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 AA087888712; Mon, 3 Mar 1997 11:51:52 -0800 Return-Path: <bbense@shred.stanford.edu-DeleteThis> Received: from shred.stanford.edu by hplms26.hpl.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3+HPL1.1S) id AA156208712; Mon, 3 Mar 1997 11:51:52 -0800 Received: from localhost (bbense@localhost) by shred.stanford.edu (8.8.5/8.7.3) with SMTP id LAA27290 for <wind_talk@opus.hpl.hp.com-DeleteThis>; Mon, 3 Mar 1997 11:48:06 -0800 (PST) Date: Mon, 3 Mar 1997 11:48:06 -0800 (PST) From: "Booker C. Bense" <bbense@networking.stanford.edu-DeleteThis> To: Multiple recipients of list <wind_talk@opus.hpl.hp.com-DeleteThis> Subject: Re: Flat sails In-Reply-To: <199703030702.XAA05062@zonker.hpl.hp.com-DeleteThis> Message-Id: <Pine.OSF.3.95.970303113028.26922D-100000@shred.stanford.edu-DeleteThis> Content-Type: TEXT/PLAIN; charset=US-ASCII
On Sun, 2 Mar 1997, Ken Poulton wrote:
> > 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.
>
> This is certainly my experience. I find that I can usually handle
> higher winds by adding 1/2" to 1" of extra outhaul. Too much definately
> causes the sail to be harder to handle.
>
> I was reminded of this just a couple of weeks ago when my 5.4 was being
> overpowered (back-hand pull) in my usual setting, and found that 3/4" of
> extra outhaul (one boom notch) made the sail very hard to keep in trim.
> 3/8" extra was much easier to handle than the other two cases.
>
> I tend to downhaul maybe 1/4" extra when I am woriied about being
> overpowered, but I have not changed my downhaul in the middle of a
> session lately.
>
- If you have the right mast, downhaul makes a big difference. I
rarely if ever change the outhaul, but I am constantly tweaking the
downhaul. I even figured out how to do this while on the water. While
you're rigging on the shore, wiggle the base of the mast and watch how
the top of the sail flexs. One of the keys to sailing OP'd is to have
the top of the sail twist off during gusts. This effectively reduces
the sail area and makes the sail much easier to control. If your mast
is too stiff for the sail, it won't twist off properly and the sail
will be much harder to control. If the mast is too soft (pretty rare
these days), the top will twist off, but the mast will bend too much
and the draft pocket will move.
- The other key to sailing OP's is draft pocket stablity. This is why
you don't want to flatten the sail too much. You definately want your
camber inducer in on OP days. If the draft is not moving around,
you can control alot of power. Recent sails are designed with both
these requirements in mind and work best when you allow them to
flex and curve.
- Booker C. Bense : bbense@stanford.edu-DeleteThis
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