WO2004082375A1

WO2004082375A1 - Otter board

Info

Publication number: WO2004082375A1
Application number: PCT/FR2004/000576
Authority: WO
Inventors: Hélène MORGERE-PODEUR
Original assignee: Etablissements Morgere
Priority date: 2003-03-12
Filing date: 2004-03-11
Publication date: 2004-09-30
Also published as: EP1603387A1; FR2852200B1; FR2852200A1; IS8041A; CA2518670A1; NO20054699L

Abstract

The invention relates to an otter board (1) with a generally oval contour, having a length to height ratio of approximately 1.3 to 1.5 inclusive, with a pair of dished foils (3, 4), whilst the remainder (2) of the wall thereof is solid. The intermediate foil (3) is provided with a bracket (7) on the ventral face thereof, for the attachment of a trawl warp, the opposing face of the board called the dorsal face comprises fixing means for the attachment to the trawl bridle. The transverse section of the above has the approximate form of a dihedral, the intersection of which runs horizontally, essentially along the medial longitudinal axis thereof, the angle of which lies between approximately 165° and 175° and is open to the dorsal face thereof. Said board is suitable for low-speed fishing, particularly fishing for shrimps in cold waters.

Description

TRAWLING PANEL

The present invention relates to a trawl panel. More precisely, it relates to a trawl panel, which allows fishing on the seabed as well as pelagic fishing, or semi-pelagic fishing, during which the trawl net is taken off from the seabed, at a depth more or less great depending on the type of fishing.

The invention further relates to a trawl panel which makes it possible to fish in cold waters, which may be partially frozen on the surface, as is the case, for example, for shrimp fishing in seas close to the Arctic Circle. .

For this type of fishing, there is a particular problem due to the fact that the progress of the fishing boat which tows the trawl can be greatly slowed down, or even stopped, because of ice patches likely to clog the surface of the water. . This is why, the objective of the present invention is to provide a trawl panel whose shape and structure do not compromise the proper functioning of the trawl assembly, even in unfavorable conditions of extreme cold, while also effective in ordinary fishing configurations, both on the bottom and in pelagic or semi-pelagic fishing conditions.

The trawl panel which is the subject of the invention has, as is known per se (see for example the document FR 1 595 458), a general oval outline.

The objectives which have just been mentioned are achieved thanks to the fact that:

- the ratio of its length to its height is between 1.3 and 1.5 approximately;

- It comprises in the front part a pair of deflecting vanes, or "foils", of curved shape, which provide on their rear edge a transverse slot authorizing and channeling the passage of water; - its wall is full over an area extending over at least its entire rear half;

- The foil located between this solid area and the most forward foil is provided on its concave face - said ventral - with a fixing means, or branch allowing it to be attached to a traction fungus of a fishing boat; - the opposite - so-called dorsal - face of the panel carries fixing means allowing it to be attached to the arm of a trawl.

- The cross section of the panel takes the form of a dihedron whose edge extends horizontally, substantially along its median longitudinal axis, and whose angle is open on the side of its dorsal side, this angle having a value included between 165 ° and 175 ° approximately, and preferably of the order of 172 °.

Furthermore, according to a certain number of advantageous, but not limiting, characteristics of the invention:

- Said solid wall area is also curved, its concavity, like that of the two foils, being directed on the same side, corresponding to the ventral face of the panel, all these curvatures being registered approximately according to cylinder portions of transverse axis and vertical;

- These lower and upper portions are full and are separated, on the side of the ventral side, from the central portion of the panel, by longitudinal horizontal ribs which delimit the upper and lower ends of said slots;

- H being the height of the panel, its full upper portion extends over a height (j) whose value is between 0.12 H and 0.15 H approximately;

- H being the height of the panel, its full lower portion extends over a height (k) whose value is between 0.15 H and 0.19 H approximately; - Said branch has at least two possible attachment areas of warp offset in height, one located at its median longitudinal axis, the other slightly below the latter.

Other characteristics and advantages of the invention will appear on reading the description and the accompanying drawings. In these drawings:

- Figures 1 and 2 are views, respectively, of the dorsal side and the ventral side of the panel;

- Figures 3 and 4 are perspective views, respectively of the dorsal side and the ventral side of the panel; - Figure 5 is an end view (rear view) in perspective of the same panel;

- Figures 6 and 7 are schematic sectional views of the panel, along the transverse and longitudinal section planes respectively designated VI-VI and Vu-Vil of Figure 8; - Figure 8 is a schematic front view of the same panel

(visible ventral side); - Figure 9 is a diagram illustrating a trawl fishery in which use is made of a pair of panels according to the invention.

The trawl panel shown in the figures, referenced 1, has a face (la) called ventral and an opposite face (1b) called dorsal. This panel has a general oval shape.

The panel shown in Figures 1 to 8 is a port panel, capable of ensuring the opening of the trawl pocket on its left side when towed by a fishing boat. This panel therefore corresponds to that designated 1A in FIG. 9, while in this figure the other panel, referenced 1B, is a starboard panel. The left and right panels are similar but have a reverse configuration, symmetrical to each other.

Still with reference to FIG. 9, the reference BP has designated a fishing boat which tows the trawl 9. In this figure is represented a fishing operation on the seabed S. The trawl 9, which consists of a net pocket shape, is towed by the BP boat which sails on the N surface of the water. The role of the two trawl panels 1A and 1B is to keep the pocket suitably open during fishing, thanks to the hydrodynamic effect linked to the advancement of the boat and to the friction of the water against the ventral faces of the panels. These panels are connected to the boat by cables 90A, 90B respectively called "warps". They are connected by their dorsal side to the trawl 9 by lines 91A, respectively 91B, traditionally called "trawl arms".

The front edge - or leading edge - of the panel has been designated in FIGS. 1 and 2 by the reference 10, while its rear edge - or trailing edge is marked with the reference 11. These lower and upper edges are respectively designated 12 and 11.

As can be seen in these figures, the radii of curvature of the leading and trailing edges are substantially smaller than those of the upper and lower edges.

As is well known, the lower edge 12 is lined with a series of adjacent removable soles 120. These are sliding shoes on the ground, capable of being changed when they are damaged or worn. The arched shape of the lower edge 12 facilitates the passage of obstacles that may be on the seabed, such as rocks in particular, limiting the risk of blockage.

In FIG. 8, the length and the width of the panel have been designated by the references L and H respectively. Thereafter, we will call this width "height" means the vertical or approximately vertical position of the panel during use.

According to an important characteristic of the invention, the L / H ratio is between 1.3 and 1.5 approximately. It is preferably of the order of 1.4. This shape and this ratio make it possible to obtain a good compromise between the hydrodynamic drag of the panel and its ability to keep the trawl correctly open.

As can be seen in particular in FIGS. 1 and 2, the panel 1 is subdivided lengthwise into three zones, namely a rear zone 2, which extends over a little more than half of the panel, a zone front 4, and an intermediate zone 3. These three zones are themselves delimited, on the ventral face la, by high longitudinal 15 and low horizontal ribs 16. A median longitudinal rib 14 is also provided which extends substantially along a longitudinal median axis from the leading edge to the trailing edge of the panel. As can be seen more particularly in FIG. 7, the parts 2,

3 and 4 are bent. They have a cylindrical portion shape, with a transverse axis, their concavity being directed towards the side of the ventral face la. The previous parts 3 and

4 constitute deflecting vanes, or foils, and the passage of the water in use can be done in interstices or transverse slots 30, respectively 40, which respectively separate parts 4 and 3 on the one hand and 3 and 2 on the other hand.

The height of these slots is limited upwards and downwards by the above-mentioned ribs 15, respectively 16.

The areas above and, respectively, below the ribs 15 and 16 are full. Their height bears the reference j, respectively k. Preferably, j is between 0.12 and 0.15 H approximately and k between 0.15 and 0.19 H approximately.

It will be noted (see FIG. 2) that on the side of the ventral side, the foil 4 has a certain number of longitudinal ribs 40. Furthermore, on the side of the dorsal side (see FIG. 1), longitudinal ribs 20 and 30 respectively on portions 2 and 3.

In addition, the foil 3 carries, on its ventral side, a system 7 allowing the attachment of the warp.

This attachment system comprises two longitudinal parallel plates 71, respectively 70 which are offset in height. Plate 71 is located in the extension of the central rib 14, in the center line of the panel, while the other plate 70 is located slightly below the plate 71.

In these plates are provided openings 710 which allow the passage and the attachment of the end of the pulling surface of the panel. Such a system is usually called "branch".

This panel therefore has two branches offset in height.

The lower branch 70 is advantageously used for fishing on a shallow bottom which requires a very long spinning (3 to 5 times the water height approximately) for which there would otherwise be a problem of tilting the panel inwards , this tilting being in particular linked to the weight of the warps.

For shorter lengths, use the upper branch 71.

The combination of the front foils 4 and 3 with a solid part 2, which extends over more than half of the panel, and in a way forms a main foil, makes it possible to obtain an optimal compromise between the drag and the lift.

According to an important characteristic of the invention, as can be seen in particular in FIGS. 5 and 6, the panel, seen at the end, has the general shape of a very open angle dihedral a, the opening of which is directed towards the side of the back side lb of the panel. Its edge is located along a horizontal center line, corresponding to the rib 14.

Preferably the value of the angle a is of the order of 172 degrees.

On this dorsal face, attachment tabs 8 are fixed for the trawl arm. In the example illustrated, provision is made for a front central tab 8 ′ and a pair of high and low rear tabs 8a, 8b.

There are also two additional 8 "high and low front lugs.

Depending on the conditions of use, and the habits of the user, it is possible to provide for a triangle or rectangle attachment of the trawl arm by selectively using only some of these five attachment points.

Thus, using the attachment points 8 ′, 8a and 8b, a triangular connection of the trawl arm with the panel is ensured.

In use, when the panel moves on the bottom, its soles 120 rubbing on the seabed F (see Figure 6) the panel has a natural tendency to move outward, that is to say towards the dorsal side - which corresponds to a direction of opening of the trawl - even if the fishing boat is moving at a low speed, even very low, which can be between 0 and 2 knots.

This situation is encountered in particular when fishing in icy waters, especially shrimp fishing. In the absence of a dihedral configuration, the panel would risk, at such a low speed, of bringing together or even crossing of the two panels, causing an undesirable entanglement of the warps and the arms of the trawl.

A difficulty also arises when the boat hits a crust of ice, which makes it stop suddenly.

There is then a risk that the panel will lay flat on the seabed.

In this hypothesis, it is generally the ventral side 1a which comes to bear on the bottom.

When the boat restarts, a flat panel may not straighten properly.

Thanks to its dihedral shape, the panel has a natural tendency to rise when restarted, and it gently returns to its normal working position, which is substantially vertical.

The panel which is the subject of the invention thus makes it possible to work in good conditions, whatever the fishing situation with which we are dealing, both at low speed and at high speed.

Claims

1. Trawl panel which has a general oval outline, characterized in that:

- the ratio of its length (L) to its height (H) is between 1.3 and 1.5 approximately; - it comprises in the front part a pair of deflecting vanes, or

"foils" (3, 4), of curved shape, which provide on their rear edge a transverse slot (30, 40) authorizing and channeling the passage of water;

- Its wall is full over an area (2) extending over at least its entire rear half; - the foil (3) located between this solid zone (2) and the most forward foil

(4) is provided on its concave face - called ventral side - with a fixing means, or branch (7), making it possible to attach it to a traction funnel (90) of a fishing boat (BP);

- the opposite face (lb) - called dorsal - of the panel carries fixing means allowing it to be attached to the arm (91) of a trawl;

- The cross section of the panel (1) assumes the shape of a dihedral whose edge extends horizontally, substantially along its median longitudinal axis, and whose angle (a) is open on the side of its dorsal face, this angle having a value between approximately 165 ° and 175 °, and preferably of the order of 172 °.

2. Trawl panel according to claim 1, characterized in that said solid walled zone (2) is also curved, its concavity, like that of the two foils (3, 4) being directed on the same side, corresponding to the ventral side (la) of the panel (1) all these curvatures being registered approximately according to cylinder portions of transverse and vertical axis.

3. Trawl panel according to claim 1 or 2, characterized in that its upper (5) and lower (6) portions are full and are separated, on the side of the ventral side (la), from the central portion of the panel , by longitudinal horizontal ribs (15, 16) which delimit the upper and lower ends of said slots (30, 40).

4. Trawl panel according to claim 3, characterized in that, H being the height of the panel, its solid upper portion (5) extends over a height (j) whose value is between 0.12 H and 0.15 am approximately.

5. Trawl panel according to claim 3 or 4, characterized in that, H being the height of the panel, its solid lower portion (6) extends over a height (k) whose value is between 0.15 H and 0.19 H approximately.

6. Trawl panel according to one of claims 1 to 5, characterized in that said branch (7) has at least two fune attachment zones (71, 72) offset in height, one (71) located at level of its median longitudinal axis, the other (70) a little below the latter.