Garmin 521 User Manual

Using Sonar

When connected to a transducer, the following chartplotters can be 

used as fishfinders: 
GPSMAP 421s  GPSMAP 451s 

GPSMAP 521s  GPSMAP 526s 

GPSMAP 551s  GPSMAP 556s

Select the Full Screen option to view a full-screen graph of the 

transducer’s sonar readings. 

  From the Home screen, select 

 > 

.