Navman Fish 4350, Installation And Operation Manual

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FISH 4350 / 4380 Installation and Operation Manual 16
NAVMAN
Note : Times indicated are for illustration only.
1 minute ago Now
Time
Stationary boat
When a boat is stationary, all bottom echoes will come from
the same small area of bottom. This will produce a
ß at bottom
trace on the screen.
The appearance of the Sonar and Zoom screens can
be changed to suit individual preferences.
4-2 Fish detection and display
Where to Þ nd Þ sh
Underwater features like reefs, wrecks and
rocky outcrops attract
Þ sh. Use the sonar to
Þ nd these features, then look for Þ sh by passing
over the feature slowly several times using the
Zoom display (see section 5-2 Sonar Zoom
display). If there is a current, the
Þ sh will often
be found downstream of the feature.
When fishing with the FISH 4350 and FISH
4380 with the Fish symbols
Off
, a weak fuzzy
band may appear between the bottom trace
and surface. This might indicate a thermocline
- a rapid change in water temperature, such
as the edge of a warm or cold current. The
temperature difference can form a barrier which
the
Þ sh may not swim through. In fresh water,
Þ sh often collect around a thermocline.
Fish symbols
The Þ sh symbol can be customized or
switched off altogether so that the echoes
are not converted to
Þ sh symbols on the
display. See section 3-2 Setup > Sonar. The
differences between Fish symbol
On
and
Off
are:
Fish symbols
On
Using Navman’s SBN sonar technology the
Þ sh Þ nder analyses all echoes and eliminates
most false signals and clutter so that remaining
targets are most likely
Þ sh. Depending on the
strength of
the remain-
ing echoes,
they are
displayed as
either small,
medium or
large
Þ sh
symbols
- with or
without
depth. While
the SBN
process-
ing is very
sophisticated
it is not foolproof - there will be times when
the
Þ sh Þ nder will not be able to differentiate
between large air bubbles, rubbish containing
air,
Þ shing ß oats etc. and Þ sh.
The following picture shows the Sonar display with
the Fish symbol:
On + depth
:
Fish symbol
Off
For experienced users this always provides the
best information as every echo is displayed,
whether it is surface clutter, a thermocline or
a
Þ sh.
The picture in section 4-1 Interpreting the
display, shows the Sonar display with the Fish
symbols
Off
. The Þ sh appear as arches.