Specifications

Sonartheory
Thelevelyourreadinthebuttonisthecurrentnoiseinthedirectionofthecursor.
ThenoiseisprovidedindB,andthenumbershouldbeassmallaspossible.
Inordertoreducethenoise,trytoadjustthepropellerpitchandthenumberof
revolutions.
Howtocheckforelectricalnoise
Thisprocedureprovidesasimplemethodtochecktheelectricalnoise.
1Switchoffallelectricequipmentthatcancauseelectricalnoise.
Thisincludesmotor,propellers,thrusters,winches,cooling-andairconditioning
systems,pumps,cranes,hydraulicsystemsetc.
2Switchtheequipmentonagainoneatthetime,andcheckthesonareverytime.
Withluck,youwillspotwhichofyourelectricalsystemsthatcreatethenoise.To
dealwiththeproblem,consultyourdealerand/oracertiedshipselectrician.
Layersanddeections
Yoursonaroperationsmayalsobedisturbedbyenvironmentalsituationsthatyouare
unabletocontrol.Twotypicalconditionsaretemperatureandsalinitylayers,and
deectionscausedbyincreasingordecreasingwatertemperature.
Temperatureandsalinitylayers
Youmayexperiencethattemperatureand/orsalinitylayersexistinthewatercolumn.
Sincethespeedofsoundinwaterdependsonitstemperatureandsalinity,suchlayers
willcausethesoundbeamtobereected.
Figure9Temperatureandsalinitylayers
B
(CD015005F)
A
Ifyoutransmitasonarbeamdowntowardsatemperatureorsalinitylayer(A),itmay
bereectedasindicatedintheillustration.Theschoolofsh(B)youthoughtyou
wouldseewillnotbevisibleatall.
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