Furuno GP-1600F - Manual (Page 53)

3 – 3
Zoom displays
Three types of the zoom displays are available: bottom-lock, bot-
tom zoom, and marker zoom.
Bottom-lock
The bottom-lock expansion display provides a compressed normal
display on the right side and a "narrow" or "wide" layer (distance
depends on unit of measurement) in contact with the seabed onto
the rest of the screen with the seabed contour displayed by a straight
line on the bottom-lock display. This display offers excellent bot-
tom fish discrimination, which is vital for bottom trawling.
200k
162
0
50
100
150
200
68.3
CSE 180.0° SPD 16.8kt
DEP 113.6 ft TMP 16.0 °C
2D
12.0V
POS 34° 26.245' N 135° 41.232' E
Bottom-lock
display
Normal
display
Display
range
marker
0
10
20
30
40
50
Figure 3-4 Bottom-lock display
Note: For the bottom-lock expansion display, the seabed contour
must be steadily and distinctly plotted. Adjust the gain or select
automatic operation. You may select the bottom-lock expansion
range (wide or narrow) on the SOUNDER SETUP menu in the
SYSTEM menu.
Bottom zoom
The bottom zoom display expands bottom and bottom fish echoes
two, three, four or five times on the left half of the screen. The
zone expanded is indicated by the zoom range markers on the nor-
mal display.
The zone automatically moves so that the bottom echoes locate on
the lower half screen.
This mode is useful for observing hardness of the bottom closely
together with bottom fish. Many fishermen find the place where
bottom fish are likely to be, from the shape of bottom profile and
length of bottom echoes. The length of the bottom echo is an indi-