Pennsylvania Angler & Boater - September/October 2019 - 39

A look, via Navionics Chart Viewer, at a section of Pymatuning Reservoir, Crawford County, rich in roadbeds, bridges and foundations.

As with any sonar picture, it takes time on the water to
interpret the views that side imaging provides. Here are some
tips to help aid the process:
* Keep the boat moving at about 5 mph when you are
specifically looking for bottom features. This speed
gives a better representation of the dimensions of
displayed items.
* Scan out to greater distances when generally looking, but
reduce the distance when you are looking at specific spots
to get better detail.
* When looking at a specific area, perhaps what may appear
as old foundation, look at it from various angles, which
will provide a better idea of what is below the surface.
* Adjust your unit's sensitivity settings to get the best
possible picture.

Down imaging

Like side imaging, down imaging shoots razor-thin
beams, providing a different look at what is below the boat
than traditional 2-D sonar. Often, you can see the actual
shape of weed stalks or tree branches on the bottom. I find it
advantageous to display both traditional and down imaging

side by side on the screen, so views can be compared to arrive
at a more accurate interpretation of what is being read.

Electronic charts

Marine electronics makers and third-party mapping
companies are providing better electronic charts for lakes in
Pennsylvania. Some are available as phone apps as well. Not
only are more accurate and detailed depth contours available,
but bridges, roads and foundations are shown as well in some
cases. With apps, you can do your research from your phone
or computer, transferring latitude/longitude coordinates
as waypoints to your chartplotter. Armed with the general
location of, say a submerged bridge, you can then give the
spot a closer look with side imaging to see what kind of fishattracting character is in the area, and pin the location down if
it is good.
Detailed maps are not available for all lakes in Pennsylvania,
particularly smaller ones, but the makers of all three of the
most popular sonar/chartplotters now feature models where
you can create your own maps. Such maps, with 1-foot
contours, are extremely accurate.

Online resources

Two online resources are valuable for unlocking hidden
treasures. One is the fish habitat section found on PFBC's
website, www.fishandboat.com, where you can access,
download and print lake maps that show the locations (with
coordinates) of habitat improvement structures. Also, look
at lakes on Google Earth, particularly lakes that are drawn
down during the winter. This website provides the locations of
bottom features.

Putting it all together
A comparison of emerging weed growth on traditional sonar (left)
and down imaging (right).
www.fishandboat.com

Combining the various sonar and mapping views may
unlock hidden treasures. Purchase a unit with a relatively large
screen, so you can split the screen up in combinations that
work best for you and still have good detail.

Pennsylvania Angler & Boater * September/October 2019

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Pennsylvania Angler & Boater - September/October 2019

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