System for Stabilizing a Vessel Against a Stationary Object

Abstract

Vessel (60), comprising a transverse bow (62) with an elongated bow fender (10) protruding with respect to the bow (62), which bow fender (10) is designed to be pushed against a stationary object (50), said vessel 60) further comprises at least two engagement arms (20) with telescopic parts (22,24), said engagements arms (20) are mounted in a position above the bow fender (10) and facing each other, and each engagement arm (20) is pivotable against each other for engagement with the stationary object (50) from opposite directions. Each engagement arm (20) comprises a tiltable engagement pad (26) with a contacting surface (26a) creating stabilizing contact between the contacting surfaces (26a) of the engagement pads (26) and at least a part of the stationary object (50), said engagement pads (26) being tiltable about an axis running in same longitudinal direction as the engagement arms (20).

Claims

1. A vessel, comprising a transverse bow with an elongated bow fender protruding in a forward direction with respect to the bow, which bow fender is designed to be pushed against a stationary object, said vessel further comprises at least two engagement arms with several telescopic parts, said engagements arms are mounted in a position above the bow fender and facing each other, and each engagement arm is pivotable against each other for engagement with the stationary object from opposite directions, each engagement arm comprises a tiltable engagement pad with a contacting surface creating stabilizing contact between the contacting surfaces of the engagement pads and at least a part of the stationary object, said engagement pads being tiltable about an axis running in same longitudinal direction as the engagement arms, wherein the telescopic parts of each engagement arm comprise a first telescopic part and a second housing part, and the engagement pad is tiltable supported in a hinged connection on an outer free end of the first telescopic part.

2. The vessel according to claim 1, wherein the first telescopic part is extractable and slidably accommodated in the second housing part, and said second housing part is pivotably supported in a pivot connection.

3. The vessel according to claim 2, wherein a first pressure cylinder is connected between the first telescopic part and the second housing part, providing extraction and retraction of the first telescopic part with respect to the second housing part.

4. The vessel according to claim 2, wherein a second pressure cylinder is connected to the second housing part in an area distal to said pivot connection, providing the pivot movement of the second housing part.

5. The vessel according to claim 4, wherein the second housing part comprises one or more slide guides guiding the pivot movement.

6. The vessel according to claim 1, wherein said hinged connection on the outer free end of the first telescopic part comprises one or more rubber blocks preventing unwanted tilting movement of the engagement pad with respect to the first telescopic part.

7. The vessel according to claim 1, wherein the bow fender comprises an elongated fender made of rubber.

8. The vessel according to claim 1, wherein the bow fender comprises an elongated fender made of polyurethane.

9. The vessel according to claim 1, wherein the bow fender on a front face comprises one or more impressions accommodating at least a part of the stationary object, and wherein the stabilizing contact between the contacting surfaces of the engagement pads when the engagement arms are activated prevent any substantial movement of said part of the stationary object with respect to the bow fender.

10. The vessel according to claim 1, wherein the contacting surface of the tiltable engagement pad is made of rubber.

11. The vessel according to claim 1, wherein the contacting surface of the tiltable engagement pad is made of polyurethane.

12. A stabilizing apparatus for a vessel, comprising at least two engagement arms with several telescopic parts, said engagements arms are facing each other, and each engagement arm is pivotable against each other for engagement with a stationary object from opposite directions, each engagement arm comprises a tiltable engagement pad with a contacting surface creating stabilizing contact between the contacting surfaces of the engagement pads and at least a part of the stationary object, said engagement pads being tiltable about an axis running in same longitudinal direction as the engagement arms, wherein the telescopic parts of each engagement arm comprise a first telescopic part and a second housing part, and the engagement pad is tiltable supported in a hinged connection on an outer free end of the first telescopic part.

13. The stabilizing apparatus according to claim 12, wherein the first telescopic part is extractable and slidably accommodated in the second housing part, and said second housing part is pivotably supported in a pivot connection.

14. The stabilizing apparatus according to claim 12, wherein a first pressure cylinder is connected between the first telescopic part and the second housing part, providing extraction and retraction of the first telescopic part with respect to the second housing part.

15. The stabilizing apparatus according to claim 12, wherein a second pressure cylinder is connected to the second housing part in an area distal to said pivot connection, providing the pivot movement of the second housing part.

16. The stabilizing apparatus according to claim 15, wherein the second housing part comprises one or more slide guides guiding the pivot movement.

17. The stabilizing apparatus according to claim 12, wherein said hinged connection on the outer free end of the first telescopic part comprises one or more rubber blocks preventing unwanted tilting movement of the engagement pad with respect to the first telescopic part.

18. The stabilizing apparatus according to claim 12, wherein the contacting surface of the tiltable engagement pad is made of rubber.

19. The stabilizing apparatus according to claim 12, wherein the contacting surface of the tiltable engagement pad is made of polyurethane.

Description

DESCRIPTION OF THE FIGURES

[0030] Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, wherein:

[0031] FIG. 1 shows an example of a crew transfer vessel equipped with a bow fender.

[0032] FIG. 2 shows an example of a stationary object, such as an offshore wind turbine foundation.

[0033] FIG. 3 shows a perspective view of an engagement arm with telescopic parts according to the invention.

[0034] FIG. 4a shows a plan view of the engagement arm in a parked and retracted position.

[0035] FIG. 4b shows a plan view of the engagement arm in an activated and extracted position.

[0036] FIG. 5 shows a plan view of a bow fender and two engagement arms in parked and active positions, respective, in where the left engagement arm is in parked and retracted position and the right engagement arm is in active engagement position against a stationary object.

[0037] FIG. 6 shows a plan view of the bow fender and two engagement arms in active positions, in where the left engagement arm is being telescopically extracted and the right engagement arm is in active engagement position against the stationary object.

[0038] FIG. 7 shows a plan view of the bow fender and two engagement arms in active positions, in where the left engagement arm and the right engagement arm are in active engagement positions against the stationary object.

[0039] FIG. 8 shows a front view of the bow fender and two engagement arms in active positions, in where in the left engagement arm and the right engagement arm are in active engagement positions against the stationary object.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0040] The present invention is related to a vessel 60 as shown in FIG. 1, such as a crew transfer vessel discussed previously, equipped with a bow fender 10. At least an upper part of the bow 62 is on a front face flat and is equipped with an elongated bow fender 10 placed transverse on the bow 62. The invention also relates to a stabilizing or engagement apparatus mounted on said vessel 60.

[0041] A wind turbine foundation 52 is shown in FIG. 2 having two vertical support poles/fender bars 50 to protect the wind turbine while the service vessel 60 approach the turbine and allows the service personnel to use a wind turbine ladder 54 between the two support poles for embarking and disembarking. With the vessel's engines/propellers, the vessel's transverse bow fender 10 is pushed against the support poles 50. A vessel 60 with a bow fender 10 according to the invention can be used to adjust or reduce the impact on the support poles, or other foundation, when the vessel 60 approaches and docs at the wind turbine.

[0042] The bow fender 10 can in its simplest form be a rubber fender mounted to a base plate. One example of the bow fender 10, as shown in the drawings, can comprise an elongated rubber fender 12. In the middle of the rubber fender 12 there is a thicker part 14 protruding on a central front side, which is pressed against the support poles 50 and possibly the ladder 54 of the wind turbine foundation 52. The bow fender 10 further comprises, either in the thicker part 14 or adjacent the thicker part 14, an impression 16 for each pole 50 of the wind turbine foundation 52. As seen in FIG. 5, particularly on the left side, the rubber fender 12 can have several protruding steps with different thickness, which from left to center can be a first step with a first thickness, a second thicker step with the impression 16 and a third central and thickest step, in where the impression is located in the transition between the second and third step. The bow fender 10 is as mentioned mounted on the bow of a vessel 60, such as a crew transfer vessel, with the thicker part 14 facing forward.

[0043] The elongated fender 12 is disclosed as made of rubber, but the elongated fender 12 can be made of plastic or other suitable material such as polyurethane. The bow fender 10 is disclosed in relation to a wind turbine foundation but may of course be used with any similar offshore construction.

[0044] Such a bow fender 10 can for instance be approximately 10 m long, and with a thickness of 45 cm and a height of 65-100 cm. Support poles 50, or fender bars, on a typical wind turbine foundation 52 have a diameter of 33 cm, and a center distance of for instance 1.8 m. The thicker part 14 of the bow fender can be accommodated between the support poles 50 when the vessel 60 is pushing forward. The impressions 16 on the bow fender preferably have the same diameter as the support poles 50 of the wind turbine foundation 52.

[0045] FIG. 3 shows an engagement arm according to the invention, and which comprises at least two telescopic parts 22,24, wherein a first telescopic part 22 is movable from a retracted position to an extracted position slidably in a second housing part 24. The first telescopic part 22 is extracted and retraced by using a first pressure cylinder 32 connected between the first telescopic part 22 and the housing part 24, as indicated by the direction of the arrow A. The second housing part 24 is pivotably supported in a pivot connection 28, and the pivot movement is provided by a second pressure cylinder 34 connected to a distal end of the second housing part 24. Hence, the first telescopic part 22 and the second housing part 24 can thus swing or pivot in the direction indicated by the arrow B.

[0046] The pressure cylinders 32,34 can be hydraulic cylinders or pneumatic cylinders, or for that matter electric driven actuators, which can be connected to a control panel on a deck 64 of the vessel 60 or from a bridge of the vessel 60.

[0047] To guide the sideways pivot movement of the two telescopic parts 22,24, the second housing part 24 can be connected to one or more slide guides 36, for instance having a slot 38, straight or curved, in where a stationary pin 40 is moving. The second housing part 24 will thus be forced to move in the same directions as the slots 36.

[0048] An engagement pad 26 is tiltable mounted to an outer end of the first telescopic part 22, wherein the engagement pad 26 is tiltable supported in a hinged connection 30. The engagement pad 26 is tiltable about an axis running longitudinally and parallel to at least the first telescopic part 22 of the engagement arm 20, i.e. running in the same direction as the arrow A. Tilting movement is indicated by the arrow C.

[0049] The back of the engagement pad 26 can comprise one or more small rubber blocks 44 preventing the engagement pad 26 from “falling down” and tilt to much in a downward direction with respect to the first telescopic part 22. The small rubber blocks 44 can be screwed to a back plate of the hinged connection 30 and cover the hinged connection 30, and possibly abutting the outer end 22a of the first telescopic part 22 if the engagement pad 26 tilt too much. The pad of the engagement pad 26 can be made of rubber or polyurethane, and using small rubber blocks 44 on the backside may also counterbalance the engagement pad 26. Optionally, the tilting movement of the engagement pad 26 can be controlled by an actuator (not shown).

[0050] The rubber pad of the engagement pad 26 can be screwed to the back plate of the hinged connection 30, which makes it easy to exchange the pads in they get worn-out.

[0051] The tiltable engagement pad 26 has a contacting surface 26a creating stabilizing contact between the contacting surfaces 26a of the engagement pads 26 and at least a part of the stationary object 50, said engagement pads 26 being tiltable about an axis running in same longitudinal direction as the engagement arms 20.

[0052] In an embodiment (not shown) the engagement pad 26 can be tiltable in two directions, the first direction being about the first axis running in same longitudinal direction as the engagement arm 20 and the second direction being about a second axis running transverse to the first longitudinal axis.

[0053] The telescopic parts 22,24, pressure cylinders 32,34, slide guides 36, etc., can be mounted on a foundation 42, which is mounted on the deck 64 of the vessel 60. The foundation is mounted higher than the bow fender 10 to allow at least the first telescopic part 22 to be able to pivot above and at least partly in front of the bow fender 10.

[0054] During initial docking of the vessel 10 to the wind turbine foundation 52, the bow fender 10 will hit the support poles 50 of the wind turbine foundation 52. If the vessel is 150-175 dwt and the vessel is moving at 1-2 knots, the force will be quite large. As an example, the forces acting on one of the support poles on the wind turbine foundation 52 may vary from 440 kN for a vessel of 150 dwt and speed of 1 knots up to 2330 kN for a vessel of 175 dwt and speed of 2 knots. Dependent of the angle of the bow fender and the speed of the vessel, the combined impact forces on the support points may thus vary from approximately 40 kN to 260 kN. Hence, at least the support poles 50 of the wind turbine foundation 52 can be subjected to large forces.

[0055] FIG. 5 shows the bow fender 10 and two engagement arms 20 in parked and active positions, respective, in where the left engagement arm 20 is in parked and retracted position and the right engagement arm 20 is in active engagement position against a stationary object, such as the support poles 50 of the wind turbine foundation 52. The two engagement arms 20 can be activated simultaneously or separately.

[0056] In FIG. 6 the left engagement arm 20 is being telescopically extracted and the engagement pad 26 is placed near the left pole 50, while the right engagement arm 20 is in active engagement position against the right pole 50. FIG. 7 shows the bow fender 10 and the two engagement arms 20 in active positions, in where the engagement pad 26 of the left engagement arm and the engagement pad 26 of the right engagement arm 20 are in active engagement positions against the two support poles 50 of the wind turbine foundation. FIG. 8 shows a front view of the bow fender 10 and the two engagement arms 20 in active positions.

[0057] When both engagement arms 20 are activated and pushed against the support poles 50 of the wind turbine foundation 52, as particularly seen in FIGS. 7 and 8, the support poles 50 will be accommodated and trapped in the impressions 16 on the bow fender 10, and the stabilizing contact between the contacting surfaces of the engagement pads 26 prevent any substantial movement of the support poles 50 with respect to the bow fender 10 in any direction. However, as the engagement arms are not locked at the backside of the support poles, the support poles will not be subjected to large tensile forces

[0058] When the vessel is rolling transverse to the wind turbine foundation 52, the tiltable engagement pads 26 on the engagement arms 20 provides that even pressure is maintained in the contacting surfaces against the support poles 50, which improves safety.

[0059] It is possible with the present engagement arms 20 to adjust the pressure against the support poles 50, in both transverse and longitudinally direction.