Your thoughts are similar to where I was 2 years ago. My flat panelled hull was aimed at easy building. I could not muster the will to carve another plug out of foam. I was prepared to give a little in performance with something easier to build.
I was very pleased and a little surprised when the end result actually performed better. So the flat panels was not a performance compromise. This was not quite what Michlet had predicted. The Flotilla software goes some way in providing the theoretical understanding of why it is better.
It would be reasonably simple to make a long slender lw hull for a proa using ply that has very good performance. AND likely better performance than could be achieved with a round section hull. It could be designed to trim flat or slightly bow up through a wide speed range.
If you want to have a go I can provide input on the shape that should perform best.
Rick
On 16/07/2010, at 2:21 PM, Doug Haines wrote:
--- On Fri, 16/7/10, tsstproa <bitme1234@yahoo.com> wrote:
From: tsstproa <bitme1234@yahoo.com>
Subject: [harryproa] Re: Rudder lift?
To: harryproa@yahoogroups.com.au
Date: Friday, 16 July, 2010, 13:25
What if the same 12m. hull was only 1/2 tonne displacement?
Todd
--- In harryproa@yahoogroups.com.au , Rick Willoughby <rickwill@...> wrote:
>
> The length constraint or non-constraint is a function of design speed
> and weight.
>
> As an example a 1 tonne hull with a flat bottom designed for minimum
> drag at 25 knots results in a length of 12m. However this hull will
> not generate enough bow up moment through wave making to counter the
> moment from the rig to drive it at that speed. Extending the length
> to 15m will get close.
>
Rick Willoughby
03 9796 2415
0419 104 821
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