EP0921061A1 - Docking apparatus for a floating structure - Google Patents

Abstract

The lower part of the mooring device extends to the sea bed (5) and the upper part is connected to a linkage (17,18) which can move radially relative to the well and turret. Each linkage has a key (17) fitting into a radial notch (16) in the edge of a horizontal table (14) forming the bottom of the turret, so the key can move radially relative to the turret and the shaft The lower part of the vessel shaft has a stage fixed coaxially against its internal surface, with upper surface covered with an anti-friction coating. Each key is mounted without play between two lateral radial surfaces of the notch and with a certain radial play relative to a rear surface, so the key can move in the radial direction between the rear surface and the internal wall of the shaft. The lateral radial surfaces are covered with an anti-friction coating. The key is pivoted about the turret by a strap with horizontally articulated links to the turret and the key. Each strap connected to a key is made of a number of rigid connecting rods parallel to each other and articulated at the ends about a horizontal axis. Each connecting rod has two parallel arms. A guiding tube for a mooring chain is connected to the key and to the lower end of each connecting rod. Each guiding tube has an end support with an opening through it for the chain and means of holding the chain which moves between allowing free movement through the support and holding it. The device has three mooring lines and three keys each fitted into a notch in the table, arranged at 120 degree intervals around the axis of the turret. Each mooring line has four parallel chains connected to one key.

Description

The invention relates to a mooring device for a structure floating and in particular for a boat used for drilling at sea or for the exploitation of oil or gas wells underwater.

We know boats used for drilling at sea or for exploitation oil or gas wells having a wellhead at the bottom of a sea or ocean. It is necessary to ensure a mooring of these boats, so as to avoid drifting of the boat during drilling or the operation of a well, for example under the effect of currents or wind.

There are known boat mooring systems used for operation offshore oil whose hull is crossed by a shaft well vertical opening into the open air at its top, at a bridge upper part of the boat and, at its lower part, in the body of water on which floats the boat, at the bottom of the hull, below the waterline. The vertical well can be used in particular to make pass the drill string or the well operating conduits to across the hull of the boat, towards the bottom of the body of water on which floats the boat.

There are known boat mooring devices comprising a vertical shaft wells passing through the hull, which include a turret arranged in the well in a substantially coaxial arrangement relative to the well which is rotatably mounted, via its upper part, on the hull of the boat, around the vertical axis of the well.

Mooring means such as constituted mooring lines by chains are connected to the turret and are distributed around the axis of the turret, so as to oppose the drift of the turret, under the effect of transverse forces exerted on the boat. Because the turret is held in place, the boat, which is connected via a bearing to the upper part of the turret is held against forces transverse, so that any drift of the boat is avoided. The boat does can only rotate around the axis of the turret, because it is rotatably mounted relative to the turret via the upper bearing.

When mooring lines with a lower part extending towards the bottom of the sea or the ocean are connected by their upper part, directly to the lower part of the turret which is generally made in the form of a circular horizontal table placed with a certain radial clearance in the lower part of the vertical shaft, the assembly transverse forces and torques exerted by the boat on the turret maintained by the mooring lines is transmitted by the upper bearing which must therefore be designed in a massive and very resistant manner.

It is possible to have some of these efforts taken over by the table constituting the lower part of the turret, placing it against the surface inside of the vertical shaft, in its lower part opposite the table, a coaxial bearing at the well and at the table through which the table can come to bear against the vertical well of the hull of the boat, under the effect transversal efforts. However, in this case, the bearing and the lower part of the vertical well are subjected to shocks or forces which may be the cause of a deflection of the body of the turret and a deformation of the bearing, for example by ovalization.

It may therefore be preferable to link the upper parts mooring lines with the turret, via link pivotally mounted on the turret around a horizontal axis, so to be able to move each in a radial direction of the vertical well and the turret, under the effect of the forces exerted by the mooring lines to come to bear on a lower bearing of the tank well. However, in this case, the torque exerted by the mobile boat rotating around from the axis of the vertical well is transmitted to the mooring lines, via connecting members articulated on the turret, so that these members of articulated links which undergo the torque risk of deforming and to be damaged.

The object of the invention is therefore to propose a mooring device for a floating structure having a hull crossed by a shaft well vertical, comprising a turret arranged in the well and rotatably mounted by its upper part on the hull of the floating structure, around the vertical axis of the well, mooring means distributed around the axis of the turret, each having a lower part extending towards the bottom of a body of water on which the floating structure and part of it are supported upper connected to a link member mounted movable in one direction radial with respect to the well and the turret, this device making it possible to resume the transverse forces and the torque exerted by the floating structure, without risk of damage to the means of connection mooring.

For this purpose, each of the connecting members includes a key housed in a radial direction notch in a peripheral part a horizontal table constituting a lower part of the turret, so that the key to which is connected at least one mooring means either movable in a radial direction relative to the turret table and relative to the inner wall of the vessel well.

Preferably, the key is pivotally suspended from the turret, by means of at least one tie rod having connecting axes articulated with the turret and the key, horizontal direction

In order to clearly understand the invention, we will describe, by way of examples, referring to the attached figures, several modes production of a mooring device according to the invention of a boat used for offshore oil exploitation.

Figure 1 is a schematic elevational view in partial section of a boat comprising a mooring device according to the invention.

Figure 2 is an elevational view in section through a vertical plane of the part of a mooring device according to the invention and according to a first embodiment arranged in the vertical well of the boat.

Figure 3 is a sectional view along 3-3 of Figure 2.

Figure 4 is a sectional view similar to the view of Figure 2 of an alternative embodiment of the mooring device.

Figure 5 is an elevational view in partial section along 5-5 of Figure 6 of the upper part of an articulated connecting member of the device mooring.

Figure 6 is a top view of the upper part of the device articulated link shown in Figure 5.

Figure 7 is a top view and in section through a horizontal plane of the lower part of an articulated connecting member of the mooring device.

Figure 8 is a sectional and elevational view along 8-8 of the figure 7.

In Figure 1, there is shown a boat with a device mooring according to the invention, generally designated by the reference 1.

The boat 1 has a hull 2 crossed by a vertical well 3 the upper part of which opens into the open air, at the level of an upper deck 4 of hull 2 of boat 1.

The vertical well 3 opens, at its lower part, through the bottom of the hull 2 of the boat 1, in the sea water 5 on which the boat floats 1.

Sea water 5 fills the vertical well 3, up to a corresponding level 6 at the waterline of the boat.

In the case of a boat 1 used for petroleum exploitation, the height in the axial direction of the central part of the shell 2 and therefore the length of the well in the axial direction are of the order of 30 meters. The well has a diameter of the order of 7 to 8 meters.

The boat mooring device 1 comprises a turret 7 of generally cylindrical shape arranged coaxially inside the well 3 and mooring lines 8 connected to connecting parts at level from the lower end of the turret 7, as will be explained thereafter with reference to FIGS. 2 and 3.

Each of the mooring lines 8 which is constituted by a set very long chains (several kilometers or more tens of kilometers) is made up of very large links and significant mass.

Each of the mooring lines 8 has a lower part 8a extending towards the bottom 9 of the sea 5 which is made up of chains which are generally attached to anchors on the sea floor 9, at their end part resting on the bottom of the sea.

Each of the lines 8 has an upper end portion 8b which is connected to a connecting member at a lower end portion of the turret 7, as will be described below.

The anchor lines 8 are distributed around the axis 10 of the vertical well 3, so as to maintain the turret 7 in a position substantially fixed relative to the bottom 9 of the sea 5.

In the embodiment shown in Figures 2 and 3, the device mooring has three anchor lines each consisting of four chains, the upper end parts of which are connected to connecting members at the level of the lower part of the turret 7, in three zones distributed around the axis 10 of the turret and the vertical shaft 3, whose positions are located 120 ° from each other around the axis 10.

The turret 7 comprises an upper table 11 constituted by a very thick rigid circular structure, perpendicular to the vertical axis 10 of the turret, by means of which the turret 7 is rotatably mounted on the upper part of the hull 2 of the boat, around the axis 10 vertical well 3, using a roller crown 12. The roller crown 12 is fixed by means of a support 12a on the upper part of the hull 2 of the boat, the support 12a comprising an annular support plate which is fixed by screwing on the upper part of the shell 2, around from the upper end of well 3.

The roller ring 12 includes a set of rollers 13a with horizontal axes mounted on the internal lower part of the crown 12, on which the upper table 11 of the turret rests 7. The rolling ring 12 also includes a set of rollers bearing 13b with horizontal axes fixed on the internal upper part of the crown 12, coming to bear on the upper surface of the table 11. Finally, the crown 12 includes a set of rollers 13c with axes vertical fixed on the internal cylindrical surface of the crown 12 coming in contact with the outer cylindrical edge of the upper table 11. De in this way, the upper table 11 is perfectly maintained and guided rotating around the axis 10 of the vertical well 3.

In the case where the rolling diameter of the roller crown 12 can be limited to a value of around 7 meters, the roller crown can be made in one piece. On the other hand, in the case where the diameter bearing of the crown 12 is greater than 7 meters, it can be necessary to make the roller crown 12 in several sectors which are assembled and fixed on the support 12a.

The lower end part of the turret 7 is constituted by a circular table 14 at which the upper ends of the lines anchor 8 are connected to connecting members in the manner which will be explained later.

The diameter of the table 14 is significantly less than the diameter inside the well 3, so that there remains a free space of a certain width between the peripheral edge of the table 14 and the internal surface of the lower part of the well 3.

A support bearing 15 is fixed, in a coaxial arrangement, against the internal surface of well 3, in its lower part, opposite the table 14. However, there remains a radial clearance of the order of 30 mm between the surface external device of the table 14 and the internal bearing surface of the bearing 15.

The turret 7 is produced in a circular hollow form, such so that we can pass inside, in the vertical direction, tubes or pipes from the upper part of the hull 2 of the boat, towards the bottom of the sea.

The table 14 constituting the lower part of the turret 7 comprises, in its peripheral part, three notches 16 of radial direction opening out on the outer peripheral surface of the table 14 and extending along the entire thickness of the table 14.

The notches 16 are arranged in three zones of the table 14 including the positions are located at 120 ° from each other around the axis 10 of turret 7.

In each of the notches 16 in the peripheral part of the table 14 is arranged a key 17 to which the ends of the chains constituting an anchor line 8.

The key 17 has a width in the circumferential direction slightly less than the width of the notch 16, so that the key 17 is freely mounted inside the notch 16, which allows it to be move in the radial direction of the turret 7, towards the surface internal of the bearing 15 fixed to the lower part of the well 3, facing the table 14. In addition, the key 17 has a length in the direction radial less than the radial length of the notch 16, so that the key has a certain radial clearance inside the notch 16, between the rear surface 16a of the notch 16 and the internal surface 15a of the level 15.

Each of the keys 17 is suspended from the upper table 11 of the turret 7, by means of a suspension tie rod 18.

The suspension tie rod 18 is mounted articulated at one of its ends on the upper table 11 and at its other end on the key 17, around respective horizontal axes 18a and 18b.

As can be seen in FIGS. 5 and 6, the upper table 11 of the turret 7 is crossed by an opening 19 of reinforced rectangular shape at the periphery by a frame 20 of rectangular current section.

Inside the frame 20, are arranged, in transverse directions, T-shaped suspension plates 21 which are welded on the frame 20. The suspension plates 21 delimit successive spaces inside the frame 20 in each of which can be mounted pivoting a link 38 made up of two parallel arms 38a and 38b suspended from a shaft 22 mounted and stopped in rotation between two plates 21. The spacing between the arms 18a and 18b is maintained by a spacer tube 23 engaged on the shaft 22.

Each of the tie rods 18 mounted pivoting about a horizontal axis at the interior of the frame 20 ensures the suspension of a key 17 in which are received and fixed the ends of the chains of an anchor line 8.

In the case where each of the anchor lines has four chains, the key 17 is suspended from the upper table 11 of the turret 7, by means of four links 18 each comprising two arms 38a and 38b parallel to each other and arranged with a certain spacing.

As can be seen in Figures 7 and 8, the key 7 is made in the form of a box of substantially parallelepiped shape having an external wall 17a directed towards a bearing and sliding surface 15a of bearing 15, the shape of which in portion of a cylinder corresponds to the shape of the bearing surface of the bearing 15 disposed opposite.

The key 17 also has walls 17b parallel to each other and substantially perpendicular to the support wall 17a of the key.

The walls 17b delimit between them successive spaces in each of which penetrates the lower end part of a link 38.

The walls 17b are interconnected and held by ribs 24.

Each of the walls 17b has, at its rear end opposite to the support wall 17a, a recess for the engagement of two ends shaft 25 integral with the body 26 of a tubular chain guide device 27.

On the shaft ends 25 are engaged the lower end parts arms 38a and 38b of a link 38 which are crossed by shaft end openings 25. The body 26 of the device chain guide against which the end parts of the arms 38a and 38b come into support constitutes both a spacer maintaining the spacing arms 38a and 38b and a circular support.

The shaft ends 25 are held in half bores (cut diametral) on the walls 17b, by caps 28 having the other half-bore and fixed by screws to the walls 17b.

In this way, each of the rods 18 arranged in a space between two successive walls 17b is hingedly connected to the key 17 and the chain passage device 27 of tubular shape which is fixed in an opening passing through the body 26.

The rods 38 which are fixed by their lower part, so articulated, with key 17, about a common horizontal articulation axis 29 constitute a tie rod 18.

As can be seen, in particular in FIG. 8, the devices for guide chains 27 or "fairleads" are produced in tubular form and successively comprise a frustoconical engagement part of a chain and a coaxial cylindrical part engaged in the opening of the body 26 in a direction 30 inclined to the horizontal plane. The angle of inclination of the axes of the fairleads 27 is at least equal to 20 °.

Each of the fairleads 27 has an enlarged end flange diametrically 31 in its end part located at the rear of the link 38.

On the flange 31 is fixed a slide 32 on which is mounted sliding, in a direction perpendicular to the axis of fairlead 27, a wedge 33 having a central opening in which the part is housed lower of the first link of the anchor chain 34, in the position of blocking of the shim 33, as shown in FIG. 8.

Shim 33 can be moved between a low position out of service in which the shim 33 is supported on the lower part of the slide 32 constituting a support heel and a high service position shown in Figure 8 in which the wedge 33 ensures the blocking of the chain 34 of the mooring line.

When the shim 33 is in its out-of-service position, the opening of exit from fairlead 27, at the flange 31, is free, so that can move the chain inside the fairlead, by pulling in the direction 30 to ensure the tension of the anchor line, for example by using a winch carried by the hull 2 of the boat.

When we hoisted the chain in the fairlead, we move the wedge 33 in its high service position in which the shim 33 ensures the blocking of a part of a link of the chain 34 introduced into the wedge 33, by through a bearing surface.

Each of the chains 34 introduced into a guide fairlead 27 connected to the key 17 is tensioned and then blocked by a similar stop piece at stop 33.

The upper end of the anchor line, the fairlead and the landing 15 are immersed in the body of water on which the boat 2 floats. done, the part 33 is not accessible and its movements between its position out of service and its service position is achieved using a motor remotely controlled, for example from the upper deck of the boat.

When the fixing has been carried out, as indicated above, of the assembly chains 34 of the anchor line 8 connected to the key 17, the key 17 is recalled in the radial direction towards the internal surface 15a of the bearing 15 coaxial with the well 3 of the shell 2.

As shown in Figure 7, the vertical side surfaces in the radial direction of the notch 16 of the table 14 are each covered an anti-friction lining 14a or 14b. Key 17 is mounted sliding between the linings 14a and 14b, practically without play, so that the key 17 recalled in the radial direction by the mooring line 8 can only move in the radial direction, and only the outer surface of the front wall 17a of the key 17 comes to bear against the internal surface 15a of the bearing 15 covered with an anti-friction lining 15c constituting a sliding surface of the keys during movement relative in rotation of the boat and the turret.

The inclination of the anchor lines 8, which corresponds to the angle of inclination of the axis 30 of the fairleads 27, is chosen so that part predominant of the horizontal component of the force exerted by the lines mooring is exerted directly on the internal surface of the bearing 15 integral from the hull well.

The angle of the axis 30 of the fairleads with the horizontal plane can be between 20 ° and 80 °.

A certain fraction of the vertical force exerted by the weight of the line also acts directly on the internal surface of the bearing 15.

This significantly reduces the forces transmitted to the table upper 11 of the turret 7, by means of the tie rod 18.

The fact that each rod of the tie rod 18 is articulated to one of its ends on the upper table 11 of the turret 7, around an axis 18a horizontal, allows movement by pivoting in the radial direction of the key 17 towards the internal surface 15a of the bearing 15. When the boat is stressed by transverse forces, the support keys against the surface 15a of the bearing 15 prevents impacts from occurring between table 14 of turret 7 and bearing 15 of well 3 and between rear surface of the keys and the rear surface of the notches 16. Because of its articulation around the axis 29 parallel to the articulation axis 18a of the rods 38 on the turret 7, the key 17 can be oriented so as to come in perfect support against the internal surface 15a of the bearing 15. It improves thus the transmission of forces between the mooring lines and the hull of the boat. In addition, the key 17 is mounted practically without play inside of the notch 16 of the table 14, so that all of the couples acting on the turret 7, due to the couples exerted by the shell 2 are taken up at table 14, and transmitted directly to the mooring lines 8. This avoids transmitting torques to the upper bearing 12 of turret 7.

The torques are taken up by mooring lines 8, directly at level of the lower table 14, via the keys 17, the lines mooring 8 and the notches 16 of the table 14 in which the keys are placed being distributed around the axis 10 common to the vertical well 3 and turret 7.

The keys 17 are made of a corrosion-resistant material by seawater, such as a nickel alloy or ferritic iron silicon.

The keys 17 are mounted completely free inside the notches 16 of table 14 and have only one latitude of movement in the radial direction.

In Figure 4, there is shown an alternative embodiment of the device mooring. The corresponding elements in Figures 2 and 4 bear the same references with, however, the exhibitor '(prime) with regard to the elements of the variant embodiment shown in FIG. 4.

The mooring device is similar, in its general structure, to mooring device described with reference to FIG. 2 and comprises a turret 7 'rotatably mounted via a crown 12' inside the well 3 'passing through the hull 2' of a boat.

The lower table 14 'of the turret 7' has notches 16 ' in each of which is inserted a key 17 '. The 16 'notches and the keys 17 'are distributed around the axis 10' common to the turret 7 ' and to the well 3 'and each of the keys 17' is integral with the upper part an 8 'mooring line.

We can use for example three mooring lines 8 'connected to three 17 'keys mounted in 16' notches of the table 14 'at 120 ° around from the axis 10 'of the turret 7'.

The notches 16 'in the same way as the notches 16 of the device shown in Figure 2 have a length in the radial direction greater than the radial length of the keys 17 ', so that the keys 17 'are mounted with a certain clearance between the rear surface 16'a of the notch 16 'and the internal surface 15'a of the bearing 15' integral with the internal surface of the well 3 'in its lower end part.

The keys 17 'are mounted articulated at the end of tie rods 18' which can be constituted, as before, by a set of rods parallel to each other and each consisting of two parallel arms.

Unlike the embodiment shown in FIG. 2, the 18 'tie rods suspension 17' are not fixed to the upper table 11 'from the turret 7', at their upper part, but on ears 35 integral with the body of the turret 7 'and arranged at 120 ° from one another around from the axis 10 'of the turret. In this way, the upper axis 18'a of articulation of the tie 18 'on the turret 7' is at a level substantially lower than the level of the upper table 11 '. This avoids the use of very long rods (for example of the order of 30 m), the ears 35 and the axes 18'a being placed a few meters above the lower table 14 '. On the other hand, the pivot angle of the tie rods 18 'for obtaining the support of the keys 17 'on the bearing 15' is greater than the angle of pivoting in the case where the upper link of the tie rod is placed at the upper level of the turret.

The operation and advantages of the mooring device according to the variant are substantially identical to the operating mode and the advantages of the device described above.

In particular, the mooring lines 8 'distributed around the axis 10' recall the keys 17 'in the radial direction, against the surface interior 15'a of bearing 15 '.

During transverse movements of the boat, this avoids all impact of the rear part of the keys 17 'on the internal surface 16'a of the notch 16 '.

In addition, the couples exerted on the turret 7 'are taken up directly by the mooring lines 8 ', at the level of the lower table 14', from fact that the keys are mounted practically without play in the notches 16 '.

The articulation of the keys 17 'around a horizontal axis 29' at the end lower of the tie rod 18 'allows an orientation of the key which comes in contact through its entire front surface with the internal surface 15'a of the bearing 15 '.

The invention therefore generally makes it possible to avoid transmitting excessive forces or torques at the upper bearing of the turret 7 'and any risk of shock between the attachments of the mooring lines and the lower part of the turret.

The invention is not limited to the embodiments which have been described.

This is how you can use any number of lines mooring themselves made up of any number of chains or cables placed in parallel and connected to a key mounted mobile in the radial direction relative to the turret.

In all cases, however, the mooring lines are distributed regularly around the axis common to the hull well and the turret, so as to take up the torques and transverse forces exerted on the boat and through it on the turret kept immobile by the mooring lines.

The tie rods can consist of one or more rods rigid arranged in parallel or by one or more rods or cables arranged substantially vertically and connected at one of their ends to a part of the turret and at their other end to a key.

The tie rods can be connected to the turret, in any area of the turret, depending on its height, depending on the characteristics sought for the mooring device.

The tie rods consisting of rods or cables could be connected, by their upper part, to the hull of the boat, instead of being connected with the turret, to ensure the suspension of the keys.

The keys could also be mounted sliding in a radial direction on a horizontal part of the lower table of the turret ; in this case, the keys would be both housed between two surfaces lateral radial direction of the table and resting on the table. In in all cases, the keys can only move in the radial direction and are integral in rotation with the turret.

Mooring lines can be connected in any way on the keys, the use of fairleads, as described, allowing ensure effective guidance of the upper part of the components mooring lines.

The invention applies not only to boats used in the underwater oil exploitation but also in the case any floating structure used for offshore petroleum exploitation or in any other form of sea activity in which it is necessary to immobilize a floating structure, on the surface of the sea or ocean.

Claims (12)

Mooring device for a floating structure (1) having a shell (2, 2 ') crossed by a well (3, 3') with a vertical axis, comprising a turret (7, 7 ') arranged in the well (3, 3') and rotatably mounted by its part upper (12, 12 ') on the hull (2, 2') of the floating structure (1) around the vertical axis (10, 10 ') of the well (3, 3'), mooring means (8, 8 ') distributed around the axis (10, 10 ') of the turret (7, 7') each having a lower part extending towards the bottom of a body of water (5) on which floats the floating structure (1) and an upper part connected to a connecting member (17, 18, 17 ', 18') mounted movable in a radial direction relative to the well (3, 3 ') and turret (7, 7'), characterized in that each of the organs connection (17, 18, 17 ', 18') includes a key (17, 17 ') housed in a notch (16, 16 ') of radial direction in a peripheral part a horizontal table (14, 14 ') constituting a lower part of the turret (7, 7 '), so that the key (17, 17') to which is connected to the at least one mooring means (8, 8 ') is movable in a radial direction relative to the horizontal table (14, 14 ') and relative to the internal wall (15a, 15'a) of the lower part (15) of the tank well (3, 3 '). Device according to claim 1, characterized in that the lower part of the tank well (3, 3 ') has a bearing (15, 15') fixed against the internal surface of the lower part of the tank well (3, 3 '), in a coaxial arrangement. Device according to claim 2, characterized in that a surface (15a, 15'a) of the bearing (15, 15 ') directed towards the inside of the well tank (3, 3 ') is covered with an anti-friction lining. Device according to any one of claims 1 to 3, characterized by the fact that each of the keys (17) is mounted practically without play between two lateral surfaces of radial direction of the notch (16) and with some play in the radial direction with respect to a surface rear (16a, 16'a) of the notch (16, 16 '), so that the key (17, 17 ') has a certain clearance in the radial direction between a rear surface (16a, 16'a) of the notch (16, 16 ') and the internal wall (15a, 15'a) from the well (3). Device according to claim 4, characterized in that the lateral surfaces of radial direction of the notch (16) are covered an anti-friction lining (14a, 14b). Device according to any one of claims 1 to 5, characterized by the fact that the key (17, 17 ') is pivotally suspended to the turret (7, 7 '), via at least one tie rod (18, 18') having hinge pins articulated to the turret (7, 7 ') and to the key (17, 17 '), horizontal direction, Device according to claim 6, characterized in that each of the tie rods (18, 18 ') connected to a key (17, 17') consists of a plurality of rigid rods (38) parallel to each other hinged to one of their ends or lower end on the key (17), around an axis common horizontal (29) and at their upper part, on the turret (7) around a horizontal axis (18a) parallel to the articulation axis (29) of the rods on the key (17). Device according to claim 7, characterized in that each of the links (38) consists of two parallel arms (38a, 38b) between them. Device according to either of Claims 7 and 8, characterized in by the fact that a guide tube (27) of a mooring chain (34) is connected to the key (17) and to the lower end of each of the rods (38) of the tie rod (18). Device according to claim 9, characterized in that each of the guide tubes (27) of a mooring chain (34), or fairleads, has an end flange (31) through which an opening for passage of the mooring chain (34), at the exit of the fairlead (27) and a wedge (33) for blocking the chain (34) movable between an out-of-service position allowing free passage of the mooring chain (34) through the fairlead (27) and a position for blocking the mooring chain (34) by compared to the fairlead (27). Device according to any one of Claims 1 to 10, characterized by the fact that it has three mooring lines (8) and three keys (17) each inserted in a notch (16) of the horizontal table (14) of the turret (7), distributed at 120 ° around the axis (10) of the turret (7) and the vertical well (3). Device according to claim 11, characterized in that each of the mooring lines (8) has four chains (34) arranged parallel to each other and connected to a key (17).

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