Simrad SU90 - Page 55

Preparations
2Echosoundertransducersshouldbemountedwithasmallinclinationangle.
3Thetransducermustbeprotrudingfarenoughdowntoreachoutoftheboundary
layer.
4Thehullplatinginfrontofthetransducermustbeassmoothaspossible.No
extrudingobjectsoranyabrupttransitionsshouldappear.Beespeciallyawareof
bilgekeelsandzincalloyanodes.Thekeelshouldberoundedoffwithoutsharp
edges.
Reducingmachinerynoise
1Thesonarhullunitshouldbeinstalledfarawayfromengineroom.
2Themainengineandrelevantauxiliaryenginesandequipmentshouldbexedto
rigidfoundationstoavoidvibrations.Useofshockabsorbersoroatingraftsmay
sometimesreducethisnoise.
3Anyhullstructurethatmayvibrateshouldbedampedorcoatedtoreducethe
vibrations.
4Thestructure-bornenoisemaybereducedbyisolation,forexamplebyproviding
vibrationclampingbetweenthetransducerandthehullstructure.
Reducingpropellernoise
1Thehullunitshouldbeinstalledasfarawayfromthepropellersaspossible.
2Sufcientclearancebetweenthepropellersandthehull,therudderandthekeel
shouldbeprovided.
3Placethezincalloyanodesinplaceswherethewaterowistheleastdisturbed.
4Ensurethatthepropellersbladesarecorrectlydesignedandwithoutdamages.
5Theuseofabafebetweenthepropellersandthetransducermayreducenoise
appreciably.
6Staticdischargescausedbytherotatingpropellershaftmayberemovedbyproper
groundingorbymountingacoalbrushfromtheshafttoground.
Reducingrattlenoise
Ensurethatnopartsnearthetransducercanrattleasaresultofwateroworvibrations.
Reducinginterference
Interferencefromthetransmissionpulsesfromotherhydroacousticinstrumentsonboard
thevesselisdifculttoavoid.
Theproblemmaybereducedbychoosingtheworkingfrequenciescarefullyandtosome
extentbyseparatingthedifferenttransducers.
Onvesselswithalargenumberofseparatehydroacousticsystemsinstalledandin
simultaneoususe,aseparatesynchronizingsystem(forexampletheK-Sync)should
beconsidered.
381293/A
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