International Moth Design

Discussion in 'Boat Design' started by BigYeet, Feb 20, 2020.

  1. BigYeet
    Joined: Feb 2020
    Posts: 5
    Likes: 0, Points: 1
    Location: NZ

    BigYeet Junior Member

    BUTTERFLY pic 3.jpg BUTTERFLY picture.jpg BUTTERFLY pic 2.jpg Hey everyone! I'm designing a moth that I am planning to make. I just want everyones thoughts about the boat.
    Cheers
     
  2. wet feet
    Joined: Nov 2004
    Posts: 470
    Likes: 38, Points: 28, Legacy Rep: 124
    Location: East Anglia,England

    wet feet Senior Member

    I wish you well with the endeavour.What the original post doesn't say is whether you have spent any time sailing a Moth.If not,I suggest you get hold of one as soon as possible and get a couple of hundred hours of experience to build on.The rendering looks capably done but most of the Moths I have seen in the last few years had wings that were integrated with the rig and your appear to be a bit far aft to make much of a difference in this respect.The amount of wing that can be used to move weight around and adjust the balance of the boat looks rather minimal but you may have the technique to overcome this apparent short distance.More detail design appears to be needed in respect of the rudder gantry before building.
     
  3. BigYeet
    Joined: Feb 2020
    Posts: 5
    Likes: 0, Points: 1
    Location: NZ

    BigYeet Junior Member

    Thanks for you post, I haven't spent any time in a moth but I only just started high school and I will not be able to get a moth but I might be able to sail a freinds wazp.As for you suggestions for the wings, I will be attatching supports for the mast to the wing. Some wing bars are much smaller than mine and I think it is a good size.
     
  4. Richard Woods
    Joined: Jun 2006
    Posts: 2,197
    Likes: 149, Points: 63, Legacy Rep: 1244
    Location: UK, USA and Canada

    Richard Woods Woods Designs

    I have a friend who was your age a couple of years ago and he did something similar. Plywood shell carbon over. I helped him do sea trials with the foils before he fitted the rig. Very impressive to see it lift out at about 6 knots. Unfortunately he didn't get the wing/rig framing right and it broke when he dry tested the rig. So he never sailed it.

    I assume you are on the FB Moth groups. They are very active

    Yes try a Wazp, easier than a Moth. What do you normally sail?

    RW
     
  5. BigYeet
    Joined: Feb 2020
    Posts: 5
    Likes: 0, Points: 1
    Location: NZ

    BigYeet Junior Member

    It is very impresive for the boat to fly in 6 knots, its a shame about the frame breaking though. I have been looking at some of the different moth FB groups and I normaly sail a Starling (nz one man boat)
     
  6. wet feet
    Joined: Nov 2004
    Posts: 470
    Likes: 38, Points: 28, Legacy Rep: 124
    Location: East Anglia,England

    wet feet Senior Member

    A bit of time in a Wazsp will be a solid foundation for learning about sailing a foiler.Anything learned can be worked into the evolutions of the design,and there will be several.I'm sure Richard will confirm that the first version is rarely exactly the same as the version that actually gets built.
     
  7. Richard Woods
    Joined: Jun 2006
    Posts: 2,197
    Likes: 149, Points: 63, Legacy Rep: 1244
    Location: UK, USA and Canada

    Richard Woods Woods Designs

    Thats a really nice boat. I didn't see any sailing, just in the Auckland museum and club dinghy parks. Pity there are none in the UK. We have the Streaker etc instead. I used to race a low rider Moth. Now have a RS Aero, only a few in NZ at present

    RW
     
  8. BlueBell
    Joined: May 2017
    Posts: 984
    Likes: 137, Points: 43
    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Looks great.
    Lets see some more detail though.
     
  9. BigYeet
    Joined: Feb 2020
    Posts: 5
    Likes: 0, Points: 1
    Location: NZ

    BigYeet Junior Member

    Thank for the suggestions so far, I will definetly be adding some more detail. If anyone knows anything about wand setup/ mechanism and rudder angle changing system etc, please tell me.
    Thanks
     
  10. wet feet
    Joined: Nov 2004
    Posts: 470
    Likes: 38, Points: 28, Legacy Rep: 124
    Location: East Anglia,England

    wet feet Senior Member

    I have a few photos from previous London dinghy shows that may show a little of the general ways of going about creating the systems.In fact next weekend sees this year's dinghy show and I will be there with a camera.Sadly the number of interesting boats is declining and most of the space is occupied by the bigger manufacturers.I also have a feeling this year might be the last reasonably well attended dinghy show as before next year there will be a financial penalty for anybody driving anything other than an ultra low emission car within the North circular road.The same concern has been expressed by the model engineering fraternity who hold their annual show in the same place.

    This was from 2010 as far as I remember.You will be able to see the way in which the wings are integrated with the shrouds and how some of the rudder gantries are pivoted.I don't think the wand system is particularly clear but you may find enough information from other sources to fill in the gaps.
     

    Attached Files:

  11. Doug Halsey
    Joined: Feb 2007
    Posts: 399
    Likes: 104, Points: 53, Legacy Rep: 160
    Location: California, USA

    Doug Halsey Senior Member

    I think you could learn a lot just by looking at the photos of all the bits & pieces in the Mach2 webshop (& similar sites for the other types of Moths)
    Mach2 Shop https://www.kasail.com/mach2/product
     
  12. ziper1221
    Joined: May 2018
    Posts: 13
    Likes: 0, Points: 1
    Location: florida

    ziper1221 Junior Member

    The wingbar angle looks a bit low. When heeled to windward, the higher the wingbar is the more righting moment you will have, at the cost of more difficult boat handling. In addition to the shroud concerns raised by other posters, you will want to get your weight a little further forward, especially when sailing upwind. The gantry is adjustable for rudder aoa, but that is just to get in the right range. All the sailing adjustment happens in the tiller. There is a worm gear that pushes the whole rudder and tiller against the pin, fore and aft.
     
  13. BigYeet
    Joined: Feb 2020
    Posts: 5
    Likes: 0, Points: 1
    Location: NZ

    BigYeet Junior Member

    Thanks for your posts so far guys I will definitely be taking these into account. If anybody knows about good shapes for the foil struts and foils please tell me
    Thanks again!
     

  14. ziper1221
    Joined: May 2018
    Posts: 13
    Likes: 0, Points: 1
    Location: florida

    ziper1221 Junior Member

    NACA 63-412 is the old standard, but I'm sure it's well out of date by now. I don't know what sections Mach 2 or Maguire uses. I've been meaning to try out different sections with xfoil but I haven't gotten around to it yet
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.