Raymarine ALPHA - Appendix A Sailing Glossary

AppendixASailingglossary
Belowisalistofcommontermsandabbreviationsusedinsailing.
T
erm
Meaning
ApparentWind
Thewindflowobservedwheninmotion.Apparent
windisdifferentfromT
ruewindinthatittakes
intoaccountyourownmovement,i.e.:speedand
directionoftravel.Apparentwindistherawdata
thatisreportedbywindtransducers,whichcan
thenbeusedinconjunctionwithotherdatasources
tocalculateTruewind.
Supporteddata:
•NMEA2000:PGN130306
•NMEA0183:MWV
ApparentWind
Angle(A WA)
Thewindangleobservedwheninmotion.AWAisa
combinationofthetrueangleofthewindandthe
anglethatisfeltduetodirectionandspeedoftravel.
ApparentWind
Speed(AWS)
Thewindspeedobservedwheninmotion.AWSis
acombinationofthetruespeedofthewindandthe
speedyouaretravelling.
DistancetoT ackThetraveldistanceremaininguntilyouneedtotack.
DistancetoLineDistanceremainingtotheclosestpointalongthe
racestartline.
DownwindMovinginthedirectionthatthewindisblowing..
GroundWind
Direction(G
WD)
Thedirectionofthewindrelativetonorth,as
observedonland.Thisistheactualdirectionthe
windisblowing.
InadditiontoAWA,COGfromaGNSSreceiveris
alsorequiredtocalculateGWD.
GroundWindSpeed
(G WS)
Thewindspeedobservedwhenstationary,as
observedonland.GWSistheactualspeedthe
windisblowingoverland.
InadditiontoAWS,SOGfromaGNSSreceiveris
alsorequiredtocalculateGWS.
T
erm
Meaning
Header
Awindshiftwhichcausesyourboattoturnmore
downwind.
L
aylinesVectorlinesshowingthecoursetheboatwilltake
whensailingattheoptimumangletothewind,on
eithertack.
Leeway
Thedifferenceinanglebetweendesiredheading
andactualcourse,causedbysidewaysmovement
ofasailingboatduetothewind.
LiftAwindshiftwhichallowsyourboattoturnupwind
andclosertoyourdestination.
Linebias
Thedistanceadvantageconferredbycrossingthe
startlineatthefavoredend.oftheracestartline
.
Polartable
Aperformanceprofileforaboat,showingtheboat
speedachievableatvaryinganglestothewind,with
varyingwindspeed.Insailing,theVelocityMade
Good(VMG)principledemonstratesthattravelling
inastraightlineisnotalwaysthequickestroute,
andpolarsenableyoutooptimizeyourvessel's
performancetoitsbestadvantage,byimproving
theaccuracyoflaylinestodisplayhowfaryou
needtosailonacurrenttacktoreachatarget
waypointaftertacking,andtakingwindconditions
intoconsideration.
RSW(Raymarine
SmartWind)
TheRaymarineSmartWindtransducerseries.The
RSWseriesoftransducersincludeabuilt-inattitude
sensorwhichisusedtoprovidemoreaccurate
readingsthanstandardwindtransducers.
SailplanSailconfigurationrecommendationsbasedonwind
conditions.
SailingupwindSailingascloseaspossibletothewinddirection.
TackAcoursechangemadebyasailingvessel,by
turningitsheadingintoandthroughthewind.
TackingThezig-zagmanoeuvreasailingvesselmakes
whentravellingupwind.
Sailingglossary
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