Garmin 400C - Page 20

4 Fishnder 400C Owner’s Manual
InstallIng the FIshFInder 400c
Because water is necessary to carry the sounder’s sonar signal, the
transducer must be in the water to work properly. You cannot get a
depth or distance reading when out of the water.
When you place your boat in the water check for leaks around
any screw holes that were added below the water line. DO NOT
leave your boat in the water for an extended period of time without
checking for leaks.
To test the transom mount transducer installation:
1. Begintestingtheinstallationataslowspeed.Ifthesonar
appearstobeworkingproperly,graduallyincreasethe
boat’sspeedwhileobservingthesonar’soperation.Ifthe
sonarsignalissuddenlylostorthebottomreturnisseverely
degraded,notethespeedatwhichthisoccurs.
2. Returntheboattothespeedatwhichthesignalwaslost.Make
moderateturnsinbothdirections,andseeifthesignalimproves.
3. Ifthesignalstrengthimproveswhileturning,adjustthe
transducersothatitextendsanother1/8"belowthetransom
oftheboat.Itmighttakeseveraladjustmentstoeliminatethe
degradation.
4. Ifthesignaldoesnotimprove,youmighthavetomovethe
transducertoadifferentlocation.
NOTE: When adjusting the depth of the transducer, make the
adjustments in small increments. Placing the transducer too
deep can adversely affect the boat’s performance and put the
transducer at greater risk of striking underwater objects.