Precedent Of Building Hull Split Athwartship/Transverse?

Discussion in 'Boatbuilding' started by zstine, Mar 28, 2022.

  1. zstine
    Joined: Sep 2013
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    zstine Senior Member

    I'm aware of boats built in halves split longitudinally along the keel. Many Farrier trimarans were done this way and then halves were bonded together with a secondary/mechanical bond. Has any builder/designer built a bow half and stern half, then joined them?

    My shop is 28ft long. I want to build a 44 ft boat. blowing out a wall (concrete) and extending the shop (sits on property line) is not going to happen. I am curious if anyone has experience or if the precedent exists to build a hull in a bow half and stern half and join with a secondary bond? this is a FRP skin, foam core construction. I'm concerned that the bond area is much smaller than a longitudinal split like Farrier boats. However, a properly tapered and designed joint 'should' be possible.. right?
  2. BlueBell
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    BlueBell . . . _ _ _ . . . _ _ _

  3. Blueknarr
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    Blueknarr Senior Member

    No different from lengthening or shorting an existing hull.

    Your joint strength comes from breath not length.
  4. bajansailor
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    bajansailor Marine Surveyor

    This sounds like an interesting project - what type of 44' boat are you planning on building?
    As Blue Bell says, it is absolutely possible with a good taper.
    You could taper the outer skin of fibreglass as well, and have fibreglass laminate shear ties connecting the inner and outer skins over the tapers before filling in the void space in way of the tapers.
    You could also add some longitudinal 'top hat' foam core stringers on the hull in way of the join, for extra peace of mind. .
    BlueBell likes this.
  5. wet feet
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    wet feet Senior Member

    Quite a number of our local hire cruisers are laid up in sectional moulds,so that one bow section and one stern section can have any number of mould sections between them to produce several permutations of the same basic shape.I know of a few that exceeded the total length of moulds and which had a bow laid up ,as far aft as was practical and then with some bracing bonded in,they were released and moved further forward.Where after careful supporting and numerous shores to keep the hull in contact with the mould surface,the stern was added.The same treatment was used with the deck moulding.It ought to be noted that the area of use is inland and the design(s) have a flat sheer to allow for this type of variation.
    The Q likes this.
  6. DogCavalry
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    Fascinating stuff, @wet feet !
  7. zstine
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    zstine Senior Member

    Thanks for everyone's reply. It sounds like I can proceed with boat building... I don't have a specific design nailed down yet. This question was posted to ensure that building anything in 2 halves was feasible. That said, I have been sailing 30 years and raced much of that, but also cruised a year on our Tartan in the Caribbean. The Rapido trimaran is nice and Grainger has some DIY designs in that realm, a 42 and 50. Schionning has a weird 50ft tri with no aft cockpit or entry. You enter from the sides and the 2 cockpits are between the aka's like wings... not sure about that design, but it does allow for inside passage to the aft cabin. I haven't found other modern DIY tri designers..? The wife is more keen on comfort though. And she gets sea sick, so we are exploring the possibility of a design decoupled from sea state. maybe a pipe dream as that's not something available off-the-shelf, but intriguing to me as an Engineer.
  8. SolGato
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    SolGato Senior Member

  9. zstine
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    zstine Senior Member

    Ahh, yes.. Thank you SolGato for the suggestion. I have had a look at his web page, which is lacking. I wish he posted performance predictions, high resolution renderings and maybe some details about the design/construction and thought process that went into it... like his competitors do.
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