Improvements in and relating to Trawl Net Fishing, and Appliances therefor.
Year: 1894

page_text: Date of Application, 24th-Oct.,-1894
Complete Specification Left, 24th Aug., 1895-Accepted, 19th Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in and relating to Trawl Net Fishing, and Appliances
therefor.
I, WILLIAM ADAM of Chemical Works, Burghead, Elginshire, Chemical
Manufacturer, do hereby declare the nature of my invention to be as follows :—
This invention has reference to improvements in trawl net fishing for herrings
and other fish found in quantity at or near the surface of the water in such places
as rivers, lochs, or at sea, and comprises improvements in the construction and use
of the trawl net and in a receiving tank or vessel for the reception of the fish
enclosed within the net, and has for its object the catching of fish in large quantities
and in a continuous manner.
The trawl net may be varied somewhat in details of construction but would
preferably according to one modification be formed of a trough shape open at top
which would be maintained at or near the surface of the water, contracted to a
small size at back. end, and widening towards the front end both vertically and
horizontally so as to assume a pyramidical shape in the water, and thus present a
wide opening for the entrance of the fish, tapering to a small size at the discharge
end of the net where a short parallel passage would be formed for the purpose of
guiding the fish into the receiving tank or vessel as will be described. The net
would be formed of twine, rope, metal, wire or any other suitable material and the
two side top edges would be secured to a strong hawser, to which might be
attached a series of bladders or other buoyant appliances or material to hold up
the net, and assist in maintaining the upper edges at a level with the surface of the
water.
These two hawsers or the top edges of the net might also be connected together
by ropes or cords of a graduated length to prevent them spreading out too widely,
and also assist in strengthening the whole net, while the smaller contracted end
would preferably be formed of much stronger material than the main body of the
net. The lower front edge of the net may be weighted to keep it down in the
water and prevent the mouth from contracting vertically.
By another modification the two upper side edges of the net instead of being
connected together by cords or ropes may be connected by netting so as to form a
net enclosed on all sides, but nets of circular or other form may be used.
The net formed as described would be towed along the surface of the water
preferably by two small steamers or tug boats attached to it by a continuation of
the hawsers carrying the net, these steamers being sailed at the distance apart
requisite to maintain the mouth of the net at its maximum width, and guy ropes
would be carried from the lower front corners of the net to the hawser in advance
of the net, and the receiving tank or vessel being secured to the other end of the
hawsers at the small end of the net, acting as a drag would keep the hawsers
stretched at the surface of the water.
Other vessels than steamers may be used for towing the net, such as sailing
vessels, or vessels propelled by motive power other than steam.
These nets as described have no beams but such may be provided such as a
buoyant beam, or one supported by buoyant means, for the top of the net mouth,
and a weighted beam for the bottom, and either or both of these may be used. In
cases where a top stretching beam is used the net could be towed by one vessel
nstead of two or more.
A portion of the small end of the net may be lined or covered with strong

page_text: canvas or similar material in order to induce a strong current of water through the
discharge passage.
The receiving tank or vessel into which the fish would be discharged from the
small end of the net would preferably be a small steamer capable of proceeding to
a port of discharge when loaded with fish, but it may be a vessel fitted with
any kind of motive power or one without motivo power, but capable of being
towed.
When a steamer is used the engine and boiler as well as crew accommodation
would preferably be situated towards the stern end, and in front of these the hold.
An internal opening or passage preferably square or rectangular and extending
below the water line and some distance into the vessel would be formed at the bow
end, and hinged or other doors may be provided for closing this opening when the
vessel was detached from the net. Within this passage a grating would be placed
sloping up at an angle to the level of the deck or a little above it and below this
grating the passage might be open to the water and beyond the grating water
ways would be led to the sides of the vessel for the escape through ports,
openings or perforations, of the water driven in along with the fish. The small
end of the net which may be kept distended by a metal frame would be secured by
any ordinary fastening means within the outer end of the passage in the bow of the
vessel, suitable means of access being provided.
When in use the action of the whole would be as follows
The towing vessel or vessels moving at the desired speed would keep the hawsers
and net stretched on or near the surface of the water and all fish enclosed by the
mouth of the net would gradually be carried back to the narrow neck at back end
of trawl net. They would then enter the passage in the bow of the receiving
vessel and be driven up the inclined grating by the force of the water entering
along with them, and be thrown up on deck from whence they would fall down or
be thrown into the hold by those in charge, the water running off from the sides of
the vessel.
Other forms of vessels may be used, the main essential feature being the forming
of the internal passage fitted with the inclined grating as described, or an equivalent
passage way cr duct fitted with angle grating might be projected outwards from
the vessel for the same purpose.
Dated the 23rd October 1894.
W. R. M. THOMSON & Co.,
96 Buchanan Street, Glasgow, Agents.
Improvements in and relating to Trawl Net Fishing, and Appliances
therefor.
I, WILLIAM ADAM, of Chemical Works, Burghead Elginshire, Chemical
Manufacturer, 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 reference being made to the accompanying
drawings
This invention has reference to improvements in trawl net fishing for herrings
and other fish found in quantity at or near the surface of the water in such places
as rivers, lochs, or at sea, and comprises improvements in the construction and use
of trawl net and in a receiving tank or vessel for the reception of the fish enclosed
within the net, and has for its object the catching of fish in large quantities and in
a continuous manner while enabling small or immature fish to escape or be returned
to the sea; and in order that my said invention may be properly understood,
I have hereunto appended two sheets of explanatory drawings in which
Figure 1 on Sheet 1 is a side view of the whole appliance as being operated, and

page_text: Figure 2 is a corresponding plan view while Figure 3 is a perspective view to an
enlarged scale of the back or contracted end of the trawl net.
Figure 4 on Sheet 2 is a side view partly in section of the fish receiving vessel
and Figure 5 a sectional plan of the bow end showing the construction ; while
Figure 6 is a view of the bow of a fish receiving vessel fitted with a modified
arrangement which may be employed for receiving the small end of the net.
The trawl-net A may be varied somewhat in details of construction, but is
preferably, according to one modification, as shown in Figures 1, 2 and 3, formed
of a trough shape, open at the top which is to be maintained at or near the surface
of the water, contracted to a small size at back end A' and widening towards the
front-end A both vertically and horizontally so as to assume a pyramidical shape
in the water and thus present a wide opening for the entrance of the fish tapering
to a small size at the discharge end A¹ of the net where a short parallel passage is
formed for the purpose of guiding the fish into the receiving tank or vessel V to
be described. The net A may be formed of twine, rope, metal, wire, links, or any
other suitable material and the two side top edges are secured each to a strong
hawser B to which are attached a series of bladders B¹ or other buoyant appliances,
or material to hold up the net A and assist in maintaining the upper edges at a
level with the surface of the water W. These two hawsers B or the top edges of
the net are connected together by ropes or cords ↳ Figures 2 and 3 of a graduated
length to prevent the net A spreading out too widely, and also assist in
strengthening it while the smaller contracted end is preferably formed of much
stronger material than the main body of the net. The lower front edge of the net
may be weighted to keep it down in the water and prevent the mouth from
contracting vertically.
The two upper side edges of the net instead of being connected together by
cords or ropes b, may be connected by netting so as to form a uet enclosed on all
sides, but nets of circular or other form may also be used.
The net formed as described is towed along the surface of the water preferably
by two small steamers or tug boats T attached to it by the hawsers B carrying the
net, these steamers T being sailed at the distance apart requisite to maintain the
mouth of the net at its maximum width. Guy ropes b' are carried from the lower
front corners of the net A to the hawser B in advance of the net, and other guy
ropes 6* may be carried diagonally between the hawsers B and the opposite sides of
the net A. The receiving tank or vessel V is secured to the other end of the
hawsers B or to the frame F at the small end of the net A and acting as a drag
keeps the hawsers stretched at or near the surface of the water. Other vessels
than steamers may be used for towing the net, such as sailing vessels, or vessels
propelled by motive power other than steam.
The trawl-net as described, has no beam but beams may be provided such as a
buoyant beam, or one supported by buoyant means, for the top of the net mouth,
and a weighted beam for the bottom, and either or both of these may be used. In
cases where a top stretching beam is used, the net could be towed by one vessel
instead of two or more. A portion of the small end of the net may be lined or
covered with strong canvas or similar material in order to induce a strong current
of water through the discharge passage as indicated in Figure 3 at A*.
The receiving tank or vessel into which the fish would be discharged from the
small end of the net is preferably a small steamer capable of proceeding to a port
of discharge when loaded with fish; but it may be a vessel fitted with any kind of
motive power or one without motive power, but capable of being towed. When a
steamer is used, the engine and boiler as well as crew accommodation would
preferably be situated towards the stern end, and in front of these the hold. An
internal opening or passage preferably square or rectangular and extending below
the water line and some distance into the vessel would be formed at the bow end,
and hinged or other doors may be provided for closing this opening when the
vessel was detached from the net. Within this passage, a grating would be placed
sloping up at an angle to the level of the deck, or a little above it and below this

page_text: grating, the passage might be open to the water and beyond the grating water
ways would be led to the sides of the vessel for the escape, through ports, openings,
or perforations, of the water driven in along with the fish. The small end of the
net which may be kept distended by a metal frame, is secured by any ordinary
fastening means within the outer end of the passage in the bow of the vessel,
suitable means of access being provided. Preferably the fish receiving vessel V.
is constructed and fitted as illustrated in Figures 4 and 5 on Sheet 2 of the
drawings. This vessel V is formed with an opening C at the bow, this opening
being fitted with doors C¹ C¹ operated by chains or cords c c² for the purpose of
closing or opening them as required. The small end of the net A is drawn within
the opening C by means of cords or chains fattached to the frame F and operated
and secured by the windlass G or other suitable means.
Within the opening C
is placed the perforated inclined plate E between the bulkheads V₁ and to the
inner end of the inclined plate E is jointed the perforated plate E' fitted with side
plates E³. The end of this jointed plate E' projects through an opening in a sliding
door H sliding in guides on the angled bulkhead Vs. This door as it is raised
and lowered by rack mechanism H¹ raises and lowers the free end of the plate E¹
which rests on antifriction rollers on the edges of the opening in door. A
waterway I is formed under the inclined plate E to receive the water passing down
through it which is allowed to escape through openings I¹ in the bulkheads V¹
into the angled waterways J and from them to the sea by means of perforations
or openings in the vessels sides at J'. The compartments formed by the longi-
tudinal bulkheads V' and the angled bulkheads V³ may be utilized as
compartments to give buoyancy to the fore part of the vessel, or by employing
water ballast therein and the necessary pumping apparatus they may be employed
as a means of maintaining the fore part of the vessel at a fixed level in relation
to the water. The fish carried through the small end of the net A by the force
of the current of water as the vessel was towed along would enter through the
opening C, pass up over the plates E and E' and fall over the open end of the
plate E into the well K whence they would he carried up by the buckets, formed
of wire netting or perforated metal, of the elevator L driven by the donkey
engine L. From the buckets of the elevator L they would be discharged into
the hold M by means of the shoot N. The bulk of the water entering the opening
along with the fish escapes by the waterways I and J and openings K¹ covered
by the gratings or wire netting would be formed in the sides of the well K to
prevent the water therein rising above the sea level. When in use, the action of
the whole is as follows:-
air
The towing vessel or vessels moving at the desired speed would keep the hawsers
and nets stretched on or near the surface of the water and all the fish enclosed by
the mouth of the net, would gradually be carried back to the narrow neck at the
back end of trawl net. They would then enter the passage in the bow of the
receiving vessel and be driven up the inclined grating by the force of the water
entering along with them, and be thrown up on deck or preferably into the well
from whence they would fall down or be thrown into the hold by those in charge
or carried up from the well by the elevator and discharged into the hold-the
water running off from the sides of the vessel through the openings provided.
Other forms of vessels may be used, the main essential feature being the forming
of the internal passage fitted with the inclined grating as described or in an
equivalent a passage way or duct fitted with angle grating may be projected
outwards from the vessel for the same purpose as indicated at O by Figure 6.
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 :-
1. The means or appliances and the mode of operating same for catching fish in
a continuous manner all substantially as herein described and illustrated by the
accompanying drawings.

page_text: 2. For catching fish in a continuous manner the use of a trawl-net and a fish
receiving vessel with inclined passage and waterways-constructed and fitted all
substantially as herein described and illustrated by the accompanying drawings.
3. For catching fish in a continuous manuer the construction and use of a trawl
net all substantially as herein described and illustrated by the accompanying
drawings.
4. For catching fish in a continuous manner, the fitting of a fish receiving vessel
with inclined passage with perforated bottom and water ways all substantially as
and for the purposes herein described and illustrated by the accompanying
drawings.
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100%
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.