Fillable Anchor

Abstract

A tillable anchor has a number of planar sides, typically four, attached to a base and to one another, forming an enclosed structure with a cavity therein. Attachment points for a deployment line and for mooring lines are provided. After the empty anchor is deployed to the seafloor or other water bottom, an inlet and an outlet permit placement of a flowable weight material into the cavity. The anchor may have an extended skirt around the base to enhance holding capability.

Description

BACKGROUND—FIELD OF THE INVENTION

Anchors are used to moor floating vessels to a water bottom, such as the seafloor. A number of different types of anchors have been developed, from simple versions which rely mostly on their weight to provide the mooring force, to other anchors that embed into the seafloor in response to mooring line pull. Embedment provides additional mooring force.

Although increased anchor weight generally provides increased mooring force, as is well known the increased weight gives rise to issues in handling the anchor on the surface.

SUMMARY OF THE INVENTION

The fillable anchor embodying the principles of the present invention, in a preferred embodiment, comprises a framework covered with sheet or planar material, for example sheet metal, forming a cavity within. The framework may also be of metal. The anchor may be placed on the seafloor, then the cavity filled with a desired amount of flowable weighted material to create a suitably weighted anchor. Various types of flowable weighted material may be used to fill the cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of the fillable anchor of the present invention.

FIG. 2 is a perspective view of the fillable anchor of FIG. 1.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT(S)

While various anchors can embody the principles of the present invention, with reference to the drawings some of the presently preferred embodiments can be described.

With reference to FIGS. 1 and 2, fillable anchor, referred to at times as anchor 10, comprises, generally, a hollow form which may comprise a framework, for example of metal, covered by planar material such as sheet metal. While anchor 10 may take various shapes, FIGS. 1 and 2 show possible shapes. Anchor 10 comprises a base 12 and a plurality, namely three or more, planar sides 14. Sides 14 are connected to base 12 and to one another, forming an enclosed, hollow structure. Preferably, anchor 10 comprises four sides 14, forming (when viewed from a side, as in FIG. 1) a generally truncated pyramidal shape with rectangular or square base 12, with sides 14 tapering up to an upper end, which may form a flat surface 16. Flat surface 16 has a side length denoted as B in the figures.

It is understood that anchor 10 is hollow, and comprises a cavity 18 therein. Openings may be provided in one or more of the sides 14. Base 12 of anchor 10 may comprise a relatively sharp edge 13 to ease anchor 10 digging into a seafloor when pulled. A skirt or extension 40 may be provided around at least part of the edge of base 12 to provide increased holding force.

An attachment point 60 may be provided on flat surface 16, preferably substantially centered thereon, for attachment of a deployment line. It is understood that attachment point 60 may also be used to attach a mooring line.

One or more of sides 14 may comprise openings 20, to permit water entry into/flow out of cavity 18. One or more mooring lines 30, as shown in FIG. 1, may be connected to anchor 10. Mooring lines 30 may be connected at the central top, as in FIG. 1; or alternatively (or in addition) on one or more sides, also shown in FIG. 1. In particular, attachment points 66 may be provided at openings 20. Referring to FIG. 1, one possible arrangement for attachment points 66 comprises a plate 64 positioned over an opening 20, preferably on the inside of anchor 10, and bolted or otherwise fixed in place. A ring element, for example a padeye, provides an attachment point 66 for a mooring line 30.

FIG. 1 is a side view of one embodiment of anchor 10. While anchor 10 may be made any desired size, and in a variety of shapes, the following proportional dimensions are believed to yield an efficient design: referring to FIG. 1, with dimension A being the width of base 12 of anchor 10, dimension B (the side length of flat surface 16) being approximately 20% to 30% of dimension A, for example 26% of dimension A; and dimension C (being the height of anchor 10 from base 12 to flat surface 16) being approximately 30% to 40% of dimension A, for example 38% of dimension A. It is understood that these relative dimensions can be adjusted to suit particular settings.

As noted above, a skirt 40 (shown as a dotted line in FIG. 1, extending beyond the edges of base 12; it is understood that only a portion of an exemplary skirt 40 is shown, as skirt 40 would typically extend around the entirety of the perimeter of base 12) may be provided around the edges of the base 12 of anchor 10, to enhance holding force.

Cavity 18 may be filled with suitable weight material, preferably after anchor 10 is in place on the seafloor. Anchor 10, in its unfilled configuration, is relatively light and can be easily handled at the surface. Anchor 10 may be lowered to the seafloor via mooring line 30 or via one or more installation lines, for example attached to attachment point 60. Preferably, two or more inlet/outlet members 50 are provided, which provide a passage for fluid (including but not limited to flowable weighted materials, and water, for example seawater) to flow into and/or out of cavity 18. It is understood that inlet/outlet members may be positioned in any desired location on anchor 10.

In a presently preferred embodiment, once in place on the seafloor, anchor 10 is filled with a flowable weighted material, which may be a heavy liquid, for example a heavy “mud” similar to that used in the oil and gas drilling industry, which typically (but not exclusively) use barite as the weighting material. Using such flowable weighted material as an example, such liquid weighting material (typically a mixture of a water base fluid, barite, and gelling material) may be pumped down to anchor 10 and into cavity 18. A hose (not shown) is connected to one of inlet/outlet inlet members 50 to pump the mud into cavity 18, while another of inlet/outlet members 50 forms a discharge opening to permit seawater within cavity 18 to be displaced by the weighted liquid. It is understood that the positions of inlet/outlets 50, as shown in FIG. 1, are by way of example only, and may be in other positions on anchor 10. Inlet/outlets 50 may be provided with pressure regulating elements 52, shown in schematical form, to control flow into and out of cavity 18.

Stiffening members 200 may be provided, preferably on the outer surface of sides 14.

It is understood that any form of heavy, pumpable liquid or slurry may be placed inside cavity 18, including the barite-based fluid previously mentioned, or slurries containing other weighting materials such as hematite. In addition, other flowable weighted materials could be used, such as slurries containing solids of suitable size/density. In certain applications, heavy brines (with densities exceeding seawater, for example in the 16 pound per gallon to 18+ pound per gallon) range could be used to fill cavity 18 of anchor 10.

Mooring lines 30 may be attached at any location on anchor 10, to yield the desired mooring force and direction of pull.

Materials and Fabrication

While various materials could be used to fabricate anchor 10, exemplary materials include steel or other metals to form a framework if desired, with sheet metal or similar material to form planar sides 14. It is understood that other high strength non-metallic materials could be used if desired. In some embodiments, sides 14 and base 12 may be joined to form anchor 10 without an additional framework. Methods of fabrication known in the relevant art could be used, including but not limited to welding, bolting, riveting, or other suitable methods.

CONCLUSION

While the preceding description contains many specificities, it is to be understood that same are presented only to describe some of the presently preferred embodiments of the invention, and not by way of limitation. Changes can be made to various aspects of the invention, without departing from the scope thereof.

Therefore, the scope of the invention is to be determined not by the illustrative examples set forth above, but by the appended claims and their legal equivalents.

Claims

1. An apparatus, comprising: a base;three or more planar sides connected to the base and to one another, forming an enclosed pyramidal shaped structure having a cavity therein, said structure when viewed from a side comprising a height and a width;an inlet for placement of a flowable material having a density greater than sea water into said cavity;an outlet adapted to permit water within said cavity to flow out of said cavity, in response to placement of said flowable material within said cavity;one or more attachment points for a deployment line; andone or more attachment points for a mooring line.

2. The apparatus of claim 1, wherein said height is between about 30% and 40% of said width.

3. The apparatus of claim 1, wherein said inlet further comprises a pressure regulating element.

4. The apparatus of claim 1, wherein said outlet comprises a pressure regulating element.

5. The apparatus of claim 1, wherein said inlet and said outlet further comprise pressure regulating elements.

6. The apparatus of claim 1, wherein one or more of said sides comprise openings therein, and wherein said one or more attachment points for a mooring line comprise plates fastened over at least one of said openings, and ring elements attached to said plates.

7. The apparatus of claim 1, wherein said three or more sides comprise four sides, upper ends of said four sides terminating in a flat surface forming a truncated pyramidal shape, at least one of said attachment points positioned substantially centrally on said flat surface.

8. The apparatus of claim 7, wherein said flat surface comprises a side length, and wherein said side length is between about 20% and 30% of said width.

9. The apparatus of claim 1, wherein one or more of said sides comprises a skirt section extending beyond said base.

10. An anchor, comprising: a base;four planar sides connected to the base and to one another, forming an enclosed pyramidal shaped structure having a cavity therein, said structure when viewed from a side comprising a height and a width;an inlet for placement of a flowable material having a density greater than sea water into said cavity;an outlet adapted to permit water within said cavity to flow out of said cavity, in response to placement of said flowable material within said cavity;one or more attachment points for a deployment line; andone or more attachment points for a mooring line.

11. The anchor of claim 10, wherein said height is between about 30% and 40% of said width.

12. The anchor of claim 11, wherein said four sides terminate in a flat upper surface, forming a truncated pyramid shape when viewed from a side.

13. The anchor of claim 12, wherein said flat upper surface has a side length between about 20% and 30% of said width.

14. The anchor of claim 13, wherein an attachment point is positioned on said flat upper surface.

15. The apparatus of claim 14, wherein at least one of said inlet and said outlet further comprise pressure regulating elements.

16. The apparatus of claim 14, wherein one or more of said sides comprise openings therein, and wherein said one or more attachment points for a mooring line comprise plates fastened over at least one of said one or more openings, and ring elements attached to said one or more plates.

17. The apparatus of claim 16, wherein one or more of said sides comprises a skirt section extending beyond said base.