CSC 30 Catamaran- the coastal passage

Discussion in 'Multihulls' started by peterchech, Nov 29, 2011.

  1. DGreenwood
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    DGreenwood Senior Member

    haiqu
    If you had any idea how absurd you sound to people that actually know this industry, you would be embarrassed. Seeing as you clearly don't know how much you don't know, and aren't about to listen to anyone, I guess we'll just have to be embarrassed for you.
    Have at it, show us how it's done. Engineer or not, you are more likely than not to end up with another abortion rotting away it the corner of a boat yard.
     
  2. CT249
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    CT249 Senior Member

    For a start, I think you'll find it takes eons more than a week to do a design. The reason I picked a week is that $1500 would only be a week's pay for a qualified person.

    Secondly, how many designers get to sell 100 versions of a design?

    Thirdly, if it was that easy why aren't good yacht designers all rich? The one I knew best was internationally famous, had about a dozen big boats in production and lots of expensive custom boats, but after decades of graft seemed to be poorer than he would have been if he had just stayed employed as an engineer.

    I think you'll find that all the contract details vary according to the individual contract between the designer and the person who obtained rights to the design. Normally buying one plan gives you the right to build one boat.


    There are other people who are much better qualified than I am to discuss this matter. However the question about beam attachments would seem to be a classic example of why designers need to be paid a reasonable sum. From my recollections about this sort of stuff and you know, it involves a lot of significant calculation on things like sheer forces, compression forces on the backing materials (if you're using simple bolts), compression and tension forces on the beam socket, fatigue life on the beam (not forgetting the influence of point loads and bolt holes etc), the way to avoid structural discontinuities around the attachment point etc.

    That involves hours of trying to work out the forces, looking up material data sheets, looking at other boats to see what has worked, working out why othe boats failed, yada yada yada.

    If you and I can't work all that out then why is it unreasonable to pay the people who CAN work it out a reasonable sum?
     
  3. CT249
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    CT249 Senior Member

    Nope, the facts are pretty clear and a breakdown by age and sex were included in the link, but since it's not really relevant let's leave it there. By the way, I quite clearly wrote that $1500 was "a bit over a week's pay for a typical Aussie". I did NOT say it was a week's pay.

    It's not a straw man argument to challenge someone to prove a claim. In this case, your claim is that designing a multi is so easy and fast that it's not worth $1500 - so prove it.

    If good structural design is so easy to identify why did you buy a boat that cracked?
     
  4. DGreenwood
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    DGreenwood Senior Member

    I had typed out a similar response to ElGringo but lost it in a crash.
    To add to 249s response, the best designers start out with a mechanical engineering degree, follow that up with a degree in nautical design from a place like Southampton, and have done a considerable number of sea miles on different designs. Then you have to have gathered a support system of other designers and engineers that have specialized knowledge in things like hydro and aerodynamics, composite engineering, metallurgy, propeller design, pumping systems, electrical controls, adhesives, the list goes on and on. Even a relatively small cruising boat, these days, is a very complex machine if you expect it function up to modern standards of comfort and safety. It is easy to underestimate the amount of skill and thought that goes into a good boat.
     
  5. ElGringo
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    ElGringo Senior Member

    CT249, you've got me wrong, I want to learn how to do it. But, there is not one book available that tells you how to attach a wood box beam to a catamaran hull. I can build the beams, I was just asking if the idea I had for attaching them would work. I was expecting an answer like "yes that will work" or maybe "no that is not a good idea because" I still tried to get an answer by sketching the boat as requested.

    On paying for a design, nobody has what I want. I am sure that several of the designs have hulls and beams that I could use, but they wont sell you part of a plan. If I hired them to design me the hulls and beams I'm sure they would open an existing design and say, "yep this one will work, that will be $1,500"

    There may be something magic about building a yacht or a ship but all I wanted was a simple answer.
     
  6. DGreenwood
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    DGreenwood Senior Member

    ElGringo...Yes the answer is simple if you have the skills to figure it out and are willing to cover the liability of drawing it for someone else. A simple attachment point like that can end a life or a whole family if it fails. The designer would have to know a considerable amount about the boat to effectively design that connection. A short list of things that might effect the choices would be the construction method used, the skill level of the builder, how much is weight of concern, the dimensions and weight of the boat, how and where will it be used, does it have to pass coast guard regs....I could keep going?
    Now this is not to say you are not perfectly capable of just building it and making damn sure you have enough meat there to cover all that is thrown at it, but if you carry that thinking all the way through the boat you end up with a slug. Maybe you don't care? maybe just look at construction methods in build photos of similar boats and copy them ?
     
  7. ElGringo
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    ElGringo Senior Member

    DGreenwood, yes I am sure I will overbuild it, and no it will never have to pass coast guard regulations.
    But, here is where I have a problem, you will find it in the rules for the forum.

    2.) Conduct must be conducive to sharing ideas and information

    Instead of sharing anything you get your intelligence questioned and a sales pitch from several designers suggesting you buy their design.

    All I wanted to know was would it work, yes or no.
     
  8. CT249
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    CT249 Senior Member

    EL G, where did anyone question your intelligence? I don't think anyone did, did they?

    There's a big difference between sharing information (as requested by the forum) and getting a professional to spend a few hours running the calculations they have developed over decades of experience and study to work out whether your design would work. It's not surprising there's no book on this subject. How many would it sell and how would the person qualified enough to write it ever make it worth their while to give away their knowledge?

    You've already got information from a few pros; isn't that a pretty good return for some very basic sketches that don't show things like beam bolt sizes, tolerances in the socket, the layup of the reinforcing around the socket etc? As a non-expert all I can see is a sketch that doesn't indicate whether the bolts are 3/16" or 3", and how the structural discontinuity around the corners of the socket will be handled. Given the lack of that sort of basic information, how could anyone say whether your design will work or whether it will fall apart? And what do you mean by "work"?? Do you mean whether it will "work" with careful handling on a calm lake and good maintenance for the next three years, or will it "work" while dropping off a 6' wave while heavily overloaded after 15 years of hard work and possible rot due to possible lack of ventilation and use of cheap ply? Do you want it to "work" as a rigid low maintenance unit or do you want it to "work" as something that needs to be rebuilt every few years and that will allow the hulls to slop around?
     
  9. ElGringo
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    ElGringo Senior Member

    CT249, you are absolutely correct and probably the smartest man in the whole world today. Please forgive me for bothering you. I'll know who to ask important stuff. Have a nice day.
     
  10. catsketcher
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    catsketcher Senior Member

    I think the only people who complain about buying plans are people who have not ever built a large boat. The cost of think time, extra time in the shed, wasted materials, errors , incorrect flotation and structural insecurity off shore all pale into huge insignificance when compared to saving a few thousand on plans, let alone think of the resale.
     
  11. CT249
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    CT249 Senior Member

    El G, there was simply no reason for you to get insulting. I made it clear I'm not a designer and was just passing along the sort of questions they ask about designs. I specifically said I couldn't work it out myself. I don't know how anyone could read someone who wrote "I can't work all that out" and then think they were claiming to be the smartest guy in the room.

    The whole point was that designing this sort of stuff takes a lot of hard earned knowledge and skill that the experts (and I specifically said I wasn't one of them) can't just pass all that knowledge to others easily and quickly.
     
  12. ElGringo
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    ElGringo Senior Member

    I was not looking for all their knowledge. I asked one question and was told that my sketch was "Child Like", that I needed to consult a Naval Engineer, submit more sketches, and Woods told me I would be better off buying his plans. I have told Woods several time over the last year or so that he did not have what I wanted but I do like his Skoota 28

    I can not see where I should consult an engineer or buy plans when I asked one question. And, to be fair to Woods he is not the only one who is quick to suggest that someone buy their plans. Maybe they are in the group who have not sold a hundred sets. I am quite sure that all the people I talked to could have answered yes or no without looking anything up. It was a basic question. If I had asked how to tie a knot I think they would have tried to tell me the boat would sink without new ropes

    And, I missed where you said you couldn't work it out. I apologize for that.
     
  13. Gus7119
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    Gus7119 Senior Member

    Wow go away for a while and it degenerates into a bun fight. Everyone needs to chill I reckon. This was a really helpful user friendly forum I come back and dam theres people tell others off others being rude for no reason its sad.
    You'll get the answers and help u need by people who work in the cat building industry by being cool.
    Any ELGRINGO. I'll have a look at the beam and see if I can be constructive at all Ive been doing alot of study of other builds and plans and had alot of input by some deaigners and builders whos cats I have been on or seen.

    Anyhowz hope it returns to a cool helpful forum and that the pros return cuase the input Ive had has been fantastic for my build.

    Cheers to all and Im already ony way with a collection of hardware and glass so please all the guys that assisted stand by pics and questions to come.
     
    Last edited: May 15, 2016
  14. Gus7119
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    Gus7119 Senior Member


  15. Gus7119
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    Gus7119 Senior Member

    Ok after speaking to about 12 suppliers and all Aust ply now made with marine glue the suppliers are suggesting they sell the cheapest stuff to boat builders as the glue is as good as marine and the poxy does a good job.
    Also I have spoken to a few people who have built with BB grabe ply after a user he said a mate had a good outcome with BB. And some are 5 to 9 yrs old and still in great codition and costs only $40 per sheet. So the budget conscious builder seems to be able to do ok with BB if resale not an issue.
    Dont shoot the messanger just what Ive found with all my investigation prior to build. But as anyone whos been here a while knows I yook a deep breath and slowed down to get it right.
    Cheers
     
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