Unloading system for unloading elongated flexible articles, ship comprising such an unloading system and method of using such an

Abstract

The invention provides an unloading system for unloading elongate flexible articles having a minimum bending radius, comprising an unloading chute comprising a sliding surface having a sliding direction, characterized in that the sliding surface has a through-hole, referred to as a wheel groove, the unloading system further includes a laying wheel system including a pulley including a pulley axle positioned in a pulley axle direction transverse to the sliding direction, a pulley surface, and a pulley rotational direction consistent with the sliding direction, the pulley is configured to rotationally move about the pulley axle in the pulley rotational direction; a portion of the sheave surface is flush with the sliding surface and partially fills the sheave groove. The invention also provides a vessel for laying elongated flexible articles comprising the unloading system and a method of using the unloading system and / or the vessel.

Description

TECHNICAL FIELD

[0001] The present invention relates to an overboard unloading system for unloading elongate flexible articles. BACKGROUND

[0002] The field of deploying elongate flexible articles in a marine environment involves laying subsea cables on a seabed or a bed of another body of water. These cables can be telecommunication cables (e.g. optical fiber cables), power cables and seismic survey cables. The field also involves deploying umbilicals, risers and flow lines onto a seabed or into a body of water. These types of elongate flexible articles connect subsea wells, production facilities and other processing equipment to surface facilities or to each other.

[0003] The field plays a vital role in connecting offshore resources to onshore facilities and facilitating various industries including telecommunication, offshore energy production and other subsea infrastructure development.

[0004] Specialized vessels are used to deploy these subsea cables, such as cable-laying vessels with cable unloading systems such as chutes and laying wheels. These cable unloading systems have means to ensure that the elongate flexible articles do not exceed a minimum bend radius during deployment. The minimum bend radius is the bend radius above which the structural integrity of the elongate flexible article is guaranteed.

[0005] These vessels operate in challenging marine environments and are generally adapted to operate better in shallow or deep water. In particular, unloading systems optimized for deep water cable laying have different performance than unloading systems optimized for shallow water cable laying. For example, patent publication WO2023 / 113592 discloses a cable-laying vessel with an unloading system comprising an unloading chute.

[0006] A disadvantage of such vessels is that their unloading systems are generally not designed for optimal operation in both shallow and deep water, nor for operation in wind farms and open sea. The specific choice in unloading system when deploying elongate flexible articles from a vessel in different marine environments affects the alignment and tension control of the elongate flexible articles. The alignment and tension control affects tangling, kinking and excessive bending. In turn, this can damage the elongate flexible articles, damage the cable-laying vessel or unloading system, or cause installation problems.

[0007] A further disadvantage is that the specific design choices can reduce the efficiency of the cable unloading operation depending on the marine environment and increase wear due to, for example, forces exerted on the unloading system by the elongate flexible articles.

[0008] These challenges can be exacerbated when the vessel deploys the cable in adverse weather conditions. SUMMARY

[0009] It is an object of the present invention to overcome at least some of the drawbacks of the solutions existing in the prior art.

[0010] The present invention therefore provides an unloading system for unloading an elongate flexible article having a minimum bend radius. The elongate flexible article is a telecommunication cable (e.g. an optical fiber cable), an electric power cable and a seismic survey cable. Furthermore, the elongate flexible article comprises an umbilical, a riser and a flowline. These elongate flexible articles connect a subsea well, a production facility and other processing equipment to a surface facility or to each other.

[0011] The minimum bend radius is a bend radius above which the structural integrity of the elongate flexible article is guaranteed. If the elongate flexible article is bent above the minimum bend radius and thereby has a bend with a smaller radius, the performance of the elongate flexible article can be deteriorated, the elongate flexible article can be damaged or it can break.

[0012] The unloading system comprises an unloading chute comprising a sliding surface having a sliding direction, characterized in that the sliding surface has a through hole referred to as a wheel groove. The unloading system further comprises a lay wheel system comprising a slide wheel comprising a slide wheel axle, a slide wheel surface and a slide wheel rotation direction. The slide wheel axle is positioned along a slide wheel axle direction transverse to the sliding direction, the slide wheel rotation direction is in line with the sliding direction, the slide wheel is configured to move rotationally around the slide wheel axle along the slide wheel rotation direction; to have a part of the slide wheel surface flush with the sliding surface and to partially fill the wheel groove.

[0013] An advantage of the present invention is that the elongate flexible article will seamlessly extend over the unloading chute and the slide wheel when unloading the elongate flexible article over the slide wheel surface. The elongate flexible article will not be bent at the interface between the unloading chute and the slide wheel surface just to pass the interface. An additional advantage of the present invention is that the friction force exerted by the unloading system on the elongate flexible article will be reduced when unloading the elongate flexible article, in particular when the elongate flexible article extends over the slide wheel while being unloaded. The elongate flexible article and the unloading system will both be less subject to wear from the unloading operation. The unloading operation will be more efficient and the unloading chute will require less maintenance.

[0014] Optionally, the unloading system is characterized in that the wheel groove has a wheel groove shape configured to receive the lay wheel system.

[0015] The advantage of the present invention is that the laying wheel system can be mounted to the unloading system by means of the wheel slot. Thus, the laying wheel system can be mounted or dismounted without dismounting the unloading chute, thereby facilitating the installation, maintenance and dismantling of the unloading system.

[0016] Optionally, the unloading system is characterized in that the pulley further has a pulley radius, and the laying wheel system further comprises: a first wheel guard having a radius equal to the pulley radius; and a second wheel guard having a radius equal to the pulley radius. The first and second wheel guards each comprise: a respective wheel guard surface; a respective wheel guard rotation direction; and a respective wheel guard flange extending radially from the respective wheel guard surface. The first and second wheel guards are positioned axially adjacent to the pulley, wherein the respective wheel guard rotation directions of the first and second wheel guards are in line with the pulley rotation direction, wherein the first wheel guard is positioned on the other side of the pulley, preferably relative to the second wheel guard. The first and second wheel guards are configured to: move rotationally around the pulley wheel axis along the respective wheel guard rotation direction; and flush the wheel guard surface with the sliding surface and partially fill the wheel slot.

[0017] The advantage of the present invention is that the elongated flexible article is guided onto the pulley by means of the wheel guards. Thus, the efficiency of the unloading system according to the present invention is improved by increasing the use of the pulley. The added advantage is that the wheel guards can be moved, thereby optimizing the guidance of the elongated flexible article for the current task.

[0018] Optionally, the unloading system is characterized in that the first and second wheel guard flanges are each configured to ensure that the elongated flexible article has a bend radius at least equal to the minimum bend radius when the elongated flexible article extends along the respective wheel guard flange.

[0019] The advantage of the present invention is that the elongated flexible article having the minimum bend radius is not damaged by excessive bending when the elongated flexible article extends along the wheel guard flange. Thus, the unloading system prevents damage to the cable during the unloading operation, thereby improving the efficiency of the cable unloading operation.

[0020] Optionally, the first and second wheel guard flanges each span a wheel guard flange arc across 1 / 3 (approximately 1 / 3) of the circumference of their respective wheel guard, the respective wheel guard flange arcs each having a wheel guard flange arc midpoint. Preferably, the wheel guard flange is a continuous flange along the wheel guard flange arc. Alternatively, the wheel guard flange is composed of different wheel guard flange portions, with small openings between the wheel guard flange portions, as if the wheel guard flange is a dashed line.

[0021] An advantage of the present invention is that the support provided by the wheel guard flanges can be adjusted depending on the operating conditions, from support along a first portion of the elongate flexible article to support along a second portion of the elongate flexible article that is shorter than the first portion, as the wheel guard flanges guide the elongate flexible article onto the laydown wheel system. In particular, the present invention allows for the configurable lateral portions of the offloading chute to be used. An additional advantage is that the flanges can be stowed away and, at the same time, do not protrude from the offloading system. As a result, the flanges are not constantly exposed to the harsh marine environment, thereby extending the life of the flanges and reducing the need for regular maintenance.

[0022] Optionally, the first and second wheel guards are each configured to move between at least two of the respective wheel guard deep water position, the respective wheel guard shallow water position, and the respective wheel guard free sliding position. Preferably, the first and second wheel guards are each configured to move between the respective wheel guard deep water position, the respective wheel guard shallow water position, and the respective wheel guard free sliding position.

[0023] Preferably, the first and second wheel guards are in their respective wheel guard deep water positions when the respective wheel guard flange arc midpoints are at the wheel guard deep water position angle, preferably 45° from the upright direction in the wheel guard rotational direction, more preferably 43° from the upright direction in the wheel guard rotational direction, and a majority of the respective wheel guard flange along the wheel guard flange arc protrudes through the wheel trough. Preferably, the first and second wheel guards are in their respective wheel guard shallow water positions when the respective wheel guard flange arc midpoints are at the wheel guard shallow water position angle, preferably 60° from the upright direction opposite the wheel guard rotational direction, more preferably 59° from the upright direction opposite the wheel guard rotational direction, and a small portion of the respective wheel guard flange along the wheel guard flange arc protrudes through the wheel trough. Preferably, the first and second wheel guards are in their respective wheel guard free sliding positions when the respective wheel guard flange arc midpoints are at the wheel guard free sliding position angle, preferably 90° from the upright direction opposite the wheel guard rotational direction, and none of the respective wheel guard flange along the wheel guard flange arc protrudes through the wheel trough.

[0024] An additional advantage of the present invention is that the offloading system can be reconfigured to provide the best support for the elongate flexible article depending on the circumstances under which the elongate flexible article is deployed. For example, the operation of the offloading system deployed on a cable laying vessel operating in deep water requires more lateral flexibility than the operation of the offloading system deployed on a cable laying vessel operating in shallow water.

[0025] Optionally, for each sheave, the sheave system further comprises a circular arc sheave rack having a sheave rack center, a sheave pinion, and a sheave motor. The first sheave and the second sheave each further have a sheave center on a respective sheave center axis. The sheave rack is connected to the respective sheave on a sheave side away from the pulley, and the sheave rack center is on the respective sheave center axis. The sheave pinion is driven by the respective sheave motor and is in mesh with the respective sheave rack.

[0026] Optionally, for each sheave, the sheave system further comprises a sheave locking pin, and the first sheave and the second sheave each further comprise a sheave holder. The sheave holder is a hole configured to receive a portion of the respective sheave locking pin, and the first sheave and the second sheave are configured to be fixed when the respective sheave holder receives the respective sheave locking pin.

[0027] An advantage of the invention is that the first sheave and the second sheave can be fixed in a certain position without relying on the sheave motor. This will enable creating a system with simpler actuators, and the sheave motor will not be used with large intensity. This will prolong the service life of the offloading system and reduce the need for regular maintenance.

[0028] Optionally, the first sheave and the second sheave each further comprise a plurality of sheave holders configured to fix the respective sheave in a plurality of positions.

[0029] Optionally, for each sheave, the sheave system further comprises a sheave locking pin actuator configured to move the respective sheave locking pin into and out of the respective sheave holder.

[0030] An additional advantage of the invention is that the sheave system can be reconfigured or the sheaves can be repositioned remotely without the need for direct interaction between the operator and the locking pins. This improves the safety of the system, especially when deployed on a cable laying vessel that operates in harsh weather conditions.

[0031] Optionally, the first sheave and the second sheave each further comprise a sheave pulley locking pin, and the pulley further comprises a pulley holder, preferably two or more pulley holders. The pulley holder is a hole configured to receive a portion of the sheave pulley locking pin, and the pulley is configured to be fixed when the pulley holder receives the sheave pulley locking pin, preferably relative to one or more of the sheaves, more preferably relative to the sheaves.

[0032] An additional advantage of the invention is that the pulley can be used in multiple modes, for example, unfixed and fixed. The offloading system can be tailored to the operating conditions (for example, deep water operation or shallow water operation, type of elongated flexible article), ensuring more efficient operation.

[0033] Optionally, the first and second wheel guards each further comprise a wheel guard pulley locking pin actuator configured to move the respective wheel guard pulley locking pin into and out of the pulley retaining member.

[0034] An additional advantage of the present invention is that the laydown wheel system can be reconfigured remotely depending on the operating conditions, without the need for direct interaction between the operator and the wheel guard pulley locking pin. This improves the safety of the system, especially when deployed on cable laying vessels operating in harsh weather conditions.

[0035] Optionally, the laydown wheel system further comprises a friction brake comprising a brake shoe. Preferably, the friction brake is positioned adjacent to the pulley surface and is configured to move between a braking position and a non-braking position. The brake shoe is configured to interact with the pulley surface by exerting a radial force on the pulley surface when the brake shoe is in the braking position.

[0036] An advantage of the present invention is that the pulley can be kept in place while fixing the pulley relative to the wheel guard. This makes the fixing of the pulley more predictable and thus more efficient.

[0037] Preferably, the laydown wheel system further comprises a friction brake actuator configured to move the brake shoe between the braking position and the non-braking position.

[0038] Preferably, the first and second wheel guards abut the pulley and each further comprise: an inner slide bearing mounted on the wheel guard rim side abutting the pulley, respectively, preferably entirely along the circumference of the respective wheel guard rim side; and an outer slide bearing mounted on the wheel guard rim side distal from the pulley, respectively.

[0039] An additional advantage of the present invention is that lateral forces exerted by the elongate flexible article on the laydown wheel system are transmitted between the wheel guard and the pulley and between the wheel guard and the runner. Therefore, each different wheel can be made lighter and using less rigid and / or strong materials, facilitating the production and installation of the laydown wheel system.

[0040] Optionally, the unloading runner further comprises a runner flange protruding from the sliding surface, the runner flange being configured to ensure that the bending radius of the elongate flexible article is at least equal to the minimum bending radius when the elongate flexible article extends along the runner flange.

[0041] Preferably, the runner flange and the wheel guard flange are collectively configured to ensure that the bending radius of the elongate flexible article is at least equal to the minimum bending radius when the elongate flexible article extends along the runner flange and along the wheel guard flange, preferably when the wheel guard is in its respective shallow water position.

[0042] An additional advantage of the invention is that the elongated flexible article never bends beyond its minimum bend radius, resulting in a more reliable cable loading operation, requiring less restarts and less activity to repair the elongated flexible article.

[0043] The invention also provides a vessel for laying an elongated flexible article, the vessel comprising an unloading system according to the invention, characterized in that the vessel comprises a stern, and the vessel is configured to unload the elongated flexible article at the stern, the unloading chute being located partly outboard of the stern. Alternatively, the vessel is configured to unload the elongated flexible article onto a starboard beam or a port beam, wherein the unloading chute is located partly outboard of the respective beam.

[0044] The invention also provides a method of using an unloading system and / or a vessel according to the invention. Optionally, the method is characterized in that the first sheave is located in a first sheave deep water position, the second sheave is located in a second sheave deep water position, and the elongated flexible article is located between the first sheave flange and the second sheave flange. Preferably, the elongated flexible article rotates the sheave in a sheave rotation direction.

[0045] An advantage of the invention is that the elongated flexible article is unloaded with less friction when operated in deep water operations. This reduces the wear and tear of the cable and the unloading system both by the unloading operation. The unloading operation will be more efficient and the unloading chute will require less maintenance.

[0046] Optionally, the method is characterized in that the first sheave is located in a first sheave shallow water position, the second sheave is located in a second sheave shallow water position, and the elongated flexible article is located between the first sheave flange and the second sheave flange. Preferably, the sheave is stationary.

[0047] An advantage of the invention is that the elongated flexible article can use a larger portion of the unloading chute, in particular during shallow water operations. An additional advantage is that the friction experienced by the elongated flexible article against the sliding surface is similar to the friction against the sheave surface. Alignment and tension can be better controlled, which facilitates the unloading operation with less tangling, twisting and excessive bending.

[0048] Optionally, the method is characterized in that the first sheave is located in a first sheave free sliding position, the second sheave is located in a second sheave free sliding position, and the elongated flexible article is located in an unloading quadrant that slides over the unloading chute and the sheave.

[0049] An advantage of the invention is that the invention has multiple modes of operation, including a mode of operation in which a quadrant can be deployed, for example, when the sheaves are located in their respective sheave free sliding positions.

[0050] Optionally, the method is characterized in that the brake shoe is in the braking position, the first guard wheel is rotated to align the first guard wheel pulley locking pin with the pulley retaining member, and / or the second guard wheel is rotated to align the second guard wheel pulley locking pin with the pulley retaining member. If both guard wheels are rotated, the order in which the guard wheels are moved is not important.

[0051] An advantage of the invention is that the pulley can be kept in place while fixing the pulley relative to the guard wheels. This makes the fixing of the pulley more predictable and thus more efficient.

[0052] Optionally, the method is characterized in that the first guard wheel pulley locking pin is moved into the pulley retaining member and / or the second guard wheel pulley locking pin is moved into the pulley retaining member, the first guard wheel is moved into any one of the first guard wheel deep water position, the first guard wheel shallow water position and the first guard wheel free sliding position, and / or the second guard wheel is moved into any one of the second guard wheel deep water position, the second guard wheel shallow water position and the second guard wheel free sliding position. Preferably, the first guard wheel pulley locking pin and / or the second guard wheel pulley locking pin is moved into the pulley retaining member before the respective guard wheel is moved into its respective guard wheel position. The first guard wheel and the second guard wheel can be moved simultaneously; when moved simultaneously, both the first guard wheel and the second guard wheel can be moved into the corresponding respective guard wheel position, e.g. both the first guard wheel and the second guard wheel are moved into their respective guard wheel deep water position, guard wheel shallow water position or guard wheel free sliding position. BRIEF DESCRIPTION OF DRAWINGS

[0053] The invention will be further elucidated by the following description and drawings.

[0054] Figure 1 An isometric projection of a lay down system according to the invention is shown.

[0055] Figure 2A A top view of a lay down system according to the invention configured to operate in deep water is shown.

[0056] Figure 2B A top view of a lay down system according to the invention configured to operate in shallow water is shown.

[0057] Figure 2C A top view of a lay down system according to the invention configured to lay down an elongate flexible article using a sector is shown.

[0058] Figure 3A A side view of a lay down system according to the invention configured to operate in deep water is shown.

[0059] Figure 3B A side view of a lay down system according to the invention configured to operate in shallow water is shown.

[0060] Figure 3C A side view of an unloading system configured to unload an elongate flexible article using a sector according to the present invention is shown.

[0061] Figure 4 A side view of a vessel according to the present invention is shown. DETAILED DESCRIPTION

[0062] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting, in the drawings, the size of some of the elements can be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the invention.

[0063] Furthermore, the terms "first", "second", "third", etc. that are used in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. Such terms can be interchangeable under appropriate circumstances, and the embodiments of the invention can operate in other sequences than described or illustrated herein.

[0064] Furthermore, the terms "top", "bottom", "front", "back", "over", "under", and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein.

[0065] The term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, A and B are the only relevant components of the device, and that the device can also include one or more other components.

[0066] Figure 1 An isometric projection of a laydown wheel system of an unloading system according to the present invention is shown. The laydown wheel system 101 comprises a pulley 102 comprising a pulley axle 103 and a pulley surface 104, and having a pulley rotation direction r and a pulley radius s. The pulley axle 103 is positioned along a pulley axle direction a. The pulley 102 is configured to move rotationally around the pulley axle 103 along the pulley rotation direction r.

[0067] The laydown wheel system 101 further comprises a first guard wheel 105 having a radius equal to the pulley radius s and a second guard wheel 106 having a radius equal to the pulley radius s. The first and second guard wheels 105, 106 each comprise a guard wheel surface 107 and a guard wheel flange 108 extending radially from the guard wheel surface 107. The first and second guard wheels 105, 106 each have a guard wheel rotation direction r g , respectively a first guard wheel rotation direction r g1 and a second guard wheel rotation direction r g2 . The first and second guard wheels 105, 106 are positioned axially adjacent to the pulley 102, with the respective guard wheel rotation directions r g of the first and second guard wheels being in line with the pulley rotation direction r, with the first guard wheel 105 being located on the other side of the pulley 102 relative to the second guard wheel 106. The first and second guard wheels 105, 106 are configured to move rotationally around the pulley axle 103 along the respective guard wheel rotation directions r g , and to have a portion of the guard wheel surface 107 flush with the sliding surface.

[0068] The first and second guard wheel flanges 108 are each configured to ensure that the bend radius of the elongate flexible article is at least equal to the minimum bend radius when the elongate flexible article extends along the respective guard wheel flange 108. The first and second guard wheel flanges 108 each span a guard wheel flange arc 109 across approximately 1 / 3 of the circumference of their respective guard wheel, with the respective guard wheel flange arcs 109 each having a guard wheel flange arc midpoint 110.

[0069] The laydown wheel system 101 further comprises, for each guard wheel, an arc of circle guard wheel rack 111 having a guard wheel rack center, a guard wheel pinion 112, and a guard wheel motor 113. The guard wheel rack 111 is connected to the respective guard wheel on the guard wheel side away from the pulley 102. The guard wheel pinion 112 is driven by the respective guard wheel motor 113, and the guard wheel pinion 112 is in mesh with the respective guard wheel rack 111. The first and second guard wheels 105, 106 each further have a guard wheel center on the respective guard wheel center axis. The guard wheel rack center is on the respective guard wheel center axis.

[0070] The laydown wheel system 101 further comprises, for each guard wheel, a guard wheel locking pin, and the first and second guard wheels 105, 106 each further comprise a guard wheel holder 114, in particular a plurality of guard wheel holders. The guard wheel holder 114 is a hole configured to receive a portion of the respective guard wheel locking pin. The first and second guard wheels 105, 106 are configured to be fixed when the respective guard wheel holder 114 receives the respective guard wheel locking pin. The laydown wheel system 101 further comprises, for each guard wheel, a guard wheel locking pin actuator 115 configured to move the respective guard wheel locking pin into and out of the respective guard wheel holder 114.

[0071] The first and second guard wheels 105, 106 each further comprise a guard wheel pulley locking pin, and the pulley 102 further comprises a pulley keeper, which is a hole configured to receive a portion of the guard wheel pulley locking pin. The pulley 102 is configured to be secured when the pulley keeper receives the guard wheel pulley locking pin. The first and second guard wheels 105, 106 each further comprise a guard wheel pulley locking pin actuator 116, which is configured to move the respective guard wheel pulley locking pin into and out of the pulley keeper.

[0072] The laying wheel system 101 further comprises a friction brake 117, which comprises a brake shoe 118. The friction brake 117 is positioned adjacent to the pulley surface 104, and the brake shoe 118 is configured to move between a braking position and a non-braking position, and the brake shoe 118 is configured to interact with the pulley surface 104 by exerting a radial force on the pulley surface 104 when the brake shoe 118 is in the braking position. The laying wheel system 101 further comprises a friction brake actuator 119, which is configured to move the brake shoe 118 between the braking position and the non-braking position.

[0073] The first and second guard wheels 105, 106 abut the pulley 102, and the first and second guard wheels 105, 106 each further comprise an inner plain bearing mounted on the respective guard wheel rim side abutting the pulley 102 along the entire circumference of the respective guard wheel rim side, and an outer plain bearing 120 mounted on the guard wheel rim side away from the pulley 102.

[0074] Figure 2A 、 Figure 2B 、 Figure 2C 、 Figure 3A 、 Figure 3B 、 Figure 3C An unloading system for unloading elongate flexible articles according to the present invention is shown. The unloading system 201 comprises an unloading chute 202, which comprises a sliding surface 203 having a sliding direction d. The sliding surface 203 comprises through holes, which are referred to as wheel slots 204. The unloading system 201 further comprises a laying wheel system 101, which is shown in Figure 1 . More information is found in the description of Figure 1 . For the sake of clarity, in Figure 2A 、 Figure 2B 、 Figure 2C 、 Figure 3A 、 Figure 3B 、 Figure 3CSome of the corresponding reference numbers are repeated. The pulley axle direction a is transverse to the sliding direction d, and the pulley rotation direction r is in line with the sliding direction d. The pulley 102 is configured to have a portion of the pulley surface 104 flush with the sliding surface 203 and to partially fill the wheel groove 204. The first guard wheel 105 and the second guard wheel 106 are configured to have a portion of the guard wheel surface 107 flush with the sliding surface 203 and to partially fill the wheel groove 204.

[0075] The first guard wheel 105 and the second guard wheel 106 are each configured to move between a respective guard wheel deep water position, a respective guard wheel shallow water position, and a respective guard wheel free sliding position. When the respective guard wheel flange arc midpoint 110 is located at the guard wheel deep water position angle a (preferably, at the guard wheel rotation direction r g above the upright direction) the first guard wheel 105 and the second guard wheel 106 are located at their respective guard wheel deep water positions, and protrude along most of the respective guard wheel flange 108 of the guard wheel flange arc 109 through the wheel groove 204. When the respective guard wheel flange arc midpoint 110 is located at the guard wheel shallow water position angle b (preferably, at the guard wheel rotation direction r g opposite the upright direction) the first guard wheel 105 and the second guard wheel 106 are located at their respective guard wheel shallow water positions, and protrude along a small portion of the respective guard wheel flange 108 of the guard wheel flange arc 109 through the wheel groove 204. When the respective guard wheel flange arc midpoint 110 is located at the guard wheel free sliding position angle g (preferably, at the guard wheel rotation direction r g opposite the upright direction) the first guard wheel 105 and the second guard wheel 106 are located at their respective guard wheel free sliding positions, and do not protrude along any portion of the respective guard wheel flange 108 of the guard wheel flange arc 109 through the wheel groove 204.

[0076] The unloading chute 202 further comprises a chute flange 205 protruding from the sliding surface 203, the chute flange being configured to ensure that the bending radius of the elongated flexible article is at least equal to the minimum bending radius when the elongated flexible article extends along the chute flange 205. The chute flange 205 and the guard wheel flange 108 are collectively configured to ensure that the bending radius of the elongated flexible article is at least equal to the minimum bending radius when the elongated flexible article extends along the chute flange 205 and along the guard wheel flange 108 (e.g., when the first guard wheel 105 and the second guard wheel 106 are located at their respective guard wheel shallow water positions).

[0077] Figure 2A a top view of an unloading system configured to operate in deep water according to the present invention is shown, Figure 3A a side view of an unloading system configured to operate in deep water according to the present invention is shown. The first guard wheel 105 is located at the first guard wheel deep water position, and the second guard wheel 106 is located at the second guard wheel deep water position.

[0078] Figure 2B A top view of an unloading system according to the invention, configured for operation in shallow water, is shown. Figure 3B A side view of an unloading system according to the invention, configured for operation in shallow water, is shown. A first guard wheel 105 is located in the first guard wheel shallow water position, a second guard wheel 106 is located in the second guard wheel shallow water position, and a pulley 102 is fixed.

[0079] Figure 2C Figure 3a shows a top view of an unloading system according to the invention configured to unload an elongated flexible article using a fan-shaped body, and Figure 3c shows a side view of the same system. A first guard wheel 105 is in a free sliding position, and a second guard wheel 106 is in a free sliding position.

[0080] Figure 4 A side view of a vessel for laying elongated flexible articles according to the present invention is shown. Vessel 401 includes, for example... Figure 2A , Figure 2B , Figure 2C , Figure 3A , Figure 3B , Figure 3C The uninstallation system 201 is shown in the diagram. For more information, please refer to the description of these accompanying figures. For clarity, in... Figure 4 Some corresponding reference numerals are repeated above. Vessel 401 includes a stern 402, and vessel 401 is configured to unload elongated flexible articles at the stern 402. Unloading chute 202 is partially located on the outer side of the stern 402.

Claims

1. An unloading system for unloading an elongated flexible article, said elongated flexible article having a minimum bending radius, said unloading system comprising - an unloading chute (202) comprising a sliding surface (203) having a sliding direction (d), characterized in that - said sliding surface has a through hole called a wheel slot (204), - said unloading system further comprises a laying wheel system (101) comprising a pulley (102) comprising a pulley axle (103), a pulley surface (104) and a pulley rotation direction (r), - said pulley axle is positioned along a pulley axle direction (a) transverse to said sliding direction, - said pulley rotation direction is aligned with said sliding direction, - said pulley is configured to - move rotationally around said pulley axle along said pulley rotation direction, - have a portion of said pulley surface flush with said sliding surface and partially fill said wheel slot.

2. The unloading system according to claim 1, characterized in that - said pulley further has a pulley radius (s), - said laying wheel system further comprises - a first guard wheel (105) having a radius equal to said pulley radius, - a second guard wheel (106) having a radius equal to said pulley radius, - said first and second guard wheels each comprise - a guard wheel surface (107), - wheel rotation direction (r g ), - a guard wheel flange (108) extending radially from said guard wheel surface, - said first and second guard wheels are positioned axially adjacent to said pulley, wherein respective guard wheel rotation directions of said first and second guard wheels are aligned with said pulley rotation direction, wherein said first guard wheel is located on an opposite side of said pulley relative to said second guard wheel, - said first and second guard wheels are configured to - move rotationally around said pulley axle along respective guard wheel rotation directions, - have a portion of said guard wheel surface flush with said sliding surface and partially fill said wheel slot.

3. The offloading system of claim 2, wherein, said guard wheel flange of said first guard wheel and said guard wheel flange of said second guard wheel are each configured to ensure that said elongated flexible article bending radius is at least equal to said minimum bending radius when said elongated flexible article extends along said respective guard wheel flange.

4. The unloading system according to any one of claims 2 and 3, characterized in that - said guard wheel flange of said first guard wheel and said guard wheel flange of said second guard wheel each span a guard wheel flange arc (109) across approximately 1 / 3 of a circumference of their respective guard wheel, said respective guard wheel flange arcs each having a guard wheel flange arc midpoint (110), - said first and second guard wheels are each configured to move between at least two of a guard wheel deep water position, a guard wheel shallow water position and a guard wheel free sliding position, - said first and second guard wheels: - when the corresponding fender flange arc midpoint is at a fender deep water position angle (a), preferably 43° from vertical in the fender rotation direction, the first and second fenders are at their respective fender deep water positions and protrude through the wheel well along a majority of their respective fender flange arc, - when the corresponding fender flange arc midpoint is at a fender shallow water position angle (b), preferably 59° from vertical opposite the fender rotation direction, the first and second fenders are at their respective fender shallow water positions and protrude through the wheel well along a minority of their respective fender flange arc, - when the corresponding fender flange arc midpoint is at a fender free sliding position angle (g), preferably 90° from vertical opposite the fender rotation direction, the first and second fenders are at their respective fender free sliding positions and do not protrude through the wheel well along any portion of their respective fender flange arc.

5. The unloading system of any one of claims 2 to 4, wherein, - for each fender, the laying wheel system further comprises a fender locking pin and a fender locking pin actuator (115), and - the first and second fenders each further comprise a fender retainer (114), - the fender retainer is a hole configured to receive a portion of the corresponding fender locking pin, - the fender locking pin actuator is configured to move the corresponding fender locking pin into and out of the corresponding fender retainer, - the first and second fenders are configured to be secured when the corresponding fender retainer receives the corresponding fender locking pin.

6. The unloading system of any one of claims 2 to 5, wherein, - the first and second fenders each further comprise a fender pulley locking pin, - the pulley further comprises a pulley retainer, - the pulley retainer is a hole configured to receive a portion of the fender pulley locking pin, - the pulley is configured to be secured when the pulley retainer receives the fender pulley locking pin.

7. The offloading system of claim 6, wherein, the first and second fenders each further comprise a fender pulley locking pin actuator (116) configured to move the corresponding fender pulley locking pin into and out of the pulley retainer.

8. The unloading system of any one of claims 1 to 7, wherein, - the laying wheel system further comprises a friction brake (117) comprising a brake shoe (118), - the friction brake is positioned adjacent to the pulley surface, - the brake shoe is configured to move between a braking position and a non-braking position, - the brake shoe is configured to interact with the pulley surface by exerting a radial force on the pulley surface when the brake shoe is in the braking position.

9. The unloading system of any one of claims 2 to 8, wherein, - the first and second fenders abut the pulley, - the first guard wheel and the second guard wheel each further comprise - an inner slide bearing mounted on the guard wheel flange side along the entire circumference adjoining the respective guard wheel flange side of the sheave, - an outer slide bearing (120) mounted on the guard wheel flange side away from the sheave.

10. A vessel (401) for laying down an elongated flexible article, the vessel comprising an unloading system according to any one of claims 1 to 9, characterized in that - the vessel comprises a stern (402) and the vessel is configured to unload the elongated flexible article at the stern, - the unloading chute is located partly outside the stern.

11. A method of using an unloading system according to any one of claims 1 to 9 and / or a vessel according to claim 10.

12. The method according to claim 11, characterized in that - the first guard wheel is located in a guard wheel deep water position of the first guard wheel, - the second guard wheel is located in a guard wheel deep water position of the second guard wheel, - the elongated flexible article is located between the guard wheel flange of the first guard wheel and the guard wheel flange of the second guard wheel, - the elongated flexible article rotates the sheave in the sheave rotation direction.

13. The method according to claim 11, characterized in that - the first guard wheel is located in a guard wheel shallow water position of the first guard wheel, - the second guard wheel is located in a guard wheel shallow water position of the second guard wheel, - the elongated flexible article is located between the guard wheel flange of the first guard wheel and the guard wheel flange of the second guard wheel, - the sheave is stationary.

14. The method according to claim 11, characterized in that - the first guard wheel is located in a guard wheel free sliding position of the first guard wheel, - the second guard wheel is located in a guard wheel free sliding position of the second guard wheel, - the elongated flexible article is located in an unloading sector, - the unloading sector slides on the unloading chute and the sheave.

15. The method according to claim 11, characterized in that - the brake shoe is located in the braking position, - the first guard wheel is rotated to align the guard wheel sheave locking pin of the first guard wheel with the sheave holder, - the second guard wheel is rotated to align the guard wheel sheave locking pin of the second guard wheel with the sheave holder.

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