NO20230659A1

NO20230659A1 - Fairlead braking unit

Info

Publication number: NO20230659A1
Application number: NO20230659A
Authority: NO
Inventors: Nikolai Skatškov
Original assignee: Src Group As
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2023-06-14
Also published as: WO2023079350A1

Description

Fairlead Braking Unit

FIELD OF THE INVENTION

This invention relates in general to the field of marine mooring equipment and, in particular, to fairleads used for guiding a mooring line.

BACKGROUND OF THE INVENTION

Fairleads are an important tool in marine environments to guide a line, e.g. a rope, cable or chain, around an object, or to prevent lateral movement of the line. Some fairleads, known as moveable fairleads or rotating fairleads, are capable of rotating around a vertical axis to allow for changes in the direction of the line, without having an angle in the line.

Figure 1 is a schematic diagram showing a moveable fairlead 1 according to a prior art implementation. The moveable fairlead 1 is generally attached to the hull of a floating vessel such as, for example, a ship or floating platform. The moveable fairlead comprises a pair of brackets 10, a rotating support shaft 20 and a guide member 30.

The brackets 10 are for attachment to the floating vessel. For example, the brackets 10 may be welded to the hull of the floating vessel. The rotating support shaft 20 is coupled to the one or more brackets and configured to rotate with respect to the brackets 10. In some implementations, a single rotating support shaft 20 may extend vertically between the two brackets 10, or a pair of rotating support shafts may support the guide member 30 between them.

The guide member 30 typically includes a guide wheel 31 or a fixed guide channel for the cable or chain to pass through. The guide member 30 can include connecting plates 32 e.g. to connect the guide wheel with the rotating support shaft 20. The guide member is attached to the rotating support shaft(s) and is configured to rotate with the rotating support shaft(s). In this way, the fairlead 1 can rotate around a vertical axis and can guide the line without having an angle in the line.

A problem with these moveable fairleads arises where an offshore unit or floating vessel is not anchored and is moving or being moved, and one or more fairleads attached to an exterior of the hull are rotating freely. Freely rotating fairleads can often slam against the floating vessel, causing damage to the vessel and/or the fairlead itself due to the waves and movement of the vessel.

The present invention aims to address these problems in the state of the art.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a braking unit for a moveable fairlead on a floating vessel according to claim 1 .

According to a second aspect of the present invention, there is provided a moveable fairlead according to claim 10.

According to a third aspect of the present invention, there is provided a method of retrofitting a braking unit to a moveable fairlead on a floating vessel according to claim 11.

Optional features are as set out in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example only, to the accompanying drawings, in which:

Figure 1 is a schematic diagram showing a moveable fairlead according to a prior art implementation;

Figure 2 is a schematic diagram showing a braking unit according to an embodiment;

Figure 3 is a schematic diagram showing a braking unit according to an embodiment;

Figure 4 is a side-elevation view showing a braking unit according to an embodiment;

Figure 5 is a cross-section view showing a braking unit according to an embodiment; and

Figure 6 is a flowchart showing a method of retrofitting a braking unit according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a braking unit for attachment to a moveable fairlead, and a method of retrofitting the braking unit to a moveable fairlead. In particular, the braking unit reduces movement of the fairlead by bringing one or more braking pads into contact with a stopper plate.

Figure 2 of the accompanying drawings shows a braking unit 100 for a moveable fairlead 1 on a floating vessel according to an embodiment. The braking unit 100 comprises a stopper plate 110, one or more braking pads 120 and a braking actuator 130.

The stopper plate 110 is configured for coupling to a rotating support shaft of the moveable fairlead 1. The stopper plate 110 is configured to be coupled in a position where an axis of the rotating support shaft is normal to the stopper plate 110. The stopper plate is of part-disc shape. The braking pads 120 are configured to resist a rotational movement of the stopper plate 110. The braking actuator 130 is configured to move the braking pads 120 into a braking position where the braking pads 120 are in contact with the stopper plate 110.

In this way, the braking unit 100 can resist swinging of a moveable fairlead 1 which has the potential to cause damage to the floating vessel or the fairlead 1 itself. The braking unit 100 can be provided in a modular unit which can be retrofitted to an existing fairlead 1 in situ on a floating vessel.

The braking unit 100 can be attached or retrofitted to any form of floating vessel, e.g. a ship or floating platform. The braking unit 100 can be made compatible with any of the large variety of moveable fairleads used on such floating vessels. For example, the braking unit 100 can be attached to a fairlead 1 with a guide wheel or guide channel, with or without connecting side plates, and with a single support shaft or a pair of support shafts supporting a guide member in between. The braking unit 100 can be made compatible with any other variation in form or size of moveable fairlead 1 .

Figure 3 shows an external view of the braking unit 100 and the moveable fairlead 1. In some examples, the stopper plate 110 may be configured to directly attach to the rotating support shaft. In some examples, the stopper plate 110 may be configured to attach to a guide member which is attached to the rotating support shaft and configured to rotate with the rotating support shaft. For example, the stopper plate 110 may be configured to attach to a connecting side plate which is coupled to the rotating support shaft, or supported between two rotating support shafts, and supports a guide wheel.

In some examples, the stopper plate 110 may be shaped for attachment to the moveable fairlead 1. For example, the stopper plate 110 may include a notch configured to fit around the rotating support shaft or any other rotating element of the moveable fairlead 1. The stopper plate 110 may be formed from steel, or any material suitable for marine construction.

In some embodiments, the stopper plate 110 may have a semi-circular form with a straight edge and a semi-circular edge. The stopper plate 110 may be configured to be coupled to the rotating support shaft at a mid-point of the straight edge.

In this way, the stopper plate 110 can be directly attached at a central point of rotation to a rotating element of the moveable fairlead 1. As the stopper plate 110 is rotated by movement of the moveable fairlead 1 , the stopper plate 110 can pass the one or more braking pads 120 in a semi-circular arc, providing a consistent surface for braking the fairlead 1.

Alternatively, in some examples, the stopper plate 110 may be formed from any sector of a circle e.g. subtending an angle of more or less than 180, and configured to be attached at the centre point. In some examples, the stopper plate 110 may include a curved edge passing substantially through the central point. In some examples, the semi-circular edge may be smooth or may be formed or shaped as required.

In some embodiments, the stopper plate 110 may be configured to extend through a socket 140 formed in a hull of the floating vessel. The braking pads 120 and braking actuator 130 may be arranged in an interior of the hull.

Figure 4 is a side-elevation view showing a braking unit 100 according to an embodiment. The braking unit 100 is shown from an interior of the hull. As shown, a socket 140 may be formed in the hull and the stopper plate 110 can extend through the socket 140 to the interior of the hull. A portion of the stopper plate 110 furthest from an attachment point of the stopper plate 110 may extend through the socket 140, i.e. a portion of the semicircular edge may be inside the hull of the floating vessel.

In some examples, the braking pads 120 may be arranged in pairs above and below the stopper plate 110. The braking pads 120 may be formed from steel, or any material suitable for marine construction. In some examples, the material of the stopper plate 110 and the braking pads 120 may be selected to avoid galvanic pairs, to prevent excess corrosion.

In some examples the socket 140 may be rectangular, as shown. The size of the socket 140 may be approximately the same as the portion of the stopper plate 110 extending through. In some examples, the socket 140 may be sized such that the full stopper plate 110 will not pass through. Alternatively, the socket 140 may be any shape or size which allows at least a portion of the plate to pass through. In some examples, the socket 140 may be already present on the hull, e.g. a maintenance hatch for the fairlead 1 , or the socket 140 may be cut into the fairlead 1 in order to retrofit the braking unit 100.

In some examples, the socket 140 may include a seal, e.g. a rubber seal arranged to fit tightly against the stopper plate 110 and allow rotational movement while preventing water from entering the hull. Alternatively, or in addition, the braking unit 100 may be separately sealed to prevent the ingress of water from inside the socket 140.

By extending stopper plate 110 through the hull, and arranging the braking unit 100 in the interior of the hull, the braking unit 100 can be protected from seawater. For example, where the socket 140 and/or braking unit 100 is sealed or substantially sealed, the braking unit 100 can be isolated from seawater. In this way moving/mechanical parts of the braking unit 100 can be protected from corrosion. In addition, the braking unit 100 can be accessed more easily from the interior of the floating vessel, to maintain or repair components of the braking unit 100.

Alternatively, the braking unit 100 may be positioned on an exterior of the floating vessel e.g. where it is not possible to provide a socket 140 in the hull of the floating vessel. Individual components of the braking unit 100, e.g. the braking actuator 130 may be individually sealed to isolate them from seawater.

In some embodiments, the braking unit 100 may further include a rectangular enclosure 150 attached to the socket 140. The enclosure 150 may be arranged to receive the stopper plate 110 within. The braking pads 120 may be embedded in an upper and/or lower wall of the enclosure 150.

Figure 5 is a cross-section view showing a braking unit 100 according to an embodiment. As shown, the enclosure 150 may be a rectangular box shape which is open at one side. The open side of the enclosure 150 may be configured to attach to an interior side of the hull of the floating vessel, with the socket 140 within the open side. In this way, the interior of the enclosure 150 may be open to the exterior of the floating vessel.

The enclosure 150 may include one or more openings in an upper and/or lower wall of the enclosure 150. Each opening may be configured to receive one of the one or more braking pads 120. The openings may include seals configured to surround the braking pads 120 or, alternatively, a shoe or shell of each brake pad, to isolate the braking actuator 130 from the interior of the enclosure 150.

In this way, the mechanical components of the braking unit 100 such as, for example, the actuator, can be isolated from seawater which may enter the hull through the socket 140. The enclosure 150 can provide a mounting point for the braking pads 120 such that the braking pads 120 are arranged in a correct position with respect to the stopper plate 110. In addition, the braking pads 120 can be mounted such that braking pads 120 are exposed to the interior of the enclosure 150 but the braking actuator 130 is isolated from the interior of the enclosure 150.

In some embodiments, the braking actuator 130 may include one or more hydraulic cylinders. In some examples, the braking actuator 130 may include one or more hydraulic cylinders for each of the one or more braking pads 120, or a hydraulic cylinder may be connected to multiple braking pads 120. The braking actuator 130 may include a shoe or shell configured to hold the braking pads 120. The shoe or shell may be connected to the hydraulic cylinder or any other form of actuator.

By implementing hydraulic cylinders, the braking unit 100 is capable of exerting a sufficiently large braking force on the stopper plate. The hydraulic cylinders allow for electronic control through a direct or remote operation. By using bi-directional hydraulics the braking actuator 130 can be activated or deactivated to control a braking function. Alternatively, a one directional hydraulic cylinder may be used and the braking actuator 130 may be biased to a deactivated position e.g. by one or more springs. In this way, a fail-off mechanism can be provided. If required, a fail-on mechanism can be provided by reversing the bias/actuation direction. In some examples, a controllable level of braking force can be applied by the hydraulic cylinders.

Alternatively, the braking actuator 130 may be implemented by other means e.g. an electric motor or pneumatic system, or a manual actuator may be used e.g. a pump or lever based actuator. A manual actuator may be provided in addition to any other actuator as a failsafe in the event of a mechanical failure or power outage.

In some embodiments, the braking unit 100 may include a braking controller to control the braking actuator 130. The braking controller may be implemented by any suitable processor or processing unit.

The term "processor" may refer to a computational element that is operable to respond to and process instructions to perform operations. In an example, the processor may be a microprocessor, a microcontroller, a complex instruction set computing (CISC) microprocessor, a reduced instruction set (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or any other type of processing circuit, for example as aforementioned. The processor may be operated individually or as a part of a computation system.

The braking controller may be configured to activate the braking actuator 130, and/or deactivate the braking actuator 130. The braking controller may also be configured to control the braking actuator 130 to apply a certain braking force to the braking pads 120. The braking controller may be configured to control the braking actuator 130 to increase and/or decrease the braking force applied to the braking pads 120.

In this way, the braking controller provides improved control of a braking function, in a way which can be operated directly or remotely. Fine grained control over the timing and braking force can be provided by the braking controller. Where a plurality of braking actuators are provided, the braking controller can ensure synchronised control, improving braking efficiency and reducing component wear.

In some embodiments, the braking controller may be remotely operable through a wired and/or wireless connection. For example, the braking controller may be operated from a central control point of the floating vessel, e.g. a bridge or cockpit. Alternatively, or in addition, the braking may be operated from a control point removed from the floating vessel. The braking controller may be remotely operable through a connection including any selection or combination of suitable wired connections (e.g. serial, parallel, USB, ethernet etc.) and wireless connections (e.g. Bluetooth, Wi-Fi, cellular network, satellite network etc.).

By remotely operating, the braking unit 100 removes the need to reach the location of the fairlead 1 on an interior or exterior of the hull. In some cases, this can remove the need to raise the floating vessel out of the water, or reach the fairlead 1 underwater to control the braking unit 100. Where braking units 100 are installed on multiple fairleads, the remote operation allows the synchronised operation of some or all of the fairleads. In this way, the braking unit 100 can be more responsive, e.g. to changing weather conditions, or the operation can be more effectively synchronised to a mooring/relocating operation of the floating vessel.

Alternatively, the braking controller may be operated directly, e.g. via a terminal or control panel co-located with the braking unit 100.

In some embodiments, the stopper plate 110 may include at least one locking hole extending through the stopper plate 110. The braking unit 100 may include a locking pin 160 configured to pass through the stopper plate 110 hole.

In some examples, the stopper plate 110 may include a plurality of locking holes. For example, the locking holes may be spaced along a semi-circular arc, such that each locking hole is aligned with the locking pin 160 as the stopper plate 110 rotates through a 180 degrees. In some examples, the locking pin 160 and locking holes may have a corresponding shape, e.g. both may be circular or square in profile.

In this way, the stopper plate 110 and coupled fairlead 1 can be fixed in position when a rotation of the fairlead 1 is stopped. This can prevent swinging of a moveable fairlead 1 which has the potential to cause damage to the floating vessel or the fairlead 1 itself. By providing a locking mechanism, the braking unit 100 can release the braking actuator 130, reducing wear on the braking components and/or power consumption of the braking actuator 130.

Alternatively, in some embodiments a locking unit of other type may be provided. For example, the braking actuator 130 may include a clamping mechanism to clamp the actuator in place or a locking element may be configured to engage with an edge of the stopper plate or engage the rotating support shaft directly.

Fig. 4 shows an example of a locking pin 160, in position. In some embodiments, as shown, the braking unit 100 may include a hydraulic locking actuator 170 configured to move the locking pin 160 through the locking hole in the stopper plate 110.

By implementing a hydraulic actuator, the braking unit 100 allows for electronic control of the locking mechanism through a direct or remote operation, substantially as described above with respect to the braking actuator 130. By using bi-directional hydraulics the locking actuator 170 can be activated or deactivated to control a locking function by moving the locking pin 160 in and out of the locking hole. Alternatively, a one directional hydraulic cylinder may be used and the locking actuator 170 may be biased to a deactivated position e.g. by one or more springs. In this way, a fail-off mechanism can be provided. If required, a fail-on mechanism can be provided by reversing the bias/actuation direction.

Alternatively, the locking actuator 170 may be implemented by other means e.g. an electric motor or pneumatic system, or a manual actuator may be used e.g. a pump or lever based actuator. A manual actuator may be provided in addition to any other actuator as a failsafe in the event of a mechanical failure or power outage.

Also provided is a moveable fairlead 1 , according to an embodiment. The moveable fairlead 1 comprises one or more brackets, a rotating support shaft, a guide member and a braking unit 100 substantially as described above.

The brackets are configured for attachment to a floating vessel. For example, the brackets may be welded to the hull of the floating vessel. The moveable fairlead 1 may be attached to any form of floating vessel, e.g. a ship or floating platform.

The rotating support shaft is coupled to the one or more brackets and configured to rotate with respect to the brackets. In some implementations, a single rotating support shaft may extend vertically between the two brackets, or a pair of rotating support shafts may support the guide member between them.

The guide member is attached to the rotating support shaft and is configured to rotate with the rotating support shaft. The guide member may include a guide wheel or a fixed guide channel for a cable or chain to pass through. In some examples, the guide member may include one or more connecting plates e.g. to connect the guide wheel with the rotating support shaft.

As described above, the stopper plate 110 of the braking unit 100 is coupled to the rotating support shaft in a position where an axis of the rotating support shaft is normal to the stopper plate 110.

Figure 5 of the accompanying drawings shows a flowchart representing a method of retrofitting a braking unit according to an embodiment. The method starts at step S11.

At step S12, the method may include cutting a socket into the hull of a floating vessel.

In some examples the socket may be rectangular. The size of the socket may be approximately the same as a portion of the stopper plate of the braking unit which is to be passed through the socket. In some examples, the socket may be sized such that the full stopper plate will not pass through, Alternatively, the socket may be any shape or size which allows at least a portion of the plate to pass through.

In some examples, the socket may include a seal, e.g. a rubber seal arranged to fit tightly against the stopper plate and allow rotational movement while preventing water from entering the hull. Alternatively, or in addition, the braking unit may be separately sealed to prevent the ingress of water from inside the socket.

Alternatively, in some examples, a socket may be already present on the hull, e.g. a maintenance hatch for the fairlead. Alternatively, in some examples, the braking unit may be positioned on an exterior of the floating vessel e.g. where it is not possible to provide a socket in the hull of the floating vessel. Individual components of the braking unit, e.g. the braking actuator may be individually sealed to isolate them from seawater.

At step S13, the method may include passing a portion of the stopper plate through a socket in a hull of the floating vessel, and positioning the braking pads and braking actuator adjacent to the portion of the stopper plate within the hull.

By extending the stopper plate through the hull, and arranging the braking unit in the interior of the hull, the braking unit can be protected from seawater. For example, where the socket and/or braking unit is sealed or substantially sealed, the braking unit can be isolated from seawater. In this way moving/mechanical parts of the braking unit can be protected from corrosion. In addition, the braking unit can be accessed more easily from the interior of the floating vessel, to maintain or repair components of the braking unit.

At step S14, the method includes coupling the stopper plate of the braking unit to a rotating support shaft of the moveable fairlead in a position where an axis of the rotating support shaft is normal to the stopper plate.

In some examples, the stopper plate may be configured to directly attach to the rotating support shaft. In some examples, the stopper plate may be configured to attach to a guide member which is attached to the rotating support shaft and configured to rotate with the rotating support shaft. For example, the stopper plate may be configured to attach to a connecting side plate which is coupled to the rotating support shaft, or supported between two rotating support shafts, and supports a guide wheel.

In some examples, the stopper plate may be shaped for attachment to the moveable fairlead. For example, the stopper plate may include a notch configured to fit around the rotating support shaft or any other rotating element of the moveable fairlead. The stopper plate may be formed from steel, or any material suitable for marine construction. The stopper plate may be welded to the rotating support shaft and/or guide member of the moveable fairlead.

In some embodiments, the stopper plate may have a semi-circular form with a straight edge and a semi-circular edge. The stopper plate may be configured to be coupled to the rotating support shaft at a mid-point of the straight edge.

In this way, the stopper plate can be directly attached at a central point of rotation to a rotating element of the moveable fairlead. As the stopper plate is rotated by movement of the moveable fairlead, the stopper plate can pass the one or more braking pads in a semi-circular arc, providing a consistent surface for braking the fairlead.

Alternatively, in some examples, the stopper plate may be formed from any sector of a circle e.g. subtending an angle of more or less than 180, and configured to be attached at the centre point. In some examples, the stopper plate may include a curved edge passing substantially though the central point. In some examples, the semi-circular edge may be smooth or may be formed or shaped as required.

At step S13, the method may include attaching a rectangular enclosure to the socket. The enclosure may be arranged to receive the stopper plate within. The enclosure may be a rectangular box shape which is open at one side. The open side of the enclosure may be configured to attach to an interior side of the hull of the floating vessel, with the socket within the open side. In this way, the interior of the enclosure may be open to the exterior of the floating vessel.

The braking pads may be embedded in an upper and/or lower wall of the enclosure. The enclosure may include one or more openings in an upper and/or lower wall of the enclosure. Each opening may be configured to receive one of the one or more braking pads. The openings may include seals configured to surround the braking pads or, alternatively, a shoe or shell of each brake pad, to isolate the braking actuator from the interior of the enclosure.

In this way, the mechanical components of the braking unit such as, for example, the actuator, can be isolated from seawater which may enter the hull through the socket. The enclosure can provide a mounting point for the braking pads such that the braking pads or arranged in a correct position with respect to the stopper plate.

In addition, the braking pads can be mounted such that braking pads are exposed to the interior of the enclosure but the braking actuator is isolated from the interior of the enclosure.

The method finishes at step S16.

Although aspects of the invention herein have been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the scope of the invention as defined by the appended claims.

Claims

1 A braking unit for a moveable fairlead on a floating vessel, comprising:

a stopper plate for coupling to a rotating support shaft of the moveable fairlead in a position where an axis of the rotating support shaft is normal to the stopper plate;

one or more braking pads configured to resist a rotational movement of the stopper plate; and

a braking actuator configured to move the braking pads into a braking position where the braking pads are in contact with the stopper plate.

2. The braking unit of claim 1 , wherein the stopper plate has a semi-circular form with a straight edge and a semi-circular edge and is configured to be coupled to the rotating support shaft at a mid-point of the straight edge.

3. The braking unit of claim 1 or claim 2, wherein the stopper plate is configured to extend through a socket in a hull of the floating vessel, and the braking pads and braking actuator are arranged in an interior of the hull.

4. The braking unit of claim 3, further comprising a rectangular enclosure attached to the socket and arranged to receive the stopper plate within, wherein the braking pads are embedded in an upper and/or lower wall of the enclosure.

5. The braking unit of any preceding claim, wherein the braking actuator includes one or more hydraulic cylinders.

6. The braking unit of any preceding claim, further comprising a braking controller to control the braking actuator.

7. The braking unit of claim 6, wherein the braking controller is remotely operable through a wired and/or wireless connection.

8. The braking unit of any preceding claim, wherein the stopper plate includes at least one locking hole extending through the stopper plate; and

wherein the braking unit further comprises a locking pin configured to pass through the stopper plate hole.

9. The braking unit of claim 8, further comprising a hydraulic locking actuator configured to move the locking pin through the locking hole in the stopper plate.

10. A moveable fairlead, comprising:

one or more brackets for attachment to a floating vessel;

a rotating support shaft coupled to the one or more brackets and configured to rotate with respect to the brackets;

a guide member attached to the rotating support shaft and configured to rotate with the rotating support shaft; and

the braking unit of any preceding claim, wherein the stopper plate of the braking unit is coupled to the rotating support shaft in a position where an axis of the rotating support shaft is normal to the stopper plate.

11. A method of retrofitting the braking unit of any of claims 1 to 9 to a moveable fairlead on a floating vessel, comprising;

coupling the stopper plate of the braking unit to a rotating support shaft of the moveable fairlead in a position where an axis of the rotating support shaft is normal to the stopper plate.

12. The method of claim 11 , wherein coupling the stopper plate comprises directly attaching the stopper plate to the rotating support shaft and/or attaching the stopper plate to a guide member which is attached to the rotating support shaft and configured to rotate with the rotating support shaft.

13. The method of claim 12, further comprising: passing a portion of the stopper plate through a socket in a hull of the floating vessel, and positioning the braking pads and braking actuator adjacent to the portion of the stopper plate within the

14. The method of claim 13, wherein positioning the braking pads and braking actuator comprises attaching a rectangular enclosure to the socket, wherein the enclosure is arranged to receive the stopper plate within, and the braking pads are embedded in an upper and/or lower wall of the enclosure.

15. The method of claim 13 or claim 14, further comprising cutting the socket into the hull of the floating vessel.