How Much Weight Can the Boat Float?

Discussion in 'Education' started by yaasaay, Jul 6, 2011.

  1. Boston

    Boston Previous Member

    I explain this to my customers in my own biz regularly and am often met with a somewhat less than stellar response so while I am deeply sympathetic to the attempt Par I'm thinking some folks, myself included, need to learn just enough to be dangerous and then come to the realization that its a danger to others and not just themselves.

    designing anything as critical as a boat or a bridge or an airplane requires a system of checks and balances beginning with the educational process and following all the way through to the inspection process. Some might say the inspector is a pain in the *** but I say he's doing me a favor, I might have screwed the pooch and pooch might not survive it all that well.

    cheers
    B
     
  2. daiquiri
    Joined: May 2004
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    daiquiri Engineering and Design

    One question I've never bothered to ask:

    Yaasaay, what kind of boat you are trying to build?
     
  3. hoytedow
    Joined: Sep 2009
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    hoytedow Carbon Based Life Form

    Actually, Vulkyn might be a useful resource for this fellow. Not only has he been a good student on this forum , he is Egyptian Arab and able to bridge problems with language. :cool:

    First rule: Never build anything that is not a seaworthy craft.
     
  4. Frosty

    Frosty Previous Member

    There you go --thats a good start.

    An 8th grader could not build an 8 story building it would not even get to the second foor stage or design a plane that would crash at 20,000 feet because it wouldnt get off the floor. No disrespect just bad examples.

    Certificates do not drive the hands, that would be the brain.

    I don't know of another trade where certification is thought to be so necessary, I want to build a boat like the Indians did 400 years ago --Im sorry your not qualified".
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Frosty, the math questions are typical of an 8th grade education level. The math understanding to comprehend yacht design, is solid 12 grade level. So, if you've completed high school and didn't cheat your way through math class, you've all the tools necessary to preform the calculations necessary, to design a boat.

    You also mis-interpreted the aircraft and elevator analogy, which is one that suggests, that possably some education about what they are doing, is a wise thing when people's lives are on the line, in case you've screwed up somewhere. This particular poster has asked the most rudimentary questions (dozens), which tells me he hasn't a remote idea of what he's doing. Again this scares the crap out of me, considering someone is going to trust this design, farther from shore then they can swim back to. It's one thing to see a "development" in a persistent poster, of which we have several, but this guy keeps coming back with questions an 8th grader can supply. Maybe they don't have books or Google in his country.
     
  6. hoytedow
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    hoytedow Carbon Based Life Form

  7. daiquiri
    Joined: May 2004
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    daiquiri Engineering and Design

    Yaasaay, the fundamental question has remained unanswered:

    - what kind of boat you are trying to build?
     
  8. yaasaay
    Joined: May 2011
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    yaasaay Junior Member

    Firstly, PAR, you talk like who know what I did so far when you say ''you have no where near the elementary skill levels necessary to design anything, including a boat''
    Because I have really started with the boat and I hope to finish it after a few weeks


    Second things, I think the problems is physical not mathematical and I have shown you the skills but I stopped when I reach to the density

    I think you just read the title and ignore all of it



    I try with canoe and until now I have finished the hell like this picture

    I reach to this stage

    http://imageshack.us/photo/my-images/13/canoek.jpg/

    The rest only coat it by fiberglass
     
  9. daiquiri
    Joined: May 2004
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    daiquiri Engineering and Design

    You have to understand that the main fear here was that you were trying to build a bigger boat, perhaps a one for commercial use. That would be a really dangerous situation which has probably prevented many people here from helping you out.

    A canoe is ok, people have been and are building them all around the world without having too much of a knowledge in boat design.

    The displacement is pretty easy to calculate if you have a curve of sectional areas, which can be created by measuring and plotting (along the waterline length) the areas enlosed by every single underwater section of your canoe. It works, of course, if you have plans (drawings) for your canoe.

    If you don't, then you can use the Block Coefficient (Cb) I had mentioned in my first reply. For the shape of your canoe, I'd say that you can assume a Cb = 0.55 as a first (and probably a pretty close) approximation, and calculate the displaced volume as:
    V = Cb * Lwl * Bwl * T
    where:
    Lwl is the waterline length
    Bwl is the wl beam
    T is the draft.

    By the way, I also suggest you to read this excellent article by Eric Sponberg: http://www.sponbergyachtdesign.com/THE DESIGN RATIOS.pdf

    Cheers
     

  10. yaasaay
    Joined: May 2011
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    yaasaay Junior Member

    daiquiri thanks

    really this is the answer which I was waiting it and thank you for the book I will read it carefully
     
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