HELP! Hull is Sagging! I don't know what to do!

Discussion in 'Boatbuilding' started by CatBuilder, Mar 21, 2011.

  1. CatBuilder

    CatBuilder Previous Member

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    Today, even though I had a fever, I decided to fit the L beam and lift the hull out.

    Looks great!!

    [​IMG]

    Of course, just my luck with these things, it wouldn't come out of the mold. It missed by about 1" (2.5cm). :confused:

    [​IMG]

    [​IMG]


    Time to cut the side of the mold off, I guess.

    The really bad news is that if this half hull can't clear the side of the mold, I think this means my full hulls won't be able to be lifted off, even if I cut the side of the mold off. :(

    Building the hull was great. Moving it? Not so much.
     

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  2. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    So the strongback worked and was strong enough? When you build the other half can you cut away the form all together and build another so you can mould the hulls together with the keel facing the ceiling then you can completly finish tthe bottom before flipping it over.
     
  3. CatBuilder

    CatBuilder Previous Member

    The strongback was WAY more than strong enough. I did it like this:

    *2x6 on the vertical and 2x4 on the horizontal.
    *36" gusset/scabs at the joins, which were staggered.
    *14 screws on each side gusset/scab, total of 28 screws per scab
    *Titebond glue on every join, including the length of the 2x4-2x6 join
    *Screws joining the 2x4 and 2x6 about every 4-5 inches

    No trouble with sagging.

    Interested in your suggestion above, but not understanding again. Scrap the mold? :?:
     
  4. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    No, once you get the 2nd half made and out of the mould or take the mould apart to get it out you make a new form to put the halfs on upside down so you can finish connecting them then totally be able to finish the bottom of the hull as it is now facing you and much easier to work on. This includes all painting to be complete. That form is just 2 long 2x6s spaced 4-5-6' apart depending on the beam width. put legs under the 2x6s to raise the hull high enough to get under it to finish tying the bulkheads togther and install the keel all for complete structural strength so you can flip it over to do all the topside and interior work. Need to build a new cradle for that but the bottom is all done.

    It looks like the hull would clear the form if you could tilt it up on the low side with a couple of 2x4 blocks.
     
  5. cthippo
    Joined: Sep 2010
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    cthippo Senior Member

    Can you jack up the far side of the mold to allow the near side to be lower? Or maybe move things around so the cranes are lifting from the low side?
     
  6. CatBuilder

    CatBuilder Previous Member

    I think I'll try putting a few sheets of plywood down below the mold to get my cranes up that extra inch or two...

    Or any of the other ideas if that doesn't work.

    Should come out, I think. I was too sick to work too hard today. Didn't want to be laid up for a week sick... so only did a basic lift.
     
  7. hoytedow
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    hoytedow Wood Butcher

    It looks great. I knew you could do it!
     
  8. hoytedow
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    hoytedow Wood Butcher

    Next time, put the high side of the mold toward the wall, away from the engine lifts.
     
  9. CatBuilder

    CatBuilder Previous Member

    Thanks, Hoyt! Very encouraging.

    Guys, I'm not sure what you all are seeing in the pics... must be something about the angle.

    There is no "high side" or "low side" to the mold. It's 100%, perfectly level in every way. It's made from vertical sheets of 4x8 Advantech that are perfectly leveled. All sides are exactly the same height.

    The tipped angle of the hull itself is from that "garbage can lid" effect I mentioned earlier in the thread. The hull is tipping as it hits the arm of the lift.
     
  10. hoytedow
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    hoytedow Wood Butcher

    So what you do is take the side closest to the wall and jack it up an inch or two or shorten the legs closest to the engine lifts.
     
  11. hoytedow
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    hoytedow Wood Butcher

    If possible.
     
  12. AndrewK
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    AndrewK Senior Member

    Congratulations, since you are so close clearing the mold definitely build some mini ramps so to speak to go under the hoists (scarfed plywood).
     
  13. hoytedow
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    hoytedow Wood Butcher

    Shhhhh! Don't say scarfed! :D:D

    There is a lot of useless wood under those battens. You could make the whole mold shorter while it is empty!
     
  14. CatBuilder

    CatBuilder Previous Member

    Actually, you can't. The mold is a certain height so the hoists can roll under it.
     

  15. rberrey
    Joined: Oct 2010
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    rberrey Senior Member

    Looks good Cat , can you put casters under the mold and pull it from under your hull? rick
     
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