rotation of the helical piles 40 and retrieve the piles from the seabed 1.

In a next step, see Fig. 17E, the template 10 can be lifted and removed, leaving the foundation pile 60 in the seabed 1. The helical piles 40A to 40C can be retrieved together with the template. ln the method of the disclosure, the one or more helical piles anchor the template to the seafloor. By keeping the template stable, the helical piles thereby keep the foundation pile guide structure 62 in a target position and in a target orientation. The helical piles may also resist lateral forces acting on the foundation pile.

The embodiment of Figure 17A is, for instance, suitable for piling of relatively large diameter foundation piles 60, while the template 10 itself can still be relatively slender. In a practical embodiment, limitations may be set by the available crane vessel. The largest SSCVs have a breadth and length in the order of 70 to 100 m by 150 to 200 m. The available vessel would have to be able to handle (i.e. transport, lift, and install) the template. Consequently, the template may have a width and length more or less in the order of 100 m, and a height up to about 100 m. Within these margins, the template of the present disclosure can be designed for the installation of monopiles having a diameter up to about 10 m to 25 m. The template is suitable for XXL monopiles having a height in the range of 50 m to 130 m, as the helical anchor piles can be designed and dimensioned to provide appropriate counterbalance and anchoring force to keep the monopile upright during installation.

Referring generally to figures 18 and 19, exemplary impact of the environment on the template 20 during use is indicated, for the template of the present disclosure (Fig. 18) and a conventional template 20’ (Fig. 19) lacking helical piles, designed for the same component, i.e. foundation pile 60. During installation of the foundation pile, the environment acts on the monopile, with a resultant force. Please note that forces as referred to herein are a sum of forces acting on the entire component, such as monopile and template. For simplification and as example, only the averaged sum of all forces acting on a component have been indicated. In practice, the forces as referenced are not constant, but dynamic and typically vary within a certain range all the time. The variation of said force may be directional as well as in amplitude. The range and maximum amplitude of respective forces may depend on weather, including wind and wave height.

Referring to Fig. 18, during the process of driving the monopile into the seabed, for instance waves, current and wind may act on the monopile 60, providing a lateral force on the monopile, indicated by arrow 700. To keep the foundation pile 60 and the template 10 in the same position, counter forces must be provided. Shear forces 702 are indicated, provided by interaction of the mudmats, i.e. the lower surfaces 24 of the respective feet 22 of the template, with the seabed. The template also counteracts the moment acting on the foundation pile and template. Herein, at least one foot 22 interacts with the seabed to provide a force 704 in upward direction, i.e. an upforce of the respective mudmat pushing against the seabed and the seabed resisting the mudmat from penetrating the seabed. At least one or more of the helical piles 40 resist uplift and provide a force 706 in downward direction. In conjunction, the upforce 704 and downforce 706 counteract the momentum and keep the template and the foundation pile 60 upright.

Fig. 19 shows an exemplary template 10’, lacking helical piles and designed for a foundation pile 60 having similar dimensions as the foundation pile of the template 10 of Fig. 18. Herein, to provide similar shear forces 702, the respective feet 22’ have to be significantly larger. Vis, only the engagement of the mudmats 24’ with the seabed provides the shear force, without the contribution of the helical anchor piles. Also, the moment of a lateral force 700 of similar magnitude as shown in Fig. 18 would have to be counteracted by a significantly larger upforce 710 and a correspondingly large downforce 712’. The upward force 710 would require a larger mudmat, i.e. a larger lower surface of the respective foot 22’. To provide the downward force 712, typically mass would have to be added to the template 10’.

Thus, the template 10 of the present disclosure can be more slender and have smaller mudmats relative to conventional systems. Also, conventional systems typically depend on a time window wherein the weather and/or waves are calm, so that the forces 700 acting on the foundation piles remain within a safe window of operation. Said window would, in practice, have to exceed, for instance, at least 36 hours to allow the entire operation to be completed. For the template 10 of the disclosure however, the weather window can be significantly reduced. In a practical embodiment, it may take about 1 hour to insert the helical piles in the seabed. Thereafter, the template 10 has been stabilized. The template 10 with the helical anchor piles 40 inserted in the ground can withstand much larger forces 700 acting on the foundation piles 60. Thus, compared to conventional templates, limitations imposed by weather can be significantly relaxed and the window of operation can be extended accordingly.

In a practical embodiment, sizes and weight of a template with and without helical piles may differ significantly. A template 10 with feet provided with helical anchor piles can be 10% to 20% or more lighter than a comparable template. The surface area of the respective feet can be about 20% to 40% of the area of the mudmats of a comparable conventional template. In a practical embodiment, the diameter of the feet can be reduced in the order of a factor 3, while the surface area of the feet can be reduced in the order of a factor 9.

As an example for calculations for a conventional template 10’ without helical anchor piles:

Herein, ‘MP-OD’ indicates the outer diameter of the monopile, ‘MP length’ indicates the length of the monopile, ‘MP mass’ indicates the mass of the monopile in metric tons (1 MT is 10³ kg), ‘Sub Weight’ indicates the weight of the template when submerged (i.e. the weight that at some point during installation will have to be countered by the hoisting system), mudmat area indicates the surface area of the lower surface of the feet (in this example, the template has 6 feet of about 100 m² each), and template width is the width of the template measured from the middle of respective feet at opposite ends of the template. Fields 1 and 2 refer to exemplary projects for the installation of a number of wind turbines offshore.

As an example for a template 10 with helical anchor piles, for the same two exemplary fields:

To provide an indication of relative size, Figure 20 shows a perspective view of an exemplary template 10’ (without helical anchor piles), depicted next to an airplane 750. The airplane depicted is a Boeing 747, having dimensions in the order of: Wing spang 65 m (211 ft); height 19.40 m (63 ft); overall length 71 m (232 ft). The relative size provides an impression not only of the size of the template overall, but of the surface of the feet as well. The latter may provide, for instance, challenges during lifting operations, for instance when crossing the surface of the water, as explained herein below.

Wave height herein may be indicated using a significant wave height H_s. The significant wave height (SWH or H_s) is defined traditionally as the mean wave height (trough to crest) of the highest third of the waves (H1/3). Nowadays it is usually defined as four times the standard deviation of the surface elevation - or equivalently as four times the square root of the Oth- order moment (area) of the wave spectrum. The symbol H_mo is usually used for that latter definition. The significant wave height may thus refer to H_mo or H_s. The difference in magnitude between the two definitions is only a few percent. SWH is used to characterize sea state, including winds and swell.

In addition to weight and size, workability is also an issue with conventional templates. The example above shows that mudmats for a conventional template have a large surface. Mudmats might affect the workability during the template handling. Selecting a subsea template as an installation aid is not only a matter of crane static load. All the handling phases need to be thoroughly investigated before considering it as a workable solution. The following aspects, for instance, may have to be taken into consideration:

• Dynamic amplification factor (DAF) when crossing the splash zone;

• DAF when template mudmats are just below the free surface;

• Crane side-lead and crane off-lead during lowering, since large pitch and roll motions are expected.

In offshore construction, the splash zone is refers to the transition from air to water when lowering heavy objects into the sea. The overall load applied on the hoisting system may change dramatically when the load starts touching the water, up until the load is completely submerged. Buoyancy reduces the static mass that the crane has to support, but contact with the waves creates widely fluctuating dynamic forces. Simulation of these changing efforts are necessary to correctly dimension cranes and lifting equipment.

Some particular phenomena occur when the large mud mats are lowered through the splash zone. Vertical slamming arises when the water collides with the mud mats. The latter may initiate a jump in vertical velocity, resulting in oscillation in the crane. Simulations have been performed for a predefined set of wave combinations. The randomness of the irregular waves is taken into account by performing multiple simulations per wave combination, each using different initial conditions. For mud mats exceeding a certain size and area, a zero crossing period of a few seconds may result in resonant behaviour with the waves, causing unacceptable slack and load cable DAF values to exceed the maximum allowable value of 1 .3.

The template of the disclosure, with significantly reduced mud mat area, resulted in acceptable DAF values up to at least significant wave heights of 2 to 2.5 meters, and wave periods longer than 8 seconds. Significantly reduced herein may mean a reduction with a factor 9 (in area) or factor 3 (in cross dimension of a respective foot) for a template designed for the same seabed location. Herein, Dynamic Amplification Factor (DAF) or Dynamic Increase Factor (DIF) is a dimensionless number which describes how many times the deflections or stresses should be multiplied to the deflections or stresses caused by the static loads when a dynamic load is applied on to a structure. When lifting an object during a sub-sea operation, the DAF is calculated based on dynamic hydraulic forces or on snap-forces:

DAF = F_totai / (M*g).

Herein M is the mass of the object in air [in kg], and g is the acceleration of gravity (about 9.8 m/sec²). Ftotai [N] is the largest of F_stati_C.max + F_hyd or F^ic-max + F_snap. For details of this formula and many more related impacts of marine operations, reference is made to, for instance, “MODELLING AND ANALYSIS OF MARINE OPERATIONS”, edition April 2011 , as published by DET NORSKE VERITAS (DNV) of Norway.

The template of the invention has a reduced mass. In itself the mass reduction already provides benefits and simplifies handling. In addition, by the significantly reduced area of the respective feet, also the added mass (on the lifting system) when crossing the splash zone due to interaction of waves and feet surface, is significantly reduced. Thus, in combination, not only does the template provide benefits, the template may in fact provide a viable solution to install the largest monopile foundations currently envisaged, whereas conventional templates would not present a viable option as they would exceed lifting capacity of virtually every existing crane vessel.

To provide sufficient resistance to the torque, the one or more mudmats may be designed to embed in the soil and remain embedded. The mud mat may even be embedded more with increasing penetration of the helical pile in the soil. The latter is because the torque required for penetration increases with increasing penetration depth, due to the increase in resistance by an increased surface embedded.

Several options are available to embed the mud mats in the seabed. Industry standard is to use (own) weight to push the mudmat into the ground. Conventional applications could involve for instance the addition of a steel weight, in practice of up to 50 tonnes, to each foot of the template. As the present disclosure aims to reduce the weight of the template, this may not be the option of choice. Moreover, the additional offshore heavy lifting operations required to lift and retrieve the weights, for instance in deep water of up to 1 to 2.5 km water depth, is time intensive, error prone, and costly. Another option is to actively pull down the template and the related one of more mudmats. Pulling down the template can be done either one time or several times during the torqueing process of the helical pile. Torqueing herein means rotating the respective helical pile by applying an appropriate torque to the pile.

Referring generally to Figures 21 A to 21 D, the template 10 may be provided with a downforce system for providing additional downforce. The downforce system may comprise, for instance, one or more gears or pinions 760 for driving corresponding one or more toothed racks 762. The gears 760 may include, for instance, a cogwheel, gear wheel or worm wheel. The racks 762 may be longitudinal structures provided with teeth corresponding to the teeth of the respective gear. The gears 760 may be drivable by one or more motors. The motor or engine may be comparable to, or an add on to, the engine depicted in and described with respect to Figures 8A and 8B. The motors and gear wheels may be included in the connector block 36. The one or more racks 762 may be provided on one or more of the guide structures 342.

To allow the mudmat 24 to (partly) penetrate and engage the top surface of the seabed, the lower surface of the feet may be provided with one or more protrusions 770. The protrusions may have any shape and height suitable to penetrate and engage the seabed at a particular location. As the top soil of the sea bed may differ for respective locations, the shape of the protrusions may differ as well. In general, the protrusions extend downward with respect to the lower surface 24 of the respective foot 22. The protrusions may comprise, for instance, pins, needles, ridges, raised edges, or a combination thereof.

In use, the rotational drive included in the connector block 36 may rotate the respective helical pile 40. When the helical pile has entered the soil, the engine can also pull the template 10 into the ground, for instance by pulling on the helical pile without rotating the pile. Herein, the engine may drive the gears 760 driving the template downward with respect to the guide structures 342. As the helical pile 40 has, at least in part, entered the seabed, the helical pile will remain in position so that in essence the engine drives the lower surface 24 of the one or more feet 22 of the template into the seabed. Herein, the helical pile is not rotated (torqued) during pulling down of the mudmat 24.

Another option is to actively pull down the mudmat during the torqueing process, i.e. during rotation of the one or more helical piles 40. Herein, the template may have an active load control included in or on the motor system. The engine in the connector block 36 may pull the helical pile 40 upwards at a given force while the pile is rotated, generating an increased downward force while the helical pile is driven into the seabed. The required horizontal resistance of the mudmat increases when reaching larger penetration depth, and so does the upward capacity of the helical pile. Therefore, the pulling force applied by the gear and rack system may increase with increasing penetration depth of the respective helical pile 40. In this embodiment, the pulling load on the rack 762 and gears 760 increases the required torque to rotate the helical pile 40. Balancing toque and downforce may result in an optimum solution wherein the pulling load (by the downforce system, for instance comprised of the assembly of gears 760 and rack 762) is increased with increasing penetration depth over the first stage(s) of the installation of the helical pile 40. The pulling load may be decreased with increasing penetration depth or brought to zero at the later stages of the helical pile installation, i.e. when the helical pile 40 starts to reach its target depth.

In designing a suitable template for a particular project for the installation of offshore structures, the sediment of the seafloor is determined beforehand. The sediment however can vary over a wide range, with a significant difference between a lower and upper boundary. Any calculation with respect to the template however will have to be based on said lower boundary. The downforce system, exemplified by the assembly of gears 760 and racks 762 as described above, increases the range of suitable application of the template. For instance, by actively pulling the respective feet of the template into the soil, the assembly increases the lateral force each foot 22 can counteract (see 702 in Fig. 18). The assembly will allow the feet of the template to penetrate the seabed further (compared to penetration with only the weight of the template) thus increasing the lateral capacity the one or more feet can generate.

The downforce system, such as the assembly 760, 762, of the present disclosure can be activated at any time during the installation of the monopile or helical pile. For instance, additional downforce can be generated with the helical piles 40 inserted up to target depth. Herein, a certain torque is applied to the gears 760 (without rotation of the gears), applying a downforce to the template and feet via the respective rack 762. The latter downforce can be generated during a certain time, or continuously during the installation of the monopile 60. Herein, the engine or motor driving the gears 760 can be activated continuously even after the helical piles have reached target depth thus increasing the lateral capacity the one or more feet can generate.

Please note that the downforce system for linearly pulling the template into the seabed as exemplified with respect to Figures 21 A to 21 D can be applied to all other embodiments as described herein. The present disclosure relates to a template 10 having a linear guide structure 342 for guiding a connector block 36 for rotating a helical pile 40, as shown in Figure 22A. In a practical embodiment, the lower end of the one or more feet 22 may be provided with an opening 32 to allow a respective helical pile 40 to pass through.

Figure 22B schematically indicates a lateral force 780 acting on the template 10. Herein, the opening 32 may be relatively wide, to enable the helices 782, 784 of the helical pile 40 to pass. In use, due to the width of the opening 32 the lateral force 780 may be transferred to the connector block 36 via the guide structures 342. The latter may result in (slight) bending of the linear guides 342.

To avoid bending to the guide structures 342, the opening 32 may be provided with a gate structure 790. See Figure 22C for a schematic indication, and figures 23A to 24B for embodiments. The gate structure 790 may be able to move from an open position to a closed position and vice versa. In the open position, the structure 790 provides a relatively wide opening allowing the helices 782 of the pile 40 to pass through. In the closed position, the structure 790 provides a smaller opening. Herein, the structure 790 preferably engages the circumference of the pile 40. The latter allows to transfer to lateral force 780 via the one of more feet 22. This obviates the lateral force to pass via the guide structure 342 and the connector block 36, and avoids the guide structure to bend, as indicated in Fig. 22C.

When offsetting a torque on one helical pile to another pile, either with only one pile actively torqued or more than one pile actively torqued, the torque needs to be compensated. Please note that horizontal restraint on each mudmat is based on soil capacity of the top layers of the seabed. The torque creates a lateral load onto the structure providing the offset. The lateral load, when no horizonal support is available at the lower level, travels up via the supporting frame and then down through the pile towards the soil. The soil provides the eventual lateral capacity. As both the frame and the helical pile will flex, this may lead to misalignment between the frame and the helical pile. Also, it may generate a curvature in both (see Fig. 22B). The bending can be minimized by adding stiffness to both the frame and the helical pile, which would however increase costs. For the template, the added stiffness would be a onetime investment. For the helical piles, added stiffness would probably result in increased diameters to provide sufficient lateral or bending stiffness.

A knock on effect is that the required greater diameter adds to the required torque as the torque is a direct result of the area exposed to the soil and the arm towards the centre of the helical pile. As both the area and the arm have the radius incorporated, the required torque is quadratic to the radius ((r * (2 *Pi * r * L)) * friction factor) . Keeping the radius of the helical pile small may be important to keep the system financially attractive and efficient. Also, the installation time can be reduced, as greater torques typically require greater gearboxes, reducing the actual amount of revelations per minute.

The lower restraint reduces complexity of the drive-to-pile interface (such as the connector block 36), as the coupling between both (pile and drive system) would obviate the need to take up bending moments and/or the coupling can obviate the needs to allow for bending around the local x and y axis (i.e. the axes perpendicular to the longitudinal axis of the helical pile). As bending induced loading would be varying from full tension to full compression on each point on the circumference of the coupling over each revelation, this would release quite some strain on the drive system. Also, the gate structure ensures the pile is inserted relatively in a straight line (not necessarily being vertical), which makes the required torque more predictable.

When adding the horizontal restraints at the lower level, the lateral load imposed by one or more actively torqued helical piles would, at that location, be transferred to the soil from a far lower location resulting in far smaller bending moments. This would make sure that the lateral loads will not pass through the upper frame and the drive system to the helical pile and remove part of the complexity of the drive system for torqueing.

Referring to Figures 23A and 23B, in an embodiment, the gate structure 790 may comprise one or more arms 792. Each arm 792 may be able to pivot with respect to a hinge 794 between an open position (Fig. 23A) and a closed position (Fig. 23B). One end of the arm may be connected to the respective hinge 794. An opposite end of the arm may be provided with a bearing 796, for instance one or more rollers or ball bearing. The bearing 796 can engage the outer surface of the helical pile 40 while still allowing the helical pile to rotate. The gate device 790 may be provided with one or more actuators 798 to move the respective arms from the open position to the closed position and vice versa. The actuators 798 may be hydraulically activated.

Other embodiments of the gate structure are conceivable. For instance, the arms 792 may be hydraulically activated linear actuators, wherein the actuator and arm are integrated. The actuators 798 may be electromechanically activated. The template 10 may comprise multiple guide structures 30 for multiple respective helical piles 40. Each opening 32 of each helical pile guide structure 30 may be provided with a corresponding gate structure 790. See Figures 24A (open position) and 24B (closed position).

Clauses capturing the template and method of the disclosure may include:

A template (10) for introducing at least one helical pile (40) into the ground (1), in particular a seabed, wherein the template comprises:

- a base (20) comprising a foot (22), wherein the foot extends sidewardly away from a helical pile guiding device (30) in at least one sideward direction and comprises a lower surface (24), wherein the template is configured to rest on a seabed via the lower surface of the foot,

- the at least one helical pile guiding device, wherein the helical pile guiding device is configured to guide a helical pile into the ground from an initial pile position (42), the helical pile guiding device comprising: o a lower passage (32), located at a lower end (420) of the initial pile position, and being configured to allow a helical pile to pass through it, o at least one upwardly oriented guiding member (34) connected to the base and extending upwardly from the base, o a pile connector (36) connected to the at least one upwardly oriented guiding member, wherein the pile connector is configured to be connected to a helical pile, wherein the pile connector guides an upper end (422) of a helical pile during the helical pile’s downward movement, one or more drives (50) for rotating a helical pile, wherein the rotation drives a helical pile into the seabed, wherein an interaction of the lower surface with the seabed counteracts a torque applied to the helical pile when screwing the pile into the seabed.

A method for introducing at least one helical pile (40) into the ground using a template (10), wherein the template comprises:

- a base (20) comprising a foot (22), wherein the foot extends laterally away from a helical pile guiding device in at least one lateral direction and comprises a lower surface (24),

- at least one helical pile guiding device (30), wherein the guide structure is configured to guide a helical pile into the ground from an initial pile position (42), the guide structure comprising: o a lower passage (32), located at a lower end of the initial pile position, and being configured to accommodate a helical pile, o at least one upwardly oriented guiding member (34), o a pile connector (36) connected to the at least one upwardly oriented guiding member, wherein the pile connector is configured to be connected to a helical pile, wherein the pile connector guides an upper end (422) of a helical pile during the helical pile’s downward movement,

- one or more drives (50) for rotating a helical pile, wherein the method comprises the steps: a) lowering the template on the seabed, b) actuating the one or more drives, screwing in the at least one helical pile into the seabed, c) disconnecting the template from the at least one helical pile, d) retrieving the template from the seabed, wherein the at least one helical pile remains screwed into the seabed during and after the retrieval of the template and wherein an interaction of the lower surface with the seabed provides a counteracting force that counteracts a torque applied to the helical pile when screwing the pile into the seabed.

Any of the appended claims may refer to or depend on the clauses as included herein above.

The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising i.e., open language, not excluding other elements or steps.

Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention. It will be recognized that a specific embodiment as claimed may not achieve all of the stated objects.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

White lines between text paragraphs in the text above indicate that the technical features presented in the paragraph may be considered independent from technical features discussed in a preceding paragraph or in a subsequent paragraph. The present disclosure is not limited to separate embodiments as described above, wherein many modifications are conceivable within the scope of the appended claims. Features of respective embodiments may for instance be combined.

Claims

- 39 -

CLAIMS A template (10) for introducing at least one helical pile (40) into the ground (1), in particular a seabed, wherein the template comprises:

- a base (20) comprising at least one foot (22), wherein the at least one foot extends sidewardly from a corresponding at least one helical pile guiding device (30) in at least one sideward direction and comprises a lower surface (24) configured to engage the seabed,

- wherein the at least one helical pile guiding device (30) is configured to guide a helical pile into the ground from an initial pile position (42), the at least one helical pile guiding device comprising: o a lower passage (32), located at a lower end (420) of the pile guiding device (30) and being configured to allow a helical pile to pass through it, o at least one upwardly oriented guiding member (34) connected to the base and extending upwardly from the base, o a pile connector (36) connected to the at least one upwardly oriented guiding member (34), wherein the pile connector is configured to be connected to a helical pile, wherein the pile connector guides an upper end (422) of a helical pile during the helical pile’s downward movement, one or more drives (50) for rotating the at least one helical pile and driving the helical pile into the seabed, wherein the lower surface of the at least one foot is adapted to interact with the seabed to counteract a torque applied to the at least one helical pile when rotating the pile and driving the pile into the seabed. Template according to the previous claim, wherein the pile connector is moveable along the at least one upwardly oriented guiding member (34), and wherein the pile connector is moveable between an upper position (362) and a lower position (364). Template according to any of the previous claims, wherein the pile connector defines a guide space (38) with an inner diameter (382) configured to allow a helical pile to pass through the guide space. Template according to any of the previous claims, wherein the lower passage extends through the base (20). - 40 -

5. Template according to any of the previous claims, wherein the one or more drives are integrated in the at least one helical pile guiding device (30), in particular in the pile connector (36) of the at least one helical pile guiding device.

6. Template according to any of the previous claims, wherein the base (20) does not comprise an anchoring device configured to anchor the base to the seabed

7. Template according to any of the previous claims, wherein the template (10) comprises three helical pile guiding devices (30A, 30B, 30C).

8. Template according to any of the previous claims, wherein when seen in top view the at least one foot has one of a triangular shape, an elliptical shape, a rectangular shape, or other polygon shape, each shape comprising a geometric centre (26).

9. Template according to any of the previous claims, wherein the base (20) comprises at least one torque member (28) extending away from a geometric centre (26) when seen in top view, in particular, three torque members, wherein the at least one torque member is configured to interact with the seabed to create a counter-torque when a helical pile is driven into the seabed, and wherein the at least one torque member comprises a lower surface configured to rest on the seabed.

10. Template according to any of the previous claims, wherein the base (20) comprises at least three torque members (28), wherein at least one torque member is at least twice as long as at least one other torque member.

11. Template according to any of the previous claims, wherein the at least one helical pile guiding device (30) is located at a distance from the geometric centre of the base (20) and wherein the at least one helical pile guiding device (30) and the at least one torque member (28) are located on opposite sides of the geometric centre of the base (20).

12. Template according to any of the previous claims, comprising multiple helical pile guiding devices (30, 30A, 30B, 30C) located at a distance (204) from the geometric centre of the base (20).

13. Template according to any of the previous claims, wherein at least one helical pile guiding device is located at each vertex of the polygon shape of the foot (22). - 41 - Template according to any of the previous claims, wherein each helical pile guiding device (30) comprises multiple upwardly oriented guiding members (34). Template according to any of the previous claims, wherein each upwardly oriented guiding member (34) is a guiding rod (342) or guiding rail. Template according to any of the previous claims, wherein multiple guiding members (34) are positioned around the lower passage (32) when seen in top view and wherein the pile connector (36) is connected to each upwardly oriented guiding member. Template according to any of the previous claims, wherein the pile connector is connected to the at least one upwardly oriented guiding member, the connection allowing a translation but not a rotation of the pile connector, wherein the pile connector is maintained in the same orientation, in particular horizontal, by the at least one guiding member during its downward movement. Template according to any of the previous claims, wherein the pile connector comprises a drive coupler (52), the drive coupler being configured to couple the drive to the helical pile, wherein the drive coupler comprises drive projections (522) that project into the guide space and wherein the drive is configured to rotate the drive projections about a central axis (7) of the guide space, and wherein helical pile comprises a pile coupling (44) comprising pile projections (442) that project outwards, wherein the drive projections engage the pile projections and the rotation of the drive projections rotates the helical pile. Template according to any of the previous claims, wherein the pile connector comprises a connector coupling (366) configured to be connected to the helical pile, in particular to a pile coupling on the pile, wherein the connector coupling comprises coupling projections (368) that project outwards and wherein the drive projections engage the coupling projections and the rotation of the drive projections rotates the connector coupling, and wherein the rotation of the connector coupling rotates the helical pile. Template according to any of the previous claims, wherein the connector coupling is configured to be connected to the upper end of the helical pile, in particular by gripping force or by form fit. 21. Template according to any of the previous claims, wherein the drive is incorporated in the pile connector (36) and is adapted to move downward with the pile during the driving of the pile into the seabed.

22. Template according to any of the previous claims, wherein the connector coupling is detachable from the upper end of the helical pile and the lower passage is larger than the upper end of the helical pile.

23. Template according to any of the previous claims, the template comprising at least two helical pile guiding devices, wherein at least one helical pile guiding device is oriented at a first angle (3) of less than 80 degrees with respect to the lower surface (24) of the foot (22) and wherein at least one helical pile guiding device is oriented at a second angle (5) of 85-95 degrees with respect to the lower surface (24) of the foot, for instance at least two helical pile guiding devices being oriented at an angle of 85-95 degrees with respect to the lower surface of the foot.

24. Template according to any of the previous claims, wherein at least one first helical pile guiding device is at least 50% larger than another helical pile guiding device.

25. Template according to any of the previous claims, wherein the template is configured for guiding at least one foundation pile (60) during the driving thereof into the seabed, the template comprising at least one foundation pile guide (62) connected to the base (20) and configured to accommodate a foundation pile (60), defining an opening (622) through which the foundation pile can be inserted into the seabed.

26. The template of claim 25, comprising at least one helical pile (40) connected to the at least one helical pile guiding device (30), wherein the at least one helical pile (40) is configured to keep the foundation pile guide (62) in a target position and in a target orientation and to resist lateral forces acting on a foundation pile (60) accommodated by the at least one foundation pile guide (62).

27. Template according to claim 25, wherein the at least one foundation pile guide (62) and the at least one helical pile guiding device (30) are located at a distance (64) from each other.

28. Template according to claims 25 or 26, wherein the template comprises a same number of foundation pile guides (62) as helical pile guiding devices (30). 29. Template according to any of claim 25 to 28, comprising at least twice as many helical pile guiding devices as foundation piling guides.

30. Template according to any of the previous claims, wherein each of a first number of helical piles comprise a clockwise pitch and each of a second number of helical piles comprise a counter-clockwise pitch, or wherein each helical pile comprises a clockwise pitch or counter-clockwise pitch.

31. Template according to claim 30, wherein the first number and the second number are the same.

32. Template according to any of claims 1-28, wherein each helical pile comprises a clockwise pitch or each helical pile comprises a counter-clockwise pitch.

33. Template according to any of claims 25 to 28, wherein each foundation pile guide (62A, 62B, 62C) comprises a separate base (66) which extends around the opening (622), the separate base comprising a flange or a rim.

34. Template according to any of claims 25 to 28 or claim 33, wherein each foundation pile guide comprises an upwardly facing guide plate (68) which tapers outwardly, in particular conically outward, and is configured to guide the foundation pile (60) into the opening (622).

35. Template according to any of claims 25 to 34, comprising at least three helical pile guide devices (30A, 30B, 30C) enclosing the foundation pile guide (62).

36. Template according to any of the previous claims, wherein one or more of the at least one helical pile guiding device (30) is provided with a downforce assembly.

37. Template according to claim 36, the downforce assembly comprising: at least one gear (760) provided in the pile connector (36); at least one rack (762) provided on the guidign member (34); and at least one motor for rotating the gear with respect to the rack.

38. Assembly of a template according to any of the previous claims and at least one helical pile (40) in the initial helical pile position. - 44 -

39. Assembly according to claim 34, wherein an upper end of the at least one helical pile comprises a pile coupling wherein the pile coupling is coupled to the helical pile guiding device via the pile connector, in particular via the connector coupling.

40. Assembly according to claim 34 or 35, wherein a first lower end of at least one helical pile extends below the base and through the lower passage.

41. Assembly according to any of claims 34 to 36, wherein the assembly comprises at least three helical piles.

42. Assembly according to any of claims 35 to 38, wherein the template comprises at least three helical pile guiding devices (30, 30A, 30B, 30C) and the template has a triangular shape, wherein each helical pile guiding device is located near a vertex of the triangular shape.

43. Assembly according to any of claims 35 to 39, comprising at least one helical pile (40A) having a first end (402) and a second end (404) opposite the first end, and a flexible member (406) connected to the second end (404).

44. The assembly of claim 40, wherein the flexible member comprises one or more of a cable, a chain, and a wire.

45. Method for introducing at least one pile into the seabed using a template (10), wherein the template comprises:

- a base (20) comprising at least one foot (22) extending laterally away from at least one helical pile guiding device (30) and comprising a lower surface (24) for engaging the seabed (1), wherein the at least one helical pile guiding device (30) is configured to guide a helical pile into the ground from an initial pile position (42), the helical pile guiding device comprising: o a lower passage (32), located at a lower end of the helical pile guiding device, and being configured to accommodate a helical pile, o at least one upwardly oriented guiding member (34), o a pile connector (36) connected to the at least one upwardly oriented guiding member (34), wherein the pile connector is configured to be connected to a helical pile and to guide an upper end (422) of the helical pile during downward movement thereof,

- one or more drives (50) for rotating the helical pile, - 45 - wherein the method comprises the steps: e) arranging the template (10) on the seabed (1), f) actuating the one or more drives (50) for rotating the at least one helical pile and driving the helical pile into the seabed, wherein an interaction of the lower surface (24) of the at least one foot (22) with the seabed (1) provides a force counteracting a torque applied to the at least one helical pile when screwing the pile into the seabed (1).

46. The method of claim 43, comprising the steps of:

- disconnecting the template (10) from the at least one helical pile (40), retrieving the template (10) from the seabed (1), wherein the at least one helical pile (40) remains screwed into the seabed during and after the retrieval of the template.

47. The method according to claim 43 or 44, wherein the at least one helical pile (40) is placed in the initial pile position prior to step a) and/or is connected to the guiding device prior to step a).

48. Method according to any of claims 43 to 45, wherein the lower surface comes into contact with the seabed during step a) and the contact offers a counter torque to the drives during step b).

49. Method according to any of the previous method claims, wherein multiple helical piles are alternately rotated.

50. Method according to the previous claim, wherein a first helical pile is rotated while a torque is applied to at least one other helical pile without rotating the at least one other helical pile.

51. Method according to any of claims 43-46, wherein multiple helical piles are simultaneously rotated.

52. The method of claim 49, wherein the torque drives of respective helical piles are operated simultaneously to substantially or fully counter each other’s torque, more specifically more than 50%. - 46 -

53. Method according to any of the previous method claims, wherein during step d) the template is moved away from the seabed and the lower passage is moved over an upper end of the helical pile.

54. Method according to any of the previous method claims, wherein the template comprises at least a first helical pile guiding device (30A) being oriented at an angle of less than 80 degrees with respect to the lower surface (24) of the at least one foot (22) and at least a second helical pile guiding device (30B, 30C) being oriented at an angle of 85-95 degrees with respect to the lower surface (24) of the at least one foot (22), wherein during step b) a second helical pile (40A) corresponding to the second helical pile guiding device is driven into the seabed (1) prior to the driving of a first helical pile (40B) corresponding to the first helical pile guiding device, wherein the second helical pile counteracts a moment about a horizontal axis created during the driving of the first helical pile.

55. The method of claim 43,

- wherein the template comprises at least one foundation pile guide (62) connected to the base (20) and configured to accommodate a foundation pile (60), the guide (62) defining an opening (622) through which the foundation pile can be inserted into the seabed, the method comprising the steps of: while the at least one helical pile (40) is in the seabed, driving at least one foundation pile (60) into the seabed via the opening (622) of the at least one foundation pile guide (62); retrieving the at least one helical pile (40); and retrieving the template from the seabed (1).

56. The method of claim 52, wherein the template comprises at least three helical pile guiding devices (30A, 30B, 30C), the method comprising the step of driving at least three helical piles (40A, 40B, 40C) into the seabed using the at least three helical pile guiding devices.

57. The method of claim 53, comprising the step of keeping the at least one foundation pile guide (62) in a target position and in a target orientation by adjusting the location of one of the pile connectors (36) with respect to the helical pile (40A) of the respective helical pile guiding device (30A). - 47 -

58. The method according to claim 53 or 54, wherein, after getting the helical piles to a penetration depth, one or more helical piles are displaced relatively to the template without rotating the respective helical piles to bring the foundation pile guide (62) within tolerance to the vertical, typically between 1 degrees, more specifically within 0.5 of the vertical.

59. The method of one of claims 52 to 54, wherein the at least one foundation pile guide (62) and the at least one helical pile guiding device (30) are located at a distance (64) from each other.

60. The method of one of claims 52 to 55, wherein the template comprises a same number of foundation pile guides (62) as helical pile guiding devices (30).

61. Method according to any of claims 43 to 56,

- wherein at least one helical pile comprises a first end (402), a second end (404), and a flexible member (406) connected to the second end,

- the method comprising the step of driving the at least one helical pile and a part of the flexible member into the seabed, wherein the second end (404) is at a distance below the seabed and the flexible member (406) extends above the seabed.

62. Method according to the preceding claim, wherein the drive is actuated until the second end (404) of the helical pile is located under the seabed, in particular more than 4 meters under the seabed, more in particular more than 6 under the seabed.

63. Method according to any of claims 57 or 58, wherein the helical pile is driven to a predetermined depth and the flexible member is released after a predetermined time period by releasing the release mechanism.

64. The method of claim 59, wherein the second end (404) comprises coupling means comprising a pad eye, wherein the flexible member passes through the pad eye, the method comprising the step of after a predetermined time period moving a first end of the flexible member away from the recess, pulling a second end through the recess and releasing the flexible member from the coupling means.

65. The method according to any of the claims 45 to 64, wherein one or more of the at least one helical pile guiding device (30) is provided with a downforce assembly.

66. The method according to claim 65, the downforce assembly comprising: - 48 - at least one gear (760) provided in the pile connector (36); at least one rack (762) provided on the guiding member (34); and at least one motor for rotating the gear with respect to the rack, the method comprising the step of activating the at least one motor to apply a torque to the at least one gear. A method of introducing a monopile into the seabed using a template, wherein the template comprises:

- a base (20) comprising at least one foot (22) for engaging the seabed (1), at least one helical pile guide structure (30) and at least one foundation pile guide structure (62),

- wherein the foot extends sidewardly away from foundation pile guide structure (62) and/or the helical pile guide structure (30) in at least one sideward direction and comprises a lower surface (24),

- at least two pile guiding devices, wherein the helical pile guide structure is configured to guide a helical pile into or out of the ground from an initial pile position, the guide structure comprising: o a lower passage, located at a lower end of the initial pile position, and being configured to accommodate a helical pile, o at least one upwardly oriented guiding member, o a pile connector connected to the at least one upwardly oriented guiding member, wherein the pile connector is configured to be connected to a helical pile, wherein the pile connector guides an upper end of a helical pile during the helical pile’s downward movement, o Two or more drives for rotating a helical pile,

- one monopile guiding device, wherein the guide structure is configured to guide a monopile into the ground from an initial pile position, the guide structure comprising: o a lower passage, located at a lower end of the initial pile position, and being configured to accommodate a monopile, o at least one upwardly oriented guiding member, wherein the method comprises the steps: a) lowering the template on the seabed, b) actuating the one or more drives, screwing in the at least two helical piles into the seabed, c) positioning a monopile into the guiding member d) installing the monopile into the seabed - 49 - e) actuating the one or more drives, screwing in the at least two helical piles out of the seabed, f) retrieving the template from the seabed, wherein the monopile remains in the seabed during and after the retrieval of the template. The method of claim 63, wherein the base comprises at least two torque members (28) that extend away from a geometric centre when seen in top view, in particular, three torque members, wherein the at least two torque members are configured to interact with the seabed to create stability and/or uplift capacity and/or add stiffness when the monopile is driven into the seabed and wherein the at least two torque members comprises a lower surface configured to rest on the seabed.