Navman Using the Fish 4432/4433, Interpreting the display, Strength of echoes, Bottom types

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4 Using the FISH 4432/4433

This section explains how to interpret the sonar displays, when and why to use the different frequencies and how fish are detected

and displayed.

It also describes Gain and Range and shows examples of some of the different sonar displays. Also see section 1-2 How the FISH 4432/4433 works.

4-1 Interpreting the display

The sonar displays do not show a fixed distance

Strength of echoes

travelled by the boat; rather, they display a

The colors indicate differences in the strength

history, showing what has passed below the

of the echo. The strength varies with several

boat during a certain period of time.

factors, such as the:

 

 

The history of the sonar signal displayed

Size of the fish, school of fish or other object.

depends on the depth of the water and the

Depth of the fish or object.

scroll speed setting.

Location of the fish or object. (The area

In shallow water, the echoes have a short

covered by the ultrasonic pulse is a rough

distance to travel between the bottom and the

cone shape and the echoes are strongest in

boat. In deep water, the history moves across

the middle.)

the display more slowly because the echoes

Clarity of water. Particles or air in the water

take longer to travel between the bottom and

the boat. For example, when the scroll speed is

reduce the strength of the echo.

set to Fast, at depths over 600ft it takes about

Composition or density of the object or

2.5 minutes for each vertical line of pixels to

bottom.

move across the display, whereas at 20ft it

Note: Planing hulls at speed produce air bubbles

takes only about 4-5 seconds.

and turbulent water that bombard the transducer.

 

 

The scroll speed can be set by the user to

The resulting ultrasonic noise may be picked up by

display either a longer history with less fish

the transducer and obscure the real echoes.

information or a shorter history with more fish

 

 

details. See section 3-2 Setup > Sonar.

 

 

If the boat is anchored, the echoes all come

 

 

from the same area of bottom. This produces a

 

Soft bottoms

flat bottom trace on the display.

 

 

such as mud,

 

 

 

The screen shot shows a typical sonar display

 

weed and

with the Fish symbols turned Off.

 

sand show

 

 

 

as narrow

 

 

 

bands

Single fish

Hard bottoms

such as rock

Large

or coral

show as wide

school of

bands

fish

 

Small school

 

of fish

Bottom types

 

Bottom

Mud, weed and sandy bottoms tend to weaken

and scatter the sonar pulse, resulting in a weak

 

 

echo. Hard, rocky or coral bottoms reflect the

 

pulse, resulting in a strong echo. See section

 

5-3 Sonar Bottom display.

17

NAVMAN

FISH 4432/4433 Installation and Operation Manual

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Contents Pilot Contents Navman Benefits of the Fish 4432/4433 IntroductionBasic Operation How the Fish 4432/4433 worksKey Names Key Operation Power On / Auto PowerPower Off Backlight AdjustmentSetting up the Fish 4432/4433 Simulate ModeManual, Fishing and Cruising Modes Setup menu and options Factory reset Setup SystemAuto power off Backlight Snooze ModeDigit size Fish symbolsPulse power Scroll speedReset engine hours Setup LogsReset trip dist Reset total distFlashing light and/or external beeper Setup AlarmsAlarms automatically re-enable Setup UnitsNmea Out Setup Comms 4433 onlySetup Calibrate Nmea dataKeel offset TemperatureTemp filter FuelBottom types Using the Fish 4432/4433Interpreting the display Strength of echoesDepth 83 kHz 200 kHz Frequency and cone widthShadows Example of shadowsSingle and Dual frequency fishfinding When to use 200 kHz When to use 83 kHzAuto frequency 200/83 Khz display KHz displayFish detection and display Where to find fish Fish symbols OnFish arches Gain Changing between Cruising, Fishing and ManualObtaining the best results Changing the Range Mode RangeZoom Range and Zoom Offset Data header DisplaysDisplay menu Sonar displayBottom lock Sonar HistorySonar Zoom display ScopeSonar Bottom display Sonar 83/200 displaySonar A-Scope display Fish recognition Scope perspective viewFuel display 4433 only About display Data displayWire Function Wiring OptionsBasic wiring Nmea wiring Option Fish 4433 onlyThrough hull transducers Secondary alarm wiring option Fish 4433 onlyFuel kit wiring Fish 4433 only Auto power optionOptions and Accessories What comes with this product?Mounting and removing the display unit Systems of several instruments 4433 0nly Flush MountingRemoving the display unit Bracket MountingRepeat Cleaning and maintenanceSpecifications Fish Appendix a SpecificationsFishfinder won’t turn on Appendix B Dimensions Appendix C TroubleshootingBottom is displayed too far up the screen Fishfinder won’t turn offFishfinder operates erratically Bottom is not displayedThere is no reading for fuel economy Twin engine installation shows only one flow rateFlow indicates no fuel or low fuel Erratic Fuel Flow readingsOceania How to contact usFish 4 432 / 4