U.S. patent application number 10/486180 was filed with the patent office on 2004-11-25 for anchor line installation method and connector for use in said method.
Invention is credited to Macrae, Michael, Perratone, Rene.
Application Number | 20040231579 10/486180 |
Document ID | / |
Family ID | 8180759 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040231579 |
Kind Code |
A1 |
Macrae, Michael ; et
al. |
November 25, 2004 |
Anchor line installation method and connector for use in said
method
Abstract
The invention relates to an anchor line installation method
comprising the steps of: connecting the anchor line (2) to the
seabed with an anchoring device (4), providing an anchor line part
(7) on the floating structure (3), picking up the free end of the
anchor line (2) with an installation vessel (1), providing a first
connector element (10) on the free end of one of the anchor line
(2) and the floating structure anchor line part (7), either prior
or after picking up said free end, providing a second connector
element (12) on the other of the anchor line (2) and the floating
structure anchor line part (7), extending a pulling line (8)
between the second connector element (12) and the installation
vessel, the pulling line being engaged on the installation vessel
(I) with the first connector element (10), lowering the first and
second connector elements (10, 12) in the water, from the
installation vessel (I), and hauling in the pulling line (8) with a
pulling device (13) on the installation vessel (I), thereby
connecting the first and second connector elements (10, 12) below
water 20 level, in the upper half of the total water depth. The
installation method allows attachment of pre-installed anchor
liner, to floating constructions without the use of complex
fairleads, chainstoppers and winches on board of the floating
construction. Installation can be carried out below water level at
increased levels of safety.
Inventors: |
Macrae, Michael; (Ville
France Sur Mer, FR) ; Perratone, Rene; (Menton,
FR) |
Correspondence
Address: |
Young & Thompson
Second Floor
745 South 23rd Street
Arlington
VA
22202
US
|
Family ID: |
8180759 |
Appl. No.: |
10/486180 |
Filed: |
July 7, 2004 |
PCT Filed: |
August 6, 2002 |
PCT NO: |
PCT/EP02/08796 |
Current U.S.
Class: |
114/293 |
Current CPC
Class: |
F16G 15/00 20130101;
B63B 21/50 20130101; B63B 21/20 20130101; B63B 2021/505
20130101 |
Class at
Publication: |
114/293 |
International
Class: |
B63B 021/24 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2001 |
EP |
01202972.4 |
Claims
1. Method of connecting an anchor line (2) to a floating structure
(3), comprising the steps of: connecting the anchor line (2) to the
seabed with an anchoring device (4), providing an anchor line part
(7) on the floating structure (3), picking up the free end of the
anchor line (2) with an installation vessel (1), providing a first
connector element (10) on the free end of one of the anchor line
(2) and the floating structure anchor line part (7), either prior
to or after picking up said free end, providing a second connector
element (12) on the other of the anchor line (2) and the floating
structure anchor line part (7), extending a pulling line (8)
between the second connector element (12) and the installation
vessel, the pulling line being engaged on the installation vessel
(1) with the first connector element (10), lowering the first and
second connector elements (10, 12) in the water from the
installation vessel (1), and hauling in the pulling line (8) with a
pulling device (13) on the installation vessel (1), thereby
connecting the first and second connector elements (10, 12) below
water level, preferably in the upper half of the total water
depth.
2. Method according to claim 1, the first connector element (10)
comprising a housing (17) with a receiving opening (19), an
attachment member (31) for connecting to the anchor line (2), an
outlet opening (25, 30) in a side wall, and a deflecting member
(16) for deflecting the pulling line (8) entering the first
connector element (10) via the inlet opening (19) from an axial
direction to a transverse direction to the outlet opening (25,
30).
3. Method according to claim 2, the first connector element (10)
comprising a blocking member (29) for allowing movement of the
second connector element (7') within the housing (17) in the
direction of the pulling force (T) on the pulling line (8), and
blocking movement of the second connector element (7') in a
direction opposite to the pulling force (T) on the pulling line
4. Method according to claim 3, the second connector element
comprising a chain section (7').
5. Method according to claim 2, the first connector element (10)
comprising a resilient locking pawl (18, 18', 27) movable in the
transverse direction, or a recess in the inner housing wall, the
second connector element (12) comprising a plug member with a
recess (20) on its circumference for engaging with the locking pawl
(18, 18', 27) of the first connector element (10), or a resilient
locking pawl for engaging with the recess of the first connector
element.
6. Method according to claim 1, wherein the first connector element
(10) is attached to the anchor line (2), the second connector
element being on one side attached to the anchor line (7) of the
floating structure and on the other side to a rope or wire pulling
line (8).
7. Method according to claim 1, the anchor line (2) comprising a
rope or wire anchor line, the anchor line (7) of the floating
structure comprising a chain.
8. Method according to claim 7, wherein the anchor line (2) has not
been pre-tensioned, a predetermined pulling force being exerted on
the pulling line (8) for causing an elongation of the anchor line
(2).
9. Method according to claim 1, wherein the anchor line part (7) is
connected to the floating structure (3) without a fairlead.
10. Method according to claim 1, a wherein the anchor line part (7)
is connected to the floating structure (3) without a being
connected to a winch on the floating structure.
11. Connector (10, 12) for use in the method according to claim 1
having a housing (17) with on a front side a receiving opening
(19), on a rear side an an attachment member (31) for connecting to
an anchor line, axially aligned with the inlet opening, an outlet
opening (25, 30) in a side wall, a guide wheel (16) placed in the
outlet opening (25, 30) and having an axis (26) transverse to the
axial direction, for deflecting a pulling line (8) or anchor line
(7') entering the connector housing (17) via the inlet opening (19)
from an axial direction to a transverse direction to the outlet
opening (25, 30).
12. Connector according to claim 11, wherein the guide wheel (16)
is rotatable around the axis (26).
13. Connector according to claim 11, wherein the guide wheel (16)
comprises a chain wheel, a resilient pawl (29) being pivotably
mounted on a transverse axis (32) between a blocking position
engaging with a chain link upon pulling a chain (7') in the housing
(17) in a direction from the outlet opening (30) to the inlet
opening (19), and abutting against a blocking member (33) for
preventing movement of the pawl (29) and the chain (7') toward the
inlet opening (19), and a release position by pivoting towards the
outlet opening (30) to be substantially spaced away from the chain
(7') in the connector housing (17).
14. Connector according to claim 12, wherein the guide wheel (16)
comprises a chain wheel, a resilient pawl (29) being pivotably
mounted on a transverse axis (32) between a blocking position
engaging with a chain link upon pulling a chain (7') in the housing
(17) in a direction from the outlet opening (30) to the inlet
opening (19), and abutting against a blocking member (33) for
preventing movement of the pawl (29) and the chain (7') toward the
inlet opening (19), and a release position by pivoting towards the
outlet opening (30) to be substantially spaced away from the chain
(7') in the connector housing (17).
Description
[0001] The invention relates to an anchor line installation method
in which a pre-installed anchor line is attached to a floating
construction such as a barge, a floating production storage and
off-loading system, a semi-submersible platform, a
loading/off-loading buoy or any other floating construction, which
needs to be connected to the seabed.
[0002] From GB-2 258 852 it is known to connect a semi-submersible
platform to a pre-installed anchor leg by attaching the end part of
the pre-installed anchor leg to a temporary floating device via a
pendant line. Upon hook-up, the end part of the anchor line is
picked-up by the anchor handling vessel and is brought together
with the end part of the anchor line section depending from the
platform. On the anchor handling vessel, connection of the anchor
line part of the platform with the anchor line part extending from
the seabed is effected, for instance via a triple connection
device.
[0003] From U.S. Pat. No. 4,067,282 an anchoring method is known in
which the anchor handling vessel picks-up the end of a
pre-installed anchor line and of an anchor line part attached to
the bow of a vessel and attaches both anchor lines on deck of the
handling vessel.
[0004] Finally, from U.S. Pat. No. 4,889,065 a method for
pre-tensioning an anchor line near the seabed is known by
horizontally tensioning said anchor line against an opposite anchor
line on the seabed which carries at its end part a chain stopper.
The chain of the first anchor line is pulled horizontally through
said chain stopper by an anchor handling vessel and vertically
upwards to the winch of the handling vessel, thereby effecting a
substantially horizontal pre-tensioning of the anchor lines near
the seabed,
[0005] The anchor lines of the known floating constructions are
connected via an articulated fair lead/chainhawse/chainstopper
combination and to a large winch on deck for pulling in the anchor
line to achieve the correct tensioning. When the anchor line has
the correct tension, the chain part at the top of the anchor line
is fixed in position by the chain stopper, which is normally placed
above the chain hawse or in integrated with the chain hawse design.
In an alternative installation method, the pre-installed anchor
line has been pre-tensioned by the winch on the anchor installation
vessel,
[0006] The use of winches for tensioning to the anchor lines on the
floating structure is relatively complex and expensive as chain
winches or chain jacks with capacities of several tons are very
expensive equipment. Furthermore, the combination of
fairleads/chainhawse/chainstop- pers is relatively complex.
[0007] It is an object of the present invention to provide a rapid
and cheap anchor line connection method.
[0008] It is an further object of the present invention to provide
in an anchor line connection method in which no
fairleads/chainhawse/chainstopp- er and winches at the anchored
floating structure need to be used for tensioning the anchor
lines.
[0009] It is again an object of the present invention to provide an
anchor line installation method with which polyester mooring legs
can be installed without pre-tensioning.
[0010] It is furthermore an object of the present invention to
provide a connector for use in the method.
[0011] Thereto, the method according to the present invention
comprises the steps of:
[0012] connecting the anchor line to the seabed with an anchoring
device,
[0013] providing an anchor line part on the floating structure
[0014] picking up the free end of the anchor line with an
installation vessel,
[0015] providing a first connector element on the free end of one
of the anchor line or the floating structure anchor line part,
either prior to or after picking up said free end,
[0016] providing a second connector element on the other of the
anchor line or the floating stricture anchor line part, a pulling
line extending from the second connector element to the
installation vessel,
[0017] engaging the pulling line on the installation vessel with
the first connector element,
[0018] lowering the first and second connector elements in the
water from the installation vessel, and
[0019] connecting the pulling line to a pulling device on the
installation vessel, and hauling in the pulling line, thereby
connecting the first and second connector elements below water
level, in the upper half of the total water depth.
[0020] The invention is based on the insight of using the winch
present on the anchor line installation vessel for making the
connection between the pre-installed anchor leg and the anchor line
part of the floating structure. In contrast to the known anchor
line installation method, the connector elements of the present
invention are not connected on deck of the vessel but below water
level. After one connector part has been connected to the other
anchor line part on deck of the installation vessel, via a pulling
line, the connector part is then put overboard. During pulling in,
the pulling line is pulled through the connector element until the
second connector element reaches the first connector element
establishing mechanical connection. During pulling in of the
pulling line, the anchor lines and the pulling lines are in the
same vertical plane and a final mating and connection between the
anchor lines part takes place in the water.
[0021] By the method of the present invention, the need for
separate fairleads/chainhawses/chainstoppers and winches on the
floating structure is obviated. The hook-up of all mooring legs can
be carried out rapidly and effectively according to the method of
the present invention. Furthermore, the new installation method
allows a rapid exchange of damaged mooring lines or mooring lines
which are past their service life. Connecting the connecting
elements below water level results in an increased level of safety
in case one of the highly tensioned anchor lines becomes undone or
the connection fails. Furthermore, connecting the anchor lines
below water level, in contrast to connection of the anchor lines on
board of the vessel, results in improved force transmission from
the winch on the vessel as such a winch and cable guide elements
are laid out to handle large loads in a vertical direction. Hence,
the method of the present invention can be carried out at an
increased level of safety.
[0022] In a first embodiment the connector comprises a housing with
a receiving opening, an attachment member for connecting to the
anchor line, an outlet opening in a side wall, and a deflecting
member for deflecting the pulling line entering the first connector
element via the inlet opening from an axial direction to a
transverse direction to the outlet opening.
[0023] In another embodiment the housing comprises a chainstopper,
the second connector element being formed by a chain section. In an
alternative embodiment, the housing comprises a resilient locking
pawl movable in the transverse direction, or a recess in the inner
housing wall, the second connector element comprising a plug member
with a recess on its circumference for engaging with the locking
pawl of the first connector element, or a resilient locking pawl
for engaging with the recess of the first connector element. The
use of a chainstopper allows applying a varying tensioning on the
connected anchor lines.
[0024] Some embodiments of an anchor line installation method and
connector for use in said method will be explained in detail by way
of example with reference to the accompanying drawings. In the
drawings;
[0025] FIG. 1 shows a schematic three-dimensional bottom view of
the installation method of the present invention;
[0026] FIG. 2a detail of the interconnected anchor lines shown in
FIG. 1;
[0027] FIG. 3a shows a side view of the connector elements of FIG.
2;
[0028] FIG. 3b shows a perspective detail of the connector element
of FIG. 2;
[0029] FIG. 4a-4f show the different steps of the anchor line
connection method of the present invention;
[0030] FIG. 5 shows an embodiment of a connector of the present
invention; and
[0031] FIG. 6 shows a preferred embodiment of the connector of the
present invention.
[0032] FIG. 1 shows an anchor handling vessel or installation
vessel 1 attaching an anchor line 2 to a floating construction 3.
The anchor line 2 is connected via an anchor 4 to the seabed 5 and
has been pre-installed. The free end 6 of the anchor line 2 may be
provided with a marker buoy floating at the water surface to be
picked up by the installation vessel 1. An anchor line part 7
connected to the floating structure 3 is also picked up by the
vessel 1 and is connected to a pulling line 8. The anchor line 2 is
at its free end 6 provided with a first connector element 10
through which the pulling line 8 extends. The connector element 10
may be provided after picking up the anchor line 2 at the marker
buoy or may be connected upon pre-installation of the anchor line
2, i.e. during hook up of the anchor line to the seabed 5. The free
end 11 of anchor line 7 is provided with a second connector element
12 (see FIG. 2) the end of which is attached to the pulling line 8.
By hauling in the pulling line 8 using the winch 13 on installation
vessel 1, the connector element 12 is mated with the connector
element 10 such that both anchor lines 2 and 7 are connected below
water level.
[0033] As can be seen from FIG. 2, the anchor line 2 is at its free
end 6 provided with a chain part 14. The anchor line 7 consists of
chain links with at the end thereof the connector element 12.
[0034] As can be seen from FIG. 3a, the connector element 10
comprises a deflecting member 16 such as a stationary or rotatable
wheel deflecting the pulling line 8 from an axial direction to a
substantially vertical direction.
[0035] As can be seen from FIG. 3b, the housing 17 of the connector
10 comprises resilient pawls 18, 18' which upon introduction of the
connector 12 into the inlet opening 19 of the connector 10 lock
into a circumferential recess 20 on the surface of connector
12.
[0036] FIG. 4a schematically shows the fist step of hook-up of
anchor lines 2 and 7 according to the present invention. The
installation vessel 1 approaches the floating structure 3 with the
free end of the anchor line 2 secured to its deck. The connector
element 10 is attached to the free end of anchor line 2 and the
pulling line 8, which is wound around winch 13, is looped around
deflecting member 16 from an outlet opening in the side wall of the
housing 17 to the inlet opening 19. The free end 22 of the pulling
line 8 is secured to the deck of the installation vessel 1. On the
floating structure 3, the anchor line part 7 has been attached with
at its free end to the connector 12.
[0037] As can be seen in FIG. 4b, the connector 10 is lowered into
the water until sufficient slack is achieved in anchor line 2 for
the vessel 1 to approach the floating structure 3 sufficiently
close for the anchor line part 7 and the connector 12 to be
transferred to the deck of the installation vessel 1. Thereafter,
as can be seen in FIG. 4c, the connector 12 is attached to the end
part 22 of the pulling line 8 which is thereafter hauled in and
wound on winch 13 as shown in FIG. 4d. By pulling in pulling line
8, and lowering connector 12 into the water, the anchor lines 2 and
7 are tightened and are connected as shown in FIG. 4e by connector
12 mating with connector 10. In the final step, the pulling line 8
is severed from the vessel 1 such that the final mooring
configuration shown in FIG. 4f is reached
[0038] FIG. 5 shows an embodiment of the connectors 10 and 12. The
connector 10 is attached to the anchor line 2 via shackle 31. The
connector 10 comprises a hollow cylindral housing 17 into which the
pulling cable 8 is introduced into the inlet opening 19 and exits
through an outlet opening 25 in a side wall of the housing 17. The
pulling cable 8 is guided around deflecting wheel 16, which is
mounted on a transverse axle 26. A resilient locking ring 27
penetrates the wall of the housing 17 to engage with a recess 20 on
the connector 12. Upon mating of the recess 20 with the locking
ring 27, the connector 12 is fixedly connected within the housing
17.
[0039] FIG. 6 shows a side view and a top view of a preferred
embodiment wherein the connector 10 comprises a sprocket 16 around
which the chain 7 is guided. A chain stopper 29 allows movement of
the chain 7 in the direction of the arrow T whereas movement in the
opposite direction is blocked. The chain stopper 29 can pivot
around transverse axis 32 between the release position and a
vertically reoriented blocking position. The chain stopper 29
comprises a central slit through which the vertically directed
chain links can pass, but which is narrower than the width of the
transversely directed chain links. At the rear end, the connector
10 is provided with a connecting shackle 31 for attachment to the
chain 2. The end part 7' of the chain 7 exits through an outlet
opening 30 in the housing 17 in the direction of the installation
vessel and is attached to the pulling line 8. By pulling the chain
in the direction T via the pulling line 8, the tension in the
anchor lines 2 and 7 can be adjusted.
[0040] In the anchor line installation procedure shown in FIG.
4a-4f, it is possible to use the connector shown in FIG. 6. In that
case, the second connector 12 can be formed by the end chain part
7' of the anchor line 7. Hence, it is possible that no separate
connector means are present and that the end section 7' of anchor
chain 7 is used to be passed through the connector housing 10 and
to be attached via chain stopper 29. It is in that case also
possible to not use a separate pulling line 8', but to use the end
part 7' of the chain 7 by connecting said chain to the winch
13.
[0041] It is also possible to exchange the positions of first and
second connectors 10 and 12 in FIG. 4a-4f.
* * * * *