Self-elevating offshore platform with folding legs

Claim 2

An offshore work platform comprising: a. a floating hull on which is carried a working deck and associated apparatus; b. a plurality of legs attached to said hull and vertically movable from a raised position, supported by said hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs; c. means for moving said legs from said raised position to said lowered position and for elevating said hull above said body of water; and d. each of said legs comprising aN upper section and a lower section, said lower section being pivotally connected to said upper section for arcurate movement from a position depending downwardly from said hull to a horizontal position underneath said hull for carriage during water travel, each of said legs being provided with positioning means for moving said lower leg section between said downwardly depending position and said horizontal position underneath said hull.

Claim 3

An offshore work platform as set forth in claim 1 in which said positioning means comprises ballast means including tanks carried by said lower leg section.

Claim 4

An offshore work platform as set forth in claim 1 comprising fastening means on said upper and lower leg sections for rigidly fastening said leg sections together when said lower section is in said downwardly depending position.

Claim 5

An offshore work platform comprising: a. a floating hull on which is carried a working deck and associated apparatus; b. a plurality of legs attached to said hull and vertically movable from a raised position, supported by said hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs, each of said legs comprising an upper section and a lower section, said lower section being pivotally connected to said upper section for arcuate movement from a position depending downwardly from said hull to a horizontal position underneath said hull for carriage during water travel, said lower leg section being adapted for limited longitudinal movement relative to said upper section, in said downwardly depending position, between a non-fastened position and a fastened position; c. fastening means on said upper and lower leg sections for rigidly fastening said leg sections together when said lower section is in said downwardly depending fastened position; and d. means for moving said legs from said raised position to said lowered position and for elevating said hull above said body of water.

Claim 6

An offshore work platform comprising: a. a floating hull on which is carried a working deck and associated apparatus; b. a plurality of legs attached to said hull and vertically movable from a raised position, supported by said hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs, each of said legs comprising an upper section and a lower section, said lower section being pivotally connected to said upper section for arcuate movement from a position depending downwardly from said hull to a horizontal position underneath said hull for carriage during water travel, said lower leg section being adapted for limited longitudinal movement relative to said upper section, in said downwardly depending position, between a non-fastened position and a fastened position; c. fastening means on said upper and lower leg sections for rigidly fastening said leg sections together when said lower section is in said downwardly depending fastened position; and d. means for moving said legs from said raised position to said lowered position and for elevating said hull above said body of water.

Claim 7

An offshore work platform as set forth in claim 4 comprising elevator means connected to said upper and lower leg section for moving said lower section from said non-fastened position to said fastened position.

Claim 8

An offshore work platform as set forth in claim 3 comprising elevator means connected to said upper and lower leg section for forcibly aligning said sections to permit said fastening by said fastening means.

Claim 9

An offshore work platform as set forth in claim 6 in which said elevator means comprises a stationary portion affixed to said upper leg section operatively engaging a longitudinally movable portion affixed to said lower leg section.

Claim 10

An offshore work platform as set forth in claim 7 in which said elevator means comprises rack and pinion apparatus.

Claim 11

An offshore work platform as set forth in claim 7 in which said elevator means comprises a power screw device.

Claim 12

An offshore drilling unit of the self-elevating platform type having a floating hull and a plurality of legs movable from a raised position, in which said legs are supported by said floating hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs, characterized in that said legs are of articulated construction permitting a first portion of each leg, when in said raised position, to swing from longitudinal alignment with a second portion of the leg to a horizontal position underneath said hull for carriage during water travel, said first portion of said leg being attached to said second portion in rigid longitudinal alignment therewith by pivot means and disengageable fastening means, disengagement of said fastening means permitting said lower portion to swing about said pivot means, when in said raised position, between said longitudinal alignment and said horizontal position underneath said hull; positioning means being provided with each of said legs for moving said first leg portion between said longitudinal alignment and said horizontal pOsition underneath said hull.

Claim 13

An offshore drilling unit of the self-elevating platform type having a floating hull and a plurality of legs movable from a raised position, in which said legs are supported by said floating hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs, characterized in that said legs are of articulated construction permitting a first portion of each leg, when in said raised position, to swing from longitudinal alignment with a second portion of the leg to a horizontal position underneath said hull for carriage during water travel, said first portion of said leg being attached to said second portion in rigid longitudinal alignment therewith by pivot means and disengageable fastening means, disengagement of said fastening means permitting said lower portion to swing about said pivot means, when in said raised position, between said longitudinal alignment and said horizontal position underneath said hull; positioning means being provided with each of said legs for moving said first leg portion between said longitudinal alignment and said horizontal pOsition underneath said hull.

Claim 14

An offshore drilling unit as set forth in claim 10 in which said positioning means comprises ballast means including tanks carried by said first leg portion.

Claim 15

An offshore drilling unit as set forth in claim 11 comprising retainer means on said first leg portion and said hull engageable to retain said first leg in said horizontal position.

Claim 16

An offshore drilling unit of the self-elevating platform type having a floating hull and a plurality of legs movable from a raised position, in which said legs are supported by said floating hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs; characterized in that said legs comprise articulated first and second portions connected by pivot means allowing said first portion, when in said raised position, to swing from longitudinal alignment with said second portion to a horizontal position underneath said hull for carriage during water travel, said first and second portions of said leg being attached in rigid longitudinal alignment by disengageable fastening means, disengagement of said fastening means permitting said first portion to swing about said pivot means, when in said raised position, between said longitudinal alignment and said horizontal position underneath said hull, elevator means being connected to said first and second leg portions for moving said fastening means into engagement.

Claim 17

An offshore drilling unit of the self-elevating platform type having a floating hull and a plurality of legs movable from a raised position, in which said legs are supported by said floating hull, to a lowered position engaging the floor of a body of water, in which said hull is supported on said legs; characterized in that said legs comprise articulated first and second portions connected by pivot means allowing said first portion, when in said raised position, to swing from longitudinal alignment with said second portion to a horizontal position underneath said hull for carriage during water travel, said first and second portions of said leg being attached in rigid longitudinal alignment by disengageable fastening means, disengagement of said fastening means permitting said first portion to swing about said pivot means, when in said raised position, between said longitudinal alignment and said horizontal position underneath said hull, elevator means being connected to said first and second leg portions for moving said fastening means into engagement.

Claim 18

An offshore drilling unit as set forth in claim 13 in which said first leg portion is adapted for limited longitudinal movement by said elevator means when in said longitudinal alignment with said second leg portion.

Claim 19

An offshore drilling unit as set forth in claim 14 in which said fastening means comprises pin means on one of said leg portions and a socket means on the other, said pin means being telescopically received by said socket means on said engagement of said fastening means.

Claim 20

An offshore drilling unit as set forth in claim 14 in which said pivot means comprises link means pivotally connected at one end to said elevator means and at the opposite end to one of said leg portions.

Claim 21

An offshore drilling unit as set forth in claim 16 in which said leg portions comprise longitudinal chord members, said fastening means comprising pins at the ends of the chord members of one of said leg portions and sockets at the ends of the chord members of the other of said leg members, said limited longitudinal movement of said first leg portion by said elevator means effecting the engagement of said pins and sockets for said rigid longitudinal alignment.