Improvements in Otter Trawls.
Year: 1895

page_text: Date of Application, 19th Oct., 1895
Complete Specification Left, 20th July, 1896-Accepted, 10th Oct.. 1896
Improvements in Otter Trawls.
I, WILLIAM JACKSON of 5 Shelgate Road Clapham Junction, Medical Student,
do declare the nature of my invention for the Iimprovement' in Otter Trawls to
bo as follows:-
--
This invention has reference to maintaining a permanant shear in otter trawls.
The otter trawl heads at present in use, have three or more attachments namely―
what is known as the headline, what is known as the ground-rope, and what is
known as the warp or bridle, and the like.
The warp or bridle is fastened to the otter head by. chains or iron bars, in such
a manner as to give the otter head the desired shear.
The headline and ground-rope are attached to some part of the after end of the
otter head, the headline usually near the top, and the ground-rope usually near the
bottom
Now by reason of the headline and ground-rope being fastened to the back edge
of the otter head, the shear given by the arrangement of the chains or bars is much
modified, or entirely destroyed, according to the strain which is exerted by the
headline, and ground-rope respectively, this strain depending on the weight and
size of the net-and frequently altering in amount according to the pace at which
the vessel is going, the ground over which the net is towed, and the quantity of
fish or other things in the net, and a variety of other causes.
In practice as soon as the shear of the otter has opened the mouth of the net a
little way, the strain of the ground-rope entirely destroys the shear of the otter,
and the otter has no further power of distending the net.
In my otter all attachments emanate from one point, so that whatever shear is
originally given to the otter, with regard to any one attachment, it will retain that
shear with regard to that attachment without modification no matter what strain
may be on oi fiom any other attachment.
The arrangement of my otter is as follows-
A bar or shear pole is fixed through the otter, at any point of its surface at any
angle preferably at, or near the centre.
き
The bar or shearpole may be of any length, and may protrude either from both
the front and back surfaces of the otter, or from the front surface only, or from
the back surface only-the warp or biidle, the ground-rope, the headline, and any
other attachments, are all fastened either directly or indirectly to oue and the same
point, but this point may be at any part of the otter.
Instead of the bar or sheai pole an equivalent arrangement of ropes, chains, or
bars may be substituted.
The warp or bridle, the headline the ground-rope and any other attachments,
may be fastened either directly to the point, (that is to say as close to the point
as practicable and shackled or fastened either close up to the front or close up to
the back surface of the otter), or indirectly to the point, by being attached to any
part of the bar o shearpole, either on the part protruding from the front surface of
the otter, or from the part protruding from the back surface of the otter, or they
may all or any of them be attached indirectly to the point by means of an
arrangement of ropes, or bars, or chains, or the hike, when the resultant of such
arrangement would be equivalent to a rope leading directly from the point or
nearly so.
t

page_text: The bar or shearpole may be fixed in its position by means of stays, chains or
other supports.
Swivel shackles are used for connecting the attachments to the otter.
The bar may be fixed at such an angle as to give the otter a shear upwards, or
downwards in addition to the lateral shear.
An additional otter, or otters may be used in a horizontal position with bar or
shea pole and attachments arranged in a similar manner. The otter having a
towing warp attached, and fastened to the headline or ground-rope or both either
directly or by means of short bridles.
Instead of the horizontal otter, a herring bole or other float may be
substituted.
19th October 1895
PPS Trawls.
1, WILLIAM JACKSON of 5 Shelgate Road Clapham Junction Medical Student,
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to the maintaining a constant shear in otter trawls.
The otter trawl heads at present in use bave three or more attachments, namely
what are known as, the headline, the ground rope, the warp or bridle, and
the like.
The warp or bridle is fastened to the otter head by chains or bars in such a
manner as to give the otter head the desued shear.
The headline and ground rope are attached to some part of the after end of
the otter head, the headline usually near the top and the ground rope near the
bottom.
'
By reason of the headline & ground rope being fastned to the after edge of the
otter head, the shear given by the aangement of the bats or chains is much
modified, or entirely destroyed, according to the strain which is exerted by the
headline and ground rope respectively, this strain depending on, the weight and size
of the ground rope, the weight and size of the net and constantly altering in
amount, according to the pace at which the vessel is going, the ground over which
the net 18 towed, and the quantity of fish or other things in the net, and a variety
of other causes.
In practice as soon as the shear of the otter has opened the mouth of the net a
little way, the strain of the ground rope destroys the shear of the otter and the
otter has no further power of disteuding the net.
In my otter all attachments emanate through one straight line so that whatever
shear is originally given to the otter, with regard to any one attachment it will
retain that shear with regard to that attachment without modification no matter
what strain may be on, or fiom, any other attachment.
The arrangement of my otter is as follows
A bar or shearpole is fixed through the otter at any point of its surface,
preferably at or near the center, and at any angle.
The bar o shearpole may be of any length, and may protrude either from the
back or front surface of the otter or from both and may be made of steel, non,
wood on the like.
The warp or bundle, the groundrope, the headline and any other attachments are
all fastened either directly or indirectly to one and the same point.
This point may be at any part of the otter.

page_text: Instead of the bar or shearpole an arrangement of ropes, chains or bars may be
Bubstituted either at the front or the back of the otter or both, and in this case all
attachments will not emanate through one point, but the resultant of the com-
bination would emanate from one point and would be practically and mechanically
equivalent to a bar 1ope' o1 chain leading from such a point at such a resultant
angle.
The warp or bridle the headline, the ground rope and any other attachments,
may be fastened either directly to the point (that is to say as close to the point as
practicable and shackled or fastened either close up to the front or close up to the
back surface of the otter) or indirectly to the point by being attached to any part
of the bar or shearpole either on the part protruding from the front surface of the
otter, or from the part protruding from the back surface of the otter, or they may
be all or any of them attached indirectly to the point by means of an arrangement
of ropes or bars, or chains or the like when the resultant of such arrangement
would be equivalent to a rope leading directly from the point or nearly so.
In figs. W is the warp or bridle-H is the headline-G the groundrope-B the
bar or shearpole-P the point of attachment.
Fig. 1. is an horizontal section of otter showing attachment of headline close
to Pat foreside of otter.
Fig. 2 is an horizontal section of otter showing attachment of headline and
ground rope to prolongation of bar at the back of the otter.
Fig. 3. is front view of otter.
Fig. 4 is vertical elevation showing attachment of beadline and ground rope
close to P on the back side of otter.
The bar or shearpole may be fixed in its position by means of stays chains or
other supports.
Swivel shackles are used for connecting the attachments to the otter.
The bar may be fixed at such an angle as to give the otter a shear upwards or
downwards in addition to the lateral shear.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim 18
A novel arraingment of bats, chains, or shearpole on or attached to otters.
1
DOLL 1000
WILLIAM JACKSON.