Garmin gpsmap 720s ユーザーズマニュアル

Sonar

The keel offset compensates for the surface reading for the depth of a keel, making it possible to measure 

depth from the bottom of the keel instead of from the transducer location. Enter a positive number to offset for 

a keel. You can enter a negative number to compensate for a large vessel that may draw several feet of water.
1.  Complete an action, based on the location of the transducer:

•  If the transducer is installed at the water line 

➊

, measure the distance from the transducer location to 

the keel of the boat. Enter this value in step 3 as a positive number.

•  If the transducer is installed at the bottom of the keel 

➋

, measure the distance from the transducer to the 

water line. Enter this value in step 3 as a negative number.

➊

➋

2.  From the Home screen, select Configure > My Boat > Keel offset.
3.  Enter the distance measured in step 1. Ensure that you enter a positive or a negative number based on the 

location of the transducer.

4.  Select Done.
Setting the Water Temperature Offset

You must have a NMEA 0183 water-temperature sensor or a temperature-capable transducer to measure water 

temperature.
The temperature offset compensates for the temperature reading from a temperature sensor. 
1.  Measure the water temperature using the temperature sensor or temperature-capable transducer that is 

connected to the chartplotter.

2.  Measure the water temperature using a different temperature sensor or a thermometer that is known to be 

accurate.

3.  Subtract the water temperature measured in step 1 from the water temperature measured in  

step 2. 
This is the temperature offset. Enter this value in step 5 as a positive number if the sensor connected to the 

chartplotter measures the water temperature as being colder than it actually is. Enter this value in step 5 

as a negative number if the sensor connected to the chartplotter measures the water temperature as being 

warmer than it actually is.

4.  From the Home screen, select Configure > My Boat > Temp offset.
5.  Enter the temperature offset calculated in step 3.
6.  Select Done.