Kongsberg Simrad EK80 - Where to Install the Transducer; Mount the Transducer Deep

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Wheretoinstallthetransducer
Asingleanswertothequestion"wheretoinstallthetransducer"cannotbegiven.
Thephysicallocationofthetransducerdependsonthevessel'sdesignandconstruction,
howthehullisshaped,andhowthewaterrunsalongthehull.Therearehowevera
numberofimportantguidelines,andsomeoftheseareevenconicting.
Note
Theinformationheremustbeconsideredasgeneraladvice.EachEK80installation
mustbehandledseparatelydependingonthehulldesignandtheotherelectricaland
mechanicalsystemsinstalledonthevessel.
Topics
Mountthetransducerdeep,page48
Avoidprotrudingobjectsnearthetransducer,page49
Mountthetransduceratforwardpartofhulltominimizetheeffectsfromtheow
boundarywaterlayer,page50
Keepthetransducerfarawayfromthepropellers,page51
Mountthetransduceratasafedistancefrombowthruster(s),page51
Summaryandgeneralrecommendations,page52
Mountthetransducerdeep
InordertoachievethebestpossibleEK80performance,mountthetransducerasdeepas
possibleunderthevessel’shull.
Thereareseveralreasonsforthisrecommendation.
Flownoise
Considerthesituationswhenthevesselisunloaded,andpitchinginheavyseas.The
vesselisridinghigh,andthebowmayevenbeliftedoutofthewater.Thiswillcausea
lotofairtofollowtheshapeofthehull.
Theupperwaterlayersoftheseacontainamyriadofsmallairbubblescreatedbythe
breakingwaves.Inheavyseastheupper5to10metresmaybelledwithair,andthe
highestconcentrationswillbenearthesurface.Airbubblesabsorbandreectthesound
energy,andtheymayinworstcasesblockthesoundtransmissionaltogether.
Cavitation
Cavitationistheformationofsmallairbubblesclosetothetransducerface.Thebubbles
appearbecausethelocalpressurebecomesnegativeduringpartsoftheacousticpressure
SimradEK80InstallationManual