Ocean-based device for loading and unloading of ships

Abstract

A device for loading or unloading a ship (6), wherein a loading pipe or a loading hose (12) is connected to the ship (6) via a floating, self-motored coupling unit (1) designed to be moored to the ship (6), preferably near the loading manifold (18) of the ship (6). The coupling unit (1) has sufficient propulsive capacity to maintain the ship's (6) position during the loading operation.

Description

This invention regards a device for loading and unloading of ships. More particularly, it concerns a floating coupling unit connected to an installation for delivery or receipt of cargo, and which is designed to connect to a ship, preferably at the loading manifold of the ship.

Loading of ships in the open sea is one of the more complex and risky operations in the field of transport technology. The main reason for this is that the ship to be loaded is often located relatively close to other floating or fixed installations. Over time, technical solutions for loading have been developed which simplify loading operations in the open sea considerably, and which also allow loading to take place under relatively difficult weather conditions.

Thus it is known to provide a ship with a so-called Bow Loading System (BLS), preferably at the bow section of the ship, wherein the ship is both moored and connected to a loading pipe. When moored in this fashion, the ship may turn with the wind. This method assumes that the ship is adapted for this loading solution.

With other known methods of loading and unloading at sea the ship is connected to another vessel or to a moored buoy by means of a mooring. One or more tug boats are often required to keep the ship at the correct orientation and distance with respect to the mooring object. A loading hose, generally of the type that floats in the sea, must then be retrieved, hoisted up onto the ship and connected to the ship's loading manifold. This method is complicated and can hardly be carried out under bad weather conditions.

The object of the invention is to remedy the disadvantages of prior art.

The object is achieved in accordance with the invention, by the characteristics given in the description below and in the accompanying drawings.

A free-floating coupling unit is connected to an installation for delivery or receipt of cargo via a pipe or hose connection. The coupling unit is provided with a propulsion machinery and is arranged to be able to connect to a ship, preferably at the ship's loading manifold, in a manner that is known per se, e.g. through use of buoyancy, suction cups, magnets or similar.

The propulsion machinery of the coupling unit has sufficient pushing power to maintain a ship connected to a mooring point, in the correct position. It may be sufficient to utilize the ship's bow thrusters in addition to the propulsion machinery of the coupling unit in order to achieve the required positioning.

The coupling unit may be connected to several loading pipes and thereby arranged to load different cargoes at the same time. The loading pipes are led up to the deck section of the ship, where they are connected to the loading manifold of the ship. Advantageously, as is possible by use of the invention, hoses having special couplings such as gas couplings, can be fed to the loading manifold in a controlled manner.

The power to operate the propulsion machinery of the coupling unit and any other equipment such as so called booster pumps, a recovery plant for volatile petroleum compounds, so-called VOCs, a gas cooling plant or a plant for re-gasification of liquid gas, may be supplied via a cable from the connected-up loading or unloading installation.

Advantageously the coupling unit is provided with auxiliary equipment such as a pressure surge drum. The coupling unit is suitable for remote control and may advantageously be used in an unmanned state.

As stated in the above description, the coupling unit may be used to load ordinary ships using the ship's ordinary loading manifold, without requiring any modification of the ship. Moreover, use of the device according to the invention allows loading under far more difficult weather conditions than when the loading pipe has to be retrieved from the sea.

The following describes a non-limiting example of a preferred embodiment illustrated in the accompanying drawings, in which:

FIG. 1 shows a coupling unit connected to a ship, where the ship is moored to another vessel;

FIG. 2 shows the same as FIG. 1, but here the ship is moored to a buoy anchored to the seabed; and

FIG. 3 shows the same as FIG. 1, but there the ship is maintained in position by means of the coupling unit and the ship's bow thrusters.

In the drawings, reference number 1 denotes a coupling unit comprising a hull 2 and a propulsion machinery 4. The coupling unit 1 is provided with connectors (not shown) according to techniques that are known per se, in order to allow it to be moored to a ship 6.

A hawser 8 connects the ship with a production vessel 10. A loading hose 12 runs through the sea 14 from the production vessel 10 and up to the coupling unit 1. The loading hose 12 may equally well be of the type to float on the surface of the sea 14. The loading hose continues via the hull 2 of the coupling unit 1 and up to the ship's 6 deck 16, where it may be brought up to and connected to the loading manifold 18 of the ship 6 in a conventional manner.

The propulsion machinery 4 maintains tension in the hawser 8 during the loading operation, whereby the ship 6 is kept at a safe distance from the production vessel 10. Thus there is no need to use a separate tugboat for positioning purposes during the loading operation.

In an alternative embodiment, see FIG. 2, the ship 6 is by means of the hawser 8 connected to a buoy 24 moored to the seabed 22. In this embodiment, the loading hose 12 runs from the coupling unit 1 through the sea 14 and down to a tie-in point 26 located on the seabed 22. From the tie-in point 26, a pipe 28 runs to a production vessel or a receiving installation (not shown). The embodiment is suitable for use in shallower waters.

In a further embodiment, the ship 6 is only moored to the coupling unit 1. The ship's 6 position is maintained by means of the propulsion machinery 4 and the ship's own bow thrusters 30 and/or propellers 32.

The loading hose 12 may be submerged or floating. Alternatively, it may comprise several jointed pipes.

Claims

1. A method of maintaining a ship at a desired position and orientation with respect to currents and weather conditions during loading or unloading of the ship, where use is made of a free-floating coupling unit designed to be moored to the ship, the ship being equipped with bow thrusters and the coupling unit comprising propulsion machinery; said method comprising: maneuvering the ship by utilizing the propulsion machinery of the coupling unit in co-operation with the ship's bow thrusters.

2. A method in accordance with claim 1, wherein said maneuvering step further comprises utilizing propellers of the ship.

3. A method of maintaining a ship, moored by means of a mooring line, at a desired position and orientation with respect to currents and weather conditions during loading or unloading of the ship, where use is made of a free-floating coupling unit designed to be moored to the ship, the coupling unit comprising propulsion machinery; said method comprising: utilizing the propulsion machinery of the coupling unit in co-operation with the ship's mooring line to maneuver the ship.

4. A free-floating coupling unit for use in maintaining a ship at a desired position and orientation with respect to currents and weather conditions during loading or unloading of the ship, the coupling unit comprising: a means for mooring the coupling unit to the ship; and, propulsion machinery, wherein the propulsion machinery is used to maneuver the ship.

5. The apparatus of claim 4 wherein the ship is equipped with one or more bow thrusters which work in conjunction with the propulsion machinery to maneuver the ship.

6. The apparatus of claim 4 wherein the ship is equipped with one or more propellers which work in conjunction with the propulsion machinery to maneuver the ship.

7. The apparatus of claim 4 wherein the ship is moored by means of a mooring line which is used in conjunction with the propulsion machinery to maneuver the ship.