GB2173381A - Trawl door - Google Patents

Abstract

A trawl door (1) comprises a body (1a) having a first body part (26) and a second body part (25). The first body part (26) is removably secured to the second body part (25) to enable the size of the door (1) to be adjusted. <IMAGE>

Description

SPECIFICATION Improvements relating to trawl doors This invention relates to trawl doors (sometimes called "trawl boards" or "otter boards"), including intermediate doors (sometimes called "poney doors"), which are used to control the trawls used in trawling.

In modern day trawling it is common for a trawler to need to change from catching one type of fish to another. This requires different nets having different drag loads which in turn requires different sizes of trawl door.

In the past this problem has been solved either by each trawler having two pairs of doors of different size, or by having one pair of doors at a size intermediate the two required sizes.

According to the present invention there is provided a trawl door having a body, wherein the size of the body is adjustable.

This enables the surface area of the door to be increased or decreased in order to suit the needs of a particular type of trawling, or trawler.

Advantageously the body comprises at least first and second body parts which are adapted to be removably secured to one another.

Thus, for example, the size of the door can be adjusted by removing one or more of the body parts.

Thus, the second body part may be replaced with a third body- part having a size which is different to the second body part in order to increase or decrease the size of the door.

Desirably, the trawl door further includes an intermediate body part which is adapted to be disposed between the first and second body parts, and which can be removably secured to the first and second body parts.

The intermediate body part may be replaced with a further intermediate body part having a size which is different to the size of the intermediate body part in order to increase or decrease the size of the door.

If desired, more than one intermediate body part may be simultaneously disposed between the first and second body parts.

The first body part may correspond to a lower part of the trawl door, and the second body part may correspond to an upper part of the trawl door.

Preferably securing means is provided for securing the body parts to one another. The securing means may comprise a flange provided on at least one edge of each body part; each flange may be provided with a plurality of apertures. The flanges on adjacent body parts can be arranged in engagement with one another, such that the apertures on adjacent flanges are in alignment. Fixing means, such as bolts, can be passed through the aligned apertures to secure the adjacent body parts to one another.

The door may be provided with upper and lower edges and may have a front face and a rear face. The front face may be provided with means for attaching a trawl warp and the rear face may be provided with means for attaching backstrops which are secured to a trawl net.

The means for attaching the trawl warp may comprise a member pivotally mounted on the front face of the body. Preferably the means for attaching the trawl warp is mounted to the first body part. A resilient connection may be provided between the member and a point on the front face between the member and the rearward end of the trawl door. This is described my United Kingdom patent number 2,115,661.

The body parts may be secured to one another along an axis substantially parallel to the longitudinal axis of the trawl door.

The trawl door of the present invention enables the size of door to be altered. Hence it is not necessary for a trawler to carry two or more pairs of doors in order to conduct different types of fishing.

Reference is now made to the accompanying drawings in which: Figure 1 is a perspective view of a trawl door according to the invention; Figure 2 is a perspective exploded view of a trawl door according to one embodiment of the invention; Figure 3 is a perspective exploded view of a trawl door according to a further embodiment of the invention; and Figure 4 is a view along lines 4-4 of Fig. 1.

Referring to Fig. 1, a trawl door generally designated 1 comprises a body 1a having two detachable- shoes 2 and 2a provided along the base thereof.

A member 3 is attached to a D-link 50 which passes through an apertured bar 51.

The bar 51 is mounted on rods 52 which are in turn mounted upon projections 53 and 54.

The rods 52 are surrounded by washers 55, and the washers can be removed in order to alter the position of the bar 51 with respect to the projections 53 and 54. A resilient connection 12 is attached to a pin generally designated 60 which fits between apertures 57 and 59 in the projections 53, 54 respectively. The pin 60 is surrounded by washers 61, and the washers are removable so that the point at which the resilient connection 12 is attached to the pin can be altered. It is also possible to locate the pin 60 between apertures 56 and 58.

The projections 53 and 54 are provided on a front face 20 of the door 1. The body 1 a is provided with an upper edge 1 b and a lower edge 1 c.

A slot 14, which contributes towards the good hydrodynamic properties of the door, is situated at the forward end of the trawl door 1. A trawl warp (not shown) can be connected to the trawl door 1 through aperture 3a of the member 3, and can also be fixed to a trawler (not shown).

Projections 19 and 20 are provided near the base of the front face 20 of the door 1. Between these projections 19 and 20 ballast (not shown) may be stored. Removable pins (not shown) between the projections 19 and 20 serve the purpose of holding the ballast in position. An additional projection 1 9a is provided so that extra ballast may be stored between the projections 19 and 19a.

The trawl door 1 can be lifted by attaching a rope around a hook 11. The hook 11 is positioned so that the trawl door 1 will hang substantially vertically as it is lifted through the air.

Backstrops may be attached to a rear surface (not shown) of the door 1.

The features so far described are all disclosed in my earlier U.K. Patent number 2,115,661.

The body 1a comprises first body part 26 to which a second body part 25 is removably secured. The second body part 25 is provided with securing means in the form of a flange 27, and the first body part 26 is provided with securing means in the form of a flange 28. The flanges 27 and 28 are each provided with a plurality of apertures 29. The flanges 27 and 28 engage one another so that the apertures 29 are aligned, and fixing means in the form of bolts 30 are passed through the apertures 29 in order to secure the second body part 25 to the first body part 26. The body part 25 can be separated from the body part 26 by removing the bolts 30.

In the embodiment shown in figure 2, the second body part 25 has been replaced with a third body part 70. The third body part 70 is identical to the second body part 25, except that it is larger. In view of this like parts have been designated with like reference numerals.

Accordingly, the size of the door 1 can be increased by removing the second body part 25 from the first body part 26 and then securing the third body part 70 to the first body part 26. This can be achieved by engaging the flange 27 of the third body part 70 with the flange 28 of the first body part 26 so that the apertures 29 are aligned, and then passing the bolts 30 through the apertures 29 (see Fig.

4).

It will be appreciated that the third body part 70 could be of smaller size than the second body part 25 in order to reduce the size of the door 1.

It is necessary to replace the rods 52 carrying the washers 55 with rods of a size suited to the size of the third body part 70. The position of the member 3 with respect to the front face 20 of the door 1 can be adjusted to suit the needs of the new size of door.

Figure 3 shows a further embodiment in which an intermediate body part 80 is disposed between the first body part 26 and the second body part 25. The intermediate body part 80 includes an upper edge 81 from which projects securing means in the form of a flange 82 and a lower edge 83 from which projects securing means in the form of a flange 84. The flanges 82 and 84 are each provided with apertures 29, which are of the same dimensions as the apertures 29 in the flanges 27 and 28.

When the second body part 25 has been separated from the first body part 26, then the intermediate body part 80 may be disposed between the body parts 25 and 26 so that the flange 82 engages the flange 27 of the second body part, and so that the flange 84 engages the flange 28 of the first body part. The flanges 27, 28, 82 and 84 can be arranged so that the apertures 29 are aligned, and the bolts 30 may then be passed through the apertures 29 in order to secure the second and first body portions 25 and 26 to the intermediate body part 80. This enables the size of the door 1 to be increased.

It will be appreciated that further intermediate body parts can be provided between the first and second-body parts 26 and 25.

The first body part 26 of the body la corresponds to a lower part of the- body 1a, and the second body part 25 corresponds to an upper part of the body 1a.

The body parts are secured to one another along an axis substantially parallel to the longitudinal axis of the door 1, i.e. an axis through the front and rear edges substantially parallel to the upper and lower edges 1b and 1c.

Claims (15)

1. A trawl door having a body, wherein the size of the body is adjustable.

2. A trawl door according to claim 1, in which the body comprises at least first and second body parts, said first and second body parts being adapted to be removably secured to one another.

3. A trawl door according to claim 2, in which the second body part is replaceable with a third body part having a size which is different to the size of the second body part.

4. A trawl door according to claim 2 or 3, further comprising an intermediate body part which is disposed between the first and second body parts, and which is removably secured to the first and second body parts.

5. A trawl door according to claim 4, in which the intermediate body part is replacea ble with a further intermediate body part having a size which is different to the size of the intermediate body part.

6. A trawl door according to any of claims 2 to 5 further comprising securing means for securing the body parts to one another.

7. A trawl door according to claim 6, in which the securing means comprises a flange provided on at least one edge of each body part.

8. A trawl door according to claim 7, in which the flange is provided with a plurality of apertures.

9. A trawl door according to claim 8, in which the flanges on adjacent body parts are arranged in engagement with one another, such that the apertures on adjacent flanges are in alignment.

10. A trawl door according to claim 9, in which fixing means are passed through the aligned apertures to secure the adjacent body parts to one another.

11. A trawl door according to any of claims 2 to 10 in which the body parts are secured to one another along an axis substantially parallel to the longitudinal axis of the door.

12. A trawl door according to any preceding claim further comprising means for attaching a trawl warp to the door.

13. A trawl door according to claim 12, in which the means for attaching a trawl warp comprises a member pivotally secured to the body.

14. A trawl door according to any preceding claim further comprising means for attaching backstraps to the door.

15. A trawl door substantially as herein described with reference to and as shown in the accompanying drawings.