The graphic depiction of the bottom provides the user with an effective tool for understanding the
composition of the bottom. If the bottom is hard and smooth, the bottom depiction is narrow and
dense. If the bottom is soft mud or sand, the depiction will be thick and less dense. This indicates
that much of the signal is absorbed by the soft bottom. If the bottom is rocky or rugged in
composition, the depiction is of varying density and textured in appearance.
Wave action also affects the bottom depiction. Remember that the information drawn is a
distance measurement, so if the boat is moving up and down over flat bottom, the bottom
depiction often appears in regular variations which match wave timing.
Structure is defined as any object physically attached to the bottom. The sonar configuration of
the Wide Portrait is optimized to give the most accurate depiction of bottom structure possible.
Grass, trees, stumps, wrecks or other debris are accurately displayed, however the depiction of
these objects varies with boat speed and direction. The best way to learn to interpret structure is
to operate the Wide Portrait over a variety of known conditions and experiment with user
functions to best represent those conditions on-screen.
Sonar targets which are not physically attached to the bottom may take one of many shapes.
Surface clutter is the layer of water near the surface which is rich in algae and other growth, and
often is aerated by wind or wave action. This area interferes with sonar transmission and often
appears on-screen as regular clusters of individual dots near the “O” line.
Summary of Contents for Wide Portrait
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