GB1585856A

GB1585856A - Floating body which includes a device for tautening anchoring lines attached to the body

Info

Publication number: GB1585856A
Application number: GB12473/78A
Authority: GB
Original assignee: Societe National Elf Aquitaine
Current assignee: Societe National Elf Aquitaine
Priority date: 1977-04-01
Filing date: 1978-03-30
Publication date: 1981-03-11
Also published as: FR2385584B1; ES468424A1; IT1093963B; BR7801994A; FR2385584A1; JPS54389A; DE2813937A1; NL7803476A; NO147667B; AU3463078A; CA1094400A; SE7803681L; GR65953B; EG14425A; NO147667C; IT7821745A0; NO781148L; AU515981B2; AR214001A1

Description

(54) A FLOATING BODY WHICH INCLUDES A DEVICE FOR TAUTENING ANCHORING LINES ATTACHED TO THE BODY (71) We, SOCIETE NATIONALE ELF AQUiTAINE (PRoDUCTIoN), a French Com- pany, of Tour Aquitaine, 92400 Courbevoie, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention concerns a floating body which includes a device for tautening anchoring lines attached to the body.

Floating bodies such as buoys used for oil or gas storage or to carry separation installations or flares, have to remain at a given location during the whole or part of the life of the associated production field.

Mooring lines are therefore fixed round the outer edges of such objects, sometimes in quite large numbers. In certain cases, for bodies with a very large displacement, or when conditions at sea are particularly rough, double lines are fitted.

In existing installations, each line runs over a pulley, passes through a brake and is connected to a special winching system.

The deck surface of such moored bodies therefore has to accommodate a winching system for every line, which increases weight, takes up space, and involves considerable outlay for equipment that is used only at certain times, generally at the beginning and end of a production run.

American Patent 3 191 201 (Richardson) describes a device for tautening mooring lines on a floating body. This comprises one winch for each cable, attached to a ringshaped plate, coaxial with a well, through which the lines pass downwards through the floating body; this plate is angularly movable round the well axis.

Such a device allows the floating body to be orientated in relation to the anchoring lines, which is useful for elongated floating objects such as ships. When this solution for a particular nautical problem is applied to floating objects in general, however, it is subject to the same criticisms as those already mentioned, concerning weight and cost.

According to the invention there is provided a floating body provided with a plurality of stoppers arranged to co-operate with anchoring lines which in use are arranged on the body in groups positioned symmetrically about an axis, and a device for tautening the anchoring lines, said device including two winching systems carried by a rigid carriage arranged to rotate about said axis with the same symmetry as each group and each including at least one winch, each winch having means for detachably connecting it to an anchoring line so that the winching systems can tauten the lines of one group and, after being disconnected from that group can be moved around the axis on the carriage relative to the stoppers for connection with the lines of another group.

In various embodiments, the means for orienting the carriage about the anchoring plane axis consists of at least one set of rolling means attached underneath the carriage and defining a symmetry with reference to the directional axis, of the carriage, said set of rolling means running on at least one circular track about the anchoring plane axis, each one of such tracks comprising a system of attachment to the floating body.

When the orienting or revolving device has to be fully removable after use, to leave all the available space clear, and also so that it can be used on other seaborne bodies, particularly when they are small in size, like buoys, the system of attachment of each circular rolling track to the seaborne body has to be detachable.

In one recommended embodiment, the winching systems are operated by a single driving unit connected to each system by disconnectable transmission gear.

In other embodiments, the winching systems are operated by two driving units, each of which is connected to one winching system by clutch transmission means.

This latter arrangement is particularly useful when a limited area has to be left free on the seaborne body surrounding the winching plane axis, for example when such an area is occupied by the extension of a cylindrical passage or shaft extending through the seaborne body, such as a shaft for handling tubular installations.

In this case, and in an embodiment allowing easy installation and removal in the presence of tubular material, which may be kept in the shaft for lengthy periods, the carriage is formed of two parts, which intersects the circumference of the circular opening.

In one recommended embodiment, designed to make the tautening device as easy to handle as possible, the winching systems each comprise a single winch.

When circumstances require the tautening to function by operation of the winching system on one side of the directional axis of the carriage first, and the winching system on the other side next, the carriage is equipped with a removable stabilizing system to prevent it from overturning on an axis perpendicular to the anchoring plane.

It will be easier to understand the invention from the following description of one of the many possible embodiments, illustrated by the accompanying figures: Figure 1 is a diagram in elevation of part of a floating body which includes a device for tautening anchoring lines.

Figure 2 is a detailed view of the revolving system under the carriage.

Figure 3 is a detailed view of the revolving system, showing the removable stabilizing device to prevent overturning.

Figure 4 is a planar view of a device for tautening anchoring lines, involving double lines.

Figure 5 shows a tautening device, in which each of the two winching systems consists of a single chain pulley.

Figure 6 shows a tautening device, in which each of the two winching systems consists of two chain pulleys.

Figure 7 shows a tautening device in which each of the two winching systems comprises two chain pulleys, positioned round a central passage through the floating body.

Figure 8 shows a removable tautening device for use on buoys.

Figure 9 shows a device with a singlepulley carriage and multiple anchoring lines.

In Figure 1, anchoring lines 1 and 2, are fixed removably to a floating body 3 with positive buoyancy, by means of stoppers 4 and 5 of a type known per se, after passing over supporting and guide pulleys 6 and 7, the mountings 8 and 9 of which are attached to the body 3. In other embodiments, not shown here, the lines run directly through hawse-pipes on the body 3.

The anchoring lines 1 and 2 are located in the plane of Figure 1, which here is an anchoring plane forming part of a set of anchoring planes (such as plane AA1 in Figure 4) centred on a single axis ZZ1, the anchoring plane axis.

The tautening device consists of a combination of a pair of anchoring lines 1 and 2 with two winches 10 and 11. The winches ]0 and 11 are attached to a rigid carriage 12.

Figure 2 shows this carriage 12 equipped with wheels 13, mounted on forks 14 attached to the bottom of the carriage. Wheels 13 run on a track 15, which consists of a circular rail around and concentric with the anchoring plane axis ZZ1; and which is attached to the seaborne body 3. Consequently, the axis of rotation of the carriage 12 is the same as the anchoring plane axis ZZ1 The winches 10 and 11 are each equipped with means for detachably connecting them to an anchorage line. Figure 1 shows how a line itself or an extension runs over a drum on the winch, which is in the form of a chain pulley, the end being stored in a cavity.When the line consists of a chaincable, it can run directly over the chain pulley; when it consists of a wire cable, it has to be attached to a length of chain-cable, possibly detachable, which runs over the chain pulley.

Winches 10 and 11 are linked by respective clutches to a driving unit consisting of a motor 16, equidistant from the two winches 10 and 11.

In the embodiment shown in Figure 1, the carriage 12 contains a cavity 17 concentric to the axis ZZ1. A member 18 is attached to the body 3 and is aligned with the axis ZZl and engages with the carriage 12 in this cavity 17. The engagement of the member 18 in the cavity 17 is such that the resulting connection, allows the carriage 12 to revolve round the axis ZZl and acts to withstand any transverse force and any rotational torque acting along or about an axis perpendicular to ZZl.

The carriage 12 is subjected to such a torque when only one of the winches 10 or 11 is in use.

Figure 2 shows a detailed view of the track 15 and a wheel 13. The diameter of the outer rim 131 of the wheel 13 is greater than the largest diameter of the tread 1311, which is in contact with the track 15. This arrangement allows vertical and horizontal forces to be transmitted to the floating body, though not forces caused by rotational torque acting about the axis ZZ1. With this type of revolving system, the cavity 17 and member 18 are needed if the winches operate separately.

Figure 3 shows a detailed view of the components illustrated in Figure 2 and means for driving the wheel 13, consisting of a motor 13ill' attached to the carriage 12 and to which the wheel 13 is connected through gear-wheels 131V and 13V. Also shown is a wheel 33 on an axis parallel to the axis of the wheel 13, and mounted on the same fork as the wheel 13. The tread 331 of the wheel 33 is in contact with the underside of the upper flange of the rail 15 and eliminates the need for the cavity 17 and member 18 by preventing toppling or overturning of the carriage 12. These lower wheels can be removed easily from the fork of the wheel 13 using suitable leverage devices, so that the carriage can be dismantled and moved.

The anchoring lines as shown in Figure 1, parallel to the plane of the Figure, can be either single or multiple.

Figure 4 shows a plan of a device as illustrated in Figure 1 but having four groups of anchoring lines. Each group comprises two pairs of lines extending in opposite directions in parallel vertical planes A1A11, A2A2l. The planes AlAll, A2A21 are arranged symmetrically with respect to the anchoring plane AA1 which passes through the axis ZZ1. Where each group comprises only two lines extending in opposite directions, the lines will lie in a common vertical plane constituting the anchoring plane which passes through the axis ZZ.

There are two winching arrangements 10 and 11, one on each side of the axis ZZ1, each comprising two winches 101 and 1011, 11l and 1111. Each of these winches is equipped with means of detachable connection to an anchoring line. If the line is a chain-cable, it runs directly over a chain pulley, and if it is a wire cable, it is attached to a length of chain-cable, which runs over a chain pulley.

Each winching arrangement 10 and 11 is linked by a clutch to a driving unit consisting a motor 16, equidistant in Figure 1 from the axes of the winches 10, 101 and 11, 111.

The winches and the motor 16 are attached to a carriage 12, which can revolve on a track 15 as described previously.

Figure 14 shows an anchorage line 1 running over a pulley 6, which is attached by a part 8 to the body 3. After running over the pulley 6, the line passes through a compressor 4; or a stopper.

There are various ways of storing the end of the anchoring line, for example in a well 19.

Various means known per se and not shown here can be used to handle the end of the anchoring line at the beginning and end of each tautening operation.

Figure 5 shows a tautening device in which each of two winches 10, 11 comprises a single chain pulley, located on each side of the anchorage plane axis ZZ1.

The two winches 10 and 11 the driving motor 16 are attached to a carriage 12, which can revolve by means of a system running on a track 15.

Figures 6 and 7 each show a tautening device in which each of two winches comprises two chain pulleys 101 and 1011 and 111 and 1111, each pair carried on a single axle or on two coaxial axles linked by a clutch.

In Figure 6, the two winches and the driving motor 16 are attached to a carriage 12, which can revolve by means of a system, of a type known per se, running on a track 15.

In Figure 7, each of the winches is driven by a separate motor 16a and 16b. These two motors are linked to their winches by clutches of a type known per se (not shown here).

The winching systems and driving motors are attached to a carriage 12; which can revolve by means of a system, of a type known per se, running on a track 15.

In Figure 7, the carriage 12 is traversed by a circular opening on the axis ZZ1, to allow tubular gear or material to extend vertically to a passage through the associated floating body (not shown here). The carriage 12 is formed from two parts 121 and 1211 of similar construction, which can be connected or disconnected along a surface situated in a plane passing through the axis Z,Zl and perpendicular to the anchoring plane.

The connecting surface between the two parts 121 and 1211 of the carriage 12 intersects the circumference of the circular opening, allowing the carriage 12 to be assembled and removed without touching tubular or other equipment installed in the central space.

Figure 8 shows a diagrammatical crosssection of a removable tautening device for a buoy-shaped floating body.

The body 3 of a buoy is symmetrical about the axis ZZ1, is bounded at the top by an upper deck 31 and traversed by as many pairs of hawse-pipes, facing each other symmetrically on each side of ZZ1, as there are pairs of anchoring lines. The two hawsepipes 20 and 21, shown in longitudinal section in this figure, open on to the upper deck 31. Stoppers 4 and 5 are fixed inside these deck openings.

The deck 31 of the buoy 3 carries a removable base 22 for a circular track 15.

The treads 14 of wheels 13, attached to a circular carriage 12, run on this track 15.

Carriage 12 carries two winches 10 and 11, one on each side of the axis ZZ1, driven by a motor 16 placed between them. These winches are positioned so that the throat of each chain pulley matches the opening of one of the hawse-pipes in the deck 31.

The carriage 12 is fitted with at least two rings 23 and 24, to which sling-ropes can be attached to lift and remove the base 22, using a derrick or other handling gear.

The base 22 of the track 15 is fitted with at least two rings 25 and 26, to which slingropes can be attached to lift and remove the base 22, using a derrick or other handling gear.

One recommended method for moving the winching systems consists of connecting the carriage 12 and base 22 together mechanically by some means known in the previous art and not shown here, after detaching the base 22 from the buoy 3, so that carriage and base can be raised together.

Figure 9 shows one recommended embodiment, in which a pair of winches each comprise a single winch or chain pulley. In this case, multiple anchoring lines are tautened in succeeding pairs, beginning in this figure with lines 1 and 2.

As the lines are tautened, the carriage 12 aligns itself by revolving round the axis 7,Zl.

It is advisable to fit protective stops 27, 28, 29, 30 on each side of the hawse-pipe openings. It is also advisable to fit similar stops 31 and 32 on each side of the chain pulley 10 and 11, attached to the carriage 12.

In Figure 9, the carriage revolves on the system illustrated in Figure 2. This is adequate whether the two winches are used together or separately, since the anchoring lines pass inside the circular track 15.

For embodiments in which the lines pass over the outside of the track, e.g. as in Figure 1, the arrangement illustrated in Figure 3 should be adopted.

A device to tauten anchoring lines as described above particularly in the simplest form in which the two winches each include a single chain pulley, offers very obvious advantages.

Using a single such device taking up very little space, it is possible to tauten the different pairs of anchoring lines, then disconnect one of the two lines of a pair to complete tautening of the other, or to perform any other operation.

When the lines anchoring a seabome body have been tautened, the tautening device can be removed, using a derrick or helicopter, and placed on another floating body, to perform the same operations.

This ensures considerable saving in resources, space and time, thereby increasing the economic efficiency of the equipment used.

WHAT WE CLAIM IS:- 1. A floating body provided with a plurality of stoppers arranged to co-operate with anchoring lines which in use are arranged on the body in groups positioned symmetrically about an axis, and a device for tautening the anchoring lines, said device including two winching systems carried by a rigid carriage arranged to rotate about said axis, said winching systems being arrange in use one each side of the axis with the same symmetry as each group and each including at least one winch, each winch having means for detachably connecting it to an anchoring line so that the winching systems can tauten the lines of one group and, after being disconnected from that group can be moved around the axis on the carriage relative to the stoppers for connection with the lines of another group.

2. A floating body according to Claim 1, wherein the carriage is rotatable about the axis on at least one set of rolling means attached underneath the carriage and which run on at least one circular track which constitutes a means of attachment of the device to the body.

3. A floating body according to Claim 2, wherein the means for attaching the device to the body are releasable.

4. A floating body according to Claim 1, wherein the two groups of winches are operated by a single driving unit connected to each group by clutch transmission means.

5. A floating body according to Claim 1, wherein each one of the two groups of winches is operated by a driving unit, each driving unit being connected to a group of winches by clutch transmission means.

6. A floating body according to Claim 1, wherein the carriage supporting the winching systems contains a circular opening centred on the axis of symmetry of the carriage.

7. A floating body according to Clairn 6, wherein the carriage supporting the winching systems and containing the circular opening centred on the axis of symmetry of the carriage is formed of two parts, which can be connected or disconnected along a surface which intersects the circumference of the circular opening.

8. A floating body according to Claim 1, wherein each winching system comprises a single winch.

9. A floating body constructed and arranged substantially as described herein with reference to and as illustrated in Figures 1 to 4, or Figures 5, 6, 7, 8 or 9 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. be attached to lift and remove the base 22, using a derrick or other handling gear. The base 22 of the track 15 is fitted with at least two rings 25 and 26, to which slingropes can be attached to lift and remove the base 22, using a derrick or other handling gear. One recommended method for moving the winching systems consists of connecting the carriage 12 and base 22 together mechanically by some means known in the previous art and not shown here, after detaching the base 22 from the buoy 3, so that carriage and base can be raised together. Figure 9 shows one recommended embodiment, in which a pair of winches each comprise a single winch or chain pulley. In this case, multiple anchoring lines are tautened in succeeding pairs, beginning in this figure with lines 1 and 2. As the lines are tautened, the carriage 12 aligns itself by revolving round the axis 7,Zl. It is advisable to fit protective stops 27, 28, 29, 30 on each side of the hawse-pipe openings. It is also advisable to fit similar stops 31 and 32 on each side of the chain pulley 10 and 11, attached to the carriage 12. In Figure 9, the carriage revolves on the system illustrated in Figure 2. This is adequate whether the two winches are used together or separately, since the anchoring lines pass inside the circular track 15. For embodiments in which the lines pass over the outside of the track, e.g. as in Figure 1, the arrangement illustrated in Figure 3 should be adopted. A device to tauten anchoring lines as described above particularly in the simplest form in which the two winches each include a single chain pulley, offers very obvious advantages. Using a single such device taking up very little space, it is possible to tauten the different pairs of anchoring lines, then disconnect one of the two lines of a pair to complete tautening of the other, or to perform any other operation. When the lines anchoring a seabome body have been tautened, the tautening device can be removed, using a derrick or helicopter, and placed on another floating body, to perform the same operations. This ensures considerable saving in resources, space and time, thereby increasing the economic efficiency of the equipment used. WHAT WE CLAIM IS:-

1. A floating body provided with a plurality of stoppers arranged to co-operate with anchoring lines which in use are arranged on the body in groups positioned symmetrically about an axis, and a device for tautening the anchoring lines, said device including two winching systems carried by a rigid carriage arranged to rotate about said axis, said winching systems being arrange in use one each side of the axis with the same symmetry as each group and each including at least one winch, each winch having means for detachably connecting it to an anchoring line so that the winching systems can tauten the lines of one group and, after being disconnected from that group can be moved around the axis on the carriage relative to the stoppers for connection with the lines of another group.