Gravitation anchor for offshore anchoring of ships and platforms

Abstract

The present invention is related to a gravitation anchor for offshore anchoring of ships and platforms, comprising a main body (10) with a longitudinal axis of revolution (11), comprising a means of stabilization (14), whereby the means of stabilization (14) comprises a means of automatic activation (140). Optionally, the means of stabilization comprises at least one stabilizer (14), whereby each stabilizer (14) comprises an end pivotally attached (141) to the gravitation anchor (1), and a free end, whereby when the stabilizer (14) is in a retracted position, the free end is positioned closer to the main body (10) of the gravitation anchor (1), and whereby when the stabilizer (14) is in an extended position, the free end is positioned away from the main body (10) of the gravitation anchor (1).

Claims

1. A gravitation anchor (1) for offshore anchoring of ships and platforms, comprising a main body (10) having a longitudinal axis of revolution (11), and at least one stabilizer (14), the at least one stabilizer (14) comprising an end pivotally attached (141) to the gravitation anchor, and a free end; wherein the at least one stabilizer (14) further comprises a protrusion formed on at least one face of the at least one stabilizer (14), wherein the protrusion automatically activates the at least one stabilizer; wherein when the at least one stabilizer (14) is activated, the at least one stabilizer (14) moves from a retracted position, wherein the free end is positioned closer to the main body (10) of the gravitation anchor (1), to an extended position, wherein the free end is positioned away from the main body (10) of the gravitation anchor (1); wherein when the at least one stabilizer (14) is activated, the at least one stabilizer pivotally rotates in a direction toward a rearward end of the gravitation anchor (1); wherein the protrusion is positioned along at least one surface of the at least one stabilizer (14); wherein when the at least one stabilizer (14) is in the retracted position, the protrusion is formed so as to extend away from the axis of revolution (11) of the gravitational anchor (1) as the protrusion reaches the free end of the at least one stabilizer (14); and wherein the protrusion extends from the at least one surface of the at least one stabilizer (14) in a direction perpendicular to the direction in which the at least one stabilizer (14) pivotally rotates.

2. The gravitation anchor (1), according to claim 1, wherein the main body (10) of the gravitation anchor (1) comprises fins (12) disposed on at least one portion of its length.

3. The gravitation anchor (1), according to claim 1, further comprising at least three fins (12).

4. The gravitation anchor (1), according to claim 1, further comprising a connector element (13) connecting to an anchor line (2) at an upper end thereof.

5. The gravitation anchor (1), according to claim 1, wherein the at least one stabilizer (14) comprises a rigid plate.

6. The gravitation anchor (1), according to claim 1, wherein the at least one stabilizer (14) is attached to a fin of the gravitation anchor (1).

7. The gravitation anchor (1), according to claim 1, wherein the at least one stabilizer (14) comprises a stroke limiting element (142), which limits a rotation stroke of the at least one stabilizer (14) and sets the final position thereof.

8. The gravitation anchor (1), according to claim 1, wherein the at least one stabilizer (14) detaches from the gravitation anchor (1) upon impact against a seabed (6).

9. The gravitation anchor (1), according to claim 7, wherein the stroke limiting element (142) is a pin attached to a fin where the at least one stabilizer (14) is attached.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The detailed description below makes reference to the accompanying figures and their respective reference numbers, representing embodiments of the present invention.

(2) FIG. 1 illustrates a schematic representation of the procedure for installation of a traditional gravitation anchor.

(3) FIG. 2 illustrates a view of a gravitation anchor as defined by an optional embodiment of the present invention.

(4) FIG. 3 illustrates a view of the gravitation anchor in FIG. 2, as defined by an optional embodiment, whereby the means of stabilization is retracted.

(5) FIG. 4 illustrates a view of the gravitation anchor in FIG. 2, whereby the means of stabilization is moving into the final position of use.

(6) FIG. 5 illustrates a detailed view of the means of stabilization illustrated in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

(7) Preliminarily, it is emphasized that the following description will start with a preferred embodiment of the invention, applied to a gravitation anchor 1. However, as will be apparent to one skilled in the art, changes in the object described may be made within the scope of protection of the invention.

(8) The present invention relates to the improvement of gravitation anchors as illustrated in FIG. 1, whereby a schematic representation of the installation of a traditional gravitation anchor 1 is shown, whereby the gravitation anchor 1 is ready to be cast. In this procedure, the gravitation anchor 1 is connected to a first end 2a of an anchor line 2, in which the anchor line 2 is suspended from a second end 2b, with the aid of an auxiliary casting line 3a connected to the platform 4 to be anchored.

(9) In addition, anchor line 2 is suspended by an intermediate point, with the aid of a second auxiliary casting line 3b, by an auxiliary vehicle 5. The anchor is then positioned at a specific height and released for free fall until it reaches the seabed 6, being embedded.

(10) The first auxiliary casting line 3a is then retracted until anchor line 2 reaches platform 4 and is connected thereto. That is how the platform 4 is anchored. Preferably, more than one anchor 1 is used at different points.

(11) The present invention provides a gravitation anchor comprising means of stabilization 14 to stabilize the downward movement of the anchor, increasing its speed and its load capacity, and enabling deeper embedding of anchor 1 when it hits the seabed 6.

(12) FIG. 2 illustrates a view of a gravitation anchor 1 as defined by an optional embodiment of the present invention, wherein it comprises means for its stabilization 14, optionally attached on its upper portion.

(13) Optionally, the anchor comprises a main body 10 with a longitudinal axis of revolution 11, whereby the main body 10 comprises fins 12 in at least one portion of its length.

(14) Preferably, at least two fins 12 are adopted, preferably three fins 12, and more preferably four fins 12.

(15) Optionally, the gravitation anchor 1 comprises a connector element 13 for connection to an anchor line 2 at its upper end.

(16) FIG. 3 illustrates a view of gravitation anchor 1 of the present invention, as defined by an optional embodiment, whereby the means of stabilization 14 is retracted. FIG. 4 illustrates a view of gravitation anchor 1 of the present invention, as defined by an optional embodiment, whereby the means of stabilization 14 is moving into the final position of use.

(17) Preferably, the means of stabilization 14 comprises at least one stabilizer 14, whereby each stabilizer 14 comprises an end pivotally attached 141 to the gravitation anchor 1 and a free end, so that when the means of stabilization 14 is in its retracted position, the free end is positioned closer to the main body 10 of the gravitation anchor 1. In turn, when the means of stabilization 14 is in its extended position, the free end is positioned away from the main body 10 of the gravitation anchor 1. Optionally, the stabilizer 14 comprises a rigid plate.

(18) Optionally, each stabilizer 14 is attached in a coplanar fashion on a fin of the gravitation anchor 1. As shown, each fin comprises a stabilizer 14; however, other embodiments are provided. For example, the number of stabilizers 14 may be greater than the number of fins 12, whereby each fin comprises more than one stabilizer 14, or the number of stabilizers 14 is less than the number of fins 12.

(19) As defined by the present invention, the means for stabilizing the gravitation anchor comprises a means of automatic activation 140, so that each means of stabilization 14 is automatically activated when the gravitation anchor 1 is positioned to be cast or when it is immersed in water and starts to move.

(20) As can be best seen in FIG. 5, which illustrates in detail the means of stabilization 14 illustrated in FIGS. 2, 3 and 4, the means of automatic activation 140 of each stabilizer 14 is formed by a protrusion in at least one of the faces of the stabilizer 14, whereby the protrusion 140 may be formed by a jut in the stabilizer 14 itself, or by an element attached to the stabilizer 14, such as a plate. Thus, when the gravitation anchor 1 starts the downward movement into the water, hydrodynamic forces F will boost each stabilizer 14, causing them to rotate around an axis that is pivotally attached 141.

(21) Optionally, so as to optimize the hydrodynamic forces mentioned, the protrusion 140 is positioned along at least one surface of the stabilizer 14, whereby when the stabilizer 14 is in its retracted position, illustrated in FIG. 3, the protrusion moves away from the axis of revolution 11 of the gravitation anchor 1, approaching the free end of the stabilizer 14.

(22) Note that other embodiments of means of automatic activation 140 can, however, be adopted, staying within the scope of protection of the present invention. Merely as an example, alternatively, the means of automatic activation 140 may comprise a system of cables whereby the stabilizer 14 is activated and positioned in its position of use by gravitational force, when the gravitation anchor 1 is suspended. Other embodiments can also be adopted.

(23) Optionally, the gravitation anchor 1 comprises a stroke limiting element 142 of the stabilizer 14, adapted to limit the rotation stroke of the stabilizer 14, defining the final position thereof.

(24) As illustrated by the optional embodiment of FIGS. 2, 3, 4 and 5, the stroke limiting element 142 is a pin attached to the fin where the respective stabilizer 14 is attached.

(25) Optionally, the gravitation anchor 1 comprises a locking element (not shown), adapted for locking each stabilizer 14 in its final position, preventing it from going back to its retracted position, once it reaches its final position of use.

(26) Optionally, in order to prevent the means of stabilization 14 from negatively interfering with the load capacity of the gravitation anchor 1 of the present invention, it can be designed to detach from the gravitation anchor 1 upon impact with the seabed 6. Such detachment may take place by a break in the means of stabilization 14 itself, or a break in the element responsible for attaching the means of stabilization 14 to the gravitation anchor 1.

(27) Thus, the present invention provides a gravitation anchor 1 comprising means of stabilization 14, without requiring rework for positioning the means of stabilization 14. As such, it allows the anchor to reach a higher final speed, which increases its load capacity and thus provides deeper embedding thereof into the seabed.

(28) In addition, when the embodiment in which the means of stabilization 14 is designed to detach from the gravitation anchor 1 at the time of impact against the seabed 6 is adopted, it minimizes the possible negative impact of the means of stabilization 14 on the embedding of the gravitation anchor 1, increasing the effect of its use.