6
Fish 4430/4431 Installation and Operation Manual
Congratulations on choosing a NAVMAN
fishfinder. For maximum benefit, please read
this manual carefully before installation and
use.
This manual describes the installation and
operation procedures for the FISH 4430/4431.
The NAVMAN Fishfinder
The FISH 4430/4431 is an ultrasonic fishfinder
with four levels of greyscale. It provides
powerful software and a large, high-resolution
screen with a zoom facility and a choice of fish
symbols. As well as detecting fish, the FISH
4430/4431 measures the water depth, battery
voltage, engine hours and water temperature.
The Fish 4431 also measures boat speed and
has two distance logs (Trip Log and Total Log).
An installed FISH 4430/4431 has two parts:
- The transducer attached to the hull.
- The display unit.
The transducer generates an ultrasonic pulse
(sound that is above the hearing range of the
human ear), which travels down towards the
bottom, spreading out into a cone shape.
When the pulse meets an object, such as a fish
or the bottom, some of the pulse is reflected
back up towards the boat and is received by
the transducer. The depth of an object can be
calculated by measuring the time between
sending the pulse and receiving its echo.
The NAVMAN FISH 4430/4431 will detect
the bottom down to 600 feet (180 metres),
depending on the clarity of the water and the
type of transducer used.
The strength of an echo can vary for a number
of reasons. Larger fish usually return stronger
echoes, and so do fish in the middle of the
cone, where the pulse is strongest. Reasons
for weak echoes include the fish or object
being in deep water, turbid water or in the
edge of the cone where the pulse is weakest.
Turbid water scatters the ultrasonic pulse and
is difficult to ‘see’ through. Turbidity can be
caused by air in the water (e.g. from another
boat’s wake) or by mud in the water.
Important
It is vital to the performance of the fishfinder
that the transducer is installed in the best
location. Please follow the instructions in the
Transducer Installation manual very carefully.
All of the NAVMAN 4000 Series fishfinders use
proprietary SBN Technology for sonar processing to
improve signal enhancement, bottom recognition
and noise rejection. SBN Technology uses
the latest in digital adaptive filter algorithms
to enhance all returned signals. At the same
time, SBN Technology uses active noise control
to reject interference, which can often be
mistaken by fishfinders for true returns. Using
SBN Technology, the FISH 4430/4431 analyses
the reflections from each pulse, filters false
returns, and displays what is in the water under
the boat.
The distinctions between the four levels of
shading help the user to better interpret what
is in the water and what type of bottom is
under the boat.
Assisting with navigation
The FISH 4430/4431 can be used to find fish,
to locate features on the bottom such as reefs
or wrecks, and to help recognise favourite
fishing spots from the profile of the bottom.
Use the NAVMAN fishfinder to assist navigation
by following the depth contours marked on
charts.
IMPORTANT NOTE ON USE. While any fishfinder
can be used as an aid to navigation, accuracy
can be influenced by many factors including
the location of the transducer. It is the
user’s responsibility to ensure that the FISH
4430/4431 is installed and used correctly.
How to find fish
Underwater features like reefs, wrecks and rocky
outcrops attract fish. Use the FISH 4430/4431
to find these features, then look for fish by
passing over the feature slowly several times
using the ZOOM screen (see section 3-4).
Where there is a current, the fish will often be
found downstream of the feature.
1 Introduction
