US3872679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for reducing the forces on extendible legs of a floating vessel
Assignee: Chevron USA Inc
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Filing: 1973-12-21
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Granted: 1975-03-25
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Expires: 1993-12-21
Abstract
Abstract Semi-submersible legs are embodied as close-ended cylinders or other similar shapes or combination of shapes having the capability to be ballasted or made buoyant. The semi-submersible legs are connected to a jack-up drilling vessel so that they slide vertically through the vessel deck into the underlying body of water and are lockable at any position along their vertical path. The method of their use requires lowering the extendible main supporting legs of a jack-up drilling vessel above the ocean floor, lowering the semi-submersible legs into the water, making them buoyant so as to cause the vessel to raise out of the water to a distance above probable wave action at which time the extendible main support legs are lowered to a supporting position onto or into the ocean floor. With the extendible supporting legs in a supporting position, the semi-submersible legs are retracted; if the extendible legs penetrate a soft bottom, the semi-submersible legs are first ballasted to serve as an additional jacking down source for the supporting legs and then retracted and deballasted. The foregoing steps are reversed when the drilling vessel is to be relocated with or without the supplemental steps of making the semi-submersible legs additionally buoyant and or lowering the vessel hull to the water surface thus providing an extra lift force on the support legs. The vessel hull is jacked up on the buoyant support of the semisubmersible legs prior to completely removing the extendible main legs from the ocean floor penetration or surace contact.
Inventors
- 👤 William Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:37
CPC Classifications
E; E02; E02B; E02B17/00; E02B17/02; E02B17/021; E02B2017/0056
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
99 words
In a vessel adapted to float on a body of water comprising: a platform; a plurality of passages through said platform; a plurality of main supporting legs operatively and adjustably connected to said platform; means permitting said main legs to have controlled movement through a first set of said passages; semi-submersible leg means operatively and adjustably connected to said platform for providing sufficient buoyancy to raise and support the combined weight of said vessel above the surface of said water while said main legs are moved into a supporting position in contact with the underwater bottom for said platform.
Claim 2
Dependent Claim
99 words
In a vessel adapted to float on a body of water comprising: a platform; a plurality of passages through said platform; a plurality of main supporting legs operatively and adjustably connected to said platform; means permitting said main legs to have controlled movement through a first set of said passages; semi-submersible leg means operatively and adjustably connected to said platform for providing sufficient buoyancy to raise and support the combined weight of said vessel above the surface of said water while said main legs are moved into a supporting position in contact with the underwater bottom for said platform.
Claim 3
Dependent Claim
40 words
The vessel of claim 1 including a jacking means for raising and lowering said platform on said supporting main legs in conjunction with the buoyant force of said semi-submersible legs when said main legs are in a platform supporting position.
Claim 4
Dependent Claim
13 words
The vessel of claim 1 wherein said semi-submersible means are adjustably buoyant legs.
Claim 5
Dependent Claim
71 words
The vessel of claim 1 wherein said semi-submersible leg means consists of four semi-submersible legs operatively and adjustably connected to said platform; a means permitting said semi-submersible legs to have controlled movement through a second set of said passages; said semi-submersible legs providing sufficient buoyancy to raise and support the combined weight of said vessel above the surface of said water while said main legs are moved into a supporting position.
Claim 6
Dependent Claim
34 words
The vessel of claim 3 wherein said means for lowering and raising said semi-submersible legs is controlled ballasting in conjunction with a jack in order to decrease and increase the buoyancy of said legs.
Claim 7
Independent Claim
124 words
A method of reducing destructive forces on a set of supporting main legs of a vessel floating on a body of water while said main legs are lowered into a position in contact with the underwater bottom comprising the steps of: lowering into said water a set of supporting main legs to a position above said underwater bottom so as to avoid contact with said underwater bottom; extending a semi-submersible controllably buoyant means operatively and adjustably connected to said vessel into said body of water; increasing the buoyancy of said means to raise said vessel to a predetermined height; positioning said main legs into a platform supporting position in contact with said underwater bottom; and retracting said semi-submersible controllably buoyant means to said vessel.
Claim 8
Independent Claim
124 words
A method of reducing destructive forces on a set of supporting main legs of a vessel floating on a body of water while said main legs are lowered into a position in contact with the underwater bottom comprising the steps of: lowering into said water a set of supporting main legs to a position above said underwater bottom so as to avoid contact with said underwater bottom; extending a semi-submersible controllably buoyant means operatively and adjustably connected to said vessel into said body of water; increasing the buoyancy of said means to raise said vessel to a predetermined height; positioning said main legs into a platform supporting position in contact with said underwater bottom; and retracting said semi-submersible controllably buoyant means to said vessel.
Claim 9
Dependent Claim
28 words
The method of claim 5 including ballasting said main legs before said main legs are lowered; and making said main legs buoyant after said main legs are lowered.
Claim 10
Independent Claim
139 words
A method of reducing destructive forces on a set of main supporting legs of a vessel floating on a body of water while said main legs are lowered into a position in contact with the underwater bottom comprising the steps of: lowering into said water a set of supporting main legs to a position above said underwater bottom; extending a semi-submersible controllably buoyant means operatively and adjustably connected to said vessel into said body of water; increasing the buoyancy of said means to raise said vessel to a predetermined height; positioning said main legs into a platform supporting position in contact with said underwater bottom; ballasting said semi-submersible means so as to add additional jacking force to said main legs and serve as a load test on said main legs; retracting said semi-submersible means; and deballasting said semi-submersible means.
Claim 11
Independent Claim
139 words
A method of reducing destructive forces on a set of main supporting legs of a vessel floating on a body of water while said main legs are lowered into a position in contact with the underwater bottom comprising the steps of: lowering into said water a set of supporting main legs to a position above said underwater bottom; extending a semi-submersible controllably buoyant means operatively and adjustably connected to said vessel into said body of water; increasing the buoyancy of said means to raise said vessel to a predetermined height; positioning said main legs into a platform supporting position in contact with said underwater bottom; ballasting said semi-submersible means so as to add additional jacking force to said main legs and serve as a load test on said main legs; retracting said semi-submersible means; and deballasting said semi-submersible means.
Claim 12
Dependent Claim
28 words
The method of claim 7 including ballasting said main legs before said main legs are lowered; and making said main legs buoyant after said main legs are lowered.
Claim 13
Independent Claim
115 words
A method of reducing destructive forces on a set of supporting main legs of a jacked up vessel located over a body of water while said main legs are raised into a stowed position comprising the steps of: extending a semi-submersible controllably buoyaNt means operatively and adjustably connected to said vessel into an underlying body of water; increasing the buoyancy of said means to support said vessel at a predetermined height; raising from said water bottom a set of supporting main legs to a predetermined height above said bottom; lowering said vessel to said water surface; retracting said semi-submersible means to said vessel; and retracting said main legs into a stowed position on said vessel.
Claim 14
Independent Claim
115 words
A method of reducing destructive forces on a set of supporting main legs of a jacked up vessel located over a body of water while said main legs are raised into a stowed position comprising the steps of: extending a semi-submersible controllably buoyaNt means operatively and adjustably connected to said vessel into an underlying body of water; increasing the buoyancy of said means to support said vessel at a predetermined height; raising from said water bottom a set of supporting main legs to a predetermined height above said bottom; lowering said vessel to said water surface; retracting said semi-submersible means to said vessel; and retracting said main legs into a stowed position on said vessel.
Claim 15
Dependent Claim
29 words
The method of claim 9 including the additional step of further increasing the buoyancy of said semi-submersible controllably buoyant means to provide a lifting force on said main legs.
Claim 16
Independent Claim
152 words
A method of reducing destructive forces on a set of supporting main legs of a jacked up vessel located over a body of water, wherein said main legs are embedded in the underwater bottom, while said main legs are raised into a stowed position from said underwater bottom comprising the steps of: extending a semi-submersible controllably buoyant means operatively and adjustably connected to said vessel into an underlying body of water; lowering said vessel to said water surface to provide a buoyant force; increasing the buoyancy of said means to aid in loosening said main legs; loosening said main legs; raising said vessel to a predetermined height above said water surface on said means; raising said main legs to a predetermined height above said underwater bottom; lowering said vessel to the water surface; retracting said semi-submersible means to said vessel; and retracting said main legs into a stowed position on said vessel.
Claim 17
Independent Claim
152 words
A method of reducing destructive forces on a set of supporting main legs of a jacked up vessel located over a body of water, wherein said main legs are embedded in the underwater bottom, while said main legs are raised into a stowed position from said underwater bottom comprising the steps of: extending a semi-submersible controllably buoyant means operatively and adjustably connected to said vessel into an underlying body of water; lowering said vessel to said water surface to provide a buoyant force; increasing the buoyancy of said means to aid in loosening said main legs; loosening said main legs; raising said vessel to a predetermined height above said water surface on said means; raising said main legs to a predetermined height above said underwater bottom; lowering said vessel to the water surface; retracting said semi-submersible means to said vessel; and retracting said main legs into a stowed position on said vessel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |