Looking to Build a Boat

Discussion in 'Boat Design' started by chada, Sep 25, 2008.

  1. chada
    Joined: Sep 2008
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    Location: Florida

    chada Junior Member

    Ok I am new to this site. I have a couple of ideas that I am pondering on.

    I am looking to build a relatively cheap boat that would serve the purpose of back waters and creeks and small lakes and ponds.

    What I am looking at is a flats boat kinda.

    I have a 14.5 ft jon boat that has cracked ribs and I have taken it to the welders and it would cost in the neighborhood of about $600 to have all the ribs repaired.

    I like the design of the jon boat but would like a little more freeboard. Safety sake for my 7 year old daughter.

    Here is my idea and any comments are highly appreciated.

    Stitch and Glue versus using my jon boat as a jig.

    Flip jon boat over and doing epiglass construction on the outside of the hull and removing the epoxy skin and completing the inside.

    Does this sound do-able with in a 1k budget.

    I do have glassing experience and wood working experience.

    Would like to keep as much wood out of it as possible.

    Any ideas????

    Thanks Chad
     
  2. BHOFM
    Joined: Jun 2008
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    BHOFM Senior Member

    I not sure about cost or how it would work, but I would think
    about making a female mold of the boat you have, Plaster
    and chicken wire. Then you could just lay up a glass hull.
    It shouldn't be to hard to raise the sides a little?

    Some of the "real" boat designers will jump in in a little
    bit. I hope?

    What's the problem with wood? It is easy to use and cheap!
    With epoxy, it can last a long time!
     
  3. chada
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    chada Junior Member

    Not sure if I understand what you mean about a female mold from chicken wire and plaster.
    Are you refering to covering the outside with chicken wire and plaster and flipping
    it over and laying the glass on the inside of the mold.
     
  4. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    Thin aluminum sheet is a pain in the backside to weld... probably why your welder wants six hundred bucks to patch up the old jonboat.

    Your summary of what BHOFM suggests is accurate. You could do this by flipping the old jonboat upside down, cleaning it up as best you can, and waxing the hull up really well. (Try multiple heavy coats of a solid, not gel-like, flooring wax.) Make a female mould off that using a few layers of plaster and chicken wire, reinforce it with scrap wood, and pull it off. Once you clean up and wax the inside of the female mould, you could lay up a new hull in there.

    Or, much less work: Go to http://www.instantboats.com/boats.html , pick one you like (look at the sailboats too, you can always build them without the mast), and spend $30 or so to buy the plans. Harold "Dynamite" Payson will send you a set of Phil Bolger blueprints, meticulously detailed and carefully arranged so as to be really easy to build from. The simpler boats can be built from scratch in a matter of days if you already know some carpentry. And they're good boats, too.
     
  5. StuartN
    Joined: Aug 2008
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    StuartN New Member

    If it was me, I'd use wood

    Doing up a stitch'n'glue jonboat would be a fairly easy exercise. I just like the look and feel of wood. Plus, I think you'd be back on the water quicker than laying up a fiberglass hull.
     
  6. BHOFM
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    BHOFM Senior Member

    I have made small model boats like I was telling him how
    to do it, we used the fiberglass tape for wallboard instead
    of chicken wire. And we used spray pan coating instead of
    wax, like Pam! It worked well on a small scale.
     
  7. chada
    Joined: Sep 2008
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    chada Junior Member

    OKAY I HAVE AN IDEA. WATCH OUT THIS HURT COMING UP WITH THIS.

    I did what ever mans does.

    Went to Home Depot and Just walked around and pondered.

    What if I was to take the stitch and glue technique and apply it in this form.

    You generally use a jig on the stitch and glue tech. So if I was to flip the boat
    over and over lay it with a 1/8 marine plywood and then cover the entire
    outside with a 9oz Epiglass mixture and wait for it to cure and then flip it over and do the inside with the same.

    Do you think that it would be sturdy enough.

    Providing I ribbed and stringered the inside.

    Or I am trying to make something harder than it needs to be.

    Just asking.
     
  8. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    I think that would work fine - it would depend on how 'flat' the hull was. in other words, how easy it is to bend the plywood accurately around the existing hull. Since it is built of aluminium, I expect it would work well.

    However - I suspect that it might end up costing more than repairing the current boat.

    Say you needed 4 sheets of good quality ply ($400), epoxy and fibreglass to say the outside ($200), some epoxy and fibreglass to the inside say ($60) lumber and fittings for framing inside (say $150) paint (say $150) - you end up a lot worse off, and you have to do all the building yourself. If you skimp on material quality, you will have to do it all again sooner.

    Marshmats idea of doing a full "instant boat" is good - you can get a certified and tested design built with a lot less aggravation of having to "invent as you go" and ending up with something that may not be totally satisfactory.

    For example, if you used the existing boat as a pattern, you would want to cut the panels to "pattern", take them off and stitch them together separately. Little innacuracies and annoyances of fitting the panels together, then deciding how much framing is going to make it a safe and robust, where to put decking, what shape to cut the decks, seats etc.

    In any case, I just bought Sam Devlins "devlins boat building" book, all about stitch and glue. Its a great easy read with lots of illustration for any "stitch and glue" project. That would be a great help - the DVD is very usefull too.
    http://www.devlinboat.com

    Good luck with it all, whatever you end up doing.
     
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  9. ancient kayaker
    Joined: Aug 2006
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    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    1/8 (3 mm) ply is not sturdy enough for a 14 ft boat that is broad enough to be stable and able to carry more than one person, although it is OK for a one person kayak. Although you can add stiffness with decks or a box structure, frames, thwarts and gunnels it would still not be strong enough for people to walk and bang around in, and the construction is starting to get complicated.

    GLASS: I don't use it so I'm not sure how much it would contribute, you would know better than I. Other than adding strength and stiffness glassing doesn't do much for a boat that is dry-moored (i.e., not left in the water after use) and it still has to be painted for UV protection; my wood boats get four coats of Latex house paint, abrasion-resistant porch paint on the bottoms, and a yearly touch-up. Works for me. Such a boat should last several years, longer if maintained, provided the joints are well made and glued, and care is taken to seal end grain especially under the waterline.

    WEIGHT: do you live near water so you can leave the boat in the water? If not transportation can be a design factor, if you have to car-top you will want light weight.

    COST: All-wood construction is easy and can be inexpensive. Pirogues are about the simplest wood boats, see http://www.unclejohns.com/boat/ for construction ideas. It also has plans for a jonboat but that's not as simple to build. They are very easy and quick to build, typically using 1/4 (6 mm) ply and up depending on size, cheaper, non-marine ply can be used; 1k budget should cover a small fleet! A pirogue can be paddled, poled and sailed, or even rowed although I haven't seen that done. A pirogue is double-ended but if you want to use a small outboard you can cut off a few feet to form a transom; but add a small deck to resist twisting at the stern or add bouyancy chambers which would also improve safety.

    CONSTRUCTION: stitch and glue is fine if you are using a kit or have plans with full sized developments of the flat shape of the planks, but if you use the aluminum boat as a form you don't need plans. You can use very cheap 1/8 ply called doorskin to make templates to transfer the plank shapes to the ply sheet. In Pirogue construction stringers or chine logs are often used to strengthen and stiffen the seams instead of glass tape and epoxy. You can glue 1-1/2 sq chine logs to the inside bottom edge of the sheer planks while they are flat, then bend them around the old boat and attach the stem(s) and/or transom, then plane the chine logs flat and glue the bottom, which can be cut over-size and planed to fit the sheers. If you add laminated gunnels (three lams is enough) on the outside of the sheer planks before lifting the boat off the form it will hold its shape while you add ribs, decks, seats etc. For the bottom, 1/4 (6 mm) ply is not stiff enough to support people without flexing, thicker ply can be used or it can be stiffened with cleats, or a floor can be laid over the ribs. Cleats are probably cheapest and provide a non-slip surface. Gap-free joints can be glued with Titebond III instead of epoxy unless the boat is left in the water in which case use epoxy throughout. My pirogue was entirely glued with Titebond and no fasteners were used, but it was small; for a larger boat screws are handy to hold stuff while the glue sets; stainless steel screws can be left in place.

    Pirogue: Pee-rog or Pee-row take your pick on pronunciation
     
    Last edited: Sep 26, 2008
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  10. chada
    Joined: Sep 2008
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    chada Junior Member

    Okay.

    I have decided to go with a different style of boat.
    Instead of the wrapping of the jon boat, I want to go with a

    Semi-Vee 2 Chine style boat
    preferably in the 14-16 class
    with a beam of no less than 4.5 and no more 5 ft
    would like to have about 10 - 12 inchs of freeboard
    preferably nomore than 5-8 inches of draw.

    Now I have been working with this software FreeShip and Chine Hull Designer.
    I think I have pretty much figured it out except for the WHERE'S the length
    and widths at for the planks.

    If anyone knows of an easier program please let me know.

    If I can figure out how to post a pic I will

    Just to give an example of what I would like to build.
     
  11. chada
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    chada Junior Member

    This is what I have been drawing

    [​IMG]

    This is the style I want which is basically the same shape.

    [​IMG]

    My daughter that would go with me.

    [​IMG]
     
  12. BHOFM
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    BHOFM Senior Member

  13. chada
    Joined: Sep 2008
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    chada Junior Member

    I have look at that site time and time again. There is nothing that appealing
    on there that I would like to have.

    Sites I been to:

    Bateau
    Glen L
    svesons
    and several others.

    I did like a couple on Bateau. Just seemed high on the price
    when everyone elses plan are around $40
     
  14. ancient kayaker
    Joined: Aug 2006
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    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Click on Tools, Develop Plates for pictures, in the new window click on Txt
     

  15. chada
    Joined: Sep 2008
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    Location: Florida

    chada Junior Member

    Thank You Ancient

    That gave me the some measurements for the Strakes.
    But still lost on the transom and rib framing.

    Chad
     
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