Improvements on Otter Trawl Boards.
Year: 1898

page_text: Improvements on Otter Trawl Boards.
DAVID SHERHIT, Sheddocksley House, Aberdeen, Engineer, do hereby declare
the nature of this invention to be as follows:-
My invention relates chiefly to attachments connected with otter trawl boards,
so as to provide more efficient means of keeping the boards at the proper angle,
whilst they are being towed through the water, causing them to exert their
power in keeping the net always fully open, and at the same time, keeping the
boards in an upright position, whilst they are being pulled along with the net
attached.
A prominent part of my present invention is, that the attachments for fasten-
ing the head-line and ground-rope of the net are placed on the back of the boards
so as to cause the lines of force to pass through the boards to the towing line
attachments, which are placed on the front of the boards, the result is, that the
boards by this arrangement are kept at the proper angle, while being towed, and
therefore exert their power to keep the net at its fullest capacity. Provision
being made on the attachments so as to alter the angle of the boards at will
or if desired so as to give the necessary opening to the net without giving undue
strain to either trawl warp or net.
The boards to which these attachments are fixed may be the ordinary otter
trawl boards, but preferably they are rounded near from the after end on the
lower edge to the fore end, so as to have less resistance on the bottom of
the sea, and at the same time to allow the water to have its full power over the
boards whilst they are being towed. The lower edge of the boards, on the after
end are weighted and shod with cast iron, so as to keep them down only on the
after end, and thereby giving as little resistance as possible, whilst they are
being towed in an upright and angular condition, with the trawl net attached.
Dated this 12th day of November 1898.
Improvements in Otter Trawl Boards.
DAVID SHERRIT, Sheddocksley House, Aberdeen, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
My invention relates chiefly to attachments connected with otter trawl boards
so as to provide more efficient means of keeping the boards at the proper angle,
whilst they are being towed through the water, causing them to exert their
[Price 8d1

page_text: power in keeping the net always fully open, and at the same time keeping the
boards in an upright position, whilst they are being towed or pulled along with
the net attached.
A prominent part of my present invention is that the attachments for fasten-
ing the head-line and ground-rope of the net are placed on the back of the boards
so as to cause the lines of force to pass through the boards to the towing line
attachments, which are placed on the front of the boards, the result is that the
boards by this arrangement are kept at the proper angle while being towed, and
therefore exert their power to keep the net at its fullest capacity, provision
being made on the attachments so as to alter the angle of the boards at will
or if desired so as to give the necessary opening to the net, without giving undue
strain to either trawl warp or net.
The boards to which these attachments are fixed may be the ordinary otter
trawl boards, but preferably they are rounded from rear, the after end on the
lower edge to the fore end so as to have less resistance on the bottom of the
sea, and at the same time to allow the water to have its full power over the
boards, whilst they are being towed. The lower edge of the boards are weighted,
and shod with metal so as to keep them down only on the after end, thereby
giving as little resistance as possible, whilst they are being towed in an upright
and angular position with the trawl net attached.
In construction, they may be made preferably of light wood bound with iron,
or angle iron frame or Tangle frame, weighted, and rounded on the after end,
and rounded on the fore end, and plated with sheet iron or steel, or filled in with
thin hard wood or stout canvas, laced to the T iron frame. The pressure on
this type of board is not half so great as on the ordinary otter trawl board, owing
to the entire strain from the towing line to the net being direct through the
board, the only duty of the board being to open the net, and not to drag the
net from the board as in the ordinary type.
Figure 1, is a perspective plan of my improved trawl board d with attachments
placed on the back of the board for fastening the head line, and ground rope of
the net, and attachments on the front of the board for fastening the head line,
and ground rope of the net and attachments on the front of the board for fasten-
ing the towing line, shewing the lines of force f, f, passing through the board.
aal being attachments leading from the back of the board to the head line,
and ground rope of the net ; a, a, being chains with shackles to regulate the
angle of the board as shewn at e, e, which angle can be made greater or less at
will, by lengthening or shortening the chains marked a, a. The attachments
may be either chains, cords or ropes as desired; b, b, shews the towing attach-
ments on the front of the board leading to the trawl warp or towing line,
c weighted shoe to cause the board to sink on the after end making the board
very easily towed, and causing very little disturbance at the bottom of the sea
as the board by its weight on the after end, and the arrangement of its attach-
ments will only lightly touch the bottom.
Figure 2, side elevation of the same board.
Figure 3, side elevation of board with a hinged expanding bracket for regula-
ting angle on the back of the board at after end, and front attachment near
middle of board, with line of force f f passing through the board. The same
letters in Figure 1 apply to Figures 2, 3, & 4.
Figure 4 is a perspective plan shewing front of ordinary trawl board with
improved attachments a a placed on the back of the board, with lines of force f f
passing through the board. By means of these attachments this type of board
becomes much easier towed owing to the angle being fixed by the power, that
is exerted from the towing line being direct through the board to the net. The
board by being fitted with these attachments, the vessel may be stopped, and a
cast of lead, to find the depth of water, in which the vessel is trawling can be
taken, and when the vessel is started again (the board may fall down) but
immediately resumes its upright position owing to the resultant of force acting

page_text: through the board from the towing line to the head line, and ground rope of
the net these forces being nearly equal.
Having now described the nature of my said invention, and in what manner
the same may be performed I declare that what I claim is:
1. Trawl boards with attachments, placed on back and front of the boards,
so as to cause the lines of force between the towing line or trawl warp, and the
ground rope, and head line of the net to pass through the boards, keeping them
at the desired angle independent of the pressure of the water, all as particularly
described, and shewn in the accompanying drawings.
2. The arrangement of balancing, and slinging, and weighting the boards
causing them to tow in an easy upright, and angular position as described and
shewn in the accompanying drawings.
Dated this 21st day of February 1899.
E. EATON,
Agent for the Applicant.