TRACKFISH 6500
Installation and Operation Manual
32
NAVMAN
8-2 Interpreting the display
The sonar displays do not show a fixed distance
travelled by the boat; rather, they display a
history, showing what has passed below the
boat during a certain period of time.
The history of the sonar signal displayed
depends the depth of the water and the scroll
speed setting.
In shallow water, the echoes have a short
distance to travel between the bottom and the
boat. In deep water, the history moves across
the display more slowly because the echoes
take longer to travel between the bottom and
the boat. For example, when the scroll speed
is set to
Fast
,
at depths over 1000 ft (300 m)
it takes about 2 minutes for the data to move
across the display, whereas at 20 ft (6 m) it takes
only about 25 seconds.
The scroll speed can be set by the user to
display either a longer history with less fish
information or a shorter history with more fish
details (see section 17-3).
If the boat is anchored, the echoes all come
from the same area of bottom. This produces a
flat bottom trace on the display.
The screen shot shows a typical sonar display
with the Fish symbols turned
Off
.
Strength of echoes
The colours indicate differences in the strength
of the echo. The strength varies with several
factors, such as the:
• Size of the fish, school of fish or other
object.
• Depth of the fish or object.
• Location of the fish or object. (The area
covered by the ultrasonic pulse is a rough
cone shape and the echoes are strongest in
the middle.)
• Clarity of water. Particles or air in the water
reduce the strength of the echo.
• Composition or density of the object or
bottom.
Note:
Planing hulls at speed produce air
bubbles and turbulent water that bombard the
transducer. The resulting ultrasonic noise may
be picked up by the transducer and obscure
the real echoes.
The scroll speed depends upon the water
depth and scroll speed setting. See sections
17-3 and section 8-2, for more information.
The appearance of echoes displayed are
affected by:
•
the TRACKFISH settings (see sections 17-3,
8-5 and 8-6)
•
echoes (different fish types, different
bottom types, wrecks and seaweed; see
section 8-2)
•
noise (water clarity and bubbles; see
section 8-2).
Cruise, Fishing and Manual Modes
The TRACKFISH has three sonar operating
modes:
•
Cruising mode
: Use this when on the
move. The TRACKFISH automatically adjusts
its settings to compensate for water clarity
and to display the bottom.
•
Fishing mode
: Use this when fishing.
The TRACKFISH automatically adjusts its
settings to compensate for water clarity
and to best display fish, the bottom and
other details.
•
Manual mode
: Use this to fine-tune the
TRACKFISH settings by hand. Best results
are often achieved in manual mode, but
practice and experience are required to
obtain the optimum settings for different
conditions.
For more information about modes, see
sections 8-5 and 8-6.
Warning: Use the automatic Cruising
or Fishing modes when learning to use the
TRACKFISH or when travelling at speed.
