WO2005055708A1

WO2005055708A1 - Trawl driving devices, adjustment device, method and systems

Info

Publication number: WO2005055708A1
Application number: PCT/NO2004/000376
Authority: WO
Inventors: Henning Skjold-Larsen
Original assignee: Henning Skjold-Larsen
Priority date: 2003-12-09
Filing date: 2004-12-07
Publication date: 2005-06-23
Also published as: EP1696723A1; CA2548466A1; DK1696723T3; NO20035477L; ES2305895T3; DE602004012889D1; ATE390839T1; CA2548466C; EP1696723B1; NO20035477D0

Abstract

The invention relates to a drive device (10), an adjusting device with a drive device (10) and a trawl system, where an elongated adjusting element (11) is mounted round at least one turning point (12) and is connected to a drive unit (13) where the adjusting element (11) is mounted between at least one line (3) and a basic body (5) and where the drive unit (13) changes the adjusting element's (11) position relative to the basic body (5). The invention also relates to a method for controlling the opening of at least one trawl bag and a control system.

Description

Trawl driving devices, adjustment device, method and systems

The present invention relates to devices for dynamic orientation of at least one basic body and/or a trawl bag during a trawl operation, a system comprising a device, a method for dynamic orientation of the trawl bag and a control system thereof.

During a trawl operation it is essential to try to maintain as ideal a trawl geometry as possible in order to achieve optimal operation of the trawl and thereby the largest possible catch. If the trawl geometry becomes unstable or misaligned, this has a negative effect on the efficiency of the catch while at the same time leading to increased wear on seine and gear, and increasing the risk of snagging and jamming. The opening of the trawl by means of trawl doors and weights is particularly vital for maintaining a trawl geometry that is as ideal as possible. Where trawling is conducted with a plurality of trawls alongside one another, this becomes particularly important since in this case it is even more difficult to achieve stable trawl geometry, i.e. to avoid the complete or partial collapse of one or more of the trawls.

There are several types of solutions in the prior art. One of these involves devices that project outside the gunwale for keeping the trawl bags open, another is described in NO 307541 concerning a device comprising at least three trawl bags, where the trawl bags are interconnected at common points where these common points have devices which during trawling receive a static tractive force in a direction generally away from the trawl direction as a direct result of the device's physical shape, thereby holding the trawler bags open. Other examples of static systems like this are also described in WO 86/02525, GB 1142140 and US 4 045 901. The common feature of all of these solutions is that they are statically attached to the trawl lines when the trawl is in use and the elements can only be adjusted by regulating the winding in and out from a winch on the vessel. This means that the elements are attached to the trawl lines at fixed attachment points on the elements before the trawl is deployed and can only be altered when the trawl is picked up. This severely limits the ability to control the trawl opening once the trawl has been deployed.

WO 81/03475 describes a unit that can be manned or remotely controlled and is dragged under water with devices that enable the unit's position to be adjusted vertically or horizontally. The unit is based on the combination of devices for adjusting the length of various cable sections and devices for altering the unit's geometry, thereby influencing the unit's position while the unit is moved in the water. The unit is intended for underwater surveys, etc. and is not adapted to serve as a directing module for other devices. GB 2 122 562 discloses a wing-shaped unit in connection with a trawl where the unit's attachment points can be adjusted before use and where a screw device is provided for adjusting the unit's position during use. This device is highly inflexible, its freedom of movement being restricted by the screw mechanism.

The ideal trawl geometry for a trawl is dependent on a number of factors such as seabed conditions, depth, current, trawl type, towing rate, etc. Many of these parameters are not static, varying from one trawl drag to another as well as during each trawl operation. The existing solutions for maintaining the trawl geometry are essentially static with the trawl being arranged for a given situation before deployment and the only possibility of adjustment is to adjust the lines for the trawls by means of the winches on the deck of the vessel. This severely limits the possibility of adjustment.

The object of the present invention is to provide devices that enable a dynamic adjustment of the opening of the trawl to be achieved by simple means during a trawl operation. It is also an object of the present invention to provide a device for dynamic adjustment of a basic element in connection with a trawl, together with a system, method and control system for use in the method, all of which have in common the ability to provide a dynamic and more active control of elements in connection with a trawling process.

The object is achieved by means of devices, a system and method as indicated in the following independent claim, with additional features of the invention indicated in dependent claims.

The invention comprises two drive devices, an adjusting device comprising a drive device, a trawl system, a method for controlling the opening of trawls and a control system for use in the method.

The object of the drive devices according to the invention is to offer the capability of dynamic adjustment of a basic body in connection with one or more trawl bags during trawling. The trawls in question may, for example, be pelagic or bottom trawls. There may be several trawls arranged alongside or above one another.

The term dynamic adjustment refers to the ability to adjust the position of the basic body and the opening of the trawl bag during a trawl operation without having to bring up the trawl and alter the position of lines for the trawls and/or the attachment to the basic bodies. Dynamic adjustment offers the possibility of altering the trawl geometry as a result of dynamic variables that are altered during a trawl operation, or from one trawl operation to another trawl operation. Inputs for this dynamic regulation can be obtained by reading sensors placed on the vessel, the trawl, the lines or from some other source. Transmission of control signals to the drive unit may be carried out by means of acoustic signals, wirelessly by other means, or by physical connection of sensors to a control unit for the drive unit.

The term "basic body" should be understood to refer to any body that can be placed in connection with the trawl during a trawl operation in order to control and/or ensure the desired opening of the trawls. A basic body may be what in the art is called, for example, clumps, middle lumps, roller lumps, roller weights, doors, wings and combinations thereof, etc. A basic body will generally be specially designed to suit the use for which it is intended. A lump, for example, will be wide and low and of substantial weight in order to pull the trawl in the direction of the seabed, while a door is more likely to be narrow and high with the desired fluid flow pull in order to provide the desired lateral opening of the trawl bag. Thus the basic bodies may be designed in a shape specially adapted to their use. The present invention can be employed in connection with any kind of basic body and irrespective of the shape of the basic body. The type and shape of the basic body therefore form no part of the invention and will therefore only be referred to in entirely general terms and will not be explained in more detail in this application.

The drive devices according to the invention comprise an elongated adjusting element, at least one turning point and a drive unit. The turning point is connected to and/or is composed of a portion of the basic body. The adjusting element is connected to at least one line and extends round the turning point. The line may be any kind of line in connection with a trawl, for example warp or sweep, a common line for several trawl bags, a line for a single trawl bag or a line at the trawl bag opening. The drive unit is connected with the adjusting element in order to move it relative to the basic body.

The drive units are controlled by means of a control unit, which in turn is arranged for receiving orders from the boat or from status sensors that monitor the trawl position. The control unit is adapted to process such orders/test signals and provide control signals for the drive unit.

The invention also comprises an adjusting device for dynamic adjustment of one or more trawl bags during a trawl operation, comprising a basic body, arranged, for example, for connection between a towline (warp) and at least one line to a point on a trawl bag (sweep). The basic body comprises at least one drive device as indicated above.

In the drive devices and the adjusting device according to the invention the drive unit may provide a rotating and/or linear motion for movement of the adjusting element relative to the basic body. A rotating motion of the adjusting element is achieved, for example, by the drive unit rotating about a point and the adjusting element placed in abutment round the drive unit. In addition or as an alternative, the drive unit may provide a linear motion of the adjusting element relative to the basic body, for example by the drive unit preferably being progressively movable relative to the basic body. A variant may be envisaged where the drive unit is linearly movable relative to the basic body while including a rotating motion of the adjusting element. In a second variant of the invention at least one turning point and/or drive unit may preferably be progressively movable relative to the basic body. Another variant may be envisaged where the drive unit is composed of a drum device on the basic body that winds up and pays out the adjusting element during a trawl operation.

In a variant of the devices according to the invention they comprise a closed adjusting element which extends round at least two turning points in connection with the basic body, but another variant may be envisaged where the device comprises an open adjusting element with at least one turning point to one line and one attachment point to a second line or the basic body. In some embodiments there will be a fixed attachment point between the line and the adjusting element, while in other cases the attachment point between the line and the adjusting element will be moved along the adjusting element. It is also possible for the adjusting element to be composed of a portion of a line.

In an embodiment of the invention the drive unit is mounted in a turning point for the adjusting element. In another embodiment of the invention the drive unit is mounted in an attachment point between the adjusting element and a line. Another scenario may be for the drive device to be located on the basic body and not form a turning point for the adjusting element.

According to the invention a device comprising drive devices according to the invention will be employed for adjusting forces on lines in the system of at least one trawl. The forces can be adjusted in the horizontal and/or vertical direction, thereby achieving a wide range of adjustment possibilities for the trawl system.

The drive unit in the devices according to the invention may be electrically, hydraulically and/or mechanically operated. The electricity may be provided by batteries, cables to the vessel and/or a separate energy-generating device, the same as for hydraulic operation of the drive unit. With regard to mechanical operation, a mechanical connection may be envisaged up to the vessel for mechanical adjustment, where, for example, a pull-out arrangement may be envisaged that is drawn back after a certain amount of pulling, devices for rotating motion by pulling on lines from one or two sides, etc. The drive unit is preferably electrically operated.

In a preferred embodiment of the devices according to the invention they comprise an energy-generating device. Different variants may be envisaged here, one variant being a basic body including an energy-generating device, which comprises a roller device for exploiting the relative movement of the basic body in relation to the seabed, or alternatively the energy-generating device may comprise a turbine device for generating energy from the fluid flowing past.

One of the advantages of an energy-generating unit in connection with the basic body is that the trawl can be in use for a longer period, for example without having to replace batteries for operating the drive unit.

In an embodiment of the invention the adjusting element may be connected to two different basic bodies for simultaneous adjustment of two or more basic bodies. This common adjustment may be achieved by the turning point for the device being composed of the attachment point for a line and where the drive unit's engagement with the adjusting element is arranged at the same point. In this case the drive unit may be composed of an electric drive unit or a mechanical unit which may be composed of a line up to the vessel which adjusts the turning point in a linear motion relative to the basic bodies when the line is paid out/pulled in, thereby adjusting the forces acting on the basic bodies and thereby adjusting the trawl bag opening.

The invention also comprises a trawl system comprising two or more trawl bags during a trawl operation. In connection with at least one of the lines for the trawl bags and/or the trawl bags, the system comprises a device as indicated above for adjusting the trawl bags.

The invention also comprises a method for controlling the opening of at least one trawl bag during trawling, where the trawl bag's basic bodies comprise at least one drive device according to that indicated above, and the trawl bag and/or basic bodies, lines or winches on the vessel etc. are equipped with at least one status sensor. A sensor reads a status, a test signal is transmitted from the sensor to a control unit, which sends a signal to the adjusting devices' drive units for adjusting the device's position as a consequence of the sensor reading. The method may comprise an interface for an operator, who can control or overrule the system. The method is performed continuously, at given intervals, or in the event of a change in the sensor reading. The invention also comprises a system for controlling basic bodies in connection with a trawl and/or the opening of at least one trawl bag during trawling, where the trawl bag's basic bodies comprise at least one device according to the invention, and the trawl bag and/or basic bodies, lines or winches on the vessel etc. comprise at least one sensor in connection with the trawling process, a control unit connected to the sensor(s) and at least one drive unit connected to the control unit, where the control unit is arranged to control the drive unit on the basis of the sensor readings.

The adjusting device according to the invention for adjusting one or more basic bodies for one or more trawl bags may be employed for adjusting the basic body's location in the body of water, and it may also be employed, for example, to make a basic body go deeper down into the seabed in order to stir up mud from the seabed and thereby collect the fish in a desired area. In general it may be employed, as stated above, for adjusting the forces on the basic bodies, thus adjusting their position and thereby the opening of the trawl bags.

The invention provides good control of the trawl bags. The degree of adjustment that can be obtained by means of the invention depends on the length of the adjusting element, the distance between turning points and the type of drive unit in the practical implementation of the invention.

The invention will now be explained in greater detail in relation to a preferred embodiment with reference to the attached drawings, in which:

Fig. 1 is a schematic view of a vessel towing at least one trawl with devices according to the invention.

Fig. 2 is a schematic view of a trawl from above.

Fig. 3 is a schematic view of a basic body with an embodiment of the drive device according to the invention.

Fig. 4 is a schematic view of a basic body with a second embodiment of the drive device.

Fig. 5 is a schematic view of a basic body with a third embodiment of the drive device.

Fig. 6 is a schematic view of two basic bodies with a fourth embodiment of the drive device.

Fig. 7 is a schematic view of a control system for use in the method according to the invention. As illustrated in fig. 1 the invention relates to a device for adjustment of a trawl 2 dragged by a vessel 1 in connection with a trawl operation. The trawl 2 is connected to the vessel 1 by at least one line 3. In this context the term line 3 should be understood to refer to all types of lines in connection with a trawl and trawl operation. A line 3 may be a chain or wire made of Kevlar or another type of material.

Fig. 2 is a schematic illustration of a trawl 2. In a trawl operation a plurality of trawls may be employed arranged alongside and/or above one another. The trawl 2 may be a pelagic or a bottom trawl 2. The trawl opening for the trawl is controlled and adjusted by basic bodies 5, other words for basic body being, for example, doors, weights, centre weights, roller weights, wings, etc. A basic body 5 is connected to a line 3 in connection with the trawl 2. The forces acting on the basic body and thereby also on the trawl are controlled by devices according to the invention.

Figures 3-6 schematically illustrate four different versions of the drive device 10 according to the invention. The basic body 5 is illustrated in all the figures in an entirely schematic fashion. It should be understood that a basic body 5 may also be equipped with more than one drive device 10 according to the invention even though in all the figures only one drive device 10 is illustrated in connection with each basic body 5. The drive device 10 according to the invention comprises an adjusting element 1 1 , a turning point 12 and a drive unit 13. The drive device 10 constitutes a connection between a line 3 and the basic body 5.

As illustrated in fig. 3, in a first embodiment the drive device 10 may comprise a closed adjusting element 1 1, which extends round a turning point 12 on the basic body 5 and a drive unit 13 also mounted on the basic body 5. In this embodiment the drive unit 13 also constitutes a turning point 12. The adjusting element 1 1 is firmly connected to the lines 3 at an attachment point 14. In this embodiment the drive unit 13 influences the adjusting element 1 1 with a rotating motion indicated by arrow A. By rotating the adjusting element 1 1 relative to the drive unit 13, the angles and resultant force on the basic body 5 will be changed, thus enabling its position and influence on the trawls to be adjusted.

Fig. 4 illustrates a second variant of the drive device 10, where the adjusting element 1 1 is an open adjusting element and secured to the basic body 5 at an attachment point 15. From the attachment point 15 the adjusting element 1 1 extends round a turning point 12, which in this case also constitutes a drive unit 13. At its other end the adjusting element 1 1 is secured to the line 3 at an attachment point 14. In this embodiment the adjusting element 1 1 may be composed of a portion of the line 3. In this embodiment it is indicated that the drive unit 13, which also constitutes the turning point 12, is linearly movable relative to the basic body 5, illustrated by arrow B. By altering the drive unit in this manner the adjusting element 1 1 will be moved relative to the drive unit and the resultant force on the basic body 5 is changed.

A third variant of the invention is illustrated in fig. 5, where the adjusting element 1 1 is an open element, where both ends of the adjusting element 1 1 are secured to the basic body 5 at attachment points 15. The adjusting element 1 1 extends from an attachment point 15 round a turning point 12, which also forms a drive unit 13, to the second attachment point 15 on the basic body 5. The turning point 12 and the drive unit 13 are secured to the line 3, thus providing a free and possibly progressive attachment of the adjusting element 1 1 to the line 3. By moving the adjusting element 1 1 relative to the drive unit 13, the resultant force on the basic body 5 is changed, thus enabling its position to be adjusted.

In a fourth embodiment of the invention as illustrated in fig. 6, the invention is employed for adjusting two basic bodies 5 and 5'. An adjusting element 1 1 is connected to two basic bodies 5 and 5' at attachment points 15, at each end of the open adjusting element 1 1. The adjusting element extends round a turning point 12, which also constitutes a drive unit 13. The turning point is connected to the line 3. In this embodiment the drive unit 13 can influence the adjusting element 1 1 by a rotational motion indicated by arrow A, thus causing the adjusting element 1 1 to change its position relative to the drive unit 13 and also, or as an alternative, by a linear motion marked by arrow B, which also causes a change in the position of the adjusting element 1 1 relative to the drive unit 13 by changing the adjusting element's 1 1 angle about the turning point 12, and changing the resultant forces on the basic bodies 5 and 5'. A linear motion of this kind may be achieved by pulling or releasing the lines 3 relative to the vessel. In this manner a wide range of adjustment possibilities are achieved for the basic bodies with a drive device according to the invention.

As illustrated in fig. 7 the invention also comprises a control system for controlling basic bodies and the opening of at least one trawl bag during trawling. The trawl bag's basic bodies comprise at least one drive device as explained above and the trawl bag and/or basic bodies, lines or winches on the vessel, etc. comprise at least one sensor. This may, for example, be a position or status sensor. A control unit is connected to the sensor(s), and at least one drive unit in a drive device is connected to the control unit, where the control unit is arranged for control of the drive unit based on the sensor readings. The invention has now been explained by means of four embodiments. A number of variants of these embodiments of the invention may be envisaged within the scope of the invention as defined in the following claims. For example, the adjusting element may be composed of a portion of a line, where the lines are joined at an attachment point 14, as indicated in fig. 3. It is possible for the basic body to be provided with a plurality of drive devices for adjusting different lines attached to the basic body. The lines may be in connection with the towlines from the vessel. It is also possible for the lines to be only one line extending to a portion of the trawl opening and that the basic body is a so-called wing. One possible variant is to employ drive devices according to the invention for elements mounted in the trailing edge of the trawl bag. The drive unit may be envisaged composed of a drum device on the basic body. It is also possible for the drive device to comprise several drive units. A variant where there are more than two turning points is also conceivable. The position of the turning points and the attachment points relative to the basic bodies must be determined for the individual basic bodies as the position will also be dependent on the shape of the basic bodies and the hydrodynamic forces acting on the basic bodies when they are dragged through the body of water. The drive device may also be arranged in such a manner that the adjusting element is open and attached to the ends of two different lines, with turning point and drive device on the basic body.

Claims

1. A drive device (10) for dynamic adjustment of a basic body (5) in connection with one or more trawl bags (2) during trawling, characterised in that it comprises an elongated adjusting element (1 1), at least one turning point (12) and a drive unit (13), where the adjusting element (1 1 ) is mounted between at least one line (3) and the basic body (5), extends round the turning point (12) and is engaged with the drive unit (13) in order to change the adjusting element's (1 1) position relative to the basic body (5), and that the drive unit is controlled by acoustic signals from a boat or directly in response to readings from sensors placed beside the trawl.

2. An adjusting device for dynamic adjustment of one or more trawl bags (2) during a trawl operation, comprising a basic body (5), for example arranged for connection between a towline (warp) and at least one line (3) to a point on a trawl bag (sweep), characterised in that the basic body (5) comprises at least one drive device (10), with an adjusting element (1 1), at least one turning point (12) and a drive unit (13), where the adjusting element (1 1) is mounted between at least one line (3) and the basic body (5), extends round at least one turning point (12) and is engaged with the drive unit (13) in order to change the adjusting element's (1 1) position relative to the basic body (5), and where the drive unit is controlled by acoustic signals from a boat or directly in response to readings from sensors placed beside the trawl.

3. A drive device (10) for dynamic adjustment of at least two basic bodies (5, 5') in connection with one or more trawl bags (2) during trawling, characterised in that it comprises an elongated adjusting element (1 1), at least one turning point (12) and a drive unit (13), where the adjusting element (1 1 ) is mounted between at least one line (3) and two basic bodies (5, 5'), extends round the turning point (12) and is engaged with the drive unit (13) in order to change the adjusting element's (1 1) position relative to the basic bodies (5), and where the drive unit is controlled by acoustic signals from a boat or directly in response to readings from sensors placed beside the trawl.

4. A device according to one of the preceding claims, characterised in that the drive unit (13) provides rotating and/or linear motion in order to change the adjusting element's (1 1) position relative to the basic body (5).

5. A device according to claim 1 or 2, characterised in that it comprises a closed adjusting element (1 1), which extends round at least two turning points (12).

6. A device according to claim 1 or 2, characterised in that it comprises an open adjusting element (1 1) with at least one attachment point (14) to a line (3) and one attachment point (15) to a second line (3) or the basic body (5).

7. A device according to one of the above-mentioned claims, characterised in that there is a fixed attachment point (14) between the line (3) and the adjusting element (1 1).

8. A device according to one of the above-mentioned claims, characterised in that the drive unit (13) is mounted in a turning point (12) for the adjusting element (1 1) and/or that the drive unit (13) is mounted in an attachment point (14) between the adjusting element (1 1) and a line (3).

9. A device according to one of the above-mentioned claims, characterised in that at least one turning point (12) and/or drive unit (13) is progressively movable relative to the basic body (5).

10. A device according to claim 2, characterised in that it comprises drive devices (13) in order to exert forces in a horizontal or vertical direction on the device for adjusting forces acting on lines (3) attached to the basic body (5).

1 1. A device according to one of the above-mentioned claims, characterised in that the drive unit (13) is electrically, hydraulically and/or mechanically operated.

12. A device according to claim 2, characterised in that it comprises an energy-generating device.

13. A device according to one of the above-mentioned claims, characterised in that the basic body (5) comprises an energy-generating device including a roller device for exploiting the relative movement of the basic body (5) relative to the seabed.

14. A device according to one of the claims 12 or 13, characterised in that the energy-generating device comprises a turbine device.

15. A trawl system comprising two or more trawl bags (2) during a trawl operation, characterised in that it comprises a device (10) as indicated in claim 1 for adjusting the position of the trawl bags (2) in connection with at least one of the lines (3) for the trawl bags (2) and/or the trawl bags (2).

16. A method for controlling the opening of at least one trawl bag (2) during trawling, where the trawl bag's basic bodies (5) comprise at least one device (10) according to claim 1, 2 or 3, and the trawl bag (2) and/or basic bodies (5), lines (3) or winches on the vessel (1) etc. are equipped with at least one status sensor, characterised in that a sensor reads a status, a test signal is transmitted from the sensor to a control unit, which sends a signal to the drive device's drive units (13) for adjustment of the adjusting element's (1 1) position as a consequence of the sensor reading.

17. A method according to claim 17, characterised in that the control unit comprises an interface for an operator.

18. A method according to claim 17, characterised in that it is performed continuously, at given intervals or in the- event of a change in the sensor reading.

19. A control system for controlling basic bodies (5) in connection with a trawl (2) and/or the opening of at least one trawl bag (2) during trawling, where the trawl bag's basic bodies (5) comprise at least one device (10) according to claim 1, 2 or 3, and the trawl bag (2) and/or basic bodies (5), lines (3) or winches on the vessel (1) etc. comprise at least one sensor in connection with the trawling process, a control unit connected to the sensor(s) and at least one drive unit (13) connected to the control unit, where the control unit is arranged for control of the drive unit (13) based on the sensor readings.