WO2013140421A1

WO2013140421A1 - A seabed anchoring device

Info

Publication number: WO2013140421A1
Application number: PCT/IS2013/050002
Authority: WO
Inventors: Hilmar ERLINGSSON
Original assignee: Hafbor Ehf.
Priority date: 2012-03-23
Filing date: 2013-03-25
Publication date: 2013-09-26

Abstract

The present invention relates to a device and system for embedding anchor into the seabed, and in particular, but not limited, to embedding anchor for buoy for shellfish growth lines. According to the first aspect of the present invention there is provided a seabed anchor embedding device, comprising a retrievable base frame assembly, adapted to be mounted on the seabed, an anchor, means for lowering said base frame assembly from a vessel through a body of water into a mounting position at the seabed and for retrieving said frame assembly after said anchor has been embedded.

Description

A SEABED ANCHORING DEVICE

FILED OF THE INVENTION

The present invention relates to a device and system for embedding anchor into the seabed, and in particular, but not limited, to embedding anchor for buoy for shellfish growth lines.

BACKGROUND OF THE INVENTION

The technique of securing pools or anchors within the earth to provide structural foundation is well known . Likewise is the use of manmade anchor structures such as stones or large concrete blocks well known in subsea- environment.

Subsea anchor have been widely used for boats and other objects, both floating structures as well as structures arranged on or along the seabed. In many offshore environments the ocean or sea floor is typically formed with a top layer of relatively soft material, such as mud, slit or sand or the like, overlaying the substantial consolidated material and bedrock.

Marker buoys have been deployed to mark location in the sea. Some merely float in the sea to mark a location but have no means to be secured to a particular underwater location to fixedly mark such location . Other has been secured to the seabed by use of large stones or concrete sinking block or other kind of seabed anchoring . In recent years there has been growing activity in the development of different kind of fish-farming, in particular devices and structures which operate in offshore environment, for example buoy lines for shellfish growth, floating cages or nets for salmon and other similar farmed fish species. Such devices typically require to be anchored to the seabed, and thus require some form of foundation support. This kind of support has typically been provided by gravity anchors, which have involved locating a large number of big blocks of concrete or large stones of several tons on the seabed. This has presented not only a significant handling issues, but also significant environmental issue where even hundreds or even thousands of such blocks lying on the seabed. Just the operation of retrieving the blocks back can be complicated and hazardous.

The nature of offshore fish-farming devices requires anchoring where extreme weather or current flow conditions are not uncommon. Such conditions, for example strong waves, tidal and current activity may render use of gravity anchors non-usable.

A number of non-gravity anchoring devices for boats and other offshore floating object have been provided. US 3,187,705 describe a boat anchor having an internally mounted shaft to penetrate the ocean floor. US

4,960,064, US 5,613,458 and 6,606,829 disclose a spike like anchor. US 3,841,105, US 3,479,830 , US 4,389,034, US 4,492,493, US 5.730,552 as well as US 6,066,015 disclose the use of a screw-type element (anchor) that are embedded into the earth surface under-water.

Existing subsea screw-anchors and anchoring devices such as shown in US 6.066,015 have shown several disadvantages. In particular, but not limited to, has it been difficult to screw or drill the anchor into the seabed (if the desired position on the seabed is dense or if it is in some way difficult to screw the anchor into the seabed). First of all is the size and weight of the screwing/drilling device problematic. In order to secure the device to the seabed the device must have sufficient weight, whether that is provide by the weight of the structure self or by additional gravity type weight accompanied to the device. However the structure cannot be too heavy so that it will be required to use specially designed lifting cranes arranged on a large floating- barge. It is necessary for the environment such as fish-farming that it will be possible to use smaller fishing vessel or boats having only simple and light- lifting cranes. Use of special lifting cranes or large ships than traditionally used on daily basis in the fish farming, will not be feasible. If the device does not have sufficient weight it will be difficult to engage the drilling the anchor into the seabed. Either, it may be difficult to engage the anchor into contact with the seabed as there is not sufficient gravity pressure from the structure, or as the anchor engage into initial contact with the seabed as it rotates the whole structure would rotate there with.

SUMMARY OF THE INVENTION

The present invention solves the above mentioned problems by providing a device for embedding an anchor into the seabed, where the anchor is a screw anchor. The problems listed above are solved by placing the anchor in a base frame assembly where the base frame assembly is lowered to the seabed to a position where the anchor is to be embedded. In order to be able to screw the anchor a sufficient distance into the seabed, the base frame assembly needs to be secured to the seabed. This problem is solved by providing seabed penetrable securing members, which are attached to the base frame assembly. As there are pluralities of such seabed penetrable securing members attached to the frame assembly, the base frame assembly is both stabilized and secured to the seabed. By securing the base frame assembly to the seabed, it is possible to remotely drill/screw the anchor further into the seabed and to release the anchor from the base frame assembly. After the anchor has been released from the base frame assembly, the base frame assembly it self can be released from the seabed by reverse rotation of the seabed penetrable securing members. If the base frame assembly is not secured to the seabed, the seabed around the anchor will be partially ruffled up instead of only screwing the anchor in to the seabed. By securing the base frame assembly to the seabed it prevents the seabed around the anchor to be ruffled up instead of securing the anchor in it and the precision of embedding an anchor into the seabed is increased as the frame is stabilised on the seabed. Such an anchor embedding device needs to be remotely controlled and therefore it is also a part of the solution to be able to remotely release the anchor from the frame and to release the frame from the seabed after the anchor has been embedded to the seabed. According to the first aspect of the present invention there is provided a seabed anchor embedding device, comprising a retrievable base frame assembly, adapted to be mounted on the seabed, an anchor and means for lowering said base frame assembly to a mounting position at the seabed and for retrieving said frame assembly after said anchor has been embedded. The base frame assembly further comprises a horizontal seabed mounting member facing the seabed in a working position, a vertical upright guiding structure arranged above and on the seabed mounting member, said seabed mounting member having a number of seabed penetrable securing members and an anchor drilling device, vertically guided on said guiding structure. The anchor is releasable connected to said anchor drilling device. The seabed anchor embedding device is characterized in that, each of the securing members is formed as retractable screw-drilling device for securing said base frame assembly in a position while embedding said anchor into the seabed and releasing said anchor from said anchor embedding device.

The device may further comprise an anchor embedding device wherein said seabed penetrable securing members being two, three or more. Additionally the device may comprise a two way motor drive. The seabed penetrable securing members, also referred to as retractable screw-drilling device are remotely controlled when they are screwed into or retracted from the seabed.

BRIEF DESCRIPTION OF THE DRAWING

For further understanding of the device and objectives of the present invention, reference should be made to the following description taking into consideration the accompanying figure drawings in which parts are given like reference number and, wherein; Figure 1 illustrate a side view of a seabed anchor device of the present invention lowered from a vessel to the seabed,

Figure 2 illustrates a top view of a horizontal support member of the anchor device, Figure 3 show side view of the lower part of the anchoring device where the screw anchor is being embedded,

Figure 4 illustrate a side view of the connection between the screw-anchor and the anchor drilling device and

Figure 5 illustrate an anchor with buoy line or the like, embedded in the ocean floor. Figure 6 illustrate a top view of a horizontal support member of the anchor device in a slightly different way form fig 2.

Figure 7 illustrate the anchor embedding device of figure 1 in a slightly different view that shown in figure 3.

Figure 8 illustrate somewhat in more detail what figure 4 shows.

Figure 9 illustrate the screw anchor in figure 5 in a slightly different fashion.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is first made to figure 1 of the drawings in which the anchor embedding device is shown. The device 1 is deployed into the body of water with the assistance of a simple lifting crane 21, of a small floating vessel 2. The size ration between the vessel 2 and the device 1 on the figure are out of proportion and having only illustrative purpose.

The device is lowered via cable 22, or like from the vessel 2, down to the ocean floor 3. The device comprise an horizontal seabed support member 4, and a vertical upright guiding structure 5, arranged on and above the seabed support member 4. Said guiding structure 5, include a guiding rail or like 23, for allowing up and downward (vertical) movement of an anchor drilling device 6 arranged thereon. Releasable connected to the drilling device is connected a screw anchor 7. The seabed support member 4, include a number of securing members in the form of retractable screw-drilling device 9. In operation, when the device is lowered from the vessel 2, down to the seabed 3, the stabilizing screw-drill device 9, engage to the seabed. As being motor driven 24, either electrical, hydraulic or pneumatic, the screw drill 9, dig or screw there into and at the same time pull the support member 4, down to the seabed so it as well as the frame assembly 1, as a whole sits securely fasten to the seabed. As the assembly 1, is securely fasten to the seabed 3, the drilling device 6, is lowered along the guiding rail 23, until the tip 25, of the screw anchor 7 touch the seabed 3. By rotation of the anchor 7, with the anchor drilling device 6, the anchor starts to screw itself into the seabed and simultaneously pull the drilling device downwards. When the anchor 7 has been embedded it is released from the drill and the stabilizing screw-drill device 9, rotated in the reverse direction to release the assembly 1 from the seabed so it can be lifted again, a new screw anchor attached and the device moved to a new location for anchor embedment.

Figure 2, illustrates a top view of the horizontal seabed support member 4 of the anchor device. A triangular frame structure 4, is shown with a drill motor drive 24, on each corner of the frame. Figure 3, illustrate the anchor embedding device of figure 1, where in the screw drill 9, and the screw anchor 7, have been embedded into the seabed. In addition a fastening means 12, at the upper end of the screw anchor for a buoy line 11, is shown. It is further shown that the drilling device 6, have been moved downward along the guiding rail 23, of the guiding structure 5, as the screw-anchor 7, is embedded further into the ground.

Figure 4, illustrate one possible way of connecting the anchor drilling device 6, to the screw anchor 7. The upper end 31, of the screw anchor 7, is arranged with engagement means, such as aperture 32, that are able to engage with a screw locking means 34, of the drilling device. When a screw anchor 7, is connected to the drilling device 6, its upper end 31, enters a receiving section of the drilling device where a pair of locking means 34, such as retractable pin bolts enters the aperture of the upper end of the anchor. Such locking means can be manually adjustable or alternatively having a electrical, pneumatic or hydraulic driven locking mechanism. Figure 5 illustrate an screw anchor 7, which has been embedded into the seabed 3, having a buoy 11, attach to the anchor via a line connector 36. Figure 6 illustrate what is already shown in figure 2 in a slightly different form.

Figure 7 illustrate the anchor embedding device of figure 1, where in the screw drill 9, and the screw anchor 7, have been embedded into the seabed in a slightly different view that shown in figure 3.

Figure 8 illustrate somewhat in more detail what figure 4 shows. In particular the connection between the upper end 36 of the screw anchor 7 and the drilling device 6. One example of a releasable locking mechanism 33 is shown comprising a pair motor driven 39 pin locks 40 which engage into contact with aperture 37 at the upper end 36 of the screw anchor.

Figure 9 illustrate the screw anchor in figure 5 in a slightly different fashion. It should be understood that the embodiments described above are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention.

Claims

1. A seabed anchor embedding device, comprising : · a retrievable base frame assembly (1), adapted to be mounted on the seabed,

• an anchor (7), · means for lowering said base frame assembly to a mounting position at the seabed (3) and for retrieving said frame assembly (1) after said anchor (7) has been embedded, said base frame assembly (1) comprising;

• a horizontal seabed mounting member (4) facing the seabed in a working position,

• a vertical upright guiding structure (5) arranged above and on the seabed mounting member (4), said seabed mounting member (4) having a number of seabed penetrable securing members (9),

• an anchor drilling device (6), vertically guided on said guiding

structure (5),

• said (screw) anchor (7) being releasable connected to said anchor drilling device (6), characterized in that, each of the securing members is formed as retractable screw-drilling device (9) for securing said base frame assembly in a position while embedding said anchor (7) into the seabed (3) and releasing said anchor from said anchor embedding device.

2. An anchor embedding device according to claim 1, wherein said seabed penetrable securing members being two, three or more.

3. An anchor embedding device according to claim 1 or 2, wherein said drilling device 9, comprise a two way motor drive 24.