US3407768A - Offshore storage, mooring and loading facility - Google Patents

Description

Oct. 2, 1968 1F. GRAHAM 3,407,768

OFFSHORE STORAGE, MOORING AND LOADING FACILITY l INVENTOR. MoH/v E GPAHAM Oct. 29, 1968 J. F. GRAHAM 3,407,768

OFFSHORE STORAGE, MOORING AND LOADING FACILITY Filed Jan. l1, 1967 2 Sheets-Sheet 2 INVENTOR. c/oHA/ P. 64M/MM United States Patent O 3,407,768 OFFSHORE STORAGE, MOORING AND LOADING FACILITY John F. Graham, Mitchell, S. Dak., assignor to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Filed Jan. 11, 1967, Ser. No. 608,630 2 Claims. (Cl. 114-5) ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION 1. Field of the invention The invention relates generally to the storage of materials in a floating vessel and, more particularly, but not by way of limitation, it relates to water-borne apparatus for storing large quantities of petroleum products while providing mooring and loading facilities for transport tankers.

2. Description of the prior art The prior art includes various types of mooring buoys which can be permanently anchored in a body of water to receive liquid conveying pipelines from a producing well or a storage location to provide mooring and on-load ing rigging for transport tankers. The prior devices are limited since their primary function is that of a mooring station, securely positioned by suitable anchor means, which serves only as a transfer point between remote oil sources and a transport tanker. Thus, limitations arise as to the various types of oil sources, whether a producing offshore rig or a land-based storage tank and, in each case, their respective distances from the terminal or mooring facility. In addition to this, such buoy-type mooring facilities are very costly and this is accentuated when considering the fact that such equipment must be transported to and maintained in foreign waters and, in the event that the transfer or storage point is moved, the marine equipment must usually be left behind.

SUMMARY OF THE INVENTION The present invention contemplates marine apparatus which may be permanently positioned or secured at a selected anchorage to provide both a storage and a mooring station. The apparatus may consist of a oatable vessel which includes storage space and a rotational securing device mounted in an eccentrically located pivot way, extending vertically through said vessel such that the pivotal apparatus can be anchored to the sea bottom in fixed position while allowing the storage vessel to drift freely therearound. In its `more limited aspects, the invention contemplates that the storage vessels be constructed from seagoing hulls which may be salvaged from obsolete and/or deteriorated ships which are generally classified as salvage hulks.

Therefore, it is an object of the present invention to provide a water-borne apparatus to be positioned at a selected marine position to serve as a storage facility as well as a mooring and loading point for receiving export vessels.

It is also an object of the invention to provide such a sea-going storage apparatus by altering selected obsolete "ice ships or such as salvage hulks to include pivotable 4anchoring or securing apparatus as well as attendant pump and maintenance equipment, the conversion for total service being effected at minimum time and expense.

Finally, it is an object of the present invention to pro vide an offshore storage, mooring and ori-loading vessel which can be securely anchored in fixed position at one end while allowing the vessel to swing about the particular end position such that approach, tie up, etc., of export vessels can always be effected with minimal interference from vwind and sea and the simplest mooring line arrangements.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a pictorial plan View of a storage vessel performing its storage and mooring function in conjunction with an offshore oil rig and an export vessel;

FIG. 2 shows one form of conversion whereby a floating hulk or salvaged ships hull may be converted into a water-borne storage vessel;

FIG. 3 shows an alternative form of conversion, the pvot way being located vertically through the fantail of a salvaged hull;

FIG. 4 shows a vertical cross-section of a pivot way and one `form of pivotable securing structure movably positioned therein; and

FIG. 5 is a top view of the securing structure of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows one form of storage and mooring vessel 10 as it may be anchored in a body of water 12. Also, shown in the body of water 12 are an offshore oil rig 14 and an export ship or transport tanker 16 moored to storage vessel 10 in order to receive on-loading of oil therefrom. While subsequent discussion is directed primarily to the storage and handling of petroleum products, it should be understood that the storage vessel 10 is in no way limited to such usage, and it may be employed in the handling of various other forms of cargo.

The offshore oil rig 14 may be a conventional type constructed on a substructure 18 which is securely xed to the bottom 20 of water body 12. Petroleum products, such as crude oil, may then be flowed via the pipe fixture 22 and a flexible hose 24 along the water bottom 20 for some predetermined distance to the anchoring site of storage vessel 10. The distance will be determined from considerations of the depth of the water body 12 and the allowance of clearance area for storage vessel 10, a moored export ship 16, and the necessity of their swinging about the anchored point as will be further described.

The storage vessel 10 is formed to have a main body or hull 26 which embodies the storage or cargo holding volume and a forward extending bow portion 28 which is maintained above the surface of water body 12. The storage vessel 10 may be formed in various ways as will be further described below. For the description of FIG. l, it will sufce to say that the bow extension 28 defines a vertically extending pivot way 30 which retains 'a rotationally movable securing structure 32 therein.

The securing structure 32 may take any of several forms, its primary functions being to receive the oilcarrying hose 24 upward therethrough for connection to a conduit 34 which extends above the deck 36 (forecastle deck), the upperend of conduit 34 being attached to a delivery hose 38 by means of a sealed swivel connector 40. The swivel connector 40 may be a conventional form of such rotary fitting which is sealed as to the exterior surrounds by a suitable sealing ring or other such related assembly. The delivery hose 38 can then be controlled or directed about the deck of storage vessel for proper placement of liquids in storage tanks within hull 26. Conventional pump and valving equipment (not specifically shown) may be employed in such distribution.

The securing structure 32, rotational within pivot way 30, is secured to each of a plurality of anchor lines, such as anchor chains 42, 44, 46 and 48, which are axed to respective anchors 50, 52, 54 and 56 for the purpose of permanently and rigidly securing the pivot way 30 of storage vessel 10 over a preselected anchor site or position on bottom of water body 12. This may be in keeping with conventional permanent anchoring practice and, in one manner, the anchors 50, 52, S4 and 56 may be carried out by small craft and placed in quadratically arranged positions to secure pivot way for minimal movement with distributed securing tension in all directions.

The storage vessel 10 may be tted with an elevated Ventilator device 58, in accordance with marine regulations, as well as various other forms of operating equipment which may be permanently located on-board the vessel 10. A housing is shown as providing a space wherein the required operating pumps and control equipment may be located. Conventional types of bitts 62 may be located about the main deck of storage vessel 10 and a suitable cargo boom such as mast 64 and boom 66 and the attendant rigging may be utilized for handling the mooring lines, hoses, etc.

Thus, the transport tanker or export ship 16 is shown as being tied up to the storage vessel 10 by means of mooring line 68 secured to bitts 62 to receive the liquid loading hose 70 extending from storage vessel 10 for the purpose of on-loading petroleum product from storage. The stored petroleum product can be pumped up out of storage space in hull 26 and through the loading hose 70 by maens of a suitable array of diesel driven, high capacity pumps as may be located in the deck housing 60. As previously stated, the cargo boom 66 and its associated rigging as powered with conventional deckmounted winch machinery may be utilized in handling the loading hose 70 between the storage vessel 10 and vessels along side thereof.

As previously outlined, it is proposed that the storage vessel 10 can be constructed, or rather converted, with great savings in time and nancial outlay by altering existing hulls of seaworthy ships which for various reasons have been removed from service. That is, such ships may be partially damaged as from minor collision or other accident; they may be mothballed due simply to their obsolescence; or, a ship might only have sulered superiicial damage to its engines and other operating machinery. In any event, such salvage hulks are readily available in most port cities at a very low cost and selected ones of such hulks can be easily converted at very low additional cost to serve as storage vessels in accordance with the present teachings.

FIG. 2 illustrates a storage vessel 80, similar to storage vessel 10 of FIG. l, which has undergone one form of conversion. Thus, storage vessel has been converted from an original hull 82, including midships portion 84, bow portion 86 and stern portion 88, which might originally have been outfitted as a cargo ship, tanker or whatever. It is probably preferable for petroleum storage that salvageable hulks be selected from obsolete and damaged tankers since valuable additional service can be derived from existing ships equipment, i.e., pumps, deck equipment, cargo tanking, etc.

The stern portion 88 of hull 82 can be removed in accordance with conventional marine engineering practice by separation at a transverse bulk head 90 with addition of any necessary reinforcement of bulk head plating, athwartships members, deck grders, keel support, etc. The bow 86 of hull 82 is then prepared by cutting away a lower portion 92 which extends from stem 94 rearward to a weather bulkhead 96. The weather bulkhead 96 is formed as a heavy transverse sealing member to protect the cargo spaces within midships section 84 in the event of collision and can be further reinforced to withstand whatever the anticipated sea conditions. Thus, the bow portion 86 remains as a forward extending bow portion 98 which is cut away to be suspended above the normal and loaded water lines of vessel 80, its purpose being to provide a frame for location of the pivot point 100 vertically therethrough. A pivot way 102 is extended vertically through the bow extension portion 86 from the forecastle deck 104 through the main deck 106 and rst deck 188. Pivotal anchor structure, such as the securing structure 32 of FIG. l, would be rotatably secured within the pivot way 162 (as will be further described) to extend the respective, quadratically arranged anchor chains 42, 44, 46 and 48 to the sea bottom below.

Storage tankage or other such space as well as void spaces would be maintained in the mid portion 84 of the hull 82 and it is probably that much of existing old ships equipment would be retained for use in the various functions which would be carried on in connection with operation of storage vessel 80. Also, it is contemplated that some types of storage vessels might retain a limited amount of crews quarters, galley, etc.

FIG, 3 shows another type of storage vessel 110 which may be derived from a salvaged hulk by converting the hull 112 in a manner whereby a pivot point 114 is provided through the fantail. Thus, a lower run portion 118 of the fantail 116 is either hollowed out or entirely removed and a vertical pivot way 120 is cut downward from a poop deck 122 through the main deck 124 to be terminated at a lower deck such as first deck 126. Once again, securing structure (to be further described) will be located in the pivot way 120 to extend respective anchor chains 42, 44, 46 and 48 to the sea bottom below. Cargo space may be preserved by suitable conversion and rebuilding within the midships portion 128 and the bow portion (not shown in FIG. 3) may or may not be removed and strengthened with athwartships plating. It should be understood that in many cases salvaged hulk sections will be purchased with either forward or after portions already removed and this factor may dictate which of the FIGS. 2 0r 3 conversion modes is utilized.

FIG. 4 shows an enlargement of the bow extension 28 of storage vessel 10 (FIG. l) to illustrate One form of revolving anchor chain securing structure 32 which may be installed within the pivot way 30. Like parts also found in FIG. l have been similarly designated. The securing structure 32 is comprised of a circular pivot plate 130, a heavy steel disc, having an annular groove 132 cut about its under side and near the outer edge. The steel groove 132 is then filled with a plurality of ball bearings 134 such that the pivot plate 130` may be suspended thereon in a smoothly rotatable attitude. The forecastle deck 36 is cut through in the shape of a pivot hole 136 and a ring plate member 138, having a circular center -opening of the same diameter as pivot hole 136, is welded or otherwise secured to the deck 36 concentric with pivot hole 136 to provide reinforcement as well as a raceway upon which the pivot plate may revolve. A circular angle member 140` is then secured about the upper surface of said ring plate 38 in such manner that the inwardly turned upper flange 142 will retain the outer circumferential edge of pivot plate 130 and bearings 134 in movable contact for rotation on ring plate member 138.

The loading hose 24 is connected by a conventional type of coupling 144 to the conduit 34. Conduit 34 is secured vertically through a hole 146 which is cut through the axis of pivot plate 130. Conduit 34 is secured along the pivot axis by means of a lower collar 148 and an upper flanged collar 150 which are suitably secured, as by welding,` to the pivot plate 130. The conduit 34 is then connected through the swivel connector 40 to a delivery tube 38 which may lead to the pumping and valve equipment on board the storage vessel 10. As previously stated, this may be specially designed and installed equipment; however, it is contemplated that in many instances existing ships equipment found upon the various hulks will be utilized for further service aboard the converted storage vessel.

Referring also to FIG. 5, anchor securing may be carried out by means of quadrature arranged hawse or chain pipes 152, 154, 165 and 153 which are suitably secured through the pivot plate 130. Each of the chain pipes 152, 154, 156 and 158 is a conventional type of tubular structure which serves to pay out or direct movement of anchor chain and each is associated with a chain lock for securing a respective chain. Thus, quadraturearranged chain stoppers 160, 162, 164 and 166 are secured to the pivot plate 130 outward from and in radial alignment with the respective chain pipes 152, 154, 156 and 158.

Such chain stoppers are conventional marine fixtures which consist of a pair of parallel arranged upright side plates such as 168 and 170 which receive a securing pin 172 therebetween. Thus, as chain is tensioned upward through a chain pipe, a link can be locked within the side plates 168 and 170 by inserting the securing pin 172 through the chain opening or link center space. Such securing procedure is particularly applicable to the securing of anchor chain since the use of die-locked links will enable fast securing with little or no play remaining. It should be understood too that some applications may best call for the use of securing cables in quadrature or other symmetrical alignment and that, in this event, winch and tackle equipment can be secured to a swivel plate in similar manner to allow movement of the storage vessel therearound without twisting of the securing lines and oil loading hoses.

The FIG. 4 illustration depicts a bow portion 28 being cut away below the rst deck level and rearward to a collision-protective or weather bulkhead, storage space being formed from there aft. It should be understood that theshape and amount of cutaway of the lower bow portion may be varied in view of numerous considerations, a major consideration being to suspend the lower edge 180 of bow extension 28 above the water level at all times to avoid formation of barnacle coating, corrosion, ete. Thus, the pivot plate 130 may be rotationally secured to any of the upper decks, forecastle, main deck, first deck, etc., so long as sufficient reinforcement is provided. Also, the amount of freeboard 182 of forward bow extension 28 which is allowed to remain is entirely a design consideration. While the pivot way 30 is shown as being a generally cylindrical hollow cut vertically through the forward bow extensions 28, the shape is not important as long as sufficient clearance remains for the outwardly flaring anchor chains or lines which will be aligned downward therethrough. While pivot way 30 may include a barbette (not specifically shown) for weather protection, structural strength, or whatever, it is not a required part.

It should also be understood that the pivotable securing structure 32 of FIGS. 4 and 5 is merely one form of such structure and that various equivalents may be invoked in designing such apparatus. Very great cost advantage is derived from the fact that salvage hulks can be utilized to construct the storage vessels disclosed herein and that various ships equipment existing thereon can be reconditioned and reconnected for use on the vessel as it serves its storage and mooring function.

The foregoing discloses a storage vessel for offshore storage of fluid products which can safely receive an eX- port ship for mooring upon approach from downwind, the storage and moored vessels tendinlg to swing in alignment from a single pivot point. Such procedure enables the export ship and storage vessel to be tied by a simple mooring line arrangement, e.g., bow to stern; and, in tying up, the export ship can always approach a mooring position by a path of least interference into the wind and in alignment with the current dow. The utilization of such storage vessels greatly reduces the monetary outlay which is required in establishing petroleum product transfer points at remote installations where storage and periodic transport of the product has been necessitated.

Changes may be made in the combination and arrangement of elements as heretofore set forth in the specification and shown in the drawings; it beinlg understood that changes may be made in the embodiments disclosed without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

1. A method of converting a ship hulk having a bow and stern and a bulkhead between said how and the stern of said vessel and a storage area inside said hulk, to a floating storage comprising (a) removing the bow plates and hull supporting framework between said bow and a bulkhead and between the keel and a point above the water line of said hulk Iwhen fully loaded; (b) mounting a swivel anchoring and conduit 'means on the deck of said hulk over the portion of said hulk where said plates and supporting members have been removed in a manner so that the axis of said swivel is normal to the deck of said ship; and (c) connecting a conduit from said swivel means to said storage inside said hulk.

2. A method of converting a ship hulk having a bow and stern and a bulkhead between said bow and the sterm of said vessel and a storage area inside said hulk, to a floating storage comprising (a) removing the stern plates and hull supporting framework between said stern and a bulkhead and between the keel and a point above the water line of said hulk when fully loaded; (b) mounting a swivel anchoring and conduit means on the deck of said hulk over the portion of said hulk where said plates and supporting members have been removed in a manne-r so that the axis of said swivel is normal to the deck of said ship; and (c) connecting a conduit. from said swivel means to said storage inside said hulk.

References Cited UNITED STATES PATENTS 3,279,404 10/ 1966 Richardson 1140.5 3,335,690 8/1967 Busking 114-230 MILTON BUCHLER, Primary Examiner.

TRYGVE M. BLIX, Assistant Examiner.

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