Furuno NAVNET 1823C - Manual (Page 158)

4. VIDEO SOUNDER OPERATION
4-12
4.5 Measuring Depth, Time
The VRM measures the depth and the cross-hair cursor, time.
1. Rotate the [ENTER] knob to shift the VRM; counterclockwise to shift it
downward, clockwise to shift it upward. You may also use the trackball to
shift the VRM.
2. Roll the trackball horizontally to adjust the cross-hair cursor to measure time.
VRM (white)
40.0
Depth to VRM
Cross-hair
cursor
LF
97
150
200
50
100
0 0'33"
Time for a scan line to travel
from the right edge of the
display to the cross-hair cursor
How to measure depth and time
Note: If, when the range setting is over 1000 ft (m, fa, p/b), the VRM indication
and depth scale may overlap one another, shift the cross-hair cursor
slightly to show them completely. Further, when the display is shifted, the
depth scale may obscure the time indication.