Subject: Re: [harryproa] Re: Rudders on lee hull only
From: "Rob Denney" <proa@iinet.net.au>
Date: 4/13/2007, 10:18 PM
To:
Reply-to:
harryproa@yahoogroups.com.au

G'day,
 
El is the test bed and it flies a hull.  So may the big ones, and if they do, steerage is critical.  The ratios for weight to windward vary, and you are right, it is not a major concern.  They work very well where they are, so at this stage I have not seen the need to experiment with athwartships location.
 
regards,
 
Rob
----- Original Message -----
From: Todd
To: harryproa@yahoogroups.com.au
Sent: Friday, April 13, 2007 1:03 PM
Subject: [harryproa] Re: Rudders on lee hull only



I was thinking your elementary was your test bed for the larger
boats. Which I thought were not designed to fly windward hull. What
are your ratio's for weight to windward I must be misunderstanding
your concept.

I was curious since the trimarans would normally load leeward float
along with main hull and have the main steering on the main hull yes
I know they do have smaller stearing blades on the floats. Since
your bigger boats don't fly windward hulls and have a similar load
to what the tri has, curious to find out if it would have same input
characteristics having main steering appendages on a shorter loaded
windward hull.

I'm finding out with the eql model that it is more weight sensitive
with weight placed on the windward hull than the leeward hull
meaning if I place enough weight to the rear on windward hull it
will fall off the wind bear away, but both hull and float are the
same length. I have to try with the board on the windward hull minus
weight.

Todd

--- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@...> wrote:
>
> G'day,
>
> No, for the following reasons;
> 1 They would lift out of the water if the hull flew
> 2) Their drag would increase weather helm. weather helm is not a
problem on harrys so this may not be a valid reason any more.
> 3) I don't like all the weight in the windward hull, except for
racing. Racing implies lifting the ww hull, see 1.
> 4) I have had enough trouble getting lee hull rudders to work
without starting on new sets of rudder problems.
>
> Despite all the above, the rudders on my Elementarry are getting
closer to amidships and I drew a Little America's Cup proa with
rudders and rig in the ww hull. Huge rm (lack of rm is a problem
with these boats) but prone to windward capsize unless the crew were
very good.
>
> We are about to launch a 6m proa with a pretty radical approach to
windward hull steering. Keep an eye on the web page for pics and
progress. If it works (pretty big if), it will change a lot of
preconceptions about proa steering.
>
> regards,
>
> Rob
>
>
> ----- Original Message -----
> From: Todd
> To: harryproa@yahoogroups.com.au
> Sent: Friday, April 13, 2007 12:28 AM
> Subject: [harryproa] Rudders on lee hull
>
>
> Rob, Have you ever experimented with just the rudders on the
windward
> hull?
>
> Or dagger board in center on leeward hull and rudders on ends of
> windward hull?
>
> Or any other configuration ?
>
> Todd
>
>
>
>
>
>
> ----------------------------------------------------------
-----------
>
>
> Internal Virus Database is out-of-date.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.18.18/734 - Release Date:
3/26/2007
>


Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.18.18/734 - Release Date: 3/26/2007

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