Laminate drawings and schedule for 52 ft coastal catamaran

Discussion in 'Multihulls' started by Ismotorsport, Mar 4, 2012.

  1. Alik
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    Alik Senior Member

    Ism, who is the designer of Your boat?
     
  2. Ismotorsport
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    Ismotorsport Junior Member

    [​IMG]
    [​IMG]

    Photos from previous build by same designer... 52 ft catamaran Looks like large unsupported panels without additional bulkheads?? They used 1 inch h80 but was heavier design..
     
  3. Alik
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    Alik Senior Member

    Structure looks substandard, to ISO12215. But maybe compliance was not required. Pls specify name/location of designer.
     
  4. Ismotorsport
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    Ismotorsport Junior Member

    I would guess that since most of the designs are custom, there is no compliance standards, but I could be mistaken?
    The thing is that other designs have sailed Ocean legs without issue such as one whose photos you see. I specified a lighter simpler build, just got stuck holding the bag without detailed laminate drawings and such. Interviewing some NA's or rather they are interviewing me..:)
     
  5. gdoug
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    gdoug GD

    I don't think creating a lam schedule for this should be such a big ordeal.
    The hulls are large and extremely buoyant. You're expecting a load of 22,000 pounds. That means that these hulls are not very load sensitive. You also plan on using this as a cruiser not racing correct? That means the hulls will not be subject to overly strenuous loading conditions.
    For your case I would design a lam schedule around cost, because a high tech elaborate lam schedule isn't going to gain you anything. Create a lam schedule with materials that are used often I.e: 1708, 1808, 24oz roving, 10 oz mat are relatively abundant.
    Do not use carbon. Carbon is not a great material for hull forms and is very expensive.
    Weight is not extremely important in high volume displacement hulls. Trim is.
    I recently ran power speed tests on a 33' "wave piercing" catamaran w/ twin electric thrusters. I tested it at 4300 lbs and again at 5300 lbs. The fastest speed runs were at the Higher weight. (keep in mind this was powered)
    2-300 lbs of added weight to your lam schedule won't hurt you with those hulls.
    Truth is you could give this to 4 naval architects and get 4 different lam schedules.
    If you're not trying to break a world record you don't need an overly exotic layup.
    Here's my base layup for you:
    20 mils Gelcoat
    (1) layer 1.5 oz mat
    (1) layer 1708
    (1) layer 1808
    3/4" 5 lb density core cell
    (1) layer 1708
    (1) layer 1808
    probably over kill and not exceptionally new school, but it would work. Its actually a very strong quality schedule.
    1708 & 1808 are good to use because one has strands woven 45 degrees to eachother and the other has strands woven 90 degrees to each other. When you use them together they can desperse a load in all directs. Mat is heavy but prevents gelcoat print through. It also is more puncture resistant and due to the chaotic arrangement of the fibers it does a good job of "confusing the load" for lack of a more technical term. It doesn't give forces a direct chanel to run down our inherent places for stress to propagate.

    That lam schedule would probably work, but I'm sure there are others out there who have better ones. My main point is that you have lots of options, but depending on what your boat is designed to do there is no gain in a super high tech/ expensive lam schedule.
    Most lam schedules are inherently overbuilt anyway and this is because composites are not fully understood. I hear a lot of "yah that will work" in this industry and I work in a very high-tech sector of it.
    Most failures occur due to part geometry that allows excess amounts of stress to propagate in isolated area's or to poor build quality. I would spend more time finding a builder who knows what he's doing than the best of the best naval architects.
    With all that said. You need to address certain areas of the hull with different materials. IE keels, transoms, structural bulkheads, mast supports. For that you need to give a drawing package to a naval architect. Or at least be extremely confident in your builders
    ability. If you're in Florida I know a couple good ones.
    I'm curious to see how this post is received. But it's not bad advice.
    The lam schedule you have as a base will probably be fine. If you got it from a naval architect with experience you're good. Truth is unless you're designing a Boeing for the production line laminates aren't an exact science. This industry doesn't have capital to invest in such research, process and simulations. A hand layup will by definition never be proven or acurately simulated because no two are the same. The harder part is understanding the geometry of the hull structure and figuring out where the high stress points are and how to dissipate them. A naval architect or good experienced builder should be able to do this you.
    Bottom line don't sweat the base lam schedule too much for this boat.
     
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  6. Alik
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    Alik Senior Member

    Good advice but major point is missing: laminate schedule will depend on unsupported panel size! No NA will give advice based on photos; panels need to be measured and structural calculations performed to verify if this schedule is OK or not; it might be increased/reduced in some areas.
     
  7. Alik
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    Alik Senior Member

  8. Ismotorsport
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    Ismotorsport Junior Member

    Partly what you see there is my frantic attempts to find a possible substitute as things were going downhill with original NA and I had a timeline to try and keep to... In addition I was not as well versed as to what the designer would actually provide me for the money I was spending. What I was eventually left with was a general laminate plan but no laminate drawings...plus the model with structure and hydro info already posted. Hence my being here acting as punching bag..:p I can take it though
     
  9. waikikin
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    waikikin Senior Member

    Copy & paste...Consulting work needed on design
    Send me an email if you would be interested in consulting on a design for a 52ft catamaran. Its in rhino and I need a NA to run it through hydro testingnand stability and figure out float lines based on layup schedule.

    Thanks
    Luke

    In green is "conjecture" (proposition that is unproven), I think Luke is being pretty strait forward in his inquiries, in asking for assistance & every job has a budget for $ & otherwise.
    All the best in your endeavours from Jeff
     
  10. Ismotorsport
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    Ismotorsport Junior Member

    Part of the frustration is that I feel the same as Gdoug, that any decent NA engineer could finish the project, but everyone seems to want to own their own design and not consult on a present one. Believe me, I am not expecting anything for free. I am proponent of FAIR WORK = FAIR PAY...
     
  11. Ismotorsport
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    Ismotorsport Junior Member

    Appreciate the comment Jeff,

    I wish I could get more solid advice and info from others than just being slammed. I am putting all the info on the table. While I wait to hire another interested NA I am gonna try and seek help here. It's slowly coming together but was arguably a true cluster *k for a while not knowing how much I would get for the money spent... (word of wisdom - don't write the check until the job is done) ...
     
  12. Alik
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    Alik Senior Member

    OK, but do You understand that asking a guy from the website (who has evidently no boats built to his designs) to contact You about engineering - isn't is a bit risky??
     
  13. Ismotorsport
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    Ismotorsport Junior Member

    Alik,
    I can assure you that I would have vetted anyone who was interested in helping. Like Gdoug mentions I would like to think anyone who is qualified to take on the project can perform the work. I have a composite engineer in the family who works for military that works on way more technical stuff... ( but i am not planning on sailing through the straighrs of middle east) lol. I rather find NA or engineer in the marine field.
    I just responded with blanket statement of what I thought I would need.
     

  14. gdoug
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    gdoug GD

    He's inquiring on a site called "boat design" about a boat design. What a lunatic.

    PS. Can't argue about the panel size comment.
     
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