Furuno NAVNET 1724C - Manual (Page 142)

4. VIDEO SOUNDER OPERATION
4-13
PICTURE ADVANCE
▲
¤ 2/1
¡ 1/1
¡ 1/2
¡ 1/4
¡ 1/8
¡ 1/16
¡ STOP
▼
Picture advance window
4. Use the Cursor pad to select speed desired. The fractions in the window denote the
number of scan lines produced per transmission. For example, 1/8 means one scan line
is produced every eight transmissions. STOP freezes the display and it is convenient for
observing an echo.
5. Press the RETURN soft key followed by the MENU key to close the menu.
Note: When using the plotter/sounder combination display, advancement of the sounder
picture may be temporarily interrupted while the plotter display is being shifted or its display
range is being changed.
4.9.2 Advancement synchronized with ship’s speed
With speed data provided by a speed-measuring device, picture advance speed may be set
according to ship’s speed, the ship’s speed dependent mode. As shown in the figure below
the horizontal scale of the display is not influenced by the change of ship’s speed, thus the
speed-dependent picture advance permits judgment of fish school size and abundance at
any speed. The choice “SPD SENSING PRR” means the ship’s speed dependent mode,
where the PRR changes automatically with ship’s speed.
FULL
SPEED
HALF
SPEED
Actual Movement
Same size
fish schools
Speed
Normal Mode
Speed-Dependent Picture Advance Mode
Fish school shrinks as speed
is increased; expanded
as speed is decreased.
Fish schools are shown
same size regardless
of ship’s speed.
How the speed-dependent picture advance mode works