Raymarine E Series User Reference Handbook page 190

Menu Item
Frequency Calibration
Depth Offset (waterline)
Speed Offset
Temperature Offset
190
Description
Fine tune the frequency of the transducer.
Offset represents the depth of the transducer (relative to the
waterline).
Offset applied to the speed log.
Offset applied to the temperature transducer value.
Options
Variable setting for the selected frequency.
–9.9 to +9.9 feet
0 to 100%
–9.9 to +9.9 °F
E-Series Widescreen User reference