Raymarine GPM400 Reference Manual page 104

Note: When multiple fishfinder windows are open, we recommend
you have the depth reading displayed in at least one
window.
Measuring depth and distance with VRM
You can use a Variable Range Marker (VRM) to determine the
depth and distance-behind-boat of an object. These markers con-
sist of a horizontal (depth) line and a vertical (distance-behind-boat)
line; each of which are marked with the appropriate measurement
and are controlled individually.
Note: VRMs set up in Fishfinder are unrelated to those set up in
Radar.
To make a measurement using VRM
1. Press the PRESENTATION softkey.
2. Press the VRM softkey.
3. Toggle to ON.
4. Pause the display to make it easier to position the VRM over the
object.
5. Take your measurements:
Measuring distance
e.g.
RANGE
49ft
and/or
Measuring depth
e.g.
DEPTH
10ft
Press to highlight
G-Series Reference Manual
1.56nm
Move range
marker over target
OK
To save
position
12ft
Move depth
marker over target
104
To return the marker to its previous position, press CANCEL.
Adjusting the scroll mode and speed
You can adjust the speed at which the display scrolls, but the same
section of the bottom is displayed regardless of scrolling speed. A
faster speed displays more detail. This is useful when you are look-
ing for fish. If you select a slower speed the information remains on
the display for longer.
The following options are available:
• Manual - This allows you to set the scroll speed as a percent-
age of the maximum scroll rate for that depth. The lower the
percentage, the slower the image will scroll. The default is man-
ual adjustment with a full speed scroll (100%).
To select the scroll mode and speed
1. Open the Fishfinder Setup Menu.
2. Set your preferred values in the Manual Scroll Speed setting.
Pausing scroll
You can pause the display to see a 'snapshot' of the image. When a
display is paused, scrolling stops but the depth indication continues
to be updated.Scroll pause/resume affects the frequency showing
on your display (both frequencies if two are selected) while other
displays continue to scroll.
This allows you to inspect a paused image, place waypoints or
VRMs, while the other frequency continues to scroll and detect fish.
To pause or resume scrolling
1. Press the PRESENTATION softkey.
2. Toggle settings on the SCROLL key.
3. Press OK.