GB2494049A

GB2494049A - Wheeled beam trawl

Info

Publication number: GB2494049A
Application number: GB1215008.2A
Authority: GB
Inventors: Joel Petrus Snauwaert
Original assignee: bvba SNAUWAERT JOEL
Current assignee: bvba SNAUWAERT JOEL
Priority date: 2011-08-26
Filing date: 2012-08-23
Publication date: 2013-02-27
Anticipated expiration: 2032-08-23
Also published as: GB201215008D0; GB2494049B; FR2982123A1; BE1020206A5; NL1039771C2

Abstract

A beam trawl 1 comprises a beam 2 having spacer elements 4, 5 for maintaining the beam at a particular distance from the seafloor whilst being towed, the spacers being in the form of wheels 5 provided at the ends of the beam and a wheel 4 provided in the centre of the beam. Preferably the beam 2 is v-shaped, comprising diverging arms 2a, 2b defining an angle Î± of 160-180Â° at the centre of the beam. The centre wheel 4 is preferably mounted on a cross piece 3 extending forwardly of the beam 2 in the towing direction. The wheels 4, 5 preferably have the same diameter, and the beam preferably has a pointed leading edge when viewed in profile. The end wheels 5 are preferably rotatably attached to shafts 8 mounted on vertical plates 7 provided at the ends of the beam, with the axes of the shafts 8 being disposed beneath the axis of the beam. The wheeled beam is intended to reduce contact between the beam and the seafloor in order to reduce damage to the seafloor, and to reduce towing resistance which reduces fuel required to tow the beam.

Description

BEAM TRAWL

The present invention relates to a beam trawl, comprising a beam having one or more wing profiles, comprising pulling means for pulling the beam trawl across a seafloor, S in which the beam extends substantially horizontally and at right angles to the pulling direction during pulling, and comprising spacing elements for keeping the beam at a certain distance from the seafloor when pulling the beam trawl.

Beam trawling is a method of fishing in which a fishing cutter pulls drag nets across the seafloor using beam trawls. A beam trawl of this type consists of such a drag net which is held open by a beam. In addition, tickler chains or chain mats arc usually provided in order to startle fish on the seafloor and to thus be able to catch them in the net.

Beam trawling has several drawbacks. As a result of the fact that heavy beam trawls are pulled across the seafloor, beam trawling requires a lot of power and thus a lot of energy. In addition, these beam trawls plough up the seafloor, resulting in organisms on the bottom being startled by the tackle, becoming caught in the net and being killed.

In order to save energy, beam trawls have already been developed which are fitted with shoes comprising roller discs at the ends of the beam instead of the sliding shoes used in conventional beam trawls. Although this results in some energy savings, it leaves the problem of the beam trawl touching the seafloor unaddrcsscd.

Now, NL 1 032 044 C discloses a beam trawl which both saves energy and significantly reduces contact with the seabed. In order to contact the seabed less, said beam trawl comprises a sensor by means of which the position of the wings of the beam is controlled. By controlling the position of the wings, the beam is sucked upwards by the flow of water around the wing in the case of protruding obstacles on the seabed, so that the beam always remains at virtually the same distance from the seafloor. As a result of the beam remaining at a distance from the seafloor, there is less contact with the latter and less energy is required to pull the beam trawl.

However, in practice, NL 1 032 044 C only operates effectively when tickler chains are being used and not when chain mats arc used. At locations in which a seafloor S contains an excessive number of rocks, tickler chains are usually replaced by chain mats, by means of which the rocks can be kept out of the drag nets. The solution from NL 1 032 044 C can therefore also only be used in locations where the seabed is sandy and not in locations where thc seafloor contains many rocks. Therefore, this can only mainly be used to catch flatfish, such as for example sole, plaice, etc. It is therefore also an object of the present invention to provide an alternative solution for a beam trawl by means of which friel savings and reduced contact with the seabed compared to the conventional beam trawls can be achieved, in which said solution can also be used in locations where rocks are present on the seafloor, so that it is also possible to catch round fish, such as for example cod, in addition to flatfish.

This object is achieved by providing a beam trawl comprising a beam having one or more wing profiles, comprising pulling means for pulling the beam trawl across a seafloor, in which the beam extends substantially horizontally and at right angles to the pulling direction during pulling, and comprising spacing elements for keeping the beam at a certain distance from the seafloor when pulling the beam trawl in which the beam trawl comprises at least one outer wheel on each end of the beam and at least one centre wheel which is arranged centrally on the beam as spacing elements.

As a result of the wheels, the fishing tackle rolls across the seafloor. Due to the fact that the wheels keep the beam at a distance from the seafloor, the latter does not come into contact with the seafloor and always stays in the water. In this way, the beam can be moved with less resistance and therefore using less energy (reduced fuel consumption).

The wing profiles reinforce this effect due to the fact that, as a resuli of said wing profiles, the beam can be pulled through the water in a more streamlined manner.

Such a wing profile may be designed to have a cross section similar to the wings of, for example, an aeroplane. Characteristic of wing profiles is the fact that, in cross S section, the inflow side virtually ends in a tip, so that the profile cuts through the water, as it were, with a limited degree of displacement of water.

Due to the fact that the bcam is kept at a ccrtain distance above the scafloor, it can no longer touch the seafloor either, so that the environmental impact is significantly reduced.

The chain mat does not come into direct contact with the seafloor either. The chain mat stops rocks which could end up in the net. This solution therefore also applies both above sandy seabeds and above seabeds containing large numbers of rocks.

The solution is already successful when one outer wheel is attached to each end of the beam and one centre wheel in the centre of the beam. Depending on the dimensions of the beam and/or the dimensions and materials of the components from which the fishing tackle is made, it is also possible to provide scvcral outer wheels at cach end and scvcral ccntre wheels in the ccntrc. Preferably, however, the number is limited so that the fishing tackle is as streamlined as possible in order thus to limit the frictional resistance (and therefore the fuel consumption) and the impact on the seafloor (seabed contact) as much as possible.

Preferably, said centre wheel of a beam trawl according to the present invention, viewed in the pulling direction of the beam trawl, is arranged at least partly in front of said outer wheels.

As a result of the centre wheel being arranged in front of said outer wheels, viewed in the pulling direction of the beam trawl, the position of the beam is always corrected in time when the fishing tackle encounters obstacles on the seafloor, so that these obstacles on the seabed can be overcome without any problem, with the beam always remaining at a certain distance above the seafloor.

The beam of a beam trawl according to the prcsent invention is preferably of a substantially V-shaped design.

Such a V shape limits water displacement and thus further reduces the amount of contact with thc seabed.

In this ease, the legs of the V shape preferably extend substantially between said centre wheel and said respective outer wheel.

The legs of the V shape thrthermore preferably extend at an angle with respect to one another which is greater than 1600 and smaller than 1800. Still more preferably, said angle is greater than 170°.

A particular embodiment of a beam trawl according to the present invention comprises a cross piece which extends on the beam substantially according to the pulling direction of the beam trawl. Said centre wheel is then preferably rotatably attached to said cross piece.

A beam trawl according to the present invention furthermore preferably comprises a chain mat, so that it can also be used on seafloors which are covered with large numbers of rocks. However, the principle of the invention is also practicable using tickler chains, but in this case such a beam trawl with tickler chains can only be used above sandy seabeds.

Tn a specific embodiment of a beam trawl according to the present invention, the outer wheels are rotatably attached to shafts on web plates at the respective ends of the beam, in which the beam extends substantially between and at least partly next to the outer wheels, in which the beam is positioned above said shafts and in which the height of the beam (i.e. the dimension of the beam itself, viewed in the vertical direction from the seafloor) is smaller than the radius of the outer wheels.

Preferably, said outer wheels of a beam trawl according to the present invention have virtually the same diameter. Still more preferably, the centre wheel also has the same diameter as the outer wheels.

Most preferably, the beam of a beam trawl according to the present invention is configured as one single wing profile in order to keep the entire beam trawl as streamlined as possible.

The present invention will now be explained with reference to the following detailed description of a preferred embodiment of a beam trawl according to the present invention. This description is solely intended to give illustrative examples and to indicate further advantages and features of said beam trawl and can therefore not be interpreted as a limitation of the area of application of the invention or of the patent rights defined in the claims.

In this detailed description, reference numerals are used to refer to the attached drawings, in which: -Fig. I diagrammatically shows a beam trawl according to the present invention in side view; -Fig. 2 diagrammatically shows a beam trawl according to the present invention in front view; -Fig. 3 diagrammatically shows a beam trawl according to the present invention in top view.

The embodiment of a beam trawl () according to the present invention as illustrated in the figures comprises a V-shaped wing profile (2) such as beam (2). The legs (2a, 2b) of the V-shaped wing profile (2a, 2b) in this case extend at an angle (a) with respect to one another which is greater than 1600 and smaller than 180° and is preferably also greater than 1700. Such a V-shaped wing profile (2) ensures a very limited water displacement. The illustrated wing profile (2) has a virtually trapezium-shaped cross section. Other cross sections are conceivable as long as the inflow side, in cross section, ends virtually in a tip, so that the profile cuts through the water, as it were, with a limited degree of displacement of water.

Analogously to existing beam trawis, pulling means (6) are provided at various locations on the beam trawl (1) on which, for example, chains can engage in order to pull the beam trawl (1) across the seafloor with the aid of a fishing cutter. When pulling the bcam trawl (1), the latter cxtcnds substantially horizontally and at right angles to the pulling direction.

A web plate (7) is attached in each case to the ends of the wing profile (2). By means of a shaft (8), an outer wheel (5) is in each case rotatably attached to such a web plate (7). A cross piece (3) is provided centrally on the wing profile (2) and extends substantially according to the pulling direction of the beam trawl (1) on the wing profile (2) and a centre wheel (4) is rotatably attached thereto with the aid of a shaft (9). Viewed in the pulling direction of the beam trawl (1), the centre wheel (4) is in this way arranged in front of said outer wheels (5). The legs (2a, 2b) of the V-shaped wing profile (2) in this case extend substantially between said centre wheel (4) and said respective outer wheel (5).

The centre wheel (4) and the outer wheel (5) serve as spacing elements (4, 5) for keeping the wing profile (2) at a certain distance from the seafloor when the beam trawl (1) is being pulled. In this case, the wing profile (2) extends substantially between and at least partly next to the outer wheels (5), in which case the wing profile (2) is positioned above said shafts (8) by means of which the outer wheels (5) are attached to the web plates (7) and in which case the height of the wing profile (2) is smaller than the radius of the outer wheels (5). The outer wheels (5) and the centre wheel (4) have virtually the same diameter.

Analogously to existing beam trawls, the beam trawl (I) furthermore comprises a drag net (not shown) which is preferably attached to the ends on the web plates (7), by means of shoes comprising rolling discs. Furthermore, the beam trawl (1) preferably comprises a chain mat (not shown) which is also attached to the ends on the web plates (7), preferably in an analogous known manner.

S The fishing tackle comprising a beam trawl (1) according to the invention furthermore comprises, as is known, a frame chain, balls and a fishing line (hawser).

The chain mat, the drag net, the frame chain, the balls, the fishing line (hawser) are in this case preferably arranged with respect to one another in such a manner that the pulling power on the beam trawl is distributed at the correct position, so that the fishing gear and the beam trawl pass across the seabed smoothly and with little resistance, so that fuel consumption is reduced and less damage is inflicted on the seafloor.

Claims

<claim-text>CLAIMS1. Beam trawl (1), comprising a beam (2) having one or more wing profiles (2a, 2b), comprising pulling means (6) for pulling the beam trawl (1) across a seafloor, in which the beam (2) extends substantially horizontally and at right angles to the pulling direction during pulling, and comprising spacing elements (4, 5) for keeping the beam (2) at a certain distance from the seafloor when pulling the beam trawl (1), characterized in that the beam trawl (1) comprises at least one outer wheel (5) on each end of the beam (2) and at least one centre wheel (4) which is arranged centrally on the beam (2) as spacing elements (4, 5).</claim-text> <claim-text>2. Beam trawl (1) according to Claim 1, characterized in that said centre wheel (4), viewed in the pulling direction of the beam trawl (1), is arranged at least partly in front of said outer wheels (5).</claim-text> <claim-text>3. Beam trawl (1) according to one of the preceding claims, characterized in that the beam (2) is of a substantially V-shaped design.</claim-text> <claim-text>4. Beam trawl (1) according to Claim 3, characterized in that the legs (2a, 2b) of the V shape extend substantially between said centre wheel (4) and said respective outer wheel (5).</claim-text> <claim-text>5. Beam trawl (1) according to Claim 3 or 4, characterized in that the legs (2a, 2b) of the V shape extend at an angle (ci) with respect to one another which is greater than 1 600 and smaller than 1 80°.</claim-text> <claim-text>6. Beam trawl (I) according to one of the preceding claims, characterized in that the beam trawl (1) comprises a cross piece (3) which extends on the beam (2) substantially according to the pulling direction of the beam trawl (I).</claim-text> <claim-text>7. Beam trawl (1) according to Claim 6, characterized in that said centre wheel (4) is rotatably attached to the cross piece (3).</claim-text> <claim-text>8. Beam trawl (1) according to one of the preceding claims, characterized in that it comprises a chain mat.</claim-text> <claim-text>9. Beam trawl (1) according to one of the preceding claims, characterized in that the outer whccls (5) are rotatably attached to shafts (8) on web plates (7) at the respective ends of the beam (2), in that the beam (2) extends substantially between and at least partly next to the outer wheels (5), in that the beam (2) is positioned above said shafts (8) and in that the height of the beam (2) is smaller than the radius of the outer wheels (5).</claim-text> <claim-text>10. Beam trawl (1) according to one of the preceding claims, characterized in that said centre wheel (4) and said outer wheels (5) have virtually the same diameter.</claim-text> <claim-text>11. Beam trawl (1) according to one of the preceding claims, characterized in that the beam (2) is configured as one single wing profile (2).</claim-text>