US2539695A

US2539695A - Portable marine structure

Info

Publication number: US2539695A
Application number: US776633A
Authority: US
Inventors: Moon James
Original assignee: Signal Oil and Gas Co
Current assignee: Signal Oil and Gas Co
Priority date: 1947-09-29
Filing date: 1947-09-29
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

Jan. 30, 1951 J. MooN 2,539,695

PORTABLE MARINE STRUCTURE Filed Sept. 29. 1947 9 Sheets-Sheet l 24M4 zo 13 l f luim WATER Jan. 30, 1951 J. MOON PORTABLE MARINE STRUCTURE 9 Sheets-Sheet 2 Filed Sept. 29, 1947 WIT!! ATTORNEY.

Jan. 30, 1951 J. MOON PORTABLE MARINE STRUCTURE Filed Sept. 29, 1947 9 Sheets-Sheet 5 Il im h' a I', m C@ 3 1.5 ,07 f* 3 lIL-\\\ I I I3 V f; ir i 1 I 15 :00 15 l 3 l ns1- "8 1 8 -f* I wm'sz i LEVEL E I l 57 1 1791 /76 JNVENTOR. 54 Hn- 71 Jamas M00 96 T T* '7o 57 20 ATTORNEY.

Jan. so, 1951 J. MOON 2,539,695

RTABLE MARINE STRUCTURE WATER Jan. 30, 1951 J. MOON 2,539,695

PORTABLE MARINE STRUCTURE Filed Sept. 29, 1947 9 Sheets-Sheet 5 "HIL ,'97

IN VEN TOR.

ATTO/av Jan. 30, 1951 J. MOON 2,539,695

PORTABLE MARINE STRUCTURE Filed Sept. 29, 1947 9 Sheets-Sheet 6 IN VEN TOR.

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Jan. 30, 1951 J. MOON PORTABLE MARINE STRUCTURE 9 Sheets-Sheet 7 Filed Sept. 29, 1947 JNVENToR. llames Moo Jan, 30, 1951 J. MOON 2,539,695

PORTABLE MARINE STRUCTURE Filed Sept. 29, 1.947 9 SheebS-Sheer. 8

FQJZ

INVENTOR. l( 6217165 N gli f1 BY ATTORNEY.

Jan. s, 1951 J, MOON 2,539,695

'PORTABLE MARINE STRUCTURE Filed sept. 29, 71947 9 Sheets-sheet 9 1N V EN TOR. jfoz Patented Jan. 30, 1951 l 2,539,695 PORTABLE MARINE STRUCTURE James Moon, Altadena,I Calif., assignor to Signal Oil and Gas Company, Los Angeles, Calif., a corporation of Delaware Application september 29, 1947, serial No. 776.633

24 claims. 1

The problem of erecting a safe platform in deep Water disconnected from the land has involved the attention of marine and civil engineers because of its utility for many purposes. The most important practical utility to date is, however, in drilling for oil in ocean bottoms. The earliest solution of this problem was the steel island disclosed in the Roberts Patent No. 1,867,031 which was erected olf the coast of California. This was a steel structure formed of steel piles driven into the submarine bottom and crossbraced under Water by tension members tied by clamps to the main columns. This structure, although it gave many years of useful service, finally collapsed into the ocean. The structure was not transportable and disassemblable and had to be erected at the site from its individual members.

Recently a variation of the Roberts structure has been constructed in the Lake Maracaibo region, employing concrete piles or concrete iilled steel tubular piles.

Other solutions of the problem involve the use of submersible barges such as are shown in the Giliasso Patent No. 1,681,533. Many such barges have been employed, but they are of a nature suitable for shallow water only and have been used in the Gulf of Mexico, in the shallow waters off the coast of Texas and Louisiana. I These represent the main type of structure unconnected to the land which have been employed for drilling operations. Others have been suggested but not employed.

I have devised a structure capable of use in deep water, in rivers, lakes, bays, seas, or other bottoms, herein generally referred to as marine bottoms, which is transportable in sections to the site where the structure is to be erected, assemblable at the site, and, if thereafter desired, disassemblable and transportable in sections.

My invention relates to an assemblable platform or island capable of being erected both in shallow and in deep water and to a depth of 100 feet or more and which may be either disassembled into its original sections or permanently fixed in the bottom'underlying the Waters in which it is erected.

(Cl. (i1-46) My structure is composed of prefabricated cell sections which may be launched individually or in groups from the shore and floated and towed to position and erected seriatum and joined t0- gether on the marine bottom to give the type of structure desired.

The connections between the several sections foundation for any desired superstructure, such as the equipment necessary to marine oil well drilling operations, and may also be, and preferably is, disassemblable when the drilling operation is of a prospecting nature.

I construct my structure of cell units, each unit having a flotation tank which can be flooded to cause the cell to sink onto the ocean bottom in an erect position. The tank can be filled with a weighting fluid, such as water or heavy mud, which can be withdrawn when the cell is to be reoated, or may be illled with cement when a permanent foundation is to be provided.

I preferably employ two such tanks, one at each end, and ilood one of said tanks under controlled conditions to cause the unit to pivot into an erect position. I preferably employ hollow tubular members for the column supports of my cell and obtain as a result an advantage in that these columns can form the conduits for introduction and discharge of the weighting fluid or form the conduits for introduction of cement. The columns can also form conduits for introduction of water for jetting action by a jet positioned on one of said columns, to clear the foundation to insure a stable foundation for the cell. One or more of said columns can also be employed as a means for levelling the cell, as will be more fully set forth below.

In order to facilitate the assembly of the cells into an island or wharf structure, I may and pref'- erably do provide alignment joints on the cells whereby the cells may be accurately assembled into a multiple cell structure.

For purposes of prospect drilling or oil well production, I assemble these units into a drilling visland and preferably one in which wing piers and a slip are provided by adding onto the drilling platform twospaced wing piers formed of the assembly cell sections.

In a preferred modification of such structure. I also provide a drilling barge which may be moved into position in said slip. This drilling barge may carry the power plant for the drilling or servicing operation and a retractible and collapsible derrick for drilling or servicing of the well.

I also desirably provide means for elevating the barge from the water and position the barge on the wing piers in operative relation to the drill pipe for drilling or to the well for servicing. When so positioned the derrick may be erected in operating position by means mounted on the barge. It may then be lowered and at any stage and their form of structure will give a stable in the procedure, as when storm connections 3 makeitdcsirablcsotodo. Thcdrillingorccrw.

icing operations may be suspended, the drrlck lowered, and. ir desired.' the barge lowered into the water for movement-to a safe harbor.

This invention will be further described by reierence to the accompanying drawings. in which:

Fig. 1 is a vertical view oi a cell employed in erecting the structure ot my invention;

Fig. 2 is a detail oione ot the columns ofmy invention with parts in section and parts broken Sway:

Fig. 3 is a side view of Fig. 1;

Fig.4isabottomvieworFig.lwithparts broken away;

Fig. 4a is a sectional view of another lof the columns of Fig. l;

Fig. 4b is a section taken on line 4b-4b of Fis- 4G;

Fig. 4c is a detail section oi.' an attachment to Fig. 4a;

Fig. 4d is a sectional detail of the end of another of the columns of Fig. l:

Fig. 5 is a side view of the structure of my invention;

Fig. is an end view o! Fig. 5 showing the derrick retracted on the barge and the barge broken away;

Fig. 7 is a plan view of Fig. 5, showing the derrick retracted and drilling equipment removed;

Fig. 8 is a section taken on line 8-8 of Fig. 7 with parts broken away, showing the rotary table and the casing attachments in position;

Fig. 9 is a section taken on line 9-9 of F18. 8;

Fig. 10 is a fragmentary section taken on line I6--I0 of Fig. 9;

Fig. 11 is a section taken on line II-II of Fig. 5;

Fig. 12 is a section taken on line I2--I2 of Fis. 5;

Fig. 13 is an exploded fragmentary section taken on line I3-I3 of Fig. 6;

Fig. 13a. is a side View taken on line i3d-Ita of Fig. 13;

Fig. 14 is a schematic plan view of the barge with the derrick and derrick elevating mechanism removed;

Fig. 15 is a section taken on line IB-IS of Fig. 14, showing the derrick mounted in its retracted position;

Fig. 16 is a fragmentary section taken on line I6-I6 of Fig. 15; and

Figs. 17 to 24, inclusive, are schematic views showing the various stages in the erection of the structure of my invention illustrating the method of erection. e

The portable marine structure of my invention is composed of a drilling platform I, a slip 2 formed of two wingpiers 3 (see Figs. 5, 6, and 7) The platform is of cellular construction composed of a center cell 4, side cells 5 and 5', and

end cells

6, 6', and 6". Each of the wing piers is composed of a plurality of cells 'I composed of four

tubular columns

8, 8. 9 and I0 (see particularly Figs. 4 and 13a) positioned at the corners of the cells and connected by suitable bracing between adjacent columns. In like manner, the cells of the drilling platform are formed of cells similarly constructed but of greater width, length, and height, and with other variations more fully set forth below.

Mounted at the top of the cell is a top tank II and mounted at the bottom of each cell is a bottom tank I2 to be further described. The top and bottom tanks are similarly constructed and formed of side walls I3, top I4, and bottom I5 tank to make an air-tight and water-tight joint n by welding, brazing, or other methods of attachment.

The tanks are oblong in cross section, and upon one oblong side of the tank is positioned a plate Il carrying a central boss I8 (see Figs. 1, l2. 12a, and 13). 0n the opposite side of the tank is positioned a plate I1' and a detent I9 axially positioned with the boss I8 (see Figs. l, l2, and 13). Tanks Ii and I2 are similarly provided with such bosses and detents. Fianges 20 are attached to the corners oi the top and bottom tanks.

A letting nozzle 2| carrying side jet orifices 22 and endl Jet orifices 23 are positioned in the bottom of the hollow tubular column 8. A plug 24 is screwed into the top of the column 8 (see Figs. 4a, 4b, and 4c). This plug may be withdrawn by unscrewing and. a tubular iitting 25 may take the place of the plug 24. A pipe 26 may be connected to this tting by means of a union 2l, as

will be further described.

A cylindrical barrel 28 is xed in the column 8' near the bottom of the tubular column (see Fig. 4d) and a cylinder head 30 carrying an orlfice 32 is connected to the barrel 28. Slidably positioned in the barrel is a piston 29 suitably provided with wall packing 3|. Piston rod 33 passes through a packing gland 34 and is connected to a levelling foot 3l by a ball and socket joint composed of socket 35 and a ball adjustably mounted in the socket by a nut and stud 38 mounted to give suicient play to permit oi adjustment of the ball and socket joint. The upper end of the column 8 is closed by the plug 24.

The tubular column III is closed at its upper end by a removable screw plug 24 and sealed at its lower end inside the lower tank I2 to a pipe 40 which is positioned inside the tank I2. and discharges into the bottom of the tank at a point near the opposite Wall of the tank adjacent column 8'.

The tubular column 9 is closed at its upper and lower ends in a similar manner to column I0. Column 9 also carries a diaphragm 42 (see Fig. 2) at a point in the column inside the bottom tank I2 and somewhat spaced from the top of the tank I2. The column 9 is also slotted at 42' at a point in the column somewhat near the top oi the tank. This provides an outlet orice near the top of the tank.

With the piston 29 of the levelling foot 3l fully retracted inside the barrel 28, the ends of the four legs may all be ush with the bottom of the tank I2 or may protrude beyond the bottom of the tank I2 an equal distance and, being closed by plates, provide four columns capable of being set on a level foundation to give a vertical compound column.

Each of the

columns

8, 8', 9, and Il) is formed to receive a plug, such as 24, which may bereplaced by screwing tting 25 which may be connected to conduit 26 by the union fitting 21. When the plug 24 is in position, the top surfaces of the plug 24 are in one plane and coplanar with the top girders 41 of the cell positioned above tank II. The columns 9, I0, and 8, 8 are connected by I-beams 46 at the top oi the cell, and

columns

9, 8 and 8 and I0 are also connected by 5 similar I-beams 41 so placed as to present coplanar top ilanges. Tubular members may be used in place thereof.

The

cells

8, 8'. and 8" are similarly constructed to the pier cells with the following difference. In cell 8 one of the corner columns 4,8 (see Figs. 11 and 12) is of larger diameter than the tubular columns of the pier cells, for reasons to be described later. This column carries the levelling foot 31 and is otherwise constructed in a manner similar to that of column 8'. In the case of cell 8', the corner column 50 is of the same diameter as column 48 and of-the same construction as column 8'; columns 52 and 53 are of the same construction as I and 9, respectively.- In like manner, in cell 6 the

columns

48, 54, and54' correspond in' construction to 8, 9, and I0, respectively. Cell6" is constructed similarly to the cells 8 and 6' with the following differences: The

columns

55, 58, 51, and 58 are of a diameter intermediate the diameter of the

columns

50 or 48 and the

colums

8, 8', 9, and |0 for reasons to be further explained. Thus. column 55 is constructed similarly to column 6'; column 58 is constructed similarly to column 8; and column 56 is constructed similarly to column I0; and column 51 is constructed similarly to column 9.

The two cells and 5' are similarly constructed and are of a width substantially equal to the length of cell 6", 6', or 6, but are of length several times the length of each of said cells as indicated in the drawing. They are otherwise similarly constructed with the following differences: The

corner columns

66, 61, 68, 10, 1|, and 12 are of a diameter similar to the columns of the wing piers. The corner columns 65 and'69 are of a diameter similar to that shown for

columns

48 and 50.

Columns

61 and 10 are constructed in a similar manner to column 9, and

columns

66 and 12 are constructed similar to column 8; and

columns

68 and 1| are constructed in a manner similar to that of column |0.

The cell 4 is framed in the same manner as the cells 5 and 5 and constr-ucted similarly thereto except in the following respects. Instead of employing a single top and bottom tank, the top and the bottom are divided into two separate tanks, shown as 6|, 62. 63, and 64, employing four

additional columns

18, 19, 80. and 8| in addition to the

corner columns

13, 14, 15, and 10.

Columns

13 and 18 are constructed similarly to column 8', and

columns

14 and 19 are constructed similarly to column 8. Columns 8| and 16 are constructed similarly to column i0, and

columns

80 and 19 are constructed similarly to column 9.

Instead of using two separate top and bottom tanks, one top and one bottom tank with an opening through the tank for passage of the conductor pipe may be provided as by a circular cond-uit sealed to the top and bottom walls of the top and bottom tanks.

Positioned on one of the walls of the top and bottom tanks of cell 6 between the

columns

48 and 49 and in the wall of the upper and lower tanks of cell 6 between the columns 50 and 5| is the aligning joint formed in a manner similar to the joint for the pier cells (see Figs. l2 and 13). The detent I9 or the boss I8, whichever is used in the wall of the cells 6 and 6', is so positioned as to mate with the opposite members of the joint formed in the wall of the adjacent cell of the wing piers which is centrally positioned in the walls of the pier cells. Centrally positioned on the walls of the upper and lower tanks of cells 5 and 5' and of the upper and lower tanks of the cells 8 and 8' are the mating halves of such aligning Joints.

Centrally positioned on the walls of the upper tanks 8| and 82 and

lower tanks

83 and 84 between the

columns

14 and 8,0 and 18 and 15, respectively. is one element of an aligning Joint. The mating portions of the joint are positioned in the walls of the top and bottom tanks 85 between

columns

81 and 88 to mate with the joint elements on the walls of tanks 6| and 62. Cen- -trally of said upper and lower tanks and in the walls thereof between the columns 13 and 8l and between 7|8 and 18 are similar elements of the alignment joint which mate with suitably positioned elements in the walls of the upper and lower tanks of cell 5 between the

columns

10 and 1|. A similar joint exists between cell 6' and 4 by means of a joint whose elements are centrally positioned on the abutting walls of the upper and lowlertanks of cell 6" and the tanks 6| and 63 of ce It will be observed that the abutting walls of the cell 6" and the adjoining

cells

8 and 6 do not carry any aligning joints and are smooth so that, as will be explained later, cell 6" can be slid into position between cells 6 and 6'.

The tops of the columns of the

cells

6, 8', 8",

4, 5 and 5' are all closed by a plug such as 24 which, as in the case of the columns of the cells of the wing piers, may be replaced by the

iittings

25, 21, and pipe 26. With the plugs in place the top surfaces are coplanar with the top anges of the upper girders of the

cells

6, 6', 6", 4, 5, and 5'.

Mating flanges 20 are provided on all of the walls of the tanks at an external joint between the cells. Thus, a flange is provided at

columns

50, 52, 48 and 54' to mate with the cooperating iiange of adjacent tanks of the wing pier cells and with those of cells 5 and 5' positioned

adjacent columns

66 and 12, respectively. Likewise ilanges 20 are provided in the walls and at the diagonally opposite corner of the upper and lower tanks of cells 5 and 5' at

columns

68 and 1|, respectively, to mate with cooperating flanges on the upper tank 62 and lower tank 64

adjacent columns

15 and 16. Cooperative flanges are provided on the upper and lower tanks of cell 6" adjacent the

columns

55 and 58, respectively, to mate with cooperating flanges on the upper and lower tanks of cells 6 and 6' adjacent columns 5| and 49. An angle strap 28' is fastened in the corner between the tanks of the wing piers and the tanks of

cells

6 and 6.

It will be observed that a space 82 is provided between the tanks 6| and 62 and between tanks 63 and 64 in the tank sections, the purpose of which will be further described. The framing of cell 4 includes, at the elevation of the deck or platform floor, girders 83 which act as supports for the rotary table |06, as will be later described. Vertical girders 84 are provided as are connecting

girders

83, 81, and 88. At the elevation of the girders 84 are provided transverse and longitudinal girders for the cells 4', 5. 5', 6, 6' and 6", and cross bracing shown at 92, 93, 94, and 95, similar to the bracing in the pier cells'.

Transverse girders 83 cooperating with the

horizontal girders

86, 81, 88, 9|, 91, and 98 provide a support for the rotary table andfor the conduit and Christmas tree connections for the well, as will be further described. A surface conductor |02 is centrally positioned within the space 82 and is connected toblowout preventers |04 and |05 of conventional design. A mud outlet is provided at |08 in the surface pipe. The rotary 7 table is mounted upon the girders IL A drain pan Il extends across the whole of the space l2 and makes a tight Joint with the casing and a tight Joint at the walls of the upper tanks 0| and 02 and at the walls of the upper tanks of cells l and 6'. A ldrain I0' is connected to the drain pan al.

Floor |0| is positioned upon the top girders of all the cells and over the plugs 24 to form a continuous surface over the wing piers and over the top surface of

cells

4, 6', 6", 5, 6', and 4 with the latter surface raised above the elevation of the deck of the wing piers in amount and in a manner to be further described.

Extending the full length of the wing -piers 3 and adjacent the inner edge thereof next to 'slip 2 are two tracks |01 and |08 on which tracks are mounted beams |09 which ride on wheels ||0 which ride on the tracks. Two or more such beams are provided. Four symmetrically placed davits may be provided, two upon each wing pier. The davits carry blocks ||2 which cooperate with winches ||4 positioned in the derrick barge 3 in order to position the derrick barge on the beams |09. The drive connections for the Winches are not shown, but any suitable drive may be used as will be understood by those skilled in the art.

The derrick barge carries an extendible derrick composed of a bottom section ||5 and an extendible mast I I6 which may be telescoped within the bottom section and carried on the barge in a down position, one end resting upon a derrick support |26. The forward end of the lower mast section ||5 is hinged at ||8 upon a frame ||1 mounted on the starboard and port side 0f the bow section of the barge. The elevating truss I9 is pivotally hinged at I 2| to a slide operating on a track |2I mounted upon a leg of H5 and also pivotally mounted at ||9 to the frame I1. Link |22 is pivotally connected at |20 to one end 0i frame ||9 and at the other end to a travelling nut |23 mounted upon screw |23'. It will be observed that the hinge point ||8 is outside the barge and is so positioned that the derrick may be moved to an upright position shown in Fig. 5. The hinge points ||9 and |20 and the screws at all positions of the derrick are inside the barge.

A suible power plant |24, such -as a Diesel engine or Diesel-generator motor unit may be provided. A suitable drum |21 is employed for elevating the travelling block of the swivel, as is conventional for drilling operations. A suitable drum |28 may be provided as is employed for sand line operations.

Suitable containers for m'ud, cement, and suitable high pressure pumps may also be mounted 8 mounted on' additional barges, as will be described below.

The method of erecting submarine foundations according to my invention will next be described. When a suitable location has been found and the depth of water determined, as also the conditions of wave action in the region, cells are constructed in a manner previously described. The height of the cells is such that the distance between the submarine bottom and the bottom of the upper tank of the cells, when the cells are erected, will be such that, on the extreme wave action anticipated, the waves will break and pass underneath the bottom of the upper tank. The purpose is to avoid any uplifting force or to minimize the uplifting force which may be attamd from wave action.

The pressure and magnitude of wave action which may be anticipated are set forth in the Garth L. Young Patent No. 2,382,763 to which reference may be made for such discussion. It will be useful, however, to make observations in the area in which the structure is to be erected to determine the heightof the waves during storm action in order that thev best conditions may be obtained. Considerable information is available at most locations which may come under consideration, particularly for the drilling of oil, and if such information is not available, observations may be made in such area. Having established the desirable free board, that is, the height of the bottom of the upper tank from the mean high tide line, and the depth of the water, one can determinethe length of the cells which should be employed.

The cells may be constructed on land, launched with the upper tank and lower tank I2 full of air and oated in the water with the columns I' and 8 submerged and columns I0 and 0 above water. In the case of cells 4, 5. 5', 6, 6', and 6", they are oated in a similar position with the columns equivalent to I0 and 9 out of water. The cells, being a balanced system, will float on an even keel.

The following description illustrates a method of assembly of the cells of the wing piers where they are erected either as a first step in the construction of the structure illustrated or as a pier or foundation of a form other than illustrated herein. The cell is towed to the desired position by a tug, as is illustrated in Fig. 1'1. The tug |40 tows the cell by means of tow lines |4| connected to the submerged corners of the submerged section of the upper tank and with snubbing lines |42 connected. to the lower corners 'of the submerged section of the lower tank I2.

When the proper position has been reached by the tug, the tug is anchored by anchor |46. The plug 24 is removed from columns 9 and I0, and column I0 is connected to pipe 26 by fittings 2l and 26. Pipe 26 carries a valve 26' and a union tting 21' (see Figs. 4 and 4c). Fitting 21' is connected to a mud or water pump on the tug and water or mud is pumped down through column |0 through line 40 to the bottom of the tank I2 and thus weights that section of'the column which then sinks at its weighted end. The upper tank Il, being buoyant, is connected by line |4| to the tug |40. The snubbing line |42 is kept taut by a winch on the tug. The amount of water or mud introduced into the lower tank I2 is suillcient to overcome the buoyancy of the cell to a degree sulcient to permit it to sink at a controlled rate under the control of lines |4| and on the barge, if room is available, or maybe |42. The cell thus pendulums around the barge controlled by the tow line, the 4snubbing line being pulled in to assist the cell to become upright as it descends. During this operation the admission of mud through pipe 26 is controlled to maintain the necessary negative buoyancy to cause the cell to descend under controlled conditions.4 If deired, at this point and while the lines |42 and |4| Vare still attached, as indicated in Figs. 3 and 19, the plug 24 on column 8 may be removed and a line, such as 26, connected by fittings 21, 26', and 21A to the column 0 by means of the ntting 25 and mud jetted, by means of the mud pump on the tug, through the

jets

23 and 22 to scour out any loose mud or sand and permit the cells to settle to a rm foundation. When the cells settle in an upright position, as shown in Fig. 19, the lower tank I2 is filled with water or mud until the mud overows the top of the column 9.

At this point the hose connections are removed from

columns

8, 9, and and the plugs replaced. Sea bottom anchors |44 are set to each of the four corners of the cell (see Fig. 20) and the snubbing lines |4| and |42 are cast off. The anchor |46 is taken aboard and the tow barge cast on from the cells. Another tug, similar to tug |40, shown as |40a, now appears with a second unit and maneuvers it into position along side the erected cell, see Fig. 21. The tub |40 takes a tow on the upper cell of the iloating cell by means of tow line |41 and pulls the floating cell into position, shown in Fig. 22, with the tow lines |4| straddled over the` erected section by means of manual adjustment thereof. Line 46 is connected to the iloating lower cell and threaded through a sheave |48 temporarily mounted on one of the columns above the lower tank I2 by a clamp and passed to the tug |40l which takes the position in line with and in advance of the tug |48 (see Fig. 23). The sheave may be so mounted before launching or so mounted by divers when the cell is upright. The plugs are then removed from the columns 9 and |0 of the floating cell and pipe 26 connected in the manner previously described. Water or mud is now admitted into the lower tank of the column and by means of manipulation of line |40 and the snubbing line |46, as previously described, the column is erected and sunk into position. The buoyancy of the column is adjusted by controlling the amount of water admitted into the lower tank.

When the second cell is erect (see Fig. 24) a connection may then be made as previously de- I scribed for the jetting column 8, and by jetting the column in position it may be manipulated by lines 46, |40 and also, if desired, with the aid of divers, to align the second cell against the iirst cell, the alignment joints aiding in this operatic-n. The controlled buoyancy occasioned by the control of water in the lower tank permits of suificient buoyancy to manipulate the column into position. The aligning joints accurately align the top and bottom tanks against the adjacent top and bottom tanks of the previously erected cells so that the bolt holes in the flanges 20 are in alignment and divers may then bolt the lower tanks together and the upper tanks may also be bolted together. When this is accomplished the sheave |48 may be transferred to the newly erected cells. The lower tanks are lled with water or mud before casting off. The conduits 20 are cast off, plugs 24 replaced, the snubbing lines |4| and |46 are cast oil, and the anchors |44 set to the 10 all of the cells may be assembled to produce the structure previously described.

lIn erecting the structure shown in Figs. 1-16, inclusive, the cell 4 is rst spotted into position and centered, with the space 82 centered over the well location which has been previously determined.

Cells

6 and 6 are then erected with the aligning joints on the walls of thetanks 6|, 62, 63 and 64 cooperating with the corresponding elements of the aligning joints on the tanks of the cells 6 and 5' to accurately align the end cells in the manner described employing the method illustrated in Figs. 1'7-24, inclusive.

Cells

6 and 6 are then erected with the aligning joints on the walls of the cells 5 and 5 cooperating with those of cells 6 and 6' to accurately align 6 and 6'. The towing lines may be passedover the erected cells and sheaves in a manner similar to that illustrated, as will be understood by those skilled in this art. Cell 6" is now set into position in the space between the cells 6 and 6' and the cell 4, and, thus being centered, the aligning joints on the walls between 6| and 63 and on the tanks of 6" are brought into alignment. The cells are bolted together. The drilling platform isthus erected in the manner previously described, the cells having been bolted in the manner previously described.

If desired now the drilling platform can be levelled. For this purpose the plugs on the

columns

48, 50, 58, 65, 69, 13, 18, that is, all of the columns of the drilling platform which contain the levelling foot, are connected to a mud or water line for the operation of the levelling foot of each of the columns by connecting these columns by the fitting shown in Fig. 4c. The columns 5|, 49. 55, 14, 19, 66. and 12, that is, all of the jet columns, are also connected to a water or mud line by a similar tting. These cells are thus levelled by applying pressure to the pistons 0f the levelling foot and jetting selectively by the independent hydraulic line connected to each of the levelling foot columns and each of the jet columns. By providing a valve 26 on pipe 26 close to the fitting 25 and providing an additional iitting 21' for suitably disconnecting the hydraulic line from such fitting, the valves may then be closed with pressure on the line and the hydraulic system in the levelling foot maintained under pressure at the aligned condition. These ttings are thus left on the levelling foot when the system is erected and project through suitable holes in the deck. All other columns are closed by removing the tting 21 and replacing it with plug 24.

The wing piers mayl now be erected by moving into position cells adjacent the cells 6 and 6', centering with the aligning joints on the upper and lower tanks of 6 and 6 and bottom and top tanks of the cells of the wing piers. They are manipulated into position by tow lines in a manner similar to that described above with suitable adjustment of the tow lines to compensate for the progressive dimensions of the structure, as will be understood by those skilled in this art. The subsequent cells are now moved into position and joined seriatum to establish the wing piers, as will be clear from what has been said before. 'I'he wing piers may then be aligned by the jet and levelling foot of each cell which, it will be observed, are on the side of the cells adjacent the slip 2 and between the rails. The wing piers are thus levelled in the mannex` previously described for the drilling platform. Sea bottom four corners of the assembled cells. In this Way anchors of suitable character may be joined to the It willI be observed that in the erected platform with all the bottom tanks full of mud or with water, the cells are weighted at their lower end and the center of mass of the whole structure is below the horizontal median plane of the structure. Ihe low center of gravity together with the anchoring means previously described and the number of additional ones which may be set at various points in the structure establish a firm and stabe foundation. v As erected it may be considered temporary, in that the structure may b e disassembled in a manner which will be cle's' from what has been said before by a reverse operation, since it is a structure which is tied togetlmr by disassemblable Joints such as bolts. After levelling, in order to increase the stability of the foundation, gravel lor other illl may r be introduced underneath the bottom tanks. The

fittings

28, 21, etc., may, if desired, then be removed from the levelling columns 8' and the cap 24 set on the columns. a

Instead of moving each of the unit cells in separately, they may be preassembled in sections and moved in'. Thus, all or a portion of the drilling platform may be assembled on the shore, floated to position, and erected in a manner similar to that described for the unit cells. After erection it is settled and/levelled as previously described. The wing piers may be floated in sections or each in its entirety to a position and erected in a similar'manner and joined to the drilling platform as previously described.

With the structure in position and levelled, the top surface may be suitably decked and the machinery moved in, erected, and the conductor pipe |02 passed between the columns 84 and 85 in the space 82 between the tanks 0|, B2, 63, and 64, and jetted into position as is usual with such a pipe. 'I'he conductor pipe may becemented in position and the blow out preventers and Christmas tree units |04, |05 mounted and mud outlet tubing |08 set in the pan 99 in the manner previously described. The rotary table is positioned so that its drive shaft is axially aligned with the cell 4 for the purpose to be further described hereinbelow.

The barge H3 is then moved into the slip 2 until the Winches ||4 come underneath the davits The Winches ||4 then elevate the barge out of the water into a position above the wing piers, as shown in Fig. 6. The beams |09 are rolled into position underneath the barge ||3 by moving them along the tracks |01 and |08. The

the track |2|', the derrick is moved into erect position with the four legs of the lower section IIB resting on columns 55, il, 51, and 58, beingl the four columns of cell 0". The elevation of the drilling platform is in relationship with the platform of the wing pier and the elevation of the pivot points ||8' and ||,8 issuch that upon elevation the derrick legs rest upon the door of the drilling platform, with the legs on the girders connecting the columns of cell 8". By omitting the levelling foot connectionto column I8 and by iltting the plug therein, and by suitable spacing of the derrick legs and the columns, the legs of the derrick may be placed immediately above the columns of cell B". After erection suitablev guy wires, only one being shown in Fig. 5, may be connected to sea bottom anchors, or to the structure itself not illustrated, in order to in crease the stability ofthe derrick.

'I'he derrick construction may be conventional and its method of elevation may also be conventional or be such as is shown in my co-pending application Serial No. 691,717. The erection thereof and the extension of the derrick and its latching may be conventional or may be according to the device shownl in my co-pending application Serial No. 677,584. Such derricks are employed on land Ioperation of transportable umts such as trucks.

When the barge is in position, the shaft |38 is axially aligned with the shaft 8l' of the rotary table |08 and a connection may be made in between. 'I'he block, the swivel, and the drilling equipment may then be erected in conventional manner.

A separate mud barge and a separate tubing barge may be anchored along side the drilling platform. The mud barge may contain mud pumps and the usual mud equipment and connections for connecting them to the swivel and drill tubing.

barge is then lowered onto the beams |09. 'I'he beams |09 are then advanced until the barge reaches .the proper position on the platform to accurately locate the barge in position at a predetermined point in relationship to the drilling platform. A suitable' stop may be provided for this purpose on the wing piers. The barge and the beams |09 are then locked into position to prevent the movement of the barge from its predetermined position. The locking means, not illustrated, may be any locking means for this purpoa as will be understood by those skilled in the ar The screws |23 are then driven by means of the power plant |24, the gear train and shaft, and chain and sprocket assembly previously described to advance the nuts 23 from extreme lilo` sition at the bow end toward the stern. This withdraws the links |22, rotates the truss ||9 on its pivot H8'. and with the slide travelling down If 'during the drilling operation storms are encountered which make it unsafe-to leave the derrick erect, the drill ypipe may be suspended in position in the rotary table by slips, in a manner which will be well understood by those skilled in the art, and the travelling block removed from the swivel or lthe swivel removed from the kelly, as may be desired. The guy wires are disconnected from the derrick and secured to the platform. The telescoped derrick is lowered into its lower section and the derrick retracted into the position shown 'in Figs. 6 and 15. This lowers the extended section and reduces the hazards of operation in open waters. In the event, however, that the storm appears to be one which may be protracted and unduly severe, the derrick may be retracked onto the barge ||3 and-the barge lowered intov the water by unlocking the barge and moving it backward into position under the davits The barge is lifted off the beams |09 and lowered into the water and driven to safety and it may tow the mud and pipe barges with it to a safe location.

Should the drilling operation prove to be a failure, as a Wildcat operation well may be, the barge is removed as previously described and all the drilling equipment may be removed and the system disassembled by unbolting the sections in a manner previously described. e

A tow line having been connected to the unbolted section at the corners of tank adjacent the

columns

8 and 8 and a tow line being also y the slots 42 and the water is blown out through line 40 and columnV I0. By connecting an air line to the ,column 9 and permitting the water to be discharged through column I0, the air forces the water in column 9 down through the slot 42' into the top oi the tank I2, the mud and water discharging through line 40 and up column tow lines are then taken in so that the bottom tank is moved to the surface and the cell floated with the columns 9 and l0 out of the water.

After flotation, the conduits are disconnected from the columns 9 and I0 and plugs reinserted. The cells may thus be re-floated singly or in multiple sectional assembly.

If it be desired to convert this temporary loca.- tion into a permanent location, such as, for example, if oil is struck, divers are sent downto build forms underneath and around the bottom tanks encompassing the lower tanks of the various cells of the structure and the forms are iilled with concrete cement. Cementing under water may be carried out by standard and conventional procedure well known to those skilled in this art. The decking is removed over the tops of the columns 9 and i0 of the wing piers and the equivalent columns of the drilling platform? and the plugs are removed. Connections are made to the column I0 and the equivalent columns of the cells of the drilling platform for introduction of cement down column I0 and the other equivalent columns of the drilling platform. Cement ris pumped down these columns, displacing the -water or mud in the tank due to its higher gravity, the water being discharged through orice 42 and up column 9 and the equivalent columns of the cells of the drilling platform until the lower tank and columns are filled with cement. The tanks are this lled with cement and form a reinforced, continuous, solid concrete cement platform reinforced by the concrete poured into the forms set around it, as previously described.

While I have described 'a particular embodiment of my invention for the purpose of illustration, it should be understood that various modiilcations and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

I claim:

1. A unit cell for assembly into a cellular structure to be erected on a marine bottom, which comprises a plurality of elongated column members forming the longitudinal members of said unit cell, bottom and top closed flotation tanks mounted on said columns, one on each end of sad columns between said columns, cross bracing between said columns, and conduits connected to said bottom tanks and extending the longitudinal length of said cell for introduction and for removal of iluid from said bottom tanks.

2. A unit cell for assembly into `a cellular structure vto be erected on a marine bottom, which comprses a plurality of elongated column members forming the longitudinal members of said unit cell, bottom and top closed flotation tanks Asaid bottom tanks.

' l 14 mounted on said columns, one on each oi' said columns mounted between said columns, cross bracing between said columns, conduits connected to said bottom tanks and extending the longitudinal length of said cell for introduction and for removal of iluid from said bottom tanks, and a jet line extending the' longitudinal length of said cell and terminating near the bottom 3. A unit cell for assembly into a cellular structure to be erected on a marine bottom. which comprises a plurality of elongated column members forming the longitudinal members oi.' said cell, bottom and top closed otation tanks mounted on said columns, one on each end oi said columns mounted between said columns, cross bracing between said columns, conduits connected to said bottom tanks andv extending the longitudinal length of said cell for introduction and for removal of fluid from said bottom tanks, a-'levelling foct connected near the bottom of said bottom tanks, and means operable froml the other end of said cell for actuating said levelling foot.

4. A unit cell for assembly into a cellular structure to be erected on a marine bottom, which comprises a plurality of elongated column members forming the longitudinal members of said cell, bottom and top closed ilotation tanks mounted on said columns,'one on each of said columns mounted between said columns, cross bracing between said columns, conduits connected to said bottom tanks and extending the longitudinal length of said cell for introduction and for removal of fluid from said bottom tanks, a jet line extending the longitudinal length of said cell and terminating near the bottom of said bottom tanks, a levelling foot connected near the bottom oi.' said bottom tanks, and means operable from the otbter end of said cell for actuating said levelling foo 5. A unit cell for assembly into a cellular structure to be erected on a marine bottom, which comprises elongated tubular columns forming the longitudinal members of said cell, cross braces A. between said columns, a closed water-tight top tank mounted between one of the ends of said columns, a bottom tank mounted between the other of the ends of -said columns, one of said columns acting as a iluid inlet conduit into the bottom'tank, said inlet conduit communicating with the bottom tank, a second column acting as a fluid discharge conduit and communicating with the interior of said bottom tank, and means adjacent said top tank for closingr the ends of said columns. f

6. A unit cell for assembly ir to a cellular structure to be erected on a marine bottom, which comprises elongated tubular columns forming the longitudinal members of said cell, cross braces between said columns, a closed water-tight top tank mounted between one of the ends of said' columns, a bottom tank mounted between the other of the cnds of said columns, one of said columns acting as a fluid inlet conduit into the bottom tank, said inlet conduit communicating with the bottom tank, a second r-f said columns acting as a fluid discharge conduit and communieating with the interior of said bottom tank, a third of said columns open at one end adjacent the bottom of said bottom tank, a jet fitting attached to said open end, and means adjacent said top tank for closing the ends of the columns.

7. A unit cell for assembly into a cellular structure to be erected on a marine bottom, which comprises elongated tubular columns forming the longitudinal members of said cell, cross braces between said columns, a closed water-tight toptank mounted between one of the ends of said columns, a bottom tank mountedv between the other of the ends of said columns, one of said columns acting as a fluid inlet conduit into the botte-m tank, said inlet conduit communicating with the bottom tank, a. second of said columns acting as a iiuid discharge conduit and communieating with the interior of said bottom tank, means for closing the ends of said columns adjacent said top tank, a third of said columns open at the end adjacent the bottom of said bottom tank, a jet fitting attached to said open end, means for closing said third column, a piston mounted in a fourth of said columns near the end theres! adjacent the bottom tank, a pistonrod connected to said piston, a levelling foot connected to the piston rod and positioned near the bottom of said bottom tank, and means positicned adjacent said top tank for closing said columns.

8. A unit cell for assembly into a cellular structure to be erected on a marine bottom, which comprises elongated tubular columns forming the longitudinal members of said cell, cross braces between said columns, a closed water-tght top tank mounted between cne of the ends of said columns, a bottom tank mounted between the other of the ends of said columns, one of said columns acting as a iiuid inlet conduit into-the bottom tank, said inlet conduit communicating with the bottom tank, a second of said columns acting as a fluid discharge conduit. and communicating with the interior of said bottom tank, means for closing the top ends of said columns, a third column of said columns open at one end adjacent the bottom of said bottom tank, a 'jet iltting attached to said open end, means for closing said third column, a piston mounted in a fourth oi' said columns near the end thereof adjacent the bottom tank, a piston rod connected to said piston, a levelling foot connected to the piston rod and positiomd near the bottom of said bottom tank, and means adjacent said top tank for closing said columns.

mountsd on said columns, one on each end of said columns between said columns, cross bracing between said columns, conduits connected to said bottom tanks and extending the longitudinal length of said cell for introduction and fcr removal of uid from said bottom tanks, and a drilling conduit passageway between said top and bottom tanks.

10. A unit cell for assemblyinto a cellular structure to be erected on a marine bottom, which comprises a plurality of elongated column members forming the longitudinal members of said unit cell, bottom and top closed notation tanks mounted on said columns, one on each of said columns mounted between said colunms, cross bracing between said columns, conduits connected to said bottom tanks and extending the longitudinal length of said cell for introduction and for removal of iluid from said bottom tanks, a jet passageway between l1. s unit cell for assembly into a cellular removal oi' uid from said bottom tanks. a lcvelling footconnected near the bottom oi' said bottom tanks, means operable from the other end ot said cell for actuating said levelling foot, and a drilling conduit passageway between said top and'v bottom tanks.

12. A unit cell for assembly into a cellular structure to be erected on a marine bottom, which comprises a plurality of elongated column mem-k bers forming the longitudinal members of said cell, bottom and top closed notation tanks mounted on said columns, one on each oi said columns mounted between said columns, cross bracing between said columns, conduits connected to said bottom tanks and extending the longitudinal length of said cell for introduction and for removal of iiuidfrom said bottom tanks, a jet line extending' the longitudinal length oi' said cell and terminating near the bottom oi' said bottom tanks, a levelling foot connected near the bottom of said bottom tanks, means operable from the other end oi said cell for actuating said levelling foot. and a ldrilling conduit passageway between said top and bottom tanks.

13. A unit cell for assembly into a structure to be erected on a marine bottom, which comprises said iirst-named opening, certain of said columns forming a communication with the interior oi' each of said bottom tanks and'iorming fluid inlet conduits into said bottom tank, others of said columns communicating with the interior of each of said bottom tanks and forming i'luid outlets for said tanks, and means positioned adjacent said top tank for closing the tops oi' said columns.

14. A unit cell for assembly into a structure to be erected on a marine bottom, which comprises elongated tubular columns i'orming the longitudinal members, of said cell, cross braces i'or said columns, a plurality of top tanks mounted betweenone of the ends of said columns, said tanks being spaced to provide an opening therebetween,l

cross beams at the top of said' tanks adlacent the ends oi' said tubular columns, a plurality of bottom tanks mounted between the other o! the ends oi' said columns, said bottom tanks being spaced to provide an opening between said bottom tanks, said last-named opening being in registry with said ilrst-named opening, certain o! said columns forming a communication with. the interior of each of said bottom tanks and forming uid inlet conduits into said bottom tank, others oi' said columns communicating with the interior of each o! said bottomtanks and forming iluid outlets for' said tanks, others of said columns being open at i7 one end adjacent the bottom of said bottom tanks, a jet iltting attached to said open end, and means positioned adjacent said top tank for closing the tops of said columns.

15. A unit cell i'or assembly into a structure to be erected on a marine bottom, which comprises elongated tubular columns forming the longitudinal members of said cell, cross braces for said columns, a plurality of top tanks mounted between one oi' the ends of said columns, said tanks being spaced to provide an opening therebetween, cross beams at the top of said tanks adiacent the ends of said tubular columns, a plurality of bottom tanks mounted between the other oi' the ends of said columns, said bottom tanks being spaced to provide an opening between said bottom tanks, said last-named opening being in registry with said first-named opening, certain of said columns forming a communication with the interior of A each oi' said bottom tanks and forming iluid inlet conduits into said bottom tank, others of said columns communicatingr with the interior of each of said bottom tanks and forming iluld outlets for said tanks, additional columns forming levelling means for said cell. said levelling means comprising a piston mounted in said columns near the end thereof adjacent the bottom tank, a piston rod connected to said piston, a levelling foot connected to the piston rod and positioned near the bottom oi' said bottom tank, and means positioned adiacent said top tank for closing the tops of said columns.

i6. A unit cell for assembly into a structure to be erected on a marine bottom. which comprises elongated tubular columns forming the longitudinal-members of said cell, cross braces for said columns, a plurality of toc tanks mounted between one oi? the ends of said columns, said tanks being spaced to provide an opening therebetween, cross beams at the top of said tanks adiacent the ends oi" said tubular columns, a plurality of bottom tanks mounted between the other oi the ends of said columns, said bottom tanks being spaced to provide an openingr between said bottom tanks, said last-named opening being in registry with said i'lrst-named opening, certain of said columns forming a communication with the interior oi each of said bottom tanks and forming duid inlet conduits into said bottom tank, others oi said columns communicating with the interior oi eacli of said bottom tanks and forming fluid outlets for said tanks, others of said columns being open at one end adjacent the bottom oi said bottom tanks, a jet iitting attached to said open. end, additional columns forming levelling means for said cell, said levelling means comprising a piston mounted in said columns near the end thereof adjacent the bottom tank, a piston rod connected to said piston, a levelling foot connected to the piston rod and positioned near the bottom of said bottom tank, and means positioned adjacent said top tank for closing the tops of said columns.

17. A cellular marine structure to be erected on a marine bottom, comprising a plurality of cells constructed according to claim l, said cells being arranged one adjacent another, alignment joints between said cells, means for connecting said aligned cells together into a unitary structure.

18. A cellular marine structure to be erected on a marine bottom, comprising a plurality of cells constructed according to claim 4, said cells being arranged one adjacent another, alignment joints between said cells, means for c011- ld necting said aligned cells together into a unitary structure.

19. A cellular marine structure to be erected on a marine bottom, comprising a plurality o! unit cells comprising a plurality of' elongated column members forming the longitudinal members of said cell, bottom and top closed flotation tanks mounted on said columns, one on each end oi said columns mounted between said columns, cross bracing between said columns, conduits connected to said bottom tank and extending the longitudinal length of said cell for introduction and for removal oi iluid from said bottom tank and at least one of said unit cells comprising a drilling conduit passageway between said top and bottom tanks, said cells being arranged one adjacent another, alignment joints between said cells, means for connecting said aligned cells together into a unitary structure.

20. A cellular marine structure to be erected on a marine bottom, comprising a plurality of unit cells, said unit cells comprising a plurality of elongated column members forming the longitudinal members of said cell, bottom and tcp closed dotation tanks mounted on said columns, one on each end of said columns mounted between said columns, cross bracing between said columns, conduits connected to said bottom tank and extending the longitudinal length of said cell for introduction and for removal of fluid from said bottom tank, a jet line extending the longitudinal length oi said cell and terminating near the bottom oi said bottom tank, a levelling foot connected near the bottom of said bottom tank, means operable from the other end of said cell for actuating said levelling foot, at least one of said unit cells including a drilling' conduit passageway between said top and bottom tanks, said cells being arranged one adjacent another, alignment joints between said cells, means for connecting said aligned cells together into a unitary structure.

2l. A cellular marine stnicture to ce erected on a marine bottom, comprising a plurality ci unit cells, said unit cells comprising a plurality of elongated column members iormmg the longitudinal members of said cell, bottom and top closed flotation tanks mounted on said columns, one on each end of said columns mounted between sald columns, cross bracing between said columns, conduits connected to said bottom tank and extending the longitudinal length oi' said cell for introduction and for removal oi fluid from said bottom tank, a jet line extending the longitudinal length oi said cellV and terminating near the bottom of said bottom tank, a levelling ioot connected near the bottom of said bottom tank, means operable from the other end of said cell for actuating said levelling foot, one of said cells including a g conduit passageway between said top and bottom tanks, said cells being arranged one adjacent another, alignment joints between said cells, means for connecting said aligned cells together into a unitary structure.

22. A cellular marine structure to be erected on a marine bottom, comprising a plurality of unit cells, said unit cells comprising elongated tubular columns forming the longitudinal members of said cell, cross braces for said columns, a plurality of top and bottom tanks mounted between the ends of said columns, cross-bracing between said columns, at least one of said cells including a plurality of top tanks, said lastnamed tanks being spaced to provide an opening 19 therebetween, cross beams at the top of said top tanks adjacent the ends of said tubular columns, said last-named cells including also a plurality of bottom tanks mounted between the other of the ends of said columns, said last-named bottom tanks being spaced to provide an opening between said bottom tanks, said last-named opening being in registry with said first-named opening, certain oi' said columns forming a communication withthe interior of each of said bottom tanks and forming iluid inlet conduits into said bottom tanks, others of said columns communicating with the interior of each of said bottom tanks and forming iluid outlets for said tanks, means positioned adjacent said top tanks for closing the tops oi said columns, s`aid cells being arranged one adjacent another, alignment joints between said cells, means ior connecting said aligned cells together into a unitary structure.

23. A cellular marine structure to be erected on a marine bottom, comprising a plurality of unit cells, said unit cells comprising elongated tubular columns forming the longitudinal members of said cells, cross braces for said columns, top and bottom tanks mounted between the ends of said columns, cross bracing between said columns, at least one of said cells including a plurality oi! top tanks, said last-named tanks'being spaced to provide an opening therebetween, cross beams at the top of said top tanks adjacent the ends of said tubular columns, said lastnamed cells including also a plurality of bottom tanks mounted between the other of the ends of said columns, said last-named bottom tanks being spaced to provide an opening between said bottom tanks, said last-named opening being in registry with said rst-named opening, certain of said columns forming a communication with the interior of each of said bottom tanks and forming uid inlet conduits into said botl tom tanks, others of said columns communieating with the interior of each of said bottom tanks and forming uid outlets for said tanks, others of said columns being open at one end adjacent the bottom of said bottom tanks, a

jet fitting attached to said open end, means positioned adjacent said top tanks for closing y 20 the tops oi said columns, additional columns forming levelling means for said cell.'said levelling means comprising a piston mounted in said columns near the end thereof adjacent the bottom tank, a piston rod connected to said piston.

a levelling toot connected to the piston rod and v positioned near the bottom or said bottom tank, said cells being arranged one adjacent another, alignment joints between said cells, means for connecting said aligned cells together into a unitary structure.

' 24. A cellular marine structure to be erected on a marine bottom, comprising a plurality ot unit cells, said unit cells comprising elongated tubular columns forming the longitudinal members of said cells, bottom and top closed otation tanks mounted on said columns, one on each end of said columns and mounted between said columns, cross bracing between said columns, one of said cells including a plurality of bottom tanks mounted between the other oi the ends of said columns, said bottom tanks being spaced to provide an opening between said bottom tanks, said last-named opening being in registry with said first-named opening, certain of said columns forming a communication with the interior of each of said bottom tanks and forming fluid inlet conduits into said bottom tanks, others of said columns communicating with the interior of each of said bottom tanks and forming fluid outlets for said tanks, a levelling foot connected near the bottom of said bottom tanks, means operable from the other end of said cells for actuating said levelling foot, said cells being arranged one adjacent another, alignment joints between said cells, means for connecting said aligned cells together into a unitary structure.

JAMES MOON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,210,408 Henry Aug. 6, 1940 2,422,168 Kirby June 10, 1947