Furuno GP-7000F - Manual (Page 92)

10. VIDEO SOUNDER OPERATION
10-6
Bottom-lock display
The bottom-lock display provides a compressed normal picture on the right half
of the screen and a 15 or 30 feet (5 or 10 meter) wide layer in contact with the
bottom is expanded onto the left half of the screen. This mode is useful for
discriminating bottom fish from the bottom echo.
Note:
The range of the bottom-lock display can be changed at BOTTOM LOCK
RANGE on RANGES menu.
50k
88.7
0
Single frequency
display
Fish school
Bottom-lock
display
Zoom marker
This part is
zoomed.
50
0
10
20
30
Fish
school
ft
100
0.0
Bottom-lock display plus normal sounder display
Bottom-zoom display
The bottom-zoom display expands bottom and bottom fish echoes by the chosen
zoom range and is useful for determining bottom hardness. A bottom displayed
with a short echo tail usually means it is a soft, sandy bottom. A long echo tail
means a hard bottom.
Note:
The range of the bottom-zoom can be changed at ZOOM RANGE on
RANGES menu.
50k
Single frequency display
Bottom-zoom display
Zoom marker
59.8
ft
Bottom
50
100
70
60
50
When depth changes,
the marker follows it automatically.
Bottom-zoom display plus normal sounder display