Building hull in cross sections

Discussion in 'Multihulls' started by SmallSpaceBigImagination, Mar 22, 2021.

  1. SmallSpaceBigImagination
    Joined: Mar 2021
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    Location: Toronto,Canada

    SmallSpaceBigImagination Junior Member

    I know the 1st rule of deciding to build... make sure you have the space.

    I don't. But what I was thinking is build multihull cross sections and store with multiple relatives/storage companies until time to assemble.

    Is this possible. Haven't decided on a plan but my primary build space would limit the beam to 17 feet, if I go this route...

    Prefer a multihull, likely motor because I'm new to boating. Plan to sail parts of the great loop - being in Ontario Canada. Ultimately looking for a sail to Florida at least a few times so costal is a must.

    Thanks in advance
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Do you mean the molds to build the hull over or sections of boat that you plan on joining together later?
     
  3. SmallSpaceBigImagination
    Joined: Mar 2021
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    Location: Toronto,Canada

    SmallSpaceBigImagination Junior Member

    Sections of the boat that I'll have to join together later.
    I have a total build space of 7ft X 19ft, but need some room to walk around and being a bigger guy...
    I think I have to ensure the molds start and end on a section. Maybe even duplicating the same mold section # at the start end end of each section to ensure the match up.

    Thoughts?

    Also thinking I'll have to find a way to make a flange on both sides to facilitate the join.
     
  4. TANSL
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    TANSL Senior Member

  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    That is not a good plan. It would be difficult for a professional to fabricate sections that will fit to each other. Also, the structure will have to be carefully engineered. Amateurs take 10 years or more to build a boat. Most abandon the projects. You need to ask yourself if the plan is to have a hobby building a boat or to go travelling on a boat. If the latter is the goal, then a used boat will be faster, cheaper and simpler.
     
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  6. trip the light fandango
    Joined: Apr 2018
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    Location: Rhyll Phillip Island Victoria Australia

    trip the light fandango Senior Member

    One possibility is to finish the bows a sterns in foam block, ideally cut out 3D printer style, but some foam is easy to shape.
    You then glass over it, 4ft each end is getting to the manageable limits I think, so 25ft would be the total. The final join/blend / fairing would have to be done with more room with gunwales and keel line needing sound overlapping and strong joins.
    You would want to be thinking the build is equally if not more important than using it, otherwise Gonzo's advise is better, including having it engineered, which maybe an alteration to a standard design, by the original designer,.. may not cost much, otherwise it is a risk, including resale.
     
  7. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    10 years seems a bit exaggerated, right? Also, at 3 or 4 years he would no longer be an amateur and the process would accelerate, I suppose. The goal seems to be "build" and no other. If he had wanted to "buy" he would have asked "where can I buy", or something similar. Since the OP apparently wants to "build" it is best if we encourage him with tips that will allow him to build the boat of his dreams.
     
  8. SmallSpaceBigImagination
    Joined: Mar 2021
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    Location: Toronto,Canada

    SmallSpaceBigImagination Junior Member

    like the foam block idea! i think I would need more than glass join thinking more along the lines of epoxy, mechanical and glass. Maybe glass 4 to 6 inches up the front / back of each section (join towards the bow and stern) to epoxy glue and screw each piece together - then glass over the joint and fair it.
    Being new to glass I'm leaning towards infusion to keep the pieces somewhat more consistent
     
  9. SmallSpaceBigImagination
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    SmallSpaceBigImagination Junior Member

    Im leaning towards long term project... My hobby used to be cabinet building, but there's only so many times you can renovate a kitchen. Although my wife may disagree.
    I can definitely afford boat payments but building would allow me to stretch out the outlay and avoid the Canadian boat lenders market. 10 years lines up perfectly with retirement for me... a time when i can go sailing :)
     
  10. trip the light fandango
    Joined: Apr 2018
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    trip the light fandango Senior Member

    The gunwales and keel line joins would overlap by say 18 inches, like 3 protruding arms[male] ,perhaps slide into forms[female] on the hulls.
    That system could be bolted on and therefore removable, for storage/ transport..
     
  11. redreuben
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    redreuben redreuben

    Sorry but this is nonsense. Building hulls and decks is only a third of the work.
    After assembly you still have fit out and engineering to finish ?
    Just go buy one.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    I quite like the idea of modular construction of a catamaran, but in this case the available space seems too little for the size being envisaged.
     
  13. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    SSBI, how big should your power multihull (probably a cat) be?
    What types or designs appeal to you currently?
    What is your realistic budget for this project, spread over a few years perhaps (I am being optimistic here, although very often 10 years turns out to be realistic).

    Once you have decided on the answers to these questions, go to sites such as www.yachtworld.com and do an advanced search for power multihulls for sale, and see what comes up. Google some other brokerage sites as well.
    You might well find a nice power cat that needs a good re-fit, that is within your budget - something like this would happily task your skills, and you would still have the satisfaction of bringing a boat (back) to life when you launch her. :)
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    Does anyone have references to boat hulls ( the part in the water I mean) that consist of parts that are joined together, and could be assemled/disassembled ? It certainly might help in situations where space is at a premium, or access is awkward to get something from the build point to the water. It can't be structurally unsound of course, and I assume the folding wings of planes on aircraft carriers say it is not unfeasible.
     

  15. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Building in sections is not a new idea. I would consider building it in aluminum. Within 17 feet allowing for 2 feet to work around each end you would be able to build in 13 foot sections. Two sections obviously 26 feet.
    You could make identical frames at the joints to ensure fairness and overlap the stringers and side stringers to carry the loads from section to section. Leaving the end of the plates tacked, you could relieve these as you put the sections together in a larger space, and weld the sections together. Of course I am assuming that this is a cat that you are building. The 7 feet of width is an issue and probably not practical for any material.
    The advantage of aluminum or steel for that matter is that the joint can be made as strong as the rest of the boat, without a lot of work.
    As you are a cabinet maker, working with panels will not be new and the tools will be the same. A circular saw with a carbide blade, jig saw, grinders etc. Of course the welding is a challenge but you can easily learn to tack the pieces together and have a professional complete the welds.

    re the 17 foot length, making the assumption that it is a garage, with a garage door, can you not build a temporary extension out the end of it. What is the inside height?



     
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