Mini Transat 650

Discussion in 'Boat Design' started by Indefatigable, Jan 26, 2016.

  1. Indefatigable
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    Indefatigable New Member

    I am an 18 year old amateur naval architect. I have designed a Mini Transat and i am looking to get some insight on the design. Let me know what you guys think and make some suggestions on changes i should make. I am currently trying to figure out CFD testing and would aprreciate ome advice on getting the mesh from autoCAD, Inventor or Delftship into OpenFOAM. Any help and or feedback would be greatly appreciated.

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  2. John Perry
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    John Perry Senior Member

    I think you could do with comment from someone who has studied the rules of the MiniTransat and has an understanding of the special requirements of this kind of sailing, perhaps also someone who has taken part in the racing, so not me!

    But, a couple of minor comments - you seem to have drawn rather a lot of guard rail stanchions - not necessarily bad but it is all windage. It occurs to me that with only a fairly small change to the shape of the hydrofoils, as viewed from ahead/astern, they could be made to slide inwards to lie almost flush with the topsides when not required to be deployed. Is this a canting keel design?
  3. Doug Lord
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    Doug Lord Flight Ready

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  4. Indefatigable
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    Indefatigable New Member

    Thank you for the responses. Yes this is a canting keel design.I am working through the rule book trying to make it more legal. As for the stanchions are mandatory. The stabilizer foils are on the beam limit of 3 m and are fixed. i can foresee issues regarding beam with the canting keel perhaps. Originally i was aiming for a stabilizer foil system closer to the imoca 60 banque populaire design that would slide to leeward but realized quickly it would breach beam regulations for sure.
  5. Skyak
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    Skyak Senior Member

    I applaud your enthusiasm. You have chosen an extremely challenging design that I am not sure can be a success without the data/experience of prior boats and races. The mustach foil is bleeding edge technology that might not survive or be allowed in the time it takes you to develop and build. At this point it has only proven an advantage downwind. Cost and reliability are TBD. I have seen quite a bit of technical data in these forums. Most if not all in links posted by Doug pertaining to the Open 60 class on the foiling week TFW. There was one particular article that detailed all the foil angles and gross dimensions with a utube video.

    As for changes
    -your hull design is a wide planing design but you are showing Mustach Foils rather than the daggerboards appropriate for the hull. Either change the foils or narrow the hull to something appropriate for the MFs. As it stands your foils interfere with the hull flow and would not provide much lift or leeway resistance.

    -Your MFs need to curve down from the hull to get enough foil deep enough to generate lift. You state the uprights are at the rule limit, but just based on visual comparison to existing designs I think that the rule does not count the retracted foil on the opposite side in the max beam. You are studying the rules, you tell me.

    At this point I would advise you to develop a program to calculate the forces in three dimensions on the boat -'Free Body Diagram' in engineering speak. The way these MF boats were developed was to start with the FBD and link it into a velocity prediction program and compare it to prior state of the art. Then they ran the VPP/polars through the weather data from race history and found they had an advantage in probable weather conditions. The FBD is the key to success in this design. Start there. CFD is cool complicated stuff but you could screw around with it for years and do nothing to improve your boat. You need foil profiles? Go to aero/hydro board and just ask. What they give free is beyond what you would develop in a decade. One additional note -even after you develop the foil profile the layup is another major challenge -Specifically the stresses in the arc between the vertical and horizontal sections.

    -Your rig is another question mark. You have 3 spreaders on a skinny mast but you have the poles sticking out of the hull for a simply supported wing mast. Which kind of rig do you plan?

    So you are a young amateur trying his hand at a bleeding edge racer design, what end? Are you looking to just develop your skills? Do you intend this design to be built? Do you know this is a mid six figure $ minimum build? Minimum seven figure $ to do it to win and if the weather does not turn out to favor downwind your $1M boat will be at a disadvantage to conventional $100k boats? If you have any intent of building a 6.5 I suggest you go with conventional dagger boards for your first build. If the mustach foil is the entire point of your interest would you consider a smaller development platform? I have been thinking about doing a toy open 60 design around 3.5M length. For me, the greatest thing about foiling sailboats is that you don't have to build and maintain a large boat to get high speed.

  6. Indefatigable
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    Indefatigable New Member

    Thanks for the input

    Thanks for all the input. Im working on an updated model with some significant changes ill post it the updates in a week or so. I eventually plan on crowdfunding a prototype but that's further down the line and a lot more needs to be finalize before that can happen.
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