Patent Description:
An oil boom system is a system for containing or collecting oil floating on top of a water body. The oil boom system comprises a typically U-shaped or V-shaped barrier towed behind one or several vessels, wherein the oil spill is collected at the apex of the barrier. The barrier comprises a floating body and possibly also a skirt suspended into the water body below the floating body.

<CIT> describes an oil boom system for collecting oil spill on water whereby e.g. one end of an oil boom is towed from the shore of a watercourse with flowing water e.g. a river, at an angle to the water current, to a suitable position in the watercourse, using a waterborne current rudder. The current rudder is secured to one end of a line, the other end of the line is secured to an upstream point ashore, allowing the current rudder to move out into the stream and to maintain one end of the oil boom in a suitable position in the watercourse, while the other end of the oil boom is secured to a downstream point ashore, where an oil recovery device is positioned. The current rudder is fitted with a balance rudder operated by a line or a remote control from shore, allowing the current rudder and the oil boom end attached thereto, to be recovered to shore when so required.

<CIT> describes a method for applying a dispersant or other substances to a water surface. Significant for the method that a nozzle hose system is used, said system comprising a hose or a set of hoses, that the hose or set of hoses is elevated at both ends, that one end of the hose or set of hoses is based at an operation unit, and that the other end of the hose or set of hoses is connected to a paravane that is towed by or connected to the operation unit.

A paravane is commercially available under the name BoomVane® by the applicant of the above publications <CIT> and <CIT>.

<CIT> describes a paravane for floating barrier. The paravane has at least one foil with a first side, a second side, a leading end, a trailing end, a top and a bottom, wherein at least one foil is straight and at least one second foil is curved, where one side of the straight foil and the other side of the curving foil are interconnected by a number of stays, where at least one foil is connected at the top to at least a first buoyant body and that at least the one plane at the bottom is connected to at least one ballast element, and that at the second side of the straight foil there are at least one towing line and a tow eye by which there is achieved a paravane that can keep an arrangement of lines, nets, floats in a water body in a position suitable for performing the task.

<CIT> describes a paravane for floating barrier including at least one foil with a first side, a second side, a leading end, a trailing end, a top and a bottom, wherein at least one foil is straight and at least one second foil is curved, where one side of the straight foil and the other side of the curving foil are interconnected by a number of stays, where at least one foil is connected at the top to at least a first buoyant body and that at least the one plane at the bottom is connected to at least one ballast element, and that at the second side of the straight foil there are at least one towline and a tow eye by which there is achieved a paravane that can keep an arrangement of lines, nets, floats in a water body in a position suitable for performing the task.

<CIT> describes a net-extender for trolling, attached to the midway of a towing rope as well as a conventional Otter board by using a flexible net-extender. The net-extending body has a rigid member arranged at the upstream side and a flexible net-extender joined to the rigid member and arranged at the downstream side.

<CIT> describes a fishnet expander capable of improving fishnet-expanding performance, and to provide a trawl fishing including the same. The fishnet expander is such that a warpage is formed at a blade part and the efflux port of a ridge part is formed on the end opposite to an influx port in the first direction of the ridge part, thus markedly improving lifting force acting on the blade part as compared with conventional cases and securing the shape stability of the blade part in towing.

<CIT> describes another type of paravane.

The object of the present invention is to provide an improved paravane for a barrier.

The object of the present invention is also to provide a floating barrier system which may utilize the properties of the improved paravane.

A further object of the present invention is to provide a method for deploying a barrier and a paravane to a water body and to retrieve the barrier and the paravane from a water body.

In particular, the object is to provide an improved paravane for a barrier, a floating barrier system and a method for deploying or retrieving the barrier and the paravane which achieves increased efficiency, and which achieves reduced risk for personal injuries.

The present invention relates to a paravane for a barrier towed by a vessel, wherein the paravane comprises:.

In one aspect, the lower lamella has a skirt facing edge defined as the edge between the first point and the second point, wherein the skirt facing edge of the lower lamella is secured continuously or at intervals to the main skirt.

In one aspect, the one or more flexible materials comprises fabrics.

In one aspect, the floating body is an inflatable floating body. The material of the floating body may be fabrics consisting of a reinforcement weave covered on one or both sides with thermoplastics like polyurethane, polyvinyl chloride, etc. or rubber, nitrile, etc..

In one aspect, the floating body has two layers of material, one airtight inner bladder and a mechanically strong outer fabric.

In one aspect, the main skirt is made of a non-permeable material.

In one aspect, the main skirt is made of reinforcement weave covered on one or both sides with thermoplastics like polyurethane, polyvinyl chloride, etc., or rubber, nitrile etc..

In one aspect, the main skirt is made of two fabrics which are joined together. The term "joined together" here refers to joining processes such as welding, gluing, vulcanizing, or sewing etc..

In one aspect, the upper lamellae and/or the lower lamellae are at least partially made of a permeable material.

In one aspect, the upper lamellae and/or the lower lamellae are at least partially made of a perforated fabric, a net fabric or a net structure etc..

In one aspect, the stiffening plates are built into the main skirt between two layers of fabric, wherein the fabric of the main skirt around the stiffening plates are formed by joining the fabrics together.

In one aspect, the stiffening plates are fastened directly to the main skirt only on one side. In another aspect, some stiffening plates are fastened to one side and some stiffening plates are fastened to the other side of the main skirt.

In one aspect, the stiffening plates are located at a first distance from each other in a first direction.

The first distance is sufficiently long to allow folding of the main skirt.

In one aspect, the main skirt is provided with a number of first folding lines defined by the first distance between the stiffening plates.

In one aspect, the stiffening plates are located at a second distance from each other in a second direction different from the first direction.

The second distance is sufficiently long to allow folding of the main skirt.

In one aspect the respective third corners of the upper and lower lamellas are gathered in one single point.

In one aspect, the main skirt is provided with a number of second folding lines defined by the second distance between the stiffening plates.

In one aspect, the plurality of stiffening plates is arranged in a grid with rows and columns.

In one aspect, the stiffening plates are inserted into pockets in the main skirt.

In one aspect, the stiffening plates are rectangular or square. Preferably, its corners are rounded, to prevent damages to the fabric of the main skirt, the lamella and/or other parts of the paravane. Alternatively, the stiffening plates may be triangular, polygonal, circular or semi-circular. Preferably, the stiffening plates are of the same size and shape. However, they may also be of different sizes and different shapes.

In one aspect, the stiffening plates are made of <NUM> - <NUM> thick polyethylene plates.

In one aspect, the paravane comprises a rear towing interface provided in the rear end of the floating body and/or in the rear end of the main skirt.

In one aspect, the rear towing interface comprises several connection points located continuously or at intervals between the rear top part of the floating body and the rear bottom part of the main skirt.

In one aspect, the rear towing interface is connected directly to the first end of the barrier. In this way, the paravane may be considered to be integrated with the barrier.

In one aspect, the front towing interface is connectable to the vessel and to a first end of the barrier. This may be the only towing interface needed for connecting the paravane to the vessel and to the first end of the barrier.

In one aspect, the front towing interface is connectable to the vessel, while the rear towing interface is connectable to the first end of the barrier.

In one aspect, the front towing interface is connected to the vessel via the first towing line and the first end of the barrier is connected to the front towing interface via a first additional towing line. In one aspect this first additional towing line is a bridle consisting of multiple lines for proper transfer of forces to the barrier. In one aspect this bridle consists also of a fabric.

In one aspect, the front towing interface is connected to the vessel via the first towing line and a second additional towing line, while the first end of the barrier is connected to the first towing line via the first additional towing line.

In this way, the paravane will be towed at a distance from the first end of the barrier. Hence, it is achieved that turbulence caused by the paravane being towed will occur outside of the barrier, i.e. the paravane will not cause turbulence inside the barrier, which will negatively impact for example oil spill collection.

Optionally, the rear towing interface may be connected to the barrier by means of an elastic towing line. Preferably, this elastic towing line is connected to the barrier a distance from where the first additional towing line is connected. It should be noted that the elastic towing line does not contribute during towing, its only purpose is to prevent the paravane from turning into the barrier opening in the initial towing phase, during stops in the towing or during deployment. Hence, the elastic towing line is preventing a wrong starting position for the paravane.

Optionally, a utility line with or without elastic properties may be connected to front of the floating body and or to the front of the skirt. The other end of the utility line may be fastened to one or several fixed points in first towing line. It should be noted that the utility rope does not contribute during towing, its only purpose is to enable optimal position during retrieval over a dock edge or over the stern on a vessel.

In one aspect, the respective third corners of the upper, intermediate and lower lamellas are gathered in one single point.

In one aspect, the lamellas have a first or leading edge, defined as the edge between the first point and the front towing interface. In one aspect, the leading edge is curved. In one aspect, the leading edge is tensioned during the towing operation. In one aspect the leading edge is provided with a semi-stiff flotation member ensuring that the front towing interface is kept at surface level and at a distance from the floating body to ensure correct tow starting position.

In one aspect, the lamellae have a second or trailing edge, defined as the edge between the second point and the front towing interface. In one aspect, the trailing edge is curved. In one aspect, the trailing edge is tensioned during the towing operation. In one aspect, the trailing edges is reinforced by a rope, webbing etc. to transfer forces to the rear towing interface.

In one aspect, the lamellas have a substantially triangular shape, wherein the first, second and third points are forming corners of the substantially triangular shape. Alternatively, the lamellas may comprise a fourth point provided at a distance from the main skirt. Preferably, this fourth point is also connected to the front towing interface. In this case the interface between the third and fourth point and FTI may be through a bridle consisting of two or more lines.

In one aspect, the lamellae are non parallel.

In one aspect, the floating body is an elongated floating body defined with a longitudinal direction between its front end and its rear end.

In one aspect, the front end of the floating body projects a distance from the front end of the main skirt.

In one aspect, the paravane comprises an intermediate skirt connected between the floating body and the main skirt, wherein a front distance between the front end of the main skirt and the floating body is longer than a rear distance between the rear end of the main skirt and the floating body.

According to the above, the leading edge is lower than a trailing edge. Hence, the lamella will pull the paravane downwardly in the water during use, preventing the paravane from collapsing or surfacing.

Alternatively, this can be achieved by connecting the main skirt directly to the floating body while securing the first point of the lamellas to the main skirt at a point lower than the second point.

In one aspect, the longitudinal direction of the main skirt is aligned with the longitudinal direction of the floating body. The longitudinal direction of the main skirt may be substantially parallel with the longitudinal direction of the floating body.

In one aspect, the paravane comprises a skirt ballast secured to the lower end of the main skirt. In one aspect, the paravane comprises a lamella ballast secured to the lower lamella. In one aspect, the skirt ballast and the lamella ballast comprise a weight line, i.e. a line to which a number of weight elements, such as lead elements or other denser than water elements. The skirt ballast and the lamella ballast may be connected to or integrated with the skirt and lamellae respectively.

The present invention also relates to a barrier system towable by a vessel, wherein the barrier system comprises:.

wherein the first end of the barrier is either connected to the front towing interface of the paravane or to a rear towing interface of the paravane.

In one aspect, the first end of the barrier and the second end of the barrier is connectable to the same side of the vessel.

In one aspect, the barrier system comprises a boom reel from which the barrier system is reeled out from and reeled onto. In one aspect, the boom reel is located on the vessel.

In one aspect, the paravane may be reeled onto the core of the reel with the barrier reeled outside the paravane. In one aspect the paravane may be reeled radially outside of the barrier.

According to the above, it is achieved that the barrier can be towed by one vessel only while still maintaining the opening of the barrier, defined as the distance between the first end and the second end of the barrier, sufficiently large. This is achieved by the paravane being able to pull the first end sideways out from a vessel direction.

In one aspect, the barrier system comprises towing lines to provide a distance between the vessel and the paravane, and between the vessel and the barrier.

In one aspect, the barrier system comprises a drag anchor secured to an apex of the barrier.

The present invention also relates to a method for deploying a barrier from a boom reel, wherein the method comprises the following steps:.

In one aspect, the method further comprises the initial step of:.

In one aspect, the method further comprises the step of:.

Further the method comprises retrieving the barrier system from the water to the vessel in the opposite way.

According to the above, it is further achieved that the barrier can be towed outside of a turbulence area behind the vessel. This is an advantage when the barrier is used as an oil boom for collecting oil spill, wherein it is important that the oil spill is floating on top of the water body. In the turbulence area, the oil spill tends to mix with the water, and is hence more difficult to collect.

According to the above, the paravane may be reeled out from and reeled onto a boom reel together with the barrier and towing lines. Hence, the deployment and retrieval of the paravane become more efficient, as less time and less equipment are needed. Hence, the deployment and retrieval will involve less operations which may reduce risk exposure to personnel. In particular, there is no need for a paravane deployment crane for lifting the paravane from the vessel and into the water and for lifting the paravane from the water and up to the vessel. The lifting operation by means of such paravane deployment cranes represents a considerable HSE risk.

The object of the invention is to provide a paravane for a barrier where the paravane may be reeled inside the barrier on a reel which compared to known technology reduce deployment time, reduce retrieval time, reduce operation complexity, reduce risk for personnel and eliminate the need for a paravane deployment crane on the vessel.

In addition, there is no need for a separate storage area for the paravane, as the paravane is now stored on the boom reel together with the towing lines and barrier.

As a further consequence, a smaller vessel without suitable located cranes may be used for handing the barrier system.

The term "towing line" is used herein for any type of flexible line used for towing purposes, such as a rope, a wire, a chain, webbing etc..

The term "barrier" is used herein for any type of element being used to separate one element from other elements, the other elements typically being water. The barrier may be used to separate floating or semi-floating garbage from water, such a barrier may be referred to as a garbage collector. The barrier may be used to concentrate and or separate oil spill from water, such a floating barrier may be referred to as an oil boom or active oil boom. The barrier may be used to separate aquatic organisms from water, such a barrier may be referred to as a fishing net, a trawl etc. The barrier may be a floating barrier, a partially floating barrier, or a submerged barrier.

The term "paravane" is used herein for a device being able to control a first end of a barrier to be separated from a second end of the barrier when the barrier is towed by a vessel. The paravane is a non-motorized device.

The term "flexible" is herein referring to the property of being capable of bending without breaking. The term "bending without breaking" is here used relative to the outer diameter of the core of the boom reel, wherein something is considered to be flexible if it may be reeled onto and reeled out from the boom reel without breaking. The core of the boom reel is a cylindrical object having a diameter which is typically between <NUM> to <NUM>.

Embodiments of the present invention will now be described in detail with reference to the enclosed drawings, wherein:.

Initially, it is referred to <FIG>, where a barrier system <NUM> is shown. The barrier system comprises a substantially U-shaped barrier <NUM> defined with a first end 2a, a second end 2b and an apex 2c. The area between the first end 2a and the second end 2b is referred to as an opening 2O of the barrier <NUM>. The barrier <NUM> is towed by means of a first towing line 3a and a second towing line 3b connected between the respective ends 2a, 2b of the barrier and a vessel VE.

The barrier system <NUM> further comprises a paravane <NUM>, which, when the barrier system is towed by the vessel VE, is pulling the first end 2a of the barrier <NUM> away from the second end 2b of the barrier <NUM> for the purpose of maintaining the opening 2O wide.

As shown in <FIG>, a boom reel <NUM> is installed on the stern of the vessel VE.

In the present embodiment, the barrier is an oil boom for collecting oil spill on a water surface.

It should be noted that the paravane <NUM> may be connected to the first end 2a of the barrier <NUM> and/or to the first towing line 3a in various ways. This will be described further in detail below. First, the paravane <NUM> will be described in detail.

As shown in <FIG>, the paravane <NUM> comprises an inflatable elongated floating body <NUM> defined with a longitudinal direction A11 between its front end 11a and its rear end 11b. As shown in <FIG>, the front end 11a of the floating body <NUM> projects a distance D11a relative other parts of the paravane <NUM>.

The material of the floating body <NUM> may consist of two fabric layers. First an inner airtight bladder fitted with a valve. Then an outer fabric protecting the inner bladder. The fabrics used in the inner and outer bladder may be a reinforcement weave covered on one or both sides with thermoplastics like polyurethane, polyvinyl chloride, etc. or rubber, nitrile, etc. One or more valves <NUM> are provided in the floating body <NUM> for inflating/deflating the floating body <NUM>.

In the rear end 11b, the floating body <NUM> comprises a rear towing interface RTI (indicated as a dashed area in <FIG> and <FIG>). This rear towing interface will be described further in detail below.

It should be noted that in the front end 11a of the floating body <NUM>, and in the rear end 11b of the floating body <NUM>, handles indicated as 11c are shown. These handles 11c are used during manual handling of the floating body <NUM>.

The paravane <NUM> further comprises a main skirt suspended in the water below the floating body <NUM>. As shown in <FIG> and <FIG>, the water level WL is indicated by a dashed line, wherein most of the floating body <NUM> is floating above the water level WL and wherein the entire main skirt <NUM> is submerged below the water level WL.

The main skirt <NUM> is substantially rectangular, and is defined with a longitudinal direction A20 between its front end 20a and its rear end 20b.

In the present embodiment, the main skirt <NUM> is made of two layers of fabric joined together by a welding process. The fabrics used is consisting of a relatively strong reinforcement weave covered on both sides with a mixture of softened polyurethane and polyvinylchloride. The main skirt <NUM> is non-permeable.

In the present embodiment, the length of the main skirt <NUM> is <NUM> meters and height around <NUM>,<NUM> meters.

The rear end 20b of the main skirt <NUM> may also form a part of the rear towing interface RTI, either alone or together with the rear end 11b of the floating body <NUM>, as indicated by the dashed area RTI in <FIG> and <FIG>.

The paravane <NUM> further comprises a number of lamellas <NUM>, <NUM>, <NUM>. As shown in <FIG>, the paravane <NUM> comprises an upper lamella <NUM>, a lower lamella <NUM> and three intermediate lamellae <NUM> between the upper lamella <NUM> and the lower lamella <NUM>.

In the present embodiment, the lamellas <NUM>, <NUM>, <NUM> are of substantially similar size and similar shape, and they are substantially triangular, as best shown in <FIG>. Here it is shown that each lamella <NUM>, <NUM>, <NUM> have a first point or corner 31a, 32a, 32c, which is secured to the front end 20a of the main skirt <NUM>, a second point or corner 31b, 32b, 33b, which is secured to the rear end 20b of the main skirt <NUM>, and a third point or corner 31c, 32c, 33c provided at a distance from the main skirt <NUM>. As shown in <FIG>, the third corners 31c, 32c, 33c are gathered in one single point, referred to as a front towing interface FTI. By gathering the corners in one single point, the opening(s) between the lamellas (as seen from the front view in <FIG> and as seen from the rear view in <FIG>), through which the water flows during towing, has a triangular shape. In other variants, for example where there is used a bridle, the third point of corners 31c, 32c, 33c may not be one single point, but having a vertical and or horizontal distance. This front towing interface FTI is connectable to the first towing line 3a, or connectable to the first end 2a of the barrier <NUM>.

The edge of the lamellas between the first corners 31a, 32a, 33a and the second corners 31b, 32b, 33b may be referred to as skirt facing edges 31sfe, 32sfe, 33sfe. These skirt facing edges 31sfe, 32sfe, <NUM> sfe are preferably secured continuously to the main skirt <NUM>, due to the relatively large forces transferred between the lamellas and the main skirt <NUM> during towing and to prevent main skirt <NUM> from collapsing.

The edge of the lamellas between the first corner 31a, 32a, 33a and the front towing interface FTI, i.e. between the first corner 31a, 32a, 33a and the third corners 31c, 32c, 33c may be referred to as a leading edge 31le, 32le, 33le. These leading edges 31le, 32le, 33le are preferably tensioned during towing. Preferably, the leading edges 31le, 32le, 33le are curved, as indicated by the radius RA-FTI in <FIG>. This may reduce vibrations in the leading edge during towing. In addition the relatively heavy forces are more distributed when being transferred into the front 20a of the main skirt <NUM>. In addition, the upper leading edge 31le is provided with a flexible , but semi stiff flotation member ensuring that the front towing interface FTI is kept at surface level and at a distance from the floating body to ensure correct tow starting position.

The edge of the lamellas between the second corners <NUM>1b, 32b, 33b and the front towing interface FTI, i.e. between the second corners 31b, 32b, 33b and the third corners 31c, 32c, 33c may be referred to as trailing edges 31te, 32te, 33te. These trailing edges 31te, 32te, 33te are preferably tensioned during towing. Preferably, also the trailing edges 31te, 32te, 33te are curved, as indicated by the radius RB-FTI in <FIG>. This may reduce vibrations in the leading edges during towing.

The trailing edges 31te, 32te, 33te may be reinforced by a towing line, rope or webbing etc. to transfer forces between the front towing interface FTI and the rear towing interface RTI and further into barrier first end 2a.

The lamellas <NUM>, <NUM>, <NUM> are in the present embodiment made of a heavy reinforced perforated fabric. The perforated fabric has <NUM>% opening. Due to the perforations, water is allowed to flow through the lamellas during towing. This evens out pressure built up around the lamellae due to external wave action. It also evens out pressure due to standing waves set up by the paravane <NUM> itself in different towing speeds. This reduce the probability for the lamellae collapse. The perforation also allows for more water to hit the main skirt <NUM> and thereby improve the sideways drag efficiency.

The paravane <NUM> further comprises a plurality of stiffening plates <NUM> fastened to the main skirt <NUM>. The purpose of the stiffening plates <NUM> is prevent vertical collapse of the main skirt <NUM>, especially at high towing speed. Practical tests at low towing speed shows that the paravane works without stiffening plates <NUM>. However, when the towing speed is increased above a critical level, the forces acing on the main skirt <NUM> between two lamellae cause the main skirt <NUM> to collapse in vertical direction and thereby significantly reducing the area used to produce sideways drag from the paravane. At the same time, the stiffening plates <NUM> are not considerably reducing the flexibility of the main skirt <NUM>, i.e. the main skirt <NUM> may still be reeled onto and out from the boom reel <NUM> and is hence considered flexible.

In the present embodiment, the stiffening plates <NUM> are of the same rectangular shape and of the same size, with a height H25 of <NUM>, a width W25 of <NUM>. The stiffening plates <NUM> are cut from an <NUM> thick polyethylene plate. The corners and edges of the rectangular plates <NUM> are rounded, to prevent them from damaging other parts of the paravane <NUM> when reeled onto and out from the boom reel <NUM>.

It is now referred to <FIG>. Here it is shown that the stiffening plates <NUM> are arranged in four rows R25A, R25B, R25C, R25D, each row being located in the areas of the main skirt <NUM> between each of the lamellas <NUM>, <NUM>, <NUM>. As indicated in <FIG>, the four rows are substantially oriented in a direction parallel to the longitudinal direction A20 of the main skirt <NUM>. In each row, the stiffening plates <NUM> are located at a first distance D25A from each other. Between each row, the stiffening plates <NUM> are located at a second distance D25B from each other.

As illustrated schematically in <FIG>, the distances D25A, D25B allow the main skirt <NUM> to be folded <NUM>° along folding lines FLA, FLB indicated in <FIG>.

In the present embodiment, the stiffening plates <NUM> are built into the main skirt <NUM> between two layers of fabric, wherein the fabric of the main skirt <NUM> around the stiffening plates are formed by welding the fabrics together.

The paravane <NUM> further comprises an intermediate skirt <NUM> connected between the floating body <NUM> and the main skirt <NUM>. As indicated in <FIG>, there is a front distance D40a between the front end 20a of the main skirt <NUM> and the floating body <NUM> which is longer than a rear distance D40b between the rear end 20b of the main skirt <NUM> and the floating body <NUM>.

Due to the main skirt <NUM>, the leading edges 31le, 32le, 33le of the lamellas become lower than the trailing edges 31te, 32te, 33te of the respective lamellas. Hence, the lamellas <NUM>, <NUM>, <NUM> will pull the paravane <NUM> downwardly in the water during use, preventing the paravane <NUM> from collapsing or surfacing. Of course, the downwardly directed pulling force created by the orientation of the lamellas due to the intermediate skirt are adjusted to not exceed the upwardly directed force created by the buoyancy of the floating body <NUM>.

As shown in <FIG>, the longitudinal direction A20 of the main skirt <NUM> is not exactly in parallel with the longitudinal direction A11 of the floating body <NUM> due to the intermediate skirt <NUM>. Still, the longitudinal direction A20 of the main skirt <NUM> may be considered to be approximately parallel with the longitudinal direction A11 of the floating body <NUM>.

The paravane <NUM> may further comprise a skirt ballast <NUM> secured to the lower end of the main skirt <NUM> (shown in <FIG>), and the paravane <NUM> may further comprise a lamella ballast <NUM> secured to the lower lamella <NUM> (shown in <FIG>). The skirt ballast and the lamella ballast may comprise a flexible weight or lead line, i.e. a line to which a number of weight elements (lead or other denser than water elements) are connected or integrated. By connecting the weight elements spaced apart from each other, the skirt ballast and the lamella ballast are considered to be flexible.

It should be noted that the floating body <NUM>, the main skirt <NUM>, the upper lamella <NUM> and the lower lamella <NUM> are made of one or more flexible materials, making the entire paravane flexible when the floating body <NUM> is deflated. It should be noted that even though stiffening plates <NUM> are secured to the main skirt <NUM>, the paravane is considered flexible within the definition of "flexible" above.

The barrier system <NUM> and the paravane <NUM> have been described above. It is now referred to <FIG>. Here, the front towing interface FTI of the paravane <NUM> is connected to the vessel VE via the first towing line 3a, and the rear towing interface RTI of the paravane <NUM> is connected to the first end 2a of the barrier <NUM>.

An alternative embodiment is shown in <FIG>. Here, the front towing interface FTI is connected to the vessel VE via the first towing line 3a and the first end 2a of the barrier <NUM> is connected to the front towing interface FTI via a first additional towing line 3a1. Optionally, the rear towing interface RTI may be connected to the barrier <NUM> by means of an elastic towing line 3c. Preferably, this elastic towing line 3c is connected to the barrier <NUM> a distance from where the first additional towing line 3a1 is connected. It should be noted that the elastic towing line 3c does not contribute during towing, its only purpose is to prevent the paravane <NUM> from turning into the barrier opening 2O in the initial towing phase or during stops in the towing. Hence, the elastic towing line 3c is preventing a wrong starting position for the paravane <NUM>.

Yet an alternative is shown in <FIG>. This embodiment is similar to the above embodiment, the differences being that the barrier system <NUM> comprises a second additional towing line 3a2 between the first towing line 3a and the front towing interface FTI and that the first additional towing line 3a1 is connected to the first towing line 3a instead of to the front towing interface FTI.

Optionally, the additional towing line 3a2 may, also in the form of a bridle with two or more lines, be connected directly from front towing interface FTI to the first end 2a of the barrier. In this case the first towing line 3a is also connected to the first end 2a of the barrier, but not necessarily at the same point.

In <FIG> and <FIG>, the paravane <NUM> will be towed at a distance from the first end 2a of the barrier <NUM>. Hence, it is achieved that turbulence caused by the paravane <NUM> being towed will occur outside of the barrier <NUM>, i.e. the paravane <NUM> will not cause turbulence inside the barrier, which could negatively impact for example oil spill collection. Hence, it is assumed that the embodiments shown in <FIG> and <FIG> can be towed at higher speed than the embodiment of <FIG>.

In <FIG>, <FIG> and <FIG>, turbulence areas are indicated with wavy lines. The vessel turbulence is indicated as a turbulence area TA. It is shown in <FIG>, <FIG> and <FIG> that the barrier <NUM> may be towed outside of the turbulence area TA.

It is now referred to <FIG>. Here, the boom reel <NUM> is shown to comprise a boom reel core 5a with flanges 5b in each end thereof. The outer core diameter D5a is indicated in <FIG> and may be <NUM> - <NUM>.

In <FIG>, it is shown that the first towing line 3a and the second towing line 3b are reeled onto the core 5a first, i.e. the towing lines 3a, 3b are nearest the core 5a. Then, the paravane <NUM>, the first end 2a of the barrier <NUM> and the second end 2b of the barrier <NUM> are reeled onto the core, the first end 2a and the second end 2b being reeled onto the core substantially in parallel (at least when assuming that the length of the first towing line 3a is equal to the length of the second towing line 3b). Due to the flexible properties of the main skirt <NUM>, the deflated floating body <NUM> and the lamellas <NUM>, <NUM>, <NUM>, schematically indicated in <FIG> as dotted lines, are folded around stiffening plates <NUM>. Hence, the entire paravane <NUM> is considered to be flexible. It should be noted that <FIG> is a schematical illustration only, as the barrier <NUM> in practice will be tensioned more when reeled onto the core 5a, reducing the space occupied by the paravane <NUM> in <FIG> and reducing the space between layers of the barrier <NUM> outside of the paravane.

Finally, the end 2c of the barrier <NUM> is reeled onto the core 5a. As indicated in <FIG>, a drag anchor <NUM> is connected to the end 2c of the barrier <NUM>.

It should be noted that in the present embodiment of the method, the barrier <NUM> is deployed from the boom reel <NUM> on the stern of the vessel VE by means of the crew on the vessel VE only. The steps of deploying the barrier from the boom reel <NUM> will now be described.

In a first step, the drag anchor <NUM> is released to the water.

Then, vessel VE is moved slowly forward, allowing the drag anchor <NUM> to gradually pull the apex 2c of the barrier <NUM> away from the boom reel <NUM> and out into the water. For each inflation valve of the barrier <NUM>, the barrier <NUM> is inflated.

As the vessel VE moves further forward, the barrier <NUM> is reeled out from the boom reel <NUM> and inflated until the first end 2a and the second end 2b of the barrier <NUM> are deployed into the water. The paravane <NUM>, as shown in <FIG>, is already connected to the first towing line 3a and to the first end 2a of the barrier <NUM>. The elastic towing line 3c is also indicated in <FIG>. The floating body <NUM> is inflated and is also deployed into the water.

In a final step, the towing lines 3a, 3b are at least partially deployed to the water. The towing lines 3a, 3b may be secured to the boom reel <NUM> during the towing. However, they may also be released and secured to the hull of the vessel VE, as indicated in <FIG>, <FIG> and fig.

The paravane <NUM> will, as the barrier <NUM> and the paravane <NUM> are towed by the vessel VE, now pull the first end 2a away from the second end 2b and hence increase the opening 2O of the barrier. As is apparent from the description of the method above, no crane is needed.

The opposite steps are performed when retrieving the barrier and paravane from the water. Again, no crane is needed.

According to the above, it is further achieved that the barrier <NUM> can be towed outside of a turbulence area TA behind the vessel VE. This is an advantage when the barrier <NUM> is used as an oil boom for collecting oil spill, wherein it is important that the oil spill is floating on top of the water body. In the turbulence area TA, the oil spill tends to mix with the water, and is hence more difficult to collect.

Some further alternative embodiments will be described below.

In one embodiment, the skirt facing edges 31sfe, 32sfe, 33sfe of the lamellas may be secured to the main skirt <NUM> at intervals instead of continuously.

It is now referred to <FIG>. Here, it is shown that the lamellas <NUM>, <NUM>, <NUM> may comprise fourth corners or points 31d, 32d, 33d provided at a distance from the main skirt <NUM>. The fourth points 31d, 32d, 33d are also connected to the front towing interface FTI. Hence, the lamellas are no longer true triangles. In <FIG> it is also shown that the third point 31c and the fourth point 31c are connected to the first towing line 3a via a bridle (i.e. two towing lines). It is considered only a matter of definition whether the front towing interface FTI is formed by the points 31c, 31d only or if the front towing interface FTI is formed by the points 31c, 31d together with the bridle.

Similarly, the rear towing interface RTI may be connected to the barrier <NUM> by means of two or more towing lines, for example two lines connected between the barrier <NUM> and the rear end 11b of the floating body <NUM>, and two lines connected between the barrier <NUM> and the rear end 20b of the main skirt <NUM>.

It should be noted that the intermediate skirt <NUM> is not an essential feature. In an alternative embodiment, the main skirt <NUM> may be connected directly to the floating body <NUM>. The downwardly directed pulling force may still be obtained by securing the first points 31a, 32a, 33a of the respective lamellas to the main skirt <NUM> at a point lower than the second point 31b, 32b, 33b of the respective lamellas.

It should be noted that instead of using the drag anchor <NUM>, a further vessel (not shown) may be used to reel out the barrier from the boom reel <NUM>. Other means for providing drag in the barrier <NUM> may also be used.

It is now referred to <FIG>. Here it is shown that the paravane <NUM> further comprises foils <NUM> connected between the lamellas <NUM>, <NUM>, <NUM> at a distance from the main skirt <NUM>. The foils <NUM> reduces how far the lamellas can be pulled away from each other during towing. The foils <NUM> may be fitted with stiffening plates with equal properties as the stiffening plates <NUM> in the main skirt <NUM>. In this case the foils <NUM> will also establish a minimum distance between lamellas <NUM>, <NUM> and <NUM>. In <FIG>, it is shown that the foils <NUM> are oriented substantially in parallel with the main skirt <NUM>. The foils <NUM> are made of a flexible material, such as a permeable, a semipermeable or a non-permeable material.

It should be noted that some of the stiffening plates <NUM> may be slightly bent during exposure to forces on the boom reel core 5a. Tests show that this does not impact the paravane functionality negatively.

It should further be noted that the above paravane <NUM> is intended for use on a starboard side of the vessel. It should be noted that a mirrored paravane may be used on a port side of the vessel. Of course, the vessel may use one starboard type of paravane and one port side type of paravane simultaneously, to tow two separate barriers or to tow one wider barrier. It is also possible to use two paravanes <NUM> on the same side of the barrier, for example a first paravane <NUM> as shown in <FIG> (i.e. connected via the rear towing interface to the first end 2a of the barrier) and a second paravane <NUM> as shown in <FIG> or <FIG>.

The embodiments described above are focused on the use of the paravane <NUM> for an oil spill boom such as high speed Current Buster®, a garbage collecting boom etc..

However, the paravane may also be used during towing of other objects in water, for example fishing gear, such as a trawl.

Claim 1:
Paravane (<NUM>) for a barrier (<NUM>) towed by a vessel (VE), wherein the paravane (<NUM>) comprises:
- a floating body (<NUM>);
- a main skirt (<NUM>) suspended below the floating body (<NUM>), wherein the main skirt (<NUM>) is defined with a longitudinal direction (A20) between its front end (20a) and its rear end (20b);
- an upper lamella (<NUM>) having a first point (31a) secured to the front end (20a) of the main skirt (<NUM>), a second point (31b) secured to the rear end (20b) of the main skirt (<NUM>) and a third point (31c) provided at a distance from the main skirt (<NUM>);
- a lower lamella (<NUM>) having a first point (33a) secured to the front end (20a) of the main skirt (<NUM>) below the upper lamella (<NUM>), a second point (33b) secured to the rear end (20b) of the main skirt (<NUM>) below the upper lamella (<NUM>) and a third point (33c) provided at a distance from the main skirt (<NUM>);
- a front towing interface (FTI) connected to the third point (31c) of the upper lamella (<NUM>) and the third point (33c) of the lower lamella (<NUM>);
wherein the floating body (<NUM>), the main skirt (<NUM>), the upper lamella (<NUM>) and the lower lamella (<NUM>) are made of one or more flexible materials; and
wherein the upper lamella (<NUM>) has a skirt facing edge (31sfe) defined as the edge between the first point (31a) and the second point (31b), wherein the skirt facing edge (31sfe) is secured continuously or at intervals to the main skirt (<NUM>);
wherein the paravane (<NUM>) comprises at least one intermediate lamella (<NUM>) having a first point (32a) secured to the front end (20a) of the main skirt (<NUM>) between the upper lamella (<NUM>) and the lower lamella (<NUM>), a second point (32b) secured to the rear end (20b) of the main skirt (<NUM>) between the upper lamella (<NUM>) and the lower lamella (<NUM>) and a third point (33c) provided at a distance from the main skirt (<NUM>), wherein the third point (33c) is connected to the front towing interface (FTI);
characterized in that:
- the paravane (<NUM>) comprises a plurality of stiffening plates (<NUM>) fastened to the main skirt (<NUM>);
- the stiffening plates (<NUM>) have a height (H25) being lower than a height (H30) between the lamellae (<NUM>, <NUM>, <NUM>);
- the stiffening plates (<NUM>) are fastened to the main skirt (<NUM>) between the lamellae (<NUM>, <NUM>, <NUM>).