Lots of questions! My first boat design, again...

Discussion in 'Boat Design' started by garrick, Jan 30, 2009.

  1. garrick
    Joined: Mar 2008
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    Location: WI

    garrick Junior Member

    okay, for starters i've never designed or built a boat before, but i'm doing it. actually i tried designing one once before but never followed through with it. i wont be taking it out to sea or on the great lakes, just smaller lakes. its only going to be a little over 14', i'm not going to be using marine plywood, i will be using exterior plywood. this is somewhat of a budget boat, but i will be using epoxy resin with the fiberglass. The hull will be supported by plywood, however it will consist mostly of fiberglass.
    a couple questions...

    1. what type of fiberglass weave to use? biaxial, plain weave, twill? and what thickness/weight? about how many layers?

    2. I'm pretty sure i'm only going to use epoxy paint to waterproof the plywood because it will be completely surrounded by fiberglass anyways. good idea or bad idea? remember its budget and it doesn't have to last 100 years!

    3. what kind of plywood to use? needs to be strong, and as light as possible.
    i was thinking mahogany, or birch? also what thickness, i was thinking 3/8 for the deck and everything on top, was thinking some good 1" solid oak or something for the transom. any suggestions? i will probably be using cedar for alot of reinforcement because i have a bunch of laying around.




    this is the hull i will be using thanks to afrhydro. he said
    its got a 6 " flat pad and a 10 degree dead rise and the first set of chines are 26" from outside to outside
    the step is 10" deep and around 6" high the transom is 20" tall
    i would use okume ply wood or berch and clear fur for stringers

    what did he mean by all this, i don't know the terms. i know transom but that is it! what is the flat pad, dead rise, chines, stringeres? can somebody explain these dimensions for me?

    [​IMG]

    [​IMG]
     
  2. garrick
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    garrick Junior Member

    here is a basic design of what the boat will look like w/o the hull
    [​IMG]
     
  3. Fanie
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    Fanie Fanie

    Why don't you just buy an old fiberglass boat and redo that ? You can pick one up for quite cheap if you shop around some.

    Building a hull is not so easy, many things can go wrong there and it is a big big biiii-hi-hii-hi-hiiiiiiiiiiig job. Ask anyone.

    Are you building it because you like building boats, or are you building the boat to use it for recreation. If your answer is to use it, then shop around for that boat you can bring back to life.

    Look at looots of hull shapes, ask their owners how they respond on the water, will give you an idea what to expect with what type of hull.

    Also have a look at displacement hulls... some hidden advantages there most miss.

    Personally, I don't like using wood in boats.
     
  4. garrick
    Joined: Mar 2008
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    garrick Junior Member

    i don't have the money to buy a boat, but i do have alot of time on my hands, however i was also looking at something like this
    http://www.supremeboats.com/L48XP.html
    it was brought up in a thread earlier, if i could make a 14' version of this, it might work for what i want. i just want something to cruise around small lakes with. maybe pull a tube or a skier every now and then. It would be used mostly for fishing, and I want a large platform on front, will this type of boat take corners okay? not going to be real ruff with it but just wanted to know? maybe I can modify the hull just a little bit to fit my neads?
     
  5. Fanie
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    Fanie Fanie

    Any chance you could turn the time into a bit of money then ?

    I'm not trying to put you down, but the glass, resin etc is probably and most likely going to cost you more than buying a boat you can give a make-over.

    I have seen many many who started doing exactly what you want to do... then six months down the line they give up... the wife... the new car... the kids... and the window of opportunity passes you by.

    If I was you, I'd sniff around some. You may get a boat for less than you think if it's in someone's yard and in their way. Just make sure the hull is in good shape, no holes or cracks. They are out there.

    Let everyone you know know you are looking for a boat. You'll be surprised at what comes back at you. Three months of searching is better than a year or more's building and then give up losing it all.
     
  6. garrick
    Joined: Mar 2008
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    garrick Junior Member

    i don't see whats so hard or expensive about the jon boat, maybe 5 maybe 6 sheets of plywood tops, a couple gallons of resin, and obviously thats not everything but i could see it being done in under 500$ and a few weeks.
    even my first design should be able to be accomplished with under 1500, in a couple months, i don't need it to look show quality.
     
  7. PortTacker
    Joined: Nov 2008
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    Location: Oregon USA

    PortTacker Junior Member

    First let me say - go for it! You CAN do it!

    There are lots of tutorials online. And plenty of books.
    Look around at small boat building plans sites. Bateau.com and Selway-Fisher.com etc. (I think bateau has even a video you can buy.) Look at the pics, read the stuff, take note of the layup recommendations where published, see how planing boats are built way stronger (both the wood bits and the glass coverings) than rowboats - etc. You'll get the idea.
    You're right - a boat that small and simple in design will be easy enough to engineer and build, but it sounds like you need a wee bit more information before you start.

    You should be able to build a 14' jon boat for under $500. But the boat in your pictures is NOT a jon boat - it's much more complex and will require a bit of actual engineering unless you plan to keep the power small (say under 6hp)
     
  8. kerosene
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    kerosene Senior Member

    go for it if you have right reasons - however saving money is not likely to play out.
    You should make a detailed budget - count every piece of sandpaper and any tools you need to buy. It adds up really fast - proper plywood costs money, glass fiber costs money, a gallon of resin flies by quick too. And you quickly need more plywood than you would 1st assume. 5 sheets (4x8') doesn't make a very big boat.
     
  9. Fanie
    Joined: Oct 2007
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    Fanie Fanie

    Exactly what I would say. However, Garric, if you have no experience I would say go on some boats first, go fish a couple of times on a boat, look at hull shapes, visit a boat builder and work with glass a bit before you jump in the deep end... It may not be what you expected.

    If you make some errors your boat may result in tragedy.
     
  10. PortTacker
    Joined: Nov 2008
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    Location: Oregon USA

    PortTacker Junior Member

    One point that wasnt touched on enough - It appears from you say that your motivation is to save money.

    Trust me on this - You Can Not Build the boat you are describing for less than you can buy a similar used boat for. You just can't. (And that's even if you knew what you were doing, thereby eliminating much waste and also ending up with known good finished product, rather than hoping it turns out okay.) Look on eBay, Craigslist, newspaper, Nickel Ads, - there's dirt cheap derelicts everywhere.


    Build because you want to build, design your own when you know something about boats and boatbuilding - great fun! But not a money-saver.
     

  11. diwebb
    Joined: Jun 2008
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    Location: New Zealand

    diwebb Senior Member

    Hi,
    I agree with PortTacker wholeheartedly. Building your own boat is great fun and very rewarding, but does not save money. There are lots of derelict hulls about that can be resurrected quite economically. Your major expense will be the motor. To get anything like the performance you indicate you will need at least 25 HP and a reasonable runner of that horsepower will cost way more than the hull that you want to use.
    All the best with the project.
    David
     
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