Question regarding Welding Aluminum baot upper deck

Discussion in 'Boat Design' started by Hunterr, Jun 14, 2015.

  1. Hunterr
    Joined: Jun 2015
    Posts: 29
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    Location: Korea

    Hunterr Junior Member

    the layout of our boat link : https://youtu.be/myQcQaoQsLw

    Our aluminum fishing boat pricipal dimensions
    LOA 10.4M
    LBP 8.66M
    B(MLD) 2.7M
    DEPTH(MLD) 0.85M
    DRAFT(DLWL) 0.25M

    aluminum : 5083alloy H321 made in Alcoa
    all thickness of aluminum plates of our boat are 5mm.

    A boat which have above dimensions is being built in our company and first ship.

    We are very dificient..T_T

    Today, we are getting into very large problem.

    Originally we intended to single welding upperdeck to side shell plate.
    But, Korea ship safety and technology Authority's inspector want us to double sides welding of upper deck.

    but, we can't weld beneath upperdeck. as you see our dimensions, the depth is very low. so worker can't get into under deck. besides, In the single weldingng, the depth of penetration is enough for a strength aspect.
    so we think that The double welding isn't needed and also we can't carry out double welding.

    But, the inspector want us to double welding.



    cf) There aren't any Law of welding less than 24meter in Korea.
    and also, there are no shipbuilding with aluminum company for Fishing boat(less than 24meter.)
    so, We can't find any case of aluminum boats in korea. help me..


    How shall i do?

    If u guyz have any information or photos that carry out single welding of upperdeck in aluminum boat, please send me as soon as possible.
    email:wonmin@sdn-i.com



    our all product lines stop now...
     
  2. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    If I understand you correctly...since you have not posted any pictures or diagrams/dwgs...

    You have 3 choices:

    1) Edge prep the plate then fully weld one side.
    or
    2) You need to full weld both side a small flat bat to the side shell, then you can fully weld, single side, the deck plate to the FB you have just welded...like a laptop joint.
    or
    3) Have rider bars acting as doublers, on your transverse frames. Cut slots into the plate and fully weld, by plug welding, the plate to the rider bars of the fully welded transverse frame below.
     
  3. Hunterr
    Joined: Jun 2015
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    Location: Korea

    Hunterr Junior Member

  4. Hunterr
    Joined: Jun 2015
    Posts: 29
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    Location: Korea

    Hunterr Junior Member

    yes, u understood corectly.
    1)=> this way isn't exsistent in korea standard and If we bend the aluminum, the crack would occur in the bending point.
    =X

    2)double side welding using FB => is denied by KST inspector.
    =X

    3)one side welding +plug welding=> I told this way to inspector and
    he said to me,
    "Give the other ship's photo using plug welding in the other company's case to me."




    so, If u have photos, Please email to me...
    I will compensate for your attachments of email.
     
  5. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    KST is a signatory of IACS. This is taken from IACS Shipbuilding repairs standards no.47:

    Slot welding -  IACS Rec47.jpg

    Thus, they must accept this, otherwise they are contravening their own rules of acceptance standards via by IACS.
     
  6. Hunterr
    Joined: Jun 2015
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    Location: Korea

    Hunterr Junior Member

    Isnt it regarding doubler plates?
    Are there relation between Doubler plate and Upper Deck?
     
  7. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    Makes no difference. Doubler/plug welding....call it what you like.
    It is very clear...you have a Flat Bar on the frame acting as a backing bar - or doubler - on the frame web..and then you cut slots into the main deck plate..and plug weld to the backing bar - doubler - on the frame. As shown and approved by IACS above.

    You can also tell him, all the South Boats in the UK have their main deck plug welded like this too.
     

  8. Hunterr
    Joined: Jun 2015
    Posts: 29
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    Location: Korea

    Hunterr Junior Member

    Thanks a lot.
    Now i am in the car to go to the KST authority.
    I will say to him as u said to me.
    If this way is approved, i ll compensate for u.
    Thanks!!♥
     
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