Raymarine e7, User Reference

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Fishfinder Transducer Calibration
Your fishfinder transducer must be calibrated correctly to achieve
accurate depth readings.
The multifunction display receives the image from a DSM which
processes sonar signals from a transducer mounted in the water.
If the transducer is equipped with a speed paddle wheel and
temperature-sensing thermistor, the DSM calculates speed and
temperature. To ensure accurate readings, it may be necessary to
calibrate the transducer(s) by applying offsets to depth, speed and
temperature. As these settings are held in the DSM and relate to
the transducer, they are applied system-wide.
Depth Offset
Depths are measured from the transducer to the sea bed, but you
can apply an offset value to the depth data, so that the displayed
depth reading represents the depth to the sea bed from either the
keel or the waterline.
Before attempting to set a waterline or keel offset, find out the
vertical separation between the transducer and either the waterline
or the bottom of the keel on your vessel, as appropriate. Then set
the appropriate depth offset value.
D9343--2
1 2 3
1 Waterline offset
2 Transducer / Zero offset
3 Keel offset
If an offset is not applied, displayed depth readings represent the
distance from the transducer to the sea bed.
Setting the depth offset
From the fishfinder application:
1. Select Menu .
2. Select Set-up .
3. Select Transducer Set-up .
4. Select Depth Offset .
5. Use the Rotary Control to adjust the offset to the required value.
Using the fishfinder
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