Volume 019
Article 17
State of Idaho
DEPARTMENT OF FISH AND GAME
Ross Leonard, Director
.
NET REPAIR MANUAL
by
Stacy V. Gebhards
Fisheries Biologist
1960
TABLE OF CONTENTS
Page
Introduction ....................................................... 1
Trimming ........................................................... 1
Weaving ............................................................ 4
Shuttle ....................................................... 4
Knots ......................................................... 4
Section Replacement ............................................... 12
Hanging ........................................................... 15
Hanging basis ................................................ 15
Hanging on supporting lines .................................. 15
Hanging on hoops ............................................. 16
Maintenance of Nets ................................................ 19
Nylon ........................................................ 19
Other synthetics ............................................. 20
Bibliography ...................................................... 21
LIST OF FIGURES
Figure
1.
Page
Trimming ................................................ 2
2.
Hole trimmed and ready for weaving ...................... 3
3.
Shuttle or knitting needle .............................. 5
4.
Sequence of knots in weaving ............................ 6
5.
Starting knot ........................................... 7
6.
Half-mesh knot left to right ............................ 8
7.
Sider knot on the right
8.
Pick-up knot right to left .............................. 9
9.
Half-mesh knot right to left ........................... 10
10.
Sider knot on the left ................................. 10
11.
Pick-up knot left to right ............................. 11
12.
Finishing knot ......................................... 11
13.
Two variations of the "knot-and-a-half" used
in hand-tying nylon nets ............................... 11
14.
Procedure in section replacement ....................... 13
15.
Procedure in seaming .................................... 14
16.
Net hung on a 1/3-basis ................................ 16
17.
Net hung on a 1/2-basis ................................ 16
18.
Procedure in hanging nets on a line .................... 17
19.
Procedure in hanging nets on a hoop .................... 18
................................ 8
INTRODUCTION
Although most nets today are machine tied and are purchased ready-made
from various companies, net repairs must still be done by hand. A properly
mended net can mean the difference between catching many fish or none at all.
The intent of this manual is merely to acquaint the beginner with the proper
procedure in net mending. Proficiency in mending can come only through practice.
The techniques described in this manual are essentially those which are
used by commercial fishermen in the Illinois River Valley with some modifications by the author.
TRIMMING
The first step in mending a net is to trim the hole so that it may be
rewoven in one continuous operation. Each knot in the webbing has 4 unbroken
strands (quarter meshes) leading away from it. Around the edges of a tear or
hole in a net, you will find knots with only 1, or 3 unbroken strands leading away from it. The correct procedure for trimming is as follows (Figures
1 and 2):
1.
Start at the top of the hole and leave one knot with 3 unbroken
strands. This will be the starting point for the reweaving.
2.
Work down one side of the hole, knot by knot. Hereafter, when finding
a knot with 3 unbroken strands, cut out the lower strand. Knots with 2 or 4
unbroken strands are left as they are.
3.
Trim down one side to the bottom and then trim the other side.
One knot at the bottom is left with 3 unbroken strands. This will be the
last tie in the weaving.
4.
The hole is now ready for weaving. Each knot around the edge of the
hole should have 2 or 4 unbroken strands, except the starting point at the top
and the finishing point at the bottom.
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WEAVING
Shuttle
The twine used for weaving is wound on a shuttle or knitting needle
(Figure 3 ) . These are made of metal, plastic, or hard wood such as oak,
hickory, ash, or osage orange. The shuttle is filled by passing the twine
beneath the tongue, around the notch at the bottom, up and beneath the
tongue from the opposite side. This is continued until the shuttle is
filled.
Knots
The basic knot used in heavy net construction is the sheet bend, also
known as the weaver's knot, jam hitch, common bend, single knot, and netter's
knot. Gill nets which utilize synthetic threads in construction (nylon, orlon,
dacron, etc.) require special knots to prevent slippage. Carrothers (1957)
describes some of these special knots used in machine-tied and hand-tied nets.
Two non-slip knots for nylon are shown in Figure 13.
Figure 4 illustrates the complete sequence of knots used in weaving with
the details of the knots shown in Figures 5 through 12. Knake (1947) describes
variations in the knitting sequence as practiced in New England.
When weaving from left to right, the shuttle is brought up through the
mesh. This also holds true for sider knots. When weaving from right to left,
the shuttle is passed down through the mesh.
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-8-
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SECTION REPLACEMENT
Occasionally it is necessary to replace a section rather than reweave
a large hole. The damaged section is cut out and replaced with a new section
as shown in Figure 14. The starting knot and finishing knot begin and end at
a 3-strand knot. The remaining knots along the edges are all 2 and. 4-strand
knots (Figure 15). The procedure for seaming is as follows:
The section removed should be trimmed so that each edge of the hole
is straight and includes only one continuous row of meshes (Figure 14B).
The new section to be replaced in the hole (Figure 14c) should be
cut to the same depth of the hole and. 2 meshes less in length than were
present in the original section. Each seam fills in the space of one row of
mesh, and. the replacement section must be cut one mesh less than the hole at
each seam.
Figure 15 shows the sequence of knots used in seaming. As in mending,
the strands are gaged with the fingers. Note that the beginning and finishing
ties are half-meshes while the intervening ties are all quarter-meshes.
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HANGING
Hanging Basis
The fullness of a net is determined by how spread out or how closely
bunched the meshes are when attached to the supporting lines. A net hung
on a 1/3-basis means that 3 meshes are hung in the space of 2 stretched
meshes. A net hung on a 1/2-basis moans that 4 meshes are hung in the space
of 2 stretched meshes (Figures 16 and 17).
Another means of determining the basis is to measure the length of the
stretched meshes per foot of supporting line. A net hung on a 1/3-basis
contains 18 inches of stretched meshes per foot. A net hung on a 1/2-basis
contains 21i. inches of stretched meshes per foot.
One-fourth (1/4) basis .......................... 16 in/ft
One-third (1/3) basis ........................... 16 in/ft
Two-fifths (2/5) basis .......................... 20 in/ft
Three-sevenths (3/7) basis ...................... 21 in/ft
One-half (1/2) basis . .
e ............................... e .................................... 24
Five-ninths (5/9) basis
in/ft
27 in/ft
Three-fifths (3/5) basis
. . 30 in/ft
Gill nets are usually hung on a 1/2-basis. Seines, hoop nets, and dip
nets are hung on a 1/3-basis.
Hanging on Supporting Lines
The following procedure is used in rehanging gill nets and seines:
1.
Run the shuttle through three (1/3-basis) or four (1/2-
basis) meshes, depending upon the basis to be hung (Figure 18A).
2.
Measure off a distance of 2 stretched meshes on the
supporting line (Figure 18A).
-15-
3. Tie a clove hitch on the supporting line at this point (Figure
18B-D).
Hanging on Hoops
Hoop net webbing is hung on a 1/3-basis, and each individual mesh is
tied to the hoop. This is accomplished with a clove hitch as shown in
Figure 19.
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MAINTENANCE OF NETS
With the advent of synthetic fibers such an nylon, terylene or dacron,
orlon, vinyl, and rayon, many of the problems of rotting and preservatives
associated with cotton and linen nets have been eliminated. However, a
certain amount of care and use of preservatives are necessary to insure
maximum life from synthetic-fiber nets. Synthetics have not as yet completely
replaced natural fibers, and information concerning the application of
copper and creosote-base preservatives can be obtained from various sources
listed in the bibliography.
Nylon
U
U
Sunlight is probably the most detrimental and extensive factor in the
weakening of nylon nets. Tests have shown that nylon breaks down in sunlight
twice as fast as linen or cotton (Carrothers, 1957). Care should be taken
to protect nylon from direct sunlight during storage and handling. Net dips
are available for nylon and other synthetics which contain a special compound
designed to screen out sunlight. These can be purchased in heavy and. light
viscosities currently for about $1.25 per gallon. The heavy viscosities are
used on nets which require a heavy physical coating to reduce abrasion.
Although bacteria in fish slimes cannot affect nylon, slimes may create
acidic conditions which will damage nylon. Carrothers (1957) recommends
dipping nylon gill nets in a 2 per cent bluestone (copper sulphate) solution
long enough to remove the slime and then washing in clean water to remove
the bluestone before drying. Strong bluestone solutions or bluestone left
on a net can reduce the wet mesh strength and should be avoided.
Other factors which are known to damage nylon are chlorine and oxidizing
bleaches and drying oils, such as linseed oil.
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Other Synthetics
Many synthetics are damaged by sunlight, but to a lesser degree than
nylon. Orlon is highly resistant to sunlight. Dacron is resistant to acids
but is damaged by alkaline conditions. Excessive heat will affect the tensile
strengths and elasticity of synthetic fabers.
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BIBLIOGRAPHY
Anonymous.
Commercial fishermen's guide. St. Louis. Adams Net and. Twine Co.
1947. How to make and mend fish nets. U.S.F. W.S. Fishery Leaflet 125.
Carrothers, P.J.G.
1 9 5 7 . The selection and care of nylon gill nets for salmon. Vancouver, B.C.
Fish. Res. Board of Can., Indust. Memo. No. 19.
Coker, Coit M.
1914 9. Maryland's commercial fishing gears. I-the fin-fish gears. Solomons
Island, Md. Board of Nat. Res., Dept. of Research and Educat., Educat.
Series, No. 18.
Conn, W.T.
Net preservative treatments. Chicago. Commercial fishermen's reference
book. R.J. Ederer Co.
Firth Frank E. and Carl B. Carlson
1949. Preservation and care of fish nets. U.S.F. W.S. Fishery Leaflet
66.
Knake, Boris O.
1 9 4 7 . Methods of net mendingrNew England. U.S.F. W.S. Fishery Leaflet
241.
Ludgate,H.T.
1948. Popular netcraft. Toledo, Ohio. Netcraft Co.
Sundstrom, Gustaf T.
1957. Commercial fishing vessels and gear. U.S.F. & W.S. Circ.
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48.