Raymarine 420D Marine GPS System User Manual


 
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RayChart 420/420D Chartplotter
BDI display
The BDI display shows deviation from the bearing to waypoint and distance to
waypoint. Cross track Error, Bearing to Waypoint, Distance to Waypoint, Time
to Go, COG and SOG are also shown. Time to Go is calculated on the basis of
distance to destination and velocity made good towards destination.
D4701_1
The line to the waypoint symbol is shown at an angle equal to the difference
between the COG and the Bearing to Waypoint. The waypoint symbol is the
symbol of the target waypoint as seen on the chart.
The range scale automatically scales for distance. The ranges shown are 4nm,
20nm, 40nm, 100nm, 200nm, 400nm, 1000nm, 2000nm, 4000nm. In each case
the range scale has graduations at ¼, ½ and ¾ of the current scale.
The steering instruction is STEER STARBOARD if the waypoint line is 1° or
more to port, STEER PORT if the waypoint line is 1° or more to starboard or
ON COURSE if the waypoint line is dead ahead. If no GOTO or follow is in
progress, the steering instruction is NO TARGET, no steering arrows are
shown, but the rhumb line indicator is shown.
The graphical XTE indication will place arrows either side of the steering
instruction and pointing towards it dependent on the difference between COG
and bearing to Waypoint. The first arrow is shown when the difference reaches
5° and thereafter at 5° intervals.