US3674062A

US3674062A - Offshore loading and unloading of tankers

Info

Publication number: US3674062A
Application number: US71588A
Authority: US
Inventors: Frederick S Ellers; Sam W Small; Luis B Serpas
Original assignee: Bechtel International Corp
Current assignee: Bechtel Group Inc
Priority date: 1970-09-11
Filing date: 1970-09-11
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: CA933837A

Abstract

The present invention provides an improved ship mooring device for ships and other vessels whereby fluids may be loaded or unloaded while the ship is moored offshore. In accordance with this invention, a monolithic anchor structure is secured to the sea bottom at a suitable location. Mounted upon the anchor is a swivel structure which is movable through 360* . Attached to the swivel structure is a tubular swing arm which, in accordance with this invention, has a neutral or nearly neutral buoyancy. The arm, however, is held by drag weight and buoyant hose in a generally horizontal position and, by means of the swivel, can swing over the sea bottom in a substantially horizontal plane through 360* . Attached to the end of the tubular swing arm is a flexible hose, one end of which is secured to the end of the swing arm and the other end is adapted to be connected to a suitable connection on the vessel so that a fluid may be transferred through the hose, the tubular swing line, the swivel and a submarine line extending to a shore location. When not in use, the hose is supported by encasing buoys so that the hose assumes an S configuration in a vertical plane. A second buoy is attached to the free end of the hose so that it may be readily picked up by the vessel.

Description

United States Patent Ellers et al.

[ 1 July4, 1972 [54] OFFSHORE LOADING AND UNLOADING OF TANKERS [73] Assignee: Bechtel International Corporation [22] Filed: Sept. 11, 1970 [21] Appl. No.: 71,588

Primary ExaminerHouston S. Bel], Jr. AtlomeyEckhoff and Hoppe [5 7] ABSTRACT The present invention provides an improved ship mooring device for ships and other vessels whereby fluids may be loaded or unloaded while the ship is moored offshore. In accordance with this invention, a monolithic anchor structure is secured to the sea bottom at a suitable location. Mounted upon the anchor is a swivel structure which is movable through 360. Attached to the swivel structure is a tubular swing arm which, in accordance with this invention, has a neutral or nearly neutral buoyancy. The arm, however, is held by drag weight and buoyant hose in a generally horizontal position and, by means of the swivel, can swing over the sea bottom in a substantially horizontal plane through 360. Attached to the end of the tubular swing arm is a flexible hose, one end of which is secured to the end of the swing arm and the other end is adapted to be connected to a suitable connection on the vessel so that a fluid may be transferred through the hose, the tubular swing line, the swivel and a submarine line extending to a shore location. When not in use, the hose is supported by encasing buoys so that the hose assumes an S configuration in a vertical plane. A second buoy is attached to the free end of the hose so that it may be readily picked up by the vessel.

6 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION As transportation economics dictate the use of larger and deeper draft liquid transporting vessels, they are unable to enter most enclosed harbors and generally must load and unload their cargo in open water. In addition, the forces of wind, wave and current in open water are so great that it is not feasible to moor these large vessels in fixed, spread moorings such as is common with smaller vessels.

An interim solution has been the use of large single surface mooring buoys involving long (700 feet plus or minus) hoses from the bottom into the buoy and thence to the vessel manifold amidships. These long hoses must necessarily be fabricated in relatively small diameters and hence seriously limit the rate at which liquid can be loaded or discharged. In addition, the action of the sea imparts a violent motion to the surface buoy which leads to rapid deterioration of the attached loading hoses.

The present invention provides a unique and efi'ective means of eliminating:

a. loading rate restrictions by decreasing the length of flexible hose; and b. deterioration of hose due to the violent action of the sea by attaching it to a swinging arm below the ware base.

SUMMARY OF THE INVENTION It is generally the broad object of the present invention to provide a new and improved ship mooring device enabling fluid to be transferred at high rates from or to a vessel.

A further object of the present invention is to provide a simplified form of loading mechanism for a vessel of which the major portion is submerged in the sea essentially below the wave base so that is is not exposed to the unceasing and sometimes violent action of surface waves.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a moored vessel with the loading apparatus ready to be picked up and attached to the ship.

FIG. 2 is a fragmentary side elevation showing a ship moored and with the loading and unloading line connected and in place.

F IG. 3 is a cross section of the swing arm.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a suitable anchor 6 is secured permanently in a fixed position to the sea bottom at a suitable depth. The anchor is connected by a pipeline 7 to a shore installation for the fluid being handled. The anchor includes an upstanding central member 8 to which a flexible chain or other anchor line 9 is attached and which extends to a buoy 11. Mooring lines 12 are extended from the buoy 11 to the how 13 of a tanker, generally indicated at 14. Thus the tanker is free to swing 360' about the anchor 6 depending upon the direction of wind and tide and wave action.

In accordance with this invention, a swivel structure 16 adapted to swing 360 is mounted upon the anchor 6. Attached to the swivel structure 16 is a tubular yoke 17 which is connected through the swivel structure to the pipeline 7. Extending forwardly from the yoke is a tubular swing arm 18 which is so constructed as to have a neutral or nearly neutral buoyancy. Buoyancy control is provided by the use of a combination of buoyant materials or devices and ballast materials or devices which are either integral with or afl'ixed to or attached to the arm. Thus as appears in FIG. 3, the swing arm includes a large central fluid-flow pipe 31 with two smaller pipes 32 running along each side. The three pipes are enclosed in a casing 33 while the space between the casing and the pipes is filled with a light foamed solid 34, such as styrofoam or polyurethane. A suitable fluid is placed in the pipes 32 to provide the requisite buoyancy such as a heavy salt solution or a light of the buoyant hose and hold the swing arm generally horizontally.

Secured to the outboard end of the swing arm is a flexible hose 21. This is of such a length that, when not in use, the hose extends in an S-shaped loop in a vertical plane. To achieve this, that portion of the hose directly attached to the swing arm, which portion is designated as 22, has a positive buoyancy while the other portion of the hose 23 has a negative buoyancy whereby the hose achieves the S-shaped configuration provided by attached units of styrofoam or polyurethane 25 when not in use. Positive buoyancy is provided to the hose in portion 22. A buoy 24 is attached by line 26 to the end of hose portion 23 so that the hose may be lifted vertically and attached to a suitable loading and unloading connection 27 provided on the tanker or vessel, as is indicated in the dotted line portion of FIG. 1.

A normal operation of the device when used to load or unload a ship is, first, to swing the boom to one side; then the ship approaches from a clear side and connects or moors to the buoy 11 by bow lines; then the boom is brought around until it is parallel to the ship; then the ship picks up buoy 24 and lifts loading hose 23 until it can be connected to the ships manifold 27; the fluid to be loaded arrives at anchor 6 by submarine pipelines, thence through the swivel or flexible joint to the tubular arm and thence to the ships tanks by the hose and manifold connections on the ship.

The structure of the present invention may be utilized in: loading or unloading of marine tankers; loading or unloading of marine bulk carriers; in port operations where waves or currents preclude the use of piers; and in port operations where bottom or other physical conditions preclude the use of marine anchorages.

The present invention permits the loading and unloading of ships under sea conditions which make the use of conventional equipment dangerous or impractical. It also permits ships to moor without the utilization of tugs. Also by utilization of the present invention, ships can moor and transfer cargo without the necessity of line handling launches normally necessary for marine anchorages. The device also permits vessels to readily change position so as to lie in the most favorable direction while loading or unloading cargo. The apparatus of the present invention permits the handling of fluids to or from vessels without the limitations of long hoses and floating hoses. Also the number of hoses to and from the ship, as well as the size of these hoses, can be increased. A very important advantage is that it permits the use of the cargo manifolds of the ships and fully utilizes the ship's cargo piping, and thus can deliver a fluid to any point on the ship.

We claim:

1. Apparatus for loading and unloading a vessel at an ofishore site, comprising a fixed anchor secured on the floor of a body of water, swivel means on said anchor at the bottom of the body of water for rotation about a vertical axis through approximately 360 relative thereto, an elongate, relatively rigid, substantially straight tubular swing arm connected at one end to said swivel means at the bottom of the body of water for rotation therewith adjacent the floor of said body of water, said swing arm also pivotally connected at said one end thereof to said swivel means for pivotal movement relative to said swivel means in a substantially vertical plane, said swing arm extending a substantial distance generally horizontally over the floor of the body of water to its extreme other end and having a neutral or nearly neutral buoyancy, a hollow flexible conduit connected at one end to the extreme other end of said swing arm, means on the other end of said flexible conduit for securing said conduit to a connection on said vessel, said flexible conduit extending from said swing arm generally vertically to said vessel when said flexible conduit is secured to said connection on said vessel.

2. Apparatus for loading and unloading a vessel at an oflshore site as in claim 1, wherein a drag weight is attached to said swing arm at the other end thereof to maintain said swing arm in a generally horizontal position.

3. Apparatus for loading and unloading a vessel at an offshore site as in claim 2, wherein said one end of said swing arm is connected to said swivel means on said anchor by means of a yoke connection on said swing arm for enabling said pivotal movement of said swing arm in a generally vertical plane, said swing arm comprising a central, fluid conveying conduit, at least one pipe extending parallel to and adjacent said fluid conveying conduit and filled with a buoyant materia1, and a casing surrounding said fluid conveying conduit and said pipe.

4. Apparatus for loading and unloading a vessel at an offshore site as in claim 3, wherein said flexible conduit comprises a flexible hose connected at one end thereof to said other end of said swing arm adjacent the floor of the body of water and connected at its other end to buoy means on the surface of said body of water, said hose comprising a first hose 7 portion connected to the other end of the swing arm and having a positive buoyancy, and a second hose portion extending from said first hose portion to said buoy means on the surface of said body of water and having a negative buoyancy, the length of said flexible hose and the buoyancy of said first and second portions thereof being such that when not in use, the hose assumes the shape of a submerged S-shaped loop.

5. Apparatus for loading and unloading a vessel at an offshore site as in claim 4, wherein the space surrounding said pipe and fluid conveying conduit in said casingis filled with a buoyant foam material.

6. Apparatus for loading and unloading a vessel at an offshore site as in claim 5, wherein a flexible anchor line extends from the swivel means to the surface of said body of water, said anchor line being connected to a mooring buoy at

Claims

1. Apparatus for loading and unloading a vessel at an offshore site, comprising a fixed anchor secured on the floor of a body of water, swivel means on said anchor at the bottom of the body of water for rotation about a vertical axis through approximately 360* relative thereto, an elongate, relatively rigid, substantially straight tubular swing arm connected at one end to said swivel means at the bottom of the body of water for rotation therewith adjacent the floor of said body of water, said swing arm also pivotally connected at said one end thereof to said swivel means for pivotal movement relative to said swivel means in a substantially vertical plane, said swing arm extending a substantial distance generally horizontally over the floor of the body of water to its extreme other end and having a neutral or nearly neutral buoyancy, a hollow flexible conduit connected at one end to the extreme other end of said swing arm, means on the other end of said flexible conduit for securing said conduit to a connection on said vessel, said flexible conduit extending from said swing arm generally vertically to said vessel when said flexible conduit is secured to said connection on said vessel.

2. Apparatus for loading and unloading a vessel at an offshore site as in claim 1, wherein a drag weight is attached to said swing arm at the other end thereof to maintain said swing arm in a generally horizontal position.

3. Apparatus for loading and unloading a vessel at an offshore site as in claim 2, wherein said one end of said swing arm is connected to said swivel means on said anchor by means of a yoke connection on said swing arm for enabling said pivotal movement of said swing arm in a generally vertical plane, said swing arm comprising a central, fluid conveying conduit, at least one pipe extending parallel to and adjacent said fluid conveying conduit and filled with a buoyant material, and a casing surrounding said fluid conveying conduit and said pipe.

4. Apparatus for loading and unloading a vessel at an offshore site as in claim 3, wherein said flexible conduit comprises a flexible hose connected at one end thereof to said other end of said swing arm adjacent the floor of the body of water and connected at its other end to buoy means on the surface of said body of water, said hose comprising a first hose portion connected to the other end of the swing arm and having a positive buoyancy, and a second hose portion extending from said first hose portion to said buoy means on the surface of said body of water and having a negative buoyancy, the length of said flexible hose and the buoyancy of said first and second portions thereof being such that when not in use, the hose assumes the shape of a submerged S-shaped loop.

5. Apparatus for loading and unloading a vessel at an offshore site as in claim 4, wherein the space surrounding said pipe and fluid conveying conduit in said casing is filled with a buoyant foam material.

6. Apparatus for loading and unloading a vessel at an offshore site as in claim 5, wherein a flexible anchor line extends from the swivel means to the surface of said body of water, said anchor line being connected to a mooring buoy at the surface of the body of water for mooring a vessel thereto.