US3722223A

US3722223A - Submersible single point mooring facility

Info

Publication number: US3722223A
Application number: US00165222A
Authority: US
Inventors: R Gratz
Original assignee: Continental Oil Co
Current assignee: ConocoPhillips Co
Priority date: 1971-07-22
Filing date: 1971-07-22
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27

Abstract

A submersible single point mooring facility for a bed of water which includes a mounting affixed to the bed of the body of water, a base mounted by means of a swivel to the mounting which permits 360* horizontal rotation of the mounting about the base, a buoy which is attached by means of a rigid arm to the base such that the arm is pivotally attached to the base and pivotally attached to the buoy, and means for floating the buoy or submersing the buoy such that the single point buoy can be floated during loading location and subsequently submersed to protect the buoy from accidental impact by passing ships or damage from surface ice.

Description

United States Patent 191 Gratz [451 Mar. 27, 1973 [75] Inventor: Ronald L. Gratz, Ponca City, Okla.

[73] Assignee: Continental Oil Company, Ponca City, Okla.

[22] Filed: July 22, 1971 [21] Appl. No.: 165,222

52 US. Cl. ..61/46, 61/48, 61/65,

9/8, 114/230, 141/387 [51] Int. Cl. ..B63b 21/00, B65b 3/00 [58] Field of Search .....61/46, 48, 46.5, 65; 114/230; 9/8 P, 8; 141/387 11/1967 Canada ..6l/46 Primary Examiner--Jacob Shapiro Att0rneyJ0seph C. Kotarski et al.

[ ABSTRACT A submersible single point mooring facility for a bed of water which includes a mounting affixed to the bed of the body of water, a base mounted by means of a swivel to the mounting which permits 360 horizontal rotation of the mounting about the base, a buoy which is attached by means of a rigid arm to the base such that the arm is pivotally attached to the base and pivotally attached to the buoy, and means for floating the buoy or submersing the buoy such that the single point buoy can be floated during loading location and subsequently submersed to protect the buoy from accidental impact by passing ships or damage from surface ice.

2 Claims, 3 Drawing Figures PATENTEDmzmn 3,722,223

F/G. l5

INVENTOR. RONALD L. GRATZ SUBMERSIBLE SINGLE POINT MOORING FACILITY BACKGROUND OF THE INVENTION Monomoorings, being located offshore and rather low in the water, are subjected to damage by ships passing in the vicinity of the mooring. Monomoorings also require an exceptionally good anchor system, since the mooring is free to float and thus be subjected to any wave action. Furthermore, in areas such as the arctic region where ice forms during a portion of the year, any mooring site is subjected to severe damage caused by the ice sheet being moved by the wind and by other forces. Since the mooring would be floating within the ice, the ice could easily shear any mount or cable system normally used to attach the mooring to the bed of the water.

PRIOR ART The closest prior art is a patent to W. F. Miller, No. 3,309,879, which discloses a loading system attached to the bed of the body of water and adapted to be raised or lowered by pulling on a line attached to the mooring system, thereby lifting it from the bed of water to the surface. The patent also discloses buoyancy being attached to the system in order to reduce the forces required in order to lift the assembly from the ocean bed.

An article in World Oil, page 88 of the July, 1970, issue discloses a single point mooring facility which has a rigid arm attached to the buoy and a pivotal arm attached to the base.

DESCRIPTION OF THE FIGURES Referring to the drawing, FIG. la illustrates the single point mooring facility or monomooring in a surfaced position for loading a ship, FIG. 1b illustrates the onshore facility for operating the flotation characteristics of said buoy, and FIG. 2 shows the same mooring facility in a submerged condition below a sheet of ice, for example.

DETAILED DESCRIPTION OF THE INVENTION Referring to the figures generally but in particular to FIG. 1, the monomooring is illustrated having a mounting attached to a base 11 through a swivel connection 12. A buoy 13 has a plurality of

arms

14 and 15 pivotally connected to the buoy at 14a and 15a, respectively, and to the

base

14b and 15b, respectively. A pipe is connected through a swivel connection 12 to a pipe 21 through a swivel coupling 22 to pipe 23, swivel coupling 24, and pipe 25 to a hose 26 which is con nected to a ship 27. Buoy 13 can be raised or lowered by expelling the water from an internal tank 16 in buoy 13 by means of any suitable gas such as, for example, compressed air.

Referring to FIG. 1b, a compressed air source 28 is connected through a valve 29 to either a vent 30 or a pipe 31 such that the valve in the first position will permit passage of compressed air from source 28 to pipe 31 and in a second position will permit venting of the pipe 31 to the atmosphere through pipe 30. Pipe 31 is connected coaxially through the swivel joint 12 to a pipe 33 which in turn is connected through a hose 34 to tank 16. An opening in the bottom of the tank 16 permits entry or expulsion of water therefrom.

The pair of

arms

14 and 15 tends to stabilize the platform and permit it to rotate so that the platform will seek a generally downwind position, making an approach and docking to the buoy relatively simple for a ship.

OPERATION In operation if, for example, the buoy is on the surface of the body of water as shown in FIG. 1 and one desires to sink the platform to the seabed, valve 29 is rotated to the second position,'v'enting the pressurized air in tank 16 to the atmosphere throughvent 30. As the pressure decreases, water will enter opening 16 filling the tank and causing the buoy to sink. As the buoy l3 fills with water it will gradually settle until it reaches the bed of the body of water as shown in FIG. 2.

Since the pair of

arms

14 and 15 are the same length, the buoy 13 must also settle in a level condition until it reaches the bed. When it is necessary to lift the monomooring from the seabed, valve 29 is moved to the first position, connecting pipe 31 to the compressed air source 28. Air pressure is then applied through pipe 31 to the buoy tank 16, forcing the water out of opening 40 and into the ocean or body of water. When the monomooring reaches the surface of the water, it will be in proper position for use.

If a thin layer of ice 50 as shown in FIG. 2 is present on the surface of the water, the mooring can be raised, impacting the bottom of the ice. In most instances the mooring will fracture the ice and raise to the surface.

In most instances the buoy may be marked with small marker buoys for information as to the location of same in order to protect the buoy against deep draft ships, particularly if the buoy is mounted in fairly shallow water.

It is obvious, of course, that the air under liquefied conditions could be stored on the base 11 so that a second swivel joint would not be needed. A remote electrically-operated valve could operate the source of air as previously described. Also, a remote pump could be mounted to remove the water from tank 16 by incorporating suitable water replacement means such as an air vent.

It is also obvious that modifications and changes in this invention can be made and still remain within the scope of the claims in this application as set out in the specification and appended drawing.

What I claim is: 1. A submersible single point mooring facility for a body of water comprising:

a mounting affixed to the bed of said body of water; a base; swivel means rotatably attaching said base to said mounting to permit 360 horizontal rotation of said mounting about said base; a mooring buoy; mooring buoy attachment means including a pair of vertically and parallelly-spaced, equal .length beams pivotally attached vertically to said base and said mooring buoy respectively; and means for submersing or floating said mooring buoy to cause said mooring buoy to either sink to said bed or float on the surface of the water respectively. 2. A mooring facility as set out in claim 1 wherein said means for submersing or floating said buoy comprises a source of compressed air, a valve connected to said source having a first and second position, a tank in said buoy, a pipe connecting said valve to said tank in said first position, and a vent, said vent connected to said valve in said second position, whereby when said 5 valve is in said first position, said compressed air can pass to said tank, and, when said valve is in said second position, the air in said tank can be vented.

Claims

1. A submersible single point mooring facility for a body of water comprising: a mounting affixed to the bed of said body of water; a base; swivel means rotatably attaching said base to said mounting to permit 360* horizontal rotation of said mounting about said base; a mooring buoy; mooring buoy attachment means including a pair of vertically and parallelly-spaced, equal length beams pivotally attached vertically to said base and said mooring buoy respectively; and means for submersing or floating said mooring buoy to cause said mooring buoy to either sink to said bed or float on the surface of the water respectively.

2. A mooring facility as set out in claim 1 wherein said means for submersing or floating said buoy comprises a source of compressed air, a valve connected to said source having a first and second position, a tank in said buoy, a pipe connecting said valve to said tank in said first position, and a vent, said vent connected to said valve in said second position, whereby when said valve is in said first position, said compressed air can pass to said tank, and, when said valve is in said second position, the air in said tank can be vented.