Received: from hplms26.hpl.hp.com by opus.hpl.hp.com with ESMTP (1.37.109.18/15.5+ECS 3.3+HPL1.1) id AA085358265; Mon, 3 Mar 1997 11:44:26 -0800 Return-Path: <alain@paris.engr.sgi.com-DeleteThis> Received: from sgi.sgi.com (SGI.COM) by hplms26.hpl.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3+HPL1.1S) id AA154228265; Mon, 3 Mar 1997 11:44:25 -0800 Received: from cthulhu.engr.sgi.com (cthulhu.engr.sgi.com [192.26.80.2]) by sgi.sgi.com (950413.SGI.8.6.12/950213.SGI.AUTOCF) via ESMTP id LAA09549 for <@sgi.engr.sgi.com:wind_talk@opus.hpl.hp.com-DeleteThis>; Mon, 3 Mar 1997 11:40:26 -0800 Received: from paris.engr.sgi.com (paris.engr.sgi.com [198.29.108.113]) by cthulhu.engr.sgi.com (950413.SGI.8.6.12/960327.SGI.AUTOCF) via ESMTP id KAA21607 for <@cthulhu.engr.sgi.com:wind_talk@opus.hpl.hp.com-DeleteThis>; Mon, 3 Mar 1997 10:43:49 -0800 Received: (from alain@localhost) by paris.engr.sgi.com (950413.SGI.8.6.12/960327.SGI.AUTOCF) id KAA17149; Mon, 3 Mar 1997 10:43:49 -0800 Date: Mon, 3 Mar 1997 10:43:49 -0800 From: alain@paris.engr.sgi.com-DeleteThis (Alain Dumesny) Message-Id: <199703031843.KAA17149@paris.engr.sgi.com-DeleteThis> To: Multiple recipients of list <wind_talk@opus.hpl.hp.com-DeleteThis>, wind_talk@opus.hpl.hp.com-DeleteThis Subject: Re: Flat sails Reply-To: alain@sgi.com-DeleteThis
> From: <bo3b@apple.com-DeleteThis>
>
> His recommendation for overpowered is to partly flatten the sail to
> reduce the power, but still keep a curve. You don't want the full bodied
> curve, since you don't need that power, but you don't want it flat either.
>
> Then, the even better way to reduce power is to put on more downhaul, so
> the leech gets looser, even down to the boom, spilling more wind,
> handling stronger gusts, but keeping an airfoil.
>
I will also agree with that. Typically when I'm way overpowered, I will
downhaul FIRST to make the sail very loose (or get rid of the loose leach if
underpowered). Amazing how much more wind a modern sail with a lot of
downhaul will take. I use a FlipAndEasy which makes is pretty easy to adjust
and it also gives you a lot of leverage. I have to come off the water though.
After that, I add some outhaul to tension the sail again.
If I need to flatten the sail a little bit, I would do it at most 1/2 in, if
even that much (which I can do while in the water). Flat sails don't handle
more wind. Loose leach sails on the other hand can spill a lot of the gusts.
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Alain Dumesny |\ Silicon Graphics
alain@sgi.com-DeleteThis | \ Cosmo VRML Engineering
W - 415-933-5250 | o --- 2011 N. shoreline Bvld MS 982
Fax 415-933-0255 |-=|> ---- Mountain View, CA 94043
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