Preparations
Athwartshipslocation
ThehullunitmaybelocatedontheCentreLine(CL)ofthevessel,oralongsideitskeel.
Note
Iftheinstallationisoffsetfromthevessel’ scentreline,makesurethattransducer
transmissionandreceptionwillnotbeobstructedbythekeel.
Importantconsiderationsrelatedtonoise
Theinstallationtrunkmustbeinstalledsothatitwillremainverticalundernormal
operatingconditions.Theprimarysourcesofunderwaterdisturbance(otherthana
vessel’smainpropellerandbow/sternthruster)thataffectSU90receptionare:
•Mainorbilgekeels
•Zincanodes
•Coolingelementsprotrudingfromthehull
•Equipmentsuchassonartransducersandpilottubes
•Seachests
•Overboarddischarges
•Dentsinthehull
Allappendagestothehull,indentationsandpipein/outletsarepotentialsourcesof
underwaternoise.Theymayactasresonantcavitiesamplifyingnoiseatcertain
frequencies,createcavitationorturbulence.Transducersshouldnotbelocatedinthe
vicinityofsuchobjectsandespeciallynotimmediatelyaftofthem.
Relatedprocedures
•Acousticnoiseonpage47
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