US3839977A

US3839977A - Floating marine terminal

Info

Publication number: US3839977A
Application number: US00184668A
Authority: US
Inventors: C Bradberry
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-09-29
Filing date: 1971-09-29
Publication date: 1974-10-08
Anticipated expiration: 1991-10-08

Abstract

A floating marine terminal for storage of petroleum, petroleum products or other liquids includes several cylindrical storage tanks positioned to float side by side. Structural member such as rigid tubular frames hold the tanks together and support a deck that overlies the cylindrical tanks. The terminal is moored to and may swing about a buoy which provides a terminus for submarine piping connecting with oil field facilities or installations ashore. Tank ships or tankers may breast along side the floating terminal to load or unload cargos.

Description

[11] 3,839,977 [451 oct. s, 1974 United States Patent [191 Bradberry [54] FLOATING MARINE TERMINAL [76] Inventor:

Carroll E. radberry, 26873 Moody SWW ia"""."gfygveDMsBf Rd., Los Altos Hin, Calif. 94022 mam "Wf- @sus @te a sep.29,1971

Appl. No.: 184,668

Attorney, Agent, or Firm-Flehr, Hohbach, Test, Albritton & Herben l [22] Filed:

ABSTRACT [52] U.S. 114/.5 T, 114/74 T FOREIGN PATENTS OR APPLICATIONS 4 Claims, 5 Drawing Flgures 1,582,795

PATENTE() UBT 81974 SHEU 10F 2 Mmmm msm l FLOATING MARINE TERMINAL BACKGROUND OF THE INVENTION This invention relates to docking and terminal facilities for tank ships or tankers; and more particularly, this invention provides a floating storage terminal that may be moored offshore in deep water to be accessible to large ships which cannot proceed to a dock in the shallower Water of most present day harbors. This invention is the subject of a disclosure document number 004,719 filed with the U.S. Pat. Office on Mar. 31,

In recent years, tankers have been built in ever increasing sizes for transporting crude oil and petroleum products. Tankers built for service in World War Il and earlier had capacities of the order of 140,000 barrels. More recently, it has been found to be more economical to transport crude oil and petroleum products in larger ships, since the cost of maintaining and operating the ships does not increase proportionally to the increase in the ships capacities. Therefore, a saving is afforded by building larger ships with greatly increased capacity, but with only nominally increased operating costs. Many present day ships have a dead weight tonnage of over 100,000 tons, and can carry in excess of 1,000,000 barrels of bulk petroleum or petroleum products. Such have a draft of 50 feet or more, and therefore can move into and out of only the largest and deepest of the worlds harbors.

The storage and transportation of crude oil and petroleum products is somewhat hazardous since a collision or other accident may result in spillage of oil to the detriment of the environment. It is therefore desirable that terminal facilities be provided for large tankers which are separate and apart from the usual -harbors near urban areas which are used for other types of ships, and which have considerable marine traffic and other activities.

It is an object of this invention to provide an improved marine terminal for tankers which may be located in deep water away from conventional harbors, and which may contain storage capacity that can be expanded or increased to serve even the largest of tank ships; and more particularly, it is an object to provide a floating terminal assembled of fabrication units including cylindrical storage tanks side by side such that the capacity of the terminal can be increased from time to time by the addition of further fabrication units.

It is a further object of this invention to provide an improved floating terminal facility for loading and unloading tankers wherein a buoy provides l a mooring for the floating terminal and (2) a terminus for a submarine pipeline which will connect between the storage tanks of the floating terminal and an oil field or shore facility; and more particularly it is an object to provide a pipeline connecting through the buoysuch that the terminal may swing around and assume -a favorable heading with respect to wind and to tidal currents.

SUMMARY OF THE INVENTION According to this invention, a floating marine terminal is constructed of cylindrical tanks which may be built in fabrication units of pairs and floated to the terminal site. At the terminal site, the fabrication units may be placed side by side and held together by welding of the structural members. A deck at least partially overlying the cylindrical tanks may provide for opera- Y' tions including tanker berthing, deck house(s) and aircraft landing. The deck will also provide weather proof space thereunder for piping, pumps, boilers and other machinery. The terminal is moored to a buoy which provides a terminus for a submarine pipeline to shore facilities. While most of the inner cylindrical tanks of the terminal will be used for storage of petroleum and other liquid products, the outer tanks can be used for ballasting the terminal with sea water. The same tanks will be continuously used for ballast, and sea water may be pumped into and out of the ballast tanks without polluting the surrounding'sea. Since the outboard tanks may be used for ballasting with sea water, the danger of pollution through collision and damage is minimized. A ship colliding with the terminal may rupture or damage an outer tank which can only cause a spillage of harmless sea water.

DESCRIPTION OF THE DRAWINGS FIG. r2 is aperspective view lookingdownwardly upon the assembled floating marine terminal;

FIG. 3 is a vertical transverse sectional view;

FIG. 4 is a side elevational view looking along the plane 4 4 of FIG. 3; and

FIG. 5 is an enlarged elevational view of the mooring buoy and a portion of the floating terminal to illustrate the mooring and piping connections through the buoy.

DESCRIPTION OF THE PREFERRED EMBODIMENT The basic element of this inventionl is a fabrication unit 10 (see FIG. l), which comprises two ormore cylindrical tanks 1l and 12 joined together and supported by longitudinal tubular frames 13 and transverse tubular frames 14. These frames form a rigid structure and support a deck 17. The diameterl and length of the tanks are determined by (l) the initial and estimated future storage capacity required for a specific terminal, and (2) the size of fabricating and launchingfacilities which are available within a reasonable distance from the terminal site. Indeed, the size of the fabricating and launching facilities is particularly important since there are Arelatively few Shipyards in the world capable of constructing and launching barges having a 1,000,000 or more barrel capacity to function as a floating terminal for loading and unloading large tankers. Presently, when large barges are constructed for this purpose, the shipyard is often thousands of miles from the terminal site; and the task of towing the barge to the terminal site is very time consuming and costly. The fabrication unit of this invention, being of smaller size, may be constructed at many different locations throughout the world. Therefore, these fabrication units may be built at a location relatively near to the terminal site, and the towing will be less time consuming and less costly. Furthermore, the manufacture of separate fabrication units provides a unitized construction such that the size of the terminal can be increased at later dates as the storage requirement is increased. Further units may subsequently be added to the existing units to increase the capacity of the terminal.

As shown in FIG. 2, the terminal is assembled by placing the fabrication units side by side laterally, and by placing further fabrication unit end to end longitudinally. The aft units and the intermediate units are constructed with flat reinforced bulkheads forming the tank ends. The bulkheads 15 may be flush with the ends of the longitudinal frames 13, or the bulkheads may be recessed somewhat to provide access for maintenance. The forward ends ofthe bow units have the cylindrical tanks constructed with rounded or bullnosed bulkheads 16 to reduce their resistance to water currents and such. The bullnosed bulkheads are set forwardly of the longitudinal frame members 13.

Intermediate bulkheads may be provided within the cylindrical tanks 11 and l2 to give the tanks mechanical strength and to prevent surging of the liquid products contained therein. These bulkheads may be solid to provide separation of various petroleum products; or the bulkheads may be perforated in cases where product separation is not required. As shown in FIG. 3, the

tanks

11 and 12 and the various compartments within the tanks are interconnected by piping 18 located in space between the tops of the tanks and the deck 17. Where it is necessary to have an enclosed dry area for machinery such as valve manifolds, pumps, engines, generators and boilers or for storage space, steel plates may bewelded between the rigid frame members.

The structural system makes use of rigid tubular frame members 13 and 14 which are generally simple to maintain and which offer less resistance to movement and wave action of water and to wind. It would likewise be possible to use other structural systems such as trusses or plate girders. When several fabrication units Y10 are positioned together, they can be permanately assembled together by means such as welding or bolting. It will be appreciated that the floating terminal shown in FIG. 2 comprises several individual fabrication units 10 which have been assembled together.

The deck 17 overlies at least a part of the area above the assembled fabrication units 10. The deck 17 provides an operational area for the berthing of tankers along side the terminal, and also provides an area for the landing of helicopters ar other aircraft that can use a limited runway. A deck house 19 may be provided for workers quarters, radio space, offices, instrument panels, etc. An antenna 20 may facilitate radio communication or a radio beacon for navigation of incoming tankers.

Mooring bits 2l are provided to moor tankers to both the port and the starboard sides of the floating terminal. Articulated loading arms 22 are provided to connect with the tanker manifold for taking or discharging cargo. Catwalks 23 are provided for access to mooring bits and mooring Winches 35 in the bow. Fenders 24 will protect both the ships and the terminal by cushioning any impacts therebetween. A small boat harbor 25 is provided by assembling the fabricationv units 10 such that the center units a somewhat forward of the outboard units. In addition to providing a protected berth for tugs, work boats and personnel launches, the positioning of the center units forwardly will improve the vaning characteristics such that the floating terminal will assume a natural heading with regard to winds and currents.

The floating marine terminal of this invention may comprise fabrication units having cylindrical tanks approximately 40 feet in diameter and approximately 400 feet long. As indicated heretofore, the units will be fabricated in a shipyard, launched and floated, and then towed by tugboats to the terminal site. By constructing two or more tanks in a unit, a degree of stability may be achieved since each unit will move through the water similarly to a double hulled boat. At the terminal site, the fabrication units 10 will be assembled into the complete terminal. FIGS. 2, 3 and 4 illustrate a terminal having six fabrication units with two cylindrical tanks in each unit-a total of 12 tanks. The fabrication units have been arranged with three units side by side and two units end to end.

The floating terminal is moored to a buoy 31 which is held in place by guy cables 32 attached to anchors 33. There are usually four or six anchors 33 holding buoys of this type, and the cables may in fact be `heavy chains as indicated by the drawings. The buoy is constructed with a swivel or rotary top 34. Mooring lines 36 and a transfer hose 37 are connected to the rotary part of the buoy 31 and may rotate through 360 degrees as the floating terminal takes its `heading into the wind and current. A submarine pipeline 38 conects to shore facilities or offshore production facilities, and is connected to the buoy 31 by a hose 39. The hose 37 connects between the buoy 3l and a riser pipe 40 which connects withv the piping 18 and the tanks of the terminal. Usually there are two mooring lines 36 between the buoy 31 and mooring Winches 35. Although a single hose 39 and submarine pipeline 38 is shown in FIGS. 4 and 5, it will be appreciated that further hoses and pipelines may be connected to the buoy 3l if it is necessary to transport additional petroleum products. When this floating marine terminal is used for loading tank ships with crude oil from an oil field, a single submarine pipeline 38 is usually sufficient. However, a floating terminal may be located offshore from a refinery; and as many as three pipelines may be used for the different petroleum products produced by the refinery.

For a maximum stability, particularly in high seas or rough weather, the marine terminal of this invention should float in a semi-submerged condition. To properly achieve this condition, certain ones of the tanks or portions of certain tanks are designated as ballast tanks. During times when the oil storage tanks are relatively empty, water ballast must be taken aboard to increase the weight for partially submerging the terminal. During other times when the storage tanks are nearly full, the water ballast is pumped out to prevent the terminal from sinking. Since the ballast compartments are separate from the oil compartments, the water ballast is never contaminated with oil; and therefore, the water ballast may be pumped out without polluting the sur pumped into the sea from the outer tanks. However, if a ship accidently collides with or rams the floating marine terminal, the outboard tanks will be the ones to suffer damage from the impact. lf the outboard tanks are damaged, any resultant spillage will be harmless sea water, and the danger of polluting the sea from such a collision will be minimized.

Since the ballast requirements of a specific terminal will be determined by the total weight of the structure and by the specific gravity of the liquid products to be stored, it may not be necessary in all installations to use the total volume of the outboard tanks for ballast. Where this condition exists, the outboard tanks may be compartmented longitudinally by a bulkhead 42. Alternatively, a smaller tank 43 may be installed inside and concentric with the larger cylindrical tank. To avoid the posibility of pollution in the event of a collision, which may breach the tank, the outside space 44 of the tank separated by the bulkhead 42 will be used for ballast and the inside space 45 will be used for the petroleum product. If a smaller concentric tank 43 is used,Vy

the product will be contained within the smaller center tank 43, and the anullar space surrounding the small tank 43 will be used for ballasting. In either case, the compartment containing the product will be protected from damage by its positioning.

The invention is claimed as follows:

1. A floating storage terminal for loading and unloading tank ships, said terminal comprising a plurality of fabrication units secured in side by side relation to form said terminal, said units each comprising a plurality of fluid storage tanks disposed in side by side relation, a structural framework interconnecting said tanks to retain the tanks in side by side relation, said framework comprising rigid spacer elements interposed between and distributed along corresponding sides of the tanks of each said unit, upwardly extending rigid support members mounted upon said spacer elements, additional upwardly extending rigid support members mounted to protrude upwardly from theoutboard sides of said unit, the upper ends of said members lying in a common plane, transverse and longitudinal rigid elongate members secured to the upper ends of said rigid support members to form a support plane, a work platform supported upon said support plane, and means adapted to form a flexible fluid connection between said tanks and an offshore loading buoy for loading and unloading said tanks.

2. A floating storage terminal for loading and unloading tank ships according to claim l wherein one of said units is disposed substantially amidships and protrudes ahead of the others of said units, the stern end of said one unit being advanced forwardly of the stern of the others of said units to provide a sheltered harbor astern of said storage terminal defined by an opening amidships extending forwardly from the stern of said terminal.

3. A floating storage terminal for loading and unloading tank ships, said terminal comprising a plurality of fabrication units secured in side by side relation to form said terminal, each of said units comprising a plurality of elongate fluid storage tanks, means securing said tanks in side by side fixed relation, and a rigid support framework carried above said tanks, saidframework being adapted to be joined in side by side relation to others of said units to define a work plane, and a work platformsupported upon said work plane, one of said units being disposed-substantially amidships and protruding ahead of the others of said units to be adapted to be coupled to a buoy and permit the terminal to obtain a favorable heading with respect to wind and currents, the stern portion ofsaid one unit being advanced ahead of the stern portion of the other units to define a sheltered harbor region astern of said one unit and between units flanking said one unit.

4. A floating storage terminal for loading and unloading tank ships according to claim l further comprising means extending longitudinally within the outboard tanks of the outboard units and serving to provide a compartment adapted to be flood-ed with water, said compartment being disposed between the outboard hull of the outboard tanks and an interior compartment adapted to be employed in storing fluid other than water, whereby said outboard compartment serves to minimize the risk of leakage of the stored fluid into the ocean as a result of collisions of the outboard side of the terminal with ships docking alongside.

l l =l lf

Claims

1. A floating storage terminal for loading and unloading tank ships, said terminal comprising a plurality of fabrication units secured in side by side relation to form said terminal, said units each comprising a plurality of fluid storage tanks disposed in side by side relation, a structural framework interconnecting said tanks to retain the tanks in side by side relation, said framework comprising rigid spacer elements interposed between and distributed along corresponding sides of the tanks of each said unit, upwardly extending rigid support members mounted upon said spacer elements, additional upwardly extending rigid support members mounted to protrude upwardly from the outboard sides of said unit, the upper ends of said members lying in a common plane, transverse and longitudinal rigid elongate members secured to the upper ends of said rigid support members to form a support plane, a work platform supported upon said support plane, and means adapted to form a flexible fluid connection between said tanks and an offshore loading buoy for loading and unloading said tanks.

2. A floating storage terminal for loading and unloading tank ships according to claim 1 wherein one of said units is disposed substantially amidships and protrudes ahead of the others of said units, the stern end of said one unit being advanced forwardly of the stern of the others of said units to provide a sheltered harbor astern of said storage terminal defined by an opening amidships extending forwardly from the stern of said terminal.

3. A floating storage terminal for loading and unloading tank ships, said terminal comprising a plurality of fabrication units secured in side by side relation to form said terminal, each of said units comprising a plurality of elongate fluid storage tanks, means securing said tanks in side by side fixed relation, and a rigid support framework carried above said tanks, said framework being adapted to be joined in side by side relation to others of said units to define a work plane, and a work platform supported upon said work plane, one of said units being disposed substantially amidships and protruding ahead of the others of said units to be adapted to be coupled to a buoy and permit the terminal to obtain a favorable heading with respect to wind and currents, the stern portion of said one unit being advanced ahead of the stern portion of the other units to define a sheltered harbor region astern of said one unit and between units flanking said one unit.

4. A floating storage terminal for loading and unloading tank ships according to claim 1 further comprising means extending longitudinally within the outboard tanks of the outboard units and serving to provide a compartment adapted to be flooded with water, said compartment being disposed between the outboard hull of the outboard tanks and an interior compartment adapted to be employed in storing fluid other than water, whereby said outboard compartment serves to minimize the risk of leakage of the stored fluid into the ocean as a result of collisions of the outboard side of the terminal with ships docking alongside.