WO2009043383A1

WO2009043383A1 - Floating system and method to operate the same

Info

Publication number: WO2009043383A1
Application number: PCT/EP2007/060570
Authority: WO
Inventors: Patrick Janssens; Michel Bouckaert; Michaël NAERT
Original assignee: Exmar N.V.
Priority date: 2007-10-04
Filing date: 2007-10-04
Publication date: 2009-04-09

Abstract

An offshore liquefied gas regasification facility including a jetty (4) with a liquid pipeline (7) thereon, a mobile floating unit (1) attached to the jetty by a detachable mooring line (5) and having a regasification plant (6) thereon, at least one line handling system (10) on said floating unit with a mooring line (3, 3', 3', 3'') for connection to at least one anchor point (2) designed to withstand severe weather conditions, said regasification plant having an inlet coupling means (8, 9) for connection to said pipeline and an outlet coupling means (8, 9) for connection to a gas pipeline.

Description

Floating system and method to operate the same

Field of the invention

The present invention relates to floating systems with particular mooring system.

More particularly the invention relates to (but is not limited to) floating systems for the regasification of liquefied gas such as liquefied natural gas (LNG) .

Specifically the invention relates to a floating system including a floating platform with at least one unit thereon, said floating platform comprising at least one coupling means of said floating system to a jetty ; and at least one mooring line to move said platform from an operating position to a safe position away from said jetty.

Background of the invention

World natural gas consumption is rising faster than that of any other fossil fuel. About two-thirds of the increase in gas demand is in the industrial and power generation sectors, while the remaining one-third is in space heating of buildings and homes. Recent technological improvements in the design, efficiency, and operation of combined cycle gas turbines have tilted the economics of power generation in favour of natural gas. With the demand for electricity constantly increasing the demand for natural gas can be expected to increase even further. As is the case with oil, natural gas is unevenly distributed throughout the world. More than one-third of the world' s gas reserves are in the territory of the Former Soviet Union. The second largest gas reserve is located in the Middle East. However, North America accounts for more than one-half of the world gas consumption. The United States alone consumes about 2.4 tcf (6.8 10¹⁰ m³) more natural gas per year than it produces. Germany and Japan also import large amounts of natural gas each year. Thus, natural gas frequently needs to be transported from its production locations to the consumption locations. However, the low density of natural gas makes it more expensive to transport than oil. A section of pipe in oil service can hold 15 times more energy than when used to transport high pressure gas. An alternative method of natural gas transportation is by ships. While natural gas can be piped in a gaseous state, it needs to be liquefied so that it may be economically transported by ships. When natural gas is supercooled to minus 162⁰C, it becomes liquid, and takes up only 1/60 Oth as much space as gas. Liquefaction makes it practical to ship natural gas in large volumes, using specially designed ships that maintain the cargo's ultra-low temperature. Once liquefied natural gas (LNG) is transported to its destination, it is converted into gas at a regasification terminal before it is sent to the consuming end. Thus, regasification terminals are important links in the natural gas supply chain.

Most regasification units in operation are located at onshore terminals. An onshore LNG regasification terminal typically consists of a pier or jetty, storage tanks, and regasification plants. An LNG ship comes and berths at the pier and off-loads its cargo of LNG to storage tanks which keep the gas in the same liquid state as they are transported. LNG in the storage tank is later regasified at the regasification plants to produce natural gas which is then transferred to end users through pipelines.

To date, most LNG regasification facilities have been built onshore. However, public concern about safety has caused the gas industry to look for remote sites for such facilities. One alternative is to build the regasification facility offshore. Most of these offshore designs are based on large floating barges installed to permanent mooring systems .

An offshore liquefied gas regasification facility is disclosed in WO-02/095284 (assigned to EXMAR OFFSHORE COMPANY) . This known offshore liquefied gas regasification facility typically comprises a floating platform or barge, attached to a mooring system, this platform having a regasification plant thereon. This regasification plant typically includes tanks for the storage of liquefied gas and a regasification unit which is adapted to regasify this liquefied gas, this unit being connected to a gas pipeline to transfer the regasified gas to onshore facilities. Carriers with liquefied gas normally approach and berth the floating platform and offload their cargo into the storage tanks of the floating platform (see figure 4 of WO 02/095284) .

In shallow water, a floating unit is typically moored to a shore jetty.

Such mooring system is designed to operate within a well defined weather window. In case the weather forecast exceeds the operational weather window for that location, e.g. hurricane or typhoon warning, the mooring is disconnected and the floating unit is moved to a safe location.

In case of a floating regasification facility, this relocation requires disconnection of said mooring lines and said one or multiple coupling means. Hence, operations are stopped yielding operational downtime.

Relocation of the floating unit requires external assistance, e.g. tug boats, which is complicating logistics and lengthening the required time between "decision to abandon operating position" and "being in position on safe location". In areas where tug boats are scarce, especially in anticipation of storm weather, the logistics become problematic and will result in too much operational downtime . In deeper water, offshore, a safe location is normally not available in the vicinity. Hence the possibility for relocation of the floating unit would result in too much operational downtime, if not impossible. Therefore the mooring system in deeper water, offshore, is generally permanent and designed to operate and survive the most severe storm conditions which can be expected at the mooring site. Hence there is no need for disconnection and relocation within the lifetime of the unit.

Such mooring system must of course be adapted to suffer and survive severe storm conditions and is therefore expensive .

Further, in case of a floating regasification facility, a permanent mooring system in deeper water without jetty requires a complex and expensive cargo transfer system between the shuttle liquified gas carrier and the regasification facility. Also the flexible connection to the send-out gas pipeline on the seabed and the subsea pipe to shore are expensive.

Summary of the invention It is an object of this invention to overcome the limitations of the floating system of the prior art, relatively to severe weather conditions, exceeding the normal operational weather conditions, in order to minimise operational downtime. It is more particularly an object of this invention to provide an improved floating liquefied gas regasification facility which is less expensive than the offshore liquefied gas regasification facilities operating in deeper water of the prior art and which is nevertheless adapted to avoid detrimental effects of severe weather conditions.

Another object of this invention is an improved method to operate a floating liquefied gas regasification facility according to the invention, in normal operational weather conditions and in weather conditions which exceed normal operation weather conditions.

The aim of this invention lies in the application of an mooring system, with survival capability relative to severe weather conditions, to a floating unit in the presence of a shore jetty for cargo transfer. The floating unit has two distinct operation modes:

1. Operational condition: the floating unit is moored to a shore jetty with disconnectable mooring lines.

2. Survival condition: the floating unit is moored at a safe distance from the jetty with survival capability relative to severe weather conditions, meaning that the floating unit can move freely without hitting the jetty.

The transition between operational and survival condition is preferably achieved without external assistance such as tug boats. As such there is minimum downtime of operations in case relocation of the floating unit is required.

Accordingly, the floating system according to the invention, include a mobile floating platform with at least one unit thereon, said platform comprising at least one coupling means of said floating sytem to a jetty; and at least one mooring line for connection of the floating platform to at least one anchor point outside said platform; said jetty is located away from said anchor point and comprises at least one flow line for joining to said at least one coupling means of said floating system; - said at least one mooring line is attached to a line handling system which can be a winch, a jack or similar, which is located on said platform and which is designed to move said platform from an operating position at said jetty to a safe position away from said operating position.

In particular, the object of the invention is a floating system as described in the sub-claim.

Most preferably, the floating system is a liquefied gas regasification facility including a floating platform and a regasification plant thereon. This floating unit is not critical for the definition of the invention and may generally include a large platform, such as a barge or similar. Alternatively a retrofitted or converted LNG carrier may be used for this floating unit.

The regasification plant is provided with an inlet coupling means for the connection of this plant (generally storage tanks of this plant) to an offloading line of a liquefied gas carrier. Details on this offloading line will be apparent later.

In the regasification plant the liquefied gas, discharged from a carrier, is regasified and is thereafter offloaded from this plant into a gas network connected to gas users. Therefore the regasification plant of the facility according to the invention is provided with an outlet coupling means to a gas pipeline (usually an underwater pipeline) connected to this network. Details on this outlet coupling means will be apparent later. In the regasification facility according to the invention the floating unit must be moored and it comprises for this end at least one mooring line for connection to at least one anchoring point which is generally located on the sea bed or sea floor. In this specification "mooring line" and "anchor point" are generic expressions. A mooring line may generally include either one single cable attached to one single anchorage means or a bundle of a plurality of cables attached to a plurality of anchorage means. By anchorage means, it is understood that it preferably comprise an anchor point which may be an anchor point on the sea bed or alternatively a buoy which is connected to an anchor point on the sea bed.

The cable may for example consist of chains, steel wires, ropes or combination thereof. In one embodiment of this invention the floating unit comprises one single mooring line connected to one single anchor point. This anchor point may be an anchor point on the sea bed or alternatively a buoy which is connected to an anchor point on the sea bed. In this embodiment the floating unit will be allowed to weathervane around this fixed anchored point. In this specification, this embodiment will be denoted "single point mooring".

In another embodiment of this invention the floating unit comprises more than one mooring line and more than one anchor point. For example in this another embodiment three (preferably four) mooring lines may be provided for connection respectively to three (respectively four) anchor points anchored in the sea bed. Advantageously four mooring lines may be provided at four quarter of a substantially rectangular floating unit, these four mooring lines being attached to four anchor points on the sea bed. In this specification, this embodiment will be denoted "spread mooring". The floating system of this invention comprises a jetty. It may be a floating offshore jetty. It is preferably a fixed jetty anchored in the sea bed. The jetty is designed to be berthed by a carrier in order to have a liquefied gas cargo offloaded from this carrier into storage tanks of the aforesaid regasification plant. The jetty has at least one flow line and according to preferable embodiments, the jetty has multiple pipelines thereon, which are preferably cryogenic.

In case of regasification facility, the at least one flow line comprise in particular at least one liquid loading pipeline (inlet) , at least one vapour return line (outlet) and at least one high pressure send-out gas line (outlet) . By "Liquid pipeline", it is meant a pipeline which is specifically adapted for the transfer of a liquid fluid, more particularly a liquefied gas. The liquid pipeline of the jetty forms part of the aforesaid offloading line for the transfer of the liquefied gas cargo of the carrier into the tanks of the regasification plant. This pipeline is not critical per se.

According to the invention the jetty is located away from the aforesaid anchor point. The expression "away from the anchor point" will be clarified later in this specification.

According to a particular embodiment of the invention, the system further comprises at least one detachable connection mooring line which is designed to connect and attach the floating unit to the jetty when the jetty is in a position close to the jetty. "A position close to the jetty" denotes a usual operational position of the floating unit allowing a normal operational offload of a liquefied gas cargo from a carrier into storage tanks of the aforesaid regasification plant using the aforesaid liquid pipeline of the jetty. For this end the connection mooring line may be provided on the floating unit and adapted to be detachably connected to the jetty. Alternatively said connection mooring line may be provided on the jetty and adapted to be detachably connected to the floating unit. In another embodiment said connection mooring line is adapted to be detachably connected to both the jetty and the floating unit .

An object of this invention is to allow the floating unit to be moved away from the jetty towards a safe position in which the floating system, in particular the regasification facility suffer substantially no risk to be damaged in case of severe weather conditions in the vicinity of the jetty (such as storms, typhoon or hurricanes) . More specifically an object of the invention is to allow the floating unit to be moved away from the jetty towards said safe position when the weather forecast in the vicinity of the jetty exceeds the operational weather window.

Advantageously, in the floating system according to the invention, said at least one mooring line, said at least one anchor point and said line handling system must be selected by one skilled in the art, to allow such moving of the floating unit from said operating position "at the jetty" into said safe position "away from the jetty" without, external assistance such as a tug boat.

In one of the preferred embodiment where the floating system is a regasification facility, the aforesaid at least one flow line advantageously comprises inlet coupling means which are detachable connecting means. Any suitable detachable connecting means of the art may be used.

Similarly aforesaid at least one flow line preferably comprises outlet coupling means which are detachable connection means connecting the floating regasification facility to the jetty. Any suitable detachable connection means of the art may be used.

Preferably, the inlet and outlet coupling means comprise flexible risers. A convenient flexible riser is disclosed in WO 02/095284.

Alternatively the regasification facility according to the invention may advantageously be provided with a removable gangway between the floating unit and the jetty to allow somebody to access easily from the floating unit to the jetty and vice-versa.

In a particular embodiment of this invention said at least one mooring line comprises a plurality of mooring lines which are respectively attached to a plurality of anchor points outside the floating unit and to a plurality of line handling systems, (winches or jacks or similar) which are located on the floating unit. Preferably this embodiment comprises four mooring lines which are attached respectively to four line handling systems and to four anchor points. More preferably the four line handling systems are located at the four angles of a quadrilateral figure (advantageously a rectangle) on the floating unit.

The floating liquefied gas regasification facility according to one preferred embodiment of the invention is generally adapted to the regasification of any liquefied gas. It is specifically adapted to the regasification of liquefied industrial or natural gas comprising hydrocarbon particularly to liquefied petroleum gas and to liquefied natural gas .

The invention relates also to a method to operate a floating system, in particular a liquefied gas regasification facility on a water surface. Accordingly the method according to the invention comprises in case of a definite operational weather window : a. operating said line handling system of said at least one mooring line in order to move said mobile floating unit to said position close to said jetty; b. preferably mooring said floating unit to said jetty by means of detachable connection mooring line; and c. connecting said inlet and outlet coupling means of said regasification plant to said pipelines located on said jetty; and in case of weather forecast exceeding said operational weather window : d. disconnecting said inlet and outlet coupling means from said liquid pipeline; e. detaching said detachable connection mooring line in order to unmooring said mobile floating unit from said jetty; and f . operating said line handling system of said at least one mooring line in order to move said mobile floating unit away from said position close to said jetty. In the method according to the invention "water surface" denotes either a lake or more generally a sea or an ocean. Brief description of the drawings

Details and features of the present invention will become apparent to those skilled in the art from the following detailed description of preferred embodiments of the floating liquefied gas regasification facility according to the invention in the light of the accompanying drawings.

Figure 1 is a schematic plan view of a first embodiment of the regasification facility according to the invention, in an operational position; Figure 2 is a schematic plan view of the regasification facility of figure 1 in a safe survival position;

Figure 3 is a schematic plan view of another embodiment of the regasification facility of the invention in an operational position; and Figure 4 is a schematic plan view of the regasification facility of figure 3 in a safe survival position.

In these figures same reference numerals denotes same components .

Detailed description of preferred embodiments

In figure 1 the reference numeral 1 designates a floating platform. This floating platform may generally be a large barge or similar and has a liquefied gas regasification plant 6 thereon. The barge 1 is substantially rectangular, having longitudinal sides 13 and lateral sides 14. It is of the type "single point mooring" defined hereabove. For this end it is moored to a buoy 2 or alternatively to an anchor point on the seabed by a single mooring cable 3. This mooring cable 3 is wound on a winch 10 on barge 1. The barge 1 is in a position close to a jetty 4 and is attached to this jetty 4 by a pair of mooring cables 5. The barge 1 is disposed relatively to the jetty 4 so as to have a lateral side 14 thereof adjacent to the jetty. The barge 1 is retained in this position by tensile stress on the mooring cables 5. When the barge is moored to the jetty by the cables 5, cables 3 can be maintained slack. The mooring cables 5 are detachable cables. This means that they may be detached from the jetty 4 to render the barge 1 free from the jetty 4. The jetty 4 is of a type well known in the art of offshore jetty. It includes a platform or a plurality of interconnected platform on posts anchored in the sea bed.

The regasification plant 6 is of a type well known in the art and commonly used for the regasification of liquefied natural gas. Typically it comprises storages tanks (not shown) and a regasification unit (not shown) .

The jetty 4 comprises a liquid loading line 7 (inlet), one vapour return line 15 and one high pressure send-out gas line 16 (outlet) thereon. The inlet and outlet lines (7, 15, 16) are connected to the regasification plant 6 by means of inlet and outlet coupling means 9, 17 and 18 and by means of inlet and outlet ducting 8, 19 and 20.

Other winches (not represented) , either on the floating platform (1) or on the jetty (4) shall be used to tighten both cables 5, thus having the barge or floating platform 1 substantially fixed, close to the jetty 4 in the operating position. A removable gateway (not shown) joins the barge 1 to the jetty 4 to allow an operator to move from barge 1 to jetty 4 and vice-versa. When operating the regasification facility represented on figure 1, a marine carrier containing a cargo of liquefied gas (for example natural gas) approaches and berths the jetty 4. Thereafter the cargo of liquefied gas is offloaded from the carrier into the tanks of the regasification plant 6, through the pipeline 7, inlet coupling means 9 and duct 8. Similarly, the excess vapour in the cargo tanks of the regasification plant 6 is offloaded from the regasification plant 6 to the jetty 4 through outlet duct 19, outlet coupling means 17 and pipeline 15. Similarly, the high pressure send-out gas of the regasification plant 6 is offloaded from the regasification plant 6 to the jetty 4 through outlet duct 20, outlet coupling means 18 and pipeline 16. In case of weather forecast exceeding the operational weather the inlet and outlet coupling means 9, 17 and 18 are detached to disconnect the ducting 8, 19 and 20 from the pipelines 7, 15 and 16 and both cables 5 are disconnected. The winch 10 is then operated to wind cable 3 thereon and translate the barge 1 toward the buoy 2.

The mooring system of the buoy 2 is designed to withstand and survive the severe weather conditions.

Figure 2 shows the barge 1 in a position close to the buoy. When in this position the barge 1 is allowed to weathervane around the buoy in storm survival position without any risk of hitting the jetty 4.

In case the weather has returned to normal conditions within the defined operational weather window, the floating platform 1 is returned to its original position moored to the jetty 4. This operation is done by connecting one messenger line (not represented) between the floating platform 1 and the jetty 4. This can be done with a small boat such as a crew boat, workboat or rescue boat. Those boats are not considered as being external assistance; they form part of the floating unit and/or jetty operational equipment. By heaving in this messenger line, the floating platform 1 is moved from its survival position at a safe distance from the jetty 4 to the operational position moored to the jetty 4.

In the embodiment of figure 3 the barge 1 is of the type "spread mooring" defined hereabove. For this end it is spread moored via four cables 3, 3' , 3" and 3"' which are attached respectively to four anchor points 2 located on the sea bed. Each cable 3 is wound on a winch 10 located on the barge 1. The four winches 10 are disposed at the four angle of the barge which is substantially rectangular.

It is to be understood that each cable 3, 3', 3", 3'" represented in figures 3 and 4 can be replaced by multiple mooring lines, for example by 2 ou 3 chains or cables in each angle of barge 1.

In the embodiment of figure 3 the barge is in an operating position close to the jetty as defined hereabove with respect of figure 1. The barge is maintained fixed is this position by tightening the detachable connection 5 or alternatively by tightening the cables 3" and 3'" with the cables 3 and 3' slack or loose.

In fig 2 to 6, the inlet and outlet systems have been simplified but it is to be understood that the system can be the same as explained for fig 1. In case of weather forecast exceeding the operational weather conditions the coupling means 9 is detached to disconnect the duct 8 from the pipeline 7 and both cables 5 are disconnected. The four winches 10 are then operated to unwind and loosen both cables 3" and 3"' and to wind and tighten both cables 3 and 3' . The barge 1 is thus moved away from the jetty 4 and moored to a location which is far enough to avoid that the barge 1 hit the jetty 4 and therefore withstand the severe weather conditions (storms or hurricanes or typhoons or the like) is substantially inexistent. Figure 4 shows the barge 1 is such a safe position .

Figure 5 shows a modified embodiment of the one of Figure 1 described hereabove. In the embodiment of figure 5, the barge 1 is disposed relatively to the jetty 4 so as to have a longitudinal side 13 thereof adjacent the jetty. The barge 1 is retained in this position by tensile stress on both mooring cables 5 and on two additional mooring cables 11 attached respectively to two mooring dolphins 12 which are disposed on either side of the jetty and which are anchored in the sea bed. Both mooring cables 11 are detachable cables which may be detached from both mooring dolphins 12.

In case of weather forecast exceeding the operational weather the coupling means 9 is detached to disconnect the ducts, from the pipeline 7 and cables 5 and 11 are disconnected. The winch 10 is then operated to wind cable 3 thereon and translate the barge 1 toward the buoy 2 as explained with respect to the embodiment of figures 1 and 2. The barge can be brought back from safe position to operating position as explained hereinabove for embodiment of fig 1.

Claims

1. A floating system including a mobile floating platform (1) with at least one unit (6) thereon, said platform (1) comprising at least one coupling means (9, 17, 18) of said floating system to a jetty (4); and at least one mooring line (3, 3' , 3", 3"' ) for connection of the floating platform (1) to at least one anchor point (2) outside said platform (1);

Wherein - said jetty (4) is located away from said anchor point (2) and comprises at least one flow line (7, 15, 16) for joining to said at least one coupling means (9, 17, 18) of said floating system; said at least one mooring line (3, 3' , 3", 3"' ) is attached to a line handling system (10) which is located on said platform (1) and which is designed to move said platform (1) from an operating position at said jetty (4) to a safe position away from said operating position.

2. Floating system according to claim 1, comprising furthermore at least one detachable connection mooring line (5) provided for connecting said platform (1) to said jetty (4) when said platform (1) is in said operating position.

3. Floating system according to claim 1 or 2 wherein said at least one unit (6) is an industrial unit.

4. Floating system according to claim 3, wherein said industrial unit (6) comprises a plant for the regasification of liquefied gas.

5. Floating system according to any one of claims 1 to 4, wherein said at least one anchor point comprises at least one buoy (2) .

6. Floating system according to any one of claims 1 to 4, wherein said at least one anchor point (2) is anchored on the sea floor.

7. Floating system according to any one of the preceding claims comprising one single mooring line (3) and one single anchor point (2) .

8. Floating system according to any one of claims 1 to 6, wherein said at least one mooring line comprises several mooring lines (3, 3', 3", 3"') which are respectively attached to a plurality of anchor points (2) outside the platform (1) and to a plurality of line handling systems (10) which are located on the platform (1) .

9. Floating system according to claim 8, wherein said plurality of line handling systems comprises four line handling systems (10) which are located on said platform (1) forming a quadrilateral figure, in particular a rectangle .

10. Floating system according to any one of the preceding claims, wherein said at least one mooring line (3, 3' , 3", 3"' ) consist of chains, steel wires, ropes or combination thereof.

11. Floating system according to claim 2, wherein said detachable mooring line (5) consist of chains, steel wires, ropes or combination thereof.

12. Floating system according to any one of the preceding claims, wherein said at least one flow line comprises a liquid loading line 7 (inlet) , a vapour return line 15 and a high pressure send-out gas line 16 (outlet) ; the said lines (7, 15, 16) being connected to the regasification plant 6 by means of inlet and outlet coupling means 9, 17 and 18 and by means of inlet and outlet ducting 8, 19 and 20.

inlet coupling means 9, one vapour return outlet coupling means 17 and one high pressure send-out outlet coupling means 18, adapted to be detachably connected, one liquid loading duct 8 (inlet), one vapour return duct 19 (outlet) and one high pressure send-out duct 20 (outlet) to said at least one flow line (7, 15 and 16) on the jetty (4) .

13. Floating system according to the preceding claim wherein said at least one coupling means (9, 17, 18) comprises in particular a flexible riser.

14. Floating system according to any one of the preceding claims, comprising in addition at least one removable gangway between said platform (1) and said jetty (4) .

15. Floating system according to any one of claims 4 to 11, for regasification of a liquefied gas comprising at least one hydrocarbon, in particular selected amongst natural gas and petroleum gas.

16. A liquefied gas regasification facility including a mobile floating platform (1) with a regasification plant (6) thereon, said platform (1) comprising at least one coupling means (9, 17, 18) of said regasification plant (6) to a jetty (4) ; and at least one mooring line (3, 3' , 3", 3"' ) for connection to at least one anchor point (2) outside said platform (1); wherein - said jetty (4) is located away from said at least one anchor point (2) and comprises at least one flow line (7, 15, 16) for joining to said at least one coupling means (9, 17, 18) of said regasification plant ; - said at least one mooring line (3, 3' , 3", 3"' ) is attached to a line handling system (10) which is located on said platform (1) and which is designed to move said platform (1) from an operating position at said jetty (4) to a safe position. 17. A method to operate a floating system according to any one of claims 1 to 13 on a water surface, which comprises in case of a definite operational weather window : a. operating said line handling system (10) of said at least one mooring line (3, 3' , 3", 3"' ) in order to move said mobile floating platform (1) to said position close to said jetty (4); and b. connecting said at least one coupling means (9, 17, 18) of said floating system to said at least one flow line (7, 15, 16) on jetty (4); and in case of weather forecast exceeding said operational weather window : c. disconnecting said at least one coupling means

(9,

17, 18) from said at least one flow line (7, 15, 16) on the jetty (4); and d. operating said line handling system (10) of said at least one mooring line (3, 3' , 3", 3"' ) in order to move said mobile floating platform

(1) from an operating position at said jetty (4) to a safe position away from said operating position .

18. A method to operate a floating system according to any one of claims 1 to 13 on a water surface, which comprises in case of a definite operational weather window : a. operating said line handling system (10) of said at least one mooring line (3, 3' , 3", 3"' ) in order to move said mobile floating platform (1) to said position close to said jetty (4); a bis. mooring said platform (1) to said jetty (4) by means of said at least one detachable connection mooring line (5); and b. connecting said at least one coupling means (9,

17, 18) of said floating system to said at least one flow line (7, 15, 16) on jetty (4); and in case of weather forecast exceeding said operational weather window : c. disconnecting said at least one coupling means (9, 17, 18) from said at least one flow line (7, 15, 16) on the jetty (4); and c bis disconnecting said at least one detachable connection mooring line (5); and d. operating said line handling system (10) of said at least one mooring line (3, 3' , 3", 3"' ) in order to move said mobile floating platform (1) from an operating position at said jetty (4) to a safe position away from said operating position.