[Rhodes22-list] Slot effect

[Steve Alm]

Bob,

When I'm pointing in light enough air so that I can use my entire 175%,  I
sheet in the genny as far as it will go--that is, the clew is touching the
sheet block and the block car is in its aftmost position.  Then I take the
traveler to weather and sheet in the main until the boom is right on the
centerline.  In other words, both sails are as close hauled as they can be.
I want to trust the engineering of the boat itself that this configuration
will create the perfect slot.  Yes?  No?  Maybe?  How do you know when it's
right?

Slim

On 3/2/05 1:50 PM, "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.
>> 
>> 
>> 
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> 
> 
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