Setting the Water Temperature Offset

The temperature offset compensates for the temperature reading from a temperature sensor or temperature-capable transducer.

Measure the water temperature using the temperature sensor or temperature-capable transducer that is connected to the network.
Measure the water temperature using a different temperature sensor or a thermometer that is known to be accurate.
Subtract the water temperature measured in step 1 from the water temperature measured in step 2.

This value is the temperature offset. Enter this value in step 5 as a positive number if the sensor measures the water temperature as being colder than it actually is. Enter this value in step 5 as a negative number if the sensor measures the water temperature as being warmer than it actually is.
Complete an action:
- If the sensor or transducer is connected to the chartplotter or a sonar module, select > My Vessel > Temp. Offset.
- If the sensor or transducer is connected to the NMEA 2000^® network, select > Communications > NMEA 2000 Setup > Device List, select the transducer, and select Review > Temp. Offset.
Enter the temperature offset value calculated in step 3.

GPSMAP® Owner's Manual