Disconnectable mooring system

• US 5,316,509 A
• Filed: 09/27/1991
• Issued: 05/31/1994
• Est. Priority Date: 09/27/1991
• Status: Expired due to Term

• Current Assignee: SOFEC, Inc. (FMC Corporation)
• Original Assignee: SOFEC, Inc. (FMC Corporation)
• Inventors: Ethridge, Charles O., Boatman, L. Terry, Pedersen, Kristen I., Poranski, Peter F. Sr.
• Primary Examiner(s): Swinehart, Edwin L.
• Application Number:
  US07/767,026
• Time in Patent Office: 977 Days
• Field of Search: 114/230, 114/293, 441/3-5, 166/354, 279/2.01, 279/2.02, 279/2.06, 279/4.07, 279/141
• US Class Current: 441/3
• CPC Class Codes: B63B 2022/028 submerged, e.g. fitting into ship-borne counterpart with or without rotatable turret, or being releasably connected to moored vessel
• CPC Class Codes: B63B 21/508 connected to submerged buoy mooring buoys per se B63B22/02
• CPC Class Codes: B63B 22/023 submerged when not in use container type buoys submerged when not in use, not adapted for mooring a vessel B63B22/28; connected to turret B63B21/508

Abstract

An improved detachable mooring system is disclosed of the kind including a rotatable turret mounted on the vessel and a buoyant spider buoy, secured by mooring legs to the sea floor, which may be selectively connected by means of a hydraulic connector to the bottom of the turret. One improvement relates to apparatus for establishing pre-load tension between a collet flange hub of the spider buoy and a hydraulic powered connector at the bottom of the turret. Another improvement relates to apparatus for remotely sensing the level of pre-load tension in the connector. Another improvement relates to a self-aligning support arrangement for supporting the collet connector to the bottom of the turret. Another improvement relates to an axial load bearing arrangement for supporting the turret with respect to the vessel.

Claims

1. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and hydraulically powered collet connector mounted to the bottom of said turret wherein the improvement comprises,

an extension member coupled to said collet connector selectively latched to said collet flange hub.

means for selectively applying a force to said extension member in a direction away from said collet connector and said collet flange hub such that said extension member moves a distance away from said collet connector, said force on said extension member being coupled to said collet connector thereby creating tension between said collet connector and said collet flange hub, and

means for locking said extension member at said distance away from said collet connector, thereby maintaining said tension between said collet connector and said collet flange hub when said force on said extension member is no longer applied.

2. The system of claim 1 further comprising

means for mounting said collet connector to said turret including a socket ring secured to said bottom end of said turret and a ball ring coupled to said hydraulically powered collet connector, said ball ring supported within said socket ring.

whereby when said collet connector is latched to said collet flange hub of said buoyant mooring element, said ball ring may move within said socket ring, thereby providing self-aligning mounting of said mooring element, when latched to said collet connector, with respect to the bottom of said turret.

3. The system of claim 2 further comprising

means for raising said collet connector to the top of said turret while said vessel is connected to said buoyant mooring element.

4. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and a hydraulic collet connector mounted to the bottom of said turret wherein the improvement comprises

a turret support ring secured to the bottom of said turret, said turret ring having an inwardly facing spherical annular seat, and

a collet connector support ring carried by said collet connector, said collet connector support ring having an outwardly facing spherical annular ball surface such that said outwardly facing surface of said collet connector support ring may rock within said inwardly facing spherical annular seat of said turret support ring.

5. The system of claim 4 wherein the improvement further comprises

means for selectively establishing pre-load tension in said connector assembly, and

means for maintaining said pre-load tension in said connector assembly.

6. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and a hydraulic collet connector mounted to the bottom of said turret wherein the improvement comprises means for raising said collet connector to the top of said turret while said vessel is connected to said buoyant mooring element.

7. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and a hydraulically powered collet connector mounted to the bottom of said turret wherein the improvement comprises

means for selective forcing said connector assembly in an upward direction with respect to the bottom end of said turret, thereby establishing pre-load tension between said collet flange hub and collet connector of said connector assembly, and

means for substantially maintaining said pre-load tension in said connector assembly after it is no longer being selectively forced in an upward direction.

8. The improved system of claim 7 wherein said means for selectively forcing said connector assembly in an upward direction includes

a hydraulic cylinder,

means for mounting said hydraulic cylinder to the bottom end of said turret,

a piston member secured to said collet connector, said piston member having an annular shoulder adapted to move within said cylinder, and

hydraulic fluid means for applying pressurized hydraulic fluid beneath said shoulder of said piston thereby forcing said piston and said collet connector upwardly while forcing said cylinder downwardly with respect to said turret via said mounting means.

9. The system of claim 8 wherein said mounting means includes

a turret support ring secured to the bottom of said turret, said turret support ring having inwardly facing spherical annular seat, and

a cylinder support ring connected to said hydraulic cylinder, said cylinder support ring having outwardly facing spherical annular ball surface such that said outwardly facing surface of said cylinder support ring is carried by said inwardly facing surface of said turret support ring.

10. The system of claim 7 further comprising

means for raising said collet connector to the top of said turret while said vessel is connected to said buoyant mooring element.

11. The system of claim 9 wherein

said cylinder support ring, said hydraulic cylinder said piston member and said collet connector are dimensioned to be free to move axially upwardly within said turret, and the system further comprising

means for raising said hydraulic cylinder, said piston member and said collet connector to the top of the turret, while said vessel is connected to said buoyant mooring element.

12. The system of claim 11 further including means for removably securing said cylinder support ring to said hydraulic cylinder comprising

a groove in the outer surface of said hydraulic cylinder, and

a key removably secured to said cylinder support ring, said key disposed within said groove of mounting said cylinder support ring to said hydraulic cylinder.

13. The system of claim 10 wherein said means of raising said collet connector to the top of said turret while said vessel is connected to said buoyant mooring element includes

a first winch disposed at the top of said turret,

tackle means connected between said first winch and said collet connector, and

means for temporarily connecting said buoyant mooring element to said turret, whereby said collet connector may be raised to a position near the top of said turret for inspection while said vessel is temporarily moored to said buoyant mooring element via said turret.

14. The system of claim 13 wherein said means for temporarily connecting said buoyant element to said turret includes

a second winch and chain jack assembly disposed on said vessel, and

force means connected between said second winch and chain jack assembly said buoyant mooring element for applying an upward force on said buoyant mooring element against the bottom end of said turret.

15. The system of claim 14 wherein said force means includes

an axial passage disposed in said connector assembly, and

a chain having one end connected to said buoyant mooring element, placed through said axial passage of said connector assembly, and having its other end connected to said second winch.

16. The system of claim 8 wherein

said hydraulic cylinder includes an upwardly facing annular surface, and wherein

said means for maintaining said tension includes,

a nut threaded about said piston above said hydraulic cylinder, said nut having a downwardly facing annular surface adapted to engage said upwardly facing annular surface of said hydraulic cylinder, and

means for turning said threaded nut downwardly about said piston and against said cylinder such that said annular surfaces engage each other, thereby substantially locking the upward position of said turret bottom and substantially maintaining said pre-load tension of said connector assembly with respect to said turret.

17. The system of claim 16 wherein said means for turning the nut includes a

hydraulic motor secured to said cylinder, said motor having an output shaft,

gear means connected between said output shaft and said nut, whereby the turning of said shaft of said motor rotates said nut with respect to said cylinder.

18. The system of claim 7 further comprising means for remotely sensing said level of pre-load tension in said connector assembly.

19. The system of claim 8 further comprising

one or more strain gauges disposed in the wall of said piston member,

electrical leads connected to said one or more strain gauges running to a monitoring location of said vessel, and

means at said monitoring location connected to said electrical leads for providing an indication of pre-load tension remaining in said collect connector.

20. An improved detachable vessel mooring system including a vessel having a vertical well which is open to the sea and in which sea water rises to a maximum height within said well which is substantially the same height as the exterior water line of said vessel when said vessel is fully loaded and including a vertically aligned turret rotatably secured to the vessel within the well such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including connection apparatus by which said mooring element is selectively connectable to the bottom of the turret wherein the improvement includes,

an axial load bearing assembly disposed within said well at a position above said maximum height to which water rises in said well;

and

removable coupling means for coupling said turret to said bearing assembly means and for allowing said bearing assembly means to be removed from said well without removing said turret from said well.

21. A detachable vessel mooring system comprising

a vessel having a vertical well which is open to the sea and in which sea water rises to a maximum height within said well which is substantially the same height as a maximum exterior water line of said vessel, when said vessel is fully loaded , said well have a substantially vertical longitudinal axis,

an upper turret support ring mounted within said well above said maximum height,

a vertically aligned turret rotatably supported within said well by an axial load bearing assembly placed between an upper part of said turret and said upper turret support ring,

a disconnectable mooring element and a plurality of mooring lines extending between and connected to said disconnectable mooring element and the sea floor, and

connection means by which said disconnectable mooring element is selectively connected to the bottom of said turret.

22. The system of claim 21 further comprising

a lower turret support ring mounted in said well below said maximum height, and a radial bearing placed between a lower part of said turret and said lower turret support ring for at least partially radially supporting said turret within said well.

23. The system of claim 21 further comprising

a mounting ring secured in said vertical well of said vessel,

an annular elastomeric pad placed between said upper turret support ring and said mounting ring within said well, said elastomeric pad being disposed in planes which are perpendicular to said vertical axis said well.

24. An improved detachable vessel mooring system including a vessel having a vertical well which is open to the sea and in which sea water rises to a maximum height when said vessel is fully loaded and having a turret with a vertical axis aligned with and rotatably secured to the vessel within the well such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a mooring element with a vertical axis and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including connection apparatus by which said mooring element may be selectively connected to the bottom of the turret, and including a turret drive assembly by which said turret may be rotated within said well of said vessel when said mooring element is not connected to said turret wherein the improvement includes

at least two downwardly facing alignment pins disposed at the bottom of said turret with hydraulic means to reciprocate said pins selectively from a retracted position to an extended position below the bottom of said turret, and

at least two receptacle means disposed in a top surface of said mooring element which are adapted to register with and to receive said alignment pins when said mooring element is axially and rotationally aligned with said turret.

25. The system of claim 24 wherein said two receptacle means include first and second slot means arranged on the top face of said mooring element so that if (1) said turret is axially and rotationally aligned with said mooring element said pins can be inserted respectively into said first and second slot means, and if (2) said turret is axially aligned with said mooring element but rotationally misaligned with said mooring element by less than a predetermined angular rotation, one of said two pins can be inserted into one of said slot means but not the other.

26. The system of claim 24 wherein

said pins include first and second pins diametrically spaced from each other on opposite sides of a circle of a predetermined radius centered on said turret axis, and

said receptacles of said mooring element are angular slots having radial widths adapted to receive said pins, said slots formed on a circle of said predetermined radius centered on said axis of said mooring element, said slots formed on first and second angular arcs of said circle and having respective first ends which are substantially one hundred eighty degrees from each other measured along one portion of said circle, said slots having respective second ends which are substantially less than one hundred eighty degrees from one another.

27. The system of claim 25 further comprising

powered bumper means secured to the bottom of said turret for forcing the top of said mooring element away from the bottom of said turret when only one of said pins is inserted within one of said first end second slot means so that said turret may be rotated with respect to said mooring element by said turret drive assembly.

28. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and a hydraulic collet connector mounted to the bottom of said turret wherein the improvement comprises

a which and chain jack assembly disposed on said vessel,

a cable connected between said which and chain jack assembly and said buoyant mooring element for applying an upward force on said buoyant mooring element against the bottom end of said turret, and

means for raising said hydraulic collet connector to a position toward the top of said turret, whereby said vessel may be typically moored while said collet connector may be inspected.

29. The system of claim 28 further comprising means for establishing pre-load tension in said connector assembly.

30. The system of claim 28 further comprising self-aligning support means for mounting said collet connector to said bottom of said turret.

31. The system of claim 29 further comprising self-aligning support means for mounting said collet connector to said bottom of said turret.

32. An improved detachable vessel mooring system including a vessel having a vertical well which is open to the sea and in which sea water rises to a maximum height when said vessel is fully loaded and having a vertically aligned turret rotatably secured to the vessel within the well such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including connection apparatus by which said mooring element may be selectively connected to the bottom of the turret, wherein the improvement includes

annular elastomeric pad means secured to said vessel within said well at a position above said maximum height within said well, and

bearing assembly means mounted on said elastomeric pad means for axially supporting said turret to said vessel within said well while allowing said hull and said turret to rotate with respect to each other, wherein said bearing assembly means includes

a support ring secured to said annular elastomeric pad means,

a bearing race secured to said support ring,

a thrust assembly supported by said vessel bearing race, and

removable connection means for removably connecting said turret to said bearing, wherein said removable connection means includes

an annular shoulder provided about an outer surface of said turret, said shoulder having a shoulder outer diameter.

a bearing retainer ring connected to said bearing, said retainer ring having an inner diameter greater than said shoulder outer diameter, and

a shear key ring means removably disposed between said bearing retainer ring and said annular shoulder for (a) coupling said turret to said bearing assembly via said retainer ring when said shear key ring is in place between said bearing retainer ring and said annular shoulder and for (b) decoupling said turret to said bearing when said key ring is removed between said bearing retainer ring and said annular shoulder, thereby providing clearance of said outer diameter of said turret by said bearing retainer ring and allowing said bearing to be raised upwardly for inspection, maintenance, or replacement.

33. The improved mooring system of claim 32 wherein said annular elastomeric pad means includes a plurality of elastomeric pad spaced about an annular surface of a support assembly fixed to said well.

34. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and a hydraulically powered collet connector mounted to the bottom of said turret, said mooring element having a line axially aligned with said collet flange hub, said collet flange hub and said collet connector having an axial passage adapted for passage through it of a line for pulling the top of said mooring element against the bottom of said turret, wherein the improvement comprises

said line is a chain,

said mooring element having a chain locker means disposed beneath said collet flange hub for storing said entire chain when said chain is not in use during installation of said mooring element to said turret,

wherein a bottom end of said chain is connected to a bottom end of said chain locker means, and a top end of said chain having a buoyant messenger line having one end thereof connected to said top end of said chain,

wherein when said mooring element is not connected to said turret, said messenger line has one end floating on the sea surface with its other end connected to said top end of said chain.

35. The improved mooring system of claim 34 further comprising,

storage means secured to said collet connector for storing said messenger line when said mooring element is connected to said turret.

36. The system of claim 35 wherein said storage means is a funnel shaped housing having an axial passage way through which said chain may be pulled during installation of said mooring element to said turret.

37. An improved detachable vessel mooring system including a vessel having a vertically aligned turret rotatably secured to its hull such that said hull and turret may rotate with respect to each other with the bottom end of said turret facing downwardly toward the sea and including a buoyant mooring element and a plurality of mooring lines extending between and connected to said mooring element and the sea floor and including a selectively operable hydraulic connector assembly having a collet flange hub mounted at the top of said mooring element and a hydraulically powered collet connector mounted to the bottom of said turret wherein the improvements comprises;

means for selectively forcing said connector assembly in an upward direction with respect to the bottom end of said turret, thereby establishing pre-load tension between said collet flange hub and collet connector of said connector assembly; and

means for substantially maintaining said pre-load tension in said connector assembly after it is no longer being selectively forced in an upward direction.