U.S. patent application number 10/036992 was filed with the patent office on 2002-05-09 for trawl system cell design and methods.
Invention is credited to Perevoshchikov, Valentin G., Safwat, Sherif.
Application Number | 20020053157 10/036992 |
Document ID | / |
Family ID | 27357850 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020053157 |
Kind Code |
A1 |
Safwat, Sherif ; et
al. |
May 9, 2002 |
Trawl system cell design and methods
Abstract
A mesh cell construction which is systemized wherein opposite
mesh bars of the rectangularly shaped mesh cell have 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 remaining opposite mesh bars of such mesh cell.
In another aspect, when incorporated in a trawl (13), such cell
construction of the invention provides for improved shaping and
performance of the trawl (13) wherein the mesh cells of different
geometrical locations positioned relative to and about the
longitudinal axis of the trawl can be controlled such that
resulting trawl panels wings (25) act analogous to a series of
mini-wings capable of acting in concert in operation. Such
concerted action provides, when the trawl is in motion, outwardly
directed force vectors which significantly increase the trawl
volume and hence mouth (26) volume while simultaneously decreasing
drag.
Inventors: |
Safwat, Sherif; (Davis,
CA) ; Perevoshchikov, Valentin G.; (Kaliningrad,
RU) |
Correspondence
Address: |
A Professional Corporation
Post Office Box 64150
Sunnyvale
CA
94088-4150
US
|
Family ID: |
27357850 |
Appl. No.: |
10/036992 |
Filed: |
December 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10036992 |
Dec 29, 2001 |
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09051326 |
Jan 11, 1999 |
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09051326 |
Jan 11, 1999 |
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PCT/US96/16419 |
Oct 11, 1996 |
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60005287 |
Oct 13, 1995 |
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60013509 |
Mar 15, 1996 |
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60018069 |
May 21, 1996 |
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Current U.S.
Class: |
43/9.1 |
Current CPC
Class: |
A01K 73/02 20130101;
A01K 75/00 20130101 |
Class at
Publication: |
43/9.1 |
International
Class: |
A01K 073/02 |
Claims
What is claimed is:
1. A cell for use in a trawl system for generating a hydrofoil-like
effect during field operations for aiding in increasing a
performance characteristic thereof in a water-entrained
environment, comprising first and second cell bar means offset from
a central axis associated with a trawl system and having at least
one interconnecting connection therebetween, each of said first and
second cell bar means comprising a shaped hydrofoil means whereby
in field operations as said cell is propelled through a
water-entrained environment, leading and trailing edges are
established for each of said shaped hydrofoil means along with
separate pressure differentials that provide lift vectors relative
to said central axis to increase cell performance wherein said
leading edge for said first cell bar means when normalized to a
receding direction relative to said central axis, reside at a right
side of said first cell bar means as viewed in said receding
direction and wherein said leading edge of said second cell bar
means when normalized to said receding direction, reside along a
left side of said second bar means as viewed.
2. The cell of claim 1 wherein said trawl system is selected from a
group comprising a trawl, first and second tow lines, frontropes
and first and second bridles, and said central axis is individually
associated therewith and wherein said shaped hydrofoil means of
said first cell bar means includes at least first and second
strands positioned along a first axis of symmetry offset from said
central axis wherein at least one of which is of a left-hand,
loosely wound lay relative to said receding direction and said
central axis and wherein said shaped hydrofoil means of said second
cell bar means includes at least third and fourth strands in which
at least one of which is of a right-hand, loosely wound lay
relative to said receding direction and said central axis, said
first, second, third and fourth strands having a common origin at
said at least one interconnecting connection.
3. The cell of claim 2 in which said selected group of said trawl
system is said trawl and said central axis is symmetrical thereof
and wherein said cell performance comprises increasing trawl volume
relative to said central axis by said lift vectors.
4. The cell of claim 2 in which said selected group of said trawl
system is said first and second tow lines, said central axis is
central thereof and said at least one interconnecting connection
thereof is at a vessel or trawler at the surface of a body of water
and wherein said cell performance comprises increasing spreading
distance therebetween by said lift vectors, and in shallow waters,
decreasing diving vectors.
5. The cell of claim 2 in which said selected group of said trawl
system is said frontropes and said central axis is central thereof
and wherein said cell performance comprises increasing volume of a
trawl attached thereto by said lift vectors.
6. The cell of claim 2 in which said selected group of said trawl
system is said first and second bridles and said central axis is
central thereof and wherein said cell performance comprises
increasing spreading distance therebetween by said lift
vectors.
7. The cell of claim 2 wherein both said first and second strands
are both of a left-hand, loosely wound lay and are constructed to
wind uniformly with respect to said first axis of symmetry in said
receding direction relative to said central axis and wherein said
third and fourth strands are both of a right-hand, loosely wound
lay and wind uniformly with respect to said second axis of symmetry
in said receding direction relative to said central axis.
8. The cell of claim 7 in which said first and second strands are
each formed of synthetic or natural fibers or filaments and are
each internally twisted in a left-hand lay relative to said
receding direction, and in which said third and fourth strands are
each formed of synthetic or natural fibers or filaments and each
are internally twisted in a right-hand lay relative to said
receding direction.
9. The cell of claim 7 in which said strands are each formed of
internally braided synthetic or natural fibers or filaments.
10. The cell of claim 2 in which said first strand is provided with
an internal axis of symmetry coincident with said first axis of
symmetry and is positioned in an unwound state relative thereto,
said second strand being constructed to wind about said first
strand in uniform fashion to provide said left-hand loosely wound
lay and in which said third strand is provided with an internal
axis of symmetry coincident with said second axis of symmetry and
is positioned in an unwound state relative thereto, said fourth
strand being constructed to wind about said third strand to provide
said right-hand loosely wound lay.
11. The cell of claim 10 in which first and third strands are each
formed of synthetic or natural fibers or filaments internally
braided to form same; in which said second strand is formed of
synthetic or natural fibers or filaments internally twisted into a
left-hand lay relative to said receding direction, and in which
said fourth strand is formed of internal twisted synthetic or
natural fibers having a right-hand lay relative to said receding
direction.
12. The cell of claim 10 in which each strand is formed of
synthetic or natural fibers or filaments braided together to form
same.
13. The cell of claim 10 in which second and fourth strands are
each formed of synthetic or natural fibers or filaments internally
braided to form same; said second strand being constructed to wind
about said first strand in uniform fashion to provide said
left-hand loosely wound lay relative to said receding direction;
said fourth strand being constructed to wind about said third
strand in uniform fashion to provide said right-hand loosely wound
lay relative to said receding direction.
14. The cell of claim 13 in which said first and third strands are
each formed of internally twisted synthetic or natural fibers or
filaments; said internal twist of said first strand providing a
left-hand internal lay relative to said receding direction; said
internal twist of said third strand providing a right-hand internal
lay relative to said receding direction.
15. The cell of claim 7 in which said first and second strands
define turns in a pitch range of about 3d to 70d where d is the
diameter of at least the smaller of said strands and in which said
third and fourth strands define turns in a pitch range of about 3d
to 70d where d is the diameter of at least the smaller of said
strands.
16. The cell of claim 10 in which said second and fourth strands
define turns in a pitch range about 3d to 70d where d is the
diameter thereof.
17. The cell of claim 15 in which said pitch range is about 5 d to
40d.
18. The cell of claim 16 in which said pitch range is about 5 d to
40d.
19. The cell of claim 1 wherein said trawl system is selected from
a group comprising a trawl, first and second tow lines, frontropes
and first and second bridles, and said central axis is individually
associated therewith and wherein said shaped hydrofoil means of
said first cell bar means includes a first single strap having a
cross section selected by the group comprising a rectangular cross
section and a quasi-rectangular cross section and wherein said
shaped hydrofoil means of said second cell bar means also includes
a second single strap having a cross section selected by the group
comprising a rectangular cross section and a quasi-rectangular
cross section, said first and second straps having a common origin
at said at least one interconnecting connection.
20. The cell of claim 19 in which said selected group of said trawl
system is said trawl and said central axis is symmetrical thereof
and wherein said cell performance comprises increasing trawl volume
relative to said central axis by said lift vectors.
21. The cell of claim 19 in which said selected group of said trawl
system is said first and second tow lines and said central axis is
central thereof and wherein said cell performance comprises
increasing spreading distance therebetween by said lift
vectors.
22. The cell of claim 19 in which said selected group of said trawl
system is said frontropes and said central axis is central thereof
and wherein said cell performance comprises increasing volume of a
trawl attached thereto by said lift vectors.
23. The cell of claim 19 in which said selected group of said trawl
system is said first and second bridles and said central axis is
central thereof and wherein said cell performance comprises
increasing spreading distance therebetween by said lift
vectors.
24. The cell of claim 19 wherein said first single strap associated
with said first cell bar means is of a left-hand, loosely separated
lay relative to said receding direction and wherein said second
single strap associated with said second cell bar means is of a
right-hand, loosely separated lay along said receding
direction.
25. The cell of claim 24 in which said first single strap
associated with first cell bar means and said second single strap
associated with second cell bar means define turns in a pitch range
of about 3d to 70d where d is the mean width of said straps.
26. The cell of claim 25 in which pitch range is about 5d to 40d
where d is the mean width of said straps.
27. The cell of claim 3 wherein said first cell bar means comprises
a first pair of parallel mesh bars associated with a quadratic mesh
cell for use therewith and wherein said second cell bar means
comprises a second pair of parallel mesh bars also associated with
said mesh cell, said first and second pairs of mesh bars being
connecting by a plurality of connecting intersections including
said at least one interconnecting connection, said first pair of
parallel mesh bars each comprising first and second strands
positioned along a first axis of symmetry, at least one which being
of a left-hand, loosely wound lay relative to central axis, said
second pair of parallel mesh bars each comprising third and fourth
strands positioned along a second axis of symmetry, at least one of
which being of a right-hand, loosely wound lay relative to a said
central axis whereby said leading and trailing edges for said first
and second parallel mesh bars are established along with separate
pressure differentials that provide said lift vectors relative to
said central axis to increase volume of said trawl relative to said
central axis.
28. The cell of claim 27 wherein both said first and second strands
are both of a left-hand, loosely wound lay and are constructed to
wind uniformly with respect to said first axis of symmetry in said
receding direction and wherein said third and fourth strands are
both of a right-hand, loosely wound lay and wind uniformly with
respect to said second axis of symmetry in said receding
direction.
29. The cell of claim 28 in which said first and second strands are
each formed of synthetic or natural fibers or filaments and are
each internally twisted in a left-hand lay relative to said
receding direction, and in which said third and fourth strands are
each formed of synthetic or natural fibers or filaments and each
are internally twisted in a right-hand lay relative to said
receding direction.
30. The cell of claim 28 in which said strands are each itself
formed of internal braided synthetic or natural fibers or
filaments.
31. The cell of claim 27 in which said first strand is provided
with an internal axis of symmetry coincident with said first axis
of symmetry and is positioned in an unwound state relative thereto,
said second strand being constructed to wind about said first
strand in uniform fashion to provide said left-hand loosely wound
lay and in which said third strand is provided with an internal
axis of symmetry coincident with said second axis of symmetry and
is positioned in an unwound state relative thereto, said fourth
strand being constructed to wind about said third strand to provide
said right-hand loosely wound lay.
32. The cell of claim 31 in which first and third strands are each
formed of synthetic or natural fibers or filaments internally
braided to form same; in which said second strand is formed of
synthetic or natural fibers or filaments internally twisted into a
left-hand lay relative to said receding direction; and in which
said fourth strand is formed of internal twisted synthetic or
natural fibers having a right-hand lay relative to said receding
direction.
33. The cell of claim 31 in which each strand is formed of
synthetic or natural fibers or filaments braided together to form
same.
34. The cell of claim 31 in which second and fourth strands are
each formed of synthetic or natural fibers or filaments internally
braided to form same; said second strand being constructed to wind
about said first strand in uniform fashion to provide said
left-hand loosely wound lay relative to said receding direction;
said fourth strand being constructed to wind about said third
strand in uniform fashion to provide said right-hand loosely wound
lay relative to said receding direction.
35. The cell of claim 34 in which said first and third strands are
each formed of internally twisted synthetic or natural fibers or
filaments; said internal twist of said first strand providing a
right-hand internal lay relative to said receding direction; said
internal twist of said third strand providing a left-hand internal
lay relative to said receding direction.
36. The cell of claim 28 in which said first and second strands
define turns in a pitch range of about 3d to 70d where d is the
diameter of at least the larger of said strands and in which said
third and fourth strands of said second cell bar means define turns
in a pitch range of about 3d to 70d where d is the diameter of at
least the smaller of said strands.
37. The cell of claim 36 in which said second and fourth strands
define turns in a pitch range about 3d to 70d where d is the
diameter thereof.
38. The cell of claim 36 in which said pitch range is about 5d to
40d where d is the diameter of at least the smaller of said
strands.
39. The cell of claim 37 in which said pitch range is about 5d to
40d where d is the diameter thereof.
40. The cell of claim 3 wherein said first cell bar means comprises
a first pair of parallel mesh bars that is associated with a mesh
cell for aiding in constructing said trawl and wherein said second
cell bar means comprises a second pair of parallel mesh bars also
associated with said mesh cell, said first and second pairs of
parallel mesh bars being connecting by a plurality of connecting
intersections including said at least one interconnecting
connection, said first pair of parallel mesh bars each comprising a
first single strap having a cross section selected by the group
comprising a rectangular cross section and a quasi-rectangular
cross section, said second pair of parallel mesh bars each
comprising a second single strap having a cross section selected by
the group comprising a rectangular cross section and a
quasi-rectangular cross section whereby leading and trailing edges
for said first and second parallel mesh bars are established along
with separate pressure differentials that provide lift vectors
relative to said central axis to increase volume of said net, trawl
or the like.
41. The cell of claim 40 wherein said first single strap associated
with said first pair of parallel mesh bars is of a left-hand,
loosely separated twisting lay and wherein said second single strap
associated with said second pair of parallel mesh bars is of a
right-hand, loosely separated twisting lay.
42. The cell of claim 41 in which said first and second single
straps define turns in a pitch range of about 3d to 70d where d is
the mean width of said strap.
43. The cell of claim 42 in which said pitch range is about 5d to
40d.
44. A mesh cell used in a trawl, net or the like for generating a
hydrofoil-like effect during field operations for aiding in
capturing marine life in a water-entrained environment, comprising
first and second pairs of mesh bars offset from a central axis
having interconnecting connections, said first pair of mesh bars
including first and second mesh bars oriented substantially
parallel to each other, each of said first and second mesh bars
being constructed of at least two strands positioned relative to a
first axis of symmetry, at least one of said at least two strands
being of a left-hand, loosely wound lay relative to a receding
direction normalized to said central axis, said second pair of mesh
bars including third and fourth mesh bars oriented substantially
parallel to each other but not parallel with said first pair of
mesh bars, each of said third and fourth mesh bars being
constructed of at least two strands positioned relative to a second
axis of symmetry, at least one of said at least two strands being
of a right-hand, loosely wound lay relative to said receding
direction whereby in field operations as said mesh cell is
propelled through a water-entrained environment, leading and
trailing edges are established for said first and second pairs of
mesh bars along with a composite pressure differential therebetween
so that an outwardly extending lift vector relative to said central
axis is easily and accurately generated to increase mesh cell
volume.
45. The mesh cell of claim 44 wherein said leading edge of each of
said first and second mesh bars of said first pair when normalized
to said receding direction, reside at a right side of each of such
bars as viewed in said receding direction and wherein said leading
edge of each of said third and fourth mesh bars of said second pair
when normalized to said receding direction, reside along a left
side thereof each as viewed.
46. The mesh cell of claim 44 wherein said at least two strands of
each of said first pair of mesh bars, include a first and a second
strand both of which being of a left-hand, loosely wound twisting
lay relative to said receding direction and are constructed to wind
uniformly with respect to said first axis of symmetry in said
receding direction therealong and wherein said at least two strands
of each of said second pair of mesh bars, include a third and a
fourth strand both of which being of a right-hand, loosely wound
twisting lay relative to said receding direction and wind uniformly
with respect to said second axis of symmetry in said receding
direction.
47. The mesh cell of claim 44 wherein said at least two strands of
each of said first pair of mesh bars, include at least a first
strand and a second strand, said first strand having an internal
axis of symmetry coincident with said first axis of symmetry and is
positioned in an unwound state relative thereto, said second strand
winding about said first strand in uniform fashion to provide said
left-hand loosely wound lay relative to said receding direction,
and wherein said at least two strands of each of said second pair
of mesh bars, include at least a third strand and a fourth strand,
said third strand having an internal axis of symmetry coincident
with said second axis of symmetry and is positioned in an unwound
state relative thereto, said fourth strand winding about said third
strand in uniform fashion to provide said right-hand loosely wound
lay relative to said receding direction.
48. The mesh cell of claim 47 wherein said at least two strands of
each of said first pair of mesh bars includes a first additional
strand and wherein said at least two strands of each of said second
pair of mesh bars includes a second additional strand, said first
additional strand also winding about said first strand in uniform
fashion in a left-hand lay relative to said receding direction,
said second additional strand also winding about said third strand
in uniform fashion in a right-hand lay relative to said receding
direction.
49. The mesh cell of claim 48 wherein said second strand and said
first additional strand define substantially similar turns each to
the other but in which said turns of one is diametrically
positioned about said first strand relative to the other and
wherein said fourth strand and said second additional strand define
substantially similar turns each to the other but in which said
turns of one is diametrically positioned about said third strand
relative to the other.
50. The mesh cell of claim 46 in which said first and second
strands define turns in a pitch range of about 3d to 70d where d is
the diameter of at least the smaller of said strands and in which
said third and fourth strands define turns in a pitch range of
about 3d to 70d where d is the diameter of at least the smaller of
said strands.
51. The cell of claim 47 in which said second and fourth strands
define turns in a pitch range about 3d to 70d where d is the
diameter thereof.
52. The cell of claim 50 in which said pitch range is about 5d to
40d.
53. The cell of claim 51 in which said pitch range is about 5d to
40d.
54. A mesh cell used in a trawl, net or the like for generating a
composite pressure differential during field operations to increase
mesh cell volume for aiding in capturing marine life in a
water-entrained environment, comprising first and second pairs of
mesh bars offset from a central axis having connecting
intersections, said first pair of mesh bars comprising first and
second straps oriented substantially parallel to each other, said
second pair of mesh bars comprising third and fourth straps
oriented substantially parallel to each other but not parallel to
said first and second straps, said first, second, third and fourth
straps each having a cross section selected from the group
comprising a rectangular cross section and a quasi-rectangular
cross section whereby in field operations as said mesh cell is
propelled through a water-entrained environment, leading and
trailing edges are established therefor along with a composite
pressure differential therebetween so that an outwardly extending
lift vector relative to said central axis is easily and accurately
generated to increase mesh cell volume.
55. The mesh cell of claim 54 wherein said leading edge of said
first and second straps of said first pair when normalized to a
receding direction along each strap, reside at a right side thereof
as viewed in said receding direction and wherein said leading edge
of said third and fourth straps of said second pair when normalized
to a receding direction along each strap, reside along a left side
thereof as viewed.
56. The mesh cell of claim 55 wherein said first and second straps
associated with said first pair of mesh bars are of a left-hand,
loosely separated twisting lay relative to said receding direction
and wherein said third and fourth straps associated with said
second pair of mesh bars are of a right-hand, loosely separated
twisting lay relative to said receding direction.
57. The mesh cell of claim 56 in which said first, second, third
and fourth straps of said first and second pairs of mesh bars each
defines turns in a pitch range of about 3d to 70d where d is the
mean width of said straps.
58. The mesh cell of claim 57 in which pitch range is about 5d to
40d where d is the mean width of said straps.
59. The mesh cell of claim 55 in which each of said first, second,
third and fourth straps have a quasi-rectangular cross section
include cambered long side surfaces and rounded short side surfaces
in which said cambered long side surfaces are most exterior
relative to said central axis.
60. The mesh cell of claim 59 in which said each of said first,
second, third and fourth straps include an internal cavity interior
of said long and short side surfaces and a plurality of strands
residing in said internal cavity.
61. The mesh cell of claim 60 in said plurality of strands residing
in each of said internal cavities, comprise two in number of equal
diameter.
62. The mesh cell of claim 60 in said plurality of strands residing
in each of said internal cavities, comprise three in number of
equal diameter.
63. A mesh cell used in a trawl, net or the like for generating a
hydrofoil-like effect during field operations for aiding in
capturing marine life in a water-entrained environment, comprising
first and second pairs of mesh bars offset from a central axis
having connecting intersections, said first pair of mesh bars
including first and second mesh bars oriented substantially
parallel to each other, each of said first and second mesh bars
being positioned relative to a first axis of symmetry and
constructed of at least two strands at least one of which being of
a left-hand, loosely wound lay relative a receding direction
normalized to said central axis and defining turns in a range of 3d
to 70d where d is the diameter of said at least one strand, said
second pair of mesh bars including third and fourth mesh bars
oriented substantially parallel to each other but not parallel with
said first pair of mesh bars, each of said third and fourth mesh
bars being positioned relative to a second axis of symmetry and
constructed of at least two strands at least one of which being of
a right-hand, loosely wound lay relative said receding direction
normalized to said central axis and also defining turns in a range
of 3d to 70d where d is the diameter of said at least one strand
whereby in field operations as said mesh cell is propelled through
a water-entrained environment, leading and trailing edges are
established for said first and second pairs of mesh bars along with
a composite pressure differential therebetween so that an outwardly
extending lift vector relative to said central axis is easily and
accurately generated to increase mesh cell volume.
64. The mesh cell of claim 63 wherein said leading edge of each
mesh bar of said first pair relative to said receding direction
normalized to said central axis, reside at a right side thereof as
viewed in said receding direction and wherein said leading edge of
each mesh bar of said second pair when normalized to a receding
direction, reside along a left side thereof as viewed.
65. The mesh cell of claim 64 in which said two strands of each of
said first and second mesh bars of said first pair, wind uniformly
about said first axis of symmetry, and in which said two strands of
each of said third and fourth mesh bars also both wind uniformly
about said second axis of symmetry.
66. The cell of claim 64 in which the other strand of each of said
first and second mesh bars is provided with an internal axis of
symmetry coincident with said first axis of symmetry and is
positioned in an unwound state relative thereto, said at least one
strand being constructed to wind about said other strand in uniform
fashion to provide said left-hand loosely wound lay and in which
the other strand of each of said third and fourth mesh bars is
provided with an internal axis of symmetry coincident with said
second axis of symmetry and is positioned in an unwound state
relative thereto, said at least one strand being constructed to
wind about said other strand in uniform fashion to provide said
right-hand loosely wound lay.
67. A mesh cell used in a trawl, net or the like for generating a
composite pressure differential during field operations to increase
mesh cell volume for aiding in capturing marine life in a
water-entrained environment, comprising a central axis, at least
three mesh bars offset from said central axis forming sides and a
series of associated intersections oriented in space defining a
pre-selected cross section in a common longitudinal plane also
offset from said central axis, a transverse working plane normal to
said longitudinal plane that passes through at least two
intersections between a pair of mesh bars, each pair of mesh bars
being formed of first and second mesh bars of oppositely but
loosely wound strands whereby in field operations as said cell is
propelled through a water-entrained environment, leading and
trailing edges are established for said first and second mesh bars
along with a composite pressure differential therebetween so that
an outwardly extending lift vector relative to said central axis is
easily and accurately generated to increase mesh cell volume.
68. The mesh cell of claim 67 in which said strands of said first
mesh bar are at least two in number in which at least one thereof
is of a left-hand, loosely wound lay when view in a receding
direction relative to said central axis and wherein strands of said
second mesh bar are at least two in number wherein at least one
thereof is of right-hand, loosely wound lay when viewed in said
receding direction wherein said leading edge of said first mesh bar
when normalized to said receding direction, reside at a right side
of each such bar as viewed in said receding direction and wherein
said leading edge of second mesh bar of said pair when normalized
to a receding direction, reside along a left side thereof as
viewed.
69. The mesh cell of claim 68 in which said at least one strand of
said first and second mesh bars define turns in a pitch range of
about 3d to 70d where d is the diameter of said at least one
strand.
70. The mesh cell of claim 69 in which both strands uniformly wind
about each other to define said turns.
71. The mesh cell of claim 67 in which said cross section is
rectangular.
72. The mesh cell of claim 67 in which cross section is
triangular.
73. The mesh cell of claim 67 in which cross section is
hexagonal.
74. The mesh cell of claim 67 in which said transverse working
plane bisects two intersections of said mesh bars to form an
imaginary base and forms a pair of half mesh cells each consisting
of a pair of oppositely wound mesh bars depending from an
intersection offset from said base.
75. A mesh cell used in a trawl, net or the like for generating a
composite pressure differential during field operations to increase
mesh cell volume for aiding in capturing marine life in a
water-entrained environment, comprising a central axis, at least
three mesh bars offset from said central axis forming sides and a
series of associated intersections oriented in space defining a
pre-selected cross section in a common longitudinal plane also
offset from said central axis, a transverse working plane normal to
said longitudinal plane that passes through at least two
intersections between said first and second mesh bars, each mesh
bar defining a single strap defining leading and trailing edges
during field operations, said single strap defining said first mesh
bar being twisted in a first direction about its longitudinal axis
of symmetry thereof, said single strap defining said second mesh
bar being twisted a second direction opposite of said first
direction about its longitudinal axis of symmetry whereby in field
operations as said mesh cell is propelled through a water-entrained
environment, a composite pressure differential associated with said
leading and trailing edges is established for said first and second
mesh bars so that an outwardly extending lift vector relative to
said central axis is easily and accurately generated to increase
mesh cell volume.
76. The mesh cell of claim 75 wherein said leading edge of said
first mesh bar when normalized to a receding direction relative to
said central axis, reside at a right side thereof as viewed in said
receding direction and wherein said leading edge of said second
mesh bar mesh bar when normalized to said receding direction
therealong, reside along a left side thereof as viewed.
77. The mesh cell of claim 76 in which said first direction of
twist associated with said single strap constituting said first
mesh bar is of a left-hand lay as viewed in said receding direction
and wherein said second direction of twist associated with said
single strap comprising said second mesh bar is of a right-hand lay
as viewed in said receding direction.
78. The mesh cell of claim 77 in which said left-hand and
right-hand lay directions of twist associated with said straps
comprising said first and second mesh bars, respectively, define
turns in a pitch range of about 3d to 70d where d is the mean width
of said strap.
79. The mesh cell of claim 78 in which said cross section is
rectangular.
80. The mesh cell of claim 78 in which cross section is
triangular.
81. The mesh cell of claim 78 in which cross section is
hexagonal.
82. The mesh cell of claim 78 in which said pitch range of said is
about 5d to 40d.
83. A towline interconnecting a trawl, net or the like with a
vessel at the surface of a body of water for generating a
hydrofoil-like effect during field operations for aiding in
increasing a performance characteristic thereof, comprising first
and second cell bar means offset from a central axis and having at
least one interconnecting intersection therebetween that includes a
portion of a vessel at the surface of body of water, each of said
first and second cell bar means comprising a shaped hydrofoil means
whereby in field operations as said cell is propelled through a
body of water, leading and trailing edges are established for each
of said shaped hydrofoil means along with separate pressure
differentials that provide lift vectors relative to said central
axis to increase towline performance wherein said leading edge for
said first cell bar means when normalized to a receding direction
relative to said central axis, reside at a right side of said first
cell bar means as viewed in said receding direction and wherein
said leading edge of said second cell bar means when normalized to
said receding direction, reside along a left side of said second
bar means as viewed.
84. The towline of claim 83 wherein said shaped hydrofoil means of
said first cell bar means includes at least first and second
strands positioned along a first axis of symmetry in which at least
one strand thereof is of a left-hand, loosely wound lay relative to
said receding direction and wherein said shaped hydrofoil means of
said second cell bar includes at least third and fourth strands in
which one strand thereof is of a right-hand, loosely wound lay
relative to said receding direction.
85. The towline of claim 84 in which said at least one strand of
said first and second strands defines turns in a pitch range of
about 3d to 70d where d is the diameter of said one strand.
86. The towline of claim 85 in which pitch range is about 5d to 40d
where d is the diameter of said one strand.
87. The towline of claim 83 wherein said shaped hydrofoil means of
said first cell bar means includes a first single strap having a
cross section selected by the group comprising a rectangular cross
section and a quasi-rectangular cross section and wherein said
shaped hydrofoil means of said second cell bar means also includes
a second single strap having a cross section selected by the group
comprising a rectangular cross section and a quasi-rectangular
cross section.
88. The towline of claim 87 wherein said first single strap
associated with said first cell bar means is of a left-hand,
loosely separated lay relative to said receding direction and
wherein said second single strap associated with said second cell
bar means is of a right-hand, loosely separated lay relative to
said receding direction.
89. The towline of claim 88 in which said first single strap
associated with first cell bar means and said second single strap
associated with second cell bar means define turns in a pitch range
of about 3d to 70d where d is the mean width of said straps.
90. The towline of claim 89 in which pitch range is about 5d to 40d
where d is the mean width of said straps.
91. Bridle line means interconnecting a towline selected from one
of a port and starboard towline connected to a trawl, net or the
like for generating a hydrofoil-like effect during field operations
for aiding in increasing a performance characteristic thereof,
comprising first and second cell bar means offset from a central
axis and defining an intersection with each other and with said
selected towline at a location below the surface of a body of
water, each of said first and second cell bar means comprising a
shaped hydrofoil means whereby in field operations as said cell is
propelled through said body of water, leading and trailing edges
are established for each of said shaped hydrofoil means along with
separate pressure differentials that provide lift vectors relative
to said central axis to increase volume of a trawl, net or the like
connect connected to said bridle line means wherein said leading
edge for said first cell bar means when normalized to a receding
direction relative to said central axis, reside at a right side of
said first cell bar means as viewed in said receding direction and
wherein said leading edge of said second cell bar means when
normalized to said receding, reside along a left side of said
second bar means as viewed.
92. The bridle line means of claim 91 wherein said shaped hydrofoil
means of said first cell bar means includes at least first and
second strands positioned relative to a first axis of symmetry in
which at least one strand thereof is of a left-hand, loosely wound
lay relative to said receding direction and wherein said shaped
hydrofoil means of said second cell bar includes at least third and
fourth strands positioned relative to a second axis of symmetry in
which at least one strand thereof is of a right-hand, loosely wound
lay relative to said receding direction.
93. The bridle line means of claim 92 in which said at least one
strand of said first and second strands and of said third and
fourth strands define turns in a pitch range of about 3d to 70d
where d is the diameter of said one strand.
94. The bridle line means of claim 93 in which said pitch range of
about 3d to 70d applies to said first, second, third and fourth
strands individually where d is the diameter of the smaller of any
one strand.
95. The bridle line means of claim 94 in which pitch range is about
5d to 40d.
96. The bridle line means of claim 93 in which pitch range is about
5d to 40d.
97. The bridle line means of claim 91 wherein said shaped hydrofoil
means of said first cell bar means includes a first single strap
having a cross section selected by the group comprising a
rectangular cross section and a quasi-rectangular cross section and
wherein said shaped hydrofoil means of said second cell bar means
includes a second single strap having a cross section selected by
the group comprising a rectangular cross section and a
quasi-rectangular cross section.
98. The bridle line means of claim 97 wherein said first single
strap associated with said first cell bar means is of a left-hand,
loosely separated lay relative to said receding direction and
wherein said second single strap associated with said second cell
bar means is of a right-hand, loosely separated lay relative to
said receding direction.
99. The bridle line means of claim 98 in which said first single
strap associated with first cell bar means and said second single
strap associated with second cell bar means define turns in a pitch
range of about 3d to 70d where d is the mean width of said
strap.
100. The bridle line means of claim 99 in which pitch range is
about 5d to 40d where d is the mean width of said strap.
101. Frontrope means interconnecting one or more bridle lines
associated with a preselected tow line selected from one of a port
and starboard towline connected to a trawl, net or the like for
generating a hydrofoil-like effect during field operations for
aiding in increasing a performance characteristic thereof,
comprising first and second cell bar means offset from a central
axis and defining an intersection with each other, said
intersection being positioned at a location below the surface of a
body of water, each of said first and second cell bar means
comprising a shaped hydrofoil means whereby in field operations as
said cell is propelled through said body of water, leading and
trailing edges are established for each of said shaped hydrofoil
means along with separate pressure differentials that provide lift
vectors relative to said central axis to increase volume of a
trawl, net or the like connected to said breast line means wherein
said leading edge for said first cell bar means when normalized to
a receding direction relative to said central axis, reside at a
right side of said first cell bar means as viewed in said receding
direction and wherein said leading edge of said second cell bar
means when normalized to said receding direction, reside along a
left side of said second bar means as viewed.
102. The frontrope means of claim 101 wherein said shaped hydrofoil
means of said first cell bar means includes at least first and
second strands positioned relative to a first axis of symmetry and
in which at least one strand thereof is of a left-hand, loosely
wound lay relative to said receding direction and wherein said
shaped hydrofoil means of said second cell bar includes at least
third and fourth strands positioned relative to a second axis of
symmetry in which at least one strand thereof is of a right-hand,
loosely wound lay relative to said receding direction.
103. The frontrope means of claim 102 in which said at least one
strand of said first and second strands and of said third and
fourth strands define turns in a pitch range of about 3d to 70d
where d is the diameter of said one strand.
104. The frontrope means of claim 103 in which said pitch range of
about 3d to 70d applies to said first, second, third and fourth
strands individually where d is the diameter of the smaller of any
strand.
105. The frontrope means of claim 103 in which pitch range is about
5d to 40d where d is the diameter of said one strand.
106. The frontrope means of claim 104 in which pitch range is about
5d to 40d where d is the diameter of the smaller of any strand.
107. The frontrope means of claim 101 wherein said shaped hydrofoil
means of said first cell bar means includes a first single strap
having a cross section selected by the group comprising a
rectangular cross section and a quasi-rectangular cross section and
wherein said shaped hydrofoil means of said second cell bar means
also includes a second single strap having a cross section selected
by the group comprising a rectangular cross section and a
quasi-rectangular cross section.
108. The frontrope means of claim 107 wherein said first single
strap associated with said first cell bar means is of a left-hand,
loosely separated lay relative to said receding direction and
wherein said second single strap associated with said second cell
bar means is of a right-hand, loosely separated lay along said
receding direction.
109. The frontrope means of claim 108 in which said first single
strap associated with first cell bar means and said second single
strap associated with second cell bar means define turns in a pitch
range of about 3d to 70d where d is the mean width of said
strap.
110. The frontrope means of claim 109 in which pitch range is about
5d to 40d where d is the mean width of said straps.
111. A method of using a cell associated with a trawl system for
generating a hydrofoil-like effect during field operations for
aiding in increasing a performance characteristic thereof in a
water-entrained environment, comprising the steps of: (i) from a
vessel positioned at the surface of a body of water, deploying
first and second cell bar means of a trawl system below the surface
of the body of water wherein a central axis offset from the first
and second cell bar means is established and the first and second
cell bar means have at least one interconnecting connection
therebetween, (ii) establishing positional and directional
integrity between the shaped hydrofoil means associated with each
of the first and second cell bar relative to the central axis, and
(ii) propelling the shaped hydrofoil means of each of the first and
second cell bar means whereby leading and trailing edges are
established therefor along with separate pressure differentials
that provide lift vectors relative to the central axis to increase
cell performance wherein said leading edge for the first cell bar
means when normalized to a receding direction relative to the
central axis, always resides at a right side of the first cell bar
means as viewed in the receding direction and wherein the leading
edge of the second cell bar means when normalized to the same
receding direction, reside along a left side thereof as viewed.
112. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a tow line selected from one of a port and
starboard tow line and the at least one interconnecting connection
therebetween is established at the vessel itself, in which step
(ii) includes positioning first and second strands comprising the
hydrofoil means of the first cell bar means so that at least one
strand thereof is positioned along a first axis of symmetry offset
from the central axis wherein at least one of which is of a
left-hand, loosely wound twisting lay relative to a receding
direction established relative to the central axis and positioning
third and fourth strands comprising the said shaped hydrofoil means
of said second cell bar along a second axis of symmetry so that at
least one of which is of a right-hand, loosely wound twisting lay
relative to the receding direction and the central axis; and in
which step (iii) includes the substep of increasing spread between
the port and starboard tow lines relative to the central axis to
gain increased cell performance.
113. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a port and starboard tow line, respectively and the
at least one interconnecting connection therebetween is established
at the vessel itself; in which step (ii) includes positioning a
first strap comprising the hydrofoil means of the first cell bar
means so that the same is positioned along a first axis of symmetry
offset from the central axis wherein the first strap is of a
left-hand, loosely wound lay relative to a receding direction
established relative to the central axis and positioning a second
strap comprising the shaped hydrofoil means of the second cell bar
along a second axis of symmetry wherein the second strap is of a
right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (iii) includes the substep
of increasing spread between the port and starboard tow lines
relative to the central axis to gain increased cell
performance.
114. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a trawl, the central axis being longitudinally
symmetrical of the trawl and the at least one interconnecting
connection being established below the surface of the body of
water; in which step (ii) includes positioning first and second
strands comprising the hydrofoil means of the first cell bar means
so that at least one strand thereof is positioned along a first
axis of symmetry offset from the central axis wherein at least one
of which is of a left-hand, loosely wound lay relative to a
receding direction established relative to the central axis, as
well as positioning third and fourth strands comprising the shaped
hydrofoil means of said second cell bar along a second axis of
symmetry so that at least one of which is of a right-hand, loosely
wound lay relative to the receding direction and the central axis;
and in which step (iii) includes the substep of increasing volume
of the trawl relative the central axis by the creation of the lift
vectors to gain increased cell performance.
115. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a trawl, the central axis being longitudinally
symmetrical with the trawl and the at least one interconnecting
connection therebetween being established below the surface of the
body of water, in which step (ii) includes positioning a first
strap comprising the hydrofoil means of the first cell bar means so
that the same is positioned along a first axis of symmetry offset
from the central axis wherein the first strap is of a left-hand,
loosely wound lay relative to a receding direction established
relative to the central axis as well as positioning a second strap
comprising the shaped hydrofoil means of the second cell bar along
a second axis of symmetry offset from the central axis wherein the
second strap is of a right-hand, loosely wound lay relative to the
receding direction and the central axis; and in which step (iii)
includes the substep of increasing volume of the trawl relative to
the central axis by the creation the lift vectors to gain increased
cell performance.
116. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a frontrope, the central axis being longitudinally
symmetrical of a trawl to which the frontrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water; in which step (ii) includes
positioning first and second strands comprising the hydrofoil means
of the first cell bar means so that at least one strand thereof is
positioned along a first axis of symmetry offset from the central
axis wherein at least one of which is of a left-hand, loosely wound
lay relative to a receding direction established relative to the
central axis, as well as positioning third and fourth strands
comprising the shaped hydrofoil means of said second cell bar along
a second axis of symmetry so that at least one of which is of a
right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (ii) includes the substep
of increasing volume of the trawl relative the central axis by the
creation of the lift vectors due to the frontrope to gain increased
cell performance.
117. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a frontrope, the central axis being longitudinally
symmetrical of a trawl to which the frontrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water, in which step (ii) includes
positioning a first strap comprising the hydrofoil means of the
first cell bar means so that the same is positioned along a first
axis of symmetry offset from the central axis wherein the first
strap is of a left-hand, loosely wound lay relative to a receding
direction established relative to the central axis as well as
positioning a second strap comprising the shaped hydrofoil means of
the second cell bar along a second axis of symmetry offset from the
central axis wherein the second strap is of a right-hand, loosely
wound lay relative to the receding direction and the central axis;
and in which step (iii) includes the substep of increasing volume
of the trawl relative to the central axis by the creation the lift
vectors due to the frontrope to gain increased cell
performance.
118. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with one of a pair of port and starboard bridles, the
central axis being longitudinally symmetrical of a trawl to which
the bridles attach and the at least one interconnecting connection
therebetween being established below the surface of the body of
water; in which step (ii) includes positioning first and second
strands comprising the hydrofoil means of the first cell bar means
so that at least one stand thereof is positioned along a first axis
of symmetry offset from the central axis wherein at least one of
which is of a left-hand, loosely wound lay relative to a receding
direction established relative to the central axis, as well as
positioning third and fourth strands comprising the shaped
hydrofoil means of said second cell bar along a second axis of
symmetry so that at least one of which is of a right-hand, loosely
wound lay relative to the receding direction and the central axis;
and in which step (iii) includes the substep of increasing volume
of the trawl relative the central axis by the creation of the lift
vectors due to the selected pair of bridles to gain increased cell
performance.
119. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with one of a pair of port and starboard bridles, the
central axis being longitudinally symmetrical of a trawl to which
the bridles attach and the at least one interconnecting connection
therebetween being established below the surface of the body of
water; in which step (ii) includes positioning a first strap
comprising the hydrofoil means of the first cell bar means so that
the same is positioned along a first axis of symmetry offset from
the central axis wherein the first strap is of a left-hand, loosely
wound lay relative to a receding direction established relative to
the central axis as well as positioning a second strap comprising
the shaped hydrofoil means of the second cell bar along a second
axis of symmetry offset from the central axis wherein the second
strap is of a right-hand, loosely wound lay relative to the
receding direction and the central axis; and in which step (iii)
includes the substep of increasing volume of the trawl relative to
the central axis by the creation the lift vectors due to the
selected pair of bridles to gain increased cell performance.
120. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a headrope, the central axis being longitudinally
symmetrical of a trawl to which the headrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water; in which step (ii) includes
positioning first and second strands comprising the hydrofoil means
of the first cell bar means so that at least one strand thereof is
positioned along a first axis of symmetry offset from the central
axis wherein at least one of which is of a left-hand, loosely wound
lay relative to a receding direction established relative to the
central axis, as well as positioning third and fourth strands
comprising the shaped hydrofoil means of said second cell bar means
along a second axis of symmetry so that at least one of which is of
a right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (iii) includes the substep
of increasing volume of the trawl relative the central axis by the
creation of the lift vectors due to the headrope to gain increased
cell performance.
121. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a headrope, the central axis being longitudinally
symmetrical of a trawl to which the headrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water, in which step (ii) includes
positioning a first strap comprising the hydrofoil means of the
first cell bar means so that the same is positioned along a first
axis of symmetry offset from the central axis wherein the first
strap is of a left-hand, loosely wound lay relative to a receding
direction established relative to the central axis as well as
positioning a second strap comprising the shaped hydrofoil means of
the second cell bar means along a second axis of symmetry offset
from the central axis wherein the second strap is of a right-hand,
loosely wound lay relative to the receding direction and the
central axis; and in which step (iii) includes the substep of
increasing volume of the trawl relative to the central axis by the
creation the lift vectors due to the headrope to gain increased
cell performance.
122. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a footrope, the central axis being longitudinally
symmetrical of a trawl to which the footrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water, in which step (ii) includes
positioning first and second strands comprising the hydrofoil means
of the first cell bar means so that at least one strand thereof is
positioned along a first axis of symmetry offset from the central
axis wherein at least one of which is of a left-hand, loosely wound
lay relative to a receding direction established relative to the
central axis, as well as positioning third and fourth strands
comprising the shaped hydrofoil means of said second cell bar means
along a second axis of symmetry so that at least one of which is of
a right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (ii) includes the substep
of increasing volume of the trawl relative the central axis by the
creation of the lift vectors due to the footrope to gain increased
cell performance.
123. The method of claim 111 in which step (i) being further
characterized by the first and second cell bar means being
associated with a footrope, the central axis being longitudinally
symmetrical of a trawl to which the footrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water, in which step (i) includes
positioning a first strap comprising the hydrofoil means of the
first cell bar means so that the same is positioned along a first
axis of symmetry offset from the central axis wherein the first
strap is of a left-hand, loosely wound lay relative to a receding
direction established relative to the central axis as well as
positioning a second strap comprising the shaped hydrofoil means of
the second cell bar means along a second axis of symmetry offset
from the central axis wherein the second strap is of a right-hand,
loosely wound lay relative to the receding direction and the
central axis; and in which step (iii) includes the substep of
increasing volume of the trawl relative to the central axis by the
creation the lift vectors due to the footrope to gain increased
cell performance.
Description
[0001] In one aspect, the invention relates to mesh cell
construction for trawls that can be triangular, rectangular and/or
hexagonal in cross section (where such rectangular configurations
include square cells) and is associated with at least three and
preferably four cell (or more) bars in a common plane, with the
length of each bar being measured between a pair of normalized
transverse, quasi-transverse, longitudinal or quasi-longitudinal
spaced-apart knots or equivalent couplers. In accordance with the
invention, a pair of half mesh bars of each cell are constructed so
as to fan out from a common knot or coupler (of the four knots or
couplers associated with each quadratic mesh cell). Each mesh bar
of such pair is constructed to provide hydrofoil-like
characteristics in field operations. Each mesh bar comprises two
(or three of more) strands each comprised of filamented synthetic
material such as plastic or of a naturally occurring substance,
each strand being the product of a conventional manufacturing
process. In accordance with the invention, such the strands are
constructed to be loosely twisted about a longitudinal axis of
symmetry in a direction opposite (not the same) as its mating mesh
bar. In addition, the pitch of the twist is controlled wherein each
mesh bar defines a range of pitch value, say from 3 d to 70 d and
preferably 5 d to 40 d where d is the diameter of at least the
smaller of the twisted strands. In another aspect, each mesh bar
comprises a strap of synthetic or natural fibers of either
rectangular, or quasi-rectangular cross section, preferably twisted
along its longitudinal axis of symmetry whereby in operation the
short sides form interchanging leading and trailing edges. In still
another aspect, the invention relates to cell construction
associated with tow, bridle and breast lines that attach to the
trawl and improved performance thereof. Result: rather deep grooves
are formed along the length of each cell bar that interact with
passing water during operations as explained below. Note in this
regard that the invention provides for a cell construction that can
be systemized. In the case of a trawl, the opposite mesh bars of
any rectangularly shaped mesh cell act as mini-hydrofoils or wings
in concert in operations. Such opposite bars (whether formed of a
series of twisted strands or of a single twisted strap), 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 remaining opposite
mesh bars of such mesh cell.
[0002] When incorporated in a trawl system, such cell construction
of the invention, provides for improved shaping and performance.
That is, the cells positioned at different geometrical locations
relative to and about the longitudinal central axis of the trawl,
can be controlled such that resulting trawl panels, wings, bridle
lines, towlines etc., act analogous to a series of mini-hydrofoils
capable of acting in concert in operation. Such concerted action
provides--when the trawl is in motion--outwardly directed force
vectors which increase--significantly--trawl system performance
characteristics including but not limited to overall trawl volume
while simultaneously--and surprisingly--decreasing drag and
background noise.
BACKGROUND OF THE INVENTION
[0003] It is well understood that the basic cell of a selected
portion of every trawl system net is the unit cell (called cell
hereinafter). The selected portions of the trawl system is then
built by repeating the basic shape.
[0004] It is axiomatic that the ability to predict the overall
shape and performance of the finished product depends entirely on
the shape and structural integrity of that single cell. Heretofore,
proper trawl making was a two-step process that involved initial
construction of undersized mesh cells, and setting the knots and
mesh sizes by the substeps of depth stretching and heat setting
involving turning the finished mesh in direction opposite to its
natural bent and applying pressure, and then applying heat to set
the knots.
[0005] Materials used in the mesh cell construction can be plastics
such nylon and polyethylene but other type of natural occurring
fibers also can be (and have been) used. Single, double (or more)
strands make up a thread or twine composed of, say, nylon,
polyethylene and/or cotton. Additionally, braided cords, of natural
and synthetic materials, as well as rope and cables, have been
used. However, the pitch of any braided or twisted thread, twine,
cord and/or rope (distance between corresponding points along one
of the strands constituting one turn thereof) which is analogous to
the pitch between corresponding screw threads), has been small.
Moreover, modern manufacturing processes use threads, twines,
cords, cables or ropes to form mesh cells, and have always produced
cells in which twist direction of the individual bars comprising
each cell, is always the same. None have proposed the use of
differently oriented twist of individual mesh bars of the mesh cell
in the manner provided by the instant invention.
[0006] Even though various Japanese Patent Applications
superficially deal with nets having differing twist directions,
(see for example, Jap. Pat. Apps. 57-13660, 60-39782 and 61-386),
these deal with a contrary goal than that of the instant invention,
viz., to a balancing of residual torque forces within the net
structure during construction thereof, not to the generation of
composite vector forces during actual field operations (via water
flow-net shape interaction) for enhancement of net performance. The
first-mention Application, for example, states that its purpose is
to provide "net legs with different twist directions according to a
fixed regular pattern so that torsion and torque of said net legs
are mutually canceled" and must generate substantially inconclusive
unbalanced forces during operations since the depicted net would
lead to a shrinkage in net volume, not increasing net volume as
provided by the instant invention.
SUMMARY OF THE INVENTION
[0007] The present invention is based on the discovery that
individual bars of a cell can be controlled to act as
mini-hydrofoils in operation. In one aspect, the invention controls
twist direction, either right-handed or left-handed in a receding
direction from a knot or equivalent coupler, in a fashion to
provide for an improved shaping and performance of resulting trawl
system.
[0008] In one aspect, the invention relates to mesh cell
construction for trawls that can be triangular, rectangular and/or
hexagonal in cross section (where such rectangular configurations
include square cells) and is associated with at least three and
preferably four cell (or more) bars in a common plane, with the
length of each bar being measured between a pair of normalized
transverse, quasi-transverse, longitudinal or quasi-longitudinal
spaced-apart knots or equivalent couplers. In accordance with the
invention, a pair of half mesh bars of each cell are constructed so
as to fan out from a common knot or coupler (of the four knots or
couplers associated with each quadratic mesh cell). Each mesh bar
of such pair is constructed to provide hydrofoil-like
characteristics in field operations. Each mesh bar comprises two
(or three or more) strands comprised of filamented synthetic
material such as plastic or naturally occurring substance, each
strand being the product of a conventional manufacturing process.
In accordance with the invention, such the strands are constructed
to be rather loosely twisted about a longitudinal axis of symmetry
in direction that is opposite (not the same) direction as its
mating mesh bar. In addition, the pitch of the twist is controlled
wherein each mesh bar defines a range of pitch values, say from 3 d
to 70 d with 5 d to 40 d being preferred where d is the diameter of
at least the smaller of the twisted strands. In addition, each mesh
bar can comprise a strap of synthetic or natural fibers of
rectangular, quasi-rectangular cross section, preferably twisted
along its longitudinal axis of symmetry whereby in operation the
short sides form interchanging leading and trailing edges. In still
another aspect, the invention relates to cell construction
associated with tow, bridle and breast lines that attach to the
trawl and improved performance thereof. Result: rather deep grooves
are formed along the length of each cell bar that interact with
passing water during operations as explained below. Note in this
regard that the invention provides for a cell construction that can
be systemized. In the case of a trawl the opposite mesh bars of any
rectangularly shaped mesh cell act as mini-hydrofoils or wings in
concert in operations. Such opposite bars (whether formed of a
series of twisted strands or of a single twisted strap), 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 remaining opposite
mesh bars of such mesh cell.
[0009] When incorporated in a trawl system, such cell construction
of the invention, provides for improved shaping and performance.
That is, the cells positioned at different geometrical locations
relative to and about the longitudinal central axis of the trawl,
can be controlled such that resulting trawl panels, wings, bridle
lines, towlines etc., act analogous to a series of mini-hydrofoils
capable of acting in concert in operation. Such concerted action
provides--when the trawl is in motion--outwardly directed force
vectors which increase--significantly--trawl system performance
characteristics including but not limited to overall trawl volume
while simultaneously--and surprisingly--decreasing drag and
background noise.
[0010] Definitions
[0011] MESH is one of the openings between threads, ropes or cords
of a net;
[0012] MESH CELL means the sides of a mesh and includes at least
three sides and associated knots or equivalent couplers oriented in
space. For a quadratic cell a longitudinal working plane bisects
the knots or couplers and sides and defines a rectangular
(including square) cross section with four sides and four knots or
couplers. For a triangular cell the longitudinal working plane
defines a triangular cross section with three sides and three knots
or couplers. For a hexagonal cell, the longitudinal working plane
defines a hexagonal cross section with six sides and six knots or
equivalent couplers;
[0013] MESH BARS means the sides of a mesh cell;
[0014] CELL means a construction unit of a trawl, net or the like
and includes both a mesh cell relating to enclosable sides of the
mesh of the trawl or net itself, as well as to bridle, breast and
tow lines used in transport of the trawl or net through a water
column to gather marine life.
[0015] CELL BAR means both the sides of a mesh cell and the
elements that make up the bridle, breast and tow lines.
[0016] RIGHT- AND/OR LEFT-HANDINESS IN A RECEDING DIRECTION along a
cell bar relates to the establishment of a central axis of the
trawl, net or the like for which the cell associated with the cell
bar relate, then with a normalized imaginary giant stick figure
positioned so that his feet intersect said central axis but
rotatable therewith and his back positioned to first intersect the
velocity vector of the moving trawl, net or the like associated
with cell, determining right- and/or left-handiness of the cell bar
using the location of either of right or his left arm of the such
giant stick figure irrespective of the fact that the cell bar
position relative to the central axis may be either above, below or
offset therefrom, wherein the giant figure always rotates about the
central axis and his arms penetrate through the cell bar.
[0017] HALF OF MESH CELL means one-half of the cell of the
invention is defined by a transverse working plane normal to the
longitudinal plane that passes through the centroid of each mesh
cell. For the quadratic cell, the transverse working plane passes
through two transverse knots or couplers and forms the base of the
half mesh cell and each half mesh cell includes a central knot or
coupler and two mesh bars consisting of two mesh bars. Each mesh
bar comprises a thread having hydrofoil characteristics in
operation.
[0018] THREAD or MESH BAR are equivalent mesh units and is composed
of, in accordance with the invention, of synthetic or natural
fibers having hydrofoil-like characteristics in field operation.
Firstly, a thread can comprise two strands twisted along the
longitudinal axis of symmetry in a loose fashion, say where the
pitch is in a range of 10 d-70 d where d is the diameter of the
larger of the strands or where d is their diameters if the same. Or
secondly, a thread can comprise a strap of solid geometric
configuration, say composed of fibers having hydrofoil-like
characteristics in operation.
[0019] STRAP is a flexible element of synthetic or natural fibers
that forms a mesh bar, the strap having a cross section that is
generally rectangular or can be quasi-rectangular with rounded
short sides and elongated long sides with or without camber. In
operation, the strap acts as a hydrofoil, preferably twisted along
its longitudinal axis wherein the short sides form interchanging
leading and trailing edges. Or where the strap is not twisted, the
long sides can be shaped relative to each to provide a pressure
differential therebetween resulting in hydrofoil-like effects.
[0020] PRODUCT STRAND includes the synthetic or natural fibers or
filaments used to form the construction unit of the invention which
is preferably but not necessarily the product of a conventional
manufacturing process, usually made of nylon, polyethylene, cotton
or the like twisted in common lay direction. Such strand can be
twisted, plaited, braided or laid parallel to form a sub-unit for
further twisting or other use within a mesh bar or a cell bar in
accordance with the invention.
[0021] NET is a meshed arrangement of threads that have been woven
or knotted or otherwise coupled together usually at regular
intervals or at intervals that vary usually uniformly along the
length of the trawl.
[0022] TRAWL is a large net generally in the shape of a truncated
cone including bridle fines and like means to keep its mouth open
and towlines to enable same to be trailed through a water column or
dragged along a sea bottom to gather marine life including
fish.
[0023] CODEND is a portion of a trawl positioned at the trailing
end thereof and comprises a closed sac-like terminus in which the
gathered marine life including fish are trapped.
[0024] FRAME is a portion of the larger sized meshes of a net or
trawl upon which is overlaid (and attached by a binding) a netting
of conventional twist.
[0025] PANEL is one of the sections of a trawl and is made to fit
generally within and about frames shaped by riblines offset from
the longitudinal axis of symmetry of the trawl.
[0026] PITCH is the amount of advance in one turn of one strand
twisted about another strand (or strands) when viewed axially. Or
common advance of the twist of the strap along its axis of
symmetry.
[0027] LAY is the direction in which the strands or the strap wind
when viewed axially and in a receding direction.
[0028] INTERNAL LAY OR TWIST is the direction of synthetic or
natural fibers comprising each product strand, is wound when viewed
axially and in a receding direction.
[0029] INTERNAL BRAID describes the method of formation of a
particular product strand.
[0030] TOW LINE comprises a cable, rope or the like that connects a
vessel at the surface of a body of water with the trawl, net or the
like. Such connection can bia via a trawl door and thence through a
bridle to the frontropes attached at the mouth of the trawl, net or
the like. In the absence of doors, the tow line can connect
directly to a bridle. A vessel or trawler usually employs two
towline, one positioned at the portside and one nearer the
starboard side.
[0031] FRONTROPE(S) is a term that includes all lines located at
perimeter edge of the mouth of the trawl, net or the like, such as
headrope, footrope ( or bottomrope) and breast lines. The
frontropes have a number of connections relative to each other and
to the bridle lines.
[0032] BRIDLES relates to lines that intersect the frontropes and
attach to the tow lines. For a particular port or starboard tow
line, a pair of bridles extend from a common connection point
therewith, back to the frontropes.
[0033] TRAWL SYSTEM is a term that includes the trawl, net or the
like in association with the tow lines therefor as well as the
frontropes and bridles lines.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a illustrative side view of a mid-water trawl
being towed by a vessel and indicates that the trawl system of the
invention can include the trawl, the tow lines, the bridles and the
frontropes;
[0035] FIG. 2 is another view of a trawl of FIG. 1 disconnected
from the towing apparatus and vessel;
[0036] FIG. 3 is a fragmentary enlargement of a mesh cell of the
trawl of FIG. 2;
[0037] FIGS. 4-7 are top views of a work station having a table,
reel, post and for producing a looped segment of the invention;
[0038] FIG. 8 is a top view of the segment of FIGS. 4-7 after a
counterclockwise twist has been applied;
[0039] FIG. 9 is a top view of another segment produced from FIGS.
4-7 after a clockwise twist has been applied;
[0040] FIG. 9a is top view of another work station for producing a
torque-free segment;
[0041] FIG. 9b is a top view of the segment of FIG. 9a after a
counterclockwise twist has been applied but before release from the
work station;
[0042] FIG. 9c is a top view of the segment of FIG. 9b after
release from the work station;
[0043] FIG. 9d is a top view of a mating segment after a clockwise
twist has been applied in the manner of the work station of FIG.
9a;
[0044] FIGS. 9e is a top view of first and second pairs of the
segments of FIGS. 9c and 9d produced by the method of FIG. 9a
placed in a X-pattern illustrating the formation of the mesh cell
of the invention;
[0045] FIG. 10 is a top view of sets of the segments of FIGS. 8 and
9 placed in an X-pattern illustrating the formation of the mesh
cell of the invention;
[0046] FIG. 11 is a force diagram of hydrodynamic forces acting on
the mesh cells of the invention in operation;
[0047] FIG. 12 is a section taken along line 12-12 of FIG. 2,
[0048] FIG. 13 is a section akin to that depicted in FIG. 12 in
which the bottom panel comprising the mesh cells of the invention
has been inverted so that its resultant hydrodynamically created
forces are directed inwardly toward the axis of symmetry of the
trawl;
[0049] FIG. 14 is also a section akin to that shown in FIG. 13 in
which bottom panel is composed of mesh cells constructed in
accordance with the prior art, i.e., the cells are formed of
threads of the same twist;
[0050] FIG. 15 is another top view of other sets of segments of
FIGS. 8 and 9 placed in an X-pattern illustrating an alternate
method of forming the mesh cell of the invention;
[0051] FIG. 15a is another top view of segments of FIG. 15 after a
central knot and twisting thereof has occurred;
[0052] FIG. 16 is yet another top view of yet other sets of the
segments of FIGS. 8 and 9 placed in an X-pattern illustrating yet
another alternate method of forming the mesh cell of the
invention;
[0053] FIG. 17 is still yet another top view of yet other sets of
segments of FIGS. 8 and 9 placed in an X-pattern illustrating yet
another alternate method of forming the mesh cell of the
invention;
[0054] FIG. 18 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention;
[0055] FIG. 19 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention;
[0056] FIG. 20 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention;
[0057] FIG. 21 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention;
[0058] FIG. 22 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention
[0059] FIG. 23 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention
[0060] FIG. 24 is a fragmentary perspective view of the sets of
segments of FIG. 23 further modified to provide an incremental
hydrodynamic force during operations;
[0061] FIG. 24a is a detailed akin to FIG. 24 showing an alternate
mesh bar construction using braided (not twisted) strands);
[0062] FIG. 24b is also a detailed akin to FIG. 24 showing a
combination of braided and twisted strands;
[0063] FIG. 24c is a detailed view of another mesh bar construction
using a combination of first and second pairs of twisted strands in
which each pair comprises first and second strands twisted each
other and in which the first pair is later twisted about the other
pair,
[0064] FIG. 25 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention;
[0065] FIG. 26 is yet still another top view of yet still other
sets of segments of FIGS. 8 and 9 placed in an X-pattern
illustrating yet still another alternate method of forming the mesh
cell of the invention;
[0066] FIG. 27 is a top view of a series of alternate mesh cells of
the invention in which each mesh cell is of a triangular cross
section in which the bases thereof are parallel to the axis of
symmetry of the group of alternate mesh cells and the apexes are
centered along the base of an adjoining cell;
[0067] FIG. 28 is another top view of another group of alternate
mesh cells of the invention in which each mesh cell is of a
triangular cross section in the bases thereof are parallel to the
axis of symmetry of the group and wherein the bases are formed of
larger diametered rope for better load carrying capability;
[0068] FIG. 29 is another top view of still another group of
alternate mesh cells of the invention in which each mesh cell is of
a triangular cross section but is formed of a single strap of
material of rectangular cross section in which the bases thereof
are substantially parallel to the axis of symmetry of the
group;
[0069] FIG. 30 is yet another top view of yet still another group
of alternate mesh cells of the invention in which each mesh cell is
of a hexagonal cross section in which the bases thereof are
substantially parallel to the axis of symmetry of the group;
[0070] FIG. 31 is a top view of the trawl of FIGS. 1 and 2 modified
to provide a netting of conventional design covering mesh cells
constructed in accordance with the invention;
[0071] FIG. 32 is a fragmentary perspective view of yet another
trawl system design of the invention including sub-headrope and
sub-footrope assemblies;
[0072] FIG. 32a is a fragmentary detail of another sub-headrope
assembly of the trawl system of FIG. 32 illustrating another cell
construction;
[0073] FIG. 32b is a fragmentary detail of another sub-footrope
assembly of the trawl system of FIG. 32 illustrating yet another
cell construction;
[0074] FIG. 33 is yet another top view of an alternative mesh cell
in which the mesh bars include a rectilinearly disposed cylindrical
first strand about which a second strand serpentines;
[0075] FIG. 34 is an enlarged detail taken along line 34-34 of FIG.
33;
[0076] FIG. 35 is a top view of another alternative mesh cell in
which the mesh bars include a rectilinearly disposed cylindrical
first strand about which a second strand serpentines;
[0077] FIG. 36 is an enlarged detail taken along line 36-36 of FIG.
35;
[0078] FIG. 37 is a top view of still anther alternative mesh cell
in which a rectilinearly disposed cylindrical first strand about
which a second strand (of reduced diameter) serpentines;
[0079] FIG. 38 is an enlarged detail taken along line 38-38 of FIG.
37;
[0080] FIG. 39 is an illustrative side view of trawl system in
accordance with the invention;
[0081] FIG. 40 is a top view of the trawl of the trawl system of
FIG. 39 disconnected from the towing vessel;
[0082] FIG. 41 is a fragmentary enlargement of a mesh cell of the
trawl of FIG. 40;
[0083] FIG. 42a is a section taken along line 42a-42a of FIG.
40;
[0084] FIG. 42b is a detail section akin to FIG. 42a showing an
alternative embodiment;
[0085] FIG. 42c is a detail section akin to FIG. 42a showing
another alternative embodiment;
[0086] FIG. 42d is a detail view-slightly enlarged-of alternate
connector for the mesh cell of FIG. 41;
[0087] FIG. 42e is a section taken along line 42e-42e of FIG.
42d;
[0088] FIG. 43 is a section taken along 43-43 of FIG. 40;
[0089] FIG. 44 is another fragmentary enlargement of an alternative
mesh cell of the invention;
[0090] FIG. 45 is a section taken along line 45-45 of FIG. 44;
[0091] FIG. 46 is yet another fragmentary enlargement of another
alternative mesh cell of the invention;
[0092] FIG. 47 is a section taken along line 47-47 of FIG. 46;
[0093] FIG. 48 is a section taken along line 48-48 of FIG. 46;
[0094] FIG. 49 is a section taken along line 49-49 of FIG. 46;
[0095] FIG. 50 is a graph of signal noise versus time of a twisted
stranded mesh cell based on experimental evidence as compared with
a conventional uni-twisted cell of the prior art;
[0096] FIG. 51 is a fragmentary enlargement of yet another
alternate mesh cell of the invention;
[0097] FIG. 52a is a detail view of an alternative connection for
the mesh cell of FIG. 51;
[0098] FIG. 52b is a section taken along line 52b-52b of FIG.
51a;
[0099] FIG. 53 is right side view of the trawl system of the
invention showing one embodiment of the starboard tow line of the
trawl system of the invention in towing contact with a starboard
frontropes of the trawl;
[0100] FIG. 54 is left side view of the trawl system of the
invention showing the embodiment of FIG. 53 in which the port tow
line of the trawl system of the invention in towing contact with
port frontropes of the trawl, is depicted;
[0101] FIG. 55 is a fragmentary side view of the embodiment of
FIGS. 53, 54;
[0102] FIG. 56 is a fragmentary top view of the embodiment of FIGS.
53, 54;
[0103] FIG. 57 is right side view of the trawl system of the
invention showing another embodiment of the starboard tow line of
the trawl system of the invention in towing contact with a
starboard frontropes of the trawl;
[0104] FIG. 58 is left side view of the trawl system of the
invention showing the embodiment of FIG. 57 in which the port tow
line of the trawl system of the invention in towing contact with
port frontropes of the trawl, is depicted;
[0105] FIG. 59 is a fragmentary side view of the embodiment of
FIGS. 57, 58; and
[0106] FIG. 60 is a fragmentary top view of the embodiment of FIGS.
57, 58.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0107] Referring to FIG. 1, there is shown a towing vessel 10 at
the surface 11 of the ocean 12 towing a mid-water trawl 13 of the
of the trawl system 9 of the invention. The trawl 13 is positioned
between the surface 11 and the ocean bottom 14. The trawl 13 can be
connected to the towing vessel 10 in many different configurations
and the one chosen includes a main towing line 18 connected through
door 19, towing bridles 20 and mini bridles 21, 22. A series of
weights 23 is attached to minibridle 22. Likewise, the shape and
pattern of the trawl 13 can vary as is well known in the art. As
shown, the trawl 13 shown includes wings 25 for better herding open
at mouth 26. The wings 25 are seen to define a mesh size that is
larger than that used to form mid-portion jacket 27, intermediate
portion jacket 28 or codend 29.
[0108] FIG. 2 illustrates the trawl 13 of FIG. 1 in more
detail.
[0109] As shown, the wing 25 includes a series of mesh cells 30 of
rectangular cross section that is part of a panel 31 offset from
axis of symmetry 32 of the trawl 13. The trawl 13 includes meshes
33 of a selected size determined by the length between adjacent
knots or equivalent couplers 34. The mesh cells 30 are of a general
rectangular cross section that is repeated through the longitudinal
and lateral scope of the trawl 13.
[0110] As shown in FIG. 3, the mesh cells 30 each have a
longitudinal axis of symmetry 30a parallel to the axis of symmetry
32 of the trawl 13 and are formed of a series of threads 35
comprising first and second product strands 36, 37. As explained in
more detail below, the product strands 36, 37 of each mesh cell 30
are twisted about a common axis of symmetry 38 either in one of two
lay directions: clockwise or counterclockwise as viewed axially
along longitudinal axis of symmetry 38 and in a receding direction
established at the mouth 26 of the trawl 13 (FIG. 1).
[0111] FIGS. 4, 5, 6 and 8 shows how a given segment of thread 35
is formed.
[0112] As show, a single strand 40 that is the product of a
conventional manufacturing process as well as has termini 41, is
formed in a loop 42 after which the termini 41 are permanently
attached together to form a spliced region 42a. Thereafter, ends 43
of the loop 42 are attached between a fixed post 45 and a reel 46
located on a table 44. The reel 46 has a handle 47 capable of
providing rotation to a spindle 48 attached to one end 43 of the
loop 42. Result: when the handle 47 is rotated in a
counterclockwise direction as indicated by arrow 49a, the loop 42
becomes twisted to form a counterclockwise lay segment 50 of thread
35, wherein segment 50 has a length L1 measured between the ends 43
and is composed of the first and second strands 36, 37 previously
mentioned wound in a counterclockwise lay direction (FIG. 8).
Thereafter, the method is repeated except that the handle 47 is
rotated in a clockwise direction (FIG. 7) wherein a new segment 51
(FIG. 9) is provided having a length L1 measured between ends 52,
53 and of course is composed of the strands 36', 37' twisted in a
clockwise direction, i.e. in a direction opposite to that of the
segment 50 composed of strands 36, 37. Note that the pitch Po of
the segments 50 and 51 are the same and is in a range of 3 d to 70
d where d is the diameter of the strands 36, 37, 36', 37'.
[0113] Note that the methods depicted in FIGS. 5-9 produces
segments 50, 51. Each segment 50 or 51, after twisting has
occurred, has turns which contain residual torque. Such torque can
be balanced by conventional thermal setting techniques,
however.
[0114] But a better method has been discovered in which the large
loops 42 (as depicted in FIG. 5-9) are eliminated prior to the
twisting process to permit the formation of torque-free
segments.
[0115] Such method is shown in FIG. 9a.
[0116] As shown in FIG. 9a, two (say first and second) strands 40'
are placed side-by-side of each other across a long table 44'. Each
of strands 40' have separate near and far termini 41' and 41". Each
near and far termini 41', 41" comprises first and second terminus
positioned side-by-side, i.e., so they are parallel to each other.
Then the parallel positioned near termini 41' at the near ends of
the first and the second strands 40' and 40" are formed into mini
loops 56. These mini loops 56 attach to the respective opposed
T-arms 48a of the spindle 48 as shown in FIG. 9b. The opposed
parallel far termini 41" of the same first and second strands 40'
and 40" are each then attached to a series of in-line conventional
barrel swivels 57a (such as used in removing torque in fishing
lines and purchasable at any sporting goods store) and thence
through a second residual strand 57b to a separate fixed post 45'
attached at the far end of the table 44'. Then with rotation of the
spindle 48 in a first direction, the first and second strands 40'
and 40" twisted together, while the residual strands 57b attached
thereto, are not so wound because of the action of the barrel
swivels 57a. After the mini loops 56 at the near termini 41' of the
first and second strands 40' and 40" (at the spindle 48) are
removed from contact with the T-arms 48a as are the far termini 41"
from the barrel swivels 57 followed by the formation of mini loops
similar in shape to the mini loops 56 for the near temini 41', the
result is segment 59a having a length L1 and a pitch Po in the
range precisely(?) set forth above, as shown in FIG. 9c. That is, a
segment 59a twisted in a left-handed or counterclockwise lay
direction is formed wherein the resulting turns have no or
substantially minimum residual torque. Hence thermal setting is
unneeded. Thereafter, the method is repeated but rotation of the
spindle 48 being in an opposite direction as shown, producing
segment 59b of FIG. 9d having a length Li and a pitch Po where Po
has a range of values as previously set forth. Further iteration of
the method produces further pairs of segments 59c and 59d which can
then be assembled together in a X-pattern as shown in FIG. 9e.
[0117] FIG. 9e shows a X-pattern layout of pairs of segments
59a-59d produced by the method of FIGS. 9a and 9b.
[0118] As shown, a pair of left-handed or counterclockwise segments
59a, 59c (each constructed as depicted in FIG. 9c and positioned
parallel to each other) is located in the aforementioned X-pattern
along with a pair of right-handed or clockwise segments 59b, 59d
(each constructed as depicted in FIG. 9d and positioned parallel to
each other). The segments 59a-59d are offset from a central axis
32' associated with the axis of symmetry of the trawl to be
manufactured and terminate in mini loops 56. The result is the
formation of a mesh cell 58 of a quadratic design in accordance
with the invention which consists of four mesh bars or sides
associated with sub-segments 59a', 59b', 59c' and 59d'. Note that
the two mesh bars or sides of the cell 58 associated with
sub-segments 59b', 59d' are of a right-handed or clockwise lay and
positioned parallel to each other while the two mesh bars or sides
of the cell 58 associated with sub-segments 59a' and 59c' are of a
left-handed or counterclockwise lay and are positioned parallel to
each other.
[0119] Assuring a normalizing receding direction in the manner of
arrow A', note that the sub-segments 59a' and 59b' diverge from a
common intersection point B' and leading and trailing edges are
established for each of the sub-segments 59a' and 59b' wherein the
leading edge for the sub-segment 59a' when normalized to the
receding direction arrow A' relative to the central axis 32',
reside at a right side of the sub-segment 59a' as viewed in the
receding direction arrow A' and wherein the leading edge of the
subsegment 59b' when normalized to the receding direction arrow A',
reside along a left side of the sub-segment 59b' as viewed in the
receding direction as indicated by arrow A'. Similarly, for the
sub-segments 59c' and 59d' converging toward common intersection
point B", leading and trailing edges are established for each of
the sub-segments 59c' and 59d' wherein the leading edge for the
sub-segment 59c' when normalized to the receding direction arrow A'
relative to the central axis 32', reside at a right side of the
sub-segment 59b' as viewed in the receding direction arrow A' and
wherein the leading edge of the subsegment 59d' when normalized to
the receding direction arrow A', reside along a left side of the
sub-segment 59d' as viewed in the receding direction as indicated
by arrow A'. Further characteristics of the mesh cell 58 is
discussed by inference in FIG. 10, below.
[0120] FIG. 10 shows the layout of a series of the segments 50, 51
to form the mesh cells 30 of the invention.
[0121] As shown, the clockwise lay directed segment 51 and
counterclockwise lay direction segment 50 are lain in a X-pattern
relative to each other when viewed in plan so that their mid-points
55 are coincident with and make intersection with each other and
with the axis of symmetry 30a of the cell 30 to be formed. That is,
the segment 50 is positioned such that its end 43a is offset a
distance D1 above the axis of symmetry 30a, while end 43b is offset
a distance D1 below the axis of symmetry 30a. And the segment 51 is
positioned such that its end 52 is offset a distance D1 below the
axis of symmetry 30a and its other end 53 is positioned above the
axis of symmetry 30a. Thereafter, a second pair of segments 50',
51' are likewise lain in X-pattern relative to each other wherein
their mid-points 55' are coincident with and make intersection with
each other and with the axis of symmetry 30a. That is, the end 53'
of clockwise twisted segment 51' overlays end 43a of
counterclockwise segment 50 and is thus, offset a distance D1 above
the axis of symmetry 30a. Similarly, end 52' of the segment 51' is
offset a distance D1 below the axis of symmetry 30a. In similar
fashion, end 43b' of counterclockwise twisted segment 50' overlays
end 52 of clockwise twisted segment 51, and thus, is offset a
distance D1 below the axis of symmetry 30a. Similarly, the end 43a'
of counterclockwise twisted segment 50' is positioned a distance D1
above the axis of symmetry 30a.
[0122] As a result, note that resulting mesh cell 30 is
rectangularly shaped and begins with a counterclockwise twisted
mesh bar 60 and clockwise twisted mesh bar 61 and ends with a
clockwise twisted mesh bar 62 and counterclockwise twisted mesh bar
63. Note that additional mesh cells can be formed at the exterior
of the mesh cell 30 in both longitudinal and transverse directions
relative to the axis of symmetry 30a by a continuation of the
method of the invention.
[0123] In more detail, counterclockwise mesh bar 60 starts at
intersection 55', diverges transversely outward relative to the
axis of symmetry 30a and terminates at the intersection of pair
ends 43b', 52, a distance D1 below the axis of symmetry 30a. While,
mating clockwise twisted mesh bar 61 starts at intersection 55',
diverges transversely outward relative to the axis of symmetry 30a
and terminates at the intersection of pair ends 43a, 53' a distance
D1 above the axis of symmetry 30a.
[0124] Clockwise mesh bar 62 starts at the intersection of pair
ends 43b', 52 a distance D1 below the axis of symmetry 30a,
diverges transversely inwardly relative to the axis of symmetry 30a
and terminates at the intersection 55. While, mating
counterclockwise twisted mesh bar 63 starts at the intersection of
ends 43a, 53', diverges transversely inward relative to the axis of
symmetry 30a and terminates at the intersection 55 coincident with
the axis of symmetry 30a.
[0125] Thereafter, the mesh bars 60, 61, 62, 63 can be permanently
attached together at intersections 55', 55 and at pair ends 43a,
53' and 43b', 52 via couplers not shown that are conventional in
the art, such as bindings, seams, braids, metallic bands or the
like, or the ends 43a, 53' and 43b', 52 may be joined to one
another.
[0126] Note that for the mesh cell 30, a longitudinal working plane
P1 is seen to bisect the mesh bars 60-63 and defines a rectangular
(including square) cross section.
[0127] Note that half of the mesh cell 30 means one-half of the
cell 30 as bisected by a transverse working plane P2 normal to the
longitudinal working plane P1, such working plane P2 passing
through centroid C, such centroid being positioned coincident with
the axis of symmetry 30a of the cell 30. For the quadratic mesh
cell 30, as shown, the transverse working plane P2 passes through
paired ends 43b', 52 and 53', 43a. Such working plane P2 forms the
base from which each half of the mesh cell 30 extends. Each of the
halves of the mesh cell 30 are positioned back-to-back normalized
to the transverse working plane P2. Note that in viewing half of
the mesh cell 30, one half faces forward toward the front of the
trawl 13 (FIG. 1) and such half includes the pair of mesh bars 60,
61 that have been twisted in opposite directions when viewed
axially and in a direction receding from intersection 55'. That is,
the mesh bar 60 begins at intersection 55' coincident with the axis
of symmetry 30a and is twisted in a counterclockwise direction; and
the mesh bar 61 also begins at intersection 55' and is twisted in a
clockwise direction. Similarly, the remaining half of mesh cell 30
faces backward toward the aft of the trawl 13 (FIG. 1) and includes
the pair of mesh bars 62, 63 that have been twisted in opposite
directions when viewed axially and in a direction receding from the
intersection of paired ends 43a, 53' and 43b', 52 and terminating
at intersection 55 coincident with the axis of symmetry 30a. That
is, the mesh bar 62 begins at the ends 43b', 52 coincident with the
transverse working plane P2 and is twisted in a clockwise
direction; and the mesh bar 63 begins at the ends 43a, 53' also
coincident with the transverse working plane P2 and is twisted in a
counterclockwise direction.
[0128] Operational Aspects
[0129] Now having described the method of forming the mesh cell 30
and the nature of the twist directions of the mesh bars 60-63, it
is now believed to be important to show how the twist directions
affect operations. In this regard, one-half mesh cell of the
invention as depicted in FIG. 10 has been tested in a flume tank by
locating the mesh bars 60, 61 between three posts positioned in
3-spot triangular orientation. That is, one post was located
slightly forward of the intersection 55' and two remaining posts
were positioned adjacent to the ends 53', 43a and 43b', 52. A
1-kilogram weight was positioned at the intersection 55' and its
normalized positioned noted. The half of mesh cell 30 was then
subjected to vertically distributed water flow at a velocity of 2
meters per second and pictures taken to show the change in position
of the weight. The results of the test are shown below.
[0130] Mesh bars 60, 61 Total length=1.4 meters
[0131] Pitch=35 d where d is 1 centimeter
[0132] Distance along transverse plane=1 meter
[0133] Lift distance of the 1-kilogram weight within a water
stream
[0134] of 2.0 meter per second=13.33 centimeters
[0135] FIG. 11 shows the engineering reasons for providing lift in
the operations of the mesh cell 30 of the invention.
[0136] As shown, the mesh 30 is seen to be bisected by longitudinal
working plane P1 previously mentioned wherein the plane P1 passes
through the common longitudinal axis of symmetry 30a of the mesh
bars 60, 61, 62 and 63. At the intersection of plane P1 with the
forward surface 69 of the mesh bar 60 note that water particles
that have a relative velocity vector V in the direction of water
flow arrow 71. Since the direction of twist of the mesh bar 60 is
counterclockwise, likewise the direction of grooves 70 of mesh bar
60 at the upper surface 72 is parallel of the larger of the
component of the relative velocity vector V. Similarly the
direction of twist of the grooves 73 of mesh bar 61 (being
clockwise) is also parallel of the larger of the component of the
relative velocity vector V as the grooves 73 initially make contact
with water flow arrow 71 at surface 74 of the mesh bar 61. Note in
this regard that angle alpha denotes angle of attack of the mesh
cell 30, i.e., the vertical angle between the direction of water
flow arrow 71 and the axis of symmetry 30a of the mesh cell 30, and
the angle alpha zero measures the transverse angle between the mesh
bar 60 and the direction of water flow arrow 71. When angle alpha
zero is between 10 to 70 degrees, the water particles splitting at
the intersection of plane P1 with the surfaces 69, 74 of the mesh
bars 60, 61 for flow about the mesh bars 60, 61, have large
components of force that maximize hydrodynamic forces acting normal
to the longitudinal working plane P1.
[0137] That is, due to position, orientation, and direction of
grooves 70, 73 relative to the direction of water flow force vector
V, the moving water passing over and under the mesh bars 60, 61
acquires both a forward and circular velocity wherein the direction
of the circular velocity is dependent upon lay direction of twist
of the mesh bars 60, 61 and angle alpha zero, the angle of attack
of the mesh bar 60. Moreover, with the twist lay direction of mesh
bars 60, 61 as shown, the magnitude of the circular velocity
component that passes over the upper surfaces of the mesh bars 60,
61 is larger than that which passes under the undersurfaces of such
mesh bars. The result is akin to the production of lift above the
wing of an airplane in which decreased pressure zones are provided
at the upper surfaces of the mesh bars 60, 61 resulting in creation
of lift force vector F having a upwardly directed direction that is
slightly angled inward toward the axis of symmetry 30a of the mesh
cell 30 due to the pressure differential at the adjacent surfaces
thereof. Resolution of the lift force F provides for a component Fn
normal to the longitudinal working plane P1 and tangential
component Ft and -Ft that are each inwardly directed towards the
axis of symmetry of the mesh cell 30. Note that the normal forces
Fn of the mesh bars 60, 61 are thus additive while the tangent
forces Ft and -Ft are equal and opposite. Result: if the mesh cell
30 is united with like cells to form a truncated conical trawl 13
as depicted in FIG. 12, such normal forces Fn are additive as a
function of radial angle T centered at axis symmetry 32 to
substantially increase the interior volume of the trawl 13 (see
FIG. 12) relative to longitudinal axis of symmetry 32. Likewise,
since there is cancellation of all tangential components (Ft, -Ft),
drag of the trawl 13 is also substantially reduced. Moreover, it is
also apparent that the direction of the resultant forces acting on
the trawl 13, say acting on bottom panel 77 of FIG. 13 during
operations, could be inverted from that depicted in FIG. 12 whereby
the normal forces Fny for the bottom panel 77 have a direction that
points inwardly of the trawl 13' toward the axis of symmetry 32'
causing outer surface 77a to become convexed relative to the axis
of symmetry 32'. Note that the shape of the bottom panel of the
trawl 13 could also be changed as depicted in FIG. 14 whereby outer
surface 77a' of the bottom panel 77' defines a longitudinal plane
P6 parallel to the axis of symmetry 32" of the trawl 13". Such a
construction occurs by forming the bottom panel 77' of mesh cells
constructed in accordance with the prior art, i.e., the cells are
formed of strands of the same twist.
[0138] Additional Method Aspects
[0139] FIG. 15 shows an additional method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a, 50b and 51a, 51b formed in a
X-pattern about a central point 80. Each subsegment is formed of a
two strands 81, 82 having loops 83 at exterior and interior end
segments 84, 85. The loops 83 having openings 86 large enough to
permit passage of selected subsegments through such openings 86 at
the intersection of the interior end segment 85 of the subsegments
to form handing knot 87, see FIG. 15a, at the central point 80.
Thereafter, the subsegments are twisted about central axes 88a, 88b
to provide the orientation depicted in FIG. 10. That is, the
subsegments 50a, 50b are twisted to form a counterclockwise lay
direction as viewed from exterior end segment 84a of subsegment
50a. Likewise, the subsegments 51a, 51b are twisted to form a
clockwise lay direction as viewed from exterior end segment 84b of
subsegment 51a.
[0140] FIG. 16 shows another method of formation of the segments
50, 51 of FIG. 10. As shown the segments 50, 51 are divided into
separate subsegments 50a', 50b' and 51a', 51b' formed in a
X-pattern about a central point 90. Each subsegment is formed of a
two strands 91, 92 having interior ends 93 that fit through radial
openings 94 in a collar 95. After attachment say via overhand knot
96, each subsegment is twisted as previously indicated above.
[0141] FIG. 17 shows yet another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a", 50b" and 51a", 51b" formed
in a X-pattern about a braided or woven intersection segment 97.
Each subsegment is formed of a two strands 98, 99 that attach
together via intersection segment 97. As shown, all strands 98, 99
are independent of each other. Thereafter, each subsegment is
twisted as previously indicated above.
[0142] FIG. 18 shows still another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a'", 50b'" and 51a'", 51b'"
wherein subsegment 50a'" is integrally united with subsegment 51a'"
and subsegment 50b'" is integrally united with subsegment 51b'" in
a X-pattern about separate braided or woven intersection segments
101. Each subsegment is formed of a two strands 102, 103 which are
twisted as previously indicated above.
[0143] FIG. 19 shows yet still another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a"", 50b"" and 51a"", 51b""
wherein subsegment 50a"" is integrally united with subsegment 51b""
and subsegment 50b"" is integrally united with subsegment 51a"" in
a X-pattern about separate braided or intersection segments 104.
Each subsegment is formed of two strands 105, 106 which are twisted
as previously indicated above.
[0144] FIG. 20 shows still yet another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a'"", 50b'"" and 51a'"", 51b'""
wherein subsegment 50a'"" is integrally united with subsegment
51a'"" and subsegment 50b'"" is integrally united with subsegment
51b'"" in a X-pattern about twine or metallic connector 107. Each
subsegment is formed of a two strands 108, 109 which are twisted as
previously indicated above.
[0145] FIG. 21 shows still yet another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a""", 50b""" and 51a""", 51b"""
wherein subsegment 50a""" is integrally united with subsegment
51a""" and subsegment 50b""" is integrally united with subsegment
51b""" in a X-pattern intertwined as shown to form knot 110. Each
subsegment is formed of two strands 111, 112 which are twisted as
previously indicated above.
[0146] FIG. 22 shows still yet another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 50, 51 are
divided into separate subsegments 50a'""", 50b'""" and 51a'""",
51b'""" formed in a X-pattern about braided or woven intersection
segments 113 formed by opening up strands 114, 115 of subsegments
50a'""", 50b'""" and passing subsegments 51a'""", 51b'"""
therethrough, then opening up strands 114, 115 of subsegments
51a'""", 51b'""" and passing subsegments 50a'""" and 50b'""",
therethrough. Thereafter, each subsegment is twisted as previously
indicated above. Note that the load bearing capability of
subsegments 51a'""" and 51b'""" are maximal.
[0147] FIG. 23 shows still yet another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 116, 117 are
integrally formed in a X-pattern about a seamed intersection
segment 118. The segments 116, 117 are each formed of separate
strands 119, 120. Thereafter the segments 116, 117 are twisted as
previously indicated above. Note in FIG. 24 that each strand 119,
120 can themselves be composed of substrands 119a, 119b, 119c and
120a, 120b, 120c. These sub-strands 119a-120c are provided a twist
direction that matches that of segment 116 or 117 into which the
former is incorporated. For example, since the segment 117 of FIG.
24 is provided with a clockwise direction. hence the sub-stands
119a-119c and sub-stands 120a-120c are also provided with a
clockwise direction. Result: there is an increase in the magnitude
of hydrodynamic forces generated in operations. That is, an
incremental circular vector V5 is created in addition to usual
vector force V6 created by water passage through grooves 121
between the sub-strands 119a-120c.
[0148] FIGS. 24a-24c illustrate variations in the construction of
the strands 119, 120 of segment 117 of FIG. 24. In FIG. 24a, the
strands 119', 120' are twisted in a right-handed or clockwise
direction about axis of symmetry 117a as previously mentioned, but
more particularly, each strand 119' or 120' is formed by a
conventional braided formation technique in which synthetic or
natural fibers or filaments are braided together about the axis of
symmetry 117a. In FIG. 24b, a combination of braided and
conventional twisted strands 119" and 120" is illustrated. That is,
note that strand 119" is of a conventional twisted line or rope
product formed of conventional synthetic or natural fibers or
filaments twisted about axis of symmetry 117b, as shown in FIG. 24.
While strand 120" is formed of a braided construction as
hereinbefore described with reference to FIG. 24a. In FIG. 24c, the
strands 119'" and 120'" (akin in twist direction to that of segment
116 of FIG. 23) have multiplied to form separate strand pairs 116',
116" nested together about axis of symmetry 117c in which the
dominated twist direction for all elements is counterclockwise or
left-handed. That is, note that segment 116' that comprises strands
119'" and 120"" twisted together in a left-handed direction, while
pair 116" that comprises strands 119"" and 120'" also twisted
together in a similar left-handed or counterclockwise direction.
Yet the pair segments 116', 116" also twist about each other in a
left-handed or counterclockwise direction relative to the axis of
symmetry 117c.
[0149] FIG. 25 shows still yet another method of formation of the
segments 50, 51 of FIG. 10. As shown the segments 122, 123 are
integrally formed in a X-pattern about a seamed intersection
segment 124. The segments 122, 123 are each formed of a single
strand 125 of material of rectangular cross section. Thereafter,
each subsegment is twisted as previously indicated above.
[0150] FIG. 26 shows yet another method of formation of the
segments 50, 51 of FIG. 10. As shown, the segments 126, 127 are
formed in X-pattern about a seamed region 128. The segments 126,
127 are each formed of three strands 129, 130, 131 twisted as
previously indicated.
[0151] Alternate Mesh Cell Designs
[0152] FIGS. 27-30 show alternate shapes for the mesh cell of the
invention.
[0153] As show in FIG. 27, a series of mesh cells 135 are depicted,
each of which being of a triangular cross section that includes
side mesh bars 136, 137 and base mesh bar 138. The side mesh bars
136, 137 meet each other at apex knot 139 and meet the base mesh
bar 138 at corner knots 140. The side mesh bars 136, 137 include
first and second strands 141, 142 which are twisted in opposite
directions, i.e., the strands 141, 142 which comprise mesh bar 136
are twisted in a clockwise direction while such strands which
comprise mesh bar 137 (when viewed from apex knot 139) are twisted
in a counterclockwise direction. And the base mesh bar 138 which
includes the strands 141, 142 twisted in a clockwise direction when
view axially from initiation of contact with the velocity vector V8
representing relative water flow during operations. Repeating the
shape of the series of mesh cells 135 places the apex knots 139 in
a common transverse plane P8. While the corner knots 140 are
longitudinally spaced a common longitudinal distance D4 that
repeats along the series of mesh cells 135. Note that the pitch Po
of the strands 141, 142 are common and are in a range of 10d to
70d. Result: hydrodynamic forces are created in which normalized
components of mesh bars 136, 137, 138 are additive in a direction
of arrow 143 out of the plane of FIG. 27 toward the viewer.
[0154] But in FIG. 28, the base mesh bar 138' is composed of a rope
of clockwise orientation of fibers in which the pitch P7 is less
than Po of the mesh bars 136', 137'. Results are identical but
since the longitudinal forces are born by the base mesh bars 138'
of greater load carry capability, the diameter of the mesh bars
136', 137' can be reduced with subsequent reduction in drag.
[0155] As shown in FIG. 29, the triangularly shaped mesh bars 143,
144 are composed of a single strand 146 of material of rectangular
cross section in which mesh bar 143 is twisted clockwise and mesh
bar 144 is twisted counterclockwise. Base mesh bar 145 is also
composed of a single strand 146 of material of rectangular cross
section is twisted in a clockwise direction as viewed from the
initialization of the mesh bars 143, 144, 145 with water flow
vector V9 in operations.
[0156] As shown in FIG. 30, a hexagonal mesh cell 150 is depicted,
and is composed mesh bars 151, 152, 153, 154, 155, and 156. The
mesh bars 151-156 are appropriately attached at braided
intersections 157a-157f. The mesh bar 151 includes first and second
strands 158, 159 which are twisted in a counterclockwise direction
when viewed from braided intersection 157a. The mesh bar 152 also
includes first and second strands 158, 159 which are twisted in a
clockwise direction when viewed from braided intersection 157a.
Mesh bars 153, 154 also includes first and second strands 158, 159
which are twisted in a clockwise direction when viewed braided
intersection 157b or 157c. Mesh bar 155 also includes first and
second strands 158, 159 which are twisted in a counterclockwise
direction when viewed from braided intersection 157d. And mesh bar
156 also includes first and second strands 158, 159 which are
twisted in a clockwise direction when viewed from braided
intersection 157e. Note that the pitch Po of the strands 158, 159
are common and are in a range of 10d to 70d. Result: hydrodynamic
forces are created in which normalized components of mesh bars
151-156 are additive in a direction of arrow 160 out of the plane
of FIG. 30 toward the viewer.
[0157] Alternate Trawl Designs
[0158] FIGS. 31 and 32 show variations in trawl designs using the
mesh cell of the invention.
[0159] As shown in FIG. 31, a modified trawl 161 is depicted in
accordance with the invention. In this aspect the mesh cells 162 of
the invention are created in the fashion previously described so
that subsequent operations generates increased volume of the trawl
161. However, such operations are unaffected by the fact that the
trawl 161 is overlaid with netting 163 of a conventional twist,
i.e., of a common direction. In this embodiment, the trawl 162 acts
as frame to accommodate the netting 163 while the mesh cells 162
provide for increased volumetric performance as previously
mentioned.
[0160] As shown in FIG. 32, a further modified trawl 165 is
illustrated in accordance with the invention. Trawl 165 comprises
the following: (i) mesh cells 166 formed in accordance with
invention, (ii) headrope 167 bisected at midpoint 168 to define a
left-hand lay sub-headrope 167a and a right-hand lay sub-headrope
167b, and (iii) footrope 169 comprising right hand lay sub-footrope
169a and left-hand lay sub-footrope 169b extending from bottom
segments 170. In subsequent operations, as previously discussed,
the twist directions of the headrope 167 provides for generation of
upwardly, vertical force vectors 171. During similar operating
conditions, the footrope 169 provides for generation of downwardly,
vertical directed force vectors 172. Result: a substantial increase
in the size of opening 173 measured between the headrope 167 and
the footrope 169.
[0161] FIGS. 32a and 32b show variations in the headrope 167 or
footrope 169 in which the cell construction depicted in FIGS. 32 is
changed. In more specific reference to FIG. 32a, a detail of
sub-headrope 167a' comprises an axis of symmetry 175, a first
cylindrical strand 176 having internal axis of symmetry coincident
with the axis of symmetry 175 and a second strand 178. The first
strand 176 is hence in an unwound state while the second strand 178
is seen to wind about the first strand 176 to define a series of
turns 180 in tangential contact with outer surface 181 thereof.
Ratio of the diameters of the strands 176, 178: preferably 1:1 but
can be larger say 2:1 to about 4:1. Direction of twist of second
strand 178: the same as before, i.e., in a left-handed or
counterclockwise lay. Note that any transverse cross section of the
first strand 176 is circular and the outer surface 181 thereof is
equi-spaced from both the internal axis thereof and the axis of
symmetry 175 of the sub-headrope 167a'. Note that the mate of the
sub-headrope 167a' would have a similar construction as the latter
but with opposite winding as that shown.
[0162] In FIG. 32b, a detail of sub-footrope 169a" comprises an
axis of symmetry 183, a first cylindrical strand 184 having
internal axis of symmetry coincident with the axis of symmetry 183
and a second strand 186. The first strand 184 is hence in an
unwound state while the second strand 186 is seen to wind about the
first strand 184 to define a series of turns 187 in tangential
contact with outer surface 188 thereof. Ratio range of the
diameters of the strands 184, 186: preferably about 1:1 but can be
larger say from 2:1 to 4:1. Direction of twist: the same as before,
i.e., in a right-handed or clockwise lay. Note that any transverse
cross section of the first strand 184 is circular and the outer
surface 188 thereof is equi-spaced from both the internal axis 185
thereof and the axis of symmetry 183 of the sub-footrope 169a'.
Note that the mate of the sub-footrope 169a' would have a similar
construction to the latter but with opposite winding as that
shown.
[0163] Still Further Aspects
[0164] FIG. 33 shows an alternative mesh cell 200. The mesh cell
200 comprises four mesh bars--viz., mesh bars 201, 202, 203 and
204. Each mesh bar 201-204 has an angulated axis of symmetry 205
and includes a first strand 210 and a second strand 211. As
explained in more detail below, the first strand 210 can be created
using a conventional manufacturing process (or otherwise as
previously explained) and includes an outer surface 212. Such outer
surface 212 defines a common diameter D. The outer surface 212 is
seen not to undulate relative to the axis of symmetry 205 of each
mesh bar 201-204 but instead remain parallel thereto throughout the
length of the latter, beginning from upstream point 206. That is,
the axis of symmetry 209 of the first strand 210 remains coincident
with the axis of symmetry 205 over the entire length of each mesh
bar 201-204 and is not twisted about such axis of symmetry 205.
[0165] However, this is not the case with regard to the second
strand 211. It is seen to be twisted about such axis of symmetry
205 of each mesh bar 201-204 in helical fashion and to form a
series of turns 195 in contact with the outer surface 212 of the
first strand 210. The direction of the turns 195 in contact with
the outer surface 212 of the first strand 210 is in either one of
two directions thereabout--clockwise or counterclockwise as viewed
along the axis of symmetry 205 in a receding direction established
at the upstream end 206 of each mesh bar 201-204.
[0166] In more detail with regard to mesh bar 201, the second
strand 211 is constructed to define a clockwise lay direction. As
to mesh bar 202, the second strand 211 defines a counterclockwise
lay direction. With respect to mesh bar 203 (opposite to mesh bar
201), the second strand 211 is created to provide a clockwise lay
direction. Finally, with regard to mesh bar 204 (opposite to mesh
bar 202), the second strand 211 defines a counterclockwise
direction.
[0167] FIG. 34 shows an enlarged view of the outer surface 212 of
the first strand 210 of the mesh bar 201 in contact with turns 195
of the second strand 211. Note that the first strand 210 may be
constructed of one (or more) twisted thread or threads 215 defining
a lay direction (normalized relative to the upstream end 206), that
is opposite to the lay serpentining direction of the second strand
210 about the first strand 210. In that way, a series of openings
196 are provided adjacent to intersections 197 between the turns
195 and the outer surface 212 of the first strand 210 that aid in
creating macro-lift vectors during operations apart from the lift
mechanism(s) previously described.
[0168] Since the direction of twist of the threads 215 making up
the first strand 210 is based upon the lay serpentining direction
of second strand 211 about such first strand 210 as each mesh bar
201-204 is constructed, note in FIG. 33 that the lay direction of
second strand 211 associated with the mesh bar 201 is clockwise.
Hence, the twist direction of threads 215 comprising the first
strand 210 for such mesh bar 201 is counterclockwise. A similar
construction scheme is used for the remaining mesh bars 202-204
wherein the lay direction of the threads 215 associated with the
first product strand 210 is clockwise, counterclockwise, and
clockwise, respectively, for the mesh bars 202, 203 and 204.
[0169] FIG. 35 shows yet another alternative mesh cell 220
comprising four mesh bars--viz., mesh bars 221, 222, 223 and 224.
Each mesh bar 221-224 has an angulated axis of symmetry 225 and is
composed a first strand 230 as hereinbefore described. However,
instead of a single strand, note that the invention embodied within
the mesh cell 220 includes a like oriented pair of second and third
strands 231, 232 that serpentine about the first strand 230. As
previously explained, the first strand 230 has an outer surface 226
defining a common diameter Do, such outer surface 226 remaining
parallel to the axis of symmetry 225 beginning at upstream point
227. That is to say, note that the internal axis of symmetry 229 of
the first strand 230 remains coincident with the axis of symmetry
225 of mesh bar 221-224 over the entire length of the latter and is
not twisted about such axis of symmetry 225. However, the pair of
second and third product strands 231, 232 is twisted about such
axis of symmetry 225 of each mesh bar 221-224 in uniform fashion to
form turns 219 in contact with the outer surface 226 of the first
strand 230 in either one of two directions--clockwise or
counterclockwise as viewed along the axis of symmetry 225 in a
receding direction established at the upstream end 227 of each mesh
bar 221-224.
[0170] In more detail with regard to mesh bar 221, the pair of
second and third strands 231, 232 is constructed to each provide a
clockwise lay direction. As to mesh bar 222, the pair of second and
third strands 231, 232 defines a counterclockwise lay direction.
With respect to mesh bar 223 (opposite to mesh bar 221), the pair
of second and third strands 231, 232 is created a clockwise lay
direction. Finally, with regard to mesh bar 224 (opposite to mesh
bar 222), the pair of second and third strands 231, 232 defines a
counterclockwise direction.
[0171] FIG. 36 shows an enlarged view of the outer surface 226 of
the first strand 230 of the mesh bar 223. Note that the first
strand 230 is similar in construction to that previously described
and includes one or more twisted threads 235 defining a lay
direction that is opposite to the direction of the pair of second
and third strands 231, 232. That is, since the lay direction of the
pair of second and third strands 231, 232 of the mesh bar 223 is
clockwise, the twist direction of threads 235 comprising the first
strand 230 is counterclockwise. A similar construction scheme is
used for the remaining mesh bars 221, 222 and 224 wherein the lay
direction of the threads 235 associated with the mesh bars 221,
222, and 224, is counterclockwise, clockwise, and clockwise,
respectively.
[0172] FIG. 37 shows still yet another alternative mesh cell 240
comprising four mesh bars--viz., mesh bars 241, 242, 243 and 244.
Each mesh bar 241-244 has an angulated axis of symmetry 245 and is
composed of a first strand 250 of diameter D1 and a second strand
251 of diameter D2 where D2=1/2 D1. As previously explained, the
first strand 250 has an outer surface 252 defining the
aforementioned diameter D1, such outer surface 252 remaining
parallel to the axis of symmetry 245 beginning from upstream point
246. That is, the axis of symmetry 249 of the first strand 250
remains coincident with the axis of symmetry 245 over the entire
length of mesh bar 241-244 and is not twisted about such axis of
symmetry 245. However, the second strand 251 is twisted about such
axis of symmetry 245 of each mesh bar 241-244 in contact with the
outer surface 252 of the first strand 250 in either one of two
directions--clockwise or counterclockwise as viewed along the axis
of symmetry 245 in a receding direction established at the upstream
end 246 of each mesh bar 241-244.
[0173] In more detail with regard to mesh bar 241, the second
strand 251 is constructed in a clockwise lay direction. As to mesh
bar 242, the second strand 251 defines a counterclockwise lay
direction. With respect to mesh bar 243 (opposite to mesh bar 241),
the second strand 251 is created a clockwise lay direction.
Finally, with regard to mesh bar 244 (opposite to mesh bar 242),
the second strand 251 defines a counterclockwise direction.
[0174] FIG. 38 shows an enlarged view of the outer surface 252 of
the first strand 250 of the mesh bar 243 in contact with the second
strand 251. Note that the first strand 250 is constructed of
braided construction while the second strand 251 is constructed of
one (or more) twisted thread or threads 255 defining a lay
direction that can be the same as or can be opposite to its lay
serpentining direction about the first strand 250. In either
circumstance, a series of openings 256 are provided adjacent to
intersections 257 and the outer surface 252 of the first strand 250
that aid in creating macro-lift vectors during operations as
previously mentioned, such vectors being separate and apart from
the main lift mechanism(s) previously described.
[0175] Aspects Associated with the Trawl System of the
Invention
[0176] FIG. 39 shows another embodiment of the invention. A towing
vessel 260 is shown the surface 261 of a body of water 262 towing a
mid-water trawl 263 of the trawl system 264 positioned between
surface 161 and the bottom 265. The trawl system 264 includes the
trawl 263 connected to the vessel 260 via main tow lines 268, doors
269, towing bridles 270, mini bridles 270a, and frontropes 271 that
include breastlines 271a, headropes 271b (see FIG. 40),
minibridles, etc. A series of weights 272 attach to the bridles
270. The trawl 263 is made up four panels (tow side panels, a top
panel and a bottom panel), and includes wings 274 for a better
herding at open mouth 275. The wings 274 are seen to define a mesh
size that is larger than that used to form mid-portion jacket 276,
intermediate jacket 277 or codend 278. As shown in FIG. 40, the
wing 274a includes a series of mesh cells 280 of rectangular cross
section that are offset from the central axis of symmetry 281 of
the trawl 263.
[0177] FIGS. 40 and 41 show the mesh cells 280 in more detail.
[0178] As shown in FIG. 40, the mesh cells 280 each have a
longitudinal axis of symmetry 282 that is offset from the central
axis of symmetry 281 of the trawl 263. Since the shape of the trawl
263 varies along the axis of symmetry 281 from almost cylindrically
shaped at the wing 274a to a more frustoconical shape over the
remainder, the position of the axes of symmetry 282 of individual
cells 280 vary with respect to the axis of symmetry 281, from
parallel and coextensive, non-parallel and non-intersecting and/or
to non-parallel and intersecting. But note that axes of symmetry
282 of the cells 280 are always offset therefrom.
[0179] In FIG. 41, each cell 280 is formed of a plurality of straps
284 formed into a X-pattern using a series of connections 285 to
maintain such orientation. Each strap 284 is twisted, such
direction being normalized to the receding direction of use, as
indicated by arrow 286, such twisting occurring about its own axis
of symmetry 286 in either one of two lay directions: left-handed or
clockwise or right-handed or counterclockwise as viewed relative to
the central axis 281 of the trawl 263 (see FIG. 40). As a result,
leading and trailing edges 287 are formed.
[0180] As shown in FIGS. 42a, 42b and 42c, the cross section of
each strap 284 is seen to be basically rectangular. In FIG. 42a,
the twisted strap 284 includes rounded short sides 284a and
parallel long sides 284b with the leading and trailing edges
occurring at the short sides 284b alternating between the former
and the latter based on the pitch, as explained below. In FIG. 42b,
instead of the cross section being of a solid geometrical
rectangle, strap 284' includes a side wall 290 defining a cavity
291 into which three strands 292 reside--in side-by side fashion.
That is, outer surfaces 293 of the three strands 292 have
tangential contact with each other as well as inner surface 290a of
the oval side wall 290. In FIG. 42c, strap 284" includes side wall
295 defining a cavity 296 into which two strands 297 reside--in
side-by side fashion. That is, outer surfaces 297a of the two
strands 297 have tangential contact with each other as well as
inner surface 295a of the oval side wall 295.
[0181] FIG. 42d shows an alternate connection 285' in which the
long sides 284b' of adjacent X-ed straps 284 are attached together
in a butting relationship. A series of seams 298 provide for such
attachment as shown in FIG. 42e. The seams 298 are parallel to
short sides 284a'.
[0182] Note that the right-handiness or left-handiness twist of the
straps 284 of FIG. 41 is determined using the concept of a figure
of man 298 as shown in FIG. 43 as a normalizing icon positioned as
described below. Note that the figure 298 has feet 299 rotatable
affixed to the central axis 281 of the trawl 263. As the trawl 263
and figure 298 are moved through the water, the figure 298 faces
downstream so that his back first encounters the resistance
provided by the water to the moving trawl 263. Hence, the figure
298 always looks in the direction of the arrow 286 with reference
to the cell 280 of FIG. 41, in a receding direction relative to
such movement. The right-handed (clockwise) or left-handed
(counterclockwise) twist of the straps 284 is hence based of the
particular position of the right arm 300 versus left arm 301 as so
positioned. Since the figure 298 can rotate relative to the central
axis 281, the twist direction of each strap 284 can be easily
determined irrespective of the fact that the particular strap 284
is positioned above, below or offset to the side from the central
axis 281.
[0183] FIG. 44 shows another mesh cell embodiment.
[0184] As shown, the mesh cell 280' is formed of a plurality of
straps 303 formed into a X-pattern using a series of connections
299 to effect such orientation. Each strap 303 is untwisted and can
be of a quasi-rectangular in cross section as shown in FIG. 45.
Note that each such strap 303 in cross section includes long sides
304 and short sides 305. The short sides 305 form either the
leading or trailing edges of the straps 303. In order have the
capability of a hydrofoil, the exterior far long side 304a
(exterior relative to the central axis 281 of the trawl) is
preferably cambered relatively more than the near long side 304b.
As a result, lift vector 307 is provided. In addition, the short
sides 305 can be rounded at corners 305a. The ratio of width W to
thickness T of the strap 303 is as set forth supra.
[0185] FIG. 46 shows an alternate strap design. As shown, the
straps 303' are untwisted and have a X-pattern layout as previously
described wherein the particularly straps 303' form the four mesh
sides and use a series of connections 306 to maintain such
orientation. Each strap 303' is of a quasi-rectangular in cross
section as shown in FIG. 47. Note that each such strap 303'
includes long sides 308 and short sides 309. The short sides 309
form either the leading or trailing edges of the straps 303'. In
order have the capability of a hydrofoil, the exterior far long
side 308a (exterior relative to the central axis 281 of the trawl)
is preferably cambered relative to uncambered near long side 308b,
via placement of a series of shape-altering support sleeves 310
therealong, see FIG. 46. As a result, lift vector 311 of FIG. 47 is
provided. In addition, the short sides 309 can be rounded at
corners 309a. The ratio of width W to thickness T of the strap 293'
is preferably as previously stated, greater that 1.1.1 and
preferably in a range of 2:1 to 10:1 but can be as large as 1.1:1
to 50:1.
[0186] FIG. 48 shows the support sleeve 310 in more detail.
[0187] Each sleeve 310 is preferably of plastic (but metals can be
substituted) and includes a cavity 312 having common cambered long
side surfaces 312a and short side surfaces 312b built to accept
each strap 303' even though the latter is of a rectangular cross
section, and reform the cross section of the latter to match the
cross sectional shape of the cavity 312. As a result, the lift
vector 311 is provided in a direction away from the central axis of
the trawl. Leading and trailing edges 313 thereof are as
depicted.
[0188] FIG. 49 shows one of the connections 306 in more detail.
[0189] As shown, the connection 306 has its long sides 308 of
adjacent X-ed straps 303' are attached together after each of the
long sides 308a', 308b' have been folded into two plies. A series
of seams 315 provide for such attachment. The seams 315 are
parallel to short sides 309a', 309b'.
[0190] Attributes are provided by the quasi-rectangular cross
sectional straps 303, 303' that, in operations, relate primarily to
reducing the noise and drag of the trawl system 264 of FIG. 39
whether such straps 303, 303' are used in FIG. 39 in the
construction of the trawl 263, main tow lines 268, towing bridles
270 and/or frontropes 271 that include breastlines, footropes,
headropes, minibridles, etc., as explained below. Suffice it to
say, experiments have shown a rather large reduction in noise using
the cell design of the present invention when compared to
conventional cell designs.
[0191] With reference to FIG. 50, graph 320 shows the relationship
between generated noise in dB versus time for two separate,
independent cell bar designs--curve 321 for a conventional
uni-twisted cell bars presently used in construction of the trawls
and the like, and curve 322 associated with bi-directional twisted
strands construction in accordance with the teachings of the
invention. Note over the time interval 6-10, there is a 20 dB
improvement in the cell construction in accordance with the
invention.
[0192] FIG. 51 shows an alternate layout for the straps.
[0193] As shown, the straps 330 include clock-wise lay segments 331
and counterclockwise segments 332 lain in an x-pattern so that
midpoints 333 are coincident with and make intersection with each
other at connections 334. Each segment 331 is positioned so that
its end 331a (that aids in defining the resulting cell 334) is
offset a distance D1 above axis of symmetry 335 while end 331b is
offset a distance D1 below the axis of symmetry 335. The segments
332 are positioned (relative to the cell 334) so that an end 332a
is offset a distance D1 below axis of symmetry 335 while end 332b
is offset a distance D1 above the axis of symmetry 335. Thereafter
additional pairs of segments (akin to the segments 331, 332) are
similar constructed and positioned along the lines previously
described, supra.
[0194] FIG. 52a and 52b show alternate details of a connection 334'
in which the long sides 338a of adjacent X-ed straps 330 are
attached together. A series of seams 339 provide for such
attachment. The seams 339 are parallel to short sides 338b.
[0195] FIGS. 53, 54, 55 and 56 show the cell design of the
invention used in the construction a tow line assembly 348. In
detail, the FIG. 53 shows starboard tow line 349 and FIG. 54 shows
a port tow line 350. Both are offset from central axis 351, see
FIGS. 55 and 56 midway between them. In FIG. 53, note that the
starboard tow line 349 comprises first and second product strands
352, 353 and is twisted about axis of symmetry 354 in a right-hand
or clockwise direction normalized to vessel 355. In
[0196] FIG. 54 the port tow line 350 is shown to included first and
second product strands 357, 358 twisted about its axis of symmetry
359 in a left-hand or counterclockwise direction normalized to
vessel 355.
[0197] Result of the action of FIGS. 53-56: force vectors are
generated which spread the towlines 349, 350 relative to the
central axis 351 midway between them and increase the volume of the
trawl 360.
[0198] FIGS. 57, 58, 59 and 60 are similar depictions in regard to
tow line assembly 348' to those shown in FIGS. 53-56 except for the
most part, twisted straps 365, 366 are substituted for the strand
pairs 352, 353, and 357, 358, respectively used in the tow line
assembly 348. In detail, the FIG. 57 shows starboard strap tow line
349' and FIG. 58 shows a port tow line 350'. Both are offset from
an central axis 351' midway between them. Twist directions are also
similar. In more detail, the starboard strap 365 related to the
starboard tow line 349', is twisted in a right-handed or clockwise
direction normalized to the vessel 355' and wherein strap 366
associated with the port tow line 350', is twisted in a left-handed
or counterclockwise direction, as viewed.
[0199] Results of FIGS. 57-60: force vectors are generated which
spread the towlines 349', 350' relative to the central axis 351'
and increase the volume of the trawl 360'.
[0200] Still further, FIGS. 53-56 also illustrate the cell design
of the invention, say when used in the constructing and using
bridle assemblies generally indicated at 370, 370' offset from the
central axis 351 of the trawl 360 which causes spreading of the
trawl and an increase in volume.
[0201] FIG. 53 shows the starboard bridle assembly at 370. It
includes a lower starboard bridle 372 composed of a pair of strands
373, 374 twisted about axis of symmetry 375 in a right-handed or
clockwise direction offset from central axis 351. Connection with
the starboard tow line 349 is at connector 376. A weight 371 along
the bridle 372 positions the same correctly. On the other hand,
upper starboard bridle 377 comprises a pair of strands 378, 379,
twisted about axis of symmetry 380 in a left-handed or
counterclockwise direction and also connects to the starboard tow
line 349 at the connector 376.
[0202] In FIG. 54 showing the port bridle assembly 370', note that
the same includes lower port bridle 381 composed of a pair of
strands 383, 384 twisted about axis of symmetry 385 in a
left-handed or counterclockwise direction. Connection with the port
tow line 350 is at connector 386. A weight 371' along the bridle
381 correctly positions the same. On the other hand, upper port
bridle 388 comprising a pair of strands 389, 390, is twisted about
its axis of symmetry 391 in a right-handed or clockwise direction.
It also connects to the port tow line 350 via the connector 386.
Result: force vectors are generated at mouth 393 of the trawl 360
resulting in an increase in its volume relative of central axis
351.
[0203] With further regard to bridle construction, note that FIGS.
57 and 58 are similar depictions to those shown in FIGS. 53 and 54
except that pairs of starboard and port straps, viz., starboard
strap pair 395, 396 and port strap pair 397, 398, respectively are
substituted for the stranded pairs of starboard and port bridles
viz., for starboard strand pairs 373, 374 and 378, 379, and for
port strand pairs 383, 384 and 389 and 390 also respectively. Twist
directions remain the same. In more detail, the lower starboard
strap 395 associated with the starboard towline 349' via connector
400, is twisted in a right-handed or clockwise direction normalized
to the vessel 355' and wherein upper starboard strap 396 associated
with the starboard tow line 349', is twisted in a left-handed or
counterclockwise direction, as viewed. And in FIG. 58, the lower
port strap 397 associated with the port tow line 350' via connector
401, is twisted in a left-handed or counterclockwise direction
normalized to the vessel 355' and wherein upper port strap 398 also
associated with the port tow line 350', is twisted in a
right-handed or clockwise direction, as viewed.
[0204] Results of FIGS. 57 and 58 with regard to bridle
construction: force vectors are generated which spread the trawl
360' and increase its volume relative to its central axis of
symmetry 351' (FIGS. 59 and 60).
[0205] Still further, FIGS. 53, 54 and FIGS. 57, 58 also illustrate
the cell design of the invention, say when used in the constructing
and using a frontrope assembly such as breast line assemblies
generally indicated at 405, 405' offset from the central axis 351,
351' of the trawl 360, 360', respectively (FIGS. 55, 56, 59, 60)
which result in spreading of the trawl and an increase in
volume.
[0206] FIGS. 53 and 57 show the starboard breast line assembly 405.
It includes a lower starboard breast line 406 (FIGS. 53 and 57)
composed of a pair of strands 407, 408 and twisted about axis of
symmetry 409 in a left-handed or counterclockwise direction offset
from the central axis 351, 351'. Connection with the lower
starboard stranded bridle 372 (FIG. 53) or with the lower starboard
strapped bridle 395 (FIG. 57) is at connection 410. On the other
hand, upper starboard breast line 411 (FIGS. 53 and 57) comprises a
pair of strands 412, 413, twisted about axis of symmetry 414 in a
right-handed or clockwise direction and also connects to the upper
stranded starboard bridle 377 (FIG. 53) or with the upper strapped
starboard bridle 396 (FIG. 57) at the connection 415.
[0207] In FIGS. 54 and 58 show the port breast line assembly 405'
which has a similar construction as starboard breast line assembly
405, such port breast line assembly 405' being best shown in FIG.
58 and including a lower port breast line 415 composed of a pair of
strands 416, 417 and twisted about axis of symmetry 418 in a
right-handed or clockwise direction offset from the central axis
369, 351, 351'. Connection with lower strapped port bridle 397
(FIG. 58) is at connection 419 or with the lower stranded port
bridle 381 (FIG. 54) at a similar connection 419. On the other
hand, upper port breast line 420 comprises a pair of strands 421,
422, twisted about axis of symmetry 423 in a left-handed or
counterclockwise direction and also connects to the upper strapped
port bridle 398 (FIG. 58) at the connector 425 or with the upper
stranded port bridle 388 (FIG. 54) at a similar positioned
connection 425.
[0208] Results of FIGS. 53, 54 and FIGS. 57, 58 with regard to
breast line construction: force vectors are generated which spread
the trawl 360, 360' and increase its volume relative to its central
axis of symmetry 351, 351'.
[0209] Still further, FIGS. 55 and 59 also illustrate the cell
design of the invention in another aspect, say when used in the
constructing and using a frontrope assembly such as a headrope
assemblies generally indicated at 430, 430' offset from the central
axis 351, 351' which result in spreading of the trawl and an
increase in volume.
[0210] FIG. 55 shows headrope assembly 430 in more detail. It
includes a starboard headrope subassembly 431 and a port headrope
subassembly 432 each composed of a pair of strands: subassembly 431
including strands 433, 434 and subassembly 432 comprising strands
435, 436. The subassemblies 431, 432 meet at connection 437 in a
vertical plane through the central axis 351. In detail, the strands
433, 434 are twisted about axis of symmetry 438 in a left-handed or
counterclockwise direction. On the other hand, the strands 435, 436
are twisted about axis of symmetry 439 in a right-handed or
clockwise direction. Connection of the subassemblies 431, 432 with
the upper starboard bridle 377 and upper port bridle 388 is at
connector 440 or equivalent.
[0211] FIG. 59 shows headrope assembly 430' which includes a
starboard subassembly 441 and a port headrope subassembly 442. The
former is composed of a single strap 443 twisted about axis of
symmetry 444 in a left-handed or counterclockwise direction, while
the port headrope subassembly 442 comprises a single strap 445
twisted about axis of symmetry 446 in a right-handed or clockwise
direction. Connection of the strap 443 with strap 445 is at
connection 447 in a vertical plane through the central axis 351'.
But the strap 443 connects with the upper starboard strapped bridle
377' at connection point 448, while the strap 445 connects with the
upper port strapped bridle 388' at connector 449 or equivalent.
[0212] Results of FIGS. 55 and 59 with regard to footrope
construction: force vectors are generated which spread the trawl
360, 360' and increase its volume relative to its central axis of
symmetry 351, 351', respectively.
[0213] Still further, FIGS. 56 and 60 also illustrate the cell
design of the invention in another aspect, say when used in the
constructing and using a frontrope assembly such as footrope
assemblies generally indicated at 450, 450' offset from the central
axis 351, 351' which result in spreading of the trawl and an
increase in volume.
[0214] FIG. 56 shows footrope assembly 450 in more detail. It
includes a starboard footrope subassembly 451 and a port footrope
subassembly 452 each composed of a pair of strands: subassembly 451
including strands 453, 454 and subassembly 452 comprising strands
455, 456. The subassemblies 451, 452 meet at connection 457 in a
vertical plane through the central axis 351. In detail, the strands
453, 454 are twisted about axis of symmetry 458 in a right-handed
or clockwise direction. On the other hand, the strands 455, 456 are
twisted about axis of symmetry 459 in a left-handed or
counterclockwise direction. Connection of the subassemblies 451,
452 with the upper starboard bridle 377 and upper port bridle 388
is at connector 460 or equivalent.
[0215] FIG. 60 shows headrope assembly 450' which includes a
starboard subassembly 461 and a port headrope subassembly 462. The
former is composed of a single strap 463 twisted about axis of
symmetry 464 in a right-handed or clockwise direction, while the
port headrope subassembly 462 comprises a single strap 465 twisted
about axis of symmetry 466 in a left-handed or counterclockwise
direction. Connection of the strap 463 with strap 465 is at
connection 467 in a vertical plane through the central axis 351'.
But the strap 463 connects with the upper starboard strapped bridle
at connection point 468, while the strap 465 connects with the
upper port strapped bridle 388' at like connector 468 or
equivalent.
[0216] Results of FIGS. 56 and 60 with regard to footrope
construction: force vectors are generated which spread the trawl
360, 360' and increase its volume relative to its central axis of
symmetry.
[0217] Final Operational Aspects
[0218] In order to use the cell constructed in accordance with the
invention, note that use in the field is particularized as to where
the cell is used within the trawl system of the invention, viz.,
with a towline, a trawl, or frontrope in the shape of a
breastlines, bridles, headrope or footrope.
[0219] That is, the method of field use includes the steps of
[0220] (i) from a vessel positioned at the surface of a body of
water, deploying first and second cell bars of a trawl system below
the surface of the body of water wherein a central axis offset from
the first and second cell bar means is established and the first
and second cell bar means have at least one interconnecting
connection therebetween,
[0221] (ii) establishing positional and directional integrity
between the shaped hydrofoil means associated with the first and
second cell bars relative to the central axis, and
[0222] (ii) propelling the shaped hydrofoil means of the first and
second cell bars whereby leading and trailing edges are established
therefor along with separate pressure differentials that provide
lift vectors relative to the central axis to increase cell
performance wherein said leading edge for the first cell bar when
normalized to a receding direction relative to the central axis,
always resides at a right side of the first cell bar as viewed in
the receding direction and wherein the leading edge of the second
cell bar when normalized to the same receding direction, reside
along a left side thereof as viewed.
[0223] Then with particular usage in association with a tow line,
the steps (i)-(iii) are modified as follows: Step (i) is further
characterized by the first and second cell bars being associated
with a tow line selected from one of a port and starboard tow line
and the at least one interconnecting connection therebetween is
established at the vessel itself; Step (ii) includes positioning
first and second strands comprising the hydrofoil means of the
first cell bar so that at least one strand thereof is positioned
along a first axis of symmetry offset from the central axis wherein
at least one of which is of a left-hand, loosely wound lay relative
to a receding direction established relative to the central axis
and positioning third and fourth strands comprising the said shaped
hydrofoil means of said second cell bar along a second axis of
symmetry so that at least one of which is of a right-hand, loosely
wound lay relative to the receding direction and the central axis;
and step (iii) includes the substep of increasing spread between
the port and starboard tow lines relative to the central axis to
gain increased cell performance. Instead of strands, straps can be
substituted as previously discussed.
[0224] Further, with particular usage in association with a trawl,
the steps (i)-(iii) are modified as follows: Step (i) is further
characterized by the central axis being longitudinally symmetrical
of the trawl and the at least one interconnecting connection being
established below the surface of the body of water; step (ii)
includes positioning first and second strands comprising the
hydrofoil means of the first cell bar so that at least one strand
thereof is positioned along a first axis of symmetry offset from
the central axis wherein at least one of which is of a left-hand,
loosely wound lay relative to a receding direction established
relative to the central axis, as well as positioning third and
fourth strands comprising the shaped hydrofoil means of said second
cell bar along a second axis of symmetry so that at least one of
which is of a right-hand, loosely wound lay relative to the
receding direction and the central axis; and in which step (iii)
includes the substep of increasing volume of the trawl relative the
central axis by the creation of the lift vectors to gain increased
cell performance. Instead of strands, straps can be substituted as
previously discussed.
[0225] Still further, with particular usage in association with a
frontrope, the steps (i)-(iii) are modified as follows: Step (i) is
further characterized by the central axis being longitudinally
symmetrical of a trawl to which the frontrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water; in which step (ii) includes
positioning first and second strands comprising the hydrofoil means
of the first cell bar so that at least one strand thereof is
positioned along a first axis of symmetry offset from the central
axis wherein at least one of which is of a left-hand, loosely wound
lay relative to a receding direction established relative to the
central axis, as well as positioning third and fourth strands
comprising the shaped hydrofoil means of said second cell bar along
a second axis of symmetry so that at least one of which is of a
right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (iii) includes the substep
of increasing volume of the trawl relative the central axis by the
creation of the lift vectors due to the frontrope to gain increased
cell performance. Instead of strands, straps can be substituted as
previously discussed.
[0226] Yet still further, with particular usage in association with
one of a pair of port and starboard bridles, the steps (i)-(iii)
are modified as follows: Step (i) is further characterized by the
central axis being longitudinally symmetrical of a trawl to which
the bridles attach and the at least one interconnecting connection
therebetween being established below the surface of the body of
water; in which step (ii) includes positioning first and second
strands comprising the hydrofoil means of the first cell bar so
that at least one strand thereof is positioned along a first axis
of symmetry offset from the central axis wherein at least one of
which is of a left-hand, loosely wound lay relative to a receding
direction established relative to the central axis, as well as
positioning third and fourth strands comprising the shaped
hydrofoil means of the second cell bar along a second axis of
symmetry so that at least one of which is of a right-hand, loosely
wound lay relative to the receding direction and the central axis;
and in which step (iii) includes the substep of increasing volume
of the trawl relative the central axis by the creation of the lift
vectors due to the selected pair of bridles to gain increased cell
performance. Instead of strands, straps can be substituted as
previously discussed.
[0227] Still further, with particular usage in association with a
headrope, the steps (i)-(iii) are modified as follows: Step (i) is
further characterized by the central axis being longitudinally
symmetrical of a trawl to which the headrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water; in which step (ii) includes
positioning first and second strands comprising the hydrofoil means
of the first cell bar means so that at least one strand thereof is
positioned along a first axis of symmetry offset from the central
axis wherein at least one of which is of a left-hand, loosely wound
lay relative to a receding direction established relative to the
central axis, as well as positioning third and fourth strands
comprising the shaped hydrofoil means of said second cell bar means
along a second axis of symmetry so that at least one of which is of
a right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (iii) includes the substep
of increasing volume of the trawl relative the central axis by the
creation of the lift vectors due to the headrope to gain increased
cell performance. Instead of strands, straps can be substituted as
previously discussed.
[0228] Yet still further, with particular usage in association with
a footrope, the steps (i)-(iii) are modified as follows: Step (i)
is further characterized by the central axis being longitudinally
symmetrical of a trawl to which the footrope attaches and the at
least one interconnecting connection therebetween being established
below the surface of the body of water; in which step (ii) includes
positioning first and second strands comprising the hydrofoil means
of the first cell bar means so that at least one strand thereof is
positioned along a first axis of symmetry offset from the central
axis wherein at least one of which is of a left-hand, loosely wound
lay relative to a receding direction established relative to the
central axis, as well as positioning third and fourth strands
comprising the shaped hydrofoil means of said second cell bar means
along a second axis of symmetry so that at least one of which is of
a right-hand, loosely wound lay relative to the receding direction
and the central axis; and in which step (iii) includes the substep
of increasing volume of the trawl relative the central axis by the
creation of the lift vectors due to the footrope to gain increased
cell performance. Instead of strands, straps can be substituted as
previously discussed.
[0229] From the foregoing, it will be appreciated that one skilled
in the art can make various modifications and changes to the
embodiments and methods within the spirit and scope of the claimed
invention as set forth below. For example, in retrofitting trawls
with the mesh cell of the invention, it should be appreciated that
the tensile strength of the mesh cell construction of the
invention, should be at least equal in strength to that of the
cells undergoing replacement. That means that if the mesh cell of
the invention is a composed of two product strands each
manufactured in accordance with conventional manufacturing
processes having a tensile strength S, the 2.times.S must be at
least equal to the tensile strength of the single strand that is
being replaced. In addition, the lengths of bridles and minibridles
used to tow upon the upper mouth edge and lower mouth edge of the
trawl, should be lengthened in order to maintain the proper angle
of attack of the trawl during operations, i.e., as there is an
incremental change in volume of the trawl, the bridles and
minibridles must be increased to maintain the proper angle of
attack.
[0230] Yet further, referring to FIG. 1, it is seen that
intermediate portion 28 of trawl 13 is made up of smaller size mesh
which may continue to decrease in size toward the aft of the trawl
13. Result: high drag components. It has been discovered that drag
can be significantly reduced using mesh cells comprising rather
loosely (not tightly) wound strands in a common direction. The
pitch of the turns in the aforementioned range 3d to 70d but
preferably are within a pitch range that results in a series of
cambered sections parallel (or closely parallel) to the axis of
symmetry of the trawl 13 being formed. Result: vibration and drag
are substantially reduced. Experiments show a reduction in drag in
a range of 30 to 50%. Further advantages: such mesh cells can be
constructed by conventional mesh making machines.
[0231] Additionally, to manufacture the cells, a process similar to
one associated with processing two-stand netting, can be used, with
modification as indicated below. E.g., a hook for handling the pair
of strands for knotting, is modified to after pick up, but before
knotting, the paired strands can be spun a certain number of
revolutions to provide the desired pitch of the mesh bar. The
direction of rotation is controlled so that the direction of twist
normalized to the hook, is opposite. There is also an equal
distance along the mesh bars measured from the knot. Hence the
pitch of each mesh bar will be essentially equal and the direction
of twist is opposite.
[0232] Further, machine produced mesh cells can be modified to
produce seines that have the following field capabilities. The mesh
cells of the invention are reproduced in full or intermediate
sections or areas throughout the seine. Such a construction in
whole or in part, permits the creation of composite forces say,
during pursing of the seine, causes diametrically opposite sections
of the seine to dive, lift and/or otherwise expand relative to
remaining sections or areas. Result: the volume of the seine is
surprisingly increased during such pursing operations in the field,
and the occurrence of excess billowing of the seine during such
operations, is significantly reduced.
[0233] The pitch of the bridle lines and the forward sections of
the frontropes may be longer than the pitch of the middle sections
of the frontropes and those cells making up meshes aft of the
forward sections of the frontropes.
* * * * *