CA1086183A - System for mooring a vessel, particularly an oil- tanker to an off-shore tower - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A system for mooring a ship or like floating vessel, in particular an oil-tanker, to an off-shore column and for transferring a fluid cargo such as for example, gas, petroleum oil or the like, using articulated arms carried by the head of said column and adapted to rotate about the latter, wherein the improvement consists in that said system comprises at least one arm carried by the said head and connected at its free end to an extensible device carrying a connector device adapted to be secured to a conduit provided on said vessel, said connector device being additionally connected to said head by a hawser.

Description

61~3 The present invention relates to a sys-tem for mooring a ship or like floating vessel, particularly an oil-~anker to an off-shore tower or column, e~ a tower or column fixedly or pivotally mounted on a sea bed or ocean floor, and for transferring a fluid cargo suoh as petroleum oil or the like.
It is known to plaoe on the tower or platform the major part of a sys-tem in-tended to ensure the conneotion between the upper end of the conduit or i~
conduits of the tower, on the one hand, and the conduits of the vessel on the other hand. Such sy~tem~ comprise particularly an arm carried by the platform,but it is always necesgary to provide flexible oormecting pipes between the free endof the a~m a~d the conduits of the vessel.
~he in~ention aims at providing an assembly which i~ entirely rigid, thus avoiding the agency of flexible pipes.
To this end, according to the invention, the systems of the kind in ques-tion comprise at lea3t one arm : pivotally carried by the tower, particularly by the rotating head of the latter, if any, the end of the aaid arm supporting preferably by means of a telescopic or extensible rigid device, a connector sys-tem adapted to be fitted onto a hollow mouth-piece or like'fi-tting head mountedon the vessel and connec-ted to the stationary conduit of the latter.
In such an assembly, any oonduit between the platform and the ves~el oan be carried by the arm and its appended device~. In partioular this oonduit may comprise only rigid element~, possibly common to those of the said arm and to the ~aid appended devioe~, particularly to the extensible or telescopio 3ystem.
Within this tele~oopio system, where such a 3ystem i8 used, the liquid can be made to pass in pipes which also are telescopic, or use can be made of an arrangement capable of being u3ed independently, i.e. of being applied to any fluid connector system, whatèver the general arrangement, in which arrangement the extensible 3ystem carried by the aforesaid arm is designed in the form of ~ucces-sive deformable element~ constitutin~ four-bar linkages,of the pantograph type, at least some of the said elements being hollow to serve a~ passages for the fluid, in combination with ap~ropriate rotary ~oints.
It is under~tood that instead oi a ~ingle arm there can be provided ~eve-ral a~ms interoonneoted by movable ~oints, with mean~ provided at the said mo-vable joints and oontrolled by servo-motors to open or olose their mutual angle ; of incidenoe, this solution allowing the assembly to be ooll~psed, retraoted or folded up on the tower during the period of rest.
~he ~ingle arm, or the first arm from the tower, may be fixedly or pivo-~; ~ tally assembled to the rotatable head of the tower in proximity to the vertioal ;` axis of the latter, or alternatively, it may be pivotally assembled to the end of a horizontal or inolined beam seoured to the said tower or to its rotatable head if any.
As for the mooring proper it oan be perjformed by means of a hawser, one :,, .

end o~ which is attached for example to the aforesaid connector device, therefore to the vessel, once the sa.id device is put in place for the tran~fer o~ the fluid, whereas its other end is attached to a wench or, preferably, to a balance or counter-weight capable of being retracted together with a portion of the hawser into the tower.
As another possible alternative, the hawser can be done away with and use can be made of the arms, especially where several such arms are provided, to support the mooring strain once the connection is performed, in combination with absorbing or damping means maintaining the assembly constituted by the arms and the connector in a predetermined relative position while at the same time allowing a certain resilienc~ to sub-sist in the connection.
It should be noted, in any case, that owing to the presence of extensible or telescopic devices, the structure as a whole, after the connection and the mooring, o~fers possibilities of deEormations, preferably absorbed by the a~ore- `:
said absorbing or damping means, and can there~ore withstand without danger the relative mo~ions of the vessel and the tower under the action of sea heave.
~s for the connector device, it is advanta~eousl~ ob-tained according to an arrangement described in Canadianpatent application S.N. 2~8,53~, ~iled October 12, 1977 in khe name of ENTREPRISE D'EQUIPEMENTS MECANIQUES ET H~DR~ULIQUES
E.M.~I., and in which a device is used comprising on the one hand a hollow body with a centring and guiding cone adapted to operate with the aforesaid mouth-piece or like fitting head and, on the other hand, with a sliding connector element suitably operated to be engaged into the said mouth-piece and thus ensure the connection, in conjunction with packing or sealing means, ~ -2-, ~ . . , . . : ,: , ; , and lastly locking means for maintaining the connecting position.
Lastly, the operation of the various motors or servo-motors or actuators to ensure the necessary movements of the assembly carried by the tower, can be controlled either from the latter or from the vessel itself by radio tra~smission act-ing upon receiver relays associated with the said motors, the latter solution allowing tower personnel to be dispensed with or to be reduced to the necessary number for simple supervision or watching purposes.
Apart from the above arrangements, the invention com-prises some other arrangements, which are used preferably at the same time and which will be referred to more clearly later.
It is more particularly directed to certain forms of application, as well as certain forms of embodiment, of the said arrangements, and it is directed still more particularly and as novel industrial products to systems of the kind considered involving an application of the said arrangements as well as the special elements appropriate to achieve the same, and the assemblies or groups of devices, or specifically the towers or columns and the oil-tankers, comprising such systems and elements.

-2a--6~83 The inven-tion will be better under~tood and other pu~po~es, featurea, de-tail~ and advantages of the latter will appear more olearly from the following explanatory description made with reference to the appended diagr&mmatic drawings given solely by way of ex~mple illustrating one form of embodiment of the in-vention and wherein :
- ~igure 1 is a diagrammatio elevational view, with portions removed, of an assembly constituted by an oil-loading or-~torage power or column, a ve~el and a system for mooring the latter and transferring the oil, the whole asaembly being designed according to the invention ;
- Figure 2 is a diagrammatic top view, to a larger scale, of certain ele-ments of the extensible portion carrying the connector system compri~ed in the said assembly ;
- Figure 3 is a view similar to Figure 1, illustrating another form of embodiment of the invention.
According to the invention and according more specially to its form of application and to the forms of embodiment of its various portions, which seem to deserve preference, considering an off-~hare tower or column, for example a tower 1 (Figure 1), connected to the sea bed or ocean floor either pivotally or not and reoeiving the oil through conduits or lines such as 5, the means for mooring a ship or like floating vessel 6 and ensuring the transfer (in one direo-tion or other dependi~g upon the purpose to be aohieved) of oil be-tween the conduit 5 and another oonduit or line 7 seoured to the vessel are provided as follows or in a similar manner.
Use is made essentially of at least one arm 8 which oan ~e secured onlthe rotary head 9 of tower l,where such a rotary head is provided, or pivotally assembled to the latter, the said arm being of suitable len~th to allow the connection to be performed when the bow of the vessel is loca-ted a ~ultable di~-tanoe from the tower, the free~end of the said arm supporting at 10, preferably through a universal or Cardan joint, a oonneotor devioe C adap-ted to be fitted onto a hollow mouth-pieoe or flttin~ head oonneoted to the end of the fixed oon-duit~ of the ves~el, the oonneo-tion between the Cardan ~oin-t 10 and the saidoonneotor bein~ pref0rably ensured by rigid a~d ex-tensible or telescopio means ~
(Figures 1 and 3) the length of whioh is therefore variable (it being understoodhowever, that the inventionlalso inolude~ the ca~e where the said oonnector is simply pivo-tally oonnected to the said a~m, the latter being pivotally oonneoted to the ro-tary head of the tower).
I-t is under~tood tha-t several arms can be used, for example two axms 81 and 82, one (81) of the latter being pivotally assembled either to the head of the tower or, if suitable and as shown in ~igure 3, to the end of a support beamor ilate 51 rotating together with the said head, whereas the ~eoond arm (82) ishingedly assembled at 10' to arm 81.

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6~33 It i~ al~o under~tood that i the tower i8 not provided wi-th a rotary head, the a~m 8 or 81 may be mounted on the tower ~tationary platform or top in swivelling relationship to the latter.
As for the conduit portions to be provided in thi~ aasembly b~tween the platform, i.e. between the oonduit 5, on the one hand, and the oonnector C, on the other hand, they may be oonstituted by rigid pipes oarried by the struoturesof the said aasembly, the said portions being for example telesoopio or exten-sible within the exten~ible system ~ interoonneoting the oonnector C and the arm 8 or 82 at 10.
However, as ~hown in the drawings, the said extensible means ~ may advanta-geously be constituted by a set or series of artioulated element~ in the nature of pantograph~ or the like, at least some of the articulated elements, in the form of tubes, in oombination with rotary joints, being used to ensure the passage of the liquid between the rotary joint 10 and the oonneotor C.
There is shown in Figures 1 and 2 a form of embodiment of an extensible system of this kind, whioh oomprise~ for example a set of rectilinear elements in the form of rhombuses 11, 12, pivotally oonnected to one another around axes 13 and 141, 142, some (13) of the said axe~ bein~ located along a oentral line AA, on either side of whioh are looated the axes 141, 142 forming the vertioes of the rhombuse~ oonstituted by the imbrioation of two broken lines.
For the sake of simplifioation lt i~ a~sumed in Figures 1 and 2 that only one of the broken lines 11 i~ used to transfer the liquid and i~ aonstituted to this end by hollow elements, with oorresponaing rotary joints at 141, whereas-the other broken line 12 is aonstituted by any conneoting elements jointed at 142.
It i8 understood, however, that both broken-line paths can be used to tran~fer the liquid.
~he assembly of articulated element~ i~ pivotally connected at 10 and 15 to the conduit oarried by the arm 8 and to the inlet of oonneotor C, respeotively.
~he ao-tuation of this artioulabed system or it~ exten~ion or its retraotion 3Q can be performed in an~ appropriate m~nner, for example by means of a oable 32 pa~ing round a pulley 33 and whioh is wound onto or unwound ~rom a winoh 34 operatod by motor 35~
As regards the conneotor C, it is ~ub~tantially oonstituted, as pointed out above, in the manner desoribed in the afore,mentioned patent applioation filed at the same time ae the present applioation, or in any other suitable manner.
Shown diagrammatioally in ~igure 1 are the essential elements of this oonneotor, whioh oomprises for example, in order to co-operate with a mouth-pieoe or fitting head 20 to whioh the oonduit 7 of the vessel leads :
- a hollow body 21 supported by a support pivotally oonnected to the base 4 of the extensible system ~ (or direotly to the arm 8 if such a system is not used) whioh hollow body oan be fitted with an appropriate olearance onto the head -::: : :: : ,,~ ;

~86~3 20 and is provided at ita bottom with a centring cone 23, - a sliding hollow connector element hydraulically connected to the con-duit proceeding from the tower or the exten~ible system T and operated by an actuator to sealingly engage into the outlet passage 24 of the head 20, - and locking means ensuring a stable conneoting posi-tion, e.g. locking pins or the like adapted to co-opera-te with a slot 25 provided on the said head.
~ he assembly can be completed by television cameras 36 carried by the connector sy~tem T and allowing it to be readily located with respect to the vessel during the manoeuvring operation.
The whole of this a~sembly carried by the tower i8 completed by means ensuring the mooring of the ves~el once the connection is accQmplished, the saidmeans compri~ing for example a hawser 26 of the usual type, one end of which, according to an advantageous form of embodiment, can be attached to a ring 27 mounted freely around the body 21 of the connector system C, whereas the other end can be at-tached at a fixed point 52 of the tower (F~gure 1) or to a winch orl preferably, after passing on a guiding pulley 28, to a counter- or balance-weight 29 hanging freely within the tower as shown in Figure 3.
It is al~o po~sible, if suitable, to dispense with the ~aid hawser and to ensure the mooring by means of the ri6id system constituted by the arm or arms such as 8, 81~ 82 and by the oonneotor C. It is suffioient, to this end, to fix this assembly after the oonneo-tion while at the same time allowing for a oertain deformation thereof, in oombination with ~hook-absorbing or damping means.
The presenoe of ~uoh ab~orbing means is always useful sinoe it allows -the whole struoture to follow, owing to the relative dqformations of its various elements but without danger of resonanoe, the relative motion~ of the vessel (rolling, pitohing~ and of the osoillating tower under the aotion of the heave of the sea.
~hus, assuming that use is made, a~ shown is Figure 3, of two a~ms oom-bined with a hawser 26 attaohed (by any suitable means after the mooring position 3 i~ obtained) at one end to the oonneotor and at the other end to the tower, and a~suming also that the relative displaoements of arm~ 81~ 82 aro performed for example by an aotu~tor 31 pl~oed betwe0n two pivot axes 31 and 32~ the absorbing or damping effeot oan be ensured by an oleopneumatio devioe 38 oonneoted to the said aotuator and oomin~ into aotion after the latter has moved both arms to therequired position.
~owever, there oan be provided for the same purpose a ri~id looking of the artioulated assembly and the mouth-pieoe or fitting head 20 oan be oonstituted by a body conneo-ted to the vessel not rigidly as previously but through absorbing or damping means.
4 Con~equently, a ves~21 mooring and oargo transferring assembly is obtained whioh allows all apparatus to be grouped on the platform, but withoub requiring the presence of flexible pipe~, the said assembly being simple to operate and, if suitable, controllable Irom the ves~el (remote radio aontrol). ~he a~embly operates during the mooring as follow~.
Considering for example the form of embodiment of ~igure 1, with a haw~er 26 connected to the oormector system C, before the mooring the latter together with the extensible device T is in retraoted position and the arm 8 i~ oriented in the direotion of the wind.
~ he ve~sel then manoeuvres, in particular by means of a bow thruster 37,so as to move clo~er to, and to assume a position in the vertical plane of, the connector device C.
~hereafter, the extensible system ~ i6 moved downwards by means of the motor 35, this operation being controlled either from the tower by a qualified personnel or preferably directl~ from the ves~el if the latter is equipped with radio means capable of remotely acting on relays controlling the motor 35 as well as the other means of operation of the a~sembly.
Once this operation is over and the hollow body 21 of the conneotor devioe C is fitted on the mouth-pieoe 20 looated on the vessel, the whole arrangement is looked by means of the looking pins co-operatin~ with the slot 25.
~he mooring is then ensured for example by the hawser 26 tensioned by the balanoe-weight 29 (~igure 3).
A ~imilar prooedure is u~ed in the oa~e o the aosembly aooording to Figure 3, the exten~ion of the said a~eembly being en~ured by the aotuator 31 and the motor 35.
Owing to this arrangement, the assembly oan be easily moved to a spaGe-savin~ retraoted idle po~ition.
Lastly, if the plat~orm is not provided with a rotary head, in whioh oase the a~m 8 or 81 is neoessarily mounted direotly on the tower and movablè about a vextioal pivot and pos~ibly also about a horizontal axis, the operating ~teps still remain ~ub~tantially the same, again allowing the presenoa of flexible oonneotin~ pipes to be avoided as muoh as po~sible.
In any oaee, the, invention of:~ers a great many advantages over the already exl0tin~ equipment~ o:~ the kind oon0idered, par-tioul~rly:
- that of ~ubstantially using only elemen-t~ that are rigid and easy to look after, - that of requiring simple operating s-teps, oontrolled from the ve~el bg radio mean~ l:E sui-table, - tha-t o:E ensuring all the neoe~sary aoouraoy of the said operating steps, - that of allowingt by folding the retraotable devioe ~ and, in the ¢ase of two arms, by folding the latter, the whole assembly to be folded up ~o as to 4~ oooupg minimum spaoe, - that of allowing the relative displaoements of the vessel and the tower .

to be ea~ily followed in the mooring po~ition, owing to the u~e 3f the said retractable device and, po~ibly oE movable ioints between the arms in oaoe several arms are u3ed.
Of course, the invention is by no msans limited to the form of embodiment desoribed and illustrated which has been givsn by wag of example~only. In parti-oular, it oomprises all the meano oon~tituting teohnioal equivalents to the mean~ de~oribed as well as their oombinations should the latter be oarried out aooording to its gist and used within -the scope oP the following claim~.

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Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A system for mooring a ship or like floating ves-sel, in particular an oil-tanker, to an off-shore column and for transferring a fluid cargo such as, for example, gas, petroleum oil or the like, from said column to said ship or like floating vessel, comprising at least one arm carried by the head of said column and adapted to rotate about the latter, fluid transfer piping means for coupling the fluid conduits of the column to a conduit provided on said ship, said piping means being supported by said at least one arm, a connector device for coupling said piping means to the inlet of said conduit on said ship, said system including an extensible device which is variable in length, constitutes a part of said piping and extends between the free end of said at least one arm and said connector device, control means for controllably varying the length of said extensible element and a hawser connected by one of its ends to the head of said column and by the other end to said connector device.

2. A system according to claim 1, wherein said exten-sible device is constituted by a series of pivotally intercon-nected four-bar linkages each one being of the pantograph type, at least two bars coupled in series of each said pentograph ele-ment being constituted by tubular elements communicating with one another for forming a tubular passageway through said panto-graph element for the transfer of said fluid cargo to said ship conduit.

3. A system according to claim 1, wherein said head is a rotary head and said at least one arm is adapted to swivel with said rotary head into various angular positions.

4. A system according to claim 1, wherein said control means for said extensible device are constituted by cable means fixed to the end of said device which is coupled to said connector device, said cable means running to a motor driven cable winch mounted onto the said free end of said at least one arm.

5. A system according to claim 1, with at least two articulated arms, one of which is carried by said column head whereas the other carries said connector device, through an ex-tensible device, wherein damping means are provided between said arms to allow the whole set of arms to follow the oscillations of sea heave while ensuring a damping effect preventing resonance phenomena.

6. A system according to claim 5, wherein said damp-ing means are of the oleo-pneumatic type.

7. A system according to claim 1, with at least two articulated arms, one of which is carried by said column head, whereas the other carries the connector device, through an ex-tensible device, wherein between said arms are provided means com-prising an actuator adapted to control the relative variations of the said arms.

8. A system according to claim 1, wherein damping means are provided between said vessel and said mouth-piece in-tended to receive said connector device.

9. A system according to claim 1, including various motors ensuring the displacements of the connector system and of the structure carrying the same said motors being provided with relays adapted to receive radio emissions from said vessel, so that the connection operations can be controlled from said vessel.