Navman Tracker500/500i User Manual page 7

digits are used for the degrees as longitudes can be as large as 180°. The E indicates this
location is east of Longitude 000°, a vertical line through Greenwich (London). If you don't
have a pair of dividers, you can use a ruler or even two pencil marks on the edge of a strip
of paper.
When entering the Lat/Lon of a waypoint from a chart, it is essential that the Tracker500/
500i is set to the same Lat/Lon datum that the chart uses (see section 15.0 Chart Datums).
This also applies if you are plotting the current boat position onto a chart. The datum will
be given in the chart's title block.
If you use waypoints from a chart, it is a good idea to clearly mark the waypoints on the chart.
Then, before you start navigating to a waypoint, you can draw a straight line from the boat's
current position to the waypoint and check that it doesn't pass too close to any rocks or
shoals. A similar idea is to enter any isolated rocks in your area as waypoints with the rock
symbol ( ). When you start navigation to a waypoint, the Tracker500/500i draws a line from
the current boat position to the waypoint on its Trackplot screen. By looking at this screen
you can check whether your intended course passes too close to any isolated rocks.
Fuel Functions
The fuel computer functions available in the Tracker500i enable you to keep track of how
much fuel you have used, how much you have remaining, the rate at which fuel is being
consumed, and how far you are travelling for every litre or gallon of fuel used. All this
information is shown on one screen. The fuel used value can be cleared to zero at any time
so that you can keep track of the amount of fuel used for each trip, or for each season, or
since you bought the boat, according to your preference. The fuel remaining value, on the
other hand, must be updated each time you refuel so that you always know how much fuel
is left in the tank. There is a low fuel alarm associated with the fuel remaining value that can
be set to warn you when the fuel in the tank falls below the alarm level. You can set the
alarm level to suit the size of the boat's engine and the distance you intend to travel.
The fuel consumption (titled FLOW on the screen) in litres or gallons per hour is shown. For
twin engine installations, the consumption for each engine is shown separately. This is
useful for checking that both engines are under the same load.
As the Tracker500i has both boat speed and fuel consumption values, it is able to calculate
the current economy rate. This is the distance the boat is travelling for every unit of fuel
used. The economy rate figure, depending on which distance unit and fuel volume unit the
Tracker500i is set to, will have units like miles per gallon or kilometres per litre. As the speed
error cause by Selective Availability becomes significant at low boat speeds, the economy
rate is not displayed for speeds of 5 knots or less. If the Tracker500i is receiving corrections
from a differential receiver, the economy rate is displayed whenever the boat speed is
above 1 knot.
Tracker500/500i User Manual 5