AUTOHELM ST 50 plus - Navigation Modes

3 .6 Dead Reckoning Mode
If
the ST50 Plus GPS/Navdata fails to receive
a
position signal
it
will sound
an alarm and display 'NO DATA' for 10 seconds .
If the vessels speed and heading is available on the SeaTalk bus, the GPS/
Navdata
will
automatically calculate
a
'dead
reckoned' position using
the
SeaTalk data . The display will automatically change
to
display a 'DR' (dead
reckoned) message .
If the position signal returns, the GPS/Navdata will automatically start to
operate normally .
When there is no position signal, all transmissions of waypoint information
will stop and the selection of track control is prevented .