Raymarine E90W - Page 141

3.SelectRadarAlarmsSetup.
4.SelectGuardZonesSensitivity.
5.Usetherotarycontrolortrackpadtoadjustthesensitivity.
MARPAoverview
MARPAisusedfortargettrackingandriskanalysisintheradar
application.
Withanaccurateheadingsensorconnectedtoyourmultifunction
display,youcanusetheMiniAutomaticRadarPlottingAid(MARPA)
functionsfortargettrackingandriskanalysis.MARPAimproves
collisionavoidancebycalculatinginformationfortrackedtargets,
andprovidescontinuous,accurate,andrapidsituationevaluation.
Thenumberoftargetsthatyoucantrackatanyonetimeis
dependentonthemodelofradarscannerthatyouareusing.
MARPAtracksacquiredtargets,andcalculatesthetarget’sspeed
andcourse.
Eachtargettrackedcanbedisplayedwithagraphicindicatingthe
ClosestPointofApproach(CPA),andTimetoClosestPointof
Approach(TCPA).Thecalculatedtargetdatacanalsobeshownon
yourscreen.Eachtargetiscontinuallyassessedandanaudible
alarmissoundedifatargetbecomesdangerous,orislost.
ForeffectiveMARPAoperation,yourmultifunctiondisplaymust
haveaccurateheadingandspeeddataforyourvessel.Thebetter
thequalityoftheheadingandspeeddata,thebetterMARPAwill
perform.Forthebestheadingdata,aRaymarineSMARTheading
sensororagyro-stabilizedautopilotisrequired.
InTrueMotionmode,SpeedOverGround(SOG)andCourseOver
Ground(COG)informationisrequiredtoshowtruetargetcourse
andspeed.
InRelativeMotionmode,headingandspeedinformationisrequired.
Safetynotices
MARPAcanimprovecollisionavoidancewhenusedwisely.Itis
yourresponsibilitytoexercisecommonprudenceandnavigational
judgement.
Thereareconditionswhereacquiringatargetmaybecomedifcult.
Thesesameconditionsmaybeafactorinsuccessfullytrackinga
target.Someoftheconditionsare:
•Thetargetechoisweak.Thetargetisveryclosetoland,buoys
orotherlargetargets.
•Thetargetoryourownvesselismakingrapidmanoeuvres.
•Choppyseastateconditionsexistandthetargetisburiedin
excessiveseaclutterorindeepswells.
•Choppyseastateconditionsexistyieldingpoorstability;own
vessel’sheadingdataisveryunstable.
•Inadequateheadingdata.
Symptomsofsuchconditionsinclude:
•targetacquisitionisdifcultandtheMARPAvectorsareunstable;
Usingradar
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