5FISH 4200 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 4200.
The NAVMAN Fishfinder
The FISH 4200 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 4200 measures the water depth, water
temperature and boat speed.
It also measures the battery voltage, engine hours,
and fuel consumption (requires optional fuel kit), and
has two distance logs (Trip Log and Total Log).
An installed FISH 4200 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 4200 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.
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 new
proprietary SBN Technology for sonar processing to
improve signal enhancement, bottom recognition & 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 4200 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 4200 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 4200 is installed and used
How to find fish
Underwater features like reefs, wrecks and rocky
outcrops attract fish. Use the FISH 4200 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.
For deep-sea fishing with the FISH 4200, a rapid
change in temperature may indicate the edge of a
warm or cold current. The temperature difference
can form a barrier, and the fish may not swim through
this. Search for fish on either side of the barrier.
Cleaning and maintenance
The FISH 4200 should be cleaned with a damp
cloth or mild detergent. Avoid abrasive cleaners and
petrol or other solvents. Always cover or remove a
transom-mounted transducer when repainting the
hull. If painting over a through hull transducer with
antifouling paint then use only one coat of paint.
When repainting the transducer, remove previous
coats of antifouling paint by sanding it lightly.
When not in use, the FISH 4200 can either be
removed from the installation bracket and stored
in a safe, dry, cool place such as the NAVMAN carry
bag, or left on the installation bracket and securely
covered with the sun cover supplied.