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Side-Imaging
Basics
Barry
Featheringill
After
the introduction of ‘Side
Imaging’ technology back in 2004 by Humminbird
that made the available to consumers technology that maps the
lake bottom in picture like detail. It is as if your boat is an
airplane looking down on the lake bottom and taking pictures. The
screen presentation is more like a monochrome photograph than what the
conventional screen presentation of conventional fish finders.
The
first units that Humminbird came out with this new innovative
technology uses technology derived from military and commercial
products to present the picture like detail. This technology prior to
Humminbird’s development of the 981c SI and the 987c SI Combo was
extremely expensive to use. Humminbird coupled this technology with
high performance and popular features to make available to consumers.
The
concept caught on and with the 900 series ‘Fishing Systems’ in
addition to be rather pricey the 900 Series unit are a lot larger in
physical size to what we are accustom to seeing in a conventional fish
finder. The price of almost two thousand dollars made it tough to be
able to say that it would be a good investment.
In
July of 2006 Humminbird after seeing the success of the 997 c SI
series Side Imaging units and seeing the number of anglers who wanted
the Side Imaging technology but did not have the space for the large
unit announced a new compact unit. This unit, the 797 c2 SI Combo
would meet the desire for Side Imaging with a compact unit.
The
797 c2 SI Combo unit made it to the shelves of retailers in December
2006. The fact that this unit in addition to being smaller in physical
size cost about half as much has made it a very poplar unit. The 797
c2 SI unit omits a single beam 86 degree beam at a frequency of 455
kHz giving 180 degrees of bottom coverage out to a range from six feet
to three-hundred-sixty feet to either one side of the boat or both
side.
How It Works
The
transducer for the Side Imaging units sends out a two-bladed signal at
eighty degrees to both sides, two other signals at different
frequencies are also sent out to cover the down looking center area
directly under the boat. One of these two beams looks at a twenty
degree cone area for precision viewing and the other is a seventy-four
degree cone for broader viewing looking for fish, bait or structure
under the boat. The signals’ beams are oriented so that it starts at
the surface and extends to below the boat giving a 180 degree
coverage.
At
the top of the image above at the center you see
icon that represents the boat position at time the
“snapshot” (term for image recorded) is taken . The returns from
the sonar coming from either side are represented on the corresponding
sides. The most current information is at the top and the oldest data
is at the bottom. When the sonar ping is first sent out it travels
down the water column represented by the dark area in the middle of
the screen. If there is structure, fish or other objects in the area
below the boat and slightly either side they will appear in this area.
The width of the “:water column” will vary with changes in depth
very much like traditional sonar expect turned 90 degrees. After
profiling the bottom contour below the boat Side Imaging looks out to
both side to define the bottom contours out to 360 feet either side of
the boat. The changes in depth are defined by shading.
Lighter shades refer to rises in contour and dark shades
represent descending terrain. Objects that are suspended off the
bottom like fish will not have a shadow adjacent to it, but there
maybe a shadow will away from the object.
Using
Side-imaging
Side
imaging offers the tournament angler and the recreational angler by
saving time in finding fish attracting cover and structure in a
shorter time than with traditional sonar or the use of search bait to
learn where the rocks and stumps are located. Once the angler finds
fish you can with the use of side-imaging and find a stump here and
another stump there and tie it to the bottom contour.
With
having to spend less time searching for cover and structure anglers
with the help of side-imaging will have more time to experiment with
lure choices and presentations. Side-imaging takes the guess work out
of offshore structure fishing.
Fish
show up as white spots on the screen of side-imaging and will become
clearer images at a closer distance with sensitivity increase.
Side-imaging does not define fish with as much definition as it
does a log. The technology
will show the position of fish along cover and structure making it
easier to determine lure selection.
Side-imaging
with it’s wide coverage makes finding schooling fish easier and it
will assist in determining the exact location of the schooled fish.
Another
advantage to side-imaging is the ability to find structure without
having to run over the top of it and spook any fish present.
All
of the side-imaging units are equipped with GPS which allows angler to
place cursor on the exact spot off to either side of the boat and
create (Mark) a waypoint. With a
traditional
sonar unit to find structure you have to run over the top of it. The
structure must be directly under the boat with the traditional sonar.
Side-imaging allows angler to be away from the structure and still
mark a waypoint on the exact spot. This technology works regardless of
the weather to see the tops of stumps or other structure that normally
would not be visible because of light conditions.
The
new side-imaging units also have the traditional sonar view, chart
view (navigation), real time sonar view, circular flasher view and
birds-eye view as well as several combination views that make them a
complete fishing system.
This
new technology now reveals structure that holds fish in a matter of
minutes that with traditional sonar takes some times hours. This
giving more time to the fun part of fishing…CATCHING.
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