Furuno FAR-2107(-BB) - Manual (Page 186)

4. AIS OPERATION
4-12
6. Select 6 AIS SCALED SYMBOL.
7. Select OFF or ON as applicable.
OFF: All AIS symbols shown in same size.
ON: All AIS symbols are scaled according to ships' lengths.
8. Push the right button three times to close the menu.
4.9 Past Position Display
The past position display shows equally time-spaced dots marking past positions
of activated AIS targets. A new dot is added at preset time intervals until the
preset number is reached. If a target changes its speed, the spacing will be
uneven. If it changes course, its plotted course will not be a straight line.
Note that AIS past positions will be shown if TARGET TRACK on the DISPLAY
sub menu of the PLOTTER menu is ON, regardless of whether AUTO TARGET
TRACK on the PLOTTER menu is turned ON or OFF.
Below are sample past position displays.
(a) Ship turning (b) Ship running
straight (c) Ship reduced
speed (d) Ship increased
speed
Sample past position displays
4.9.1 Past position plot interval
Left-click the PAST POSN box at the right side of the screen to select plot
interval desired: OFF, 30 s, 1, 2, 3 or 6 min. Select OFF to erase all past position
points and turn off the past position display.
PAST POSN REL 2MIN
PAST POSN box