steel removal

Discussion in 'Metal Boat Building' started by Dave Patterson, Mar 15, 2011.

  1. Dave Patterson
    Joined: Apr 2010
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    Location: Northfield, MN

    Dave Patterson Junior Member

    I am in the process of replating the bottom of a 28' V hull work boat. The steel is badly corroded 3' on either side of the keel due to sitting water. The longitudinals and frames are solid. The keel is 1/2" x 6" steel and the longitudinals are 3/16" x 2" spaced 10" apart. I have cut all the stitch welds to the frames and the longs and have removed 6' sections of steel from the bow. Would the framework of the boat be strong enough to support itself if I remove all the rotted steel from the bottom at once or do I have to do it a section at a time? It would seem to be easier to do the prepping and patterning with it all removed. The boat is blocked under the keel at the stern and bow and is also supported by 4 heavy jack stands.

    Thanks,
    Dave
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You can weld tabs on the sides to support the hull with legs.
     
  3. micspoko
    Joined: Jul 2010
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    micspoko Senior Member

    don't remove all plates in once. I would do it this way: first replace at the bow and stern after thet on midship
     
  4. Dave Patterson
    Joined: Apr 2010
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    Location: Northfield, MN

    Dave Patterson Junior Member

    I should clarify that the blocking under the keel and the jackstands will stay in place when the plate is removed. I was mainly wondering if the boad structure is strong enough to maintain its shape with all the rotten plate removed at once.

    Thanks,
    Dave
     
  5. micspoko
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    micspoko Senior Member

    how big plate is to removal. maybe some foto
     
  6. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    ...best to play safe and weld the hull to a cradle or support. The last major metal plating repair I did we welded to a cradle and the vessel still changed shape enough that many doors, hatches needed to be re seated and the engine needed to be realigned.
     
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  7. welder/fitter
    Joined: Jun 2008
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    welder/fitter Senior Member

    Better to do it bit by bit, supporting sections before removing plate.
     
  8. NZ_Shipwright
    Joined: Sep 2010
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    Location: Auckland

    NZ_Shipwright Junior Member

    Hi, If you can figure out the way it was originally plated by weld seams and a bit of CSI replace each one as you remove rotten one by one. Plate by plate dont get too far ahead of yourself.
    regards NZ
     
  9. glasser
    Joined: Mar 2011
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    Location: westcost Canada

    glasser HELP U IF I CAN

    re steel removal

    working on steel you shooed allies play it safe you shooed before you start removing sections back brace the framing by adding temp steel bracing side to side and cross sections this shooed help it stay in shape as welding the new steel in and even the removing of the old steel may change the over all shape to the point of needing to have doors hatching motors shafts real ind
    as a rule before starting a big job such as this you need to brace it first i no this can take time and some money but in the long run is the best way to do it best of luck hope all go good for you
     

  10. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    If you do the repair bit by bit it will take longer and you risk distorting the hull more. Any professional will cut the plates and then weld them. Also, you should stabilize the hull. Jackstands are not adequate. You need to weld either well secure legs or a cradle to the sides and keel. It is easy to cut the attaching points and grind them flat later.
     
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