can it be done in steel?

Discussion in 'Metal Boat Building' started by tugboat, Jul 25, 2013.

  1. tugboat

    tugboat Previous Member

    this is a final follow up question for those with knowledge of steel tug boat building.

    please review my previous thread titled-
    "new 30 ft tug design(which material?)" thread posted earlier this week if needed. it explains where I am at. I really want steel as the material.

    my question is easy fast and simple.
    could this design be built without too much difficulty(relatively)straight forward in steel?

    scantlings :
    hull 10 gauge
    deck 1/8th
    keel,hornbeam and stem 1/2 inch.
    rudder 1/2 inch
    frames 1/4 inch

    stick process.

    willing to roll sections if necessary.
    but will heat applied help? could it all be cold formed?
    I have decided if this could be done relatively easy, then its going to be the choice of material.

    please see pics to help determine.
    is there a pro steel boat builder out there with experience in radius chined counter sterns? who could answer this?
    my thinking is -it shouldn't be too difficult since other older tug hulforms were built to even more difficult, round bilge and radius chined hull forms...
    but I'm not certain.


    thanks
    Doug aka Tug
    p.s I can provide other views of the hull if necessary. or explode surfaces too , if needed...
    :confused:
     

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  2. TANSL
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    TANSL Senior Member

    Almost any shape can be made ​​of steel, if you have the necessary tools. But some of these tools are very expensive. The best thing is to cold form plates as heat can get to impair the mechanical properties of the material.
    There have been, we all know, steel boats with much more complicated shapes than yours. However, in your case, it might be interesting to use only ruled surfaces.
     
  3. tugboat

    tugboat Previous Member

    Hi Tansl. thanks for your post. Positive feedback on my threads are always welcome. there have been trolls...

    anyway I figured anything could be done in steel.
    let..t me explain here- I have looked in depth at every possible material.
    Ill list them
    frp, fal, steel, core strip planked and sheathed strip.
    I am unyielding when it comes to what I need(want?) in a design. and a radius chine form is about # 1 in the design arena. I don't mind rolling anything its not too expensive...but the design MUST be this one. as designed. I am uncompromising on that...
    if people here seem to think its do-able- without too many major ***-aches its good to go...
     
  4. TANSL
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    TANSL Senior Member

    You will be surprised to see how much you can bring your forms using ruled surfaces.
    The rounded bilge will not be possible to achieve but something very, very, similar.
    The job of a tug is very rough so the best material, in my opionion, is steel.
     
  5. tugboat

    tugboat Previous Member

    Sorry Tansl- I made confusion- it was supposed to read "radius chine is my #1 priority"... not round bilge-

    I always get them confused...I think your right steel is the way to go!..do you think the radius chined is doable? lets put the HC concept on the backburner for now...
     
  6. TANSL
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    TANSL Senior Member

    : Of course, but results in double curvature surfaces which, always, are hard to get.
     
  7. tugboat

    tugboat Previous Member

    to me if its doable- I am confident that I can get results...this gives me Hope Tansl.

    funny thing:
    when I costed out the other materials none were as cheap as steel but when you figure in sandblasting tooling and other things- it is slightly more.

    still for durability you cant beat it. tugs need to be heavy. so it works ...
    I now have to build a gantry- buy a good welder. and a genset since Ill have to run the welder off of a generator.
    how hard will it be to have someone roll the radius section??..do you think the radius section is all that needs rolling?

    thanks!!
     
  8. TANSL
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    TANSL Senior Member

    It will probably be the only thing but it is hard to tell without seeing the lines plan.
     
  9. DCockey
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    DCockey Senior Member

    I don't have any experience in steel boatbuilding so ignore this note if you'd like.

    In the previous thread thread you mentioned the surfaces of the design you showed there are not developable so it would be difficult to build in ply. Is that still correct? If the surfaces are not developable then you'll have to have a method to put compound curvature into the plates, or use a number of sufficiently narrow plates so that the resulting faceted surface is close enough for you to the compound curved surface.

    I've seen mention of creating a rounded chine using short sections of plates, each rolled or bent into a cylindrical surface.

    You can't have both straight frames and developable surfaces (unless the bottom has constant deadrise and the sides have constant flare). Associated with that is not all ruled surfaces are developable.
     
  10. tugboat

    tugboat Previous Member

    truly I appreciate all comments on this-
    that's true- you cant have straight frames and non developable surfaces...but I have seen M&M Ovendens ( a poster o this site) boat and they have a radius chined hull . it s magnificent. if you can find the thread but the boats is called the Pepe Barou(not my choice in a name for a boat but...)- to my knowledge they did not use any rolling or flame treating to get the radius and it has far more than the tug. (for some reason though they seem to have stopped building in 2010 I cant find anything after that on their boat?).

    - one thing I didn't mention- the area where the radius chine is- becomes flat as it reaches the aft section. its hard to see on those pics. but it is actually largely developable. so it MIGHT be able to be plated simplistically with standard equipment. im prepared to invest in some good equipment. I believe its doable now. but it might involve rolling - but the shop rates here are pretty good at 55.00 per hour. at least it seems pretty good to me.
    I don't know what the time is to roll a few sections of plate but it cant be more than a few hours.?? especially if the plate is not needing lots of passes through the roller.
     
  11. DCockey
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    DCockey Senior Member

    Building a model using thin cardboard or sheet metal for the plating might provide some guidance on how to arrange the plating and how much shaping will be need.
     
  12. DCockey
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    DCockey Senior Member

    By the way, nice job with the Rhino model.
     
  13. tugboat

    tugboat Previous Member

    Thank you very much!
     
    1 person likes this.
  14. Titirangi

    Titirangi Previous Member

    To build any shaped hull with steel is possible, hard chine with forgiving curves (no compound curves) or round bilge. Shaping steel plate with rollers, brake press, hydraulic press with formers is relatively easy if you have experience/trade skills or access to workers with training. Compound curves are difficult but very doable with the right equipment and skills.

    Many yards in Turkey fabricating steel round bilge hulls 12m to 50m use a combination of chain blocks (standard shipyard practice) with heavy 4x4 forklifts fitted with single long fork to shunt plate into position against frames.

    I would point out as incorrect that heat doesn't impair or damage plate steel, unless you heat to sparking white to burn the steel. White heat causes huge oxy saturation making steel incandescent. Heat isn't used because its both unnecessary and too expensive.
     
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  15. tugboat

    tugboat Previous Member

    This was of significant help to me- thanks!! I will probably use chain hoists to pull my steel in. and a steel gantry
     
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