Understanding The Fishfinder Card - Raymarine Marine RADAR Operating Manual

What's under the boat?
Understanding the fishfinder
Card 18
What's under the boat?
The fishfinder application, when connected to a suitable Digital Sounder Module (DSM) and transducer, will help
you to see fish, bottom structure and underwater obstructions. The image scrolls from right to left at an
automatically selected range and frequency to provide a record of the echoes seen. You can mark with a waypoint
any positions of interest that you may wish to return to. These waypoints are added to the waypoint list and can be
used by other applications.
What can I see on the screen?
Transducer Mode
SINGLE
Frequency
F1: 200 kHz
Bottom
ADJUST P1
SINGLE...
How do I interpret the bottom?
A thin line indicates a hard
bottom (sand)
Dark layers indicate strong signals; lighter layers weaker signals.
What influences target display?
The shape and size of echoes indicating targets, is influenced by a combination of:
Boat speed - flatter at slower speeds
Target depth - larger near the surface
?
More information...
Adjust P1
SINGLE
Frequency modes
Freq1: 200KHz-Auto
50
PRESET 2 PRESET 3
DUAL SHALLOW
A wide line indicates a soft
bottom (mud or seaweed cover)
Transducer frequency - broader at lower frequencies
Target size - larger targets return larger echoes
See the 'Using the Fishfinder' chapter of the Reference Manual.
PRESET 2 PRESET 3
DUAL SHALLOW
Freq2: None
68
69
PRESET 4
PRESENTATION...
DEEP
Peaks and troughs, indicate an
uneven or rocky bottom or a wreck
PRESET 4
PRESENTATION
DEEP
Bottom of
transducer
Depth
markers
Target
depth
Target
Bottom
depth