Arrow Shark X-Hydro - Page 9

Thele ssofyourhullthattouchesthewater,theles s dragandthehigherspeed.But
withtoolittlehullinthewater,theboatwillbecomelessstableandcou ldoverturn.If
thereistoomuchhull inthewatersothebow(iethefro nt)isrunninglow,thebo atis
saidtoberunning"wet".I ftheboatistoolightonthewaterwithonlyasmalllength
atthebackint hewater,itissaidtoberunning"loose".
Anglingthepropupwillliftt hefrontofyourboatgenerallyresultinginlesshullin
thewaterandfasterspeed.Anglingtheproptoohighthoughwillcauseinstabilityand
thepropmay"ventilate"orspinw ithoutgrippingbecauseit'stooclosetothesurface.
Anglingthepropdo wnwillliftthebackoftheboatandkeepmorehullinthewater
generallygivingmorestablerunningbutwithlessspeed.
Tryingdifferentpropangleswillfindtheonethatworksbestforyourboatin different
waterconditions. Tostartwith,runastr aightedgealongthebottomoftheboat
projectingouttheback,andsetthestrutdriveunitsothepropshaftisparallelwith
thestraightedge.
Whenadjustingthestrut,youmayneedtoalsoslightly changetheangleofthe
stuffingtube.Ifyoudoneedtos lightlyrebendthat,dosoverycarefu llywiththeflex
shaftinsidethetubetominimisethechanceofmakingtoosharpabend.
Step 7:TunedPipe Performance Tip
Tunedpipesboostenginepowerbyusingthepressurewavesgeneratedby exhaust
gasestoliterallypullmo refuelintothecylinder.However,toachievethis,itis
cr iticaltohavetherightlengt hfortheexhaustgasesast heytravelfrom theexhaust
flangetothe"belly"ofthet unedpipe(that'swherethepipeisatitswidestdiameter).
ForourbilletXP254Mengine,thisdistanceisbetween370and390mmwhichneeds
tobemeasuredalongthecentrelineoftheexhaustincludingtheheaderpipe,as
showninthediagram.Havingeitheralongerorshorterlengthwillreducethe
engine'sperfor mance.