[Rhodes22-list] UPS and sail trim

[Bill Effros]

Mark,

Thanks for posting this information a second time for my benefit.  I 
just got to this (I keep the interesting stuff I don't have time to read 
put aside for when I have a little more time--I just got to this, after 
spending a lot of time on the Gentry site because you mentioned it in a 
subsequent post.)

At some point you must have realized I had never read the original, and 
you posted the information again.  Thank you.

With regard to the Gentry site--it is fascinating!  I will surely 
rearrange my tell tales this winter.  (My system was strictly "seat of 
the pants" -- I could see I was headed in the right direction, but I 
also knew I didn't know what to do next.)

I will test many of the concepts Gentry introduces using my current 
tell-tale system this summer.  But I almost can't wait to take the mast 
down to set up the new tell-tale system for next year.  One of the most 
important modifications I will make to the Gentry system is putting the 
tell-tales where they can be continuously seen from captain's chairs.  I 
find it is more important at this phase of my education to be able to 
continually monitor sail shape, than it is to strategically monitor sail 
shape in the aerodynamically most significant zones of the sail.

You and Arvel have given me a lot to work with.

Bill Effros

Mark Kaynor wrote:

>All,
>
>Just before we left Blacksburg for Deltaville I was just going through some
>back issues of Cruising World and came a cross a three articles in the May
>(I'm pretty sure it was May) issue regarding light wind sailing. They
>discuss code 0 sails like the Doyle UPS, and have some good downwind /
>lightwind techniques.
>
>In the same vein, this web site has been being discussed on the Tayana site
>and seems like it would be of benefit to any sailor who wants to learn how
>to better trim their sails: http://www.arvelgentry.com/index.html
>
>The fellow who posted the link included the following: 
>
>I've mentioned several times about the precision of sail trim and its ease
>in doing so.  
>The following URLs are the recently recompiled Arvel Gentry website that
>contain the 'seminal' articles of the aerodynamics of sails written by the
>penultimate sailor/aerodynamicist that radically changed the way that
>sailors interpret the flow, trim and other 'goodies' about sails.  Gentry
>was the one who 'de-bunked' the slot effect, and perhaps is the ONLY one who
>correctly explained the interaction of a staysail flown under a genoa.
>Gentry's articles 'revolutionized' the way sailors interpreted and set their
>sails, and in effect was the 'secret weapon' used by the American entries of
>the America's Cup boats .... you remember back when the US boats WON. 
>
>And 
>
>The articles on "Gentry Tufts"  (sail trim, better close winded, etc.) that
>appeared in Sail Magazine were the 'landmark'.  I got introduced to these
>articles (then top secret info) by several crew members of Americas Cup
>boats in the 70s-80s ..... and from then on I hardly ever got less than a
>second place when racing.  Gentry was the 'aero' consultant to the American
>ACup boats for about 15 years. Those AC boats weren't better than their
>competitors, they were 'sailed better' due to the Gentry Tufts, etc. 
>More importantly the 'tuft system' will allow you to keep sailing your
>Tayana when other boats are either turning on their engines ... or are
>heaving-to.  
>
>FYI, for those that are strictly non-technical the "Sail Trim Guide" by Don
>Guilette (a world class C30 racer) is a wonderful guide to sail trim and
>shaping. Don took the Gentry articles and boiled them down into *very*
>simple and easy to understand directions (without lengthy explanation) ....
>available from www.sailboatowners.com.  Don's guide will promote good sail
>draft location, proper amount of sail draft, as well as other important
>trim/shape considerations (twist, etc.) .   Well worth the few $$.   
>
>Mark Kaynor
>
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>  
>