Garmin 521 User Manual

Configuring the Chartplotter

  To set a sonar alarm from the Home screen, select 

 > 

 > 

.

NOTE: To configure sonar alarms, you must be receiving NMEA 

sonar depth data.
Shallow water—set an alarm to sound when the depth is less than 

the specified value.
deep water—set an alarm to sound when the depth is greater than 

the specified value.
water Temp—set an alarm to sound when the transducer reports 

a temperature that is 2°F (1.1°C) above or below the specified 

temperature.
fish—set an alarm to sound when the unit detects a suspended 

target of the specified symbols.

—sounds an alarm for all fish sizes.
—sounds an alarm for medium and large fish only.
—sounds an alarm for large fish only.

You can configure your chartplotter to sound an alarm when the total 

amount of remaining onboard fuel reaches the specified level.

NOTE: To receive fuel-level information, your unit must be 

connected to an external fuel sensor, such as the Garmin GFS 10.

1.  From the Home screen, select 

 > 

 > 

 > 

 > 

 (or 

).

2.  If you select 

On, use the 

 to indicate the fuel level at 

which the alarm should sound.

  To configure settings for your boat, from the Home screen, select 

 >

.

Keel Offset—offset 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. Enter a negative number to compensate for a large 

vessel that may draw several feet of water.

1.  From the Home screen, select 

 > 

 > 

.