Dennis
As noted earlier I have found pilot scale often leads to the fastest and cheapest way of arriving at the desired end result.
Scaling from what you are planning now is probably not required. Part of the pilot exercise is to validate the design process. So you should consider what might be possible with a particular package. Basically start with a clean slate and set out what you want in a beach proa. For starters it will only need to cater for a narrow range of displacement. Ideally it can be transported with the hulls intact although you might have sliding or folding beams. You can probably power it much closer to its limits.
Unless you are using Rob's folding technique it is tough to beat ply in flat panels for speed and ease of construction. I do not experience any of the problems with hard chines that others observe. I think the observed turbulence is due to leeway and this should be avoided by using properly sized and trimmed rudders. You can simplify the shape tremendously without losing much performance. Long, narrow and light are the primary factors. The rest is window dressing if you are just testing. Ultimately you want to validate that you can predict with some precision how the boat will perform and test the merit of various ideas. It may be a different matter if you want to test the proposed method of construction with some form of strip planking but a lot more work.
Rick
On 05/08/2010, at 10:50 PM, Dennis Cox wrote:
OK... Todd and Rick with his human powered boats are having way too much fun and I can't wait for years before I get mine in the water. I am dieing to play with these bi-direction rudders that Rick and Todd are discussing. Having never seen a Proa in the flesh... it might be prudent for me to sail one before I spend years building the big one.So I want to build a reduced size one simply, cheaply, but mainly... quickly. I've reduced my DelftShip drawings a few times and find that somewhere between a third and half scale version will support two people in a beach cat size. I happen to still have the mast, boom and worn out sails of a Hobie 14 Turbo (Main and Jib).It is intended to be a test bed, so cosmetics and long life robustness are not necessary. I am looking to use 5mm Luan (because its cheap and available) and I'll epoxy and possibly glass over that. I would like to try to model the curvature of my lee hull if possible.Any suggestions on......bending or developing the wood?...converting my Hobie mast to free standing or staying into an adequate Proa rig?
Rick Willoughby
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