Lofting or something else?

Discussion in 'Boatbuilding' started by multiHen, Jul 16, 2012.

  1. multiHen
    Joined: Jul 2012
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    multiHen Junior Member

    Hello all,


    I have purchased the plans for the ECO75 power cat.


    http://ikarus342000.com/ECO75page.htm

    It seems to involve lofting. I have all kinds of bulding skills but have never built a boat. Is there any other way to build this boat other than learning how to loft? CAD printouts? Hire a lofter?

    If I must learn to loft then so be it, a guide on where to begin to learn would be very helpful.

    Here is a sample drawing of one of the bulkheads.

    http://ikarus342000.com/Sampledrawing.PDF

    Thanks!
     
  2. Corley
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    Corley epoxy coated

    It's not definitive guide on lofting but there is a chapter on lofting in the Gougeon Brothers on Boat Construction. I seem to be posting this link everywhere but it is a good reference.

    http://www.westsystem.com/ss/assets/HowTo-Publications/GougeonBook%20061205.pdf

    It looks like stringer/frame construction from the frame segment shown. The keelson looks to be a timber fitted over a frame as do the chine stringers I think they may actually be called chine logs (sorry not that familiar with the terminology on this build method). If this is the case you will probably have a plan page detailing the layout and dimensions of each of the frames over which the stringers are fastened and faired off and how they are arranged on the building frame or strongback. It doesn't look to me like lofting will be required if it is you will normally have a lines drawing with a table of offsets included in your planset.
     
  3. Ikarus34200
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    Ikarus34200 Junior Member

    Lofting

    In the construction manual of the ECO 75 is a complete lofting instruction.
    You would see how easy it is with such a simple hull cross section in contrast to a curved hull one.

    Regrads

    Bernd Kohler
    K-designs
     
  4. Milehog
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    Milehog Clever Quip

    I think you will enjoy lofting the boat. Watching a list of numbers become the fair, sweeping curves that define your boat is satisfying.
    Having had the opportunity to inspect the smaller Eco power cat leads me to believe you have chosen a good design. Keep us posted throughout the build.
     
  5. Milehog
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    Milehog Clever Quip

    Bernd, much of your web site isn't accessible on Internet Explorer. I discovered Google Chrome will work though. If this could be fixed possibly you'd get more traffic?

    The economy a power cat can achieve makes sense to me. There might be one in my future if my wife finds one that she likes as much as our mono hull. I prefer, and my wife insists on two engines. Either identical twins or a main and small auxillary.
    I'm aware Mueller's Eco power cat went from small, noisey twins to a larger, quieter 20 hp single. It almost looks like there would be room for two 15 or 20 hp engines on the ECO 75's transom. This would be better than hull mounted engines for slow speed operation using only one engine. I understand weight is the enemy.
    40 hp engine = 100-105 kg
    25 hp = 75-82 kg
    15-20 hp = 48-55 kg
    10 hp = 40-55 kg.
     
  6. multiHen
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    multiHen Junior Member

    Thank you, It seems you are right about the design. Very good link thanks again for helping me.


     
  7. multiHen
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    multiHen Junior Member

    Simple when your the designer ;) not so simple when its your first time looking at boat plans. I will use your method described in the manual I also want to learn about what I am doing in detail. Thanks Bernd. :D

     
  8. multiHen
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    multiHen Junior Member

    Yes it is broken it redirects to a 404 page not found if you hit the the stop button before the page fully loads you can keep it from dieing or like below just use google chrome.

     
  9. Milehog
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    Milehog Clever Quip

    multiHen, as this is your first boat build I'd strongly suggest you build a dinghy using similiar construction techniques as the Eco 75. I know you want to get started but in the long run it could save time, money and frustration.
    Again, keep us posted as I'm very interested in your boat.
     
  10. rwatson
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    rwatson Senior Member

    It appears not to be lofting, just laying out dimensions.

    Lofting is drawing a shape on flat materials using something like

    25, 12
    12, 11.5

    where the first column is usually width ( from a centreline) , the second column is usually height from a baseline.

    Those sample plans are just plain dimensions for you to transfer to the plywood etc.

    Milehog's suggestion is a great one. Doing a small project to get the hang of laying up larger things will end up saving you time overall.

    The other thing to consider is doing the measurements on cheap MDF, cutting the shape first, and making sure that it all fits together, then using the mdf moulds to transfer to expensive plywood.

    Often, it is possible to create patterns from cheap mdf, and then using a router with a special guide, you can use that one mdf mould to cut out several plywood parts really accurately without having to re-measure.
     
  11. multiHen
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    multiHen Junior Member

    Thanks for all the suggestions gentlemen. Much apreciated. : )
     
  12. Milehog
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    Milehog Clever Quip

    If you can't see yourself building a dinghy consider building a model of the ECO75 first.
     
  13. multiHen
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    multiHen Junior Member

    Slowly getting it, spending alot of time researching and reading. Will be cutting my first piece of wood in a few weeks I think.
     
  14. rwatson
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    rwatson Senior Member

    Well done. Getting it into your head is important.

    Don't be afraid to make some scale panels of thick cardboard to sticky tape together.

    You just divide the dimensions by the same amount ( eg 1 metre = 1 centimetre ), and see how it fits together.
     

  15. multiHen
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    multiHen Junior Member


    That would make it all kinds of easy :D


    Thank again everyone
     
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