Raymarine LIGHTHOUSE 4 - Page 59

•Maximumvesseldraft—thedistancefromthewaterlinetothelowest
pointofyourvessel’
shull/keel.
•Safetymargin—anadequateclearancebelowthehull/keeltoallowfor
draftvariationandchangesinwaterorbottomconditions.
1.W aterline
2.Maximumvesseldraft
3.Safetymargin
4.[Minimumsafedepth]
Minimumsafedepthcalculationguidance
Theinformationbelowisprovidedforguidanceonlyandisnotexhaustive.
Someinfluencingfactorscanbeuniquetocertainvesselsand/orareasof
waterandmaynotbelistedbelow.Y oushouldensureyouaccountforALL
factorsthatapplytoyourcurrentsituationwhenmakingcalculations.
Someofthefactorsthatcaninfluencehowmuchavesseldrawsareshown
below:
•Vesseldisplacement(weight)—Avessel’sdraftwillincreasewhenitis
fullyladenwhencomparedwithitsunladendisplacement.
•Watertype—Avessel’sdraftwillincreasebyapproximately2%to3%in
freshwatercomparedtoseawater.
Someofthefactorsthatshouldbetakenintoaccountwhencalculating
asafetymarginare:
•Vesselmaneuveringcharacteristics—Avessel’sdraftincreasesdue
tosquat,trim,roll,pitchandheave.
•Chartaccuracy—Theelectronicchartdepthmaynotbeaccurateorthe
truedepthmayhavechangedsincethelastsurvey.
•Weatherconditions—Highairpressure,andprevailingwindstrength
anddirectioncanaffectwaveheight.
Minimumsafeheight
Duringthestartupwizardyoucansetaminimumsafeheightforyourvessel.
Theminimumsafeheightcanalsobeaddedorchangedatanytimefromthe
[Boatdetails]settingmenu:[Homescreen>Settings>Boatdetails].
Asuitablevalueforminimumsafeheightcanbeestablishedbyidentifying
yourvessel’smaximumheightfromthewaterlineandaddingasafetymargin.
•Maximumvesselheight—thedistancefromthewaterlinetothehighest
pointofyourvessele.g.:topofthemast.
•Safetymargin—anadequateclearanceaboveyourmasttoallowfor
heightvariation.
1.Safetymargin
Gettingstarted
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