US3044269A - Mobile sea platform - Google Patents

Description

July 17, 1962 R. G. LE TOURNEAU MOBILE SEA PLATFORM Filed July 22, 1957 5 Sheets-Sheet 1 Fig. 1

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differ/25y United States Patent" 3,044,269 MOBILE SEA PLATFORM Robert G. Le Tourneau, P.O. Box 2307, Lougview, Tex. Filed July 22, 1957, Ser. No. 673,491 5 Claims. (Cl. 6146.5)

My invention relates generally to improvements in mobile sea platforms, and particularly to floatable vessels which are convertible into stabilized structures over bodies of water. My invention is especially applicable to offshore or tidelands oil exploration, drilling, and producing operations.

This application includes disclosure of certain improvements over the mobile sea platforms of my co-pending applications, S.N. 473,885, nowabandoned, filed December 8, 1954, and SN. 625,710, filed December 3, 1956, now U.S. Patent No. 2,924,077.

The general object of my invention is to provide an improved mobile sea platform.

Another object of my invention is to provide a mobile sea platform having improved hull structure.

Another object of my invention is to provide a mobile sea platform incorporating improved spud tower structure.

Another object of my invention is to provide improved rack structure for use in the hull elevating system of a mobile sea platform.

Another object of my invention is to provide improved rack and rack guide structure for use in the hull elevat-' ing system of a mobile sea platform.

- Another object of my invention is to provide improved rack drive arrangements for use in the hull elevating system of a mobile sea platform.

These and other objects are effected by my invention as will be apparent from the following description taken in accordance with the accompanying drawings, forming FIG. 6 is a section view .taken at line 66 of FIG. 2;

; FIG. 7 is a section view taken at line 77 of 'FIG. -2,

with rack guide structures omitted;

FIG. 8 is a schematic side elevational view, partly in phantom, showing a rack drive assembly;

FIG. 9 is a schematic view, partly'in section, taken along line 9-9 of 'FIG. 8, plus a showing of portions of a spud well and hull structure;

on line 10-10 of FIG. 2; and

FIG. 11 is a detail schematic transverse section view of a spud tower column.

Turning now to. the drawings, the basic structure of the platform is shown by FIGS. 1, 2, 6 and 7. The hull 11 has the general shape of an isosceles triangle in plan, with a spud well located at each corner of the triangle, as shown by FIG. 2. The spud well at the triangle vertex will be referred to herein as the forward spud well 13, and the others will be referred to as the rightand left rear spud wells 15, 17, respectively. The principal parts of the hull are sidewalls, bottom, upper or main deck, lower or inner deck, upper deck support beams, upper deck support columns, and lower deck support bulkheads. The hull side wall structure comprises upper and lower box beams 19, 21 held in vertically aligned rigid spaced parallel relation by formed steel plate wall members 23, these steel FIG. 10 is a schematic perspective section view taken 3,044,269 Patented July 17, 1962 ice plate wall members are each formed by a press to assume the shape in transverse section of a portion of a corrugation. Each steel plate wall member is welded at its ends to the respective upper and lower box beam 19, 21, and at its sides to adjacent wall members. Thus, the steel plate wall members form a continuous corrugated web which extends between the upper and lower box beams. .This web together with the upper and lower box beams make up the outer wall of the hull 11. As can be seen from the drawings, the corrugations formed by the steel plate wall members 23 have amplitude such that they extend over most of the width of the box beams 19, 21. As can be seen from FIGS. 1 and 2, the box beams 19, 21 extend all around the outer periphery of the hull 11, and the corrugations likewise, except between the right and left rear spud wells 15, 17 where the corrugations are replaced by a wall section 25 which has the same structure as the decking, to be hereinafter described. The upper and lower box beams 19, 21 in the embodiment herein shown and described have rectangular cross-section, though it is apparent that they could take other cross-section forms, as for example, triangular. The box beams at the spud Wells 13, 15, 17 are twice as wide as elsewhere, and are provided with a vertical partition 27 (see FIG. 10). The hull side wall construction employing upper and lower box beams and the corrugated web as just described, is quite simple, yet is very strong and rigid. The hull bottom is made up of corrugated steel plate members 29 formed like those of the side wall structure. These bottom plates are welded to each other to form the hull bottom, with the valleys of the corrugations running parallel to the center line of the hull 11 which passes midway between the rear spud wells 15, 17. The outer edges of the bottom are welded to the inner side face of the side wall lower box beam 21 (see FIG. 6). The upper or main deck is made up of beams 31 formed from strips of steel plate material. The transverse cross-section of these decking beams may be seen in FIG. 6, and includes a surface portion, a downwardly extending short flange on one side of the surface portion, and a generally block J shaped flange depending from the other side of the surface portion. The decking beams are joined at their longitudinal edges by welding, with the outer surface of the short flange of one beam bearing against the outer surface of the upper portion of the J shaped flange of the adjacent decking beam, with the surface portions of the decking beams lying generally in a common plane. Short stifiener L shaped beams (not shown) extend transversely between adjacent decking beams at spaced intervals and are welded thereto. The decking beams 31 extend in the direction parallel to the hull center line which passes midway between the rear spud wells 15, 17. The decking'is supported by cross beams 33, which extend transversely of the decking beams at spaced intervals and are welded at their ends to the inner face of the side wall upper'box beam 19. The cross beams are supported at spaced intervals by vertical columns 35 which have their footing on the corrugated bottom 29 (see FIGS. 6 and 7). The lower or inner deck of the hull is made up of decking beams 37 which are like the decking beams 31 of the upper deck hereinbefore described. The beams of the lower deck are supported by a plurality of transverse bulkheads 39 which are shaped to conform with the hull bottom corrugations and are welded to the hull bottom members 29. An L shaped stiffener member 41 is fixed by welding to each bulkhead 39, running parallel to bulkheads 39 and trans versely of the decking members 37. A pair of rectangular deck sections 43 extend outwardly from the rear side of center line, to form a slot over which a drilling derrick afiter more fully described.

(not shown) can be erected. The deck extensions 43 are held in place by suitable bracing members 45.

Each of the three spud wells 13, 15, 17, is centered on a line bisecting the angle between respective adjacent hull side walls Each spud well may be considered as having an outer wall portion 47 and an inner wall portion 49. The outer wall portion is generally polygonal in shape, in plan, each side of the polygon being made up ofa length of upper and lower box beam 19, 21 and corrugated web 23 forming a segment of the hull side wall structure as hereinbefore described. The inner wall 49 of each spud 'welliis arcuate in shape, in plan, and is made up of curved steel plate members welded together. blies 51, as well "as rackguide structures 53, to be herein- Each spud well is of course designed toreceive a spud tower 55. The spud towers are of triangular transverse cross-section and each comprises three spud tower columns 57 at the triangle vertices and which are held in rigid spaced parallel relation by tubular latticed trusswork members. A-t spaced intervals along the spud column length there is a tubular truss member 59 disposed between each pair of adjacent spud columns and lying in a horizontal plane. Additional sets'of truss members 61 extend irom near the midpoint of each horizontal truss member 59 at alternate tower levels both upward and downward, to adjacent tower columns. other set of truss members 63 extends vertically from midpoint to midpoint of the horizontal truss members 59. Still another set of truss members 60 extends horizontally at each levelof horizontal truss members and from midpoint to midpoint of same. Each (tower column 57 is made up of a primary member 65, a rack 69, and rack.

support members 67. The primary member 65 is in the form of a heavy steel slab of rectangular cross-section havinga width several times its thickness (see FIG. 11). The primary member may be considered as having a front face 71 and a rear face 73. The rack 69 is disposed in such manner that a plane bisecting the rack and rack face will be perpendicular to the faces of the primary member 65 and will bisect the primary member longitudinally. The rack 69 is held in rigid spaced relation to said primary member by a pair of rack support members 67. The rack support members are heavy steel plate strips welded along one longitudinal edge to the rear face 73 of the primary member 65 and along the other longitudinal edge to a respective side face of the rack 69. In.

transverse cross-section, the rack supportmernbers, 67 form the sides, and. the primary members 65 the base, of an isosceles triangle, with said primary member. extending symmetrically beyond the triangle base on each side thereof. The portions 75 of the primary member which extend beyond the triangle base just mentioned, are utilized as guide surfaces as will be hereinafter more fully explain'ed.

Each spud tower carries a watertight cylindrical pontoon tank 77 at its lower end. Each pontoon tank is provided with sea cocks (not shown) for flooding and draining purposes. Each spud tank is also provided with jetting means (not shown) for the conventional well.

known purpose. Each spud tank is made up of a center column '79, truss work bracing members 81, wall sections 83, a top 85, a bottom 87, and a reinforcing web 89 (see FIG. The center column 79 is a large tubular member centered on the tank longitudinal axis. The bracing members 81 are tubular and may be considered in sets. One set radiates from the center column 79 to the front face 71 of each tower column 57. Another set forms horizontal triangles at a plurality of tower levels, with the tower columns 57 as vertices. wall sections 83, made up of curved steel plate sheets joined by welding and extending between adiacent tower columns 57, with each side edge of each wall section 83 being welded to the front face 71 of a tower column primary member 65.

There are three tank The wall section is in each caseformed suitably to accommodate the tower column guide structure (see FIG. 4). The spud tank top 85 is a convex dish of heavy steel plate material welded to the tank side walls 83. The tank bottom 87 is a concave dish of heavy steel plate material welded to the tank side Walls 83. The bottom reinforcing web 89 is a convex dish of heavy steel plate material with a circular section s removed from its center portion so that the web extends from the inside of the tank bottom upwardly at an angle and joinsthe tank side walls. The web is welded both to 1 the tank bottom 87 and to the tank side walls 83.

Each spud well carries three rack drive as'semand small wall sections 91, 93, 95 respectively. Each of these wall sections has rectangular shape, .The wall sections are held in rigid spaced relation by transverse heavy steel plate partitions 97. The gear case carries three vertically aligned large shaft support openings, and three vertically aligned intermediate shaft support openings.

The large and intermediate shaft support openings for each drive unit are horizontally aligned. The large and intermediate gear case walls carry top, intermediate, and

lower rectangular slots at their left side portions, and the enn're left side of the gear case between the large and intermediate walls is closed by welded steel plate mem-- bers 99. The drive units may be designated as upper, intermediate, and lower. Each drive unit comprises a primary gear box 101 which is a prepackaged self-contained unit, driven by an electric motor 103, and having an output pinion 105. The primary gear box of each drive unit fits into a respective slot of the gear case and is welded thereto. An intermediate gear shaft 107 is journaled in each intermediate shaft support opening, and

r carries a bull gear 109 at one end and an output pinion 111 at the other end. The output pinion 105 of the primary gear box 103 engages the bull gear 109 of the intermediate shaft 107. A large gear shaft 113 is journaled to each large shaft support opening, and carries a bull gear 115 and an output pinion 117. The output pinion 111 of the intermediate shaft 107 engages the bull gear 115 of the large shaft 113, and the output pinion 117 of the large shaft 115 is adapted for engaging the respective rack 69.

There are three gear case assemblies 51 disposed in each spud well. Each gear case is incorporated into the spud well structure in upright position between the upper and lower side wall box beams 19, 21. The height of the gear case is made equal to the distance between the upper and lower box beams, and the top and bottom edges of the gear case are Welded to the respective box beam (see FIG. 10). The gear cases are spaced 120 degrees apart, and so that a respective vertical plane passing through the spud well center is parallel to the gear case side walls and bisects the gear case output pinions. 117, with said plane also bisecting the angle between adjacent hull sides in the case of the outboard drive assembly of each spud well. The manner in which the side walls of a particular gear case are joined to the hull structure is shown by FIG. 9 for the case of an inboard gear box. The right edge of the gear box large wall 91 is welded to a side edge of the spud well arcuate wall section 49. A strip 119 of heavy steel plate extends from the right edge of the gear box small wall at an angle to the right end portion of the gear box large wall 91 and is welded thereto. The left edge of the gear box small wall 95 is joined by a heavy steel plate strip 121 to the end of the corrugated web 23 of the spud well wall. The ends of the corrugated Webs of the spud well wall and the hull side wall are joined by a section of heavy steel plate wall. A section of wall 125 made up of decking, separates the gear box from the hull interior, and is provided with an access opening (not shown).

As hereinbefore mentioned, each spud well is provided with tower column guide structures 53 at each drive assembly location (see FIGS. 4 and There are two vertically aligned tower column guide structures 53 at each drive assembly location. Each guide structure is made up of a pair of parallel spaced guide rails 125 which are generally U shaped in cross section. Each guide rail is held rigid by a support structure composed of heavy steel plate sections. Each guide rail support structure is made up of two trapezoidal side sections 127, a triangular top section 129 and a triangular bottom section. The short parallel side of each trapezoidal section is welded to the respective box beam 19, 21 while the long parallel side is welded to the respective guide rail 125. The trapezoidal sides diverge from the guide rail to the respective box beam. The open ends of the enclosure formed by the trapezoidal side walls, the respective box beam and the respective guide rail are closed by top and bottom triangular sections 129.

The manner of operation and the electrical system of the mobile sea platform herein described is essentially the same as that of the platform disclosed by my copending application S.N. 473,885 aforementioned. The electric drive motors are each equipped with electromagnetic brakes which automatically engage when the motor is de-energized. A heliport 131 is mounted on top of the front spud tower.

While I have shown my invention in only one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

I claim:

1. In combination, a spud well, and a spud in said spud well, said spud comprising a tower structure including a plurality of vertical tower columns forming corners for said structure and a plurality of members forming an open lattice network holding said columns in rigid spaced relationship; each said tower column comprising a vertically disposed flat steel slab of horizontal width several times its thickness, the members of said lattice network being secured to one major vertical face of each said slab inwardly of the vertical edges of said face; a vertical rack bar disposed outwardly of the opposite major face of each slab in a vertical plane bisecting said slab, and vertically disposed horizontally diverging rack support strips connecting opposite side faces of said rack bar to said opposite major face of said slab along vertical lines spaced inwardly from the vertical edges of said face; whereby the vertical longitudinal edges of said slab form extended guide formations free of interference from said lattice network members and said rack supporting strips; and supporting and guiding elements on said spud well in cooperating engagement with said formations.

2. The combination in accordance with claim '1, in which the major plane of each slab is perpendicular to the vertical plane bisecting the corresponding corner angle of said structure.

3. The combination in accordance with claim 1, in which the central vertical plane of each rack bar is coplanar with the vertical plane bisecting the corresponding corner angle of said structure.

4. In combination, a spud well, and a spud in said spud Well, said spud comprising a tower structure including a plurality of vertical tower columns forming corners for said structure and a plurality of members forming an open lattice network holding said columns in rigid spaced relationship; one of said tower columns comprising a vertically disposed flat steel slab of horizontal width several times its thickness, the members of said lattice network being secured to one major vertical face of said slab inwardly of the vertical edges of said face; a vertical rack bar disposed outwardly of the opposite major face of said slab in a vertical plane bisecting said slab, and vertically disposed horizontally diverging rack support strips connecting opposite side faces of said rack bar to said opposite major face of said slab along vertical lines spaced inwardly from the vertical edges of said face; whereby the vertical longitudinal edges of said slabform extended guide formations free of interference from said lattice network members and said rack supporting strips; and supporting and guiding elements on said spud Well in cooperating engagement with saidformations.

5. In combination with a first structural support, a col umn for guided and power-driven lengthwise motion relative to said support, said column comprising: a single elongate flat slab forming the primary member of said column and having a width several times its thickness, a rack bar spaced from one major face of said slab and lying parallel to the length of said slab in the lengthwise bisecting plane thereof, and a pair of elongate flat strips. having one lengthwise edge of each welded to a respective lateral face of said rack bar and diverging angularly therefrom with the other lengthwise edge of each said strip welded to said major face of said slab along respective lines adjacent-and parallel to, but spaced inwardly from the corresponding lengthwise slab edges forming slab-edge guiding formations extending beyond the connections of said strips to said slabs; a second structural support connected to said slab at the other major face of said slab; and means on said first structural support for engaging and receiving said guiding .formations to restrict them to such lengthwise direction of motion.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Popular Science, January 1956, p. 160. Engineering News-Record, Apr. 5, 1956, p. 26.

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