CA1053013A - V-shaped oil containment boom - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An oil containment boom is provided herein. It includes an elongated member of generally V-shaped cross-section, which is provided by a front wall section and a (preferably higher) rear wall section, joined together along respective lower edges. Ballast means are provided which are located at the joint between the front and rear walls for normally maintaining the elongated member upright. Float means (preferably inflatable) are provided, which are disposed between the front wall and the rear wall at a predetermined and preselected level above the joint. Liquid deflecting means are positioned above the float means and are secured to the front and rear walls in a watertight manner to form a catch basin in the upper portion of the boom, so that liquid is prevented from entering the boom below the level of the liquid deflecting means. Drainage means are provided within one of the walls, preferably the front wall to permit polluted liquid trapped in the catch basin to escape therefrom to a location outside of one of the walls.

Description

~Lo~3~3 This inven-tion rela-tes -to a novel flexible floating boom for co~taining surface contaminan~ts on bodies of L
wa-ter, and in par-ticular to an oil containment boom having the.
Eloa-ting means disposed -therewithin. I-t also relates-to a noveI
method for con-taining oil spills.
Wit`~ the trem~ndous rate of industrialization that i8 taking place throughout the world, pollutlon oE bodies of wa-ter by oll 9pills iS reaching critical proportions. Not only are ma~or oil spills occurring, such as when an oil tanker is wrecked, but also minor oil spills are a daily occurence throughout the world. Many different systems are being test-ed for removing the effects of these oil spills and one of the most successful techniques has been to contain these r spills by means of booms and then to collect the contained L
oil from the surface of the water, e.g., by skimmers. Such oil booms can be used not only for containing a major oil spill but can also be used for isolating terminals from a permanent installation, temporarily encircling tankers whichL
are being loaded and unloaded, sweeping port areas for re-moving floating patches of oil, protecting beaches, etc. In order to provide the necessary versatility, these oil booms must be inexpensive, light and easy to store and handle.
One such oil boom is in the form of a flexible fabric curtain wall which floats in the water with part of the CUL'-tain wall extending a distance below the water surface and a part extending above the water surface. Some of these flexi-ble booms are supported in the water by means of separately attached floats. Spaced vertical stiffeners are provided to maintain the boom in the necessary vertical position and they are stabilized by means of~weights along the bottom submerged ,~

, )53~9~3 edge. These booms are made up and sto~ed in convenient sec-tions, e.g. of about 100 feet in length, and when needed are :t.ached totether aDd deployed in the water to :urround and . .

.

' '.

. ~ ' .

:

. .

~; .
-la : , . , ,. . : :: .. , .,: , , .. , : : ., .
... : ~. ~ . : . . , , .:

~53~3 :
contain the oil spill.
When such booms are used in adverse sea and wind con-ditions, the~e is a tendency for then to fail because of tearing under the strain of the sea or ice conditions and also a tendency for the attached floats to be torn away, or damaged, thus allowing the boom to become submerged in cer-tain areas and consequently defeating the entire purpose of trying to totally contain the oil spill. Accordingly, there is a very great need for a flexible oil boom system which will be very inexpensive to produce, easy to handle and yet .
have sufficient strength to withstand adverse sea and wind conditions as well as to withstand any serious damage from ice floating on the surface of the water.
Canadian Patent No. 906,772 isgued August 8, 1972 to R.A. Fossberg attempted to solve such problem by providing a flexible oil boom comprising a curtain wall of sheet material having an upper portion and a lower portion. These upper and lower portions are joined together by an overlapping connec-tion at a location below the water line. At spaced locations along the length of the ~oint between the upper and lower portions are positioned flexible straps which surround the lower edge of the upper portion and pass through the over-lapping connection between the upper and lower por$ions so that the straps provide extending ends on either side of the boom. These straps are used for connecting the float mem-bers to the boom. The upper edge of the boom is preferably formed with a longitudinal pocket which contains a strength-ening rope and a similar longitudinal pocket with strength-ening rope i8 also preferably ptrovided at the bottom edge.
Vertical pockets are also provided along the boom at longi-tudinally spaced positions and these pockets contain sti~-fening members for holding the boom in a vertically upright

-2'~

.

position.
It is frequently necessary to skim oil slicks in har-bour areas. However, present skimmers encounter considerable resistance in being towed through the water and are difficult to handle. It has also become desirable to contain oil slicks resulting from underwater leaks or leaks from injured vessels.
However, the great majority of boom systems proposed for such ~;
use survive for less than a day in rough seas. In addition, many of the more rigid boom systems do not conform to the con~
tours of the waves sufficiently fast to prevent the passage of oil beneath sections which are left hanging in the air.
''"'~' "

', , ...-. ", ..
... ~, . .

~. . . .

` ~

... . . .

-2 a- ~
. .

- ,. , , ". . ,. ~. ;., os3~3 Canadian Patent No. 912,293 issued October 17~ 1972 to C.L.
Kain attempted to provide a solution to such problem by providing a flexible boom comprising at least one elongated flexible floatation unit, a flexible weighted net supported in a substantially vertical - `
position by that at least one elongated floatation unit when the boom , .
is placed in a body of water, at least one layer of flexible filtering material, that layer of flexible filtering material being associated with the weighted net to conform generally to the vertical positioning and movement of the weighted net, the layer of filtering material being -`
formed of hydrophobic, oleophilic material having a plurality of passageways therethrough permitting the flow of water through the boom while preventing the flow of liquid hydrocarbonaceous matter through the boom.
Another problem attendant in the use of such booms is that the basically heavy and bulky nature of such known booms make both the storage and handling thereof diEflcult. By the same token, notwithstan- ;
ding the weight and bulk of these retainers, such often incorporate a relatively low tensilve strength, both in the individual sections and in the joining portions, thus limiting the lengths which can be effectively used, both as a standing barrier and as a towed gathering unit.
Canadian Patent No. 912,294 issued October 17, 1972 to C.E.
Renner attempted to provide a solution to such probIem by providing such a boom comprising an elongated depending skirt having upper and lower edges9 a float section defined longitudihally along the upper edge of the skirt, a ballast section defined longitudinally along the lower edge of the skirt9 a first male joining end defined at one end of the retain-er, a second female joining end defined at the second end of the retainer, the female joining end being of a size and configuration so as telescopi- `
cally to receive the male end of an adjoining retainer3 means associated with the ends for interconnecting a pair of telescoped ends, the retain-er being formed of an elongated flexible sheet longitudinally folded to define a skirt forming pair of adjacent panels bounded along the upper

- 3 -` ` ,' .. ; ~ ~ t ~31~L3 " : .
edge by a longitudinally extending enlarged pocket constituting a por-tion of the float section, and a relatively smaller longitudinally extending pocket along the lower edges of the panel for the reception of ballast, the second pocket constituting a portion of the ballast section, means for securing the skirt defining panels together along substantially the full length thereof, float means received within the first mentioned pocket, the float means/ ballast and securing means terminating short of the second female joining end for enabling the reception of the first male joining end therein, a pair of cooperating securing collars, one collar mounted on and surrounding the float sec-tion adjaceDt each end of the retainer, the collars each having an inner edge fixed to the float section and an unsecured outer edge directed toward the corresponding end of the retainer, the collars being adapted telescopically to engage with the corresponding collars on adjacent ` -~
retainers upon an interengagement of the male and female joining ends thereon, and means associated with the collars for interconnecting a pair of telescoped collars.
Other problems are inherent in the use of such oil barriers.
The thickness of an oil slick ma~ vary from a mere fraction of an inch up to a foot or more in thickness. Therefore the barrier must extend to a sufficient depth to avoid the passing of the oil beneath the barrier; the probability of this passing of oil is increased by the action of each of waves and swells of normal sea action or as caused by passing vessels, including large cargo ships and ocean liners. However, as the depth of the barrier increases, a larger float is required, and particularly a material of substantially greater strength is required which will withstand the great force of wave and swell action as well as withstand the bombardment by miscellaneous trash-missiles, for example including objects up to the size of telephone poles. ~- -Another problem arises from the fact that many materials tend to sink or to disintegrate when they become saturated with oil or water. Oil in particular results in extensive degradation. Thus the .
: : . . , 3~3 material must remain afloat, and must be oil-resistant.
Another problem is that an oil barrier which might overcome some of the abuve and other problems would normally be highly expensive, complex, and too bulky to be of practical value in most instances.
Canadian Patent No. 914,435 issued November 14, 1972 ~o TØ
Bogosian attempted to solve such problem by providing a buoyant barrier boom comprising a substantially rigid sheet-structure comprising a first sheet of a substantially oil-resistant synthetic composition and closed-cell foam composition attached to the sheet-structure in a manner whereby that sheet-structure 10ats when placed in water in a substan-tially vertical position relative to the water~s surface and whereby about one-eighth to about two-thirds of the first sheet extends above the water surface at least about O.S foot and extends below the water's surface at least a sufficient depth to maintain the sheet in the sub-stantially vertical position, the depth being at least about one foot.
Yet another problem inherent in the use of such floating booms was that some such booms allowed oil to escape both under and over the boom when used in the open sea or in rough water due to the wave action and instability o-f the boom~
~anadian Patent No. 936,372 issued November 6, 1973 to N.P.
Cerasari purported to solve such problem by providing a floating boom comprising a plurality of connector cables, a plurality of upright support members attached to the cnnnector cables, the upright support members having a first curved end portion inwardly disposed towards the oil spill being contained or collected and a second weighted end portion, a buoyant support tube attached to the upright support member, the buoyant support tube being attached to the upright support members~ the buoyant support tube having a valve means for inflating the buoyant support tube with compressed gas from a source of such gas, and a barri-cade wall material for collecting and containing the oil attached to the upright support members~ the connector cables being adapted to be attached to at least one seagoing vessel to position the floating boom 53~L3 around an oil spill to fo~m an oil ~arricade to contain or collect the ~il spill.
Moreover, nowhere is the threat to the environment more acute than in the northern oceans where rough seas and heaYy ice conditions increase the magnitude of the problems as~oclated with controlling oil spills, and where potential damage to the environment may have lasting and severe impli-cations.
Although as described above numerous oil containment booms have been proposed, none are able to cope with condi- ~
tions encountered in ice infested, choppy water, and in areas i -where there is dominant breaking wave action by the seas ~
forming white capped waves. - -One of the problems with booms in steep choppy waves is the difficulty in making a boom respond quickly to such fast rising waves. Even if the boom follows the wave itself, it is almost impossible to make it respond to the breaking whitecap and have it buoyant enough to rise fast and high enough to keep above and catch the whitecap which is of less density, containing both water and air. Consequently, such waves have a tendency to break over normal booms, carrying oil with them.
It has been found that, in ice, a boom with external tension lines and with external floaing attachments traps ice bearing down on it and, being unable to release the pressure ~ -exerted by the drifting ice, allows forces to build up until either the boom or the mooring system breaks, thereby making the boom ineffective.
It is therefore an ob~ect of one aspect of the pre-sent invention to provide an oil containment boom which is30 able to contain the oil-impregnated white cap and spray found in breaking water, and is able to return the polluted water ~L0~3~3 from the whi-te caps to -the contained area.
It is an object of another aspect of the present invention to provide an oil containment boom having a minimum of exposed sec-tions which migh-t interfere wi-th floating ice and which minimizes a buildup of ice on -the ex-terior and `
in-terior of the boom.
lt is an object of yet ano-ther aspect of the present invention to provi.de an oil containmen-t boom which will deflect and which will, -thereby, allow passage and escape of floating ice from -the confined area but will rapidly return to its normal position for containment of oil on -the water surface in the designa-ted area. - ~ ~
It is an object of yet a further aspect of the r present invention to provide an oil con-tainment boom which can be easily stored away on a storage reel after being deflated -to a minimum.storage size.
By a broad aspect of this invention, an oil containment boom is provided comprising an elongated member f it generally V-shaped cross section including a fron-t wall sec-tion and a rear wall section joined together along respective lower edges; ballast means located at the join-t between the front and rear walls for normally maintaining said elongated member upright; float means disposed between said front wall and said rear wall at a predetermined and preselected level above said join-t; liquid deflecting means posi-tioned above said float means and secured to said front and rear walls in a watertight manner to form a catch basin in the upper portion of said boom so that li.quid is prevented from entering said boom below the ~ level of liquid deflec-ting means; and drainage means within one of said walls adapted to permi-t liquid which is trapped within -3~3 . saicl ca-tcll basin to escape -therefroln-to a ]ocat.;on outside o:f .~-one oi said walls.
By one varian-t, the liguid deflec-til~~g means comprises a collap6ible membrane.
By another variant, the liquid deflec-ting means :is cl:i.spose(l at an angle such -tha-t all -trapped liquid is caused to be drained from said catch basin.
By a further variant, the float means is a pneuma-tic -tube, and further comprislng valve means ~or inflating and deflating said pneuma-tic tube,.so -that said float is easily collapsible for convenient storage of sa:id boom.
By yet another variant, the float means is subs-tan-tially centrally positioned within said V-shaped compartment .
-to allow substantially half of said boom to be posi-tioned below -the surface of -the water. . ~ .
By a further variant, the drainage means comprises a flap valve.
By yet another variant, -the ballast means ::
comprises a lead weight sewn to the lower edges of said front 20 wall section and said rear wall section. ;
By yet a further variant, the front wall section .
is lower than said rear wall section.
By another variant, the front wall section includes a f.lexible resilient section along its top to permit inwardly directed waves to enter the inside of the boom a~ov~ said col.l.apsible membrane means.

`' '. : , ', ,. ' ~ ,: ' ' " ', .,, ' , : ' ', : - ~ , . '' ,:. .
. , ' . ~ - ' . ,' . .` ~ ` , .
.' ' ',: ,, . . ", , , ~ ,, ., :

' ' . , ' , " , ''' . , ,. ' ' :~.'' , .'., " , . ,', ' . ' ; . :' ~L~S3~3 , It will be observed -that the V-shaped boom adds another dimension -to the barrier that the whitecap must get over, Breaking whitecaps will to a large extent roll ~-s-traight over the forward wall into the V-shaped catch basin and will drain back ou-t into the contained polluted area. Spray will be caught by -the higher wall on -the downs-tream side.
Moreover, -the floata-tion material is preferably protected from con-tact with the ice. The exposed surface of the r boom is devoid oE any pro-trusions so as to cause a minimum of drag or interference wi-th external flotsom or jetsom.
In one variant, since the float means is inflatable, storage of the boom is facili-tated, s~nce the boom can be defla-ted and rolled onto a large storage reel to be r subsequently s-towed aboard a vessel, thus minimizing storage space.

t ,~.~;

g .. . . . ... .. . . . . . . . .. .
~ . . .. . .. ~.... . . .. ... . . .
.. .. . . . ~ .. . . . -.. .. .

.

~L~)S3~3 The boom is also ~esigned to be ro-tatably deflected by floating ice to allow ice to escape beyond -the confined area and -then -to be au-toma-tically returned to its ;~
normal oil spill retaining boom position, thereby providing a novel me-thod for oil containment. Thus, these booms which have -the tension in-tegral in -the ma-terial i-tself, have a tendency -to roll up on-to the ice, le-t the ice pass underneath and re-en~er the water when -the;ice has passes through or by. Although some oil will obviously be lost during this ac-tion, i-t is s-till of advantage to lose, e.g., 500 gallons of oil, but still have the boom intact and operable to trap the next e.g., 50,000 gallons of oil.
In the accompanying drawings, r Figure 1 is a transverse cross-section of the boom of an aspect of this invention;
Figure 2 is a trans~erse cross-section of the boom of an aspect of this invention in its deflated condition;
and Figures 3a, 3b, 3c, 3d and 3e are schematic cross-sectional views of a sequence of operatlons showing operation ~-in ice-infested waters.
Referring now to Figure 1, "V" shaped oil containment bason is shown indicated generally a-t 9 is shown including a front wall section 10 and a rear wall section 11 disposed about the floatation means, namely lnflatable float 13 provided with an air valve 131. ~alls 10 and 11 are disposed tangentially in relation to the float means at approximately the mid point of the height to permit the approximate lower halves of the fron-t wall section 10 and the rear wall sec-tion 11 to be positioned below the normal level 50 of the water surface.

-10~

"__ ,, .. . ., . .: .. .... .. ______ ~5;~3 The lower sec-tions of the fron-t wall 11 and -the rear wall 11.
- converge and meet at an apex 12. Disposed between and connected to walls 10 and 11 is a.lead ballast 14 for main-taining the V-shaped floating wall sections in a .
!

1 o r -lOa-_ , .. _ .. . .... . .... ... . . .. . . . .. . ... ........ .. . .. .. .

S3~ 3 basically vertical posltion while in water, with its apex 12 pointing downwardly.
The top dlverging walls 10 and 11 rise beyond the in- -flatable float 13 to a position approxlmately equal to the length of the wall sections 10 and 11 displaced below the water surface. A float harness 15 is secured at approximate-ly the ver~ical mid point of the interior f ace at longitudinal area 51 of front wall section 10 and of the interior face at longitudinal area 52 of rear wall section 11, and forms an inverse V-shaped harness adapted to straddle the inflata-ble float 13, thereby providing support for the wall sections 10 and 11. Conventional means are used to adhere the har-ness 15 to the float 13.
Positioned and secured along the entire length of front wall 10 at longitudinal area 53 is membrane 16, which is secured to the front wall at a position slightly above the float harness 15. Membrane 16 extends across float har-ness 15 to the rear wall section 11, where it ls similarly secured along the entire length of the wall, but at a point a longitudinal area 54 substantially~ higher than the point where the membrane 16 is secured to the front wall 10.
Positioned along the front wall directly above the longitudinal area 51 but below longitudinal area 53 where the membrane 16 is secured to the front wall 10 are drain holes 17 provided with flap valves 18. The flap valve l8 is of conventional type that is it functions only to allow an , outward flow of water from between walls 10 and 11 towards the outside of front wall 10. In one embodiment front wall section 10 has an inwardly curving top section forming a wave catch 101 exten-ding along the entire length of the front wall section 10, thereby making the front wall 10 sub-stantially lower than the rear wall 11 while at the same ~ime .. . .
. , : . . ., , . : ~, . . .
,.
.. : :. , :~

~C~S3~)~L3 subs-tantially preventing escape of turbulen-t water over the wall 10. The upper portion of rear wall 13 above longitudinal area 54 provides a higher wave catch 132.
As a result of the above construction, the V-shaped oil containment boom 9 is set up to perform certain desirable functions. In its ~rmal set up as shown in Figure 1, the boom is used primarily in areas where there are rough seas,.
arld where breaking waves 55 and whi-te-capped waves 56 are common, such as, for example, near shore or o-ther shallow areas and where a breaking wave 55 contains oil par-ticles sus-pended in the foam and spray part of the wave. By one aspect of this invention, the "V" shaped oil con-tainmen-t boom 9 is able to collect the oil suspended in the spray and return it to the confined area with a minimum of interference with any of the par-ts of the boom. Wave catch 101, being slightly lower then rear wall 11~ permi-ts the wave 55 to break over the -top curvature, -thereby trapping the whitecap 56 and spray within the V-shaped cavity or catch basln 110 formed between -the front wall 10 and the rear wall 11. The oil laden spray is restricted to cavity 110 by the impervious membrane 16, thus guiding return to the confinemen-t area at the ocean only through drain hole 17 andby means of flap valve 18. The normal water level of the polluted water is designated 57. At no time during the time that the oil is collec-ted from the whitecaps and the spray and is re-turned to -the confined area does the oil come in contact with -the inflatable float 13, the float harness 15 or the inside compartment 120 of -the lower submerged half of the V-shaped boom. Thus, it is seen that the oil and sludge is prevented from clogging up, eventually weighing down, 30 ~,: and submerging the boom -thèreby rendering i-t ineffective. Since ,. - ~ . .
in a preferred embodiment of this invention the faces of front wall 10 and rear wall 11 are poly--l2- _~
.~ .~ . . ....
., ... , ~ ... . , , ... ~ . . .. . . . . . . . .

~53~13 ~-~ vinyl-chloride coated, accumulation of oil and sludge on -the exposed surface is further minimized.
The advantages,discussed above have been based on construction features of aspects of -this invention which make -the V-shaped boom inheren-tly light weight. Therefore, storage shou].d be relatively easy. To facili-tate further -this storage operation, Figure 2 discloses an embodimen-t of the invention wherein -the inflatable floa-t 13 has been defla-ted wi-th -the use of air valve 131. Consequently, it is now possible -to converge -the -two wall sections 10 and 11, thereby making -the boom flat as a sandwich of -two walls 10 and 11 as outer layers and the deflated floa-t 13, harness l5, membrane 16 and ballast 14 therebetween. The boom is therefore easy to roll up by conventional means, for s-towage aboard a ship.
The present invention in another of its aspects is also adapted to operate as shown in Figure 3, namely in the schematic sequences of Figures 3a, 3b, 3d and 3e. If a large floa-ting object, e.g., ice float 301 is being retained by the F
boom 9, a great deal of pressure is exerted on the various par-ts of the boom 9 and the risk of severing the boom 9 is quite grea-t.
The resulting loss of oil would then be significant. Due to the construction of aspects of this invention, the V-shaped boom 9 has the floating means, namely infla-table float 13 positioned approximately in the vertical centre. Lead ballast 14 main-tains the boom in its normal upright position, and -thus pre-vents rela-tively small particles as well as the oil from escaping from the confined area. However; if a large floa-ting object such as, for example, large sections of floa-ting ice 301 become confined and press against the boom, the sequence in Figures 3a-3e shows how -th@ boom perm~ts escape of the large ice sections with a minimum loss of oil. When encoun--13 ~
.. . . . .. ..... . _. . .

. : :

.
: , : . :: , .

~05;~L3 tering the ice, the boom is lifted above the lce by being rotated about the horizontal axis 302 of the inflatable float 13 as seen in 3a~ and 3b. Axis 302 is slightly above the le-vel of the water. Since there are no external points to in-terfere with the ice 301, the boom 9 is allowed to slip over the ice as seen in 3c Once the ice has passed, as in 3d and the boom is free to return to its normal position, as shown in Figure 3e.
Admittedly, a small amount of oil escapes from the confined area along with the ice while the V-shaped baom is temporarily elevated above the water surface. Howev~rj this amount of escaped oil is insignificant when compared to the oil that could be lost if the boom was severed completely.
This situation would be even more hazardous in rough seas, where the oil is likely quickly to disperse on shift from one area to another much more quickly.

-',' ' .

.:- ' ' ':

. ';'~' ' " ' ':

-13 a -

Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An oil containment boom comprising: an elongated member of generally V-shaped cross section including a front wall section and a rear wall section joined together along respective lower edges; ballast means located at the joint between the front and rear walls for normally maintaining said elongated member upright; float means disposed between said front wall and said rear wall at a predetermined and preselected level above said joint; liquid deflecting means positioned above said float means and secured to said front and rear walls in a watertight manner to form a catch basin in the upper portion of said boom so that liquid is prevented from entering said boom below the level of said liquid deflecting means; and drainage means within one of said walls adapted to permit liquid which is trapped within said catch basin to escape therefrom to a location outside of one of said walls.

2. The oil containment boom of claim 1, wherein said liquid deflecting means comprises a collapsible membrane.

3. The oil containment boom of claims 1 or 2, wherein said liquid deflecting means is disposed at an angle such that all trapped liquid is caused to be drained from said catch basin.

4. The oil containment boom of claims 1 or 2, wherein said float means is a pneumatic tube, and further comprising valve means for inflating and deflating said pneumatic tube, so that said float is easily collapsible for convenient storage of said boom.

5. The oil containment boom of claim 1, wherein said float means is substantially centrally positioned within said V-shaped compartment to allow substantially half of said boom to be positioned below the surface of the water.

6. The oil containment boom of claim 1, wherein said drainage means comprises a flap valve.

7. The oil containment boom of claim 1, wherein said ballast means comprises a lead weight sewn to the lower edges of said front wall section and said rear wall section.

8. The V-shaped oil containment boom of claim 1, wherein said front wall section is lower than said rear wall section.

9. The V-shaped oil containment boom of claim 1, wherein said front wall section includes a flexible resilient section along its top to permit inwardly directed waves to enter the inside of the boom above said collapsible membrane means.