Foil Optimist

Discussion in 'Boat Design' started by Manfred.pech, May 16, 2016.

  1. Skyak
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    Skyak Senior Member

    Doug, no reason to get emotional -I WANT to see foiling progress to good low price one designs but am just calling it as I see it.

    60 to $70K for the quant 23 is quite reasonable. Is that something you know or are estimating? I have not found price listed anywhere and that price would get press. What other boats has he done that retail under $100k?

    My comment about Hugh was about his financial involvement not engineering -he is a supplier (NA), not a principle. Of course Hugh is capable of the 14fter you suggest but Hugh works on what he is paid to work on. I have not and would not diminish his contribution to his designs -of course he is hands on. I am just saying that if you are looking for a 14fter foiling scow to Hughs design, first you have to find a builder to pay Hugh to start the project and as boats get smaller, margins get smaller.

    Waszp being designed to conform with Moth class brings strengths and weaknesses. The benefit of having an established class from day one is big. It is a challenging boat to sail but I don't think that will be a big negative. It will also be faster than boats that are easier to sail which will help.
     
  2. Skyak
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    Skyak Senior Member

    I found it! Quant 23 "starts at 60-65k euro excluding VAT" (VAT differs by country 20 to 27%)

    65000x1.23VATx1.12D/E=$89,500

    So you could buy a quant 23 for under $100k but I suspect most owners will pay more.
     
  3. OzFred
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    OzFred Senior Member

    How does a thread start with a 7' 9" "foiling" Opti and end up talking about a $100k+ 23' scow? Other than the "F" word and they're both sailing boats, they have nothing in common.
     
  4. Skyak
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    Skyak Senior Member

    The same way all threads become about the expensive foiling scow -the "D" poster.
     
  5. Doug Lord
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    Doug Lord Flight Ready

    -----
    Riiight.. I suppose that explains your posts 21,29,31,32 and 34?! How silly can you get.......
     
  6. Skyak
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    Skyak Senior Member

    Extremely silly! And I made the "D" comment in to poke some fun, but looking back it appears you did turn the conversation to the quant 23 at the top of page 2, post 16.
     
  7. OzFred
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    OzFred Senior Member

    Hasn't anyone looked at this seriously? Glass–covered wooden foils? No method of controlling height or AoA of the main foil? No method of adjusting rudder angle? Extremely short rudder "strut"? Extremely inefficient foil shapes? Winglets? Really?

    And best of all, no way to remove the main foil once the centreboard is inserted and the foil attached. Is it supposed to be attached and removed as part of rigging and de–rigging the boat?

    All lift from the rudder will be transmitted through the locking spring on the top pintle to the top gudgeon. There is no indication of how lift from the main foil is transmitted through the centreboard case.

    It's an April fools joke that missed it's deadline but was published anyway.

    [​IMG]
     
  8. projetdared
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    projetdared Junior Member

    HI guys, hi doug.

    Don't take it too seriously. I know phillipe and this project was just to show something fun during " la semaine affoilante" at Quiberon.

    Gurval
     
  9. Doug Lord
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    Doug Lord Flight Ready

    Optifoil

    Hi, Gurval! Have they done any testing yet? I gather that altitude control is by moving crew weight which seems like it has a good chance of working.
    Any more info would be appreciated!
     
  10. daiquiri
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    daiquiri Engineering and Design

    I disagree with that, Doug. It is extremely hard (I am struggling to not use the word "impossible") to control the dynamic stability of that configuration by moving the crew weight.

    Don't know if you have ever sailed an optimist... I did in my youngest days, and it goes like this - your legs are pushing upwards on the hiking straps, feet in mid-air. Your butt is pushing down hard on the gunwhale. You can only move your upper body and have neither the agility nor the extent of longitudinal body translation required to shift the CoG of the boat quickly enough to compensate its movements. You are left with controlling the pitch, yaw and roll of the foiling opti with the sail tension and rudder only - which is theoretically possible but I wan't to see it happen in the real life. ;)

    Cheers

    P.S. - If we are talking about fully flying the boat, of course. ;)
     
  11. Doug Lord
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    Doug Lord Flight Ready

    Optifoil

    Slavi, never sailed an Opti but spent a few years in a 9' Dyer Dhow(pix below). If you look at the foils on a kiteboard or foiling windsurfer the distance(footprint) between the main foil and aft foil(footprint) is half,or so, of the footprint of the Opti and if you watch the guys foiling there is very little detectable movement. In other words, the foil system on the Opti will lend itself even better to crew weight altitude control. And then there's the comment in one of the links above that weight-shifting was what the designers intended for altitude control....
     

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  12. projetdared
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    projetdared Junior Member

    Yes that's true, it's hard to have a good weight transfer on a optimist (same for the other boats) but it is possible. It's like every systems, if you just can have a small input on it but if it's enough for control, that works.
    At my humble optinion, the good way to do that is to use 2 foils (rudder and daggerboard) with positive angle of attack but a llitle bit more for the rudder.
    You can see on this video that the girl is behind the daggerboard.
    https://www.youtube.com/watch?v=SlhD6G_6Bxs
     
  13. daiquiri
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    daiquiri Engineering and Design

    I wouldn't use kite and windsurf boards for comparison because they are very different kind of animals, relatively easy to control due to the body-mass to board-mass ratio. Basically, the CoG of kitesurfer's body is pretty much the CoG of the board + windsurfer. Similar situation for the windsurfers.
    Furthermore, the apparent wind is very high (compared to the true wind), so the small true-wind perturbations are effectively damped by the high speed of the board.

    In case of an Opti, the boat's weight is comparable to the body weight of the kids sailing it, hence a longitudinal body movement 2X is necessary to shift the boat's weight by X (in percentage). With their feet hooked to the hiking straps, it is a very hard task - absolutely not comparable to kiteboards and windsurfers.
    Foiling speed is also necessarily lower in this case (just consider the weight and the anti-aerodynamic shape of an Opti boat), which means that any true-wind perturbance has a much bigger influence on the boat's dynamics. Hence a hypothetical foiling Optimist with that foil layout would likely require quite the oposite to what is available - quick and ample range of body movements, coordinated with an efficient sail and rudder control.

    But that's just my two cents worth. I've been wrong many times before, and might be wrong in this case too. Time will tell.

    Cheers
     
  14. Doug Lord
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    Doug Lord Flight Ready

    Optifoil

    I disagree because of the huge difference in footprint---and because the designer thinks it would work.....
     

  15. daiquiri
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    daiquiri Engineering and Design

    Anything can work in a very specific environment and under a fixed or narrow range of design conditions.
    Usable things have to work and be controllable in the off-design conditions too. ;)

    Cheers
     
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