Vessel mooring system
First Claim
1. A vessel having a detachable vessel mooring system, said vessel comprising:
- a hull, said hull defining a mooring recess, said recess being situated intermediate the bow and stern of the vessel and being in a wholly submerged portion of said hull;
a buoyant mooring element sized to be situated within said submerged mooring recess;
a plurality of mooring lines extending between and connected to said mooring element and the ocean floor, said mooring lines being arranged so that as said mooring element moves downward from said mooring recess, an increasing amount of each mooring line comes to rest on the ocean floor;
means for securing said mooring element within said mooring recess;
means for permitting the vessel to pivot about the mooring element along a substantially vertical axis;
means for releasing said mooring element from said vessel; and
,said mooring element being adapted to sink upon being released from said vessel to an equilibrium position above the ocean floor at which the buoyancy of the mooring element is balanced by the loading imposed on the mooring element, the loading on said mooring element decreasing with increasing depth due to increasing amounts of said mooring lines resting on the ocean floor.
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Accused Products
Abstract
The disclosure describes apparatus for mooring a vessel 10 in unprotected waters. The vessel 10 contains a recess 34 in its hull adapted for receiving a buoyant mooring element 18. The mooring element 18 is attached to the ocean floor 12 by a plurality of mooring lines 20. Means are provided for releasably securing the mooring element 18 within the recess 34. The buoyancy of the mooring element is established such that on release from the vessel 10 it sinks to a predetermined depth a spaced distance above the ocean floor. The apparatus of the present invention is especially well suited for mooring a hydrocarbon storage tanker proximate the terminus of a production riser in waters subject to ice floes.
128 Citations
36 Claims
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1. A vessel having a detachable vessel mooring system, said vessel comprising:
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a hull, said hull defining a mooring recess, said recess being situated intermediate the bow and stern of the vessel and being in a wholly submerged portion of said hull; a buoyant mooring element sized to be situated within said submerged mooring recess; a plurality of mooring lines extending between and connected to said mooring element and the ocean floor, said mooring lines being arranged so that as said mooring element moves downward from said mooring recess, an increasing amount of each mooring line comes to rest on the ocean floor; means for securing said mooring element within said mooring recess; means for permitting the vessel to pivot about the mooring element along a substantially vertical axis; means for releasing said mooring element from said vessel; and
,said mooring element being adapted to sink upon being released from said vessel to an equilibrium position above the ocean floor at which the buoyancy of the mooring element is balanced by the loading imposed on the mooring element, the loading on said mooring element decreasing with increasing depth due to increasing amounts of said mooring lines resting on the ocean floor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An oceangoing vessel and mooring system therefor, comprising:
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a buoyant mooring element; means for securing said vessel to said buoyant mooring element; a plurality of mooring lines, one end of each mooring line being anchored to the ocean bottom and the other end being attached to said buoyant mooring element, the mooring lines being of a length sufficient that a portion of the mooring line nearest the ocean bottom rests on the ocean bottom when said mooring element is secured to said vessel, the amount of mooring line resting on the ocean bottom increasing as the distance from the ocean bottom to said mooring element is decreased; means for allowing said vessel to pivot relative to at least a portion of said mooring element about a vertical axis; means for selectively releasing said buoyant mooring element from said vessel, the buoyancy of said mooring element being less than the load imposed by said mooring system when said mooring element is secured within said vessel, whereby upon release said mooring element sinks under the loading of said mooring lines, said mooring element buoyancy being established such that an equilibrium position is reached above the ocean floor at which the buoyancy of said mooring element is balanced by the loading imposed on said mooring element at such equilibrium position. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A mooring system for mooring a vessel, comprising:
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a buoyant mooring element adapted to be secured within a recess in said vessel, said buoyant mooring element having an upper portion which is situated at an upper position on said mooring element when said buoyant mooring element being secured to the vessel; means for releasing said mooring element from said vessel; means for permitting said vessel to rotate about a vertical axis while maintaining at least a portion of said mooring element free from rotation; a plurality of mooring lines, one end of each mooring line being anchored to the ocean floor and the other end being attached to said buoyant mooring element, a portion of each mooring line resting on the ocean bottom when the mooring element is secured to said vessel; said mooring element being adapted, upon being released from said vessel, to sink to a predetermined depth above the ocean floor and to remain at that depth; and
,means for ensuring that said mooring element upper portion remains uppermost, relative to said mooring element, while said mooring element is situated at said predetermined depth. - View Dependent Claims (28, 29, 30, 31, 32)
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33. A tanker vessel and system for maintaining said tanker vessel in fluid communication with a production riser, comprising:
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a tanker hull, said hull defining a mooring recess; a plurality of storage areas situated within said hull for receiving fluids; a mooring element adapted to be received within said mooring recess; means for securing said mooring element within said mooring recess; means for permitting said vessel to rotate relative to said mooring element about a substantially vertical axis; a riser of a length sufficient to extend from the ocean floor to said mooring element when said mooring element is positioned within said mooring recess, said riser being adapted to accomodate submergence of said mooring element a preselected distance beneath said mooring recess; means for placing said riser in fluid communication with said tanker storage areas when said mooring element is secured within said mooring recess; a plurality of mooring lines extending from the ocean floor to said mooring element, said mooring lines being adapted to bias said mooring element against substantial lateral motion, each of said mooring lines being adapted to have a lower portion thereof rest on the ocean floor, the amount of said line resting on said ocean floor increasing as said mooring element is submerged an increasing distance beneath said mooring recess; means for releasing said mooring element from said vessel, said mooring element being adapted to submerge upon such release to a preselected depth intermediate the depth of said mooring recess and the depth of said ocean floor, said mooring element being adapted to remain at said preselected depth; and
,means for causing said mooring element to rise from said preselected depth to the level of said mooring recess. - View Dependent Claims (34, 35, 36)
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Specification