TRAWLING NETS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by William Blacklock Wilson at the
Office of the Commissioners of Patents on the 12th February 1883.
WILLIAM BLACKLOCK WILSON, of Aberdeen, North Britain
IN TRAWLING NETS
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:
"IMPROVEMENTS
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My invention relates to an improved appliance for effectually spreading the net,
and it is of such dimensions that an 80 feet stretch can be easily accomplished
and the trawling take place on any ground and with less difficulty than with the
trawling nets now in use. The appliance consists of two sides made of plate iron
and accessories as hereinafter described.
The sides are so made that they can be taken inboard in any weather with no
danger of damaging the ship's side or of jeopardizing the lives of those working
the net. When the net is cast into the sea, by the vessel being set in motion it
will immediately spread to whatever length the stays will allow, but should it
happen that owing to the unevenness of the ground or from any circumstances
whatever the not does not get properly settled on the bottom, by giving to the
vessel a little more speed, it will properly adjust itself and there will be no
necessity for taking it inboard again. The construction of the net-work is such
that fish when once in cannot get out again, even supposing the net is allowed to
lay still, thus when any anchor or wreck has fouled it, by dropping and buoying
the hauling lines and getting hold of the cod end which is fixed for the purpose,
the net can be pulled back and saved, while the fish cannot escape, which is the
case with nets used at present.
The whole balancing of the net is such that there will be little friction to
contend with and it can be pulled over the ground at a quicker pace without either
the danger of trawling over the top of the fish or lifting the net from the ground,
the advantages being that the fish can be caught more expeditiously, the cost of
keeping up material will not be so great, there will not be so much risk in working
the net, and that it does away with the large, heavy beam now used for keeping the
sides of the net apart. The side of the net stretcher is of such dimensions as will
suit the size fixed upon to be spread; for an 80 feet spread it is about 5 feet high
at the foremost end, the top being about 4 feet in length and then descending
gradually towards the outer end, the base being about 8 feet in length. The sides
may be made of plates sliding telescopically up and down, so as to increase or

page_text: decrease the height as required. The top is provided with an air vessel fitted for
the purpose of keeping the side upright; no matter how it is thrown into the sea,
it will always stand upright at the bottom and be in readiness for spreading itself.
The air vessel is made of iron and attached to the top, and extends along the same.
It is of such capacity that the side will not weigh more than one-third the weight
in the water as compared with what it weighs in the air.
Fixed to the side are two wheels, on either side of the iron plates, the outer one
being of a smaller diameter than the inner one, the axis of said wheels being on the
slant, so that when the net settles on the bottom, the tendency of the wheels when
put in motion is to carry the sides outwards. The bottom of the side is fitted with
flat plates or runners, so that in case of soft ground, the sides will not sink into it,
or cause undue friction. The two sides are alike in every respect, and the ropes
connecting them with the vessel are attached towards the centre. There are stays
on the fore and after part, so that when the net is at full stretch, the strain does
not come on either the head or foot ropes. The head rope is fitted with small iron
buoys, placed so far apart, that when the net is in motion it has the appearance of
an arch. There are two foot ropes, to which are attached iron plates, for the
purpose of effectually sinking them in the water, while at the same time, they
prevent these ropes becoming embedded in the mud. The object of the two foot
ropes is that should the first one by the increased rate of speed pass over the top of
the fish, the second one is sure to catch them and lead them into the net. The net
is constructed like a V in the centre, with convenient apertures for the fish to enter,
the entry being kept apart by small pieces of wood placed at suitable distances.
This entry is in the middle of the net, so that should the fish go to either the top
or bottom they cannot get out, even in the case of the net being still. Round the
_belly of the net is a rope with both ends fast on the ship, and so fastened that the
weight of fish or any other weight in the net is taken off the sides, so as to prevent
the danger of the sides closing.