US3429127A - Method and apparatus for establishing a fixed support of a buoyant body in rough water - Google Patents

Method and apparatus for establishing a fixed support of a buoyant body in rough water Download PDF

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US3429127A
US3429127A US526772A US3429127DA US3429127A US 3429127 A US3429127 A US 3429127A US 526772 A US526772 A US 526772A US 3429127D A US3429127D A US 3429127DA US 3429127 A US3429127 A US 3429127A
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pontoon
legs
bed
floats
buoyancy
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US526772A
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Jacobus M Donkers
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Verschure & Co S Scheepswerf E
Verschure & Co's Scheepswerf En Mas Fab Nv
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Verschure & Co S Scheepswerf E
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0203—Containers; Encapsulations, e.g. encapsulation of photodiodes
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • E02B17/021—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto with relative movement between supporting construction and platform
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B15/00—Supports for the drilling machine, e.g. derricks or masts
    • E21B15/003—Supports for the drilling machine, e.g. derricks or masts adapted to be moved on their substructure, e.g. with skidding means; adapted to drill a plurality of wells
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0056—Platforms with supporting legs

Definitions

  • An offshore drilling rig is provided with extensible supporting legs and auxiliary buoyancy devices. The latter raise the rig above its normal buoyancy level so that the legs may be extended and locked whereafter the auxiliary buoyancy is suddenly terminated to set the legs.
  • the invention relates to a method of carrying out operations on the bed of very rough water from a pontoon which is floated to its place of destination and which rests on the bed by means of extensible legs during the operations.
  • the object of the invention is to provide a method of this kind wherein the time during which the pontoon can strike against the bed is reduced to zero.
  • the bottom of the pontoon is first adjusted to a level above the bed such as to correspond to the height of the expected irregularities of the bed plus the wave height, legs freely movable vertically with respect to the pontoon are then brought into contact with the bed, the legs are then secured against displacement with respect to the pontoon and at the same time part of the pontoon buoyancy is eliminated, water ballast is then taken in if necessary to give the required loading of the legs, and after conclusion of the operations the various actions are carried out in the reverse sequence.
  • the reincorporation of the eliminated buoyance take place at the moment the pontoon is on a Wave crest.
  • the loading occurring as a result of elimination of part of the buoyancy is then intensified by the Water level which is falling with respect to the pontoon.
  • On re-incorporation of the buoyancy there is no reversal of the direction of the forces when the water next falls. This gives maximum stability for the floating pontoon.
  • that part of the pontoon which is required to provide the eliminated buoyancy during operations can be kept above the water level. This part of the pontoon cannot then exert horizontal forces on the pontoon as a result of the Water movement.
  • the pontoon before operations are started the pontoon can be lowered with respect to the legs to an extent such that that portion of the pontoon which is required to provide the remaining buoyancy is as far as possible outside the influence of the wave motion.
  • the loading of hte pontoon in the horizontal direction during 3,429,127 Patented Feb. 25, 1969 the performance of the Operations is also reduced as a result.
  • the invention also relates to a pontoon for performing one or more of the above-described methods, such a pontoon having extensible legs movable freely with respect to the pontoon and adapted to be secured against displacement with respect to the pontoon.
  • a number of the floats of the pontoon are vertically movable with respect to the pontoon and can be secured against displacement in any required position with respect to the pontoon.
  • a considerable loading on the pontoon legs can be obtained in an infinitely short time by suddenly eliminating the security of these movable floats against displacement.
  • the movable floats are each secured to the free end of an arm pivotally connected to the outside of the pontoon, said arm being adapted to swing in a vertical plane and lockable at a given angle with respect to the pontoon by means of cables secured to said arm any by means of a Winch disposed on the pontoon.
  • a construction of this kind for the pontoon gives maximum stability while the movable floats are in operation, while when they are in-operative they can be brought as close to the pontoon as possible so as to provide the minimum obstruction.
  • FIG. 1 is an end view of a pontoon according to the invention.
  • FIG. 2 is a top plan view of a pontoon shown in FIG. 1.
  • the pontoon consists of a rectangular box-shaped frame-work 1 having a free opening 2 which can be covered by grids to form a work floor.
  • One or more travelling bridge structures 3 are provided on the frame work and each bears a drilling derrick 4 adapted to travel over the bridge structure.
  • posts 5 By means of posts 5 the framework '1 rests on longitudinally extending cylindrical floats 6.
  • These cylinders can also accommodate water ballast and they also contain chambers for the storage of oil and drinking water, pump chambers also being provided in said floats.
  • Extending legs 7 with the associated actuating mechanisms are provided in the posts 5 which are disposed at the corners of the framework.
  • the legs 7 are actuated by hydraulic cylinders. They can be locked in any required position with respect to the posts 5 and can also be connected to a compensation system (not shown) to enable the legs 7 to rest on the sea bed, while the framework 1 can move freely up and down along the legs 7 via the posts 5 under the influence of the rise and fall of the' Water.
  • a winch 11 is provided on the pontoon for each float 10 and comprises two drums 12 and 13, one of which has a cable 15 running over it to the end of the arm 9 via pulley 14. From the other drum a cable 18 extends to the free end of the arm 9 via a pulley 16 and a pulley 17, the latter being secured to a float 6.
  • the float 10 can be hoisted to position 10 by means of cable 15.
  • the buoyancy provided by the float 10 can be transmitted to the pontoon by means of the cable 18, which may comprise a plurality of parts. Since the floats 10 are situated at a relatively considerable distance outside the boxshaped framework 1, the floats 10 contribute very considerably to the stability of the floating pontoon.
  • the winch 11 also comprises a drum 19 on which a cable 20 can be wound, by means of lwhich the pontoon can be anchored at the four corners.
  • the procedure is as follows.
  • the pontoon is first anchored at the required place by means of cables 20 and then the pontoon draught is so adjusted by pumping water ballast into the floats 6 that the bottom of the latter is at a distance from the bed 21 equal to the expected irregularities of the bed 21 plus the wave height in order to assure that the floats 6 do not strike the bed when the pontoon is in the trough between waves, the cables 15 and 18 being used to adjust the floats 10 so that they are substantially half submerged.
  • the legs 7 are then dropped until they rest on the bed 21 while still being freely movable with respect to the posts 5. At this point, the floats 10 are substantially half submerged while the buoyancy of the entire structure is such as to place the floats 6 in such a position that they are in proximity to the bed 21 but cannot strike it when the trough between waves is encountered.
  • the legs 7 are secured against displacement with respect to the posts 5 and at the same time the cable 18 is released. A great part of the weight of the pontoon thus comes to rest on the legs 7 in one operation. The legs cannot therefore have any pushing action on the bed.
  • the floats are then raised to position 10' by means of the cables 15. Water ballast is also admitted to the floats 6 to increase the loading of the legs 7 whenever necessary.
  • the pontoon can also be lowered along the legs 7 so that the floats 6 are removed from the influence of the wave motion.
  • the original distance between the bottom of the floats 6 and the bed 21 is restored.
  • the water ballast is then reduced until the pontoon is just not floating on a wave crest.
  • the floats 10 are then lowered and cable 18 is payed out until the floats: 10 can follow the wave motion.
  • the legs 7 are freed and the floats 10 are adjusted by means of the cables and 18 so that they are half submerged. The legs 7 can then be drawn up and the required pontoon draught can be obtained by pumping out water ballast.
  • a method of carrying out operations on the bed of very rough water from a pontoon which is floated to its place of destination and which rests on the bed by means of extensible legs during the operations comprises adjusting the buoyancy of the pontoon so that the bottom of the pontoon is first adjusted to a level above the bed such as to correspond to the height of the expected irregularities of the bed plus the Wave height, contacting legs with the bed while maintaining such legs freely movable vertically with respect to the pontoon, and then simultaneously securing said legs against displacement with respect to the pontoon and at the same time eliminating part of the pontoon buoyancy.
  • a pontoon assembly adapted to be floated to a desired location on a body of Water and then supported on the bed of the body of water comprising, in combination,
  • buoyant means pivotally attached to said pontoon
  • legs for supporting said pontoon on the bed, said legs including extensible portions so that the legs are, in eflect, rigid depending extensions from said pontoon,
  • a pontoon according to claim 2 wherein said buoyant means are in the form of floats, each secured to the free end of an arm pivotally connected to the outside of the pontoon, each arm being adapted to swing in a vertical plane and lockable at a given angle with respect to the pontoon by means of cables secured to said arm and by means of a winch disposed on the pontoon.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Mining & Mineral Resources (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Power Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Bridges Or Land Bridges (AREA)
  • Revetment (AREA)
  • Earth Drilling (AREA)
  • Jib Cranes (AREA)

Description

3,429,127 ESTABLISHING A FIXED su ODY IN ROUGH WATER PPORT Feb. 25, 1969 J. M. DONKERS METHOD AND APPARATUS FOR OF A BUOYANT B Filed Feb. 11, 1966 Fl 6. I
INVENTOR JACOBUS M. DONKERS ATTORNEYS.
6501996 US. Cl. 61-46.5 Int. Cl. E02!) 17/02 3 Claims ABSTRACT OF THE DISCLOSURE An offshore drilling rig is provided with extensible supporting legs and auxiliary buoyancy devices. The latter raise the rig above its normal buoyancy level so that the legs may be extended and locked whereafter the auxiliary buoyancy is suddenly terminated to set the legs.
The invention relates to a method of carrying out operations on the bed of very rough water from a pontoon which is floated to its place of destination and which rests on the bed by means of extensible legs during the operations. The object of the invention is to provide a method of this kind wherein the time during which the pontoon can strike against the bed is reduced to zero. To this end, according to the invention, at the destination the bottom of the pontoon is first adjusted to a level above the bed such as to correspond to the height of the expected irregularities of the bed plus the wave height, legs freely movable vertically with respect to the pontoon are then brought into contact with the bed, the legs are then secured against displacement with respect to the pontoon and at the same time part of the pontoon buoyancy is eliminated, water ballast is then taken in if necessary to give the required loading of the legs, and after conclusion of the operations the various actions are carried out in the reverse sequence. By means of such a method, at the same time as the connection to the pontoon is effected the legs are subjected to such heavy loading in an infinitely short time that they can no longer come free of the bed and hence a collision with the bed is impossible. The dan gerous transition time between the floating of the pontoon and the time when the same rests on the bed via the legs with an adequate loading is thus avoided.
According to the invention, before operations begin the simultaneous securing of the legs and elimination of part of the buoyancy and after completion of the activities the reincorporation of the eliminated buoyance take place at the moment the pontoon is on a Wave crest. The loading occurring as a result of elimination of part of the buoyancy is then intensified by the Water level which is falling with respect to the pontoon. On re-incorporation of the buoyancy, there is no reversal of the direction of the forces when the water next falls. This gives maximum stability for the floating pontoon.
According to the invention, that part of the pontoon which is required to provide the eliminated buoyancy during operations can be kept above the water level. This part of the pontoon cannot then exert horizontal forces on the pontoon as a result of the Water movement.
According to the invention, before operations are started the pontoon can be lowered with respect to the legs to an extent such that that portion of the pontoon which is required to provide the remaining buoyancy is as far as possible outside the influence of the wave motion. The loading of hte pontoon in the horizontal direction during 3,429,127 Patented Feb. 25, 1969 the performance of the Operations is also reduced as a result.
The invention also relates to a pontoon for performing one or more of the above-described methods, such a pontoon having extensible legs movable freely with respect to the pontoon and adapted to be secured against displacement with respect to the pontoon.
To this end, according to the invention, a number of the floats of the pontoon are vertically movable with respect to the pontoon and can be secured against displacement in any required position with respect to the pontoon. A considerable loading on the pontoon legs can be obtained in an infinitely short time by suddenly eliminating the security of these movable floats against displacement.
In one advantageous embodiment of the pontoon according to the invention, the movable floats are each secured to the free end of an arm pivotally connected to the outside of the pontoon, said arm being adapted to swing in a vertical plane and lockable at a given angle with respect to the pontoon by means of cables secured to said arm any by means of a Winch disposed on the pontoon. A construction of this kind for the pontoon gives maximum stability while the movable floats are in operation, while when they are in-operative they can be brought as close to the pontoon as possible so as to provide the minimum obstruction.
The invention will be explained in detail in the following description of one exemplified embodiment of a pontoon according to the invention with reference to the accompanying drawing, wherein:
FIG. 1 is an end view of a pontoon according to the invention.
FIG. 2 is a top plan view of a pontoon shown in FIG. 1.
The pontoon consists of a rectangular box-shaped frame-work 1 having a free opening 2 which can be covered by grids to form a work floor. One or more travelling bridge structures 3 are provided on the frame work and each bears a drilling derrick 4 adapted to travel over the bridge structure. By means of posts 5 the framework '1 rests on longitudinally extending cylindrical floats 6.
These cylinders can also accommodate water ballast and they also contain chambers for the storage of oil and drinking water, pump chambers also being provided in said floats.
Extending legs 7 with the associated actuating mechanisms are provided in the posts 5 which are disposed at the corners of the framework. The legs 7 are actuated by hydraulic cylinders. They can be locked in any required position with respect to the posts 5 and can also be connected to a compensation system (not shown) to enable the legs 7 to rest on the sea bed, while the framework 1 can move freely up and down along the legs 7 via the posts 5 under the influence of the rise and fall of the' Water.
Laterally of the pontoon, arms 9 in the form of triangular frameworks are secured by hinges at 8 to pairs of the posts 5 and they carried vertically movable floats 10. A winch 11 is provided on the pontoon for each float 10 and comprises two drums 12 and 13, one of which has a cable 15 running over it to the end of the arm 9 via pulley 14. From the other drum a cable 18 extends to the free end of the arm 9 via a pulley 16 and a pulley 17, the latter being secured to a float 6. The float 10 can be hoisted to position 10 by means of cable 15. The buoyancy provided by the float 10 can be transmitted to the pontoon by means of the cable 18, which may comprise a plurality of parts. Since the floats 10 are situated at a relatively considerable distance outside the boxshaped framework 1, the floats 10 contribute very considerably to the stability of the floating pontoon.
The winch 11 also comprises a drum 19 on which a cable 20 can be wound, by means of lwhich the pontoon can be anchored at the four corners.
When it is required to place the pontoon on the bed 21 the procedure is as follows. The pontoon is first anchored at the required place by means of cables 20 and then the pontoon draught is so adjusted by pumping water ballast into the floats 6 that the bottom of the latter is at a distance from the bed 21 equal to the expected irregularities of the bed 21 plus the wave height in order to assure that the floats 6 do not strike the bed when the pontoon is in the trough between waves, the cables 15 and 18 being used to adjust the floats 10 so that they are substantially half submerged. The legs 7 are then dropped until they rest on the bed 21 while still being freely movable with respect to the posts 5. At this point, the floats 10 are substantially half submerged while the buoyancy of the entire structure is such as to place the floats 6 in such a position that they are in proximity to the bed 21 but cannot strike it when the trough between waves is encountered.
When the pontoon is at the crest of a wave, the legs 7 are secured against displacement with respect to the posts 5 and at the same time the cable 18 is released. A great part of the weight of the pontoon thus comes to rest on the legs 7 in one operation. The legs cannot therefore have any pushing action on the bed. The floats are then raised to position 10' by means of the cables 15. Water ballast is also admitted to the floats 6 to increase the loading of the legs 7 whenever necessary. The pontoon can also be lowered along the legs 7 so that the floats 6 are removed from the influence of the wave motion.
When it is required to release the pontoon from the bed after operation, the original distance between the bottom of the floats 6 and the bed 21 is restored. The water ballast is then reduced until the pontoon is just not floating on a wave crest. The floats 10 are then lowered and cable 18 is payed out until the floats: 10 can follow the wave motion. After the winch drums have been locked the legs 7 are freed and the floats 10 are adjusted by means of the cables and 18 so that they are half submerged. The legs 7 can then be drawn up and the required pontoon draught can be obtained by pumping out water ballast.
What I claim is:
1. A method of carrying out operations on the bed of very rough water from a pontoon which is floated to its place of destination and which rests on the bed by means of extensible legs during the operations, which method comprises adjusting the buoyancy of the pontoon so that the bottom of the pontoon is first adjusted to a level above the bed such as to correspond to the height of the expected irregularities of the bed plus the Wave height, contacting legs with the bed while maintaining such legs freely movable vertically with respect to the pontoon, and then simultaneously securing said legs against displacement with respect to the pontoon and at the same time eliminating part of the pontoon buoyancy.
2. A pontoon assembly adapted to be floated to a desired location on a body of Water and then supported on the bed of the body of water comprising, in combination,
a pontoon,
buoyant means pivotally attached to said pontoon,
motion transmitting means for forcing said buoyant means downwardly in the body of water to increase the buoyancy of the assembly,
a plurality of legs for supporting said pontoon on the bed, said legs including extensible portions so that the legs are, in eflect, rigid depending extensions from said pontoon,
means for releasing said motion transmitting means suddenly to decrease the buoyancy of the assembly, and
means for locking said extensible portions of the legs in engagement with the bed.
3. A pontoon according to claim 2 wherein said buoyant means are in the form of floats, each secured to the free end of an arm pivotally connected to the outside of the pontoon, each arm being adapted to swing in a vertical plane and lockable at a given angle with respect to the pontoon by means of cables secured to said arm and by means of a winch disposed on the pontoon.
References Cited UNITED STATES PATENTS 2,525,955 10/1950 Scott 6l--46.5 2,846,851 8/1958 Pelhan'i 6l46.5 2,895,300 7/1959 Hayward 6l46.5 2,938,352 5/1960 Knapp et a1. 6l-46.5 3,118,283 1/1964 True et al 6146.5 3,289,419 12/1966 McGowen 6146.S
JACOB SHAPIRO, Primary Examiner.
US526772A 1965-02-17 1966-02-11 Method and apparatus for establishing a fixed support of a buoyant body in rough water Expired - Lifetime US3429127A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041711A (en) * 1973-04-23 1977-08-16 Marine Engineering Co., C.A. Method and apparatus for quickly erecting off-shore platforms
US4969776A (en) * 1986-02-24 1990-11-13 British Gas Plc Offshore platforms
NL1026301C2 (en) * 2004-06-01 2005-12-05 Heerema Marine Contractors Nl Method for raising a structure at least partially submerged in water.
CN102268967A (en) * 2010-06-04 2011-12-07 中国海洋石油总公司 Anti-collision protection device for drilling machine derrick
WO2019043400A1 (en) * 2017-09-01 2019-03-07 Sllp 134 Limited System for providing stability to a floating offshore structure
WO2019145681A1 (en) * 2018-01-24 2019-08-01 Shane Carr Ltd Floating deck assembly
GB2583597A (en) * 2018-01-24 2020-11-04 Tugdock Ltd Floating deck assembly

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525955A (en) * 1947-03-21 1950-10-17 Harold W Scott Apparatus for submarine drilling
US2846851A (en) * 1955-01-21 1958-08-12 Pelham George Fred Marine apparatus
US2895300A (en) * 1953-07-22 1959-07-21 John T Hayward Method and apparatus for stabilizing submersible vessels
US2938352A (en) * 1954-12-13 1960-05-31 Jersey Prod Res Co Deep water recoverable drilling platform
US3118283A (en) * 1964-01-21 Xkilling barge
US3289419A (en) * 1964-02-03 1966-12-06 Camco Inc Sea raft

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3118283A (en) * 1964-01-21 Xkilling barge
US2525955A (en) * 1947-03-21 1950-10-17 Harold W Scott Apparatus for submarine drilling
US2895300A (en) * 1953-07-22 1959-07-21 John T Hayward Method and apparatus for stabilizing submersible vessels
US2938352A (en) * 1954-12-13 1960-05-31 Jersey Prod Res Co Deep water recoverable drilling platform
US2846851A (en) * 1955-01-21 1958-08-12 Pelham George Fred Marine apparatus
US3289419A (en) * 1964-02-03 1966-12-06 Camco Inc Sea raft

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041711A (en) * 1973-04-23 1977-08-16 Marine Engineering Co., C.A. Method and apparatus for quickly erecting off-shore platforms
US4969776A (en) * 1986-02-24 1990-11-13 British Gas Plc Offshore platforms
NL1026301C2 (en) * 2004-06-01 2005-12-05 Heerema Marine Contractors Nl Method for raising a structure at least partially submerged in water.
CN102268967A (en) * 2010-06-04 2011-12-07 中国海洋石油总公司 Anti-collision protection device for drilling machine derrick
WO2019043400A1 (en) * 2017-09-01 2019-03-07 Sllp 134 Limited System for providing stability to a floating offshore structure
WO2019145681A1 (en) * 2018-01-24 2019-08-01 Shane Carr Ltd Floating deck assembly
GB2583597A (en) * 2018-01-24 2020-11-04 Tugdock Ltd Floating deck assembly
GB2583597B (en) * 2018-01-24 2021-06-16 Tugdock Ltd Floating dry dock assembly

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NL6501996A (en) 1966-08-18
DE1634651A1 (en) 1970-09-17
DE1634651B2 (en) 1976-11-04
GB1135273A (en) 1968-12-04

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