Furuno NAVNET 1823C - Manual (Page 164)

4. VIDEO SOUNDER OPERATION
4-18
4.10.2 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
Activating/deactivating the speed-dependent picture advance mode
1. Press the [MENU] key followed by the SOUNDER MENU soft key.
2. Select PRR LEVEL.
3. Press the EDIT soft key to open the setting window.
4. Use the trackball
to select SPD SENSING PRR.
5. Press the RETURN soft key followed by the [MENU] key to close the menu.
Note: Use the same speed data sentence (STG or STW) throughout the network
for smooth advancement of the sounder picture. See the paragraph 6.5 for
how to output data through the network.