Installation manual

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.
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