Estimating man-hours for hull welding

Discussion in 'Metal Boat Building' started by makobuilders, Jan 17, 2015.

  1. essenmein
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    essenmein Junior Member

    I have no experience wrt cost of welding a boat, I would go and see if you can talk to a yard with a sketch or drawing in hand.

    I agree that a yard *should* be able to estimate the labor involved in a build by the tonne, esp if you are building it with shall we say "normal" things, ie the less specialized stuff in there the more accurate historic cost/tonne data will be (for that yard and their methods). That number might be +/-20%, then as your design gets more complete and you can actually start pricing out processes and cuts, then you'll get closer to what might be called a "quote".

    We do this in our industry as well, first pass might be the affectionately named SWAG (scientific wild a$$ guess), a sort of finger in the wind estimate based on what it might have to do, as it progresses to a design you get a bill of materials, process flows, labor times etc and it gets more and more accurate.

    However if you are taking civil construction guys to weld a boat, and you can't talk to a yard or two about time, then you will unfortunately have to look at estimated weld length per tonne, estimated handling per tonne etc as well. This could be simple as saying plate is going to be 3/8 steel, a 7ft by 24ft plate is about 1 tonne, is about 60ft of welding, that might start getting you into the ball park.
     
  2. TANSL
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    TANSL Senior Member

    As we all know, not only it comes to measuring welding meters but knowing the throat of each, what position will soldering and welding machine which is to be used. Welding times can vary greatly depending on these variables. But, in addition, for a welder can weld two pieces, a tinker (maybe the word is not correct), should have attached them before.
     
  3. gonzo
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    gonzo Senior Member

    Have you revised your opinion?
     
  4. TANSL
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    TANSL Senior Member

    Gonzo, I have not changed my opinion, my friend. I do not know if I explain badly or if you are not able to understand. I'll try one last time. The meters of weld can be measured, although it seems a useless work that do not lead to any definite data, if anyone wants to know how many hours must be used for welding a structure.
     
  5. gonzo
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    gonzo Senior Member

    What is your criteria?
     
  6. TANSL
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    TANSL Senior Member

  7. gonzo
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    gonzo Senior Member

    That's a non-answer. Can you tell us how you estimate welding time?
     
  8. TANSL
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    TANSL Senior Member

    And how would I know?. Do not you realize how absurd your question? (I fear no). You know the boat ?, I don't.
    Besides all this, you do not understand I think it is not useful to calculate meters welding, or welding time?. I said shipyards have the data but, for now, I'm not a shipyard. And with "the data" I do not mean to weld meters but the hours needed to assemble and solder a boat. These data also are usually divided into the hours each workshop needs.
    But Gonzo, my friend, you do not know shipyard and I speak very poor English, so I find it a big effort to get you to understand something.
    Another day will continue, okay ?, now I have more important things to do.
     
  9. essenmein
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    essenmein Junior Member

    Yes ideally he should ask someone who knows, and someone that can estimate based on the design he has in mind.

    However, if that information is not available to him and I assume he still wants to build his boat with the resources available to him, then he must start somewhere, and a reasonable place to start would be how many welds, how long, how many passes etc roughly per tonne. If he has a boat in mind and size of sheet available, number of frames, how much forming etc, he can get a pretty good rough estimate as a place to start.
     
  10. TANSL
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    TANSL Senior Member

    Of course're quite right, I totally agree.
    However, meters welding is useless if, for example, it is unclear what position they are welded. The total length of the weld beads to be applied is not directly proportional to the "meters of joints to weld."
    If the OP gives me some drawings or sketches of the boat he has in mind, I will calculate easily the meters to be welded but I can not give him hours of welding his boat because it depends on him, his workshop, his cranes, welding machines, how, in what position will build everything, etc., etc.
    Hours / tonne to build the same ship may be different according to the shipyard to do so.
     
  11. gonzo
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    gonzo Senior Member

    TANSL: you keep on contradicting yourself. Either you calculate only by ton, as per your original post, or the position, etc. has to be taken into account. I am shipwright with may years of experience and can eyeball a job to a fair estimate. How many boats or ships have you built? Using length, amount of passes and adjusting for difficulty of the welds is a universal system that can be used to estimate a boat or a bridge. I can't see how the total weight of a product has a direct relationship to the cost of welding. It can only be used for products that are very similar. Vessels vary too much to make it a generic estimation system.
     
  12. TANSL
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    TANSL Senior Member

    You're right, Gonzo, your wisdom leaves me speechless. I do not know what could I say .... nothing.
    Goodbye, my friend, hope you do better, because I think your efforts to become someone deserving.
     
  13. makobuilders
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    makobuilders Member

    Guys, I think I enjoy the wise-*** remarks on this forum even more than the great info!

    The only way it could get better is if I tell you that DD 6-71's are the best engines in the world. I dare you to debate that!
     
  14. gonzo
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    gonzo Senior Member

    There are some that post snide remarks instead of information related to the post. Those of us with experience of actually building things realize that estimates have to take into account the difficulty of the job. For example, the inside welds of a chain locker can take a whole day. On the other hand, horizontal welds on the bottom frames go really fast. As for DD's, there is nothing wrong to like oil leaks;)
     

  15. waikikin
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    waikikin Senior Member

    Some here have declared their love

    How about 12V71's

    Jeff.
     
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