Raymarine i70 - Speed Calibration

9.Selectthelocationthatyouwantdepth
measurementstobetakenfrom.
AfterselectiontheDepthOffsetpageisdisplayed.
IfyouhaveselectedWaterlineorKeelaDepth
Offsetmustbeapplied.
10.SelectOffset:.
11.UsetheUpandDownbuttonstoadjustthe
DepthOffsettotherequiredvalue.
Theoffsetvalueshouldbethesameasthe
measureddistance:
•fromthetransducerfacetotheWaterline,or
•fromthetransducerfacetothebottomofthe
Keel.
12.SelectSave.
SettinganincorrectDepthOffsetcouldleadtoyour
vesselrunningaground.
7.3Speedcalibration
Speedtransducercalibrationisrequiredas
transducerperformanceisaffectedbyanumberof
variablessuchastransducerlocation,shapeofthe
hullandwaterowcharacteristics.Thepurpose
ofperformingSpeedcalibrationistoensurethat
thespeedreadingsattheinstrumentareatrue
indicationofthevessel’sactualspeed.
Inordertoachieveaccurateresults,speed
calibrationmustbecarriedoutincalmconditions
withzerotideandzerocurrent.
Speedcalibrationalignstheinstrumentslogspeed
(SpeedThroughWater)to:
•SpeedOverGround(SOG),or
•areferencedspeed
CalibratingusingSOG
Formostinstallationsa1PointSpeedCalibrationis
allthatisrequired.
Ifthe1pointcalibrationdoesnotprovidesufciently
accuratereadingsoryourequireahigherlevelof
precisionforyourspeedreadingsthenaSpeedRun
Calibrationcanbecarriedout.Itisadvisabletocarry
outtheSpeedRunCalibrationatasmanyspeedsas
possible.Thisisparticularlyimportantforplaning
vessels.
*Conventionalspeedtransducershaveamaximum
of5calibrationspeeds,andsmarttransducers(e.g.
DST800)haveupto8.
Ifrequiredeachcalibrationpointcanalsohavea
calibrationfactorappliedtofurtheralignthelog
speedreadingacrossdifferentvesselspeeds.
Note:*TheSpeedRunCalibrationcannotbe
performedwhenthetransducerisconnectedto
aSpeedPod.
CalibratingwithoutSOG
Formostinstallationsa1PointSpeedCalibration
isallthatisrequired.Thecalibrationmustbe
performedusingawayofestimatingactualvessel
speedandadjustingthedisplayedreadingsothat
thelogspeedmatchestheyourestimatedspeed.
IfyoudonothaveSOGdataavailablethenthe
SpeedRunCalibrationcannotbeperformed.
Ifrequired,furthercalibrationpointscanbeadded
andacalibrationfactorcanbeappliedtofurther
alignthelogspeedwithactualvesselspeed.
iTC-5Smart(DST)Speedpod
SOG
No
SOG
SOG
No
SOG
SOG
No
SOG
1point
speed
calibration
Speedrun
calibration
Manual
calibration
Transducercalibration43