GB2207898A - Offshore mooring system - Google Patents
Offshore mooring system Download PDFInfo
- Publication number
- GB2207898A GB2207898A GB08815216A GB8815216A GB2207898A GB 2207898 A GB2207898 A GB 2207898A GB 08815216 A GB08815216 A GB 08815216A GB 8815216 A GB8815216 A GB 8815216A GB 2207898 A GB2207898 A GB 2207898A
- Authority
- GB
- United Kingdom
- Prior art keywords
- mooring system
- mooring
- cylindrical
- arms
- ship
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000002131 composite material Substances 0.000 claims abstract description 15
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- 230000033001 locomotion Effects 0.000 description 9
- 229920005989 resin Polymers 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 239000003365 glass fiber Substances 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 3
- 229920006337 unsaturated polyester resin Polymers 0.000 description 3
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 2
- 229920000271 Kevlar® Polymers 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 2
- 230000005489 elastic deformation Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000004761 kevlar Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 229920002972 Acrylic fiber Polymers 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000001530 fumaric acid Substances 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003032 molecular docking Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- IHQKEDIOMGYHEB-UHFFFAOYSA-M sodium dimethylarsinate Chemical class [Na+].C[As](C)([O-])=O IHQKEDIOMGYHEB-UHFFFAOYSA-M 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- 229920001567 vinyl ester resin Polymers 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B22/00—Buoys
- B63B22/02—Buoys specially adapted for mooring a vessel
- B63B22/021—Buoys specially adapted for mooring a vessel and for transferring fluids, e.g. liquids
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Revetment (AREA)
- Ropes Or Cables (AREA)
Abstract
An offshore mooring system comprising two structural arms (1) made of composite material, which are fixed, by means of cylindrical hinges (2;5), at one end to a body (3) rotatable around a single-point mooring (4) and, at the other end, to a ship and are convergent from each broadside (6) of the ship towards said rotary body. <IMAGE>
Description
OFFSHORE MOORING SYSTEM
This invention relates to an offshore mooring system, made of a composite material.
As is known, with the beginning of offshore oil search and production, the problem of offshore mooring of ships, for example for loading and unloading operations, has been overcome according to solutions such as that described in U.S. patent No. 3,155,069.
U.S. patent No. 3,155,069 describes an offshore mooring system comprising two rigid reticular structures which longitudinally extend along each broadside of a ship. The convergent ends of these structures are fixed to an element rotating around a buoy, while the free divergent ends are connected to the ship through ropes or chains. Furthermore the ship is connected to a floating cylindrical element which rotates around a horizontal axis inserted between the two reticular structures in an intermediate position.
By means of this mooring system the ship can carry out the usual operations such as the loading of crude oil from an offshore oil well, with usual safety margins.
The movements of the ship due to the wave motion or the action of wind, which cause the ship both to rotate (yaw) and to continuously move to and from the mooring buoy, occur freely owing to the presence, in the mooring system, of the above-described rotary element and floating cylindrical element.
However, other movements such as rolling and pitching either cannot occur or can occur only limitedly, as the rigid reticular structures, which longitudinally extend along the ship broadside, prevent such movements due to their stiffness.
These mooring systems require therefore continuous maintenance and checking because the fatigue stress exerted on the rigid elements can lead to fractures thereby involving considerable risks.
Furthermore, since such structures are generally made of steel, they require an anticorrosive protection, which can be avoided by using materials different from steel, such as titanium, which, however, has the drawback of being very expensive.
The present invention provides an offshore mooring system for offshore docking, which comprises two structural arms of composite material which are fixed, by means of cylindrical hinges, at one end to a body rotatable around a single-point mooring and, at the other end, to a ship and are convergent from each broadside of the ship towards said rotary body.
The term "composite material", as used herein, means a thermosetting resin reinforced with organic or inorganic fibres.
The thermosetting resins utilized to construct the mooring system of the present invention are suitably selected from the unsaturated polyester resins or from vinylester, epoxy, polyurethane resins, etc.
Unsaturated polyester resins such as, for example, bisphenolic and isophthalic resins are preferred.
The fibres can be glass fibres, carbon fibres, acrylic fibres, aramidic fibres such as Kevlar, etc.
Kevlar is a Registered Trade Mark. Glass fibres are preferred because they impart to the composite material the optimum elasticity for this type of structure and because of the cost/performance ratio.
Such fibres can be used as such or in the form of fabric. The fibres can be in the form of staple fibres or of continuous monofilaments, arranged at random or, preferably, in tows of unidirectional monofilaments, without solution of continuity and kept together by filaments helically wound around them.
Any fibre/resin weight ratio can be used for the preparation of composite materials to be used in the construction of the offshore mooring system according to the present invention; however the weight ratios preferably employed are those ranging from 80/20 to 20/80 and more preferably from 60/40 to 40/60.
The composite material is prepared according to known techniques by means of automatic or semi-automatic impregnation and deposition systems on pre-existing molds.
The structural arms are preferably cylindrical, and have a length less than 100 m and a diameter less than 5m. More preferably, the cylindrical structural arms having a length from 20 to 70 m and a diameter from 0.2 to 3 m.
Furthermore, the cylindridal arms can be solid or hollow; in the latter case the thickness is generally less than 1 m and more preferably ranges from 0.5 to 50 cm.
The rotary body is preferably a metal table or a table of composite material and pivoted to a single-point mooring as a monolithic single-pile structure of the type described in British patent Nos.
2,102,482 and 2,123,883 or in Italian patent application
Nos. 84,116 A/83 and 19,301 A/86.
By means of the offshore mooring system of the present invention it is therefore possible to dock in the open sea any type of ship, even those exceeding 300,000 tons of dead-weight capacity, without the drawbacks of the previously known mooring systems. In fact, the physico-mechanical characteristics of the composite material are such to allow torsional or flexural elastic deformations of the cylindrical elements which are not obtainable with the rigid reticular structures previously known. Therefore, the typical motions of moored ships, such as pitching, rolling, and yaw, can freely occur both due to the presence of the movable mechanical elements and due to the elasticity of the composite material.
The offshore mooring system of the present invention can be utilized for both the stern-mooring and the head-mooring of ships, does not require the use of mechanical joints or of other movable parts in addition to the ones previously described. which are inserted between the cylindrical elements, and does not not need any anticorrosive continuous treatment.
Furthermore, the mooring system of the present invention is utilizable for the mooring of ships with sea characterized by a considerable wave height Hs up to 18 meters.
The invention will be further described, by way of example only, with reference to the accompanying drawing, which is a schematic horizontal view of an offshore mooring system.
The drawing shows a mooring system suitable for the mooring of a 250,000 gross tonnage ship, in the presence of up to 9 m high waves, the system comprising two tubular elements made of a composite material prepared from glass fibres and from an unsaturated polyester resin obtained from bisphenol A and fumaric acid in a fibre/resin ratio ranging from 40/60 to 60/40. The glass fibres are arranged, in part, parallel to the axis of each tubular element, in the form of continuous monofilament tows, and in part are helically wound around said tows.
The mooring system comprises two cylindrical elements 1 consisting of two pipes having a length of 46 m, an outside diameter of 2 m and a wall thickness of 16 cm. Both pipes are pivoted by means of cylindrical hinges 2 to a table 3 of 6m length rotatable around a single-point mooring 4 described in Italian patent application No. 19,301 A/86.
The free ends of each tubular element are equipped with two cylindrical hinges 5 for connection with the ship broadsides 6 schematically indicated with broken lines.
The cylindrical hinges fixed to the end portions of the tubular elements made of composite material permit rotations around the axes indicated by a, a', b, b' and prevent any other relative motion.
Due to the characteristics of the resulting kinematic motion, the rolling motion of the ship and, in part, the yaw motion, which are due to the wave-motion or to the action of the wind, cause the flexural and torsional elastic deformation of the tubular elements, which the composite material can well withstand.
Claims (9)
1. An offshore mooring system, comprising two structural arms made of a composite material and fixed, by means of cylindrical hinges, at one end to a body rotatable around a single-point mooring and, at the other end, to a ship, said arms being convergent from each broadside of the ship towards said rotary body.
2. A mooring system as claimed in claim 1, wherein the structural arms are cylindrical, and have a length less than 100 meters and a diameter less then 5 meters.
3. A mooring system as claimed in claim 2, wherein the cylindrical structural arms have a length from 20 to 70 meters and a diameter f,rom 0.2 to 3 meters.
4. A mooring system as claimed in any of claims 1 to 3.
wherein the cylindrical arms are solid or hollow.
5. A mooring system as claimed in claim 4, wherein the cylindrical arms are hollow and have thicknesses of less than one meter.
6. A mooring system as claimed in claim 5, wherein the hollow cylindrical arms have thicknesses from 0.5 to 50cm.
7. A mooring system as claimed in any of claims 1 to 6, wherein the said rotary body is a rotatable table made of metal or of composite material.
8. A mooring system according to claim 1, substantially as herein described with reference to, and as shown in, the accompanying drawing.
9. The use of the mooring system claimed in any preceding claim, for the mooring of ships having a gross tonnage even exceeding 300,000 tons with sea characterized by wave-height Hs up to 18 meters.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT21152/87A IT1221933B (en) | 1987-07-02 | 1987-07-02 | MOORING SYSTEM FOR OFFSHORE MOORINGS |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8815216D0 GB8815216D0 (en) | 1988-08-03 |
| GB2207898A true GB2207898A (en) | 1989-02-15 |
| GB2207898B GB2207898B (en) | 1991-11-27 |
Family
ID=11177518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8815216A Expired - Fee Related GB2207898B (en) | 1987-07-02 | 1988-06-27 | Offshore mooring system |
Country Status (5)
| Country | Link |
|---|---|
| AU (1) | AU608019B2 (en) |
| BR (1) | BR8803232A (en) |
| GB (1) | GB2207898B (en) |
| IT (1) | IT1221933B (en) |
| NO (1) | NO882915L (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI42406B (en) * | 1962-08-17 | 1970-03-31 | Bp Tanker Co Ltd | |
| GB2034652B (en) * | 1978-11-14 | 1983-04-20 | Seaflo Systems Nv | Single-point mooring systems |
| FR2507994A1 (en) * | 1981-06-22 | 1982-12-24 | Delamare Guy | DEVICE FOR QUICK MOORING A FLOATING INSTALLATION TO AN ANCREATED MARINE INSTALLATION |
| NL181492C (en) * | 1982-02-01 | 1987-09-01 | Single Buoy Moorings | Mooring device. |
| US4589801A (en) * | 1984-07-16 | 1986-05-20 | Conoco Inc. | Composite mooring element for deep water offshore structures |
| US4602586A (en) * | 1984-12-24 | 1986-07-29 | Exxon Production Research Co. | Motion decoupling mechanism for fluid swivel stack |
| US4665856A (en) * | 1985-10-03 | 1987-05-19 | Sofec, Inc. | Mooring apparatus |
-
1987
- 1987-07-02 IT IT21152/87A patent/IT1221933B/en active
-
1988
- 1988-06-27 GB GB8815216A patent/GB2207898B/en not_active Expired - Fee Related
- 1988-06-30 BR BR8803232A patent/BR8803232A/en unknown
- 1988-06-30 AU AU18560/88A patent/AU608019B2/en not_active Ceased
- 1988-06-30 NO NO88882915A patent/NO882915L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU1856088A (en) | 1989-01-05 |
| BR8803232A (en) | 1989-01-31 |
| AU608019B2 (en) | 1991-03-21 |
| NO882915D0 (en) | 1988-06-30 |
| GB8815216D0 (en) | 1988-08-03 |
| GB2207898B (en) | 1991-11-27 |
| IT8721152A0 (en) | 1987-07-02 |
| NO882915L (en) | 1989-01-03 |
| IT1221933B (en) | 1990-08-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19920627 |