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.

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]    [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]    [0035]FIG. 2 is another view of a trawl of FIG. 1 disconnected from the towing apparatus and vessel;  
         [0036]    [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]    [0038]FIG. 8 is a top view of the segment of FIGS.  4 - 7  after a counterclockwise twist has been applied;  
         [0039]    [0039]FIG. 9 is a top view of another segment produced from FIGS.  4 - 7  after a clockwise twist has been applied;  
         [0040]    [0040]FIG. 9 a  is top view of another work station for producing a torque-free segment;  
         [0041]    [0041]FIG. 9 b  is a top view of the segment of FIG. 9 a  after a counterclockwise twist has been applied but before release from the work station;  
         [0042]    [0042]FIG. 9 c  is a top view of the segment of FIG. 9 b  after release from the work station;  
         [0043]    [0043]FIG. 9 d  is a top view of a mating segment after a clockwise twist has been applied in the manner of the work station of FIG. 9 a;    
         [0044]    [0044]FIGS. 9 e  is a top view of first and second pairs of the segments of FIGS. 9 c  and  9   d  produced by the method of FIG. 9 a  placed in a X-pattern illustrating the formation of the mesh cell of the invention;  
         [0045]    [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]    [0046]FIG. 11 is a force diagram of hydrodynamic forces acting on the mesh cells of the invention in operation;  
         [0047]    [0047]FIG. 12 is a section taken along line  12 - 12  of FIG. 2,  
         [0048]    [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]    [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]    [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]    [0051]FIG. 15 a  is another top view of segments of FIG. 15 after a central knot and twisting thereof has occurred;  
         [0052]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [0061]FIG. 24 a  is a detailed akin to FIG. 24 showing an alternate mesh bar construction using braided (not twisted) strands);  
         [0062]    [0062]FIG. 24 b  is also a detailed akin to FIG. 24 showing a combination of braided and twisted strands;  
         [0063]    [0063]FIG. 24 c  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]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [0072]FIG. 32 a  is a fragmentary detail of another sub-headrope assembly of the trawl system of FIG. 32 illustrating another cell construction;  
         [0073]    [0073]FIG. 32 b  is a fragmentary detail of another sub-footrope assembly of the trawl system of FIG. 32 illustrating yet another cell construction;  
         [0074]    [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]    [0075]FIG. 34 is an enlarged detail taken along line  34 - 34  of FIG. 33;  
         [0076]    [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]    [0077]FIG. 36 is an enlarged detail taken along line  36 - 36  of FIG. 35;  
         [0078]    [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]    [0079]FIG. 38 is an enlarged detail taken along line  38 - 38  of FIG. 37;  
         [0080]    [0080]FIG. 39 is an illustrative side view of trawl system in accordance with the invention;  
         [0081]    [0081]FIG. 40 is a top view of the trawl of the trawl system of FIG. 39 disconnected from the towing vessel;  
         [0082]    [0082]FIG. 41 is a fragmentary enlargement of a mesh cell of the trawl of FIG. 40;  
         [0083]    [0083]FIG. 42 a  is a section taken along line  42   a - 42   a  of FIG. 40;  
         [0084]    [0084]FIG. 42 b  is a detail section akin to FIG. 42 a  showing an alternative embodiment;  
         [0085]    [0085]FIG. 42 c  is a detail section akin to FIG. 42 a  showing another alternative embodiment;  
         [0086]    [0086]FIG. 42 d  is a detail view-slightly enlarged-of alternate connector for the mesh cell of FIG. 41;  
         [0087]    [0087]FIG. 42 e  is a section taken along line  42   e - 42   e  of FIG. 42 d;    
         [0088]    [0088]FIG. 43 is a section taken along  43 - 43  of FIG. 40;  
         [0089]    [0089]FIG. 44 is another fragmentary enlargement of an alternative mesh cell of the invention;  
         [0090]    [0090]FIG. 45 is a section taken along line  45 - 45  of FIG. 44;  
         [0091]    [0091]FIG. 46 is yet another fragmentary enlargement of another alternative mesh cell of the invention;  
         [0092]    [0092]FIG. 47 is a section taken along line  47 - 47  of FIG. 46;  
         [0093]    [0093]FIG. 48 is a section taken along line  48 - 48  of FIG. 46;  
         [0094]    [0094]FIG. 49 is a section taken along line  49 - 49  of FIG. 46;  
         [0095]    [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]    [0096]FIG. 51 is a fragmentary enlargement of yet another alternate mesh cell of the invention;  
         [0097]    [0097]FIG. 52 a  is a detail view of an alternative connection for the mesh cell of FIG. 51;  
         [0098]    [0098]FIG. 52 b  is a section taken along line  52   b - 52   b  of FIG. 51 a;    
         [0099]    [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]    [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]    [0101]FIG. 55 is a fragmentary side view of the embodiment of FIGS. 53, 54;  
         [0102]    [0102]FIG. 56 is a fragmentary top view of the embodiment of FIGS. 53, 54;  
         [0103]    [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]    [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]    [0105]FIG. 59 is a fragmentary side view of the embodiment of FIGS. 57, 58; and  
         [0106]    [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]    [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  30   a  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]    [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  42   a . 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  49   a , the loop  42  becomes twisted to form a counterclockwise lay segment  50  of thread  35 , wherein segment  50  has a length L 1  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 L 1  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. 9 a.    
         [0116]    As shown in FIG. 9 a , 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  48   a  of the spindle  48  as shown in FIG. 9 b . 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  57   a  (such as used in removing torque in fishing lines and purchasable at any sporting goods store) and thence through a second residual strand  57   b  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  57   b  attached thereto, are not so wound because of the action of the barrel swivels  57   a . 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  48   a  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  59   a  having a length L 1  and a pitch Po in the range precisely(?) set forth above, as shown in FIG. 9 c . That is, a segment  59   a  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  59   b  of FIG. 9 d  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  59   c  and  59   d  which can then be assembled together in a X-pattern as shown in FIG. 9 e.    
         [0117]    [0117]FIG. 9 e  shows a X-pattern layout of pairs of segments  59   a - 59   d  produced by the method of FIGS. 9 a  and  9   b.    
         [0118]    As shown, a pair of left-handed or counterclockwise segments  59   a ,  59   c  (each constructed as depicted in FIG. 9 c  and positioned parallel to each other) is located in the aforementioned X-pattern along with a pair of right-handed or clockwise segments  59   b ,  59   d  (each constructed as depicted in FIG. 9 d  and positioned parallel to each other). The segments  59   a - 59   d  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  59   a ′,  59   b ′,  59   c ′ and  59   d ′. Note that the two mesh bars or sides of the cell  58  associated with sub-segments  59   b ′,  59   d ′ 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  59   a ′ and  59   c ′ 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  59   a ′ and  59   b ′ diverge from a common intersection point B′ and leading and trailing edges are established for each of the sub-segments  59   a ′ and  59   b ′ wherein the leading edge for the sub-segment  59   a ′ when normalized to the receding direction arrow A′ relative to the central axis  32 ′, reside at a right side of the sub-segment  59   a ′ as viewed in the receding direction arrow A′ and wherein the leading edge of the subsegment  59   b ′ when normalized to the receding direction arrow A′, reside along a left side of the sub-segment  59   b ′ as viewed in the receding direction as indicated by arrow A′. Similarly, for the sub-segments  59   c ′ and  59   d ′ converging toward common intersection point B″, leading and trailing edges are established for each of the sub-segments  59   c ′ and  59   d ′ wherein the leading edge for the sub-segment  59   c ′ when normalized to the receding direction arrow A′ relative to the central axis  32 ′, reside at a right side of the sub-segment  59   b ′ as viewed in the receding direction arrow A′ and wherein the leading edge of the subsegment  59   d ′ when normalized to the receding direction arrow A′, reside along a left side of the sub-segment  59   d ′ 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]    [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  30   a  of the cell  30  to be formed. That is, the segment  50  is positioned such that its end  43   a  is offset a distance D 1  above the axis of symmetry  30   a , while end  43   b  is offset a distance D 1  below the axis of symmetry  30   a . And the segment  51  is positioned such that its end  52  is offset a distance D 1  below the axis of symmetry  30   a  and its other end  53  is positioned above the axis of symmetry  30   a . 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  30   a . That is, the end  53 ′ of clockwise twisted segment  51 ′ overlays end  43   a  of counterclockwise segment  50  and is thus, offset a distance D 1  above the axis of symmetry  30   a . Similarly, end  52 ′ of the segment  51 ′ is offset a distance D 1  below the axis of symmetry  30   a . In similar fashion, end  43   b ′ of counterclockwise twisted segment  50 ′ overlays end  52  of clockwise twisted segment  51 , and thus, is offset a distance D 1  below the axis of symmetry  30   a . Similarly, the end  43   a ′ of counterclockwise twisted segment  50 ′ is positioned a distance D 1  above the axis of symmetry  30   a.    
         [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  30   a  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  30   a  and terminates at the intersection of pair ends  43   b ′,  52 , a distance D 1  below the axis of symmetry  30   a . While, mating clockwise twisted mesh bar  61  starts at intersection  55 ′, diverges transversely outward relative to the axis of symmetry  30   a  and terminates at the intersection of pair ends  43   a ,  53 ′ a distance D 1  above the axis of symmetry  30   a.    
         [0124]    Clockwise mesh bar  62  starts at the intersection of pair ends  43   b ′,  52  a distance D 1  below the axis of symmetry  30   a , diverges transversely inwardly relative to the axis of symmetry  30   a  and terminates at the intersection  55 . While, mating counterclockwise twisted mesh bar  63  starts at the intersection of ends  43   a ,  53 ′, diverges transversely inward relative to the axis of symmetry  30   a  and terminates at the intersection  55  coincident with the axis of symmetry  30   a.    
         [0125]    Thereafter, the mesh bars  60 ,  61 ,  62 ,  63  can be permanently attached together at intersections  55 ′,  55  and at pair ends  43   a ,  53 ′ and  43   b ′,  52  via couplers not shown that are conventional in the art, such as bindings, seams, braids, metallic bands or the like, or the ends  43   a ,  53 ′ and  43   b ′,  52  may be joined to one another.  
         [0126]    Note that for the mesh cell  30 , a longitudinal working plane P 1  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 P 2  normal to the longitudinal working plane P 1 , such working plane P 2  passing through centroid C, such centroid being positioned coincident with the axis of symmetry  30   a  of the cell  30 . For the quadratic mesh cell  30 , as shown, the transverse working plane P 2  passes through paired ends  43   b ′,  52  and  53 ′,  43   a . Such working plane P 2  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 P 2 . 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  30   a  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  43   a ,  53 ′ and  43   b ′,  52  and terminating at intersection  55  coincident with the axis of symmetry  30   a . That is, the mesh bar  62  begins at the ends  43   b ′,  52  coincident with the transverse working plane P 2  and is twisted in a clockwise direction; and the mesh bar  63  begins at the ends  43   a ,  53 ′ also coincident with the transverse working plane P 2  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 ′,  43   a  and  43   b ′,  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]    [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 P 1  previously mentioned wherein the plane P 1  passes through the common longitudinal axis of symmetry  30   a  of the mesh bars  60 ,  61 ,  62  and  63 . At the intersection of plane P 1  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  30   a  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 P 1  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 P 1 .  
         [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  30   a  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 P 1  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  77   a  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  77   a ′ of the bottom panel  77 ′ defines a longitudinal plane P 6  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]    [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  50   a ,  50   b  and  51   a ,  51   b  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. 15 a , at the central point  80 . Thereafter, the subsegments are twisted about central axes  88   a ,  88   b  to provide the orientation depicted in FIG. 10. That is, the subsegments  50   a ,  50   b  are twisted to form a counterclockwise lay direction as viewed from exterior end segment  84   a  of subsegment  50   a . Likewise, the subsegments  51   a ,  51   b  are twisted to form a clockwise lay direction as viewed from exterior end segment  84   b  of subsegment  51   a.    
         [0140]    [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  50   a ′,  50   b ′ and  51   a ′,  51   b ′ 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]    [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  50   a ″,  50   b ″ and  51   a ″,  51   b ″ 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]    [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  50   a ′″,  50   b ′″ and  51   a ′″,  51   b ′″ wherein subsegment  50   a ′″ is integrally united with subsegment  51   a ′″ and subsegment  50   b ′″ is integrally united with subsegment  51   b ′″ 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]    [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  50   a ″″,  50   b ″″ and  51   a ″″,  51   b ″″ wherein subsegment  50   a ″″ is integrally united with subsegment  51   b ″″ and subsegment  50   b ″″ is integrally united with subsegment  51   a ″″ 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]    [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  50   a ′″″,  50   b ′″″ and  51   a ′″″,  51   b ′″″ wherein subsegment  50   a ′″″ is integrally united with subsegment  51   a ′″″ and subsegment  50   b ′″″ is integrally united with subsegment  51   b ′″″ 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]    [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  50   a ″″″,  50   b ″″″ and  51   a ″″″,  51   b ″″″ wherein subsegment  50   a ″″″ is integrally united with subsegment  51   a ″″″ and subsegment  50   b ″″″ is integrally united with subsegment  51   b ″″″ 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]    [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  50   a ′″″″,  50   b ′″″″ and  51   a ′″″″,  51   b ′″″″ formed in a X-pattern about braided or woven intersection segments  113  formed by opening up strands  114 ,  115  of subsegments  50   a ′″″″,  50   b ′″″″ and passing subsegments  51   a ′″″″,  51   b ′″″″ therethrough, then opening up strands  114 ,  115  of subsegments  51   a ′″″″,  51   b ′″″″ and passing subsegments  50   a ′″″″ and  50   b ′″″″, therethrough. Thereafter, each subsegment is twisted as previously indicated above. Note that the load bearing capability of subsegments  51   a ′″″″ and  51   b ′″″″ are maximal.  
         [0147]    [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  119   a ,  119   b ,  119   c  and  120   a ,  120   b ,  120   c . These sub-strands  119   a - 120   c  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  119   a - 119   c  and sub-stands  120   a - 120   c  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 V 5  is created in addition to usual vector force V 6  created by water passage through grooves  121  between the sub-strands  119   a - 120   c.    
         [0148]    [0148]FIGS. 24 a - 24   c  illustrate variations in the construction of the strands  119 ,  120  of segment  117  of FIG. 24. In FIG. 24 a , the strands  119 ′,  120 ′ are twisted in a right-handed or clockwise direction about axis of symmetry  117   a  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  117   a.  In FIG. 24 b , 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  117   b , as shown in FIG. 24. While strand  120 ″ is formed of a braided construction as hereinbefore described with reference to FIG. 24 a . In FIG. 24 c , 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  117   c  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  117   c.    
         [0149]    [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]    [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 V 8  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 P 8 . While the corner knots  140  are longitudinally spaced a common longitudinal distance D 4  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 P 7  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 V 9  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  157   a - 157   f . The mesh bar  151  includes first and second strands  158 ,  159  which are twisted in a counterclockwise direction when viewed from braided intersection  157   a . The mesh bar  152  also includes first and second strands  158 ,  159  which are twisted in a clockwise direction when viewed from braided intersection  157   a . Mesh bars  153 ,  154  also includes first and second strands  158 ,  159  which are twisted in a clockwise direction when viewed braided intersection  157   b  or  157   c . Mesh bar  155  also includes first and second strands  158 ,  159  which are twisted in a counterclockwise direction when viewed from braided intersection  157   d . And mesh bar  156  also includes first and second strands  158 ,  159  which are twisted in a clockwise direction when viewed from braided intersection  157   e . 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]    [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  167   a  and a right-hand lay sub-headrope  167   b , and (iii) footrope  169  comprising right hand lay sub-footrope  169   a  and left-hand lay sub-footrope  169   b  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]    [0161]FIGS. 32 a  and  32   b  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. 32 a , a detail of sub-headrope  167   a ′ 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  167   a ′. Note that the mate of the sub-headrope  167   a ′ would have a similar construction as the latter but with opposite winding as that shown.  
         [0162]    In FIG. 32 b , a detail of sub-footrope  169   a ″ 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  169   a ′. Note that the mate of the sub-footrope  169   a ′ would have a similar construction to the latter but with opposite winding as that shown.  
         [0163]    Still Further Aspects  
         [0164]    [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]    [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]    [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]    [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]    [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 D 1  and a second strand  251  of diameter D 2  where D 2 =½ D 1 . As previously explained, the first strand  250  has an outer surface  252  defining the aforementioned diameter D 1 , 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]    [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]    [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  270   a , and frontropes  271  that include breastlines  271   a , headropes  271   b  (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  274   a  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]    [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  274   a  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. 42 a ,  42   b  and  42   c , the cross section of each strap  284  is seen to be basically rectangular. In FIG. 42 a , the twisted strap  284  includes rounded short sides  284   a  and parallel long sides  284   b  with the leading and trailing edges occurring at the short sides  284   b  alternating between the former and the latter based on the pitch, as explained below. In FIG. 42 b , 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  290   a  of the oval side wall  290 . In FIG. 42 c , 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  297   a  of the two strands  297  have tangential contact with each other as well as inner surface  295   a  of the oval side wall  295 .  
         [0181]    [0181]FIG. 42 d  shows an alternate connection  285 ′ in which the long sides  284   b ′ 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. 42 e . The seams  298  are parallel to short sides  284   a′.    
         [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]    [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  304   a  (exterior relative to the central axis  281  of the trawl) is preferably cambered relatively more than the near long side  304   b . As a result, lift vector  307  is provided. In addition, the short sides  305  can be rounded at corners  305   a . The ratio of width W to thickness T of the strap  303  is as set forth supra.  
         [0185]    [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  308   a  (exterior relative to the central axis  281  of the trawl) is preferably cambered relative to uncambered near long side  308   b , 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  309   a . 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]    [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  312   a  and short side surfaces  312   b  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]    [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  308   a ′,  308   b ′ have been folded into two plies. A series of seams  315  provide for such attachment. The seams  315  are parallel to short sides  309   a ′,  309   b′.    
         [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]    [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  331   a  (that aids in defining the resulting cell  334 ) is offset a distance D 1  above axis of symmetry  335  while end  331   b  is offset a distance D 1  below the axis of symmetry  335 . The segments  332  are positioned (relative to the cell  334 ) so that an end  332   a  is offset a distance D 1  below axis of symmetry  335  while end  332   b  is offset a distance D 1  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]    [0194]FIG. 52 a  and  52   b  show alternate details of a connection  334 ′ in which the long sides  338   a  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  338   b.    
         [0195]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [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]    [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×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.