New England Trawl Net Designs - Gearnet Trawl NetDeisgns.pdfNew England Trawl Net Designs In...
Transcript of New England Trawl Net Designs - Gearnet Trawl NetDeisgns.pdfNew England Trawl Net Designs In...
New England Trawl Net Designs
In Fulfillment of FMT 591 Directed Research
The New England fisheries have relied upon two gore - (two seam) trawl nets,
however, these designs have had major changes to the panial three seam or semi
balloon trawls in the 1940s. The Atlantic Western Trawl or box trawl developed in
the 1960s and was modified for West Coast fisheries (Fisher 1972) and it was a four
seam - four gore trawl net plan- Model IV-A
The box or four seam trawls have certain advantages as to their ability to
incorporate square meshes for discard escape. At present, four seam trawls are not
used for various reasons- higher cost - more labor - more time in repairing and
replacing sections, and lack of appropriate size models for test tank display.
A working model of an Atlantic Western Trawl net is currently proposed by Larry
Fuller, a student in the two year fisheries program. A four seam trawl may offer
certain advantages for discard study.
Additional research on trawl net design is suggested.
Rekeyed Sound School Adult Education, October 2011 For copies contact Susan Weber at [email protected]
Submitted to: Mr. Alben J. Hillier Dr. John C. Sainsbury
Dept. of Fisheries, Wickford, RI
By Timothy C Visel
Department of Fisheries & Marine Technology UNIVERSITY OF RHODE ISLAND - May 1980
Early Beam And Otter Trawl Net Plans & Diagrams
Dandy--+
DETAIL AT TRAWL HEAD
Foot-Rope QUdrter-Rope
~Belly " (und.'....lh)
Pocket PLAN .VIEW
Fig. 69. Beam trawl showing method of construction and side view of traw/head.
Codt:nd.
"-...... Botings ~ (A&OVE)
Bqlly. (UNDERNEATH.)
Squarez.Headlln<z
Floats.
Low (l r W;n9
·t·········.... Tickl~r Chain.
Hczadlln<Z.
Bosom PI~ccz.
Laccdridgc q~arter Ropcz.tTowing Warp.
Fig. 70. Otter trafvl. Although fishing skippers alter their trawls according to their own ideas, and for different purposes, variations can be referred to the type shown here.
From "An.Acc~u~t Of The Fishing Gear ..Qi England And Wales" F.M. DaV1S Mlnlstry of Agriculture, Fisheries And Food. London: Her }~jesty;s Stationary Office 1923.
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Preface
The modern trawl is one of the most important and effective active fishing
method used in present day fisheries. Its origin can be traced to Europe where
it was developed from drags and dredges and generally had a conical bag-like shape
with a supporting beam at the "trawl Head"{see diagrams). These nets became known
as "Beam Trawls" and were very effective in capturing demersal fish such as flounder.
The beam trawl soon proved to be rather cumbersome and its efficacy depended
upon the size of the fishing vessel itself. Otter trawls using otter boards re
palces the awkward beam trawls. Successful modern otter trawling operations were
underway in Denmark and England around the turn of the 19th century.
The introduction of the beam and otter trawls into New England developed our
groundfisn fisheries. Each trawl has its own distinct construction pattern or net
plan. Since their int~oduction trawl net plans show how trawl net designs have
progressed. Fully understanding these different trawls, with respect to design
advantages or disadvantages, should show how modern trawls developed.
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Early Beam And Otter Trawl Net Plans & Diagrams
SqUARE
At-------IB a
A E
B e
" 0I'
/ I,,
R c BOTTOM COD-END
t'
h
I~ig. 71. Plan of Beam trawl. A. Back. B. DeIly.
Fig.' 72. Plan of Otter trawl. A. Back. B. Belly.
T
A
m, ,, \ I
. n\...{p w··}
d C BOTTOMB COD-END
E F e, r
From "An Account Of The. Fishing Gear Of England And \~ales"
F.M. Davis Ministry of Agriculture, Fisheries And Food. London: Her Majesty's Stationary Office 1923.
3 I
Abstract
Although the modern trawl is one of the most important and effective active
commercial fishing method~,it has evolved only recently. Its origin can be traced
to Europe where it developed into a distinct type of fishing gear. Subsequent design
changes have influenced trawl net plans or pattern thoughout the world. Researching
the design concepts of some unique early trawls may help to explain how trawl net
designs have progressed since their introduction into New England. Investigating
early trawl designs would also provide fishermen and other interested parties with
a cohesive history of how some trawl net designs have evolved in respect to inherent
advantages or disadvantages.
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Introduction
By all acoounts, the modern bottom trawl originated in Europe and was de
veloped from a much more primitive device. According to F.M. Davis, (The Fishing
Gear Of England And Wales. 1923) the "trawlll probably originated from an oyster
dredge or seine. Davis used as his explanation of the history of trawls, an article
from the Fish Trades Gazette (1921). It states that as early as 1376 Engli~h oyster
men were complaining about the use of a "wondyrchoun" which was used for fishing
but at the same time gathering oysters. Davis decribes the wondyrchoun as "it was
three fathoms long and tern of men's feet wide, ant the net has a beam of wood ten
feet long at the of which were two frames formed lick a cole rake; that a leaded
rope weighted with many great stones was fixed on the lower part of the net between
the two frames; ant that another rope was fixed with nails on the upper part of the
beam, so that the fish entering the space between the beam and the lower net were
caught. The net had meshes (maskes) of the length and breadth of two men's thumbs".
Davis further states that "It is also known that trawling must have existed in Flanders
in the fifteenth century as it was prohibited in 1499, the prohibition being renewed
in 1509 and 1594. The reasons for the Flanders prohibition and the petition against
the wondyrchoun were the smae as those that continue to crop up even in modern times
(1923)t namely scraping up the bottom and destruction of shelter, food, spawn and fry
of fish.
Eventually, this early conical net with a wide mouth kept open by a fixed rigid
beam of timber developed into a well defined gear type commonly referred to as a "beam
trawl". The beam trawl is considered the first true "trawl" as a distinct fishing
gear. The design of the beam trawl consists of two tapered 11bellys" (top & bottom),
one "square". (rectangular section), two tapered lower "wings", and a "cod end".
The bottom panel contains the bottom as lower wings, bottom belly, and bottom section
of the cod end. Once these two panels are completed they are then 1lgoredt1 together
forming a conical bag of webbing. The lower wings are attached to the trawl heads,
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the bottom belly was hung to a "footrope" and the square was attached directly to
the beam. The wooden beam was supported by angular, iron, trawl heads. The distance
between the beam and footrope depended upon the height of these trawl heads. The
beam trawl would prove to be rather cumbersome and the length of the fishing vessel
became a limiting factor on the size of the beam trawl used. Fishermen needed a
trawl that had no restrictions on the length of the vessel. For example, a 30 foot
smack could not tow a 50 foot beam trawl. The "otter trawl", developed around the
turn of the century, utilized "otter doors" or otter'· boards to ~eep the now free
wings apart when the trawl was being towed. F.M. Davis credited the development of
the otter board to Irish fishermen, who used a similar device on the surface of lakes
and streams to catch trout and salmon. These surface otter boards were designed to
"sheer away from the boat on the quarter" enabling a line to be kept taut. Lines
were then attached to this line with flys and lures used for trolling trailing off
them. The action and appearance of these surface boards no doubt looked like or
acted like otters swimming through the water. Today, trawl doors are attached to
the wings of a trawl to provide the spreading force needed to the keep the mouth
open, allowing the fish to enter the belly section of a trawl. The otter trawl soon
proved to be efficient and profitable. The large, hard to handle beam trawls, were
quickly discarded for the larger, yet less awkard otter trawl.
Today generally, a trawl net is described as a funnel shaped device constructed
of net "webbing" that is towed along the sea floor behind the fishing vessel. A net
of this design requires a steady, strong, pull to the "wings ff spread apart and guide
the fish past the "bellys" and finally into the "cod end".. The trawl net consists
of many sections and distinct parts; the headrope, main body (bellys) cod end, sweep
(footrope) and wings. Floats are attached to the headrope keeping the net open
allowing fish to enter while the sweep is in close contact with the sea bottom.
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New England Trawls
When New England fishing vessels depended on sail for propulsion, beam trawls
were fished with success. It soon became apparent however, that New England trawlers
outfitted with a steam engine enjoyed a decided advantage over sail powered vessels.
In Europe, after the development of the stearn engine and later maine engines such
as diesels, "otter trawling" soon displaced the earlier methods of fishing such as
hand line, seines, and long line dories!i.used by offshore fishing schooners. With the
extra power required to tow otter trawls and their doors, European fishermen experi
mented with various rigging techniques. The transition from beam trawls to otter
trawls, at the turn of the century, occurred slowly in New England. In Europe
however, traditional beams trawls were raidly replaced with the "fly backed beam
trawl",. In this modification of the beam trawl, the square is reduced with the
addition of two "top wings", The square is no longer attached to the beam, but
hung on a section of rope called the "headrope", The top wings are also hung to
the headrope which is now attached to the iron trawl heads. The beam was next
replaced with doors creating the first otter trawl. In New England, several trawl
net designs were being ua~~ also experimented with during this period. These designs,
no doubt, originated from individual construction techniques. It would be virtually
impossible to follow the exact development of New England trawl net designs. It
is possible however to follow the basic design changes that occurred as New England
fishermen first started trawling.
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Beam Trawls
The first trawls used in New England were the beam trawls. A sample beam
trawl net plan helps show the basic design principals. The plan of a beam trawl for
a forty foot smack is typical fa the type and size used in New England. This type
of beam trawl was popular around the turn of the century (see diagrams).
Flounder Drags
A flounder drag is a very primitive trawl. Originally a flounder drag, or
flounder gore, was a tapered section of webbing that was folded and gored to form
a cylinder. This single gore was placed on top and two rectangular wings were
attached at each edge of web cylinder. This early trawl had no apron or "overhang",
the usual function of the square. By the late 1920's this single gore drag lost
much of its popularity, (American Linen Thread Manual 1928). The two gore flounder
drag became popular in the 1930's and 1940's with variations still existing today.
they are similar to the one gore trawls although the top and bottom bellys are
gored up to the beginning of the wings as with the single gore drags the gore
ends.
Flat Nets
Flat nets are very similar to the flounder drags. The wings are rectangular
but are gored together for the entire lengbh of the trawl. Small triangular sections
are joined to the wing and belly section as with the two gore flounder drags. A
small between the triangular corners and the top belly. The difference between
the cut out section of the bottom belly and the hand knit section of the top
belly creates the roof or overhang. These trawls are still used in many areas of
New England primarily from small boats. The design, no doubt, is a very old one.
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Nantucket. Trawl
The "Nantucket Trawl" is again similar to the early flat and flounder trawls.
The Nantucket trawl consists of a top and bottom belly, two wings and four triangu
lar corner sections. As with the flat nets, a section of webbing is cut out of the
bottom belly creating "the overhang. This trawl was used on medium sized vessels for
both groundfish and bottom fish. The wings of this trawl were tapered at the "door
end" to accomodate" the attachment of doors. The doors were attached directly to the
wing ends. The wings of this trawl show what came to be known as "wing trawls" or
trawls in which the wings we.re longer that the depth of the bellys. In these trawls
wings were just lengthened when a larger trawl were desired.
Clark Cotton Trawls
The "Clark Cotton Trawls" was a much larger trawl built similar to the
Nantucket trawl (1930-1940). The trawl consists of four wings, a top and bottom
belly, a graquated extension, and four triangular corner sections. The wings are
tapered to facilitate the height of the doors. As with the Nantucket Trawl, the
doors were connected directly to the wing ends. The bottom belly is cut out~to~
the edge of each wing, again creating:: the overhang ahead of the sweep. This trawl
also utilizes large mesh size in the wings and belly to reduce resistence. The wings
are also very long in relation to the depth of the belly sections.
Long Island Balloon Trawls
The Long Island Balloon ,Trawl is a trawl with distinct design change from the
earlier flat and flounder drags. In this trawl a "wedge" section is place below
a rectangular wing. This wedge section greatly increases the height of the wing
and correspondlingly the wing end height. Overhang is created by cutting avay a
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small section of the bottom belly. Thus this trawl is able to capture high swimming
off bottom species of fish such as fluke and scup. As with the previous trawls, four
triangular sections are used on the top and bottom bellys to reduce stress on the
wings. This trawl is also one of the first to be a four gore trawl in the bellys and
a two gore trawl in the wings. This type of trawl is still used in southern fisheries
for shrimp.
Cruz Cotton Trawls
The Cruz Cotton Trawl (1930-1935) could be considered a transitional trawl. In
this design the bottom belly is no longer cut away in order a create the overhang.
The reation of the overhang ahead of the sweep is created by the addition of a
rectangular square section. The bellys are also graduated, that is they contain
differing mesh sizes. Cruz Cotton trawls resemble the earlier trawls in so much as
they still have the four triangular sections to reduce stress between the square and
bottom belly. Wings are slightly tapered toward the door end. Simular to the
balloon trawls, the gore of the cruz cottom trawl st~ps at the bellys. This trawl
was used for groundfish such as yellowtail flounder, cod, and haddock.
Cruz Manila Trawls
The Cruz Manila Trawls (1940-1945) contains several design changes. This trawl
contains the top and bottom wings, a rectangular square, and top and bottom graduated
bellys. The wings consist of several sections which are sewn together before being
attached to the wings as earlier trawls but runs the entire length of the trawl.
The design concept is very much like the trawls used today, although this type of
trawl is no longer in use.
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Yankee Trawls
"Yankee Trawls" of European design replaced the Icelandic trawls in New England
in the early 1940's. Severe difficulties in obtaining pre-tapered net sections arid
the nets themselves caused the popularity of the Icelandic Trawls to fade. All net
sections for the Yankee Trawls were originally imported from Europe, Today pre
cut sections and complete trawls are available from domestic twine lofts. The"
Yankee~ series trawls are all two panel and still can be found aboard trawlers in
many New England ports.
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Conclusion
Trawling for both bottom and off bottom fish has developed several New England
fisheries. The development of trawls and supporting deck equipment continues as
vessel requirements for certain fisheries change. The design of the trawls them
selves however have remained fairly consistent. Advances in net design have been
slow and many fishermen resist attempts to modify present fishing methods or practices.
The best example of this slowness to accept improved fishing procedures lies with
the Vigneron Dahl Trawl. This trawl was developed in France for use in bottom
fisheries about 1920. The "V.D." trawl utilized "bridles" of rope and wire between
the trawl and the trawl doors. The use of ground cables and_legs greatly increased
the efficiency of the trawl. It was not accepted and fished by Stonington Connecticut
fishermen however, until 1958 or about four decades later. European designs and
trawling equipment will in the forseeable furure, influence New England fisheries,
as the art and practice of trawling has been developing there for centuries. I'm
also certain the improved trawl designs will be developed from within the New
England Industry. The collection of early trawl net designs clearly proves the
ability to experiment with trawls and to adapt trawls for the unique conditions of
the New England trawl fisheries.
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BEAM TRAWL NET PLAN (1900)
Bottom Panel... ------.-iillllillll-..... -'~ A.U.'"· .... '.~" •.•. "" "'t:-...TOD Panel .
4" Mesh 4" }lesh M"") ~
4" Mesh4" Mesh
4" Mesh 4" Mesh
60
25 d 60
60
25 d
60
TWO GORE FLOUNDER DRAG NET PLAN (1910)
'T nn _uP_..QnLJ:p~l "Rn""""I"'\'fn "P~~1 ~--\'"
~ ~4" Mesh
4" Mesh
\ 84 ,
4" Mesh 80 d 4" Mesh
r:25 /
5~ 50 d I 3" Mesh I 50 d .
3" Mesh
65
10
FLAT NET NET PLAN (1920)
Top Panel
Bars
A 26 d
A
54
26 26 d 26
Bottom PaTlPl
1212 1212
80 dl 4" Mesho d4" Mesh lr') ~
4" Mesh4" Mesh
3" Mesh3" Mesh
..... IIU"..'~.... i:t. Uf ' J > -" __
30
20 d
30
30 20 d
LONG ISLAND BALLOON TRAWL NET PLAN
Bottom PanelTop Panel
38 d 38 d 4" Mesh4" Mesh ~ ~
4" Mesh
80 u 4" Mesh
60 /
I I 3" Mesh60 100 d
, 2.Q 50
I SOlOOld 2.5" Mesh
~ J
48 d
64
3" Mesh
2.5" Mesh
48
64
CLARK COTTON TRAWL NET PLAN (1930)
Top Panel I Bottom Panel
\ 35 d I
\ - -,-+" /
6" Mesh6" Mesh
"~
6" MeshI6" Mesh
I 5" Mesh5" Mesh
30
/I~ , 30
50 d 4" Mesh 50 d I 4" Mesh
.42 42 25 d
63 ··d
166 25 d 131 m
Too Panel
37
\68
5;----{53
36,A,,A,
65.5
Bottom Panel
I 37
68 4" MeshI
53
53 , 4" Mesh 65.5
4" Mesh 00 I. ~ / A ~I 1 I
54 'A' L.J U/ 4" Mesh 1 \ - . - I 4" Mesh
3" Mesh 3" Mesh
3" Mesh84 d3" Mesh
54 I\
112 27 d 112
39
84 d
39
I
I
I
I
IlI
CRUZ MANILA TRAWL NET PLAN
Bottom PanelTop
65
17
Panel
176 154 154
~ 80 d 80
6" Mesh65
17
6" Mesh
6" Mesh
29 d 6" Mesh
5" Mesh
4" Mesh
3" Mesh
,3" Mesh
67 d
24.5
I I 30 d \
I \
I
6" Mesh67 d
24.5
24.5-24.5
I 30 d I 6" Mesh
29 d I 6" Mesh
5" Mesh
4" Mesh
Mesh
I 80ld 3" Mesh
NANTUCKET TRAWL NET PLAN (1940)
Bottom PanelTr\n .. P!:ln.aJ
18 18
110 100 dl 4" Mesh
32 32
32 32
55 d I ... A
55 d I 4" Mesh 0 ~
4" Mesh4" Mesh Q() -
\ C 20 d /
55 d 4" Mesh 4
50
1955 d Mesh
40
5" Mesh
YANKEE 36 TRAWL NET PLAN (1945)
Tf"'\1"\ P~no1
sq 50 d
50
5" Mesh
5" Mesh
4.5" Mesh
Bottom Panel
5" Mesh
~
N
Mesh
5" Mesh
4.5" Mesh
50
50 d
50
5"