[Rhodes22-list] Slot effect

[brad haslett]

Bob,

This will be quick because I'm about to use the "slot
effect" to get this bad boy off the ground.  The
leading edge devices on a jet work just like the jib
and main.  Besides more wing/sail area, you do create
a venturi effect.  Bernoulli said when you accelerate
a fluid you decrease its pressure.  When air passes
between the main and jib, it is accelerated, creating
a more of a low pressure area than the two sails would
acting individually.  I'll let Roger give you the
math.  As a cruiser, not a racer, I think the order is
Ginny, Main, Beer.  If it turns into to much work then
its beer, ignition, diesel.

Brad
--- Bob Weber <ruba1811 at hotmail.com> wrote:

> Ed, I don't know about filling your mailbox but here
> goes.  Al Gore claims 
> to have invented the "slot effect" right before the
> internet to replace our 
> dependance on neuclear energy (could not resist). 
> If you don't care about 
> going fast, forget about it.  Racers are concerned
> about the slot effect 
> particulary when sailing to weather.  The slot they
> are talking about is the 
> area between the jib or genny and the back side of
> the main.  Wind comes off 
> the windward side of the headsail and is funnelled
> behind the main.  It is 
> sort of a "Venturi" effect which is supposed to
> increase wind speed over the 
> leeward side of the main causing more lift to the
> main.  Why you would care 
> about this comes in trimming the sails for maximum
> speed and pointing 
> ability.  After tacking on a close hauled course,
> the speedsters will have 
> the genny and main eased slightly to build boat
> speed and then start trimmng 
> in the sails for close hauled.  Fast boats call this
> shifting thru the 
> gears.  The slot effect dictates that you make your
> final adjustment to the 
> Genny prior to the main since it is effected by the
> air comming off the 
> genny.  Ok, it is not that exciting but if you ever
> find yourself crewing on 
> a racing boat you will understand the order of
> operations (genny then main) 
> in sail trim and the idea behind it.  Any more
> information will reveal my 
> ingornance and disdain for sailing fast so I will
> stop.
> 
> Bob
> 
> >From: "ed kroposki" <ekroposki at charter.net>
> >Reply-To: The Rhodes 22 mail list
> <rhodes22-list at rhodes22.org>
> >To: "'The Rhodes 22 mail list'"
> <rhodes22-list at rhodes22.org>
> >Subject: RE: [Rhodes22-list] Bob Weber's Challange
> >Date: Wed, 2 Mar 2005 14:22:03 -0500
> >
> >Bob:
> >
> >""You may now define 'Slot' effect."----are you
> serious?  It is one of my
> >favorite topics.  Don't get me started! It actually
> is a good sailing topic
> >since there still some debate on the "effect"
> despite wind tunnel 
> >technology
> >and the like.  Any Mainsail trimmers want to jump
> in?  Bob""
> >	Of course, I am serious, for several reasons. 
> Notwithstanding the
> >temperatures, in the last two weeks people have
> been bringing up sailing
> >topics.  Why not discuss a real topic?
> >	I will be off the list for about three weeks.  In
> the past month we
> >have had a couple of cabin fever snarling clashes
> on the list.  This topic
> >will get away from nuclear power, other sailboats,
> Hilary, etc., etc.
> >It would be nice to still find the list here at the
> end of the month when I
> >get back.
> >
> >Ed K
> >Greenville, SC, USA
> >Addendum:  Post a picture of a vang for the GBI
> IMF.
> >
> >
> >
> >__________________________________________________
> >Use Rhodes22-list at rhodes22.org, Help?
> www.rhodes22.org/list
> 
> 
> __________________________________________________
> Use Rhodes22-list at rhodes22.org, Help?
> www.rhodes22.org/list
> 



	
		
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