Simrad 38-7 - INSTALLATION REV D User manual

Installation manual
Simrad 38-7
38 kHz single beam transducer
TECHNOLOGY FOR SUSTAINABLE FISHERIES
www.simrad.com

Simrad38-7
Installationmanual
Thisdocumentprovidesageneraldescriptionofhow
toinstalltheSimrad38-7Singlebeamtransducer.The
informationmustberegardedasgeneralguidelinesand
recommendationsonly.Theinstallationshipyardmust
designandmanufactureinstallationhardwaretotthe38-7
transduceroneachindividualvessel.
130003/D
16.11.2009

Documenthistory
Simraddocumentnumber:130003/ISBN-13:978-82-8066-111-1/Currentrevision:D
Rev.A—Firstversion.Commonfortransducers38–7andES38B.
Rev.B01.09.1991Updated.Commonfortransducers38–7andES38B.
Rev.C02.10.2009Improved.ValidonlyforSimrad38–7.
Rev.D16.11.2009Supportbardescriptionchanged,mustbeinstalled.Added
drawingSupportbar[206574]onpage39.
Copyright
©2009KongsbergMaritimeAS
TheinformationcontainedinthisdocumentremainsthesolepropertyofKongsbergMaritimeAS.Nopart
ofthisdocumentmaybecopiedorreproducedinanyformorbyanymeans,andtheinformationcontained
withinitisnottobecommunicatedtoathirdparty,withoutthepriorwrittenconsentofKongsberg
MaritimeAS.Thedocument,oranypartofit,maynotbetranslatedtoanyotherlanguagewithoutthe
writtenapprovalfromKongsbergMaritimeAS.
Disclaimer
KongsbergMaritimeASendeavourstoensurethatallinformationinthisdocumentiscorrectandfairly
stated,butdoesnotacceptliabilityforanyerrorsoromissions.
Warning
Theequipmenttowhichthismanualappliesmustonlybeusedforthepurposeforwhichit
wasdesigned.Improperuseormaintenancemaycausedamagetotheequipmentand/orinjury
topersonnel.Theusermustbefamiliarwiththecontentsoftheappropriatemanualsbefore
attemptingtoinstall,operateorworkontheequipment.
KongsbergMaritimeASdisclaimsanyresponsibilityfordamageorinjurycausedbyimproper
installation,useormaintenanceoftheequipment.
Support
Ifyourequiremaintenanceorrepair,contactyourlocaldealer.Youcanalsocontactususingthefollowing
address:[email protected].Ifyouneedinformationaboutourotherproducts,visitourwebsite.On
thewebsiteyouwillalsondalistofourdealersanddistributors.
Ko n g s b e r g M a r it im e A S
S t ra n d p r o m e n a d e n 5 0
P. O. Bo x 1 1 1
N- 3 1 9 1 H o r t e n , N o r w a y
S i m r a d
Te le p h o n e : + 4 7 3 3 0 3 4 0 0 0
Te le fa x : + 4 7 3 3 0 4 2 9 8 7
c o n t a c t @s im r a d . c o m
w w w . s i m r a d . c o m

Installationmanual
Tableofcontents
ABOUTTHISMANUAL.......................................................5
SIMRAD38-7....................................................................6
WHERETOMOUNTTHETRANSDUCER...............................7
HOWTOINSTALLTHETRANSDUCER..............................11
Transducerinstallationinblister............................................................................11
Usethemountingring.................................................................................11
Smoothsurfaceisimportant........................................................................11
Useahorizontalsupportbaronlargetransducers..........................................11
Example:Largecirculartransducer..............................................................12
Commonguidelines....................................................................................12
Toe-in........................................................................................................13
Physicallocation.........................................................................................13
Transducerinstallationinboxkeel.........................................................................14
Usethemountingring.................................................................................14
Smoothsurfaceisimportant........................................................................14
Useahorizontalsupportbaronlargetransducers..........................................15
Example:Boxkeelinstallation....................................................................15
Transducerushmountedinasteeltank...............................................................15
Usethemountingring.................................................................................16
Smoothsurfaceisimportant........................................................................16
Useahorizontalsupportbaronlargetransducers..........................................16
Waterlled.................................................................................................16
Example:Flushmountinginasteeltank......................................................17
Transducerwithacousticwindow..........................................................................17
Usethemountingring.................................................................................17
Smoothsurfaceisimportant........................................................................17
Example:Acousticwindow.........................................................................18
Transducermountedinsidethehull.......................................................................18
Usethemountingring.................................................................................19
Smoothsurfaceisimportant........................................................................19
Example:Mountinginsidethehull..............................................................19
Transducermountedonadropkeel.......................................................................20
Retractabletransducer............................................................................................21
STEELCONDUIT..............................................................22
TRANSDUCERHANDLINGANDMAINTENANCE................23
Rulesfortransducerhandling.................................................................................23
Approvedanti-foulingpaints..................................................................................24
Usingself-lockingtaps...........................................................................................24
130003/D3

Simrad38-7
IntroductiontoEmugeself-lockingthreads...................................................25
Drawingstandard........................................................................................26
Tapsandgauges..........................................................................................26
Self-locktapsprovidedbySimrad...............................................................27
Supplierandmanufacturer...........................................................................27
TRANSDUCERCABLESPLICING.......................................28
DRAWINGFILE...............................................................29
Echosounderconnections......................................................................................29
Splicingthetransducercable.......................................................................29
GeneralPurposeTransceiver(GPT)wiring...................................................30
GeneralPurposeTransceiver(GPT)transducerplugassembly.......................31
Outlinedimensionsandinstallationdrawings........................................................32
Outlinedimensions[074647].......................................................................33
Mountingring[074076]..............................................................................34
Recommendedarrangement[074544]..........................................................36
Mountingprocedure[088759].....................................................................38
Supportbar[206574]..................................................................................39
4130003/D

Aboutthismanual
ABOUTTHISMANUAL
Purpose
Thepurposeofthisinstallationmanualistoprovidethegeneric
descriptionsandillustrationsthatallowsyoutounderstandthe
basicprinciplesforechosoundertransducerinstallation.
Abouttheinformationprovidedinthisdocument
Theinformationinthisdocumentmustberegardedasgeneral
guidelinesandrecommendationsonly.Theinstallationshipyard
mustdesignandmanufactureinstallationhardwaretoteach
individualtransducerandvessel.
Approvalbymaritimeauthorities
Wheneverrequired,theinstallationshipyardmustalsohavethe
installationapprovedbytheapplicablemaritimeauthorities.
Additionalinformation
Foradditionaldetailedinformationaboutthetransducerto
beinstalled,refertothedocumentationprovidedwiththe
transducer.Drawingsanddescriptionscanalsobeobtainedfrom
http://www.simrad.com.
130003/D5

Simrad38-7
SIMRAD38-7
Thepurposeofthismanualistheprovidethebasicinformation
requiredtoinstalltheSimrad38-7Singlebeamtransducer.
Transduceranddocuments
•Simrad38–7:KSV-082776
•Datasheet:164017
•Drawings:
–Outlinedimensions:830–074647
–Mountingring:499–074076
–Steelblister:111–082733
–Mountingprocedure:820–088759
–Mountingarrangement:820–074544
Note
Althoughdrawingsareprovidedtoexplaintheinstallation
principles,theinstallationshipyardmustprovidethenal
drawingsrequiredtotthetransducertoeachindividual
vessel.Also,whenapplicable,theinstallationshipyardmust
havethedrawingsandinstallationapprovedbytheproper
maritimeauthorities.Thedrawingsspecicforthe38-7
transducerarelocatedintheDrawingleonpage29.
Technicalspecications
RefertotheSimrad38-7datasheet.Youcanreadand/or
downloadthedatasheetonhttp://www.simrad.com.
Additionalpartsprovidedforinstallation
ThefollowingitemscanbesuppliedbySimradtofacilitate
installation.Theitemsmustbeorderedseparately.
•Mountingring:499–074076
•Supportbeam:099–206575
•Steeltank:599–133807
•Arctictank:KSV-065087
•Transducercable(forextension):642-016604
6130003/D

Wheretomountthetransducer
WHERETOMOUNTTHETRANSDUCER
Asingleanswertothequestionwheretolocatethetransducer
cannotbegiven.Itdependsverymuchonthevessel’s
construction,howthehullisshapedandhowthewaterruns
alongthehull.Therearehoweveranumberofimportantguide
lines,andsomeoftheseareevenconicting.
Mountthetransducerdeep
Mountthetransduceratadeeppositiononthehull.Considerthe
situationswhenthevesselisunloaded,andwhenitispitching
inheavyseas.
Thereareseveralreasonsforthis.
1Theupperwaterlayersoftheseacontainamyriadofsmall
airbubblescreatedbythebreakingwaves.Inheavyseasthe
upper5to10metresmaybelledwithair,andthehighest
concentrationswillbenearthesurface.Airbubblesabsorb
andreectthesoundenergy,andtheymayinworstcases
blockthesoundtransmissionaltogether.
2Anotherreasontogodeepisthecavitationinfrontof
highpowertransducers.Cavitationistheformationof
smallbubblesinthewaterduetotheresultinglocal
pressurebecomingnegativeduringpartsoftheacoustic
pressurecycles.Thecavitationthresholdincreaseswiththe
hydrostaticpressure.
3Thetransducermustneverbeliftedfreeofthewatersurface.
Transmittingintoopenairmaydamagethetransducer
beyondrepair.Mountingthetransduceratadeepposition
onthehullpreventsthis.
4Ifthetransducerisliftedupfromthewaterduringheavy
seas,itmaybedamagedwhenthehullstrikesbackatthe
seasurface.Thisisespeciallyimportantforlowfrequency
transducerswithlargefaces.
Mountthetransducerawayfromprotruding
objectsonthehull
Objectsprotrudingfromthehull,suchaszincanodes,sonar
transducersoreventhevessel’skeel,generateturbulenceand
ownoise.Holesandpipeoutletsarealsoimportantnoise
sources.Theymayactasresonantcavitiesamplifyingtheow
noiseatcertainfrequencies.Donotplaceanechosounder
transducerinthevicinityofsuchobjects,andespeciallynot
closebehindthem.Forthesamereason,itisveryimportant
thatthehullareaaroundthetransducerfaceisassmoothand
levelaspossible.Eventracesofsealingcompound,sharpedges,
protrudingboltsorboltholeswithoutllingcompoundwill
createnoise.
130003/D7

Simrad38-7
Mountthetransducerattheforwardpartofthe
hulltominimisetheeffectsfromtheboundary
waterlayer
Whenthevesselforcesitswaythroughthesea,thefriction
betweenthehullandthewatercreatesaboundarylayer.The
thicknessoftheboundarylayerdependsuponvesselspeedand
theroughnessofthehull.Objectsprotrudingfromthehull,and
dentsinthehull,disturbtheowandincreasethethicknessof
theboundarylayer.Theowinthisboundarylayermaybe
laminarorturbulent.Alaminarowisanicelyordered,parallel
movementofthewater.Aturbulentowhasadisorderlypattern,
fullofeddies.Theboundarylayerincreasesinthicknesswhenthe
owgoesfromlaminartoturbulent.Thegurebelowillustrates
theboundarylayerofavesselmovingthroughthewater.
Figure1Boundarywaterlayer
ATurbulentow
BLaminarow
CAirbubblesinthewater
Furthermore,airbubblesintheseawaterarepresseddownbelow
thehullandmixedintotheboundarylayer.Theboundarylayer
isthinunderneaththeforwardpartofthevessel,andincreasesin
thicknessasitmovestowardsaft.Ifthesidesofthehullaresteep,
someoftheairbubblesintheboundarylayermayescapetothe
seasurfacealongthevesselsides.Itisourexperiencethatawide
andatbottom,witharisinganglelessthanaround13degrees,
ispronetogivingairproblemsforthetransducer.Inanycasea
transducerlocationintheforwardpartofthehullispreferredin
ordertominimisetheinuenceoftheboundarylayer.
8130003/D

Wheretomountthetransducer
Mountthetransducerfarawayfromthepropellers
Thepropulsionpropelleristhedominantnoisesourceonmost
shingvessels,researchvessels,merchantvesselsandpleasure
crafts.Thenoiseistransmittedthroughtheseawater.For
thisreason,thetransducershouldbeplacedfarawayfromthe
propeller,whichmeansontheforepartofthehull.Positions
outsidethedirectlineofsightfromthepropellerarefavourable.
Onsmallvesselswithshortdistancesitisadvisedtomountthe
transduceronthatsideofthekeelwherethepropellerblades
moveupwards,becausethepropellercavitationisstrongeston
theotherside.Thecavitationstartsmosteasilywhenthewater
owsinthesamedirectionasthepropellerblade,andthatisto
somedegreethecaseatthatsideofthekeelwherethepropeller
bladesmovedownwards.
Mountthetransducerfarawayfromthebow
thrusters
Bowthrusterpropellersareextremelynoisy.Wheninoperation,
thenoiseandcavitationbubblescreatedbythethrustermake
theechosounderuseless,almostnomatterwherethetransducer
isinstalled.Andwhennotinoperation,thetunnelcreates
turbulence,andifthevesselispitching,thetunnelmaybelled
withairoraeratedwaterintheupperpositionandreleasethisin
thelowerposition.Ingeneral,alltransducersmustbetherefore
placedwellawayfromthebowthruster.However,thisisnot
aninvariablerule.Certainthrusterdesignscombinedwithits
physicallocationonthehullmaystilloffersuitabletransducer
locationsnearthethruster.Ifyouareindoubt,consultanaval
architect.
Mountthetransducerwithaslightlyinclined
transducerface
Ideally,thetransducerfaceshouldbemountedinparallelwiththe
seasurfacewhenthevesselisinnormaltrim,asthiswillprovide
themostaccurateechoinformation.However,itisalsovery
importantthatthewaterowoverthetransducerfaceislaminar.
Inordertoensurelaminarow,thetransducerfacemaybetilted
slightlyupwardsinrelationtothewaterow.Thisallowsthe
owingwatertomeetthefacedirectly,andassureslaminarow.
Theinclinationanglemusthoweverbedeterminedcarefully.The
anglemustbesmallontransducerswithnarrowbeamangles.As
aruleofthumb,mounttransducerswithbeamanglessmaller
thansevendegreeswithminimuminclinationangle.Thesmaller
beamangleyourtransducerhas,thesmallertheinclinationangle
canbe.Ensurethatyoudonotmountthetransducerwitha
negativeinclinationangle.Thismaycauseturbulenceunderthe
transducerface,andreducedechosounderperformance.
130003/D9

Simrad38-7
Summaryandgeneralrecommendations
Someoftheaboveguidelinesareconicting,andeachcasehas
tobetreatedindividuallyinordertondthebestcompromise.
Generallythepropellernoiseisthedominantfactor,anda
recommendedtransducerlocationisintheforepartofthehull,
withmaximumdistancefromthebowequaltoonethirdofthe
totallengthofthehullatthewaterline.
Figure2Generalrecommendationfortransducerlocation
ATransducer
BInclinationangle
CHulllengthatwaterline
DMaximum1/3ofthehulllengthatwaterline(C)
Ifthevesselhullhasabulbousbow,thismaywellbeagood
transducerlocation,butalsoheremustbetakenintoconsideration
theowpatternoftheaeratedwater.Oftentheforemostpart
ofthebulbispreferable.
Figure3Recommendedlocationofthetransduceronabulbous
hull
AThruster
BTransducerlocation
10130003/D

Howtoinstallthetransducer
HOWTOINSTALLTHETRANSDUCER
Therearemanydifferentwaystomountthetransducer.Theseare
therecommendedmethodstomountastreamlinedandcircular
transducersunderthehullorinatowedbody.
Transducerinstallationinblister
Withatransducerwithcircularhousing,onerecommended
installationmethodisbyusingablister.Thetransducerblister
mustbedesignedandmanufacturedbytheinstallationshipyard
totthevessel’ssizeandhullshape.
Usethemountingring
Largecirculartransducersaredesignedtobemountedusing
amountingring.Asuitablemountingcanbeprovidedby
Simrad,drawingsarealsoavailableforlocalproduction.The
mountingringisweldedtotheholepreparedforthetransducer.
Boltsthroughthetransducerbodyintothemountingringwill
securethetransducerinplace.Notethatseveraltransducersuse
directionguidestoallowcorrectmounting.
Smoothsurfaceisimportant
Mountingscrewsorboltsmustnotbeextrudingfromthe
transducerortheareaimmediatelyaroundit.Makesurethatthe
surfaceofthetransducerface,theinstallationhardwareusedto
mountit,thehullplatingandtheputtyaroundthetransduceris
asevenandsmoothaspossible.Obstructionsonthesesurfaces
willcreateproblemswithturbulentow.
Useahorizontalsupportbaronlarge
transducers
Duetoitsphysicalsize,the38-7transducermustbettedwith
ahorizontalsupportbar.Thepurposeofthissupportbaristo
protectthetransducerfromdamageintheeventofslamming.
Thishappensifthevesselhullclimbsoutofthewaterinheavy
seas.Theforceofthewaterwhenthehullfallsdownmaypush
thetransducerupandcausedamagetoitsmounting.Thesupport
barcanbesecuredtothemountingringusingthreadedrods.See
Supportbar[206574]onpage39.[1]
1.Slammingistheimpactofthebottomstructureofashipontotheseasurface.Itismainlyobserved
whilesailinginwaves,whenthebowraisesfromthewaterandsubsequentlyimpactsonit.Slamming
inducesextremelyhighloadstoshipstructuresandistakenunderconsiderationwhendesigningships.
(Wikipedia)
130003/D11

Simrad38-7
Example:Largecirculartransducer
Theillustrationbelowshowsatypicaltransducerblisterdesigned
foralargetransducer.Notethatduetothephysicalsizeof
thetransducer,aU-shapedsupportbar(E)isusedtosupport
thetransducer.Thepurposeofthissupportistopreventthe
transducerfrombeingpushedupintotheblisterinheavyseas.
Figure4Largecirculartransducer
(CD017010A)
H
E
E
K
G
B
D
A
C
F
J
I
AStreamlinedblister
BStiffeningrib
CDrainageholes
DInclinationangle
EU-shapedsupportbar(recommended
onlargetransducers)
FForward
GCableserviceloop
HStufngtube
IMinimum400mm
JRoundedcorners
KAiroutlet
Commonguidelines
Thebestperformanceisobtainedwithablisterheightof40cm
ormore.Astreamlinedshapeandroundededgesreducetheow
noise.Averticalleadingedgeorfrontwillguidetheaerated
watertothesidesoftheblister.Theorientationoftheblister
shouldfollowthewaterow.
12130003/D

Howtoinstallthetransducer
Theinterioroftheblistermustbelledwithseawater.Use
drainageholesinthebottomandanairoutletonthetop.The
waterpressurebehindthetransducerwillthencompensatefor
theoutsidepressureduringvesselmovementsinroughsea.
Werecommendthatlargediametertransducersarettedwitha
horizontalU-shapedsupportbar.Thisbarcanthenbesecured
tothemountingringusingthreadedrods.
Thetransducercablepenetratesthehullinastufngtube.Leave
anadequateloopofthecablebehindthetransducerforeasy
mountingorremovalofthetransducer.
Toe-in
Theprimaryconsiderationmustbetoallowlaminarwaterow.
Inmostcasesthisisachievedbydesigningtheblisterinparallel
withthekeel.However,iftheblisterislocatedclosetothebow,
thefrontoftheblistermayhaveafewdegreestoe-intowards
thebow.
Figure5Toe-inprinciple
AKeel
BBlister
CToe-inangle
(CD17010C)
A
B
C
Theanglemustbechosentoallowformostefcientwaterow.
Itwillvarywiththelocationofthetransducer;thedepthbelow
thehull,thedistancefromthebow,andthedistancetothekeel.
Typicalanglesarefrom0to3°ondeplacementhulls.Onplaning
hulls,theangleisnormallycloseto0°.
Physicallocation
Theblisterisplacedononeofthesidesofthehull,andthe
distancefromthekeelisatradeoffbetweenaclosedistance
givingaturbulentowofwaterinanarrowpassage,andalarge
distancebringingthetransducerhigherupandalsomoreaffected
byvesselroll.Normallyadistanceofapproximately1misa
goodcompromise.
130003/D13

Simrad38-7
Observethehorizontalandverticaldistances(CandD)between
thekeelandthetransducerblister.Onamediumsizedvessel,the
horizontaldistance(C)shouldbeapproximately1meter.The
verticaldistance(D)mustingeneralbeassmallaspossible.This
isimportanttopreventthekeelfromshadowingthetransducer
beaminshallowwaters.
AKeel
BTransducer
blister
CHorizontal
distance
betweenkeel
andblister
DVertical
distance
betweenthe
blistersurface
andthekeel
Transducerinstallationinboxkeel
Vesselswithaboxkeelmayusethisfortransducerinstallation.
Theboxkeelisalreadythedeepestpartofthevessel.Ifthe
boxkeelistoonarrowtoaccommodatethetransducer,itcanbe
widened,eithersymmetricallyortoonesideonly.Inthelast
casetheinstallationcouldalsobedescribedasablistermerged
intothekeel.
Usethemountingring
Largecirculartransducersaredesignedtobemountedusing
amountingring.Asuitablemountingcanbeprovidedby
Simrad,drawingsarealsoavailableforlocalproduction.The
mountingringisweldedtotheholepreparedforthetransducer.
Boltsthroughthetransducerbodyintothemountingringwill
securethetransducerinplace.Notethatseveraltransducersuse
directionguidestoallowcorrectmounting.
Smoothsurfaceisimportant
Mountingscrewsorboltsmustnotbeextrudingfromthe
transducerortheareaimmediatelyaroundit.Makesurethatthe
surfaceofthetransducerface,theinstallationhardwareusedto
14130003/D

Howtoinstallthetransducer
mountit,thehullplatingandtheputtyaroundthetransduceris
asevenandsmoothaspossible.Obstructionsonthesesurfaces
willcreateproblemswithturbulentow.
Useahorizontalsupportbaronlarge
transducers
Duetoitsphysicalsize,the38-7transducermustbettedwith
ahorizontalsupportbar.Thepurposeofthissupportbaristo
protectthetransducerfromdamageintheeventofslamming.
Thishappensifthevesselhullclimbsoutofthewaterinheavy
seas.Theforceofthewaterwhenthehullfallsdownmaypush
thetransducerupandcausedamagetoitsmounting.Thesupport
barcanbesecuredtothemountingringusingthreadedrods.See
Supportbar[206574]onpage39.[2]
Example:Boxkeelinstallation
Thegurebelowillustratesasymmetricalboxkeelinstallation.
Figure6Boxkeelinstallation
ABoxkeel
BU-shaped
support
bar(only
recommended
onlarge
transducers)
CStufngtube
DCableinsteel
conduit
ECableservice
loop
(CD1701 1A)
A
B
D
C
E
Transducerushmountedinasteeltank
Flushmountingisusedonverylargevesselswithahullsodeep
thatnoairbubblesarefoundbelowthehull,andonvessels
operatinginshallowharboursorwaters,whereaprotruding
blistercannotbeaccepted.
2.Slammingistheimpactofthebottomstructureofashipontotheseasurface.Itismainlyobserved
whilesailinginwaves,whenthebowraisesfromthewaterandsubsequentlyimpactsonit.Slamming
inducesextremelyhighloadstoshipstructuresandistakenunderconsiderationwhendesigningships.
(Wikipedia)
130003/D15

Simrad38-7
Thestandardprocedureforushmountingonasteelvesselis
toweldasteeltankinsidethehull,andmountthetransducer
intothistank.
Usethemountingring
Largecirculartransducersaredesignedtobemountedusing
amountingring.Asuitablemountingcanbeprovidedby
Simrad,drawingsarealsoavailableforlocalproduction.The
mountingringisweldedtotheholepreparedforthetransducer.
Boltsthroughthetransducerbodyintothemountingringwill
securethetransducerinplace.Notethatseveraltransducersuse
directionguidestoallowcorrectmounting.
Smoothsurfaceisimportant
Mountingscrewsorboltsmustnotbeextrudingfromthe
transducerortheareaimmediatelyaroundit.Makesurethatthe
surfaceofthetransducerface,theinstallationhardwareusedto
mountit,thehullplatingandtheputtyaroundthetransduceris
asevenandsmoothaspossible.Obstructionsonthesesurfaces
willcreateproblemswithturbulentow.
Useahorizontalsupportbaronlarge
transducers
Duetoitsphysicalsize,the38-7transducermustbettedwith
ahorizontalsupportbar.Thepurposeofthissupportbaristo
protectthetransducerfromdamageintheeventofslamming.
Thishappensifthevesselhullclimbsoutofthewaterinheavy
seas.Theforceofthewaterwhenthehullfallsdownmaypush
thetransducerupandcausedamagetoitsmounting.Thesupport
barcanbesecuredtothemountingringusingthreadedrods.See
Supportbar[206574]onpage39.[3]
Waterlled
Asforablister,theinteriorofthetankmustbelledwithwater.
Thiscanbeaccomplishedbyairreleasethroughasteeltube,
whichisextendedeithertoopenair1.5mabovethewaterline
ortothewateroutsidethehullatapointhigherthanthetank
interior.
Ifthetubeisextendedtoopenair,drainagemustbeprovided
withleakageatthetransducerangeoraseparateholeinthe
tankbottom.
3.Slammingistheimpactofthebottomstructureofashipontotheseasurface.Itismainlyobserved
whilesailinginwaves,whenthebowraisesfromthewaterandsubsequentlyimpactsonit.Slamming
inducesextremelyhighloadstoshipstructuresandistakenunderconsiderationwhendesigningships.
(Wikipedia)
16130003/D

Howtoinstallthetransducer
Example:Flushmountinginasteeltank
Transducermountinginasteeltankisshowninthegurebelow.
Figure7Flushmountinginasteeltank
ASteeltank
BWater
CDrainagehole
DCableservice
loop
ESteeltubefor
airoutlet
FStufngtube
GCableinsteel
conduit
(CD17012A)
B
A
G
C
D
E
F
Transducerwithacousticwindow
Vesselsoperatinginarcticwatersneedspecialattentionon
transducerinstallation.Floatingblocksoficemaydamageeven
aushmountedtransducerface.ForthissituationSimradoffers
arctictanksindifferentsizes.
Usethemountingring
Largecirculartransducersaredesignedtobemountedusing
amountingring.Asuitablemountingcanbeprovidedby
Simrad,drawingsarealsoavailableforlocalproduction.The
mountingringisweldedtotheholepreparedforthetransducer.
Boltsthroughthetransducerbodyintothemountingringwill
securethetransducerinplace.Notethatseveraltransducersuse
directionguidestoallowcorrectmounting.
Smoothsurfaceisimportant
Mountingscrewsorboltsmustnotbeextrudingfromthe
transducerortheareaimmediatelyaroundit.Makesurethatthe
surfaceofthetransducerface,theinstallationhardwareusedto
mountit,thehullplatingandtheputtyaroundthetransduceris
asevenandsmoothaspossible.Obstructionsonthesesurfaces
willcreateproblemswithturbulentow.
130003/D17

Simrad38-7
Example:Acousticwindow
Thetransducershowninthegurebelowismountedinsidethe
tankbehindastrongacousticwindowwhichcouldbemadeof
polycarbonate.
Thetankislledwithoil.
Figure8Acousticwindow
ASteeltank
BOil
CAcoustic
window
DCableservice
loop
EStufngtube
FCableinsteel
conduit
GOilinlet
(CD017012B)
B
A
C
G
D
E
F
Transducermountedinsidethehull
Thetransducercanalsobemountedinsidethehull.
Aninstallationofthetransducerinsidethehull,andsounding
throughthehull,requiresagoodacousticcontactbetweenthe
transducerfaceandthehull.Buildatankaroundthetransducer
andllitwithaliquid.Oilusedinhydraulicsystemsisawell
suitedliquidforthispurpose.Itcontainsnogasbubblesand
isnon-corrosive.
Typicalvaluesofthetwowaylossare3dBforpolyester,6dB
foraluminiumand10dBforsteel.Hullsmadeofwoodora
sandwichtypewithfoaminthemiddle,attenuatethesoundso
muchthatthroughhullsoundingmustberegardedasimpossible.
Thelossvarieswiththedistancebetweentransducerfaceand
thehull.Thebestresultisobtainedwhenthedistanceishalfa
wavelength.ConsultSimradforadvice.Inadditiontotheloss,
thebeampatternisdegraded,becausealargerareaofthehullis
setintovibrations.
18130003/D