4 Meter mono foiler project

Discussion in 'Sailboats' started by wind_apparent, Apr 27, 2008.

  1. wind_apparent
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    wind_apparent wind driven speed addict

    Sorry doug, still no dice, though surface piercing foils are within the rule as it lays right now. (as you know, extra beam is a double edged sword on these things, seeing as you need to beat the boom across the boat on tacks and gibes)
     
  2. foilman24
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    foilman24 Junior Member

  3. Doug Lord
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    Doug Lord Flight Ready

    What a damn shame! And what about all his "sponsors"-seems like that is real unfortunate.
     
  4. wind_apparent
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    wind_apparent wind driven speed addict

    Well Doug, It comes down to I'd rather sail/race than build right now. As for the trapfoilers future, I will gladly donate the tooling to you if you want it. As for the sponsors, I'll still be plastering them on the hull, As long as I'm showing people how to use their products, they could give a rats *** what I build. tell you the truth, most people thought it was a moth anyway.:D, bigger fish to fry right now. First off getting on the water by spring.
     
  5. Doug Lord
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    Doug Lord Flight Ready

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    I'm sad to see this end this way but I wish you the best of luck!
     
  6. Doug Lord
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    Doug Lord Flight Ready

  7. wind_apparent
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    wind_apparent wind driven speed addict

    The hull shell is 5kg, the deck is 1.25kg, and the foredeck is .25kg (approx for all). Still needs transom, frames, bulkhead, and case. It won't be the lightest build around, but it might be the widest..... also has some of the least freeboard out there, especially in the stern.
     
  8. CutOnce

    CutOnce Previous Member

    You've been reading too many canoe threads, hence your disregard for Jennifer Lopez sterns.

    Under 15 pounds isn't exactly heavy. I don't think the slight additional width is a bad thing - it may reduce the lumberjack log rolling balance pre-requisite somewhat and actually allow you to spend more time upright. Some of these "trends" that get accepted as best practices become standards without anyone questioning why they really are still done. I think a lot of the skinny development was done pre-foiling for weight and prismatic co-efficient optimization as a displacement hull, and moving those hulls to foilers was evolutionary.

    It will be interesting to see if your design proves to be competitive when foiling without the narrowest hull in the water. I think there is a lot more development to do in rig and wing aerodynamics, that will affect performance more than hull width at sub-foiling speed. The additional width should reduce the problems associated with tramp tube attachment and flex.

    --
    CutOnce
     
  9. Doug Lord
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    Doug Lord Flight Ready

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    Thanks. Interesting that Mirabauds new hull is a bit wide as well. The only question I see with it is how it will affect lite air take off. I doubt there will be any serious negative to it at all.
    I see you expect to be sailing by spring-hope it works out.
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    I found this quote from Bill Beaver very interesting when commenting on the tests of his Hungry Beaver design-which was tested at several displacements simulating the unloading of the hull as the foils began to work: "At the light displacement over half the wetted surface area is retained despite shedding 3/4 of the weight". I guess a wider hull might have a higher percentage of the total wetted surface retained as the hull is unloaded?
     
  10. wind_apparent
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    wind_apparent wind driven speed addict

    Obviously this hull wasn't designed to be an 11' moth, but I have always had interest in moths even as I was trying to do my own thing. I started messing with wider moth hull form idea's because of many of the points that have been brought up in the last few posts. at some point it dawned on me that the shapes and widths where starting to be very close to what my project hull would be if I cut it down to the moth rule. It then became apparent that I would never finish the Sr-71 project just based on the amount of time I have to work in the shop. The two idea's met and created the current concept. I had read Bills moth paper, and that wider hull blip always stuck in my head. I have also always thought moth hulls might be better with a bit more form stability, and wider is always better as far as wing support is concerned. I apparently wasn't the only one thinking of these things, because when the Lister Monstro came to light, I noticed a low freeboard, wider hull form and thought that I may be onto something. The current design is far from optimal, but I think is a good enough jumping off point to gain some pretty good intel. Should be a nice solid and stable boat to learn on and hopefully I will be able to pass it on as a good starter boat to someone else when it has served its purpose. (or maybe I'll still stick a 9.5sm rig and a trap on it and see what happens.)
     
  11. waynemarlow
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    waynemarlow Senior Member

    Um, I've always felt the wider the hull the better, one only has to look at the 49er to see wide fat almost oracle style shape hull shapes which in light air seem to simply glide along. The Moth seems to have gone ubber narrow which then poses a problem for the larger sailor. The sailboards have gone all flat and wide but with some almost tunnel hull shape. The sailboards seem the fastest to me ( try paddling a long sailboard and see how easy it glides ) and easiest form requiring least energy to move.

    Why then simply not take a 3.5 m sailboard, fit on some wings and foils and your hull is made. weights are not unsimilar
     
  12. Doug Lord
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    Doug Lord Flight Ready

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    I don't know ,Wayne. The Moth beats a 49er anytime the two race when the Moth can foil. The "skinny" theory is low wavemaking drag on the way up to foiling. The boats are foiling earlier now so the hull-whatever it is- is less of a problem. But a wider hull is likely to have higher wetted surface and wavemaking drag than a skinny hull and if that is combined with excess weight it could prove to be slow. A wide hull with an all up weight toward the light end of Moth sailing weights-say around 220lb- will probably not be too much of a problem.It will be interesting to see how this plays out-if it plays out......
     
  13. waynemarlow
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    waynemarlow Senior Member

    Wetted surface is influenced by the total of the combined weight of the jockey and boat, whether that is spread over a narrow hull form with greater depth or a wider hull with less depth in the water. The old nutmeg of a dolphin being long and sleek doesn't quite hold true as it is totally under the water, and yet the average flat bottomed barge is a ***** to push through the water until it starts to ride on the surface where it has one of the least resistive hull forms of all.

    The Moth just wants stability for the jockey to get on board and then a hull form that gets itself out of the water as fast as possible at lowest speed. I thought that is what wind surfing boards were good at. Its something that has pondered me for some years.

    Perhaps its time to have a more careful look, anybody have any data on drag resistantance of a displacement hull such as the Moth to that of a tunnel hulled windsurfing board.
     
  14. Doug Lord
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    Doug Lord Flight Ready

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    I think the lower the takeoff speed the better the wider hull sounds.
     

  15. waynemarlow
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    waynemarlow Senior Member

    Which then leads me onto my next query, does a semi planning hull ( ie a windsurfing style hull with an its bitsy teeny foil back and front ) that doesn't totally come out of the water, but semi planes and traps air under its tunnel hull form, have less drag than a fully foiling boat relying on total foil support. The Moths are no where near as fast as boards yet, perhaps a cross over between the two.

    One thing though it would be tough on structures and bodies as the slamming and skimming at 20 + knots is going to be something else.:p
     
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