Improvements in and relating to Trawl-beams and Trawl-heads used in Net Fishing.
Year: 1892

page_text: Date of Application, 6th May, 1892
Complete Specification Left, 4th Feb., 1893-Accepted, 18th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in and relating to Trawl-beams and Trawl-heads used
in Net Fishing.
I, WILLIAM GUNN, of Granton Harbour, near Edinburgh, in the County of
Midlothian, Agent, do hereby declare the nature of my invention to be as
follows:-
From the commencement of trawl net fishing, wooden beams have been used; as
time progressed larger vessels have been employed, and at the present time
powerful steam vessels are used for the purpose of trawl net fishing, necessitating
longer and stronger beams; the disadvantages of which are many, more
particularly the difficulty of getting a beam in one length, hence splicing has to
be resorted to, the greatest objection however being the great displacement of the
beam which retards the progress of the vessel trawling.
The ordinary trawl-beams at present in use are from about 50 to 60 feet long,
and about 10 or 12. inches in diameter. They are towed by wire or hemp bridle
ropes from each end of the beam. Each bridle rope is about 20 fathom long,
terminating or meeting together at the corner of a triangle, and attached to the
tow-rope by links or shackles. It is a well known fact that when the beam meets
with obstructions at the bottom of the sea, the beam must break at a less strain
than the bridles and tow-rope can bear, failing which the other gear will give way,
and the beam, net, and other gear will be lost.
My improvements consist first in constructing a trawl beam of steel, iron, or
other strong metal of angle, I, rail, or other section, either solid or tubular, but
preferably in two longitudinal parallel parts of inverted T section rivetted or
bolted together parallelly along the horizontal flange webs, and made either
continuous or in two or more lengths, suitably connected together by butt or
other joints and extending preferably to about 50 feet. The centre part of the
beam, preferably for about 12 feet, would be made up with wooden segments
fitting into or around the metal part to make up a round section at this part
of the beam, preferably about 10 inches diameter, secured. together by ring
hoops and nails or bolts, or other equivalent disconnecting fastenings, so as to
automatically get disconnected should the beam get entangled. The breaking
strain would thus bear upon the weakest part, namely, the central wood part of
beam which will break up or give way when the beam sticks or gets entangled at
the bottom of the sea and a heavy pressure or strain comes on, and thus liberate
the beam without losing the nets or gear. The outer ends of the iron beam are
made up with wood to form a square head for being fitted to the eye of the trawl-
head which is generally 6 inches square, for the attachment of the trawl-head on
the beam. The webs of the iron or steel plates would or may be filled up with
wood, so as to prevent them chafing the ship's sides when the beam is in action.
The weight of the iron part of the beam will give it more sinking power than
wood, and admit of lighter trawl-heads being used, while the smaller section of
metal will give it less resistance and displacement than the ordinary wooden
trawl beams.
The trawl-beads heretofore used were made of bars of flat or square section
iron rivetted together to form an oblong shape, and having an iron buckle or eye
on the top for attaching the trawl-head to the trawl-beam. By my improvements
the trawl-head is formed of sheet-iron or steel in one piece, stamped, cut, or
otherwise formed to the shape or configuration desired, and preferably of from
about th to 1 inch in sectional thickness according to the strength and size of

page_text: trawl-head desired, and a sectional part or parts may be cut out of the centre of
the plate to lessen the weight if requisite. A series of transverse axles or rods
are fitted at the bottom part of the plate or trawl-head, preferably extending the
greater part of its length, and on these wheels or rollers are mounted and secured,
preferably one on each end of each axle, and by this means the trawl-head will
travel on the ground much easier and with less friction than the sliding shoe plates
heretofore used, although these may be employed if desired by being secured to
the plate frame by knees or angle irons and bolts or rivets.
Dated the 5th Me.. 1000
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to Trawl-beams and Trawl-heads used
in Net Fishing.
I WILLIAM GUNN of Granton Harbour near Edinburgh in the County of
Midlothian, Agent do hereby declare the nature of my invention, and in what
manner the same is to be performed to be particularly described, and ascertained
in and by the following statement in writing that is to say:-
From the commencement of trawl net fishing, wooden beams have been used, as
time progressed, larger vessels have been employed, and at the present time
powerful steam vessels are used for the purpose of trawl net fishing necessitating
longer and stronger beams the disadvantages of which are many, more particularly
the difficulty of getting a beam in one length, hence splicing has to be resorted to,
the greatest objection however being the great displacement of the beam, which
retards the progress of the vessel trawling.
The ordinary trawl-beams at present in use, are from about 50 to 60 feet long,
and about 10 or 12 inches in diameter. They are towed by wire or hemp bridle
ropes, from each end of the beam. Each bridle rope is about 20 fathoms long,
terminating or meeting together at the corner of a triangle, and attached to the
tow-rope by links or shackles. It is a well known fact that when the beam meets
with obstructions at the bottom of the sea, the beam must break at less strain
than the bridles and tow-rope can bear, failing which the other gear will give way,
and the beam, net and other gear will be lost.
And in order that my said invention, and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended an explanatory sheet of drawings in which the same reference letters,
are used to indicate equivalent parts in all the figures where shown,
Figure is a longitudual elevation of the central part of a trawl bean as
constructed of I or girder section iron filled up with wood on each side as
constructed in accordance with one arrangement of my improvements.
Figure 2 is a plan view corresponding to Figure 1 showing the joint through
the centre part.
elliptical
Figure 3 is a transverse section of the iron part of beam, and
Figure 4 is a transverse section as taken on the line 1-1 Figure 1.
Figure 5 is a transverse section showing the beam as formed of an
shape and the metal part as formed of double T iron rivetted together.
Figures 6 and 7 are a longitudual elevation and transverse section on the
line 6-6 showing the metal part of the trawl beam as formed of four angle irons
rivetted together.
Figure 8 is a transverse section showing the metal part of beam as formed of
star section.
Figures 9 and 10 are a longitudual elevation, and transverse section on the
line 9-9 showing the trawl beam as formed of a series of metal tubes a grouped
and bound together by metal hoops, and

page_text: Figure 11 is a transverse section showing the metal part of beam as formed of
rail section.
Figures 12 to 18 show elevations to a small scale of modified forms of trawl
heads as constructed in accordance with my improvements.
Referring to these drawings:-
My improvements consist first, in constructing a trawl beam of steel, iron or other
strong metal of angle I, rail or other section either solid or tubular as shown in
Figures to 11 of these drawings, but preferably in two longitudinal parallel
parts A, A of inverted T section rivetted or bolted together parallelly along the
centre horizontal flange webs, and made either continuous, or in two or more
lengths suitably connected together by butt or other joints as shown in Figures 1, 2, 6,
and 9, and extending preferably to about 50 feet. The centre part of the beam,
preferably for about 12 feet would be made up with wooden segments B. B. fitting
into or round the open metal part A to make up a round or elliptical section at
this part of the beam, preferably about 10 inches diameter, secured together by ring
hoops at A and nails, or bolts, or other equivalent disconnecting fastenings, so as
to automatically get disconnected should the beam get entangled. In Figures 1 to 4
the beam as shown as formed of I or girder section with a part of the main web A
cut away at A, and filled up with wood B on each side of the central web, and
joined to the wood by outer fish plates A³ and bolts.
The breaking strain would thus bear upon the weakest part, namely, the central
wood part, at the joint A² of beam, which will break up or give way when the
beam sticks or gets entangled at the bottom of the sea, and a heavy pressure or
strain comes on, and thus liberate the beam without losing the net or gear. The
outer ends of the iron beam A are made up with wood to form a square head for
being fitted to the eye C of the trawl-heads C which are generally six inches
square for the attachment of the trawl-head on the beam. The webs of the iron
or steel plates A would or may be filled up with wood B so as to prevent them
chafing the ship's sides when the beam is in action.
The weight of the iron part A of the beam will give it more sinking power than
wood, and admit of lighter trawl-heads being used, while the smaller section of
metal will give it equal strength and less resistance and displacement than the
ordinary wooden trawl beams.
The trawl-heads heretofore used were made of bars of flat or square section
iron rivetted together to form an oblong shape somewhat similar to the outline of
Figure 12 and having an iron socket or eye C² on the top for attaching the trawl
head C to the trawl beam A. By my improvements the side of the trawl head is
formed of sheet iron or steel in one piece C stamped, cut, or otherwise formed to
the shape or configuration desired and have flanges of edge bars C¹ Figure 18
secured or rivetted on by angle irons C" the plate C being about th to 1 inch in
sectional thickness according to the strength and size of trawl head desired, and a
sectional part or parts may be cut out of the centre of the plate at C to lessen the
weight and allow the water to flow through when setting away the gear. A series
of transverse axles or rods are fitted between longitudual metal bands C
rivetted on each lower side of the plate C of the trawl head, preferably extending
the greater part of its length, and on these, wheels or rollers c' are mounted, and
secured, one on each axle, and by this means the trawl head C will travel on the
ground much easier, and with less friction than the sliding shoe plates C Figure 12
beretofore used, although these may be employed if desired by being secured to
the plate frame by knees or angle irons, and bolts or rivets, as shown at C₁ in
Figures 15 and 16, or the combination of the sliding plates C, and the wheels c, c'
may be employed as shown in Figure 17.
Figure 18 shows detached views of the upper outer band C¹ of the trawl head,
and sliding shoe C* for being secured to same.
These improvements may also be applied to the trawl heads heretofore in use
by inserting a plate and fixing it the flat inner surface on the frame of the head.

page_text: This invention is a great improvement on the present construction of trawl-
heads, it is lighter, stronger, easier to tow, and not so apt to become entangled by
obstructions at the bottom of the sea, as the open head in general use. This close
head prevents the fish escaping, as they now do through the open head before
coming to the connection of the net to the trawl-head.
Having now particularly described, and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
First. The construction of trawl-beams for fishing use of metal sections, jointed
at the centre or other part, and made up with wood or equivalent lapping material,
substantially as and for the purposes herein described in reference to, and by way
of illustration shown under several applications in Figures 1 to 11 of the accom-
panying drawings.
Second. The construction of trawl-beams for fishing use of metal sections with the
central part of beam formed of wood, substantially as and for the purposes herein
described in reference to and shown in Figures 1 to 11 of the accompanying
drawings.
Third. The construction of trawl heads for fishing use with the sides formed out
of one piece of sheet metal substantially as, and for the purposes herein described
in reference to and shown in the accompanying drawings.
Fourth. The construction of trawl heads for fishing use with a series of transverse
axles, and travelling wheels or rollers at their lower surface substantially as, and
for the purposes herein described in reference to and shown in the accompanying
drawings.
Dated the 3rd February 1893
W. R. M.. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.