Setting Up Sonar
Use the Sonar tab on the Main Menu to set up the Sonar Page.
To access the Sonar Tab:
Highlight the
Sonar
tab on the Main Menu.
Main Menu—Sonar Tab
Fish Symbols
—select how the Sonar Page shows underwater targets
and background information. Select
Off
to show all of the available
information about the underwater environment. Select a fish symbol
to show only the information related to that symbol.
Water Type
—select the proper water type you are boating in.
Because sound waves travel through fresh and salt water at different
rates, it is necessary to select the water type to ensure accurate
readings on the unit.
Depth Number
—select the efficiency of the digital depth update
rate.
Fast Update
updates quicker and is recommended for low-
noise water deeper than 50 feet.
Auto
is best for shallow water or
high-noise areas, has a slower screen update, and is best used if you
travel a wide variety of depths.
If the unit is unable to track the bottom for any reason, the digits in
the depth window flash on and off to alert you that the unit is not
tracking the bottom.
Map Split Sonar Detail
—select how much detail appears on the
Map Page with the sonar shown.
Full Range
shows data using the
Range
setting of the Sonar Page, regardless of
Zoom
or
Bottom
Lock
.
Maximum Detail
shows any
Zoom
or
Bottom Lock
data
from the Sonar Page.
Keel Offset
—enter the surface reading for the depth of a keel. This
makes it possible to measure depth from the bottom of your keel
instead of from the transducer’s location. Enter a positive number
to offset for a keel. It is also possible to enter a negative number to
compensate for a large vessel that can draw several feet of water.
The
Keel Offset
is reflected in the depth reading.
Transducer
—select the type of transducer that you are using. If you
are using a speed-capable transducer/sensor, select
Temp, Spd
.
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GPSMAP 378/478 Owner’s Manual
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