FR2962457A1 - RIGGING OF CHALUT AND CHALUT - Google Patents

Abstract

The invention particularly relates to a trawl rig (22) which comprises a tow bar (28) and two spacers (29, 30) connected to the tow bar by articulated links.

Description

FIELD OF THE INVENTION The present invention relates to a trawl rig, and to a floating trawl having such rigging.

The invention applies to trawls for collecting floating products on the surface of a body of water, including a trawl for collecting residues including hydrocarbons floating on the surface of the sea. STATE OF THE ART A trawl is essentially made of a net, generally net reinforcing pieces such as ropes, and a rig to ensure the maneuvering of the net and the connection between the net and one or more boats towing the net. For the opening of the net of a fishing trawl at sea, rigging panels are usually used, resting on the water surrounding them when a trawler (s) tow (s) the net, and used to spread the wings of the net mutually and thus cause the opening of the net. It has been proposed in patents FR-A-2486559 and US-A-4362631, a trawl in which the dorsal surface of the net and the side strips of the ventral side of the net have a fine mesh adapted to the collection of agglomerates. hydrocarbons, while the central area of the ventral side of the net has a wider mesh facilitating the flow of water. Two vertical elements, called guindineaux, serve to keep apart the ropes, i.e. a back rope and a bead cord, which surround the opening opening of the net, to ensure a substantially constant opening of this orifice. Floats can be attached to the net and small squirrels to keep the net on the surface. Two ships are needed to tow this trawl. The net has a detachable bag which, when filled with collected products, can be separated from the net, left in the water after being tagged, and replaced with another empty bag, without taking the trawl out of the water.

Such a bag replacement can endanger men performing this replacement, especially in rough seas. The launching of a trawl, the opening of the net of a trawl, the towing of a trawl, and its landing on a ship are delicate operations, especially when the trawl is large. dimensions. A trawl for the collection of floating objects and a trawl rig with a floating / buoyant structure, i.e. a structure having positive buoyancy, are further described in EP1570131. The recovery of the products collected by floating trawls is also complex and delicate. When the mass of products collected is high, the use of a crane on board a ship may be necessary to remove the net containing the collected products from the water and to handle the net on board the vessel. Thus, the collection of products floating at sea generally requires the use of particular vessels, large tonnage, and a particularly qualified personnel. Unless explicitly stated or implied otherwise, in this application, the terms "forward", "rear", "lower", and "upper" are used by reference to an observer on the trawl and observing direction of the vessel towing the trawl. SUMMARY OF THE INVENTION An object of the invention is to provide a simple floating trawl 25 to implement. An object of the invention is to provide a trawlable trawl by a single vessel of small tonnage, and which can be used to collect floating oil on the surface of the sea. An object of the invention is to provide a trawl rig and 30 a trawl which is improved and / or which at least partially remedies the shortcomings or disadvantages of known trawl rigging and trawling.

According to one aspect of the invention, there is provided a trawl rig whose (buoyant) structure comprises a tow bar and (at least) two elements - or members - spacers connected to the tow bar by articulated links.

The invention facilitates the deployment and refolding of rigging and trawling in water, as well as the storage and handling of rigging, especially aboard a vessel of low tonnage. According to one embodiment, at least one of the articulated links, in particular each of the articulated links, comprises one (or two) link arms fixed to a spacer element and fastened to the tow bar by the intermediate of a joint. In particular, each link arm may be pivotally mounted relative to the tow bar, along a pivot axis substantially orthogonal to the longitudinal axis of the tow bar 15 and substantially parallel to the longitudinal axis of the spacer at which he is fixed. According to one embodiment, each connecting arm is pivotally mounted relative to the spacer to which it is attached, in a (second) pivot axis substantially parallel to - in particular substantially coincident with - the longitudinal axis of the retractor. The rigging preferably comprises an opening control member of a net, such as a ring, which is sliding along the tow bar. The rigging may comprise deformable filiform links - such as cables or ends - connecting the spacers to the opening control member of the net, in particular two deformable filiform links respectively connecting the longitudinal ends of the spacer concerned to the control member for opening the net, for each of the two spacers. The tow bar may comprise an abutment limiting the movement of the opening control member of the net along the tow bar, and thus limiting the spacing of the spacers apart on either side of the bar. towing, and the dimensions of the opening opening of the net. The tow bar is preferably buoyant, so that it exerts on the rig a return torque (forward) contributing to the stability of the rig partially submerged, especially when the rig is not towed. For this purpose, the bar may comprise a float secured near a first longitudinal end of the bar. According to one embodiment, the rig comprises two buoyant, elongated spacer elements, substantially identical and parallel, at least one of the two buoyant spacer elements may have asymmetrical buoyancy, the two spacer elements being hinged relative to the tow bar along respective axes of substantially parallel articulation, in particular along substantially coinciding axes. The asymmetrical / asymmetrical buoyancy of a spacer can be obtained in particular by joining a float close to only one of the two longitudinal ends of the spacer. This can also be achieved by joining two floats of different buoyancy in the vicinity of the two longitudinal ends of the spacer, equidistant from the center of gravity thereof, or by joining two buoyancy floats identical to different distances from the center of gravity of the spreader. Thus, the spacer member has a single stable position / orientation when immersed, the rig and the trawl having only a few stable floating positions, in particular two or three stable positions. These arrangements, as well as the presence of a flotation device at the end of the tow bar which is opposite the end of the bar at which the spacers are articulated, facilitate the deployment in the water rigging and by consequently the opening in the water of the net.

A third spacer element may be secured to the tow bar in the vicinity of a second longitudinal end of this bar, which extends substantially parallel to the two buoyant spacer elements.

According to one embodiment, two deformable filiform links - such as cables or ends - respectively connect the two longitudinal ends of the third retractor to the tow bar. The rig may include a member for adjusting the length of a connection by one of the deformable filiform links, such as a turnbuckle.

The tow bar may have an adjustable length. In particular, the tow bar may have a structure articulated so as to be folded, and / or may comprise portions capable of sliding mutually, so that the tow bar is telescopic.

The mass of the rig is preferably less than or around 100 kilograms, in particular of the order of about fifty kilograms. According to another aspect of the invention, there is provided a trawl which comprises a rig according to the invention and a net secured to the rigging, in particular a net secured to the rigging by removable connecting means which may comprise loops or straps s' extending around longitudinal ends of spreader elements of the rigging. According to another aspect of the invention, there is provided a trawl whose rig includes a deformable floating structure arranged to take an expanded configuration in which the structure keeps open the opening opening of the net, and a configuration picked up / folded in which the opening of the net is reduced. The rigging further comprises a deployment control device cooperating with the deformable floating structure to move this structure from the deployed configuration to the picked configuration, or vice versa.

According to one embodiment, the deformable floating structure is articulated. According to a particular embodiment, this articulated structure comprises: - a tow bar used to tow the net of the trawl, - (at least) two spacer elements used to keep open the opening opening of the net, the spacer elements being connected to the tow bar by a hinge or articulated connection; a net opening control member such as a sleeve or a ring which is slidably mounted along the tow bar, and (first) deformable filiform links - such as cables or ends - connecting each of the spacers to the opening control member of the net. According to one embodiment, the spacer elements have a cylindrical shape, a (positive) asymmetric (off-center) buoyancy, are substantially parallel, and are articulated with respect to the towing bar according to respective articulation axes which are substantially parallel , in particular substantially merged. In other words, and according to another aspect of the invention, there is provided a trawl having a net having an aperture and a rig comprising a hinged floating structure; the hinged floating structure is arranged to pass from a first configuration in which the structure keeps open the opening opening of the net, to a second configuration in which the opening of the net is smaller than in the first configuration; the rigging further comprises a net opening and closing control device, which cooperates with the articulated floating structure to move it from the first configuration to the second configuration, or vice versa. Said net opening and closing control device - and / or said deployment control device - comprises the net opening control member, as well as at least one cable or end serving to connect this organ. of control to a vessel towing the trawl. Other aspects, features, and advantages of the invention appear in the following description which refers to the appended figures and illustrates, without any limiting character, preferred embodiments of the invention. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a schematic perspective view of a floating trawl according to one embodiment of the invention.

FIG. 2 is a schematic perspective view illustrating, from another angle of view, the main components of an articulated floating rig for a floating trawl, in a configuration corresponding to the maximum opening of a net (not shown) joined together at this rig. FIG. 3 is a schematic perspective view illustrating, from another angle of view, the articulated rigging of FIG. 2, in a configuration corresponding to the "closure" of a net (not shown) secured to this rig, this configuration collected being useful for the storage of rigging and trawling, as well as for their launching. FIG. 4 is a view from above - according to IV - of the rigging illustrated in FIG. 2. FIG. 5 is a view from above - according to V - of the rigging illustrated in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION Unless otherwise explicitly or implicitly stated elements or members - structurally or functionally - identical or similar are designated by identical references in the different figures. With reference to FIG. 1 in particular, the trawl 20 comprises a net 21 integral with a rigging 22.

The net comprises a dorsal portion 210 and a ventral portion 211 which are connected by two lateral portions 212. These portions of the net form a pocket with an opening 213. Elongated floats 214 are secured to the net to increase its buoyancy. The front edges of the net which define the opening may be reinforced by ropes, such as a back rope 215 and a bead 216, in particular. These front edges are equipped with six straps 217 which provide the reversible attachment (removable) of the net 21 to the rigging 22. For this purpose, the straps 217 are attached to the spacer elements 29 to 31 of the rigging.

With reference to FIGS. 1 and 2 in particular, the rigging comprises in particular: - a tow bar 28 equipped with a stop 35; two lateral spacer elements 29, 30; a central spacer element 31; a towing cable 33 (partially shown) attached to the front end 34 of the bar 28; a float 32 secured to the bar 28 and disposed near its end 34; a ring 36 engaged around the bar 28, which is mounted freely sliding along the bar 28, between the float 32 and the stop 35; and - two cables 37 (partially shown) for the control of movement of the ring 36, which are fixed to this ring. The cables 33, 37 extend between the rigging and a vessel (not shown) towing the trawl via the cable 33. The tow bar 28 has a cylindrical shape whose longitudinal axis 23 is substantially horizontal when the rigging floats, and substantially in the extension of the cable 33 when towing the trawl. The spacer members 29 to 31 each have a cylindrical shape whose respective longitudinal axes 25 to 27 are substantially vertical when trailing the trawl.

The two lateral spacer elements 29, 30 are connected to the tow bar by articulated links, and the central spacer element 31 is fixed by its central part to the rear end 38 of the bar 28. With reference to FIGS. 5, each of the articulated links connecting the bar 28 to one of the lateral spacers 29, 30 comprises two link arms 39, 40 which are schematically represented by broken lines in FIG. 1, in order to improve the readability of this latter figure. For the same reason, two deformable filiform links 41, 42 respectively connecting the two longitudinal ends of the third spacer 31 to the tow bar 28 are not shown in FIG. 1. For the same reason, the floats of the rigging are not represented on Figures 2 to 5. Each link arm 39, 40 is attached to one of the spacer members 29, 30 by a rigid or pivotal connection, and is fixed to the tow bar by means of a hinge: each arm 39 , 40 is mounted freely pivoting on the spacer 31 secured to the bar 28, according to a pivot axis coinciding with the longitudinal axis 27 of the spacer 31.

For this purpose, in the embodiment of Figures 2 to 5, each arm has a cylindrical (tubular) extended at both ends by a plate (such as those marked 400 Figure 2) pierced with a circular hole through which extends the spacer 31. Similarly, each longitudinal end of the bar 28, in particular the end 34 illustrated in FIG. 3, which has a cylindrical (tubular) shape, is extended (terminated) by a plate 280 pierced with an orifice, the orifice 281 located at the front end of the bar 28 serving to anchor the towing cable to the bar 28. Thus, each connecting arm 39, 40 is pivotally mounted relative to the bar of towing, according to a (first) pivot axis 27 substantially orthogonal to the longitudinal axis 23 of the tow bar and substantially parallel to the longitudinal axis of the spacer 29 or 30 to which the connecting arm is attached. In addition, each connecting arm is pivotally mounted relative to the spacer 29 or 30 to which it is attached, in a (second) pivot axis substantially parallel to - in particular substantially coincident with - the longitudinal axis 25, 26 of the spacer 29 or 30 corresponding. According to an alternative embodiment, each connecting arm can be rigidly fixed to one of the spacers 29, 30.

FIGS. 2 and 3 show that the arms 39, 40 connect a central zone 312 of the central spacer 31, at the longitudinal ends of the spacers 29, 30. FIGS. 1 to 5 show that the rigging comprises, for each of the two lateral spacers 29, 30, two cables 43, 44 respectively connecting the longitudinal ends of the spacer concerned, to the ring 36 whose movement along the bar 28 is limited by the stop 35 and the float 32. As illustrated 1, each of the two lateral spacer elements 29, 30 is equipped with a float 45 so as to have a positive buoyancy and such that the center of flotation of the spacer is not confused with its center of gravity, ie to present an asymmetrical buoyancy, and thus facilitate the deployment of articulated rigging during towing. It is preferably the same with regard to the central spreader 31, so that the rigging - and the trawl have, in water, stopped, in the configuration "picked up" of the rig shown in FIGS. 3 and 5, only two stable immersed positions, thanks in addition to the float 32 equipping the bar 28: in each of these stable "lying" positions, the spacers extend along axes slightly inclined relative to the horizontal; one of the two lateral spreaders 29 or 30, which extends under the bar 28 and on which the rest of the rigging is partially at least immersed, while the other lateral spacer (30 or 29 respectively), which extends above the bar 28, is generally fully emerged. According to one embodiment, each of the spacers, link arms, and the bar 28, comprises a tubular structure of metal or plastic, which is filled with a cellular structure - with closed cells - obtained by injection of " foam "in the tubular structure. In addition, the flotation members such as those identified 32 and 45 Figure 1, may also have a rigid cellular structure.

These flotation members may be glued - or otherwise rigidly attached - to the spacers and to the bar 28. At least one flotation member secured to the central spacer may have a toric shape and be mounted freely pivoting around the spacer, so that it can be used to allow the rig to roll on the ground or on the deck of a ship when the rig is separated from the net, and arranged in the "compacted" configuration illustrated in Figures 3 and 5. In addition, the outer diameter of the integral floats of the spacers 29 to 31 may be chosen large enough so that these floats also serve to protect the hull of a vessel ("fender") when the trawl is in the water and leans against this hull. With reference to Figures 2 and 3 in particular, the two spacers 29, 30 are identical and articulated along the axis 27 relative to the tow bar, by the arms 39, 40.

The third spacer element 31 which is secured to the tow bar in the vicinity of a (second) longitudinal end 38 of this bar, extends parallel to the spacers 29, 30 side. Two cables 41, 42 respectively connect the two longitudinal ends 310, 311 of the third spacer 31 to the central part of the bar 28, in the vicinity of the stop 35.

Each of the cables or ends 41 to 44 is equipped with a tension adjustment system such as a turnbuckle, which makes it possible to tension these cables and to balance the forces transmitted by these cables. In an embodiment not shown, the tow bar is articulated and / or telescopic so as to reduce the size of the rig, especially when it is placed on board a ship. According to one embodiment, the rigging, as well as the opening opening of the net, in the deployed configuration illustrated in FIGS. 1, 2 and 4, a height - measured along an axis parallel to the axes 25 to 27 - of the order of about one meter, and a width - measured along the axis 24 - of the order of about three meters. Such rigging may have a mass of about fifty kilograms. Preferably, in this deployed configuration, the spacers - as well as the opening opening of the net - emerge over a substantial part of their height, in particular about half their height. The use of this rig with a net whose depth - measured along the axis 23 - is of the order of five meters, can collect a volume of floating products that can reach or exceed ten cubic meters. The implementation of the trawl can be carried out as follows: One or more trawls can be loaded aboard a small vessel, the rig being in its "picked up" configuration. A trawl can be manually launched by one or two operators, in this configuration of the rigging corresponding to Figures 3 and 5. The rigging of the trawl can maintain this stable configuration in the water, being partially immersed, the longitudinal axes of the spacers 29 to 31 then being slightly inclined relative to the horizontal, as long as the trawl is not towed, despite the action of the choppy or swell, under the effect of the flotation devices and their relative position. The cables 33 and 37 are kept relaxed when the ship departs from the floating trawl, until a determined distance, for example a few tens of meters, separates the trawl from the towing vessel. The unwinding of the cable 33 is then stopped and this cable is stretched and causes the towing of the trawl by means of the bar 28. The tensile forces exerted by the cable 33 at the end 34 of the bar 28 are transmitted by this bar and by the cables 41, 42 to the central spreader 31, and this spreader to the net, through the straps 217 in particular. The resistance of the water to the movement of the rigging is primarily exerted on the immersed portion of that of the two lateral spacers which extends below the bar 28, in the floating picked configuration, i.e. in the recumbent configuration. These hydrodynamic forces simultaneously cause the distance of this lateral retractor from the bar 28, and the pivoting of the rigging along the longitudinal axis of the bar 28.

At the end of this pivoting, at a pivot angle close to - and less than - 90 degrees, the lower part of the other lateral retractor which was previously emerged, also immersed. The resistance to displacement that the water then exerts on the two lateral spacers, causes the tension of the cables 43, 44 and the sliding of the ring 36 along the bar, towards the stop 35, as long as the ring is not supported on this stop. Simultaneously, the connecting arms 39, 40 pivot about the axis 27 and the lateral spacers move away from the bar 28. When the ring 36 bears against the stop 35, the extended configuration 30 of the lateral spacers is obtained, and the transverse opening of the net is maximum.

Preferably, in this configuration illustrated in FIG. 4 in particular, the value of the angle 50 formed, in the plane of this figure, by the respective axes of one of the link arms and of the bar 28, is less than 90 degrees, for example around 70 to 80 degrees.

By comparison, in the folded configuration of Figures 3 and 5, the value of this angle may be less than ten degrees. The maximum value of the angle 50 may, if necessary, be adjusted by providing a mechanism for sliding the abutment 35 along the bar 28. By modifying the position of this abutment on the bar 28 before the launching of the trawl, it is then possible to adjust the width of the trawl in its deployed configuration to a desired value, as well as the order of magnitude of the maximum drag caused by the trawl and the collected products, in order to adapt the transverse bulk of the trawl to the trawl. conditions of the collection, and / or to adapt the drag to the performance of the towing vessel. In the deployed configuration, the forces of resistance to progress exerted by the net and the collected floating products that it contains, are mainly transmitted to the bar 28 and the cable 33 by the cables 41 to 44: thanks to the proximity of the the attachment points of the straps 217 of the net and the attachment points of the cables 41 to 44, the major part of the structure of the spacers 29 to 31 is not subjected to these forces, these structures being essentially stressed in compression and in traction (axial), depending on the movements of the water and the net. Towing of the trawl for the collection of floating products 25 is generally carried out at low speed, for example at a speed of the order of 1 to 3 knots. During towing, the measurement of the tensile force exerted by the vessel on the cable 33, and / or the determination of the height of the emergent part of the net or floats of the trawl, may be used to determine the moment when the net contains a specific mass or volume of floating products.

The (approximate) determination of the emergent height of the net or the rigging is facilitated by the presence of visual flotation marks, in particular colored marks, which are provided on the floats 45 integral with the spacers, or on the upper part (emerging). spacers 29 to 31. As the collection progresses, the trawl drag increases, causing a gradual immersion of rigging and visual cues attached thereto. When the desired quantity of collected products is reached, the towing can be stopped, so that the cable 33 relaxes. The net of the trawl can then be substantially closed by exerting, on board the vessel towing the trawl, a traction on the cables 37. This traction causes the sliding of the ring 36 along the bar 28, the ring moving apart. the stop 35 and approaching the front end of the bar 28. Correspondingly, the articulated spacers 29, 30 then approach the central portion of the bar 28, closing the opening opening of the net. The trawl can then be brought closer to the ship and moored to a buoy or platform, waiting to be extracted from the water.

Alternatively, the net can be detached from the rigging, releasing spacers the rings of the straps 217, then one end attached to one of these rings / straps and sliding inside the other five rings / straps can close the net. The rig can then be hoisted on board the vessel, the net containing the collected products can then be moored to a buoy, a floating platform, or hoisted aboard a ship.

Claims (9)

CLAIMS1 - Trawl rigging (22) (20) characterized in that it comprises a tow bar (28) and two spacer elements (29, 30) connected to the tow bar by articulated links. 2 - Rigging according to claim 1 which is buoyant and has an asymmetrical buoyancy promoting its deployment under the action of hydrodynamic forces during towing. 3 - Rigging according to claim 1 or 2 wherein at least one of the articulated links - in particular each of the articulated links - comprises a connecting arm (39, 40) attached to a spacer element (29, 30) and fixed to the bar towing (28) via a hinge. 4 - Rigging according to claim 3 wherein the link arm (39, 40) is pivotally mounted relative to the tow bar, according to a pivot axis (27) substantially orthogonal to the longitudinal axis (23) of the bar towing and substantially parallel to the longitudinal axis (25, 26) of the spacer (29, 30) to which it is attached. 5 - Rigging according to claim 4 wherein the link arm (39, 40) is pivotally mounted relative to the spacer (29, 30) to which it is attached in a (second) pivot axis substantially parallel to - in particular substantially coincident with - the longitudinal axis (25, 26) of the spacer. 6 - Rigging according to any one of claims 1 to 5 which comprises an opening control member (36) of a net, such as a ring, which is sliding along the tow bar. 7 - Rigging according to claim 6 which comprises deformable filiform links (43, 44) - such as cables or ends - connecting the spacers (29, 30) to the opening control member (36) of the net. 8 - rigging according to any one of claims 6 or 7 which comprises, for each of the two spacers (29, 30), two deformablefiliformes links (43, 44) respectively connecting the longitudinal ends of the retractor considered, to the organ opening control (36) of the net. 9 - Rigging according to any one of claims 6 to 8 wherein the tow bar (28) comprises a stop (35) limiting the movement of the opening control member (36) of the net along the bar towing, and whose position along the bar (28) is preferably adjustable. - Rigging according to any one of claims 1 to 9 10 wherein the tow bar is buoyant, so that it contributes to the stability of the rig in the water. 11 - Rigging according to claim 10 which comprises a float (32) secured to the tow bar near a first longitudinal end (34) of the bar. 12 - rigging according to any one of claims 1 to 11 which comprises two buoyant members, substantially parallel and having an asymmetrical buoyancy, the two spacer elements being articulated with respect to the towing bar along axes ( 27) of substantially parallel articulation, in particular substantially merged. 13 - Rigging according to any one of claims 1 to 12 which comprises a third spacer element (31) which is secured to the tow bar (28) in the vicinity of a (second) longitudinal end (38) of this bar, and which extends substantially parallel to two buoyant lateral spacer elements (29, 30). 14 - Rigging according to claim 13 which comprises two deformable filiform links (41, 42) - such as cables or ends - respectively connecting the two longitudinal ends (310, 311) of the third spacer (31) to the tow bar (28). ). 15 - rigging according to one of claims 7, 8, or 14 which comprises a member for adjusting the length of a connection by a filiform deformable links, such as a turnbuckle.16 - Rigging according to any of Claims 1 to 15 wherein the tow bar has an adjustable length. 17 - Rigging according to claim 16 wherein the tow bar has a structure articulated so that it can be folded. 18 - Rigging according to claim 16 or 17 wherein the tow bar comprises portions capable of sliding mutually, so that the tow bar is telescopic. 19 - Rigging according to any one of claims 1 to 18 which comprises flotation marks, in particular colored markers provided on floats (45) integral spacers or on the upper part (emerging) spacers (29 to 31) . 20 - Rigging according to any one of claims 1 to 19 which has a mass less than - or close to - one hundred kilograms. 21 - Trawl (20) which comprises a rigging according to any one of claims 1 to 20 and a net (21) secured to the rigging. 22 - Trawling according to claim 21 wherein the net is secured to the rigging by removable connecting means. 23 - Trawling according to claim 22 wherein the removable connection means comprise straps (217) extending around longitudinal ends of spacer elements (29 to 31) forming part of the rig.