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EM 124
Installation Manual
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Konsberg EM 124 Installation Manual

KongsbergEM124
MultibeamEchoSounder
InstallationManual
Image:BathymetryoftheNorthernPortionoftheMarianaTrench.
CourtesyofDrJamesV .Gardener ,UniversityofNewHampshire.
443140/A
March2019©KongsbergMaritimeAS
Documentinformation
•Product:KongsbergEM124
•Document:InstallationManual
•Documentpartnumber:443140
•Revision:A
•Dateofissue:11March2019
Copyright
TheinformationcontainedinthisdocumentremainsthesolepropertyofKongsberg MaritimeAS.Nopartofthisdocumentmaybecopiedorreproducedinanyformorby anymeans,andtheinformationcontainedwithinitisnottobecommunicatedtoathird party,withoutthepriorwrittenconsentofKongsbergMaritimeAS.
Warning
Theequipmenttowhichthismanualappliesmustonlybeusedforthepurposefor whichitwasdesigned.Improperuseormaintenancemaycausedamagetothe equipmentand/orinjurytopersonnel.Y oumustbefamiliarwiththecontentsofthe appropriatemanualsbeforeattemptingtooperateorworkontheequipment.
KongsbergMaritimedisclaimsanyresponsibilityfordamageorinjurycausedby improperinstallation,useormaintenanceoftheequipment.
Disclaimer
KongsbergMaritimeASendeavourstoensurethatallinformationinthisdocumentis correctandfairlystated,butdoesnotacceptliabilityforanyerrorsoromissions.
Supportinformation
Ifyourequiremaintenanceorrepair,contactKongsbergMaritime’s supportorganisation.Youcanalsocontactususingthefollowingaddress:
km.hydrographic.support@kongsberg.com.Ifyouneedinformationaboutourother
products,visithttps://www.km.kongsberg.com.
KongsbergMaritimeAS
InstallationManual
Tableofcontents
ABOUTTHISMANUAL..............................................................7
KONGSBERGEM124................................................................9
Systemdescription...........................................................................................................10
Technicaldetails...............................................................................................................11
Systemdiagram................................................................................................................12
Systemunits.....................................................................................................................13
Transducerdescription...........................................................................................13
TransmitterUnitdescription...................................................................................14
ReceiverUnitdescription.......................................................................................14
ProcessingUnitdescription....................................................................................14
HydrographicWorkStationdescription.................................................................15
Supportinformation.........................................................................................................16
PREPARATIONS.....................................................................17
Tools,equipmentandconsumablesrequiredforEM124installation.............................17
Personnelqualications...................................................................................................18
Sonarroomrequirements.................................................................................................19
Environmentalrequirements..................................................................................19
Sizeandaccessrequirements.................................................................................19
Requirementsforinsulation,heatingandventilation.............................................20
Requirementsforelectricalinstallations,cablesandcommunication...................20
Wheretoinstallthetransducer........................................................................................22
Introductiontotransducerlocation.........................................................................22
Mountthetransducerdeep.....................................................................................22
Avoidprotrudingobjectsnearthetransducer.........................................................23
Keepthetransducerfarawayfromthepropellers.................................................24
Mountthetransduceratasafedistancefrombowthruster(s)...............................24
Summaryandgeneralrecommendations...............................................................24
Acousticnoise..................................................................................................................27
Contributingfactors................................................................................................27
Selfnoise................................................................................................................28
Ambientnoise.........................................................................................................31
Electricalselfnoise................................................................................................31
Somemeanstoreduceacousticnoise....................................................................31
INSTALLINGTHETRANSDUCER.............................................34
Transducerdescription.....................................................................................................35
Transducerinstallationprinciples....................................................................................37
Introduction............................................................................................................37
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KongsbergEM124
Gondola..................................................................................................................39
Blister.....................................................................................................................40
Flushmounted........................................................................................................41
Externalmountedwithfairings..............................................................................41
Transducerinstallationsummary.....................................................................................43
Manufacturingandinstallingthecasings........................................................................46
Designing,manufacturingandmountingthesteelconduits............................................48
InstallingtheRXmountingframe...................................................................................52
InstallingtheTXmountingframes..................................................................................55
InstallingtheRXTransducersintothemountingframes................................................57
InstallingtheTXTransducersintothemountingframes................................................60
Rulesfortransducerhandling..........................................................................................63
Paintingthetransducerface.............................................................................................65
Approvedanti-foulingpaints...........................................................................................67
INSTALLINGTHEEM124HARDWAREUNITS.........................69
TransmitterUnit...............................................................................................................70
InstallingtheTransmitterUnit...............................................................................71
RIO-Pboard-dipswitchsetting............................................................................73
ReceiverUnit...................................................................................................................74
InstallingtheReceiverUnit....................................................................................75
ReceiverUnit-dipswitchsetting..........................................................................77
ProcessingUnit................................................................................................................78
InstallingtheProcessingUnit.................................................................................78
ProcessingUnitrearpaneldescription...................................................................80
ProcessingUnitcircuitboardsandmodules..........................................................81
CBMFboard-dipswitchsetting...........................................................................82
InstallingtheHydrographicW orkStation.......................................................................83
InstallingtheHydrographicW orkStation..............................................................83
HydrographicWorkStationrearconnectors..........................................................86
CABLELAYOUTANDINTERCONNECTIONS.............................88
Cableplans.......................................................................................................................89
Cableplan,ProcessingUnit...................................................................................90
Cableplan,TransmitterUnit..................................................................................91
Cableplan,ReceiverUnit,1degree.......................................................................99
Synchronizationoverview,2TransmitterUnits1ReceiverUnit.........................102
Remoteon/offoverview,2TransmitterUnits1ReceiverUnit............................103
HydrographicWorkStation..................................................................................104
ListofEM124cables....................................................................................................105
Clocksynchronization(1PPS).......................................................................................109
Externalsynchronization...............................................................................................111
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Cabledrawingsandspecications.................................................................................114
RS-232seriallineusingthreewiresandRJ45connector....................................115
RS-422seriallineusingvewiresandRJ45connector......................................116
Clocksynchronisation(1PPS)usingacoaxcable...............................................117
Externalsynchronisation......................................................................................118
Remotecontrol.....................................................................................................119
RemoteControlusingK-Rem..............................................................................120
Dummyplugfornotusingremotecontrol...........................................................121
RemotecontrolofTransmitterUnit.....................................................................122
RemotecontrolofReceiverUnit..........................................................................124
Remotecontroloverview.....................................................................................126
TransmitTransducercable...................................................................................128
ReceiveTransducercable.....................................................................................129
DIMENSIONALSURVEYINGANDALIGNMENT......................130
Aboutdimensionalsurveyingandalignment................................................................131
Dimensionalsurveying..................................................................................................131
Alignment......................................................................................................................132
Transducerarrayatness...............................................................................................133
Checkingthetransducerarrayatnessandcorrectingdeviations.................................134
Calibration.....................................................................................................................135
Vesselcoordinatesystem...............................................................................................135
TECHNICALSPECIFICATIONS..............................................137
Performancespecications............................................................................................138
Interfacespecications...................................................................................................140
Datagramformats.................................................................................................141
ProcessingUnit.....................................................................................................142
Externalsensorsrequirements..............................................................................145
HydrographicWorkStation..................................................................................146
Weightandoutlinedimensions......................................................................................147
Powerrequirements.......................................................................................................150
Environmentalrequirements..........................................................................................152
Dimensionalsurveyaccuracyrequirements..................................................................155
Alignmentspecications................................................................................................157
DRAWINGFILE....................................................................158
Drawingnumbersreferencedinthisdocument.............................................................158
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KongsbergEM124
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Aboutthismanual
Purposeofmanual
Thepurposeofthismanualistoprovidetheinformation,proceduresandbasicdrawings requiredforthephysicalinstallationoftheEM124.
Targetaudience

Aboutthismanual

Themanualisintendedfortechnicalpersonnel;suchasskilledshipyardworkers, electricians,qualiedengineersandnavalarchitects.Itisassumedthatyouunderstand thegeneralprinciplesofmaritimeelectronicequipment.Y oumustalsobefamiliarwith computerhardware,interfacetechnologyandinstallationofelectronicandmechanical products.
Weassumethatyouarefamiliarwiththebasicacousticprinciplesofsoundinwater. Wealsoexpectthatyouhavesomeexperiencewithmultibeamand/orsinglebeamecho soundersinhydrographicapplications..
Installationinstructions
Youmustfollowtheinstructionsinthismanualtoensureoptimalperformance.Asa guide,installationproceduresarepresentedintheordertheymustbedone.
Theequipmentdescribedinthismanualincludesthecompletesystemwithrelevant cabinets.Unitsprovidedlocallybythecustomer,installationshipyardorlocal representativearenotdescribed.
Themanualalsodenestheequipmentresponsibility,andprovidesapplicable instructionsforunpackingandstorageofunits.
Note
Youmustfollowtheinstructionsgiveninthismanual.Ifnotitmayaffectthewarranty.
KongsbergMaritimeASwillacceptnoresponsibilityforanydamageorinjurytothe system,vesselorpersonnelcausedbyequipmentthathasbeenincorrectlyinstalledor maintained,orbydrawings,instructionsorproceduresthathavenotbeenprepared byus.
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KongsbergEM124InstallationManual
Installationdrawings
Theinstallationshipyardmustprovideallnecessaryinstallationdrawingsunless otherwisespeciedinthedeliverycontract.
KongsbergMaritimeASmay,onspecialorder,provideassistancetothesedrawings.
Note
Ifrequired,alldocumentsprovidedbytheshipyardforthephysicalinstallationof theEM124mustbeapprovedbythevessel’ snationalregistryandcorresponding maritimeauthorityand/orclassicationsociety.Suchapprovalmustbeobtainedbefore theinstallationcanbegin.Theshipownerandshipyarddoingtheinstallationare responsibleforobtainingandpayingforsuchapproval.
TheoutlinedimensionsoftheEM124unitsarefoundintheDrawinglechapter inthismanual.
Onlineinformation
ForinformationabouttheEM124andotherproductsfromKongsbergMaritime,visit ourwebsite.
•https://www.km.kongsberg.com
Registeredtrademarks
Observetheregisteredtrademarksthatapply.
Windows
®
isaregisteredtrademarkofMicrosoftCorporationintheUnitedStatesand
othercountries.
®
EM
isaregisteredtrademarkofKongsbergMaritimeASinNorwayandothercountries.
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Topics
Systemdescription,page10
Technicaldetails,page11

KongsbergEM124

KongsbergEM124
Systemdiagram,page12
Systemunits,page13
Supportinformation,page16
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KongsbergEM124InstallationManual

Systemdescription

EM124multibeamechosounderisahighperformanceechosounderfordeepwater mapping.
TheEM124isdesignedtoperformseabedmappingtofulloceandepthwithan unsurpassedresolution,coverageandaccuracy .Thesystemiscosteffective,reliable, andeasilyoperated.ThedesignoftheEM124isbasedonmorethan50yearsof hydrographicexperiencewithechosounders,sonarsandunderwaterpositioningfor civilianandmilitaryuse.Itisthelatestmodelinaseriesofdeepseamultibeamecho soundersthatstartedwiththeEM12in1990.
TheEM124consistofnewstate-of-the-artelectronicsandseparatetransmitandreceive transducersinaMillsCrossconguration.Itusesthesameeld-proventransducersas theEM122,makingiteasytoupgrade.Carehasbeentakentodesignahighly,modular andexiblesolutionwithcompactelectronicsforeasierandfasterinstallation.Duetoa exibletransducerdesign,thesystemcanbetailoredtoalmostanyrequiredsize.The largeststandardsize,0.5x1degrees,givestheultimatesystemperformanceintermsof resolutionandrange,whileasmaller4x4degreessolutionallowingfulloceandepth surveysevenonsmallervessels.
TheEM124multibeamechosounderconsistsofthefollowingmainunits.
•Transducerarrays
•TransmitterUnit(s)
•ReceiverUnit(s)
•ProcessingUnit
•HydrographicW orkStation
Toformacompletesystemitisalsorequiredtohavesensorsprovidingvesselattitude, velocity,position,soundspeedproleofthewatercolumnandspeedofsoundatthe transducerdepth.
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Technicaldetails

TheEM124operatesatsonarfrequenciesinthe10.5-13.5kHzrange.Thetransmitfan isdividedinto4sectorsinshallowmodes(8sectorsindeepmodes)tomaximizerange capabilitybutalsotosuppressinterferencefrommultiplesofstrongbottomechoes. Thesectorsaretransmittedsequentiallywithineachping,andusesdistinctfrequencies orwaveforms.
Thenominalsonarfrequencyis12kHzwithanangularcoveragesectorofupto150 degreesand1600beamsperping.Achievableswathwidthonaatbottomwillnormally beupto6times(143degrees)thewaterdepth.Theangularcoveragesectorisoperator controllableormaybesettoaxedrange.Itmayalsobesettovaryautomaticallywith depthaccordingtoachievablecoverage.Thismaximizesthenumberofusablebeams. Thebeamspacingisnormallyhighdensityequidistantwithequiangleavailable.
Thetransmitfanissplitinseveralindividualsectorswithindependentactivesteering accordingtovesselroll,pitchandyaw.Thisplaceallbeamsona“bestt”toaline perpendiculartothesurveyline,thusensuringauniformsamplingofthebottomand 100%coverage.
Indualswathmodethetransmitfanisduplicatedandtransmittedwithasmalldifference inalongtracktilt.Theappliedtilttakesintoaccountdepth,coverageandvesselspeedto giveaconstantbeamseparationalongtrack.
ThesectorsarefrequencycodedorhaveFMchirps,andtheyaretransmittedsequentially ateachping.Thesectorsteeringisfullytakenintoaccountwhenthepositionanddepth ofeachbeamiscalculated,asistherefractionduetothesoundspeedprole,vessel attitudeandinstallationangles.Thepulselengthandrangesamplingratearevariable withdepth(autoormanual)forbestresolution.
Inshallowwatersduecareistakentotheneareldeffectsthroughneareldfocusing individuallyappliedinthedifferentsectors.
EM124appliesonefocusrangeforeachofthetransmitsectorswhichareusedfor shallowwaterenvironment.Dynamicbeamfocusingisusedforthereceptionbeams.
Thepingrateismainlylimitedbytheroundtriptraveltimeinthewateruptoaping rateofmorethan5Hz.
ThenumberofindividualTXandRXmodulesinthetwoarraysdependsonthechosen conguration.Thestandardtypesidentiedby"transmissionxreception"beamwidth are:
•0.5x1degreesystem:96transmittransducermodulesand16receivetransducer
modules
•1x1degreesystem:48transmittransducermodulesand16receivetransducermodules
•1x2degreessystem:48transmittransducermodulesand8receivetransducermodules
•2x2degreessystem:24transmittransducermodulesand8receivetransducermodules
•2x4degreessystem:24transmittransducermodulesand4receivetransducermodules
•4x4degreessystem:12transmittransducermodulesand4receivetransducermodules
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Systemdiagram

ThesystemdiagramidentiesthemaincomponentsofabasicEM124system.Only themainconnectionsbetweentheunitsareshown.Detailedinterfacecapabilitiesand powercablesarenotshown.
AHydrographicW ork
Station
BInterfaces:
•Soundspeed
sensors
•Tide
•Centredepth
output
CProcessingUnit
DInterfaces:
•Positioning
systems
•Attitude(roll,
pitchandheave)
•Soundspeed
sensor
•Velocity
•Clock
•Trigger
input/output
•Clocksynchronisation(1PPS)
ETransmitterUnit(TXU)
FReceiverUnit(RXU)
GTransmittransducermodules
HReceivetransducermodules
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Systemunits

Topics
Transducerdescription,page13
TransmitterUnitdescription,page14
ReceiverUnitdescription,page14
ProcessingUnitdescription,page14
HydrographicWorkStationdescription,page15

Transducerdescription

KongsbergEM124
Atransducerisadevicethatconvertsoneformofenergytoanother.Inanechosounder systemthetransducerconvertsbetweenelectricenergyandsound.
TheEM124usesseparatetransducerarraysfor transmittingandreceivingsoundpulses.Both transducerarrayshaveseveralmoduleswhichare assembledinmountingframes.
Thetwotransducerarraysarenormallymountedas “T”or“L”congurationsunderthevessel’shull(Mills Crossconguration).Thetransmittransducerarray
Receivetransducermodule
shouldbealignedparalleltothevessel’skeel.The receivertransducerarrayshouldbealigned90degreesonthekeel.Bothtransducer arraysshouldbehorizontalonaplaneonthekeel.
Thetransmittransducerarraycontainsupto96modulesinaccordancewiththechosen beamwidth.Eachmodulecontains18elementsarrangedinrowsof6elements.Each elementisindividuallyconnectedtoitscorrespondingtransmitterintheTransmitter Unit(s).Itcanthusbedrivenwithanuniqueamplitudelevelandphasetoallowforming oftherequiredtransmitsectorswithindividualsteering.
Thereceivetransducercontainsupto16modulesinaccordancewiththechosen beamwidth.Eachmodulecontains8transducerstaves,andthesehaveindividual electricalconnectionstotheircorrespondingpreampliersintheReceiverUnit(s).Each stavecanthusbegivenuniqueamplitudeandphasecontroltoallowformingofthe requiredreceivebeams.
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TransmitterUnitdescription

TheEM124TransmitterUnithasalltransmitelectronics,likecontrolprocessors,power ampliers,powersupply,capacitorbatteryandEthernetinterface.
TheTransmitterUnitisawall-mountedsteelcabinetwithintegratedshockandvibration absorbers,designedforbulkheadmounting.One19inchsub-rackiscontainedinthe cabinet.Thenumberofcircuitboardsinthesub-rackwilldependuponthechosen transducerconguration.
TwistedpairEthernetisusedfordatacommunicationwiththeProcessingUnit.
TheTransmitterUnitisnormallylocatedina"sonarroom"closetothetransducerarrays.

ReceiverUnitdescription

TheEM124ReceiverUnithasallreceiveelectronics,likecontrolprocessor,ampliers, Analog-to-DigitalConverters,powersupplyandEthernetinterface.
TheReceiverUnitisasmallwall-mountedsteelcabinet withintegratedshockandvibrationabsorbers,designed forbulkheadmounting.Thenumberofcircuitboards willdependuponthechosentransducerconguration. TwistedpairEthernetisusedfordatacommunication withtheProcessingUnit.
TheReceiverUnitisnormallylocatedina"sonar room"closetothetransducerarrays.

ProcessingUnitdescription

TheEM124ProcessingUnitisprovidedtoprocessthesignalstoandfromthe TransmitterandReceiverUnits.
TheEM124ProcessingUnitisanindustrial computerusingbothCOTS(commercialoff-the-shelf) componentsandcustommadecomponents.Theunitis designedandtestedforruggeduse.
TheProcessingUnitperformsthereceiverbeamforming,bottomdetection,andmotion andsoundspeedcorrections.Itcontainsallinterfacesfortime-criticalexternalsensors suchasvesselattitude(roll,pitch,headingandheave),vesselpositionandexternal clock.Morethanonesensorofeachtypemaybeconnectedsimultaneously,withonein useandallofthemlogged.
TheProcessingUnitcontrolstheTransmitterandReceiverunitsviaEthernet communication,andisalsointerfacedtotheOperatorstationviaEthernet.
The48VoutputfromtheProcessingUnitcanbeusedforremoteon/offcontrolofthe TransmitterandReceiverUnits.
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TheProcessingUnitisnormallylocatedina"sonarroom"closetothetransducerarrays. Theunitcanalsobeplacedinthe"surveyroom"oronthebridge.

HydrographicWorkStationdescription

TheHydrographicWorkStationistheoperatorstationfortheEM124.
Adedicatedmaritimecomputerisprovidedwiththe EM124MultibeamEchoSounder.Itissetupwith allnecessarysoftware.
TheHydrographicWorkStationisbasedonthe Microsoft
TheHydrographicWorkStationisnormallymounted neartheoperatorworkspace.
®
Windows10operatingsystem.
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KongsbergEM124InstallationManual

Supportinformation

ShouldyouneedtechnicalsupportforyourEM124youmustcontactaKongsberg Maritimeofce.Alistofallourofcesisprovidedonourwebsite.Youcanalsocontact ourmainsupportofceinNorway.
A24hourtelephonesupportservicemayalsobeavailabledependingofthelevelof SLA(ServiceLevelAgreement).
•Companyname:KongsbergMaritimeAS
•Address:Strandpromenaden50,3190Horten,Norway
•Website:https://www.km.kongsberg.com
•E-mailaddress:km.hydrographic.support@kongsberg.com
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Preparations

Topics
Tools,equipmentandconsumablesrequiredforEM124installation,page17
Personnelqualications,page18
Preparations
Sonarroomrequirements,page19
Wheretoinstallthetransducer,page22
Acousticnoise,page27

Tools,equipmentandconsumablesrequired forEM124installation

InordertodotheEM124installation,allnecessarytoolsandequipmentformechanical work,cabinetinstallationandelectricalwiringmustbeavailable.
Itisnotpracticaltoprovideadetailedlistofallnecessarytoolsandequipment.Y oumust beequippedwithastandardsetoftools.Thistoolsetmustcomprisethenormaltoolsfor electronicandelectromechanicaltasks.Thisincludesdifferentscrewdrivertypes,pliers, spanners,acablestripper,asolderingiron,etc.Eachtoolmustbeprovidedinvarious sizes.W erecommendthatalltoolsaredemagnetizedtoprotectyourequipment.
However,youmustmakesurethatthefollowingspecializedtoolsareavailable.
•Allnecessarytoolsandconsumablesrequiredforwelding
•Allnecessarytoolsandconsumablesrequiredforphysicalinstallationoftransducer
framesandtransducermodules
•Allnecessarytoolsandconsumablesrequiredforelectricalinstallations
•AnarticulatedjackorsimilararrangementcapableofliftingtheindividualEM124
units
•Torquewrench
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KongsbergEM124InstallationManual
Note
Ifyouneedspecicconsumables,orifspecialtoolsand/ortestinstrumentsarerequired, theseareidentiedintherelevantprocedure(s).
Personnelqualications
TheinstallationoftheEM124isademandingtask.Itisveryimportantthatthe personnelinvolvedintheinstallationtasksarecompetentandexperiencedcraftsmen.
Asaminimum,thefollowingcertiedcraftsmenmustbeavailable.
•ServiceengineerfromKongsbergMaritime
•Welders
•Electricians
Note
Thequalityoftheweldingiscriticaltothesafetyofthevessel.Weldingmustonlybe donebyacertiedwelder .
Ifapplicable,thenalinstallationweldsmustbeapprovedbythevessel’ snational registry,thecorrespondingmaritimeauthorityand/orclassicationsociety.Observethe relevantrulesandregulationsrelatedtowelding.
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Preparations

Sonarroomrequirements

Topics
Environmentalrequirements,page19
Sizeandaccessrequirements,page19
Requirementsforinsulation,heatingandventilation,page20
Requirementsforelectricalinstallations,cablesandcommunication,page20

Environmentalrequirements

TheEM124unitsmustbeinstalledinadryanddust-freeenvironment.Theunitsarenot fullyprotectedagainsthumidity,dustorwater.
Itisimportantthatthesonarroomiskeptdry.TheEM124unitsmustnotbeexposed toexcessivetemperatures,dust,moistureorhumidity.Suchconditionscancause corrosiveattacksandsubsequentfailurestotheelectroniccircuitry.Visitthesonarroom atregularintervalstochecktemperatureandhumidity,andtakethenecessaryactions iftheenvironmentalconditionsarepoor.
Avoidrunninglargepowercablestroughthesonarroom.
ObservetheenvironmentalspecicationsrelatedtotheEM124units.

Sizeandaccessrequirements

Awelldesignedsonarroomwithawellttedsizeandeasyaccessreducestheriskof corrosion,andsimpliesmaintenance.Thisincreasessystemreliability .
Thesonarroommustbelargeenoughtohouseallthesystemunits.Theroommust provideenoughspacetoallowefcientmaintenance.Y oumustbeabletokeepallthe cabinetdoorsfullyopenwithoutunduerestrictiontoyourmovements.
1Theroommustnotbeusedforanyotherheavymachinery.
2Theroommustnotbeunnecessarilyobstructedbygirders,pipesetc,whichmay
causeinstallationproblemsorimpedemaintenance.
3Thesonarroommustbeaccessibleunderallconditionsatseaorataberth.
4Alldoorsorhatchesmustbedesignedsothatthetoolsandequipmentcanbe
removedwithoutbeingdisassembled.
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Requirementsforinsulation,heatingandventilation

Thebulkheadsinthesonarroomshouldbeinsulatedandprovidedwithaninteriorwall tothedeck.Theroomshouldbeequippedwithheaterandconnectedtothevessel's ventilationsystem.
Heatingrequirements
Heatingisaneffectivemethodforreducinghumidity.Theheaterinthesonarroommust dimensionedtomaintaintheequipmentwithinitsenvironmentaltolerances.
ObservetheenvironmentalspecicationsrelatedtotheEM124units.
Ventilationrequirements
Thesonarroomshouldbeconnectedtothevessel'sventilationsystemtoensureasupply ofcoolingair.Ifaventilationsystemisnotavailable,installtwo3”pipesfromthesonar roomtoasuitablefreshairlocationondeck.
Thefreshairshouldentertheroomasclosetotheooraspossible,andshouldbe extractedfromashighaspossible.Afunnelshapeddrip-collectormustbemounted belowtheventpipestodivertmoisturetothebilge.Onthemaindeck,thebest ventilationisprovidedwhentheoutletpipeisatleastfourmetershigherthantheinlet pipe.T okeepoutseawater,rainandspray,theventilationpipesmustbettedwith goosenecksoranequivalentdesign.
Note
Ifthevesselislikelytooperateintropicalconditions,asuitableairconditioningsystem mustbeinstalled.Theairconditioningsystemmustbeabletoprovideanambient temperaturethatdoesnotexceedthemaximumoperatingtemperaturesoftheEM124 unitsthatareinstalledintheroom.

Requirementsforelectricalinstallations,cablesand communication

Theelectricalinstallationsinthesonarroommustmeetminimumrequirementsto providesuitablelightsandsupplypower.
Lightrequirements
Thesonarroommustbeequippedwithsuitablelightingtosimplifytheinstallation andtoaidfuturemaintenance.
Communicationrequirements
Thesonarroomshouldbeequippedwithatelephone,anintercomsystem,oranyother meansoforalcommunicationbetweenthesonarroomandthebridgeand/orcontrol room(s).
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Powerrequirements
Eachunitinthesonarroomshouldbeprovidedwithaseparatecircuitbreakeronthe mainssupply.
Propervesselgroundmustbeprovided.
Aminimumnumberofadditionalelectricaloutletsmustbeprovidedforotherequipment.
Cablingrequirements
ThesonarroomunitsareconnectedtootherEM124unitslocatedindifferent compartmentsonthevessel.Theunitsmayalsobeconnectedtoperipheraldevices.If thesecablespassthroughhatchesorareaswheretheymaybedamaged,theymustbe runinconduits.Minimum2”conduitisrecommended.
Makesurethatallsystemcablesareproperlyconnectedandsecured,andinstalled withsomeslack.Theslackisessentialtowithstandvibrations,andtofacilitatefuture maintenanceandreplacements.
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Wheretoinstallthetransducer

Topics
Introductiontotransducerlocation,page22
Mountthetransducerdeep,page22
Avoidprotrudingobjectsnearthetransducer,page23
Keepthetransducerfarawayfromthepropellers,page24
Mountthetransduceratasafedistancefrombowthruster(s),page24
Summaryandgeneralrecommendations,page24

Introductiontotransducerlocation

Asingleanswertothequestion"wheretoinstallthetransducer"cannotbegiven.
Thephysicallocationofthetransducerdependsonthevessel'sdesignandconstruction, howthehullisshaped,andhowthewaterrunsalongthehull.Therearehowevera numberofimportantguidelines,andsomeoftheseareevenconicting.
Note
Theinformationheremustbeconsideredasgeneraladvice.EachEM124installation mustbehandledseparatelydependingonthehulldesignandtheotherelectricaland mechanicalsystemsinstalledonthevessel.

Mountthetransducerdeep

InordertoachievethebestpossibleEM124performance,mountthetransduceras deepaspossibleunderthevessel’shull.
Thereareseveralreasonsforthisrecommendation.
Flownoise
Considerthesituationswhenthevesselisunloaded,andpitchinginheavyseas.The vesselisridinghigh,andthebowmayevenbeliftedoutofthewater.Thiswillcausea lotofairtofollowtheshapeofthehull.
Theupperwaterlayersoftheseacontainamyriadofsmallairbubblescreatedbythe breakingwaves.Inheavyseastheupper5to10metresmaybelledwithair,andthe highestconcentrationswillbenearthesurface.Airbubblesabsorbandreectthesound energy,andtheymayinworstcasesblockthesoundtransmissionaltogether.
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Cavitation
Cavitationistheformationofsmallairbubblesclosetothetransducerface.Thebubbles appearbecausethelocalpressurebecomesnegativeduringpartsoftheacousticpressure cycles.Thecavitationthresholdincreaseswiththehydrostaticpressure.Thenoiseis madewhenthebubblesimplode.
Transmittinginair
Thetransducermustneverbeliftedfreeofthewatersurface.Ifthetransduceris activatedwhenoutofthewateritmaybedamagedbeyondrepair.Mountingthe transduceratadeeppositiononthehullwillinnormallypreventthis.
Slamming
Slamminghappensifthevesselhullclimbsoutofthewaterinheavyseas.Theforceof thewaterwhenthehullfallsdownmaypushthetransducerup,andmaycausedamage bothtothetransducerandtoitsmounting.Thisisespeciallyimportantforlowfrequency Transducerswithlargefaces.Theeffectofslammingcanbereducedbymountingthe transducerasdeepaspossibleonthehull.
Note
KongsbergMaritimeAStakesnoresponsibilityforanydamagestothetransducer,the cableorthemountingarrangement,causedbyslamming.

Avoidprotrudingobjectsnearthetransducer

Objectsprotrudingfromthehullwillgenerateturbulenceandownoise.Thiswill reducetheEM124performance.
Protrudingobjectsmaybezincanodes,transducersoreventhevessel'skeel.Holesand pipeoutletsarealsoimportantnoisesources,aswellasroughsurfacescausedbybad welding.Eventracesofsealingcompound,sharpedges,boltsoremptyboltholeswill createnoise.Alltheseprotrudingobjectsmayactasresonantcavitiesamplifyingthe ownoiseatcertainfrequencies.
Donotplaceatransducerinthevicinityofprotrudingobjects,andespeciallynotclose behindthem.Makesurethatthesurfaceofthetransducerface,thehullplatingandputty aroundthetransducerisasevenandsmoothaspossible.Mountingscrewsorboltsmust notbeextrudingfromthetransducer,theinstallationhardwareorthehullplating.If necessary,grindandpolishallsurfaces.
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Keepthetransducerfarawayfromthepropellers

Thepropulsionpropellersisthedominantnoisesourceonmostvessels.Thenoise iseasilytransmittedthroughthewater.Thisnoisemayoftenreducetheoverall performanceofyourEM124.
Thetransducermustbeinstalledasfarawayfromthepropellersaspossible.Thebest positionsarethereforeontheforepartofthehull.Positionsoutsidethedirectlineof sightfromthepropellersarebest.
Onsmallvesselswerecommendmountingthetransduceronthatsideofthekeelwhere thepropellerbladesmoveupwards.Thisisbecausethepropellercavitationisweakest onthatside.Thecavitationstartswhenthewaterowsinthesamedirectionasthe propellerblades.Thisiswherethepropellerbladesmovedownwards.

Mountthetransduceratasafedistancefrombowthruster(s)

Bowthrusterpropellersareextremelynoisy.Whenyoudecidewheretoplacethe transducer,youmustconsiderthenoisecreatedbymostbowthrusters.
Wheninoperation,thenoiseandcavitationbubblescreatedbythethrustermaymake yourEM124MultibeamEchoSounderuseless,almostnomatterwherethetransduceris installed.Whenthebowthrustersarenotinoperation,thetunnelcreatesturbulence.If yourvesselispitching,thetunnelmaybelledwithairoraeratedwaterintheupper positionandreleasethisinthelowerposition.
Ingeneral,thetransducershouldthereforebeplacedwellawayfromthebowthruster(s).
However,thisisnotaninvariablerule.Certainthrusterdesigns-combinedwiththeir physicallocationsonthehull-maystillofferasuitablelocationforthetransducer,even closetothethruster.Ifyouareindoubt,consultanavalarchitect.

Summaryandgeneralrecommendations

Someoftheinstallationguidelinesprovidedfortransducerlocationmaybeconicting. Forthisreason,eachvesselmustbetreatedindividuallyinordertondthebest compromise.
Ingeneral,themostimportantfactoristoavoidairbubblesinfrontofthetransducer face.Forthisreason,therecommendedtransducerlocationisnormallyintheforepartof thehull,wellaheadofthenoisecreatedbythebowwave.
Themaximumdistancefromthebowisnormallyequaltoonethirdofthetotalwater linelengthofthehull.
Note
Mountingthetransducermorethan10–15metersfromthebowmaycauseproblems withtheturbulentow.
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ATransducer
BInclinationangle
CHulllengthatwaterline
Preparations
DMaximum1/3ofthehulllengthatwaterline(C)
Ifthevesselhullhasabulbousbow,thismaywellbeagoodtransducerlocation,but alsointhiscasetheowpatternoftheaeratedwatermustbetakenintoconsideration. Theforemostpartofthebulbisoftenagoodlocation.
AThruster
BTransducerlocation
Thisappliestothevesselinnormaltrimandspeed.
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Important
Thetransducermustnothaveanegativeinclinationanglecomparedtowaterow.
Donotplaceatransducerinthevicinityofprotrudingobjects,andespeciallynotclose behindthem.
Makesurethatthesurfaceoftheresultinginstallationisassmoothandstreamlinedas possible.
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Acousticnoise

Aswithanyotherhydroacousticsystems,thequalityoftheEM124echodataand presentationsaresubjecttounwantedacousticnoise.Theechoesfromanylargeand smalltargetmustbedetectedinsidethenoise.
Itisimportantthatwekeepthenoiselevelaslowaspossible.Theisnecessarytoobtain longrangeanddependableinterpretationsoftheechoes.Evenwiththeadvancednoise lteringofferedbytheEM124,wemustaddressthenoisechallenge.Thisisimportant duringtheplanningandpreparationsfortheEM124installation.
Topics
Contributingfactors,page27
Selfnoise,page28
Ambientnoise,page31
Preparations
Electricalselfnoise,page31
Somemeanstoreduceacousticnoise,page31

Contributingfactors

Severalfactorsarecontributingtotheperformanceofthehydroacousticequipment usedonboardavessel.
Factorscontributingtotheperformanceofthehydroacousticequipmentusedonboarda vesselare:
•Thequalityandpropertiesofthetransmittedsignal
•Thequalityofthereceivingsystem
•Theoperationalsettingsmadeduringoperation
•Thepropertiesofthetarget(s)
•Thesignal-to-noiseratio
Themajorityofthesefactorscanneitherbecontrollednorimprovedbymeans ofinstallationmethodsortransducerlocations.Thequalityandpropertiesofthe transmittingandreceivingsystemsarekeyfactorsduringourproductdevelopment,while ourenduserdocumentationaimstohelptheusertomaketherightltersettingsduring operation.Asforthetargetproperties,thereisnothinganyofuscandowiththose.
Thesignal-to-noiseratio,however,canbeimprovedbymakingthecorrectchoices duringinstallation.
Signal-to-noiseratio(oftenabbreviatedSNRorS/N)isameasureusedin scienceandengineeringthatcomparesthelevelofadesiredsignaltothelevelof backgroundnoise.Itisdenedastheratioofsignalpowertothenoisepower,often expressedindecibels.Aratiohigherthan1:1(greaterthan0dB)indicatesmore
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signalthannoise.WhileSNRiscommonlyquotedforelectricalsignals,itcan beappliedtoanyformofsignal[...].
http://en.wikipedia.org/wiki/Signal_to_noise_ratio(September2013)
Thesignalistheechothatwewanttoknowsomethingabout,whilethenoiseisany unwantedsignalsordisturbances.Theechomustbedetectedinthenoiseandthereforeit isnecessarytokeepthenoiselevelisaslowaspossibleinordertoobtainlongrange anddependableinterpretation.
Thenoisethatcontributestothesignaltonoiseratiomaybedividedintothefollowing typesofnoise:
•Selfnoise
•Ambientnoise
•Electricalnoise
•Reverberation
AThetransducercanpickupnoisefrom
•Biologicaldisturbances
•Interference
•Cavitation
•Propellernoise
•Flownoise
•Acousticnoisefromotherhydroacousticsystems
BThetransducercableislong,andmaypickupelectricnoisefromgenerators,
pumps,coolingsystemsandotherelectricorelectromechanicaldevices.
CThepreampliersareverysensitive,andtheycaneasilypickupelectricalnoise
frominternalandexternalpowersupplies.Thepreampliersarealsovulnerablefor analoguenoisecreatedbytheirownelectroniccircuitry .Digitalnoisecreatedby theconverterandprocessingcircuitrycanalsocreateproblems.
DConverterstransformtheanalogueechoestodigitalformat.
ESignalprocessingcircuitrycancreatedigitalnoise.

Selfnoise

Anyvesselequippedwithahydroacousticsystem(forexampleechosounderorsonar) willproducemoreorlessselfnoise.
Therearemanysourcesofsuchselfnoise.W ewillheregointosomedetailsinorderto analysethedifferentsourcesofselfnoiseonavesselandhowtheymayinuenceupon thenoiselevelofthehydroacousticinstruments.
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Preparations
Machinerynoise
Themaincontributortomachinerynoiseisusuallythemainengineonboardthevessel. Thecontributionfromauxiliarymachinerymay,however,beconsiderable,especiallyif itisinpoorshape.Themachinerynoisecanbetransmittedtothetransduceras:
•Structure-bornenoisethroughtheshipstructureandthetransducermountings
•Water-bornenoisethroughthehullintothewatertothetransducer
Electricalnoise
Modernvesselsarenormallyequippedwithalotofelectricinstrumentssuchas hydroacousticsystems,radars,navigationsystems,andcommunicationequipment. Anyelectricinstrumentsmayinsomecasescauseelectricalinterferenceandnoise. Internationalregulationsandcerticationsareusedtocontrolandreducethis,buteven thesearelimitediftheelectricalsystemsarepoorlyinstalledand/ormaintained.
Propellernoise
Propellernoiseisoftenthemainsourceofnoiseathighervesselspeeds.V ariablepitch propellersorfastmovingpropellersusuallymakemorenoisethanxedpropellersor slowmovingpropellers.
Propellernoiseisusuallywater-borne.Insomecases,however,shaftvibrationsor vibrationsinthehullnearthepropellermaybestructure-bornetothetransducer.Ifa propellerbladeisdamaged,thismayincreasethenoiseconsiderably.
Propellercavitationisaseveresourceofnoise."Singing"propellersmightbeasourceof noise,whichinterferesatdiscretefrequencies.Insomecasesstaticdischargefromthe rotatingpropellershaftmaybequitedisturbing.
Cavitation
Cavitationistheformationofsmallairbubbles closetothetransducerface.Thebubblesappear becausethelocalpressurebecomesnegative duringpartsoftheacousticpressurecycles. Thecavitationthresholdincreaseswiththe hydrostaticpressure.Thenoiseismadewhen thebubblesimplode.
Cavitationnoisemayappearnearextruding objectsathigherspeeds,butmoreoftenitis causedbythepropellers.Propellercavitationisaseveresourceofnoise.Thecavitation startswhenthewaterowsinthesamedirectionasthepropellerblades.Thisiswhere thepropellerbladesmovedownwards.
Insomecasesaresonantphenomenonissetupinaholenearthehull.Thissoundwill haveadiscretefrequency,whileallotherownoisewillhaveawidefrequencyspectrum.
(ImagefromU.S.Navyinthepublicdomain.)
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Flownoise
Theupperwaterlayersoftheseacontainamyriadofsmallairbubblescreatedbythe breakingwaves.Whenthehullmovesthroughwateritwillcauseadisturbance,andthis willgeneratefriction.Thefrictionzoneiscalledtheowboundarylayer.Theowin thisboundarylayermaybelaminarorturbulent.
•Thelaminarowisanicelyordered,parallelmovementofthewater.
•Theturbulentowisadisorderlyowpattern,fullofeddies.
ATurbulentow
BLaminarow
CAirbubbles
Airbubblesabsorbandreectthesoundenergy,andtheymayinworstcasesblockthe soundtransmissionaltogether.
Theboundarylayerincreasesinthicknesswhenitbecomesturbulent.Theboundary layeristhinintheforwardpartofthevesselhull,andincreasesasitmovesaft.The thicknessdependsonshipsspeedandontheroughnessofthehull.Allobjectssticking outfromthehull,ordentsinthehull,willdisturbtheowandwillincreasethethickness oftheboundarylayer.Whentheowspeedishigh,theturbulencecanbeviolentenough todestroytheintegrityofthewater.Smallvoidsorcavitiesinthewaterwilloccurand thisiscalledcavitation.
Rattlenoise
Rattlenoisemaybecausedbylooseobjectsinthevicinityofthetransducer,likexing bolts.Therattlemayalsocomefromlooseobjectsinsidethehull.
Interference
Interferencefromotherhydroacousticequipmentonboardthesamevesselmaybean annoyingsourceofdisturbance.Unlessthesamefrequencyisusedformorethanone pieceofequipmentonlythetransmittedpulsewillcontributetotheinterference.
Inphysics,interferenceisthephenomenoninwhichtwowavessuperposeeach othertoformaresultantwaveofgreaterorloweramplitude.Interferenceusually referstotheinteractionofwavesthatarecorrelatedorcoherentwitheachother, eitherbecausetheycomefromthesamesourceorbecausetheyhavethesameor
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