Raymarine ALPHA - Page 72

T
erm
Meaning
TimeT oBurn(TTB)
Thetimeremainingduringracestartcountdown
beforetheboatneedstostartmovingtowardsthe
startlineatfullspeed.
TimetoTack
Timetotackisthedurationleftuntilyouneedto
tack.
T rueWind
Theactualwindflow;itisthewindflowyoufeel,on
thewater,whenstationary.Truewindiscalculated
fromApparentwinddatafromawindtransducer
andSTW(SpeedThroughWater)fromaspeed
transducer.
TrueWindAngle
(TWA)
Theangleofthewindoverwater,relativetoboat’s
bow,observedwhenstationary.
T rueWindDirection
(TWD)
Thedirectionofthewindrelativetonorth.Thisis
theactualdirectionthewindisblowing.
InadditiontoSTW,Headingisalsorequiredto
calculateTWD.
TrueWindSpeed
(TWS)
Thewindspeedobservedwhenstationary,onthe
water.TWSistheactualspeedthewindisblowing
overwater.
Upwind
Movingintheoppositedirectionfromwhichthe
windisblowing.
V
elocityMadeGood
(VMG)
Sailingtermrelatedtothecomponentofasail
vessel’svelocityvectorthatisinthedirectionof
truewind.
WindshiftTheamountofvariationinT rueWindDirection
(TWD)overtime.
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