US3919957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Floating structure and method of recovering anchors therefor
Assignee: SONAT OFFSHORE DRILLING Inc
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Filing: 1974-04-15
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Granted: 1975-11-18
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Expires: 1994-04-15
Abstract
Abstract An improved floating structure suitable for use as a floating drilling platform having a tension mooring system of a plurality of anchors each with a depending skirt on its lower side, control passageways through the anchor to the area defined by the skirt, ballasting and deballasting means, and a plurality of cables connecting each anchor to the floating platform, tension monitoring and control devices associated with each cable to assure substantial equalization of tension in the cables, the anchor locking system to secure the anchors to the floating platform, the anchors having a total buoyancy to support the entire weight of the structure so that in transit a minimum structure is below the water, and a plurality of thrusters controlled to assist in accurate station keeping of the floating platform and in movements of the floating structure from and to moored location. The method of recovering the anchors which are connected to the floating platform having at least three legs by cables or chains which includes the steps of ballasting the floating platform to lower it in the water, tightening all of the cables or chains to a uniform tension, deballasting one of the legs of the platform to increase the tension in the connections to one of the anchors and thereby pull the anchor free of the bottom, similarly deballasting the platform to pull the other anchors free of the bottom, and lifting the anchors into engagement with the lower end of its platform leg.
Inventors
- 👤 Donald R Ray
- 👤 James D Bozeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:29
CPC Classifications
B; B63; B63H; B63H25/00; B63H25/42; B63B; B63B1/00; B63B1/02; B63B1/10; B63B1/107; B63B21/00; B63B21/50; B63B21/502; B63B35/00; B63B35/44; B63B35/4413; B63B1/12; B63B2001/128
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
194 words
A floating structure comprising a platform having a deck and at least three vertical hollow legs depeNding below said deck and horizontal members extending between the lower ends of said legs, at least three anchors, each anchor being adapted to be positioned under one of said legs, means for ballasting and deballasting each of said legs, means for connecting said anchors to said platform, means for ballasting and deballasting each of said anchors, and said anchors when deballasted exerting sufficient buoyancy force to support substantially all of said platform above water with only the anchors creating drag resisting movement of the structure in the water, said platform having sufficient buoyancy to exert a tension on the anchor connecting means for each anchor at least equal to the weight of said anchor, said anchors being movable downward from said legs for engagement with the bottom and having said connecting means extending from said anchors to said legs as a plurality of parallel tension lines without any non-parallel lines, said anchor deballasting means being associated with said legs and operative only when said anchor is in close spaced relationship to the lower end of its leg.
Claim 2
Dependent Claim
194 words
A floating structure comprising a platform having a deck and at least three vertical hollow legs depeNding below said deck and horizontal members extending between the lower ends of said legs, at least three anchors, each anchor being adapted to be positioned under one of said legs, means for ballasting and deballasting each of said legs, means for connecting said anchors to said platform, means for ballasting and deballasting each of said anchors, and said anchors when deballasted exerting sufficient buoyancy force to support substantially all of said platform above water with only the anchors creating drag resisting movement of the structure in the water, said platform having sufficient buoyancy to exert a tension on the anchor connecting means for each anchor at least equal to the weight of said anchor, said anchors being movable downward from said legs for engagement with the bottom and having said connecting means extending from said anchors to said legs as a plurality of parallel tension lines without any non-parallel lines, said anchor deballasting means being associated with said legs and operative only when said anchor is in close spaced relationship to the lower end of its leg.
Claim 3
Dependent Claim
17 words
A floating structure according to claim 1 wherein said anchors each include a plurality of watertight segments.
Claim 4
Dependent Claim
46 words
A floating structure according to claim 1 including means associated with said anchors for increasing the short term holding force to a force greater than the anchor weight and reducing said short term holding force to the anchor weight in a relatively short period of time.
Claim 5
Dependent Claim
46 words
A floating structure according to claim 1 including a skirt depending below the bottom of each anchor, and a restricted flow passageway through each anchor to provide controlled relief of the vacuum created under each anchor and within said skirt by continued lifting on the anchors.
Claim 6
Dependent Claim
48 words
A floating structure according to claim 4 wherein said restricted flow passageway is sized to allow substantially complete relief of the vacuum created under each anchor and within said skirt by continuous exertion of a force exceeding the anchor weight in a period of less than 30 minutes.
Claim 7
Dependent Claim
87 words
A floating structure according to claim 1, wherein said anchor connecting means for each anchor includes three mooring lines extending from said platform to said anchor, said mooring lines being positioned parallel to said legs and spaced substantially equally around said legs with one of said mooring lines on each anchor being on the side of the leg facing the remainder of the structure, said lines all being connected to said anchor at points equally spaced around and equidistant from the center of gravity of said anchor.
Claim 8
Dependent Claim
62 words
A floating structure according to claim 6, including a plurality of winches mounted on said platform, said winches being connected to and adapted to pay out and retrieve said mooring lines with each winch connected to only one line and each line having a winch connected thereto, and means for equalizing the tension in each of the mooring lines of each leg.
Claim 9
Dependent Claim
58 words
A floating structure according to claim 7 wherein said tension equalizing means includes each of said winches being movably mounted, an actuator connected to each of said winches, and means supplying actuating fluid to each of said actuators to exert a preselected force on said winches whereby the preselected tension is developed in each of said mooring lines.
Claim 10
Dependent Claim
21 words
A floating structure according to claim 8 including means associated with said winches for sensing the tension in its mooring lines.
Claim 11
Dependent Claim
21 words
A floating structure according to claim 1 including means for releasably locking said anchors to the lower ends of said legs.
Claim 12
Dependent Claim
72 words
A floating structure according to claim 10 wherein said locking means includes a plurality of axially movable locking pins positioned in each leg at an angle to the axis of said leg, said anchor defining a plurality of recesses in alignment with each of said pins, and means for mOving said pins into said recesses and retaining said pins within said recesses to secure each of said anchors to its respective leg.
Claim 13
Dependent Claim
30 words
A floating structure according to claim 1, including a plurality of thrusters mounted on said platform and adapted to extend into the water with the structure floating on said anchors.
Claim 14
Dependent Claim
39 words
A floating structure according to claim 12, including means for orienting each of said thrusters to direct their thrust individually whereby said thrusters assist in the towing of said structure and in station keeping when said structure is moored.
Claim 15
Dependent Claim
54 words
A floating structure according to claim 1 wherein said anchors include a plurality of compartments, and a line extending vertically through each of said compartments being open at its lower end to the interior of the compartment and extending through the upper surface of the anchor and being open thereabove at its upper end.
Claim 16
Dependent Claim
79 words
A floating structure according to claim 1 including a nozzle positioned within each of said legs, each of said anchors defining a deballasting chamber which when said anchors are held against the lower end of said legs is in alignment with said nozzle and so that said nozzle communicates with the interior of said anchor, means for moving said nozzles into communication with its respective deballasting chamber, and means for supplying air to said nozzles to deballast said anchors.
Claim 17
Dependent Claim
28 words
A floating structure according to claim 15 wherein said nozzle includes a flexible section allowing said nozzle to connect with said deballasting chamber even when slightly misaligned therewith.
Claim 18
Dependent Claim
54 words
A floating structure according to claim 15, including means for communicating from said nozzle to atmosphere and to ballast in said leg, and means controlling flow through said communication means whereby water may be directed into said anchor, said anchor may be in communication with said atmosphere and both said communications may be closed.
Claim 19
Dependent Claim
20 words
A floating structure according to claim 15, wherein said air supply means is an air compressor connected to said nozzle.
Claim 20
Dependent Claim
25 words
A floating structure according to claim 15 wherein said nozzle moving means includes at least one double acting actuator to extend and retract said nozzle.
Claim 21
Dependent Claim
140 words
A floating structure comprising a platform having a deck and three vertical hollow legs depending below said deck, three cylindrical anchors, one for each leg, three mooring lines for each leg, each of said legs being connected to its anchor by said mooring lines, said mooring lines being positioned parallel to said legs and spaced equally around said legs with one of said mooring lines being on the side of said legs facing the remainder of the structure, means for releasably securing said anchors to the lower end of said legs, means for ballasting and deballasting each of said legs, means for ballasting and deballasting each of said anchors, means for paying out and retrieving each of said mooring lines and for applying a preselected tension to said mooring lines, and means for equalizing the tension in said mooring lines.
Claim 22
Dependent Claim
140 words
A floating structure comprising a platform having a deck and three vertical hollow legs depending below said deck, three cylindrical anchors, one for each leg, three mooring lines for each leg, each of said legs being connected to its anchor by said mooring lines, said mooring lines being positioned parallel to said legs and spaced equally around said legs with one of said mooring lines being on the side of said legs facing the remainder of the structure, means for releasably securing said anchors to the lower end of said legs, means for ballasting and deballasting each of said legs, means for ballasting and deballasting each of said anchors, means for paying out and retrieving each of said mooring lines and for applying a preselected tension to said mooring lines, and means for equalizing the tension in said mooring lines.
Claim 23
Independent Claim
147 words
The method of recovering anchors in a vertical mooring system in which three anchors are ballasted and resting on the bottom of the body of water and connected by mooring lines to a floating platform on the surface of the water wherein the floating platform has a ballastable leg associated with each anchor including the steps of ballasting the floating platform to lower it in the water, tightening all of the mooring lines connecting the anchors to the floating platform to a uniform preselected tension, deballasting a portion of the platform to increase the tension in the connections to one of the anchors to thereby pull the anchor free of the bottom, deballasting other portions of the platform to pull the other anchors free of the bottom individually, and lifting the anchors upwardly thrOugh the water into engagement with the lower end of their respective platform legs.
Claim 24
Independent Claim
147 words
The method of recovering anchors in a vertical mooring system in which three anchors are ballasted and resting on the bottom of the body of water and connected by mooring lines to a floating platform on the surface of the water wherein the floating platform has a ballastable leg associated with each anchor including the steps of ballasting the floating platform to lower it in the water, tightening all of the mooring lines connecting the anchors to the floating platform to a uniform preselected tension, deballasting a portion of the platform to increase the tension in the connections to one of the anchors to thereby pull the anchor free of the bottom, deballasting other portions of the platform to pull the other anchors free of the bottom individually, and lifting the anchors upwardly thrOugh the water into engagement with the lower end of their respective platform legs.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |