GB2351947A

GB2351947A - Improvements in/or relating to oil containment booms

Info

Publication number: GB2351947A
Application number: GB0008198A
Authority: GB
Inventors: Jonathan Robert Coulthard
Original assignee: COWEN FLOWLINE
Current assignee: COWEN FLOWLINE
Priority date: 1999-07-16
Filing date: 2000-04-05
Publication date: 2001-01-17
Anticipated expiration: 2020-04-05
Also published as: GB2351947B; GB0008198D0

Abstract

An oil containment boom 4 for containing oil spills, which might occur during the transfer of oil / oil products between ship and shore or ship and ship, is disclosed comprising a semi-rigid buoyant member 15 having a skirt 16 suspended below it, hingeably secured at one end 6 to a quay 1 and with a compressible member 7 at the other. The means of deployment is to manoeuvre a pair of booms 4A,4B so that the compressible members 7 are in contact with the hull 3A of the ship 3 and secure them in position, thus forming a containment area between ship, quay and the two booms. The oil transfer pipes 8 are passed over or through this containment area so that any spills which might occur will be confined within it and can be removed without contaminating the rest of the harbour /port. The buoyant member 15 is composed of essentially parallel cords (20, Fig 7) running axially along the length and confined circumferentially to provide a semi-rigid boom. The cords are made of water-resistant buoyant material.

Description

2351947 IMPROVEMENTS IN/ OR RELATING TO OIL CONTAINMENT BOOMS

This specification relates to booms for use in containing oil spills on water and, in particular, 5 where oil, or oil products, are transferred over water and spills and / or leakages may occur.

The problems of transferring oil from land to a ship and vice versa, or between ships at sea are well known and many procedures have been developed to minimise the risk of leakages and accidental spillage. However, occasional incidents do occur and methods to contain the oil spilt have been developed. In one particular case, where ships are refuelled in port, a system of movable booms has been developed in which one end of the boom is secured to the quay, or jetty, to which the ship is moored, and the other end is secured to the ship. The means of securing to the ship may be either a mechanical or magnetic connection but, in either case, involved procedures are required for making and undoing the connection. Typically, this involves the use of a small boat to take fitters out to the side of the ship. This is a time consuming exercise which may be critical to the operation of a ship like a ferry which is in port for only a minimum length of time. It is not unknown for such inconvenient procedures to be orriitted, despite local harbour regulations. In this eventuality, an accidental spill could be a significant problem in the confines of a port.

The means of connection to the ship must take account of the fact that the vessel will rise and fall in the water due to its state of loading, e. g. loading and unloading vehicles on a car ferry, loading of fliel, stores, etc., as well as motions due to rise and fall of tides and possibly also of flow in the water, due to currents. One means of connecting the other end of the booms has been via mechanical connections, e.g. by bolting to fixtures on the hulls of ships. Such fixtures are undesirable as they create drag when at sea and are prone to marine fouling.

Magnetic means of fixing are known and do not require fixtures on the side of the ship, but the magnets must have a powerful attractive force to secure them to the hull and hold the boom against water movement. Powerful magnets cannot easily be removed from the hull, e.g. a separation screw(s) may have to be used, and, it is not unknown for such relatively heavy pieces of equipment to have been dropped into the dock during removal, requiring the services of divers to recover them. Electromagnets are another possibility, but this requires the I provision of electrical power and leads must thus be run along the boom and connections made close to a salt water environment, which presents considerable safety hazards.

There is thus a need for a boom system which can be easily deployed from quay to ship, or between ships, to create a containment area over, or through, which oils may be transferred.

According to the invention there is provided an oil containment boom comprising:- i) a sen-ti-rigid, buoyant member; ii) a curtain, suspended below said buoyant member and connected to said buoyant member by watertight means; iii) a first end, fixed and sealed to a quay and hingeable about the point of fixture; iv-) a second end provided with a compressible member able to form an essentially watertight seat with the side of a ship moored alongside said quay; and v) means to manoeuvre said boom so that said second end may be swung away from the quay to contact said ship and back again to he close to the quay; characterised in that the boom possesses sufficient rigidity to be manoeuvred into position and secured in that position with sufficient freedom to maintain its seal with the ship irrespective of minor movements of that ship relative to the quay.

According to a first variation of the apparatus of the invention, the quay may be a second ship and both first and second ends of the boom may be provided with a compressible member able to form a watertight seal with a ship.

According to a second variation of the apparatus of the invention, pairs of booms are used to create an area of contained water, over / through which oil or petroleum products may be transferred from the quay to the ship, or vice versa, or between two ships.

According to a third variation of the apparatus of the invention, provision is made at the first, fixed end for the boom to rise and fall with tidal movements of the water while maintaining the watertight seat between boom and quay.

2 According to a fourth variation of the apparatus of the invention, the second end is adapted to maintain the watertight seal while allowing for vertical and horizontal movement of the ship's hull.

According to a fifth variation of the apparatus of the invention, the boom and its constituent parts are constructed primarily of water- resistant components having densities less than that of water so that the boom floats on water and will not become saturated with water.

According to a sixth variation of the apparatus of the invention, additional buoyancy may be provided.

In a preferred example, the oil containment boom consists of a buoyant member with a curtain suspended below. The buoyant member may be composed of a bundle of suitably waterresisting fibres running together either as single parallel cords, or as twisted cords like the strands of a rope, or like a number of ropes all being secured together into a single cylindrical form, with the whole being covered by a sheath. A range of suitably water-resistant substances are known; some of these are classed as'oleophilic', i.e. oil-liking, for example, polypropylene, which has a relative density less than unity and so will float in water and does not absorb water..

Buoyancy may be further increased by the incorporation of a gas within the sheath and round, or within, the rope bundle.

Because the individual cords / ropes are secured together by circumferential means at regular intervals along its length, the bundle behaves as a single unit, possessing considerable rigidity in the axial plane. It may, however, be flexed when the cords on the concave side of the bend will be in compression and those on the convex side will be in tension. On removal of the flexing force, the bundle will become straight again. When referring to flexure of the bundle, it,will be remembered that the bundle will be floating in water so that the flexure wiD be in the plane of the surface of the water.

3 Clearly, therefore, such a boom could be deployed between a moored ship and a quay with sufficient force to cause a little flexure so that minor movements of the ship would cause either a slight increase, or decrease, in the flexure while still maintaining contact with both quay and ship. This would accommodate limited movements of the ship due to water flow or 5 the affects of loading / unloading, etc.

It will be appreciated that manoeuvring a large ship in confined waters is a precision operation but that even a well controlled vessel can contact the quay with considerable force. If the boom of the invention is between the ship and quay when this contact occurs, it is likely to suffer abrasive damage from the contact. Because the buoyant bundle consists of a large number of separate cords, limited damage to the cords on one side can be accepted as this will result in only a reduced degree of rigidity and allow the boom to continue in use until it can be replaced at a convenient opportunity. This must be contrasted with a boom design in which the resilient element(s) is at only one side of the buoyant member and could suffer complete rupture in such a ship - quay contact.

Ship - quay contacts could also result in the boom being'folded in half, i.e. folded into a'V shape rather than deformed into the normal 'C' or U' shapes. Such violent misuse would be recoverable in a boom of the type disclosed herein which could be 'straightened out' and re-used immediately afterwards. However, equivalent 'folding' of a boom incorporating, for example, a fibreglass stiffening rod, would most probably result in breakage and the boom becoming unusable.

The rigidity of the rope bundle forming the boom, may be increased by the incorporation of, for example, polypropylene tubes into the rope bundle to provide stiffening. The degree of extra stiffening may predetermined by the choice of number of tubes and wall thickness. If both ends of the tubes are sealed, the air enclosed will add to the buoyancy of the bundle. In the event of catastrophic damage, as instanced above, the boom would still be usable as it would retain the reduced rigidity provided by the cord bundle alone.

4 in many cases, for example, ferries, oil tankers, etc., ships ply regularly between particular berths and refuel or load / unload cargo. As the ships are always moored in the same place, to align with the shore facilities, environmental protection measures can be installed at the reftielling point(s). This is one sort of application for which the invention is intended. 5 In a preferred design, the first end of the boom would be fixed, via a hinge, to the quay where it would form a sea] between the waters on either side of the boom. Arrangements could be provided for tidal movement where appropriate, for example, the fixed end could be mounted in a vertical slide. At the second end of the boom, a deformable seal member would be provided to ensure water tightness against the contours of the vessel's hull. In this description, the term 'watertight' is not intended as an absolute term, for example, in the way a submariner might use the word, but as an 'effective' seal between the end of the boom and a barnacle encrusted hull so that only an insignificant passage of water might occur past the end of the boom.

Pairs of booms according to the invention would be provided so that an area of water between the ship, the quay and the booms could be isolated during refuelling operations. The refuelling pipe would then be passed from the quay, over (or possibly through) the water contained between the booms to the refuelling connection on the ship, connected and refuelling commenced. When refuelling was complete, the flexible refuelling pipe would be kely to contain residual oil, despite attempts to empty it. Thus, when the pipe is disconnected and the free end returned to the quay, there would be a considerable risk of spillage. In this eventuality, the spillage would be confined to the area of water between the containment booms and an oil absorbent cloth, or pad, e.g. Ollsorb-Ultrarm, could be placed on the water to absorb the spillage. When this had been done, the containment booms could be swung back alongside the quay, via the hinges at their first ends.

A rope(s), secured at / near the second end of the boom, is a preferred method of manoeuvring to swing it outwards from the quay to the ship and back again. During refuelling operations, these handling ropes would be secured around appropriate bollards to keep the booms in position between quay and ship so that a small level of flexing force was maintained in the boom to accommodate firnited relative motion between ship and quay.

In a preferred example, the boom would float on the surface of the water with a proportion of its height above the water level. A curtain would be deployed, suspended from the sheath and fast with the sheath to form a watertight seal. At the bottom of the curtain, weights would be provided to maintain the curtain hanging vertically downwards for a short distance. The effect of the boom above water and curtain below would contain any oil spill, as the oil would float on the water surface. The boom and curtain would be of sufficient dimensions to accommodate small waves likely in a port and maintain the integrity of the containment.

According to a seventh variation of the apparatus of the invention, the compressible member is removably attached to the second / each end of the boom.

The same principle disclosed herein is applicable to transfers between two ships. In this case, two options are possible. In the first option, the booms would be secured permanently to the supply ship and would be deployed when a second ship came alongside for fuel to be replenished. In the second option, the boom would not be attached at either end and have compressible members at both ends. Ropes would be provided at both ends to manoeuvre and secure the boom in position. As the compressible members at the end(s) of the booms are subject to erosive wear when in contact with barnacle-encrusted ships' hulls, it is advantageous if they are detachable from the booms and replaceable.

The principle of the disclosure has application in all marine transfer operations where oil and petroleum products are to be handled, e.g. loading of tankers at crude oil production buoys or quays, loading or unloading tankers in port, ship to ship transfers, etc.

For a clearer understanding of the invention and to show how it may be put into effect, reference will now be made, by way of example only, to the following drawings in which: - Figure I is a plan view of a ship alongside a quay showing a pair of booms according to the invention creating a containment zone between the ship and the quay:

Figure 2 is a plan view of the quay shown in Figure I with the two booms in the stored position; Figure 3 is a plan view of the quay of Figure I showing the means of deploying a boom-, Figure 4 is a plan view of the quay and ship of Fig. I with one boom fully deployed and secured in position by mooring ropes; 6 Figure 5 is a side elevation of the boom of the invention attached to the wall of a quay; Figure 6 is a sectional plan view of the sliding fitment of the boom against the quay; Figure 7 is a section through the boom of the invention; and Figure 8 is a diagrammatic elevation of the free end of the boom in contact with the ship. 5 In the following description, the same reference numeral is used for the same component or for different components fulfilling an identical function.

Referring to Figure 1, a ship 3 is moored against a quay I by ropes (not shown). Projections 2 10 extend from quay I to ship 3 to protect its hull 3A from damage. Projections 2 may be simple wooden floating structures or massive structures built out from quay I to facilitate mooring operations. The particular ship 3 may be a ferry plying regularly between quay I and another port or, for example, an oil tanker. In either case, fuel oil, or oil products, have to be transferred between ship and shore. In order to contain any spillage, a containment zone 9 is created between ship 3 and quay I by means of two booms 4A and 4B. The purpose of booms 4 is to enclose an area of water 9 separate from that of the rest of dock or harbour 10.

In the event of spillage, it is easier to remove the oil from a small contained area of water 9 than from the whole of the rest of the dock 10. It is quite common for just a small amount of oil to be spilt, e.g. equivalent to a bucketful when connecting / disconnecting a fuel supply line. In the past, it has been common practice to ignore such minor spills, but they can build up within the confines of a dock or harbour to produce an environmentally objectionable level of pollution.

Each boom 4 is connected to quay I by a slidable fixture 5, via hinged connection 6. At the free end of each boom 4 is a cushion arrangement 7 which makes an essentially oil and watertight seal against hull 3A of ship 3. Dashed line 8 shows the path of a fuel connection between quay I and ship 3. Path 8 is directly over the containment zone 9 so that any spillage would be directly into containment zone 9.

Figs. 2, 3 and 4 show the method of deploying booms 4. Fig. 2 shows both booms 4A and 4B secured to quay I when not in use. In Figs. 3 and 4, one boom 4A is shows being deployed by handling ropes I I and 12. Second boom 4B is not shown for purposes of clarity. Referring to 7 Fig. 3, the free end 7 of boom 4A is secured to bollard 13B on quay I via a rope I I (not shown in Fig. 2)_ To deploy boom 4A, rope I I is slackened considerably. Rope 12 is freed from its bollard 13A and used to pull boom 4A away from quay 1. This causes boom 4A to rotate in an anticlockwise direction about hinge 6. Arrow 12A indicates the pull that is exerted on rope 12 to move boom 4A through the water. As shown in Fig. 4, rope 12 is pulled 12A until free end 7 is in contact with hull 3A. Rope 12 is secured round bollard 13A with a degree of tension. This will maintain free end 7 against hull 3A, the effect of this tension is shown by the curvature in boom 4A, When rope 12 is secure, rope I I may also be loosely secured to bollard 13B so that it does not pull free end 7 away from hull 3A. Rope 12 may be secured to a bollard 14 on projection 2, if available. The purpose of this method of securing boom 4A is to allow for a degree of movement between ship 3 and quay I while maintaining the integrity of containment zone 9. It is thus essential that boom 9 is serni-rigid yet with a degree of resilience. Boom 4B is secured in a similar manner to that of boom 4A by its own handling ropes (not shown).

The arrangement provided must be able to accommodate a degree of lateral motion of ship 3 relative to quay I as well as vertical movement of the water in the dock due to tides, etc. and vertical movement of ship I as it is loaded / unloaded. Fig. 5 shows an elevation of boom 4 against quay wall 1. The fixed end of boom 4 is mounted in a slide 5 to allow for vertical movement of the water level 23 in the dock.

Fig. 6 shows a section through the sliding mechanism 5. It consists of a channel member 28, fast with quay 1. Two T-shaped sliders 29 move vertically in channel 28. The free ends of the T-shaped sliders 29 are connected respectively to the top and bottom of a cylindrical member 30. Sleeve member 31 at the end of boom 4 is located around cylinder 30. Rotational movement of sleeve 31 about cylinder 30 provides hinge 6, allowing boom 4 to hinge in the vertical plane about member 30. In a preferred design, sleeve 31 would be in rubbing contact 3 1 A with channel member 28 to maintain a watertight seal between the boom and the quay wall. To permit easy movement of sliders 29 in channel 28 and rotation of sleeve 31 about cylinder 30, the rubbing surfaces would be provided with low ffiction facings, e.g. PTFE linings, etc.

8 The rubbing contact 3 1 A between sleeve 31 and channel 28 is only one means of providing a sea] between containment zone 9 and the rest of the dock 10 and other means are known to the skilled man. It should be noted that this seal does not have to be of high integrity as it has only to resist minor currents and wind effects, 5 Fig. 7 shows a sectional view through boom 4 which consists of a buoyant member 15, a curtain (or skirt) 16 and a keel pocket 17. Buoyant member 15 is composed of a plurality of cords 20, formed into a bundle 2 1, running lengthways along the full length of boom 4. These cords would be made of material with a density less than that of water so that the whole bundle 21 floats 23. Cords 20 may all be parallel to the boom axis, or woven together as a rope or a combination of these options. Circumferential bands (not shown) are provided at regular intervals along the boom to keep the plurality of cords 20 together as a single bundle 21 so that they will behave as a semi-rigid member. A sheath 19 is placed over the cord bundle 2 1. In a typical design, cords 20 may be c. I 00mm in diameter and buoyant member 15 may be 300-350mm diameter 33.

As buoyarrt member 15 wifl normally be in water, it is desirable that cords 20 do not become waterlogged. Thus, oleophilic materials are suitable. If the bundle of cords does not possess sufficient rigidity, or buoyancy, a pipe(s) 24, with sealed ends may be incorporated into bundle 2 1. Such pipes 24 would be, of polymeric material to give a degree of rigidity and flexibility and eliminate corrosion problems.

Suspended from sheath 19 and making a watertight connection with sheath 19 is a curtain 16 formed of a suitable polymeric material and extending a short distance 33, e.g. 300-350mm, under the water. Curtain 16 is held vertically downwards by a keel consisting of ballast 22 in a pocket 17. Ballast 22 may be a chain, or equivalent, extending along the whole length of boom 4, as shown in Fig. 5.

9 At the free end of boom 4 is a cushion member 7 consisting of a buoyant section 15A (Fig. 8), a curtain section 16A and a keel section 17A, As cushion 7 will be in close contact with hull 3 A of ship 3, abrasive wear is likely to occur as ship 3 moves upwards and downwards due to changes in its loading state. Ships' hulls 3A are often covered with barnacles and other marine growth and thus present a rough surface to cushion 7. It is important that cushion 7 makes a reasonably effective seal with hull 3A but, after a period of usage, this will suffer a loss of efficiency due to the effects of erosion. Accordingly, cushion 7 may be replaceable, as shown in Fig. 8. Here, cushion 7 is secured to boom 4 via means 25, e.g. lacing through holes or press stud connections, etc.

Section 15A contains a flexible buoyant material, e.g. a polymeric foam. Curtain section 16A is provided with an angled edge 26 to accommodate curvature of hull 3A and is kept vertical by keel 17A. Attachments 27 on boom 4 or 27A on cushion 7 are provided for securing mooring ropes I I and 12.

Where booms are not fixed, cushion members 7 are provided at both ends. Manoeuvring and mooring ropes 11, 12 would be provided at both ends on attachments 27 or 27A. Such booms could be carried as deck items and put overboard when needed for ship to ship transfers or operations at remote harbours with limited facilities.

The apparatus of the invention provides a simple, easily operated system which can be worked by a single person after ship 3 has been moored. By providing just two ropes 11, 12 to manoeuvre each boom 4, operators do not have to resort to boats or heavy clamps. Because the system is convenient, quick and easy to use, it is less likely to be ignored when operators are tired or in a hurry. If it is used every time, it will be in position to catch any spills which do occur and thus make a valuable contribution to eliminating environmental pollution.

The man skilled in the art will be aware of developments of the principle all falling within the scope of the disclosure.

IP374

Claims

What we claim is:-

I An oil containment boom comprising- i) a semi-figid, buoyant member; 11) a curtain, suspended below said buoyant member and connected to said buoyant member by watertight means-, iii) a first end, fixed and sealed to a quay and hingeable about the point of fixture; iv) a second end provided with a compressible member able to form an essentially watertight seal with the side of a ship moored alongside said quay;and v) means to manoeuvre said boom so that said second end may be swung away from the quay to contact said ship and back again to he close to the quay; characterised in that the boom possesses sufficient rigidity to be manoeuvred into position and secured in that position vAth sufficient freedom to maintain its seal with the ship irrespective of minor movements of that ship relative to the quay.
2. An oil containment boom, as claimed in claim 1, wherein neither end is fixed and both ends are provided with a compressible member able to form a watertight seal with a ship or quay.
3. An oil containment boom, as claimed in claims I and 2, wherein the buoyant member is composed of cords aligned essentially parallel to each other and contained circurnferentially to provide a semi-rigid bundle.
4. An oil containment boom, as claimed in claim 3, wherein the / some cords are twisted or plaited,
5. An oil containment boom, as claimed in claims 3 or 4, wherein the cords are made of a water-resistant material having a density less than unity.
6. An oil containment boom, as claimed in claim 5, wherein reinforcing members are incorporated lengthways into the bundle,
7. An oil containment boom, as claimed in claim 6, wherein the reinforcing members are hollow tubes.
8. An oil containment boom, as claimed in claims 5 to 7, wherein a sheath is provided around the buoyant cord bundle.
9. An oil containment boom, as claimed in claim 8. wherein the curtain is attached to the 10 sheath.
10. An oil containment boom, as claimed in claim 9, wherein the curtain is deployed by means of a weight(s) provided at its lower end.
11. An oil containment boon- as claimed in any preceding claim, wherein one end is attached to a quay or ship and provided with means for the boom to rise and fall as the water level changes.
12. An oil containment boom, as claimed in claim 11, wherein the means for the boom to rise and fall is a slider in a channel.
13. An oil containment boom, as claimed in claim 12, wherein provision is made for the boom to rotate in a horizontal plane at or near the attachment to the one end.
14. An oil containment boom, as claimed in claims 11 - 13, wherein sealing means are provided between the boom and the attachment to the quay or ship.
15. An oil containment boon- as claimed in any preceding claim, wherein the free end of the boom is provided with a compressible member to seal against a quay or the hull of a ship.
16. An oil containment boorn, as claimed in claim 15, wherein the compressible member includes a water-resistant, buoyant foam.

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17. An oil containment boom, as claimed in claim 16, wherein the curtain beneath the compressible member is adapted to fit the shape of a ship's hull below the waterline.
18. An oil containment boom, as claimed in claim 17, wherein the compressible member and its curtain are removably secured to the rest of the boom.
19. An oil containment boom, as claimed in any preceding claim, which is manoeuvrable into position by mooring ropes attached at one / both ends of the boom.

20. An oil containment boom, as claimed in claim 19, which is held in position by securing the mooring ropes to an appropriate fixture.
20. An oil containment boom, as claimed in any preceding claim, wherein the booms are used in pairs to create a containment zone between a ship and the shore / quay, or between two ships, for the purposes of containing any spillages into said containment zone.
21. A method of creating an enclosed area between a quay and a ship for containing a possible oil spill by:

i) providing a pair of semi-rigid booms, each comprising a buoyant member with a curtain, suspended below and connected to said buoyani' member by watertight means; ii) fixing and sealing a first end of each boom to a quay so that it is hingeable about the point of fixture-, iii) providing a compressible member at the second end of each boom able to form an essentially watertight seal with the side of a ship moored alongside said quay; and iv) providing a means to manoeuvre said booms so that said second ends may be brought into contact with said ship and secure them in place-, characterised in that an enclosed area is created between the quay, the side of the ship and the two booms over, or through, which oil / oil products may be passed between ship and quay so that any spillage is contained within the enclosed area.

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22. An oil containment boom as described in and by the above statement with reference to the attached drawings.

IP374 I..

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