WO2006087736A1 - Chalut large presentant des caracteristiques ameliorees d'ouverture de la bouche et de l'extremite arriere - Google Patents

Chalut large presentant des caracteristiques ameliorees d'ouverture de la bouche et de l'extremite arriere Download PDF

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Publication number
WO2006087736A1
WO2006087736A1 PCT/IS2006/000004 IS2006000004W WO2006087736A1 WO 2006087736 A1 WO2006087736 A1 WO 2006087736A1 IS 2006000004 W IS2006000004 W IS 2006000004W WO 2006087736 A1 WO2006087736 A1 WO 2006087736A1
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WO
WIPO (PCT)
Prior art keywords
trawl
panel
mesh
self
mesh bars
Prior art date
Application number
PCT/IS2006/000004
Other languages
English (en)
Inventor
Sherif Safwat
Original Assignee
Candis Ehf.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Candis Ehf. filed Critical Candis Ehf.
Publication of WO2006087736A1 publication Critical patent/WO2006087736A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
    • A01K73/00—Drawn nets
    • A01K73/02—Trawling nets
    • A01K73/04—Devices for spreading or positioning, e.g. control thereof
    • A01K73/05—Devices for spreading or positioning, e.g. control thereof for vertical sheering
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
    • A01K75/00—Accessories for fishing nets; Details of fishing nets, e.g. structure

Definitions

  • the invention relates to trawl nets for trawl fishing and in particular self-spreading trawl net technology.
  • the teachings of the above identified published PCT applications is used to create mesh bars having a plurality of cambered sections oriented and configured so that, when a trawl based on said mesh bars is towed through a body of water, the cambered sectioned mesh bars generate lift vectors mainly directed (i) normalized to the long axis of the cambered sectioned mesh bar, and (ii) away from one side or other of the plane of the netting panel generally formed by the cambered sectioned mesh bars.
  • the mesh bar When the cambered sectioned mesh bars are oriented in such a way that the generated lift vector is mainly directed outward, away from the axis of the trawl, the mesh bar has come to be known as, and is hereinafter referred to as, a "self-spreading mesh bar".
  • a netting panel includes cambered sectioned mesh bars, and the cambered sectioned mesh bars forming the netting panel mainly are “self-spreading mesh bars”, the netting panel has come to be known as, and is hereinafter referred to as, a "self-spreading netting panel".
  • the mesh bars in a mesh cell of a self-spreading netting panel are configured such that the handedness of the pitch (left- or right- handedness) of one mesh bar is in the opposite direction as its mating mesh bar, as it explained in greater detail in the above referenced applications, in particular WO 97/13407.
  • the opposite, e.g. parallel, mesh bars of any mesh cell act as mini-hydrofoils or wings in concert in operations.
  • Such opposite bars are characterized as having a common lay direction when viewed in an axially receding direction (either right-handed or left-handed lay) that is opposite to that associated with the other two mating (e.g. parallel) mesh bars in the mesh cell.
  • cambered sectioned mesh bars may be used in a trawl to form at least a front end of the trawl from the cambered sectioned mesh bars oriented in such a way that lift vectors generated by the cambered sectioned mesh bars mainly are directed outward, away from the center of the trawl (i.e. forming the trawl mainly from several "self-spreading mesh bars"), thus forming a "self-spreading trawl".
  • the above identified PCT applications teach that: a) the bottom panel of the front end of the trawl is optionally mainly formed from cambered sectioned mesh bars oriented so that their lift vectors mainly are directed inward, toward the center of the trawl, or so that their lift vectors are neutralized; and b) side panels of the front end of the trawl may include mesh bars forming netting panels having greater outwardly directed lift vectors than netting panels formed of mesh bars in the top or bottom panels of the front end of the trawl; and c) the back end of the trawl may be constructed of mesh not formed of cambered sectioned mesh bars, while the front end mainly includes mesh formed of cambered sectioned mesh bars oriented and configured in such a way that lift vectors formed by the cambered sectioned mesh bars during towing of the trawl through a body of water mainly are directed outwardly, away from the center of the trawl.
  • the present invention teaches a "self spreading trawl" having at least a top and bottom panel formed of “self spreading mesh bars”, the trawl including a front end and a back end, wherein at least the top panel of the front end comprises: ⁇
  • trawl mouth opening has a bettered horizontal opening dimension relative to vertical opening dimension, bettered uniformity of vertical opening dimension, both with concurrent better maintained back end opening.
  • the forward front end panel section is preferably formed of a netting panel including mesh that is mainly formed of mesh bars capable of generating less (including none) lift vectors directed outward, away from the center of the trawl when towed through the water environment than the mesh bars mainly forming the aft front end panel section, whereby the trawl shape includes a trawl mouth having a mouth vertical dimension that is better reduced in scale relative to a mouth horizontal dimension while concurrently conserving back end vertical dimensions.
  • the mesh forming the forward front end panel section of the trawl described supra mainly includes cambered sectioned mesh bars oriented so that lift vectors generated by the cambered sectioned mesh bars mainly neutralize each other, i.e. a "neutral netting panel section", whereby, the mesh panel forming the forward front end panel section generates less (including none) outwardly directed lift than does the mesh panel forming the aft front end panel section.
  • the mesh bars forming the mesh of the forward front end panel section of a trawl of the present invention either: a) mainly neutralize each by being oriented so that mesh bars generating lift vectors mainly directed outward, away from the center of the trawl (i.e. "self spreading mesh bars”) are mainly included in individual mesh with a similar number of cambered sectioned mesh bars generating lift vectors mainly directed inward, toward the center of the trawl (i.e.
  • self collapsing mesh bars or b) mainly are formed from conventional rope having insignificant lift vectors; and/or c) mainly are formed from rope having lead (or other heavier than water material) in the rope so as to reduce upwardly (toward the surface of the body of water) directed outwardly oriented lift vectors generated by the mesh bars.
  • the trawl of the present invention mainly is an all point taper trawl from the circumferential mesh row defining the fishing circle to the end of the trawl. That is, the trawl is constructed with no
  • point and bar taper in the trawl from the fishing circle row i.e. the first region of the trawl aft of the trawl's mouth, also defined as the first region of the trawl most proximal the trawl's mouth where there is a complete, 360 degree, envelope of netting forming the trawl
  • the all point taper of the front end is preferably formed of radial pattern mesh, as described in WO 03/081989.
  • Radial pattern mesh in a trawl indicates that the size of mesh cells is progressively reduced from front to back of the trawl through progressively shorter mesh bars. Thus, within an individual mesh cell of a radial pattern trawl (or radial pattern portion thereof) the two mesh bars nearer the mouth of the trawl 13 are longer than the two mesh ⁇
  • None of the known art has proposed a trawl where the front end of the trawl aft of the fishing circle is all point taper (or mainly all point taper) in combination with a back end that is all point taper (or mainly all point taper).
  • Fig. 1 shows a top plan view of the trawl 1 of the present invention showing the upper (or top) side of the trawl of the present invention having a front end 2 and a back end 3.
  • the distal end part of the back end 3, comprising the codend is not shown, i.e. the back end extends to a closed end conical or sac-like terminus referred to as the codend or brailer bag, to collect the catch.
  • the upper side of the trawl of the present invention includes top panel 4 having top panel forward front end panel section 5 and aft front end panel section 6.
  • Aft front end panel section 6 includes subsections 6a, 6b, 6c and 6d defining progressively smaller mesh sizes, respectively.
  • Back end 3 includes smaller mesh sizes than those forming subsections 6a - 6d
  • Aft front end panel sections 6a - 6d mainly include "self spreading mesh bars” 31 and 32, thus forming “self-spreading netting panels” 34, and preferably are formed entirely of "self- spreading mesh bars”. In this way, aft front end panel sections 6a - 6d serve to provide opening forces directly to and most proximal to back end 3 so as to better maintain the opening of back end 3 under field conditions, including heavy loading.
  • intersections between the above defined sections of the trawl need not be precisely defined by an abrubt or stepwise change in the mesh bar type and/or mesh size, and the ratio between the lengths of the sections can vary between different embodiments of the trawl of the invention.
  • the forward front end is about equal in widest width as the aft front end panel section.
  • the widest width of the forward front end panel section may be in the range between 50% and 800% of the widest width of the aft front end panel section.
  • top panel forward front end panel section 5 mainly is formed of neutralized non-self spreading mesh bars 21 and 22, forming a neutralized netting panel section as described supra, so as to form a "non-self spreading netting panel portion" 35.
  • selvedge mesh bars 33 are preferably of a larger diameter than mesh bars 21, 21, and also are preferably "self spreading mesh bars", so as to provide improved horizontal opening to the trawl mouth as well as to provide stability to the sides of the trawl, thus improving trawl mouth uniformity and symmetry of shape.
  • the trawl of the present invention includes a front end having a portion aft (toward the back of the trawl) of the fishing circle that mainly is constructed of "all point taper" netting panels in combination with a back end that mainly is constructed of "all point taper” netting panels.

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  • Life Sciences & Earth Sciences (AREA)
  • Environmental Sciences (AREA)
  • Animal Husbandry (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Marine Sciences & Fisheries (AREA)

Abstract

Chalut (1) doté d'au moins un panneau supérieur et un panneau inférieur, comprenant des mailles à côtés auto-extensibles, le chalut comprenant une extrémité avant (2) et une extrémité arrière (3), ou au moins le panneau supérieur (4) de l'extrémité avant comporte un tronçon arrière (6) de panneau d'extrémité avant et un tronçon avant (5) de panneau d'extrémité avant, le tronçon arrière (6) de panneau d'extrémité avant étant formé d'un panneau de filet auto-extensible et le tronçon avant (5) de panneau d'extrémité avant étant formé d'un panneau de filet présentant moins de portance dirigée vers l'extérieur que le panneau de filet formant le tronçon arrière (6) de panneau d'extrémité avant. Cette configuration améliore le facteur de forme de l'ouverture de la bouche du chalut, c'est-à-dire que l'ouverture horizontale est privilégiée par rapport à l'ouverture verticale, l'ouverture verticale étant plus uniforme, ce qui conduit à un meilleur maintien de l'ouverture de l'extrémité arrière du chalut.
PCT/IS2006/000004 2005-02-18 2006-02-17 Chalut large presentant des caracteristiques ameliorees d'ouverture de la bouche et de l'extremite arriere WO2006087736A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US65440305P 2005-02-18 2005-02-18
US60/654,403 2005-02-18

Publications (1)

Publication Number Publication Date
WO2006087736A1 true WO2006087736A1 (fr) 2006-08-24

Family

ID=36123571

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IS2006/000004 WO2006087736A1 (fr) 2005-02-18 2006-02-17 Chalut large presentant des caracteristiques ameliorees d'ouverture de la bouche et de l'extremite arriere

Country Status (1)

Country Link
WO (1) WO2006087736A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4521986A (en) * 1983-09-19 1985-06-11 Tatsumi Koga Net fabric for trawling
SU1355205A1 (ru) * 1986-07-04 1987-11-30 Научно-Производственное Объединение По Технике Промышленного Рыболовства Трал дл лова рыбы
WO2003081989A2 (fr) * 2002-03-22 2003-10-09 Candís ehf. Chaluts a auto-etalement comprenant une ouverture d'entree a rapport de forme eleve

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4521986A (en) * 1983-09-19 1985-06-11 Tatsumi Koga Net fabric for trawling
SU1355205A1 (ru) * 1986-07-04 1987-11-30 Научно-Производственное Объединение По Технике Промышленного Рыболовства Трал дл лова рыбы
WO2003081989A2 (fr) * 2002-03-22 2003-10-09 Candís ehf. Chaluts a auto-etalement comprenant une ouverture d'entree a rapport de forme eleve

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section PQ Week 198825, Derwent World Patents Index; Class P14, AN 1988-173737, XP002376833 *

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