Raymarine i70 - Speed Calibration

5.Selectthedevicethatthetransduceryouarecalibratingareconnectedto
.
Alistofavailabletransducerdataisdisplayed.
6.Select
Depth
(1)
.
Important:
(1)S
teponlyapplicabletoiTC-5.
7
.Select
DepthOffset.
8.SelectDepthFrom:.
Alistoftransduceroffsetsisdisplayed:
•W
aterline
•Keel
•Transducer(default)
9.Selectthelocationthatyouwantdepthmeasurementstobetakenfrom.
Afterselectionthedepthoffsetpageisdisplayed.IfyouhaveselectedWaterlineorKeelan
offsetmustbeapplied.
10.Select Offset:.
11.Usethe Upand Downbuttonstoadjustthedepthoffsettotherequiredvalue.
Theoffsetvalueshouldbethesameasthemeasureddistance:
•fromthetransducerfacetotheWaterline,or
•fromthetransducerfacetothebottomoftheKeel.
12.Select
Save.
Settinganincorrectdepthoffsetcouldleadtoyourvesselrunningaground.
4.3Speedcalibration
Speedtransducercalibrationisrequiredastransducerperformanceisaffectedbyanumberof
variablessuchastransducerlocation,shapeofthehullandwaterflowcharacteristics.Thepurpose
ofperformingSpeedcalibrationistoensurethatthespeedreadingsattheinstrumentareatrue
indicationofthevessel’
sactualspeed.
Inordertoachieveaccurateresults,speedcalibrationmustbecarriedoutincalmconditionswith
zerotideandzerocurrent.
Speedcalibrationalignstheinstrument’slogspeed(SpeedThroughWater)to:
•SpeedOverGround(SOG),or
•areferencedspeed
CalibratingusingSOG
Formostinstallationsa1PointSpeedCalibrationisallthatisrequired.
Ifthe1pointcalibrationdoesnotprovidesufficientlyaccuratereadingsoryourequireahigher
levelofprecisionforyourspeedreadingsthenaSpeedRunCalibrationcanbecarriedout.Itis
advisabletocarryouttheSpeedRunCalibrationatasmanyspeedsaspossible.Thisisparticularly
importantforplaningvessels.
(1)
Conventionalspeedtransducershaveamaximumof5calibrationspeeds,andsmarttransducers
(e.g.DST800)haveupto8.
Ifrequiredeachcalibrationpointcanalsohaveacalibrationfactorappliedtofurtheralignthelog
speedreadingacrossdifferentvesselspeeds.
Note:
(1)
TheSpeedRunCalibrationcannotbeperformedwhenthetransducerisconnectedtoaSpeed
P
od.
CalibratingwithoutSOG
Formostinstallationsa1P ointSpeedCalibrationisallthatisrequired.Thecalibrationmustbe
performedusingawayofestimatingactualvesselspeedandadjustingthedisplayedreadingsothat
thelogspeedmatchestheyourestimatedspeed.
T ransducercalibration25