WO2022171257A1

WO2022171257A1 - A protection system for installing a flexible member

Info

Publication number: WO2022171257A1
Application number: PCT/DK2022/050024
Authority: WO
Inventors: Jimmi Glud THIMGAARD; Christian Sola Holberg; Mikkel Poulsen ROSENDAHL
Original assignee: National Oilwell Varco Denmark I/S
Priority date: 2021-02-11
Filing date: 2022-02-10
Publication date: 2022-08-18
Also published as: EP4292178A1

Abstract

Herein is described a protection system, device and method for installing a flexible member through an opening of a subsea structure (16a). The Protection system comprises a retaining portion (1) comprising a tube shaped wall having a spring arrangement. The spring arrangement comprises a strip shaped portion (3) formed by cut(s) (2) in the tube shaped wall and having a flexible portion and a root (3a) where it is rooted to the tube shaped wall and comprises an outwards facing retaining protuberance (23b). During instalment the flexible portions carrying a retaining protuberance may be pressed inwards, as it passes through the opening until the retaining portion engages with the opening in the subsea structure.

Description

A PROTECTION SYSTEM FOR INSTALLING A FLEXIBLE MEMBER TECHNICAL FIELD

The invention relates to a protection system and a device for installing a flexible member, such as a cable e.g. a power cable or a pipe through an opening of a subsea structure e.g. a pillar or monopile of an offshore generator, such as a generator associated to a wind turbine structure or another energy harvesting structure.

BACKGROUND ART

There are various practical situations in which a flexible elongate member such as a power cable, an umbilical, or a pipeline needs to be routed along the seabed to enter a support structure through an opening in it.

For example when collecting power from offshore wind driven turbine generators it is known to connect a power cable through an opening in a subsea foundation of the generator e.g. a monopile.

The cable is for example connected at one end at a hang-off within the support pillar, which is generally embedded in the seabed, to somewhere above the sea- level, and pass through an opening in a wall of the support pillar, somewhere below the sea-level closer to the seabed, from a connection point inside the support pillar, and the cable rest on the seabed outside of the support pillar. Because the cable outside of the support pillar is subjected to movement as a result of tides and weather, the cable is vulnerable to damage as a result of movement of that part of the cable which comes into contact with the edge of the opening. In particular, contact with the edge of the opening can cause the cable to be bent around a sufficiently small bend radius to cause damage.

US2020271263 describes a protection device for preventing damage to an elongate flexible member passing through an aperture of a subsea structure. The protection device has a body portion adapted to be inserted into the aperture in a first direction and has an internal passageway for allowing movement of an elongate flexible member there through. The body portion has at least one latching element pivotally mounted on the body portion. The latching element is for engaging an edge of the aperture to prevent removal of the body from the aperture in a second direction, opposite to the first direction, after insertion of the body into the aperture in the first direction, to prevent the elongate member from engaging the edge of the aperture.

EP2329174 describes a similar protection device.

US2019229505 describes a quick release cable pull-in system for securing a conduit in which is arranged a cable to the mouth of a J-Tube or other opening in a structure. The system includes a collar with a groove attached to the end of the conduit. A rotatable locking arm releasable engages the collar when a tapered nose cone is pulled into the J-Tube. The rotatable locking arm has a shoulder member that is biased downward into the interior of the cylindrical opening. According to one aspect, the shoulder member is downwardly biased by an elastomeric collar.

According to another aspect, the shoulder member is downwardly biased by a spring, by magnetic forces or other means.

DISCLOSURE OF INVENTION

An objective of the present invention is to provide a protection system, which provides a good protection for a flexible member, such as a cable, an umbilical or a pipeline both during installation through an opening of a subsea structure as well as after installation thereof.

In an embodiment, it is an objective to provide a protection system, which facilitates a simple and reliable installation, which may even be a diverless installation.

In an embodiment, it is an objective to provide a protection device, which is relatively cost effective and is simple to use.

These and other objects have been solved by the invention or embodiments thereof as defined in the claims or as described herein below.

It has been found that the invention or embodiments thereof have a number of additional advantages, which will be clear to the skilled person from the following description.

The phrase "outwards facing retaining protuberance " is herein used to mean that the retaining protuberance is facing outwards relative to the tube shaped wall and the passage formed thereby. The term "rigid" is herein used to mean that a rigid element is stiff at least at standard conditions of 1 atm. and 23 °C.

It should be emphasized that the term "comprises/comprising" when used herein is to be interpreted as an open term, i.e. it should be taken to specify the presence of specifically stated feature(s), such as element(s), unit(s), integer(s), step(s) component(s) and combination(s) thereof, but does not preclude the presence or addition of one or more other stated features.

Throughout the description or claims, the singular encompasses the plural unless otherwise specified or required by the context.

The "an embodiment" should be interpreted to include examples of the invention comprising the feature(s) of the mentioned embodiment.

The term "about" is generally used to include what is within measurement uncertainties. When used in ranges the term "about" should herein be taken to mean that what is within measurement uncertainties is included in the range.

The term "substantially" should herein be taken to mean that ordinary product variances and tolerances are comprised. All features of the invention and embodiments of the invention as described herein, including ranges and preferred ranges, may be combined in various ways within the scope of the invention, unless there are specific reasons not to combine such features.

Any chemical or physical property is to be determined at standard conditions of 23 °C and 1 atm. unless otherwise specified.

The protection system of the invention is adapted for being installed through an opening of a subsea structure for installing a flexible member through the opening.

Examples of subsea structures includes, monopoles, Gravity Base Structures, Jacket Structures and Tripod Structures.

The opening in the subsea structure may be any opening where it is desired to pull a length section of the protection system through, such that a length section is located inside the subsea structure and another length section is located outside the subsea structure. Thereafter a flexible member may be pulled through the passage in the protection system. The opening in the subsea structure may for example be a hole or aperture in the subsea structure, such as a hole or any kind of opening in a pillar or a monopile into a hollow portion of the pillar/monopile.

In an embodiment, the opening in the subsea structure is in the form of a passage through a guide tube, such as a J-tube or an I-tube.

In an embodiment, the subsea structure comprises a J-tube connection to a jacket- based wind turbines or a J-tube connections of a jacket-based substation, such as a transformer station.

The flexible member may for example be a cable, such as a power cable and/or a cable comprising optical fibre(s), a pipe such as a flexible bonded or unbonded pipe, an umbilical or any combination comprising one or more of these.

The protection system of the invention comprises one or more tubular portions comprising at least a retaining portion. The retaining portion comprises a tube shaped wall and as a retaining length, which is the axial length of the retaining portion. The tube shaped wall of the retaining portion comprises at least one spring arrangement comprising a retaining protuberance. This spring arrangement may also be referred to as the retaining spring arrangement. The retaining spring arrangement comprises a strip shaped portion formed by one or more cuts in the tube shaped wall of the retaining portion. The strip shaped portion comprises a flexible portion and a root where it is rooted to the tube shaped wall of the retaining portion. The term "root" designates a root line where the strip shaped portion is in one with and/or integral with the tube shaped wall of the retaining portion.

In an embodiment, the protection system consists of the retaining portion.

The strip shaped portion comprises the outwards facing retaining protuberance.

The subsea structure may conveniently be a subsea foundation. In an embodiment, the subsea structure comprises or consists of a guide tube, such as a J-tube or an I- tube and/or it may comprise or consist of a support pillar. The subsea structure may for example be a subsea foundation of an energy harvesting system comprising a generator e.g. a subsea foundation comprising a support pillar. The flexible portion is adapted for being pressed inwards to the passage of the retaining portion, i.e. the passage defined by the inwards facing surface of the retaining portion, to allow the retaining protuberance to pass into the opening of the subsea structure where after the flexible portion is released from the pressure and the retaining protuberance is engaged with a mating portion of the subsea structure to retain the retaining portion from unintentionally being retained from the opening of the subsea structure.

To ensure an effective and stable operation of the retaining portion, it is desired that the tube shaped wall of the retaining portion is substantially rigid against bends. And preferably also rigid for preventing unintended collapse of the retaining portion.

To provide a high and stable protection the retaining portion is advantageously substantially rigid against bends to maintain a substantially stationary axis, which may preferably be straight or it may be curved However, preferably the retaining portion is not too curved, such as more than 45 degrees, since such retaining portion with a highly curved axis may be more difficult to insert into the opening of the subsea structure than where the retaining portion has a less curved or straight axis.

Advantageously, the retaining portion except for the spring arrangement(s) is rigid.

The term "rigid" is herein used to mean that the rigid element is stiff at least at standard conditions of 1 atm. and 23 °C.

Advantageously the retaining portion at standard conditions has a flexural stiffness (bending stiffness) El of at least 100 kNm², such as at least about 500 kNm², preferably at least 1000 kNm².

The term "rigid" when applied for the retaining portion preferably mean that the retaining portion has a flexural stiffness El of at least 500 kNm².

In an embodiment, the retaining portion has a stiffness, such that a bend in axial direction below a minimum bend radius (MBR) will result in a plastic deformation and wherein MBR is 15 m, such as 10 m.

The tube shaped wall of the retaining portion may comprise one or more layers, such as one or more main layers extending in the entire tube shaped wall of the retaining portion and optionally one or more additional layers extending only in a part of the tube shaped wall of the retaining portion.

The tube shaped wall of the retaining portion may for example comprise a layer of a metal, such as steel. By providing the tube shaped wall of the retaining portion to be partly or fully of metal a very strong and durable retaining portion is obtained and in addition, the weight of the retaining portion may make it simpler to install the protection system. In addition, the weight of the metal of the retaining portion or of other parts of the protection system may contribute to less dynamic movement during service and/or operation, which may be highly beneficial in particular for large diameter protection systems.

In addition, the metal layer provides a high thermal conductivity, which reduces or even prevents risk of overheating of the flexible member housed in the protection system after installing. This may in particular be beneficial where the flexible member comprises a conductor, such as a high power conductor, for example a conductor arranged for transporting power from a generator.

In an embodiment, the tube shaped wall of the retaining portion may comprise or consist of one or more polymer layers. The one or more polymer layer may for example includes one or more fibre reinforced polymer and/or one or more non fibre reinforced polymer.

In an embodiment the fibre reinforced polymer comprises a cross-linked and/or a thermoset polymer, such as a cross-linked polyolefin and/or epoxy resin.

In an embodiment, the retaining portion is fully or partly of polymer such as of a cross-linked polymer, such as a polyurethane (PU) or a copolymer comprising PU.

In an embodiment, the retaining portion is fully or partly of fibre reinforced polymer, such as fibre reinforced polymer comprising a fibre reinforced thermoset polymer(s). Examples of suitable fibres of the fibre reinforced polymer includes fibres selected from glass fibres, basalt fibres, polypropylene fibres, carbon fibres, glass fibres, aramid fibres, steel fibres, polyethylene fibres, mineral fibres and/or mixtures comprising at least one of the foregoing fibres.

The fibre reinforced polymer advantageously comprise at least about 10 % by weight of fibres, such as from about 20 % to about 90 % by weight of fibres. Advantageous the material of the at least one layer of material of the tube shaped wall has a young's modulus of at least about 0.7 GPa, such as at least about 1 GPa, such as at least about 10 GPa. Where the layer of material is a metal, it may be desired that the metal has a young's modulus of at least about 10 GPa, such as at least about 100 GPa, such as at least about 190 GPa, such as at least about 200 GPa.

In an embodiment, the cut(s) may be slim cut(s) providing a pair of opposite cut faces that are facing each other and is immediately adjacent to each other, such as with a distance of less than 1 mm.

In an embodiment, the cut(s) may be slot cut(s) providing a pair of opposite cut faces that are facing each other and having a distance of at least 1 mm, such as up to 2 cm, such as 2 - 10 mm, e.g. 3-5 mm.

In an embodiment, the cut(s) may comprise a combination of slim cut(s) and slot cut(s).

The cut(s) in the tube shaped wall of the retaining portion providing the strip shaped portion may in an embodiment be provided substantially perpendicular to the centre axis of the retaining portion.

In an embodiment, the cut(s) in the tube shaped wall of the retaining portion providing the strip shaped portion has an angle to the center axis of the retaining portion such as an angle up to about 55 °, thereby providing the pair of opposite cut faces with inclination in respect of the centre axis of the retaining portion.

The cut(s) in the tube shaped wall of the retaining portion providing the strip shaped portion may for example have an angle to the center axis of the retaining portion of from 10° to 55°, such as in the range of from 15° to 45°.

To ensure that the strip shaped portion may be pressed downwards into the bore of the retaining portion, the angle of the cut (s) in the tube shaped wall of the retaining portion providing the strip shaped portion should advantageously be directed such that the outwards facing surface of the strip shaped portion has a smaller surface area than the inwards facing surface of the strip shaped portion. Where the inwards facing surface of the strip shaped portion is larger than the outwards facing surface of the strip shaped portion, the edge(s) of the tube shaped wall of the retaining portion bordering the strip shaped portion, may block the strip shaped portion from flexing outwards.

Especially, where the inwards facing surface of the strip shaped portion is larger than the outwards facing surface of the strip shaped portion + an optional distance or distances between pair of opposite cut faces, the edge(s) of the tube shaped wall of the retaining portion bordering the strip shaped portion, may block the strip shaped portion from flexing outwards.

By ensuring that the strip shaped portion is blocked from flexing outwards, an even more safe and durable retaining effect may be obtained.

The cuts, such as the cut slots in the tube shaped wall may be provided by several cuttings means, such as a jig saw or by laser cutting.

In an embodiment, the cuts in the tube shaped wall is made by water jet cutting. Water jet cutting has proven to provide excellent and accurate cuts.

In an embodiment the cuts in the tube shaped wall is made by plasma cutting. Plasma cutting is very efficient in particular for cutting in steel having large wall thickness. Plasma cutting may be used for cutting steel plates having a thickness up to 150 mm.

In an embodiment, the cuts in the tube shaped wall is provided by use of oxy-fuel cutting using oxygen and a fuel gas.

The use of oxy-fuel cutting is especially advantageously where the tube shaped wall is of or comprises metal such as steel, since it is both fast and very accurate. The cutting process may for example applying a mixture of oxygen and fuel gas to preheat the metal to its 'ignition' temperature (bright red heat), which for steel is usually in the range 700°C - 900°C, but well below its melting point. A jet of oxygen is then directed into the preheated area instigating a vigorous exothermic chemical reaction between the oxygen and the metal to form iron oxide or slag. The oxygen jet blows away the slag enabling the jet to pierce through the material and continue to cut through the material. It should be understood that the strip shaped portion formed by the one or more cuts surrounds the strip shaped portion except for the root where it remains connected to the remaining of the retaining portion. The strip shaped portion has a length extending from the root and along the flexible portion e.g. in a line parallel to the axis of the retaining portion. The length of the strip shaped portion is advantageously larger than its maximal width, such as larger than twice its maximal width. The maximal width of the strip shaped portion may advantageously be at the root of the strip shaped portion. The root width of the strip shaped portion may be selected to provide the desired flexing force of the flexible portion of the strip shaped portion - i.e. the flexing force required to flexing the flexible portion inwards, preferably without resulting in plastic deformation.

The cuts in the tube shaped wall may conveniently comprise a pair of cuts having an average distance less than their average length and optionally a cross cut crossing from one of the pair of cuts to the other one of the pair of cuts, such as at a first edge of the respective cuts. The root of the strip shaped portion will then be formed at the second ends of the pair of cuts and the cross cut will form a free edge of the flexible portion of the strip shaped portion. The flexible portion extends from the root to the free edge.

The cross cut may be straight or curved and in the same way the pair of cuts may individually of each other be straight or curved. In an embodiment, the pair of cuts are substantially equidistant cuts. In an embodiment, pair of cuts in the tube shaped wall are cuts following parallel lines, such as straight parallel lines or non-parallel lines, such as lines that are angled to each other e.g. to provide a more narrow free edge than the width of the root.

The strip shaped portion may be substantially rectangular, triangular symmetrical in an axis parallel to the axis of the retaining portion or non-symmetrical. It may have a periphery with sharp or rounded edges. In an embodiment, the cuts in the tube shaped wall comprises a pair of cuts which together with the root provides that the strip shaped portion is substantially triangular.

Advantageously, the one or more cuts in the tube shaped wall comprises a cross cut providing a free end of the strip shaped portion wherein the free end of the strip shaped portion forms part of the flexible portion. Conveniently, the strip shaped portion comprises a longitudinal strip shaped portion with its length oriented lengthwise relative to the retaining length.

In an embodiment, the flexible portion of the strip shaped portion is located proximally to the root of the strip shaped portion, i.e. the flexible portion is located closer to the opening of the subsea structure than the root immediately prior to inserting the retaining portion into the opening of the subsea structure.

Alternatively, the flexible portion of the strip shaped portion may be located distally to the root of the strip shaped portion.

Distal and proximal is seen from the subsea structure. Proximal is (or adapted to be) closer to or longest into opening of the subsea structure and distal is (or adapted to be) further from or shortest into the opening of the subsea structure.

For providing the strongest retaining effect it is desired that the flexible portion of the strip shaped portion is located proximally to the root of the strip shaped portion.

In an embodiment, the flexible portion of the strip shaped portion is located distally to the root of the strip shaped portion. In an embodiment, the strip shaped portion has a length and the flexible portion has a tip, such as a free end, e.g. provided by a free edge and the outwards facing retaining protuberance is located closer to the tip than to the root, preferably immediately adjacent to the tip.

As mentioned the tip of the strip shaped portion may be provided by the free end of the strip shaped portion.

The, shape, height and location of the retaining protuberance may advantageously be selected in dependence of the shape and size of the opening in the subsea structure and the force that the retaining portion is adapted to retain.

The height of the retaining protuberance is determined from the outwards surface of conveniently, the outwards facing retaining protuberance has a maximal protruding height which is sufficient to engage and lock with an edge of the subsea structure after having passes into the opening. At the same time the maximal protruding height conveniently is sufficiently low for allowing the retaining protuberance together with at least a part of the retaining portion comprising the retaining protuberance to pass into the opening while the flexible portion of the spring arrangement is pressed into the passage of the tube shaped wall, preferably without resulting in plastic deformation of the retaining protuberance and/or the strip shaped portion including its root.

Advantageously the height is 1-20 cm, such as 2-10 cm, such as 3-5 cm.

Advantageously, the outwards facing retaining protuberance has an inclined surface forming a ramp inclining from a low level ramp end to a high level ramp end, wherein the low level ramp end is proximal to the high level ramp end. Thereby the retaining portion may be easy to press or draw through the opening of the subsea structure, because the flexible portion will gradually be pressed downwards as the retaining portion passes into the opening with the low level ramp end heading the high level ramp end.

The high level is preferably the maximal protruding height.

In an embodiment, outwards facing retaining protuberance has an engagement side extending from high level ramp end and down towards the strip shaped portion, the engagement side is preferably in the form of an engagement edge, which forms a safe engagement after the retaining protuberance has passed through the opening of the subsea structure.

The engagement side/edge is preferably adapted to engage with the opening in the subsea structure and may be shaped to mate with an inner surface on an inside wall adjacent and along the periphery of the opening in the subsea structure

The outwards facing retaining protuberance may be provided by or comprise folds of the strip shaped portion. E.g. by folding back the strip shaped portion at its free edge, for example to have a triangular shape.

Advantageously, the outwards facing retaining protuberance is provided by or comprises a locking wedge which is conveniently fixed to the flexible portion of the strip shaped portion. The locking wedge may for example comprise a flange extending beyond the free end of the strip shaped portion, to thereby make a desired fixation. The retaining protuberance e.g. in the form of the wedge is also referred to as a lock dog. The lock dog is configured for locking the retaining portion to the subsea structure.

The locking wedge may preferably be fixed to the flexible portion of the strip shaped portion by one or more shear pins. The shear pin(s) may e.g. have a weakening line for breaking at a preselected load.

That enables disconnecting the locking wedge and thereby the retaining effect by deliberate overloading. The shear pin(s) may be broken by retracting the retaining portion from the opening of the subsea structure, whereby a pressure increasing the preselected load is applied towards the engagement side/edge of the locking wedge.

The shear pins advantageously has a preselected breaking load thereby enabling disconnecting the locking wedge by deliberate overloading.

The retaining portion may comprise as many retaining spring arrangements as desired. Advantageously, the retaining portion comprises at least two, such as three retaining spring arrangements, such as four retaining spring arrangements. For most protection systems two retaining spring arrangements is desired and may be sufficient to make the retaining effect very stable and balanced.

In an embodiment, the protection system comprises at least one bend limiter portion, wherein the bend limiter portion comprises a length of a bend restrictor and/or a bend stiffener.

A bend restrictor functions as a mechanical stop and limits the radius of curvature of a length section of the flexible member to be installed to a minimum value.

A bend stiffener reduces bending stresses and curvature of a length section of the flexible member to be installed to acceptable levels

In an embodiment, the at least one bend limiter portion comprises a bend limiter located distally to the retaining portion. The distally located bend limiter portion will usually not be drawn through the opening of the subsea structure but may remain outside the subsea structure and reducing or preventing overbending of the flexible member along a length thereof. In an embodiment, the at least one bend limiter portion comprises a bend limiter portion located proximally to the retaining portion. The bend limiter portion located proximally to the retaining portion, may advantageously be integral with or connected to the retaining portion prior to being inserted through the opening of the subsea structure. The proximally located bend limiter portion protects an installed flexible member at a section thereof which has been passes through the opening.

Advantageously, the protection system comprises at least one bend limiter portion located distally to the retaining portion and at least one bend limiter portion located proximally to the retaining portion.

The bend limiter portion may in principle have any length, preferably at least 0.5 m, such as from 1 to 50 m, such as from 5 to 30 m depending on the size and shape and location of the subsea structure.

In an embodiment, the at least one bend limiter portion comprises a continuous bend limiter portion passing through the retaining portion and extending both distally to the retaining portion and proximally to the retaining portion, thereby forming both a distally located bend limiter portion and a proximally located bend limiter portion.

The continuous bend limiter further has the function of protecting a flexible member from being damaged, during instalment and/or during disconnecting the locking wedge by deliberate overloading. The spring arrangement with the retaining protuberance will then during instalment being pressed into the passage of the retaining portion, which due to the continuous bend limiter bell be an annulus formed between the retaining member and the continuous bend limiter. During

The locking wedge may preferably be fixed to the flexible portion of the strip shaped portion by one or more shear pins. The shear pin(s) may e.g. have a weakening line for breaking at a preselected load. When disconnecting the locking wedge by deliberate overloading, the disconnected wedge will not be in risk of coming into contact with the flexible member due to the continuous bend limiter. The risk of damaging of the flexible member may thereby be highly reduced.

That enables disconnecting the locking wedge and thereby the retaining effect by The retaining portion may conveniently be connected to the continuous bend limiter portion at one or more location, preferably comprising at least one annular connection.

The retaining portion may for example be connected to the continuous bend limiter portion in at least one rigid connection, such as by welding. Thereby a very strong connection may be formed.

In an embodiment, the retaining portion is swivel connected to the continuous bend limiter portion to provide that the retaining portion is swivel about the continuous bend limiter. Thereby the retaining portion may be swivelled to a desired orientation without rotation of the continuous bend limiter. This may be very beneficial to provide a desired orientation of the retaining portion to thereby provide desired location(s) of the one or more outwards facing retaining protuberance(s). For example it may be desired that at least one outwards facing retaining protuberance is facing downwards and/or that outwards facing retaining protuberances are pairwise located symmetrically relative to a downwards facing location of the retaining portion, e.g. where the downwards facing location of the retaining portion and the symmetrically located outwards facing retaining protuberance are located along a common annular line.

In an embodiment, where the retaining portion has only one single spring arrangement and only one outwards facing retaining protuberances, it is specifically desired that the retaining portion is swivel connected to the continuous bend limiter portion to provide that the retaining portion may be swivelled to provide that the outwards facing retaining protuberance is facing downwards to thereby optimized the retaining strength.

The retaining portion may conveniently comprise one or more markings indicating the orientation e.g. visualizing the orientation of the retaining portion.

In an embodiment, the retaining portion comprises a body portion comprising the at least one spring arrangement and to provide that the spring arrangement with the retaining protuberance may be pressed into the annulus formed between the body portion and the continuous bend limiter, the annulus may preferably have a height determined in radial direction, which height is at least the height of the outwards facing retaining protuberance. Thereby the continuous bend limiter does not block or hinder the function of the spring arrangement.

In an embodiment, the retaining portion comprises a distal end portion, a proximal end portion and a body portion between the distal end portion and the proximal end portion and wherein the at least one spring arrangement is located at the body portion. To ensure an effective function of the spring arrangement the wherein the body portion may conveniently comprises an inner diameter, which is sufficiently large to allow the flexible portion of the at least one spring arrangement to be pressed into the passage of the tube shaped wall of the retaining portion without being blocked by the continuous bend limiter.

In an embodiment, the body portion of the retaining portion comprises an inner diameter, which is at least the outer diameter of the continuous bend limiter plus the maximal protruding height of the outwards facing retaining protuberance. Preferably the body portion comprises an inner radius, which is at least the outer radius of the continuous bend limiter plus the maximal protruding height of the outwards facing retaining protuberance.

The retaining portion may advantageously comprise a blocking flange located at the distal end portion thereof. Preferably the blocking flange extends radially beyond body portion of the retaining portion. The blocking flange may be as described elsewhere herein.

Advantageously, the retaining portion comprises a distal end portion, a proximal end portion and a body portion between the distal end portion and the proximal end portion, wherein the connection of the retaining portion to the continuous bend limiter portion comprises at least one connection located at the proximal portion of the retaining portion to the continuous bend limiter and/or at least one connection located at the proximal portion of the retaining portion to the continuous bend limiter.

The at least one bend limiter portion may conveniently comprise a tube shaped wall having a bend limiter length.

The bend limiter tube shaped wall may comprise a layer of a metal, such as steel and/or a layer of polymer, such as of fibre reinforced polymer. The material or materials may for example be as the material(s) as for the retaining portion described above.

The tube shaped wall of the bend limiter portion may comprise one or more layers, such as one or more main layers extending in the entire tube shaped wall of the bend limiter portion.

The tube shaped wall of the bend limiter portion may for example comprise a layer of a metal, such as steel. By providing the tube shaped wall of the bend limiter portion to be partly or fully of metal a very strong a durable bend limiter portion is obtained and in addition, the weight of the bend limiter portion may make it simpler to install the protection system at relative deep water where buoyancy effects may be large.

In addition, the metal layer provides a high thermal conductivity, which as mentioned above reduces or even prevents risk of overheating of the flexible member housed in the protection system after installing.

In an embodiment, the tube shaped wall of the bend limiter portion may comprise or consist of one or more polymer layers. The one or more polymer layer may for example includes one or more fibre reinforced polymer and/or one or more non fibre reinforced polymer.

In an embodiment, the bend limiter portion is fully or partly of polymer such as of a cross-linked polymer, such as a polyurethane (PU) or a copolymer comprising PU.

In an embodiment, the bend limiter portion is fully or partly of fibre reinforced polymer, such as fibre reinforced polymer comprising a fibre reinforced thermoset polymer(s). Examples of suitable fibres of the fibre reinforced polymer includes fibres selected from glass fibres, basalt fibres, polypropylene fibres, carbon fibres, glass fibres, aramid fibres, steel fibres, polyethylene fibres, mineral fibres and/or mixtures comprising at least one of the foregoing fibres.

The fibre reinforced polymer advantageously comprise at least about 10 % by weight of fibres, such as from about 20 % to about 90 % by weight of fibres. Advantageous the material of the at least one layer of material of the tube shaped wall has a young's modulus of at least about 0.7 GPa, such as at least about 1 GPa, such as at least about 10 GPa. Where the layer of material is a metal, it may be desired that the metal has a young's modulus of at least about 10 GPa, such as at least about 100 GPa, such as at least about 190 GPa, such as at least about 200 GPa

Advantageously, the at least one bend limiter portion comprises a tube shaped wall comprising a cut pattern comprising one or more through cuts through the bend limiter tube shaped wall. The cuts may be applied in any pattern that provides the desired bending stiffness and/or bending restriction.

In an embodiment, the cut pattern comprising at least one cut slot, wherein edges on respective sides of the cut are not touching each other when the bend limiter portion is in straight and unloaded condition. This means that a fraction of the material of the tube shaped wall of the bend limiter portion is removed when providing the cut slot(s).

Advantageously, the cut pattern is sufficient for allowing the bend limiter portion to bend with a selected bending radius, wherein the selected bending radius is from 0.5 to 25 m, such as from 2 to 10 m.

To ensure the desired bending stiffness it may be desired that the cut pattern comprises cut(s) extending in substantially the entire circumference of the tube shaped wall. The cut(s) extending in substantially the entire circumference may be in form of one or more helically cuts or in form of a plurality of offset cuts which together extends in the entire circumference.

Advantageously, the cut pattern comprising a meandering pattern, preferably extending partly or fully in the circumference of the metal wall.

In particular it is desired that the cut pattern comprises a helically meandering pattern, such as a helically meandering pattern having a trapezoid meandering pattern.

An isosceles trapezoid is a trapezoid where the base angles have the same measure. As a consequence the two legs are also of equal length and it has reflection symmetry. This is possible for acute trapezoids or right trapezoids (rectangles). Preferably the trapezoid shape of the trapezoid meandering pattern is an isosceles trapezoid shape forming protrusions with a narrow waist.

Preferably the helically meandering pattern has a pitch of from 2 cm to 1 m, such as from 4 cm to 0.5 m. The pitch is advantageously larger than the width of the trapezoid meandering pattern, such as up to 10 times the width of the trapezoid meandering pattern, such as from 2 times to 5 times the width of the trapezoid meandering pattern.

The trapezoid meandering pattern may conveniently have a width of from 0.5 to 30 cm, such as from 1 to 15 cm, such as from 2 to 8 cm.

The cut(s), such as slot cut(s) may be provided substantially perpendicular to the centre axis of the bend limiter portion (determined with the bend limiter portion in straight condition) or the cut(s), such as slot cut(s) may be provided with an angle to the centre axis of the bend limiter portion, such as an angle up to about 55 °·

To avoid that sections between of the tube shaped wall are displaced laterally e.g. to partly overlap, it may be advantageously to provide the bend limiter with slots in which the faces have an inclination in respect of the centre axis. In an embodiment at least one of the lines defining the faces has an angle with the centre axis in the range of 10° to 55°, such as in the range of 15° to 45°.

In an embodiment the cut(s) forms a repeated trapezoid pattern. A trapezoid consists of straight lines in which at least two of the lines meet with an angle which differs from 90°.

In an embodiment the cut(s) form a helical pattern in the tubular wall. A helical pattern in which the cut line is continuous may be produced in a relatively simple manner.

Depending on the size and diameter of the flexible member adapted to be housed in the bend limiter and the force the bend limiter is expected to resist, the thickness of the tube shaped wall may conveniently be selected to be in the range of 1 to 80 mm, such as in the range of 3 to 50 mm, conveniently in the range of 5 to 30 mm.

In an embodiment, the at least one bend limiter portion is connected to the retaining portion optionally via an intermediate portion. In an embodiment, the at least one bend limiter portion is integrated with the retaining portion, preferably the at least one bend limiter portion and the retaining portion comprises respective sections of a common tubular, which advantageously has been provided by the cuts and retaining protuberance(s) as describes elsewhere herein.

Preferably, the protection system comprises at least two bend limiter portion, including at least one bend limiter portion integrated with the retaining portion and at least one bend limiter portion connected to the retaining portion e.g. via another bend limiter portion.

In an embodiment, at least one of the retaining portion and the one or more bend limiter portions comprises an internal wear coating, such as an anti-friction and/or bearing coating. The wear coating may for example be a polymer or a polymer containing composition, such as a coating comprising one or more of polyurethane (PU), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF), e.g. in a thickness of from 5 pm to 5 mm, such as from 10 pm to 1 mm, such as from 25 pm to 0.1 mm.

The wear coating is advantageously sprayed or painted on internal side of the portion or portions in question.

One or more of the at least one of the bend limiter portions may advantageously comprise an external polymer tube extending in at least a part of the length of the bend limiter portion, this external polymer tube may serve to adjust or increase the bend limiting effect and strength.

In an embodiment, at least one of the retaining portion and the one or more bend limiter portions and/or one or more intermediate portions is lined with an internal polymer tube arranged inside the portion or portions, the internal polymer tube may advantageously have a thickness of 0.5 mm to 5 cm, such as from 1 to 10 mm.

In an embodiment, at least one of the bend limiter portion(s) comprises an internal polymer tube extending in at least a part of the length of the bend limiter portion.

Where the protection system comprises an internal polymer tube located inside and lining the retaining portion, care should advantageously be taken to ensure that the internal polymer tube does not prevent the inwards flexing of the spring arrangement(s). This may e.g. be ensured by cutting openings in the internal polymer tube corresponding to the location(s) of the spring arrangement(s).

The protection system may comprise individual internal polymer tubes in the respective portions (the retaining portion and the one or more bend limiter portions and/or an intermediate portion) or one single internal polymer tube may extend inside two or more of the portions.

The internal polymer tube may serve to fill out space between a bend limiter portion and a flexible member to be installed to ensure an effective bend limiting effect.

In addition, the internal polymer tube may serve to reduce wear and/or to protect the flexible member to be installed.

The internal polymer tube may for example comprise one or more of the polymers olefin(s) such as polyethylene (PE) or polypropylene (PP), styrene, polyamid (PA) polyurethane (PU), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF).

To protect against corrosion e.g. of metal of the protection system or of parts adapted to be located close to the protection system, the protection system may beneficially comprise at least one offer anode. The offer anode may be attached to any part of the protection system. Advantageously the protection system comprises at least one offer anode attached to the retaining portion, the at least one bend limiter portion and/or an intermediate portion and wherein at least a part of the offer anode preferably protrudes outwards from the portion(s) to which it is attached.

In an embodiment, the offer anode is attached to a strip shaped flexible portion of an offer anode spring arrangement located on a tubular portion of the protection system, wherein the tubular portion defines a passage and the strip shaped flexible portion of the offer anode spring arrangement is configured for being pressed inwards to the passage of the tubular portion to allow the offer anode to pass into the opening of the subsea structure where after having passes the opening, the strip shaped flexible portion of the offer anode spring arrangement returns to its non- pressed stage. The offer anode spring arrangement may be shaped as the spring arrangement comprising the retaining protuberance, but carrying the anode instead of the retaining protuberance.

Where the, strip shaped portion of the offer anode spring arrangement should be capable of flexing both inwards and thereafter outwards to ensure space of a large offer anode, care should be taken to provide the cut(s) forming the strip shaped portion of the offer anode spring arrangement perpendicular to the centre axis of the portion comprising the offer anode spring arrangement or with an angle which ensures that the strip shaped portion of the offer anode spring arrangement is not blocked from flexing inwards or outwards.

By locating the anode on the flexible portion of the offer anode spring arrangement a relative large anode may be applied while still being simple to pull through the opening of the subsea structure. The flexible portion carrying the anode is pressed inwards during the passage through the opening of the subsea structure, where after it is returned to its initial position whereby the offer anode is located inside the subsea structure and at least a portion of the anode is located on the outside of the protection system.

In an embodiment, where the offer anode is attached to a tubular portion of the protection system, a piece of material is cut from the tubular portion and the offer anode being located to at least partly fill out the space left by cutting out the material piece.

The offer anode may be of any suitable material(s), such as at least one of zinc aluminium and/or indium or a material comprising one or more of these.

To prevent the protection system from being pulled too far into the opening of the subsea structure, the protection system may comprise a blocking flange located distally to the spring arrangement(s) of the retaining portion and extending radially beyond the periphery of the tube shaped wall of the retaining portion and preferably extending radially beyond the opening of the subsea structure to which the protection system is adapted to be installed.

The blocking flange may for example comprise a blocking collar. The blocking collar is advantageously located distally at the retaining portion or it may be located on an intermediate portion located between the retaining portion and a bend limiter portion.

The blocking flange has the function of preventing the protection system or the tubular portions from being pulled too far into the opening of the subsea structure and thereby ensures a simpler and less wear affecting installing of the flexible member through the opening of the subsea structure. In addition the locking flange may serve to provide resistance during a process of deliberating overloading the shear pins connecting the pull-in head to the retaining portion for disconnecting the pull-in head.

For pulling the protection system into and partly through the opening of the subsea structure, the protection system may beneficially comprises a proximally located pull- in head attached to or attachable to the retaining portion, optionally via one or more other tube shaped portion(s) of the protection system located proximally to the retaining portion.

The pull-in head may be attached to or attachable to the retaining portion via a bend limiter portion.

Advantageously, the pull-in head is attached to or attachable to the retaining portion through shear pin(s) that enable disconnecting the pull-in head from the retaining by deliberate overloading. The deliberate overloading may for example be provided by exerting a high pull load in the pull-in head, such that the blocking collar is pressed towards the wall surrounding the periphery of the opening to resist further pulling in. This may make the shear pins break and release the pull-in head from the remaining portions of the protection system.

As explained above the protection system may comprise a plurality of tubular portions including the retaining portion and the optional one or more bend limiter portions and/or the optional one or more intermediate portions, which portions is aligned to provide a passage for a flexible member to be installed.

In an embodiment, at least one of the retaining portion and the one or more bend limiter portions and/or one or more intermediate portions is/are covered with an external polymer tube arranged outside the portion or portions, the external polymer tube may advantageously have a thickness of 0.5 mm to 10 cm, such as from 1 to 3 cm, such as from 2 to 10 mm.

Where the protection system comprises an external polymer tube located outside the retaining portion, care should advantageously be taken to ensure that the external polymer tube is provided with openings/holes for the retaining protuberance and the retaining protuberance should protrude beyond the external polymer tube when the arrangement is in unloaded condition.

The retaining portion is advantageously not covered by an external polymer tube.

Advantageously, the one or more bend limiter portions is/are covered with the one or more external polymer tube to increase the effect of the bend limiter portion(s).

The external polymer tube may for example comprise one or more of the polymers olefin(s) such as polyethylene (PE) or polypropylene (PP), styrene, polyamid (PA) polyurethane (PU), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF).

The invention also comprises a protection device for installing a flexible member through an opening of a subsea structure. The protection device comprise at least a retaining portion, wherein the retaining portion comprises at least one spring arrangement and the at least one bend limiter portion comprises cut pattern comprising one or more through cuts through a wall of the steel tubular. The retaining member of the device may be as described above for the retaining protection system.

Advantageously, the a protection device for installing a flexible member through an opening of a subsea structure comprises tubular having a length and comprising a plurality of tubular portions including the at least a retaining portion and at least one bend limiter portion, wherein the retaining portion comprises at least one spring arrangement and the at least one bend limiter portion comprises cut pattern comprising one or more through cuts through a wall of the steel tubular.

The protection device advantageously comprises a plurality of portions, such as the portions described above including at least the retaining portion and preferably the one or more bend limiter portion in one single unit has shown to be very beneficial in many respects including simple use and installing, high strength and stability. In addition the protection device is economically feasible.

The plurality of tubular portions comprising at least the retaining portion and the bend limiter portion comprises same material or materials, such as a layered structure of materials, and preferably comprises one layer of a metal and/or a polymer, such as a fibre reinforced polymer extending in the entire length of the tubular, preferably the tubular comprises a layer of steel in its entire length.

In an embodiment, the plurality of tubular portions comprising at least the retaining portion and the bend limiter portion comprises identical material or materials, such as a layered material except for local elements such as the retaining protuberance and optional offer anodes which may be of different materials.

The protection device may comprise any of the tubular portions as described above, such as a plurality of tubular portions including the retaining portion and one or more bend limiter portions and/or one or more intermediate portions, which portions provide a passage for a flexible member to be installed.

In an embodiment, the protection device is or forms part of the protection system as described above.

In an embodiment, the protection device comprises the retaining portion and a continuous bend limiter passing through the retaining portion and extending both distally to the retaining portion and proximally to the retaining portion as described above for the protection system.

The retaining spring arrangement comprises a strip shaped portion formed by cuts in the tube shaped wall forming a passage, wherein the strip shaped portion having a flexible portion and a root where it is rooted to the tube shaped wall of the retaining portion and comprises an outwards facing retaining protuberance adapted for engaging with the subsea structure.

The bend limiter portion(s), the retaining spring arrangement, the retaining protuberance and the optional anode and anode spring arrangement may advantageously be as described above for the system.

In an embodiment, the plurality of tubular portions comprising at least the retaining portion and the bend limiter portion are of same material or materials, such as a layered structure of materials, and preferably comprises one layer of a metal and/or a polymer, such as a fibre reinforced polymer extending in the entire length of the tubular, preferably the tubular comprises a layer of metal, preferably steel in its entire length.

The material(s) may advantageously be as described above

The metal layer provides the protection device with high strength and a high thermal conductivity. In addition the retaining spring arrangement(s) and optional anode spring arrangement(s) with a desired spring force may conveniently be of same material or materials, such as a layered structure of materials, and preferably comprises one layer of a metal and/or a polymer, such as a fibre reinforced polymer extending in the entire length of the tubular, preferably the tubular comprises a layer of steel in its entire length.

The invention also comprises a method of installing a flexible member in a subsea structure using a protection system as described above and/or a protection device as described above. The method comprising pulling the flexible member through an opening in the subsea structure. The method comprises

- inserting the flexible member through a tubular comprising at least the retaining portion of the protection system and/or protection device as described herein and defined in the claims and mounting an end portion of the flexible member to a pull-in head;

- attaching the pull-in head to the retaining portion optionally via another tubular portion of the tubular proximally located to the retaining portion, such as the bend limiter portion;

- pulling the pull-in head and at least a part of the retaining portion comprising the one or more flexible portions carrying a retaining protuberance through the opening, until the retaining portion engages with the opening in the subsea structure;

- Releasing the pull-in head from the tubular and pulling the flexible member further into the structure to its final position.

Advantageously, the pulling in of least a part of the retaining comprising the one or more flexible portions carrying a retaining protuberance through the opening results in pressing the flexible portion downwards to allow the retaining protuberance passing into the opening where after when the retaining protuberance has passed fully through the opening or a narrower portion thereof, the downwards pressure of the flexible portion is released and the retaining protuberance engages with the opening in the subsea structure to form an obstacle preventing the retaining portion from retract backwards through the opening.

All features of the inventions and embodiments of the invention as described herein including ranges and preferred ranges may be combined in various ways within the scope of the invention, unless there are specific reasons not to combine such features.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS AND ELEMENTS OF THE INVENTION

The above and/or additional objects, features and advantages of the present invention will be further elucidated by the following illustrative and non-limiting description of embodiments of the present invention, with reference to the appended drawings.

The figures are schematic and are not drawn to scale and may be simplified for clarity. Throughout, the same reference numerals are used for identical or corresponding parts.

Figure 1 illustrates a side view of an embodiment of a protection system of the invention.

Figure 2 is a perspective illustration of an installed embodiment of a protection system, where the protection system has been installed in a monopile.

Figure 3 is a close up perspective illustration of another installed embodiment of a protection system, where the protection system has been installed in a monopile.

Figures 4a and 4b are perspective views of a retaining portion of an embodiment of a protection system of the invention.

Figure 5a is perspective view of a retaining portion of an embodiment of a protection system of the invention, wherein the retaining protuberance has not yet been mounted or where it has been removed. Figure 5b is perspective view of a section of the retaining portion of figure 5a, with a mounted retaining portion in the form of a locking wedge, also referred to as a lock dog.

Figure 6a is perspective view of a retaining portion of an embodiment of a protection system of the invention, wherein the spring arrangement has been provided in the form of a strip shaped cut portion.

Figure 6b shows the retaining portion of figure 6a wherein the strip shaped portion has been folded to provide a retaining protuberance.

Figure 6c is a cross-sectional view of the retaining portion of figure 6b seen in the line marked A-A.

Figure 7a is a length wise cross-sectional view of a retaining portion taken through a strip shaped portion of the retaining portion prior to folding the strip shaped portion prior to folding the strip shaped portion to provide a retaining protuberance.

Figure 7b is a length wise cross-sectional view of the retaining portion of figure 7a taken through the strip shaped portion after the strip shaped portion has been folded to provide the retaining protuberance.

Figure 8 is a side view of the bend limiter portion of an embodiment of a protection system of the invention.

Figure 9 is a close op view of cuts of a bend limiter portion of an embodiment of a protection system of the invention.

Figure 10 is a perspective illustration of an embodiment of a proximally located pull- in head attached to an embodiment of a protection system of the invention.

Figure 11a is schematic cross sectional view of a length of an embodiment of a protection system of the invention comprising an offer anode mounted to an offer anode spring arrangement located at the retaining portion or proximally to the retaining portion before the protection system has been installed through an opening of a subsea structure.

Figure lib is a side view of the length the protection system shown in figure 11a. Figure 11c is schematic cross sectional view of the length the protection system shown in figure 11a, during installation of the protection system through an opening of a subsea structure.

Figure lid is schematic cross sectional view of the length the protection system shown in figure 11a, during or after installation of a flexible member in the protection system.

Figures 12a and 12b are perspective views of a retaining portion of an embodiment of a protection system of the invention.

Figure 13 is a schematic illustration of an installed embodiment of a protection device, where the protection device has been installed through an opening of a schematically illustrated subsea structure.

The protection system illustrated in figure 1 comprises a retaining portion 1 in the form of a length section of the protection system. The retaining portion 1 comprises a tube shaped wall and having a retaining length as illustrated between a distally located bend limiter portion 5 and a proximally located bend limiter portion 4. The retaining portion 1 comprises a spring arrangement also referred to as a retaining spring arrangements formed by a strip shaped portion 3 formed by one or more cuts 2 in the tube shaped wall of the retaining portion 1. The strip shaped portion 3 has a flexible portion and a root 3a where it is rooted to the tube shaped wall of the retaining portion 1. The dashed line shows the width of the root, which in this embodiment is equal to the width of the strip shaped portion 3. At the flexible portion of the strip shaped portion 3, it has a through hole 3b for mounting a lock dog, preferably by a shear pin.

Distally to the retaining spring arrangements and the root 3a of the flexible portion the retaining portion comprises an offer anode 8.

It should be understood that offer anodes may be located at any portions of the protection system.

The proximally located bend limiter portion 4 is integrated with the retaining portion 1 and is of same material e.g. as the material(s) described above. The bend limiter portion 4 is provided by tube shaped wall comprising a cut pattern comprising one or more through cuts as described above through the bend limiter tube shaped wall to provide the bend limiter portion with the desired stiffness and/or minimum bending restriction.

Proximally to the cut pattern a pull-in head 7 (also called a pull-head) attached to or the distally located bend limiter portion 4 and thereby also attached to the retaining portion 1. The pull-in head 7 is attached to the distally located bend limiter portion 4 by one or more shear pins 7a. The shear pin(s) may preferably have a preselected strength e.g. provided by a weakening line in the shear pin, such that the shear pin may break by deliberate overloading and releasing the pull-in head 7 from the distally located bend limiter portion 4.

In the shown embodiment the distally located bend limiter portion 5 is also integrated with the retaining portion 1 and is of same material e.g. as the material(s) described above. The bend limiter portion 5 is provided by tube shaped wall comprising a cut pattern comprising one or more through cuts as described above through the bend limiter tube shaped wall to provide the bend limiter portion with the desired stiffness and/or minimum bending restriction. The distally located bend limiter portion 5 and the proximally located bend limiter portion may be equal or different, for example the cut pattern may differ to provide a difference in bend limiting effects, such as a difference in minimum bending radius.

The pull-in head 7 is connected to a flexible member 9, which is partly pulled into the protection system. The pull-in head 7 may for example be connected to the flexible member by a not shown rope, such as a braided rope fastened to the flexible member according to the Chinese finger trap principle.

During the installation of the protection system the flexible member 9 is only pulled into the parts of the protection system located distally to the retaining spring arrangements and the root 3a of the flexible portion the retaining portion to ensure free operation of the retaining spring arrangements during instalment of the protection system. Advantageously the flexible member 9 is only pulled into the parts of the protection system located distally to retaining portion 1. An internal polymer tube 9a is located between the flexible member 9 and one or more of the portions of the protection system including the distally located bend limiter portion 5.

The protection system 10 shown in figure 2, is installed in a monopole where the protection system has been installed through an opening 16b in a subsea structure which in this embodiment is a monopole 16a. The top part of the monopole 16a is not shown but may for example provide a support for a generator, such as a generator associated to a wind turbine or a wave power farm. The monopole is fixed at the seabed S, e.g. by being partly buried therein.

The protection system comprises from its proximal end to its distal end a proximally located bend limiter portion 14 a retaining portion 11, a first distally located bend limiter portion 15a and a second distally located bend limiter portion 15b, wherein the first distally located bend limiter portion 15a and the second distally located bend limiter portion 15b are connected to each other at connection flanges 15c of the respective distally located bend limiter portions. The connection flanges 15c, may for example be connected using not shown screws and bolts.

The retaining portion 11 comprises a not shown retaining spring arrangement which may be located at its downwards facing tube shaped wall. The spring arrangement comprises a strip shaped portion formed by one or more cuts in the tube shaped wall of the retaining portion 11, wherein the strip shaped portion having a flexible portion and a root where it is rooted to the tube shaped wall of the retaining portion 11 and further the flexible portion comprises an outwards facing retaining protuberance e. g. as described elsewhere herein for example as in figure 4a and 4b. The retaining protuberance is located inside the opening 16b and thereby inside the monopole 16a and has the function of retaining the protection system from passing backwards out of the opening 16a of the monopole 16b.

The retaining portion 11 further comprises a blocking flange 11a located distally to the not shown spring arrangement of the retaining portion and is located outside the opening 16b of the monopole 16a. The blocking flange 11a extends radially beyond the periphery of the tube shaped wall of the retaining portion 11 and also extending radially beyond the opening 16b of the monopole 16a, such that it is unable to be passed through the opening 16b and thereby is functioning as the blocking flange it is.

The protection system further comprises a number of offer anodes 18a, 18b which in principle may be located at any location. Due to the required or desires size of offer anodes, it may be difficult to arrange the offer anodes proximally to the spring arrangement(s) of the retaining portion 11. As described elsewhere herein this problem may be solved by locating the offer anodes offer anode spring arrangements. However in this embodiment the protection system comprises offer anodes 18a located at the first distally located bend limiter portion 15a and offer anodes 18b located at the second distally located bend limiter portion 15b.

A flexible member 19 mounted to a not shown proximally located pull-in head has been pulled through the protection system.

At the time of mounting the protection system 10 through the opening 16b of the monopole 16a the pull-in head would conveniently have been fixed at the proximal end of the protection system 10. After having pulled the outwards facing retaining protuberance of the spring arrangement through the opening 16b, the protection system has been pulled further until the blocking flange 11a was pressed towards the wall at the periphery of the opening 16b, and a sufficient load to break the shear pins fixing the pull-in head to the protection system 10 was provided.

Thereafter the flexible member is being pulled further through the protection system 10, until it reaches a desired location inside the monopole 16a.

In figure 3 only a part of the protection system in the form of a protection device is seen as it is passed through the opening 26b of the monopole 26a. The monopole 26a is located at the seabed S and is seen in a cross-sectional view. The protection system comprises from its proximal end to its distal end a proximally located bend limiter portion 24 a retaining portion 21 and a distally located bend limiter portion 25.

The retaining portion 21 comprises a number of retaining spring arrangements 23 located at its tube shaped wall. The spring arrangement comprises a strip shaped portion 23a formed by one or more cuts in the tube shaped wall of the retaining portion 21. As seen the flexible portion 23a is located proximally to its root and a portion of the tube shaped wall proximally to the flexible portion is cut out. A lock dog comprising a retaining protuberance 23b is located at the flexible portion 23a of the retaining spring arrangements 23.

The retaining portion 21 further comprises a blocking flange 21a located distally to the spring arrangement 23 of the retaining portion 11 and is located outside the opening 26b of the monopole 26a.

The protection system further comprises a number of offer anodes 28, which as shown may be relatively large to ensure a desired galvanic protection.

Figures 4a and 4b show respective perspective views of the same retaining portion 31.

The retaining portion 31 comprises a number of retaining spring arrangements located at its tube shaped wall. The spring arrangement comprises a strip shaped portion 33a formed by one or more cuts 32 in the tube shaped wall of the retaining portion 31. A portion of the tube shaped wall proximally to the flexible portion is cut out to form a window 33d. A lock dog 33b (also called a locking wedge) comprising a retaining protuberance is mounted to the strip shaped portion 33a to form the retaining protuberance and is further passing through the window 33d to fully cover an otherwise free edge of the strip shaped portion 33a. Each lock dog 33b is mounted to respective strip shaped portion 33a by one or more shear pin 33c. As shown on figure 4a the retaining portion 31 also comprises a blocking flange 31a.

The outwards facing retaining protuberance of the lock dog 33b has an inclined surface forming a ramp inclining from a low level ramp end to a high level ramp end where an engagement edge 33e is formed at the high level ramp end. The engagement edge 33e. When the protection system with the retaining portion 31 is installed through an opening of a subsea structure, the proximal end of the protection system is pulled through the opening including a part of the retaining portion 31. As the lock dog 33b is pulled through the opening the ramp inclining from a low level ramp end to a high level ensures a gradually increasing force against the flexible portion 33a that presses the flexible portion 33a and the lock dog 33b, until the engagement edge 33e has passed through, where after the load is released and the flexible portion 33a, flexes back to its original position. The engagement edge 33e will now protrude beyond the periphery of the opening of the subsea structure and ensure that the part of the protection system located proximally to the retaining protuberance will not be undeliberately retracted from the opening of the subsea structure.

The shear pins 33c may comprise a weakening line for breaking at a preselected load, e.g. as described above.

Figures 5a and 5b show respective perspective views of sections the same retaining portion 41, wherein parts have been omitted.

The retaining portion 41 comprises a number of - in this embodiment three - retaining spring arrangements located in the circumference of its tube shaped wall. The spring arrangement comprises a strip shaped portion 43a formed by one or more cuts 42 in the tube shaped wall of the retaining portion 41 and comprising a flexible portion 43a and a root 43r. A portion of the tube shaped wall proximally to the flexible portion 43a is cut out to form a window 43d. In figure 5a, the retaining portion 41 is shown without a lock dog. A mounting hole 43c for mounting a lock dog is located at the flexible portion 43a.

In figure 5b, the retaining portion is shown with lock dogs 43b mounted to the retaining spring arrangements, whereas the spring arrangements facing forwards in the figure is without a lock dog. One of the log dogs 43b is seen from the side and it can be seen that it has an engagement edge 43e for being engaged with an edge of an opening of a subsea structure. The other one of the log dogs 43f is seen through the window 43d of the spring arrangements that is facing forwards without a lock dog. Here it can be seen that the lock dog form an extension of or extend beyond the otherwise free end of the strip shaped portion and covers a part of the inwards surface of the strip shaped portion.

Figures 6a-6c show a retaining portion 51 comprising a retaining spring arrangements provided by a strip shaped portion formed by one or more cuts 52 in the tube shaped wall 51b of the retaining portion 51. The strip shaped portion comprises a flexible portion 53a and a root 53r. The flexible portion 53a has a free end 53f. In figure 6a, the flexible portion 53a is in unfolded condition. In figures 6b and 6c the flexible portion 53a is folded from its free end 53f to form the retaining protuberance 53b. The free end 53f of the flexible portion 53a is welded in weld 53w to the wall of the flexible portion at a distance from its root 53r to enhance the strength of the retaining protuberance 53b. The folding to the flexible portion 53a to form the retaining protuberance 53b, provides a window 53d which ensure an unhindered flexing of the flexible portion 53a.

Figures 7a-7b illustrate a length wise cross-sectional view of a retaining portion which is a variation of the retaining portion 51 illustrated in figure 6a-6c.

The retaining portion comprises a retaining spring arrangements provided by a strip shaped portion formed by one or more cuts in the tube shaped wall 51b of the retaining portion. The strip shaped portion comprises a flexible portion 53a and a root. In figure 7a, the flexible portion 53a is in unfolded condition. In figures 7b the flexible portion 53a is folded from its free end to form the retaining protuberance 53b. The retaining protuberance 53b is formed with an inclined surface forming a ramp inclining from a low level ramp end to a high level ramp end, to thereby provide an engagement edge extending from the high level ramp end and down to the strip shaped portion.

Figure 8 show an example of a bend limiter portion 60 suitable for embodiments of the protection system or the protection device of the invention. The bend limiter portion 60 is of a rigid material and comprises a cut pattern 61 in the form of a helically meandering pattern having a desired pitch 62. The bend limiter portion 60 may be integrated with the retaining portion of a protection device or it may be connectable to a portion such as a retaining portion or another bend limiter portion of the protection system.

Figure 9 show the shape of the meandering cut in more detail. The meandering cut has a trapezoid meandering shape with a height h, a platform p, a width w, a slope s, a radius r and a pitch 62 as shown in figure 8. A desired flexibility and/or minimum bending radius of the bend limiter portion 61 may be designed by selection of a height h, platform p, width w, slope s, radius r and pitch 62.

Figure 10 shows a proximally located pull-in head 70 attached to of a protection system 71, e.g. directly to a retaining portion of the protection system 71 or to another portion of the protection system 71. The pull-in head 70 is connected to the protection system 71 by a number of shear pins 72. The shear pins 72 may preferably have a preselected strength e.g. provided by a weakening line in the shear pin, such that the shear pin may break by deliberate overloading and thereby releasing the pull-in head 70 from the protection system 71 after the protection system 71 has been installed. The pull-in head comprises a pad eye 73 for pulling e.g. using a robe or a wire.

Figures 1 la-1 Id show an embodiment of protection system/protection device with an offer anode spring arrangement 80. The offer anode spring arrangement 80 may be located on any portion of the protection system e.g. at the retaining portion or distally to the retaining portion, e.g. at an intermediate portion of a bend limiter portion, preferably at a distance from the pattern arrangement to ensure that the offer anode spring arrangement is not trapped in the cut(s) of the pattern arrangement. The offer anode spring arrangement 80 comprises a strip shaped flexible portion 83a cut in the tube shaped wall 81. The strip shaped flexible portion 83a is rooted to the tube shaped wall 81 at its root 83r. The strip shaped flexible portion 83a comprises an offer anode 88 fixed to the flexible portion 83a, preferably closed to the end of the flexible portion 83a than to the root 83r. The offer anode 88 is for example fixed to the flexible portion 83a by a shear pin 83c.

The offer anode 88 is rather large and has both an outwards protruding portion 88a with an inclined surface and an inwards protruding portion 88b with an oppositely inclined surface.

The centre line of the protection system is illustrated with the dotted line C.

In figure 11c the length of the protection system with the offer anode spring arrangement 80 is shown during installation of the protection system through an opening of a subsea structure illustrated with the subsea structure wall 84 at the periphery of the opening.

The subsea structure wall 84 presses downwards of the inclined surface of the outwards protruding portion 88a of the offer anode 88 and thereby the strip shaped flexible portion 83a is pressed downwards together with the offer anode and thereby allows the offer anode to pass through the opening.

After the protection system with the offer anode spring arrangement 80 has been installed through the opening of the subsea structure, a flexible member 89 is pulled fully through the protection system. As the flexible member 89 is pulled in, it also passes the offer anode 88 and when doing this, the flexible member 89 presses towards the oppositely inclined surface 88d of the inwards protruding portion 88b. Thereby the flexible portion 83a is pressed upwards together with the offer anode 88 and thereby allows the flexible member 89 to pass.

As illustrated in figure 11c, after the flexible member 89 has passed the offer anode spring arrangement 80, the offer anode 88, is now located on the outside of the protection system but still fixed to the flexible portion 83a. The offer anode spring arrangement 80 allows a relative large offer anode 88 to be installed at the protection system inside the subsea structure, i.e. it allows a large offer anode to pass through the opening of the subsea structure.

Figures 12a and 12b are perspective views of embodiments of retaining portions of protection devices which differs only by the number of spring arrangements.

Referring to figure 12a, the retaining portion 91 of the protection device comprises 4 retaining spring arrangements located at its tube shaped wall.

The retaining portion 91 comprises a distal end portion 94, a proximal end portion 95 and a body portion 96 between the distal end portion 94 and the proximal end portion 95. The spring arrangements are located at the body portion.

Each spring arrangement comprises a strip shaped portion 93a formed by one or more cuts 92 in the tube shaped wall of the body portion 96. A lock dog 93b (also called a locking wedge) comprising a retaining protuberance is mounted to the strip shaped portion 93a to form the retaining protuberance. Each lock dog 93b is mounted to respective strip shaped portion 93a by one or more shear pin 93c.

The outwards facing retaining protuberance of the lock dog 93b has an inclined surface forming a ramp inclining from a low level ramp end to a high level ramp end where an engagement edge 93e is formed at the high level ramp end. When the protection device with the retaining portion 91 is installed through an opening of a subsea structure, the proximal end of the protection device is pulled through the opening and as the respective lock dogs 93b are pulled through the opening the ramp inclining from a low level ramp end to a high level ensures a gradually increasing force against the flexible portion 93a that presses the flexible portion 93a and the lock dog 93b, until the engagement edge 33e has passed through the opening, where after the load is released and the flexible portion 93a, flexes back to its original position. The engagement edges 93e will now protrude beyond the periphery of the opening of the subsea structure and ensure that the part of the protection system located proximally to the retaining protuberance will not be undeliberately retracted from the opening of the subsea structure.

The shear pins 93c may comprise a weakening line for breaking at a preselected load, e.g. as described above.

The distal end portion comprises a blocking flange extends radially beyond body portion of the retaining portion, preferably in a height determined in radial direction which is at least the height of the outwards facing retaining protuberance.

The blocking flange 91a has the function of preventing the protection device from being pulled too far into the opening of the subsea structure and thereby ensures a simpler and less wear affecting installing of the flexible member through the opening of the subsea structure. In addition the locking flange 91a may serve to provide resistance during a process of deliberating overloading the shear pins connecting the pull-in head to the retaining portion for disconnecting the pull-in head.

The blocking flange 91a comprises a number of carvings 91b which may serves a markings for ensuring a desired orientation.

Distally to the clocking flange 91a, the distal end portion has a smaller inner diameter than the inner diameter of the body portion 96 of the retaining portion 91. The distal end portion may advantageously be suitable for being connected to a bend limiter portion, such as a continuous bend limiter portion at said smaller inner diameter location e.g. by a swivel connection as described above.

The proximal end portion 94 of the retaining portion 91 comprises a collar that is narrowing from the body portion and in distal direction, e.g. to a distal edge 94a or alternatively to a not shown distally located connection e.g. a swivel connection to a bend limiter portion, such as a continuous bend limiter portion.

The retaining portion of figure 12b is as the retaining portion of figure 12a except that it comprises one single spring arrangement. Figure 13 shows an installed embodiment of a protection device, where the protection device comprises a retaining portion 91 and a continuous bend limiter 97.

The retaining portion 91 may be as in the retaining portion of figure 12a and the same reference numbers for the retaining portion are used. The retaining portion 91 is connected to the continuous bend limiter 97 by swivel connections 98 connecting respectively the distal end portion 95 and the proximal end portion 94 to the continuous bend limiter 97. The subsea structure is only schematically illustrated, by a side view of a plate 99 with a not visible opening

As it can be seen the lock dog 93b ensures that the retaining portion 91 is retracted distally out of the opening.

It should be noted, that in this embodiment the offer anode spring arrangement 80 and the flexible portion 83a may or may not be plastic deformed. In an embodiment, it is desired that the flexible portion 83a is subjected to plastic deformation during installation of the protection system or of the flexible member.

Claims

PATENT CLAIMS

1. A protection system for installing a flexible member through an opening of a subsea structure, wherein the protection system comprises a retaining portion comprising a tube shaped wall and having a retaining length, wherein the tube shaped wall comprises at least one spring arrangement, wherein the spring arrangement comprises a strip shaped portion formed by one or more cuts in the tube shaped wall of the retaining portion, wherein the strip shaped portion having a flexible portion and a root where it is rooted to the tube shaped wall of the retaining portion and comprises an outwards facing retaining protuberance.

2. The protection system of claim 1, wherein the tube shaped wall of the retaining portion is substantially rigid against bends.

3. The protection system of claim 1 or claim 2, wherein the tube shaped wall of the retaining portion comprises a layer of a metal, such as steel and/or a layer of polymer, such as fibre reinforced polymer.

4. The protection system of any one of the preceding claims, wherein the cuts in the tube shaped wall comprises a pair of cuts having an average distance less than their average length, preferably the cuts are substantially equidistant cuts, optionally the pair of cuts in the tube shaped wall are cuts following parallel lines, such as straight parallel lines or curved parallel lines..

5. The protection system of any one of the preceding claims, wherein the strip shaped portion formed by the one or more cuts surrounds the strip shaped portion except for the root where it remains connected to the remaining of the retaining portion, preferably the strip shaped portion has a length extending from the root and parallel to the axis of the retaining portion which length is larger than its maximal width, such as larger than twice its maximal width.

6. The protection system of claim 4 or claim 5, wherein the cuts in the tube shaped wall comprises a cross cut providing a free end of the strip shaped portion wherein the free end of the strip shaped portion forms part of the flexible portion.

7. The protection system of any one of the preceding claims, wherein the strip shaped portion comprises a longitudinal strip shaped portion with its length oriented lengthwise relative to the retaining length.

8. The protection system of any one of the preceding claims, wherein the flexible portion of the strip shaped portion is located proximally to the root of the strip shaped portion.

9. The protection system of any one of the preceding claims 1-7, wherein the flexible portion of the strip shaped portion is located distally to the root of the strip shaped portion.

10. The protection system of any one of the preceding claims, wherein the strip shaped portion has a length and the flexible portion has a tip, wherein the outwards facing retaining protuberance is located closer to the tip than to the root, preferably immediately adjacent to the tip.

11. The protection system of any one of the preceding claims, wherein the outwards facing retaining protuberance has a maximal protruding height which is sufficient to engage and lock with an edge of the subsea structure and which maximal protruding height is sufficiently low for allowing the retaining protuberance together with at least a part of the retaining portion comprising the retaining protuberance to pass into the opening while the flexible portion of the spring arrangement is pressed into the passage of the tube shaped wall.

12. The protection system of any one of the preceding claims, wherein the outwards facing retaining protuberance has an inclined surface forming a ramp inclining from a low level ramp end to a high level ramp end, wherein the low level ramp end is proximal to the high level ramp end.

13. The protection system of claim 12, wherein the outwards facing retaining protuberance has an engagement side extending from high level ramp end and down towards the strip shaped portion, said engagement side is preferably in the form of an engagement edge.

14. The protection system of any one of the preceding claims, wherein the outwards facing retaining protuberance is provided by or comprises folds of the strip shaped portion.

15. The protection system of any one of the preceding claims, wherein the outwards facing retaining protuberance is provided by or comprises a locking wedge, the locking wedge is preferably fixed to the flexible portion of the strip shaped portion, advantageously the locking wedge comprises a flange extending beyond the free end of the strip shaped portion.

16. The protection system of claim 15, wherein the locking wedge is fixed to the flexible portion of the strip shaped portion via at least one shear pin, optionally the shear pin has a weakening line for breaking at a preselected load.

17. The protection system of any one of the preceding claims, wherein the retaining portion comprises at least two spring arrangements, such as three spring arrangements, such as four spring arrangements.

18. The protection system of any one of the preceding claims, wherein protection system consists of said retaining portion.

19. The protection system of any one of the preceding claims, wherein the protection system comprises at least one bend limiter portion, wherein the bend limiter portion comprises a length of a bend restrictor and/or a bend stiffener.

20. The protection system of claim 19, wherein the at least one bend limiter portion comprises a bend limiter located distally to the retaining portion.

21. The protection system of claim 19 or claim 20, wherein the at least one bend limiter portion comprises a bend limiter portion located proximally to the retaining portion.

22. The protection system of claim 19, wherein the protection system comprises at least one bend limiter portion located distally to the retaining portion and at least one bend limiter portion located proximally to the retaining portion.

23. The protection system of claim 19 or claim 22, wherein the at least one bend limiter portion comprises a continuous bend limiter portion passing through the retaining portion and extending both distally to the retaining portion and proximally to the retaining portion.

24. The protection system of claim 23, wherein said retaining portion being connected to said continuous bend limiter portion.

25. The protection system of claim 24, wherein said retaining portion is connected to said continuous bend limiter portion in at least one rigid connection, such as by welding.

26. The protection system of claim 24, wherein said retaining portion is swivel connected to said continuous bend limiter portion to provide that the retaining portion is swivel about the continuous bend limiter

27. The protection system of any one of the claims 23-26, wherein said retaining portion comprises a distal end portion, a proximal end portion and a body portion between said distal end portion and said proximal end portion, wherein said at least one spring arrangement is located at said body portion and wherein said body portion comprises an inner diameter, which is sufficiently large to allow the flexible portion of the at least one spring arrangement to be pressed into the passage of the tube shaped wall of the retaining portion without being blocked by said continuous bend limiter.

28. The protection system of any one of the claims 23-27, wherein said retaining portion comprises a distal end portion, a proximal end portion and a body portion between said distal end portion and said proximal end portion, wherein said at least one spring arrangement is located at said body portion and wherein said body portion comprises an inner diameter, which is at least the outer diameter of the continuous bend limiter plus the maximal protruding height of the outwards facing retaining protuberance, preferably said body portion comprises an inner radius, which is at least the outer radius of the continuous bend limiter plus the maximal protruding height of the outwards facing retaining protuberance.

29. The protection system of any one of the claims 23-28, wherein said retaining portion comprises a body portion comprising said at least one spring arrangement and wherein an annulus is formed between said body portion and said continuous bend limiter, said annulus has a height determined in radial direction which is at least the height of the outwards facing retaining protuberance.

30. The protection system of any one of the claims 27-29, wherein said retaining portion comprises a blocking flange located at said distal end portion thereof, preferably said blocking flange extends radially beyond body portion of the retaining portion.

31. The protection system of any one of the claims 27-30, wherein said retaining portion comprises a distal end portion, a proximal end portion and a body portion between said distal end portion and said proximal end portion, wherein said connection of the retaining portion to the continuous bend limiter portion comprises at least one connection located at the proximal portion of the retaining portion to the continuous bend limiter and/or at least one connection located at the proximal portion of the retaining portion to the continuous bend limiter.

32. The protection system of any one of claims 19-31, wherein the at least one bend limiter portion comprises a tube shaped wall having a bend limiter length and comprising a cut pattern comprising one or more through cuts through the bend limiter tube shaped wall.

33. The protection system of claim 32, wherein the bend limiter tube shaped wall comprises a layer of a metal, such as steel and/or a layer of polymer, such as of fibre reinforced polymer.

34. The protection system of claim 32 or claim 33, wherein the cut pattern comprising at least one cut slot.

35. The protection system of any one of claims 32-34, wherein the cut pattern is sufficient for allowing the bend limiter portion to bend with a selected bending radius, wherein the selected bending radius is from 0.5 to 25 m, such as from 2 to 10 m.

36. The protection system of any one of claims 32-35, wherein the cut pattern comprises cut(s) extending in substantially the entire circumference of the tube shaped wall.

37. The protection system of any one of claims 32-36, wherein the cut pattern comprising a meandering pattern, preferably extending partly or fully in the circumference of the metal wall.

38. The protection system of any one of claims 32-37, wherein the cut pattern comprises a helically meandering pattern.

39. The protection system of any one of claims 32-38, wherein the helically meandering pattern, preferably having a trapezoid meandering pattern.

40. The protection system of any one of claims 32-39, wherein the at least one bend limiter portion is connected to the retaining portion optionally via an intermediate portion.

41. The protection system of any one of claims 32-40, wherein the at least one bend limiter portion is integrated with the retaining portion, preferably the at least one bend limiter portion and the retaining portion comprises respective sections of a common tubular.

42. The protection system of any one of claims 32-41, wherein the protection system comprises at least two bend limiter portion, including at least one bend limiter portion integrated with the retaining portion and at least one bend limiter portion connected to the retaining portion e.g. via another bend limiter portion.

43. The protection system of any one of claims 32-42, wherein the at least one of the bend limiter portion(s) comprises an external polymer tube extending in at least a part of the length of the bend limiter portion.

44. The protection system of any one of claims 32-43, wherein at least one of the bend limiter portion(s) comprises an internal polymer tube extending in at least a part of the length of the bend limiter portion.

45. The protection system of any one of the preceding claims, wherein at least one of the retaining portion and the one or more bend limiter portions comprises an internal wear coating, such as a wear coating of a polymer or a polymer containing composition, such as a coating comprising one or more of polyurethane (PU), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF), e.g. in a thickness of from 5 pm to 5 mm, , such as from 10 pm to 1 mm, such as from 25 pm to 0.1 mm

46. The protection system of any one of the preceding claims, wherein at least one of the retaining portion and the one or more bend limiter portions and/or one or more intermediate portions is lined with an internal polymer tube arranged inside the portion or portions, the internal polymer tube may advantageously have a thickness of 0.5 mm to 5 cm, such as from 1 to 10 mm.

47. The protection system of any one of the preceding claims, wherein the protection system comprises at least one offer anode, said offer anode preferably being attached to the retaining portion, the at least one bend limiter portion and/or an intermediate portion and wherein at least a part of the offer anode preferably protrudes outwards from said portion(s) to which it is attached.

48. The protection system of claim 37, wherein the offer anode being attached to a strip shaped flexible portion of an offer anode spring arrangement located on a tubular portion of the protection system, wherein the tubular portion defines a passage and the strip shaped flexible portion of the offer anode spring arrangement is configured for being pressed inwards to the passage of the tubular portion to allow the offer anode to pass into the opening of the subsea structure where after having passes the opening, the strip shaped flexible portion of the offer anode spring arrangement returns to its non-pressed stage.

49. The protection system of claim 47 or claim 48, wherein the offer anode being attached to a tubular portion of the protection system, wherein a piece of material is cut from the tubular portion and the offer anode being located to at least partly fill out the space made by cutting out the material piece

50. The protection system of any one of the preceding claims, wherein the protection system comprises a blocking flange located distally to the spring arrangement(s) of the retaining portion and extending radially beyond the periphery of the tube shaped wall of the retaining portion.

51. The protection system of claim 40, wherein the blocking flange comprises a blocking collar, the blocking collar is advantageously located distally on the retaining portion or on an intermediate portion located between the retaining portion and a bend limiter portion.

52. The protection system of any one of the preceding claims, wherein the protection system comprises a proximally located pull-in head attached to or attachable to the retaining portion, optionally via one or more other tube shaped portion(s) of the protection system located proximally to the retaining portion.

53. The protection system of claim 52, wherein the pull-in head is attached to or attachable to the retaining portion via a bend limiter portion.

54. The protection system of claim 52 or claim 53, wherein the pull-in head is attached to or attachable to the retaining portion through shear pin(s) that enable disconnecting the pull-in head from the retaining by deliberate overloading.

55. The protection system of any one of the preceding claims, wherein the protection system comprises a plurality of tubular portions including said retaining portion and said optional one or more bend limiter portions and/or said optional one or more intermediate portions.

56. The protection system of any one of the preceding claims, wherein at least one of the retaining portion and the one or more bend limiter portions and/or one or more intermediate portions is/are covered with an external polymer tube arranged outside the portion or portions, the external polymer tube may advantageously have a thickness of 0.5 mm to 10 cm, such as from 1 to 3 cm, such as from 2 to 10 mm.

57. A protection device for installing a flexible member through an opening of a subsea structure, the protection device comprises a retaining portion, wherein the retaining portion comprises at least one spring arrangement and the at least one bend limiter portion comprises cut pattern comprising one or more through cuts through a wall of the steel tubular, preferably the protection device comprises a tubular having a length and comprising a plurality of tubular portions including said retaining portion and at least one bend limiter portion.

58. The protection device of claim 57, wherein the protection device forms part of the protection system of any one of claims 1-56.

59. The protection device of claim 57 or claim 58, wherein the spring arrangement comprises a strip shaped portion formed by cuts in the tube shaped wall forming a passage, wherein the strip shaped portion having a flexible portion and a root where it is rooted to the tube shaped wall of the retaining portion and comprises an outwards facing retaining protuberance adapted for engaging with the subsea structure.

60. The protection device of any one of claims 57-59, wherein the plurality of tubular portions comprising at least the retaining portion and the at least one bend limiter portion are of same material or materials, such as a layered structure of materials, and preferably comprises one layer of a metal and/or a polymer, such as a fibre reinforced polymer extending in the entire length of the tubular, preferably the tubular comprises a layer of steel in its entire length.

61. The protection device of any one of claims 57-60, wherein the at least one bend limiter portion comprises a continuous bend limiter portion passing through the retaining portion and extending both distally to the retaining portion and proximally to the retaining portion.

62. The protection device of claim 61, wherein said retaining portion being connected to said continuous bend limiter portion.

63. The protection device of claim 62, wherein said retaining portion is connected to said continuous bend limiter portion in at least one rigid connection, such as by welding.

64. The protection device of claim 62, wherein said retaining portion is swivel connected to said continuous bend limiter portion to provide that the retaining portion is swivel about the continuous bend limiter

65. The protection device of any one of the claims 61-64, wherein said retaining portion comprises a distal end portion, a proximal end portion and a body portion between said distal end portion and said proximal end portion, wherein said at least one spring arrangement is located at said body portion and wherein said body portion comprises an inner diameter, which is sufficiently large to allow the flexible portion of the at least one spring arrangement to be pressed into the passage of the tube shaped wall of the retaining portion without being blocked by said continuous bend limiter.

66. The protection device of any one of the claims 61-65, wherein said retaining portion comprises a distal end portion, a proximal end portion and a body portion between said distal end portion and said proximal end portion, wherein said at least one spring arrangement is located at said body portion and wherein said body portion comprises an inner diameter, which is at least the outer diameter of the continuous bend limiter plus the maximal protruding height of the outwards facing retaining protuberance, preferably said body portion comprises an inner radius, which is at least the outer radius of the continuous bend limiter plus the maximal protruding height of the outwards facing retaining protuberance.

67. The protection device of any one of the claims 61-66, wherein said retaining portion comprises a body portion comprising said at least one spring arrangement and wherein an annulus is formed between said body portion and said continuous bend limiter, said annulus has a height determined in radial direction which is at least the height of the outwards facing retaining protuberance.

68. The protection device of any one of the claims 65-67, wherein said retaining portion comprises a blocking flange located at said distal end portion thereof, preferably said blocking flange extends radially beyond body portion of the retaining portion.

69. The protection device of any one of the claims 61-68, wherein said retaining comprises a distal end portion, a proximal end portion and a body portion between said distal end portion and said proximal end portion, wherein said connection of the retaining portion to the continuous bend limiter portion comprises at least one connection located at the proximal portion of the retaining portion to the continuous bend limiter and/or at least one connection located at the proximal portion of the retaining portion to the continuous bend limiter.

70. A method of installing a flexible member in a subsea structure using a protection system of any one of claims 1-56 and/or a protection device of any one of claim 57-69 , wherein the method comprising pulling the flexible member through an opening in the subsea structure, wherein the method comprises

- inserting the flexible member through a tubular comprising at least said retaining portion of the protection system and/or protection device of any one of the preceding claims and mounting an end portion of the flexible member to a pull-in head;

- attaching the pull-in head to the retaining portion optionally via another tubular portion of the tubular proximally located to the retaining portion, such as the bend limiter portion; - pulling the pull-in head and at least a part of the retaining portion comprising the one or more flexible portions carrying a retaining protuberance through the opening, until the retaining portion engages with the opening in the subsea structure; - releasing the pull-in head from the tubular and pulling the flexible member further into the structure to its final position.

71. A method of claim 70, wherein the pulling in of least a part of the retaining comprising the one or more flexible portions carrying a retaining protuberance through the opening results in pressing the flexible portion downwards to allow the retaining protuberance passing into the opening where after when the retaining protuberance has passed fully through the opening or a narrower portion thereof, the downwards pressure of the flexible portion is released and the retaining protuberance engages with the opening in the subsea structure to form an obstacle preventing the retaining portion from retract backwards through the opening.