About To Lift Hull From Mold - See Anything Wrong??

Discussion in 'Boatbuilding' started by CatBuilder, Mar 20, 2011.

  1. CatBuilder

    CatBuilder Previous Member

    Here are a couple of pictures that how how my lift is set up. I have:

    *Temporary bulkheads at the even stations of my mold
    *Temp bulkheads are held in by ratchet strap (yellow)
    *Temp bulkheads have small, 4" (10cm) coves in 3 places to help hold them. These little coves are on the other side of the bulkheads, facing away, so you don't see them in the picture.

    Larger lifting straps will go where the yellow drawn in lines are in these pictures.

    **Note: There is only a bilge from station #6 to station #16. No deck, just a tiny topsides and a bilge. This is one of the half hulls where the bridgedeck connects. This is making me quite nervous.

    I plan to run longitudinal members all along the temporary bulkheads in the positions indicated by the two red lines. The one to the left in the picture will hopefully keep the hull from folding up like a "C" shape laying on the ground. The one in the middle will hopefully keep it from folding up like a "C" shape with the bow and stern in the air and the middle on the ground.

    Anyone see any problems, before I lift it, snap it in half and throw it in the dumpster?? :)

    [​IMG]

    [​IMG]
     

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  2. hoytedow
    Joined: Sep 2009
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    hoytedow Wood Butcher

    Put the narrow edge of the stringers against the bulkhead edges to take advantage of increased stiffness.
     

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  3. CatBuilder

    CatBuilder Previous Member

    Good idea, Hoyt. Will do.

    Think I can get away with 1x2's, or do I need to go to the store and pick up 2x4's?
     
  4. hoytedow
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    hoytedow Wood Butcher

    2x6's. This is not the place to skimp on materials, and you may need them later.
     
  5. hoytedow
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    hoytedow Wood Butcher

    2x4's will probably work but any job worth doing is worth overdoing.
     
  6. CatBuilder

    CatBuilder Previous Member

    Ok, I'll go pick some up tomorrow. Thanks.

    What about putting coves on the side of the bulkheads that is facing the camera?

    If you go to try and fold this thing up so the bow and stern are up and the middle is sagging, could that bend some of these bulkheads away from the side without a cove and toward the side with the cove? That would cause them to tear out, I think...
     
  7. hoytedow
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    hoytedow Wood Butcher

    Temporary blocks with tightly fastened small c-clamps on both sides of bulkheads should keep them from pulling across their planes. You could place 1x2's here that reach from bulkhead to bulkhead. Drawing to follow shortly. Colored line will represent 1x2.
    What do you think?

    You can never own too many clamps!
     

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  8. CatBuilder

    CatBuilder Previous Member

    Too expensive, Hoyt...

    I have plenty of clamps, just not that particular type. I'd have to go and buy another 36 clamps just for this lifting project.

    Wouldn't it be cheaper (and just as effective) to duplicate my little bog spots on both sides of the bulkhead?

    Also, just noticed that I can't do the c-clamps anyway. The mold battens are in the way for that.

    BTW: How do you do these drawings?!? Are you hand drawing them and scanning them?
     
  9. hoytedow
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    hoytedow Wood Butcher

    That's true, but if you saved the receipt and took them back for a refund undamaged, what have you lost?(Not that I would ever do that) Small clamps 1.5" are very cheap. You know, the little metal ones that say china on the sides.
     

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  10. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    What are you lifting this with? If some sort of crane make a spreader bar almost the full length of the hull. To do this you need to glu up two opposing 2x6s--one flat and one nailed in vertical like an L. each piece being a 2x6. spice them together and add a scab at each joint 36"-2x6. Use 4 lifting points eye bolts are fine. there will be little if any flex but the flat 2x6 must be secured to the hull at each bulkhead--a strong connection....This is called a strongback and is used where ceiling joist are over spanned. You can use strong channel or even angle stock to equal out the lift. This is stronger then the method Hoyt drew out.
     
  11. hoytedow
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    hoytedow Wood Butcher

    Some I hand draw. Some I draw in paint on computer. Latest drawing I did was to draw an ellipse, chop off the top, copy it and reduce it several times and line it up on two black lines to give perspective. Easy Peesy.
     
  12. hoytedow
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    hoytedow Wood Butcher

    Put the blocks on the underside of the 2x6 all the way down will keep all the bulkheads at set distance.
     

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  13. CatBuilder

    CatBuilder Previous Member

    Be back on in a moment. For now... here is a picture of what I'm lifting the hulls with.

    I have a pair of these... one for each lift point. I planned to lift it with slings, just like a Travelift:

    [​IMG]
     

    Attached Files:

  14. hoytedow
    Joined: Sep 2009
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    hoytedow Wood Butcher

    My last sketch of course shows the 2-by upside down for illustrative purposes. Each bulkhead braces all the rest so no one bulkhead takes all the strain. It is also drawn without the side piece(which makes it L-shaped. Here is another.:
     

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  15. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    That should work. I would use 2 straps for each crane giving you 4 lifting points.
     
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