Simrad GO XSE Series Operator's Manual page 176

176
Critical forward range and Critical depth
Critical Forward Range and Critical Depth are user-selected
thresholds that define a critical zone forward of your vessel.
If the alarm is turned ON and you travel into water shallow enough
to cross into the critical zone, the Critical Zone alarm is activated.
To receive Critical Zone alarms, enable the Forward range alarm in
the Alarm settings dialog. For more information about enabling
alarms, refer to "Alarms" on page 198.
You can show the critical warning zones on the image by activating
the Show zones menu option.
A
Critical zone
B
Warning zone
ForwardScan | GO XSE/XSR Operator Manual