Simrad ST90 - About the Hull Unit Installation; Mechanical Support Brackets

442703/B
127
Aboutthehullunitinstallation
ThehullunitprovidedwiththeST90isdesignedtolowerthetransducerdownbelowthe
ship’shullwhentheST90shallbeused.WhentheST90isswitchedoff,thetransducer
ishoistedforprotection.Thehullunitisalargeandcrucialpartofthesonarsystem.
Note
Duetoitsphysicalsizeandweight,andthefactthattheinstallationtrunkpenetrates
thevesselhull,itisveryimportantthatthehullunitisinstalledandsecuredproperly.
Thehullunitgantrymustbesecuredtothebulkheadbymeansofmechanicalsupport
brackets.Thedimensionsandstrengthofthesupportbracketsmustbeadequateto
preventvortexinducedvibration.ThisarequirementtoensurethesafetyoftheST90
andthevessel.
Thehullunitshallbemountedontopoftheinstallationtrunkatthebottomofthehull.
Theinstallationtrunkpenetratestheship’shull,andallowsthetransducertobelowered
intothesea.Thehullunitisnormallylocatedintheforwardpartofthevessel.
Asageneralrecommendation,thehullunitshallbeorientedwiththehoist/lowermotor
pointingaft
.IfthisorientationmakesitdifculttoaccesstheMotorControlUnit,the
hullunitmayberotatedduringitsinstallationtothemostsuitabledirection.
Relevantcranesandliftingequipmentmustbeavailable.Freeaccessthroughthehullor
thedecksontothetopoftheinstallationtrunkmustbeprovided.
Topics
Mechanicalsupportbrackets,page127
O-ring,page128
Designandinstallationdrawings,page129
Hullunitinstallationexample:T opview,page130
Hullunitinstallationexample:Sideview,page131
Hullunitinstallationexample:Sideview,page132
Mechanicalsupportbrackets
Duetoitsphysicalsizeandweight,andthefactthattheinstallationtrunkpenetratesthe
vesselhull,itisveryimportantthatthehullunitisinstalledandsecuredproperly.
Note
Thehullunitgantrymustbesecuredtothebulkheadbymeansofmechanicalsupport
brackets.Thedimensionsandstrengthofthesupportbracketsmustbeadequateto
preventvortexinducedvibration.ThisarequirementtoensurethesafetyoftheST90
andthevessel.
Installingthehullunit