US2399656A

US2399656A - Float

Info

Publication number: US2399656A
Application number: US567067A
Authority: US
Inventors: Edward R Armstrong
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-12-07
Filing date: 1944-12-07
Publication date: 1946-05-07
Anticipated expiration: 1963-05-07

Description

May 7, 1%@ E, R. ARMSTRONG FLOAT Filed Deo. fr, 1944 '7 Sheets-Sheet 2 May E946.

E. R ARMSTRONG FLOAT 7 sheets-sheet 5 F'iled Deo. '7, 1944 n 555.- 24 +1 ,i I

May 7 i945- E. R. ARMSTRONG l 3991556 l FLOAT Filed Dec. 7, 1944 '7 sheets-shew 4 jig@ a@ ,1.33 131 5g, 6 141 143 I 1.99 l J3 f 56 I *52 l l 1 l f6 .5; vi: C "i: I g r:

l l 64 l 4P J f r v \136 {In} l nil 67 l u1u 112 111 l mili J1-+lll I HII "0 l i- 133 12: :I

l l' I l Il I l I l f' i May 7, 1946- E. R. ARMSTRONG i 2,399,656

FLOAT Filed Deo. 7, 1944 7 Sheets-Sheet 5 May 7, 1946. E. R. ARMSTRONG FLOAT Filed Dec. 7, 1944 7 Sheets-Sheet 6 May 7, 1946. E, R. ARMSTRONG' FLOAT Filed Deo. '7, 1944 7 Sheets-Sheet 7 rig.

Patented` May 7, 1946` UNITED STATES FLOAT Edward R. Armstrong, Philadelphia, Pa. Application December 7, 1944, Serial No. 587,067

8 Claims.

This invention relates to floats and anchorage systems therefor, and has as its main object to provide for iloat stabilization, regardless of wind and wave conditions or changes in deck loading. While the invention is not limited in its application, an important field of usefulness is in offshore drilling operations, and for this reason the embodiment to be hereinafter described by way of example takes the form of an offshore drilling In accordance with the invention the iloat comprises essentially a platform structure or deck supported on a suitable number of columnar buoyancy units. Such units are. 4in themselves, of great effect in equalizing energy eiiects released by wave action, and the reasons for this are fully set forth in my prior Patent No. 1,892,125, granted December 27, 1932'. The anchoring means comprises a vertical system utilizing what I shall herein term weight anchors, since they rely primarily on their weight for anchoring eiiect. During well drilling` operations these anchors are bottomed and are so arranged as to enectively elim' inate roll and pitch of the iloat due to water disturbances, and consequently the working platform is maintained entirely stable. Since the float should be mobile in order to be able to proceed to a new drilling location upon completion of a well,

. I provide means for the adjustment oi' buoyancy effects so that while the anchors are able to hold the float submerged below its normal ilotation level during the building of a well, they are, nevertheless, liftable by the float to permit the vfree travel of the latter. This travel can be effected by the manipulation oi horizontal mooring cables which are provided.

.Without further general discussion, I shall describe the invention asjembodied in the structures shown in the accompanying drawings, in which: i

Figure 1 is 'a plan view of a float and mooring means in accordance with the invention.

Figure 2 is a side elevation of the structure shown in Figure l, a derrickbeing additionally shown.

Figure 3 is an elevation like that of Figure 2, but with parts in a diilerent relationship. i .f

Figure 4 is an end elevation of the structure as shown in Figure 3.

Figure 5 is a section substantially on line 5--5 of Figure 1.

Figure 5a is a plan view of an anchor.

Figure 6 is a fragmentary view on an enlarged scale showing in elevationreleasable guy anchorlng means which appear also in Figures 2 and 3.

Figure 'l is a section substantially on line 1-1 ofFlgllre 6. 4,

Figure 8 is a fragmentary view on an enlarged scale showing in elevation a braclretl which appears also in Figures 2, 3 and 5. v

Figure 9 is a section substantially on line 9-9 of Figure 8. l

Figure 10 is a fragmentary View on the scale of Figure 8 showing in vertical longitudinal sec-` tion a. releasable coupling which appears also in Figures 2 and 3. Figure 11 is a section substantially on line lI-II ofFigure 10.

Figure 12 is a'plan view of the structure oiFigure 1 on a smaller scale and showing horizontal mooring means in operative disposition.

Figure 13 is a side elevation'oi the structure fas shown in Figure 12. 4

Figure 14 is an end elevation of the iloat and anchorage means on the scale of Figures 12 and i3, but showing a different arrangement of horizontal mooring means, and

Figure 15 is a plan view of the arrangement shown in Figure 14.

Referring to the drawings, reference numeral i generally designates a fiat rectangular platform or deck structure here shown as. comprising three

sections

2l, 22 and 23 rigidly connected together. The platform structure comprises longitudinal truss members of which a side member is indicated at 2l, Figure 2, and transverse truss members, oi which an end member is indicated at 25, Figure 4. As shown in Figure 1, the center section 22 comprises longitudinal and transverse beams 28 and 21 defining a central symmetricallydisposed square 2B which includes further transverse members 29. Provided at the center of the square is a circular opening 30 through which the well building operations can be carried-out. Reference numerals 3l and 32 designate opposed parallei channel members secured to the top oi.' the platform in equally spaced relation from the longitudinal central plane of the platform, the channels receiving the wheels of a truck 33 on which is mounted a derrick 34 whose structure is open at the left, Figure 2. The lower end oi' the derrick is. angled to a transverse l pivot 3B supported on the truck 33 and rests against and is normally secured to triangular frame members 3B and -31 which are secured to the truck. Also mounted on the truck is a draw works 38 controlling

cables

39 and 40, of which the former is led beneath a guide pulley 4I mounted on the derrick. and thence to a crown 55 block 42 and a travelling block 43. Cable 40 Vruns to the top of the derrick, and when the derrick is unlocked from the frame members 35 and 31, it can swing to the left under the control of cable 40, and the travelling block .can accordingly swing outwardly of the derrick as permitted by the open structure at the left. Thus, by run-A, ning the truck 33 to the left-hand end of the rails Figure 2, the derrick can operate off of the left-hand end of the platform. In Figure 2 the truck is locked to the rails with the travelling block directly above the opening 30.

Secured beneath the deck structure 2l are, as here shown, eight columnar buoyancy units 44 to 5|, which may all be of the construction particularly shown in Figure 5. The buoyancy units are equally spaced longitudinally of the platform, the transverse spacing is the same as the longitudinal spacing, as here shown, and the unitsare symmetrically disposed with respect to the platform.

Referring to Figure 5, the unit 41 comprises a vertical cylindrical member 52 which extendsv through to the top of the platform and is rigidly secured thereto. A vertical cylindrical member 53 surrounds member 52 concentrically there-` with and has its upper end rigidly ilxed to the bottom of the platform. Below member 53 a further cylindrical member 54 surrounds member 52 `concentrically therewith, member 54 terminating downwardlyin a conical formation 55 which extends in to member 52 just above the lower extremity thereof and is sealed thereto.

Member v53 is divided into a numberof water-'- tight compartmentsit by horizontal annular partitions 56, and member 541s separated intocompartments by sealed partitions 51 fand 58 providing

compartments

59, 50 and 8|, of which the latter is water-tight. Compartment B9-has bottom openings as at 62, and compartment 69 has bottom openings asiat 63,v these openings being just above the partitions 51|a`ndj58, v respectively.' A pipe 64 extends from the toplof-compartment 59 to a valve 65, and thence to asouree ofcompressed air 86, the valve and source disposed in the, deck structure. The top of compartment 60 ylssimilarly connected by a pipe 61 with a valve 68'and source of compressed air 89. The valves 65 and 68 are ofthe fourway type, having a shut-oil position. a position in which the pipes 64 and 61 are open to the 5o atmosphere, and a position in which the pipes are connectedto the compressed air sources. In

the first position of the valves, with tanks 69 and f 60 empty, the tanks'will remain substantially so even though the -compartments are submerged.

-With the compartments submerged, the valves in lthe second-mentioned position will permit floodthe respective compartments throughout.

. Adjacent sides of the 'lower enlargements, as' at 54, of the buoyancy units have iixed thereto brackets 10 of the form particularly shown in Figures `8 and 9, these brackets being secured tc the `enlargements at the same level, which is preferably that of the partitions as-at 51. Each and 'l2 pierced to receive bolts 13 and 14 and to receive a bolt 15 on which is rotatable a pulley 18. 'I'he bolts 14 of opposed brackets engage ttings, as at 18, in which are seized the lends of diagonal guys as at 19, which run upwardly and are anchored to the bottom of the platform. This arrangement applies between all of the -buoyancy umts, except the

units

41 and 49, where a special releasable bracing system is provided for a Purpose which will later appear.v

Referring to Figures 2, 8 and 9,

columns

41 and 49 are equipped with opposed brackets 10 and have pivoted to their bolts 14 strut parts 80 and 8| having normally interengaged hooked ends 82 and 83, as particularly shown in Figure l1. Reference numeral 84 designates a sleeve which holds the ends in interengaged relation. By mov.. ing the sleeve to the right against a compression greturn spring 85, thejoint is uncovered and the 'parts 80 and V8| may be swung upwardly by pulling on

cables

86 and 81, Figure 2, which run-to [the deck. The sleeve can be moved to uncoupling vvrelation by pullingon a cable 88 which runs to the pulleys 18 .of the adjacent fitting 10, `and through a spacer98 which 'is engaged by a yoke will be tautened, and the slide retained by means of a pivoted dog |52, which can be releasedeby pulling on a control wire |03. 'I'he locking dog for'slide 9| is indicated by the reference numeral |04, Figure 2.

Referring to Figure l, the four buoyancy col- -umns at the left are connected by diagonal horizontally disposed ties |65 and |06, and the four columns at the right are connected by similar ties |01 and |58. Such ties are omitted at the center section, and, instead, diagonally arranged trusses |89 to ||2 are provided, these extending from the columns to the corners of the square structure 28 for 'the rigid suDpOrt of the center section against the weight of the derrick and other equipment.

As here shown, weight anchors ||3vto |2l,are associated with the buoyancy units, these anchors being all of the construction particularly shown in Figures 5 and 5a. Referring to that iigure, the anchor I6 comprises a frustoconical outer wall ||1 and an inverted frustoconical top wall ||8- providing a recess adapted to receive the lower conical end of the buoyancy column 41 with clearance for the projecting extremity of member 52. Spacer stripsl I9' are cured to the top wall ||8' in radial planes. A frusta-conical wall |28 is secured tothe lower edge of top wall ||8 and its'lower edge is connected with the outer shell ||1 through an annular wall |2|', so that a buoyancy tank or compartment |22 is provided. Wall |28 has secured thereto a reinforced bottom wall |23, to which is centrally fixed an uprightmember |24 bifurcated at its upper end and supporting a transverse pin |25. Wall |28' and bottom plate |23 detlne a compartment of the outer wall ||1 is interlorly rimmed by a -relatively narrow annulus |21, the connection bracket 18 comprises parallel vertical flanges 1| 75 being reinforced by gussets |28. Below wall |2| assauts elling block |32 by means of a hoisting cable |33, the travelling block having a hook |34 engaged.

with the pin |25. The upper end of cable |22 is led to a winch |35 mounted in the platform structure and eifective to pay out or take in the cable and to retain or lock the cable in any adjusted relation.

Reference numeral |30 designates a flexible hose connected at its lower end to a pipe |31 whose open end is disposed at the top of compartment |22, the latter being provided with bottom openings |38 in wall |20'. The hose is led up through the passage or shaft defined by member` 52 and over a pulley |30 to a drum |40 provided with a suitable drive for winding, unwinding, and locking. The drum end of the hone is in connection through a swivel coupling with a pipe |4| which' leads through a valve |42 to a source of compressed air |43. Valve |42 is a fourway valve, the same as

valves

85 and 58.

Reference numeral |44 designates a guy connected to the upright |24 of anchor IIB and running across to the pulleyl of the bracket on the adjacent side of column 45, and thence up.- wardly to a winch |45 mounted in the platform. The spacer strips ||9 provide clearance for the guy |44 so that the anchor ||8 can be pulled into contact with the bottom oi the column without cooking. A similar guy |45 runs to the bracket 10 on column 41, and thence to a winch |41. Similar diagonal guys are provided between all of the buoyancy columns and anchors, except

columns

41 and 49 and associated anchors. In Figure 4 the end diagonal guys are designated |40' and |48'.

In Figure 2' the anchors are all shown as being held against the bottoms of th'e columns and all ballast compartments are assumed to be empty. In such case the structure is in condition to travel to the point of use with the least possible draft, and the water line in this case will be at X. with a draft oi', say, 20 feet. The total height of the float and anchors in the relation shown in Figure 2 is 95 feet in the present example, and with this gure as a base, thc other proportions will be evident.

vAssuming uthat the water at the location to be drilled is not over about 65 feet deep, when the structure is in position the buoyancy tanks oi the anchors and the lower buoyancy unit compartments or tanks can be filled with water, with the result th'at the anchors will be bottomed in supporting relation to the iloat. The relation oi parts will remain the same as shown in Figure 2,

- units is such that when the tanks are illled with water, the total buoyancy eilect will oe over-balops after the anchors are bottomed. Therefore, with all buoyancy tanks fully ilooded and the anchor cables |38 tensioned, the iloat is ilrmly seated in a manner not to' be influenced by water disturbances.

In the situation lust discussed, the float rests on the anchors with the weight which is in excess of the total buoyancy effect of the buoyancy units.

- However, the ballast tanks of the buoyancy units may be blown out to restore the residual buoyancy in whole or in part, and, in that case, the anchors alone will serve as the hold down means. When it is desired to move the iloat, it is only necessary to blow out the anchors through the openings |30 which, it will be noted, are directed beneath the bottom plate |23. The issuing water serves to break the clinging effect. When the anchor tanks are fully blown out, each anchor, as contemplated in the present example, h'as a buoyancy effect of 50 tons'which supplements the buoyancy effect of the buoyancy units.

It will be evident that with the described relationship, it would be impossible for the float to lift the full weight of the anchors, which is 2000 tons as against the 1600 to 1300 tons maximum residual buoyancy of th'e float. However, by blowing out the tanks to a suitable extent they can bereadily lifted, and by blowing them out completely they add a considerable buoyancy effect of their own, as above-mentioned.

Where the water is deeper, as contemplated in Figures 3 and 4, whenthe location is reached the anchors may be iiooded and lowered to the bottom, and then the Winches operated to pull the iioat down so that the bottom of the platform is, say, 30 feet above the water level. Since the v anchor tackles are individually operable the platanced. Each anchor has a weight oi' 250 tons,

submerged, and, consequently, there is a total anchoring weight of 2000 tons which is considerably enhanced by the clinging eiect which develform can be pulled to an exactly level service draft or condition, regardless of bottom irregularities. With the ballast tanks of the buoyancy i units empty, there may be an upward pull as high as 250 tons per anchor and such a. tension eiect will maintain the float against any rolling and pitching, regardless of wave conditions. As the anchors are lowered the guys as at |44 and |46 are also paid out yand then tautened so that the buoyancy units are maintained directly above their associated anchor units. 4 the depth is assumed to be 165 feet and up to this depth the guys have a good stabilizing eiect. When greatly below this depth it is preferable to use the horizontal mooring cables whose arrangement will be later described.

In reaching a setting such as is shown in Figures 3 and ,4 it is more economical to iiood th'e ballast tanks of the buoyancy units along with the' ballast tanks .of the anchors, decreasing the re- 1 s ballast tanks empty.

As another possibility. the same residual iloat buoyancy of 1600 to 1800 tons may be assumed, but assume that the anchors are partly blown out so that each has an effective submerged weight of tons for an aggregate of 1000 tons. Under these circumstances the anchors would obviously not sumce, at least by weight alone, to

In. Figures 3 and hold the buoyancy units submerged below their normal notation level. However. under the as-l can be lifted without being blown at all, and, inthis case it would be the same as though anchors,

of fixed effects were'used.

In Figures 12 and 13 the float is shown as anchored in 300 feet of water and positioned by means of horizontal mooring cables |48 to |51 which extend from Winches at the corners of the float (see Figure 2) down to sheaves at. the top of the corner column enlargements and thence to anchors about 1200 feet away from the float, the cables lying in planes which substantially bisect the corner angles of the float, as here shown. In Figure 3 a well casing |52 is shown as lprojecting above the water to within a short distance of the platform. Assuming the well to have been completed and that the float is to be moved, the anchors are hauled up and the structure will rise but strut portions 80 and 8|, at least, will still be below the top of the casing. The strut portions are disconnected and swung upwardly and,

. if necessary, slides 9| and 92 are released and pulled together so that guys l! and 90 are slackened and can be picked up by a hook and lifted above the height of the casing. Then by manipulating the horizontal mooring cables the float can be moved laterally away fro'm the casing which is cleared by reason of the release of the strut members 80 and 8| and thev` cables 89 and 80. these being thereupon returned to operative relation. The horizontal cables maythen be used to move the Vrig to a new location, the anchors being re-set as required. l i

In Figures 14 and 15 a more'compiete horizontal mooring system is shown in that eight f cables |60 to |81 are provided, two extending from each corner at right angles to an end and side of the float respectively. The disposition is f shown for depths of one hundred, two hundred, e Land three hundred feet. At the one hundred foot depth the cables are anchored -three hundred feet away from the'float and six hundred feet away 'Aat the two hundred foot depth. At these depths 1 the cables can be supplemented by the guys as at |44' and |46' or the cables alone or theguys alone may be used. At the three hundred feet depth the cables are shown as anchored a thousand feet away from the float and the guys are omitted since at this depth they would be too steep for an adequate effect. Where the mooring cables are of such length that their weight would cause them to sag substantially I provide them with readily n attachable and detachable buoys |88 so that they are maintained substantially straight, as shown. Each cable runs to a separate winch on the float and the buoys are attached as the cables are paid out and removed as the cables 'are'takenin AWhile I have-shown an anchor associated with veach buoyancy unit it should be understood that this need not necessarily be always the case.

When the following claims mention submerging the buoyancy units below their normal flotation the vresidual buoyancy of the float as-determined by the condition of the float ballast tanks. I do not limit myself to the form and arrangement of parts herein specifically disclosed except as in the claims. 4

I claim:4

1. In combination, a float comprising a platform structure, vertical columnar buoyancy units beneath said platform structure for the .support of the same, weight anchors beneath said platform structure, vertically extending cables in connection with said anchors respectively.` Winches carried by said platform structure in connection with said cables for the independent con.. trol thereof including the locking thereof in any adjusted relation, each of said anchors including a buoyancy tank, and means for controllabilil flooding and emptying said tanks whereby said anchors can be adjusted so that when bottomed they are capable of holding said buoyancy umts submerged below the normal flotation level thereof orso that they areliftable by the buoyancy elect of said buoyancy units to permit movement of the float to another location, the height of the buoyancy units and the horizontal distribution of the buoyancy units and anchors being such and thehold-down capacity of the anchors being such as to enable the buoyancy units to be held 'so far below their normal flotation level and with such tension on the cables as to render the anchored float maintainable against rolling and pitching regardless of wave conditions with the Ibottom of the platform above the tops of the waves.

2. In combination, a float comprising a platform structure, hollow vertical columnar buoyancy units beneath said platform structure for the support of the same, weight anchors beneath said platform structure. vertically extending cables in connection with said anchors respectively, Winches carried by said platform structure in connection with said cables for the independent control thereof including the locking thereof in any adjusted relation, and means for controllably flooding and emptying said buoyancy units, said anchors being capable vwhen bottomed and said buoyancy units suitably flooded of holding said buoyancy units submerged below their normal notation level and being liftable by said buoyancy unit/s when the latter vare suitably emptied to permit movement of the float to another location.' the height of the buoyancy units and the horizontal distribution of the buoyancy units and anchors being such and the hold-down capacity of the anchors being such as to enable the buoyancy units to be held so far below their normal flotation level and with such tension on the cables as to render the anchored float maintainable against rolling and pitching regardless of wave conditions with the bottom of the platform above the tops of. the

waves.

3. In combination, a float comprising a piatform structure, hollow vertical columnar buoyancy units beneath said platform structure for the support of the same, means for controllably flooding and emptying said buoyancy units for the control of their buoyancy effect, weight anchors beneath said platform structure, vertically extending cables in connection with said anchors respectively. Winches carried by said platform structure in connection with said cables for the level, the level referred to is that established by they and the buoyancy units suitably flooded of f holding said buoyancy units submerged below 'assauts their normal notation level, and when they and the buoyancy units are suitably emptied being liftable by said buoyancy units to permit movement of the float to another location, the height of the buoyancy units and the horizontal distribution of the buoyancy units and anchors being such and the hold-down capacity of the anchors 'being such as to enable the buoyancy units to be lueld so far below their normal flotation level and with such tension on the cables as to tender the anchored oat maintainable against rolling and pitching regardless of wave conditions with the bottom of the platform above the tops of the waves.

4. In combination, a float comprising a platform structure, vertical columnar buoyancy units beneath said platform structure for the support of the same, each of said buoyancy units having a. vertical passage therethrough, weight anchors beneath said buoyancy units respectively, cables in connection with said anchors and disposed in said passages, Winches carried by said platform structure in connection with said cables for the independent control thereof including the locking thereof in any adjusted relation, each of said anchois including a buoyancy tank, and means for controllably ilooding and emptying said tanks, said anchors being capable when bottomed and their tanks suitably flooded of holding said buoyancy units submerged below their normal flotation level and when their tanks are suitably emptied being liftable by said buoyancy umts to permit movement of the float to another location, the height of the buoyancy units and the horizontal distribution of the buoyancy unitsand anchors being such and the hold-down capacity of the anchors being such as to enable the buoyancy units to be held so far below their normal notation level and with such tension on the cables as to render the' anchored float maintainable against rolling and pitching regardless of chors and disposed in said passages, Winches ear-` ried by said platform structure in connection with said cables for the independent control thereof including the locking thereof in any adjusted relation, said anchors being capable when bottomed and said buoyancy units suitablyfloored of holding said buoyancy units submerged below their normal flotation level and being liftable by said buoyancy umts when the latter are suitably emptied to permit movement of the float to anand the horizontal distribution of the buoyancy units and anchors being such and the hold-down capacity of the anchors being such as to enable the buoyancy units to be held so far below their normal flotation level and with such tension on the cables as to render the anchored float maintainable against rolling and pitching regardless of wave conditions with the bottom of the platform above the tops of the waves.

6. In combination, a float comprising a platform structure, vertical columnar buoyancy units beneath said platform structure for the support of the same, means for controllably flooding and emptying said buoyancy units for the control of their buoyancy effect, each of said buoyancy units having a vertical passage therethrough, weight anchors beneath said buoyancy units respectively, cables in connection with said anchors and disposed in said passages, Winches carried by said platform structure in connection with said cables for the independent control thereof including the locking thereof in any adjusted relation, each of said anchors including a buoyancy tank, and means for controllably -ooding and emptying said tanks, said anchors being capable when bottomed and they and the buoyancy units suitably flooded of holding said buoyancy units submerged below their normal flotation level, and when they and they buoyancy units are suitably emptied being liftable by said buoyancy units to permit movement of the float to another location, the height of the buoyancy units and the horizontal distribution of the buoyancy units and anchors other location, the height of the buoyancy units 1 being such and the holdfdown capacity of the anchors being such as to enable the buoyancy units to be held so far below their normal flotation level and with such tension on the cables as to render the anchored float maintainable against rolling and pitching regardless of wave conditions with the bottom of the platform` above the tops of the waves.

7. A float of the type described comprising a deck, a supporting structure therefor, a plurality of buoyancy units secured in spaced relation in and forming a part of the supporting structure, said buoyancy units in the aggregate giving the float substantial residual buoyancy when riding at service draft, some at least of said buoyancy units having a central shaft open at the bot--V tom, and hoisting means in said shaftsadapted to be connected to anchorage means.

8. A float of the type described comprising a deck, a supporting structure therefor, a plurality of buoyancy units secured in spaced relation in and forming. a part of the supporting structure. said buoyancy umts in the aggregate giving the float substantial residual buoyancy when riding means. Y 4

EDWARD R. ARMSTRONG.