The good, the bad and the ugly - Steel building methods that is....

Discussion in 'Metal Boat Building' started by Wynand N, Aug 18, 2010.

  1. Ad Hoc
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    Ad Hoc Naval Architect

    There is no perfect solution, never shall be. Each have their own merits and each are better suited for some applications more than others.

    As with anything it all depends on the focus of the objective. By that I mean, a welder will want minimal welding, a designer will want easy drawing and owner will want cheapest cost and so on. Thus each person in the long chain from designer through to owner, each one shall have their own opinions or preferences, from their point of view.

    Bottom line is, what is YOUR objective.

    YOUR objective will always be different from someone else’s, and as such, the preferred method shall also be different. NOT better, just different.

    If you can get a hull made from Switz cheese to pass strength requirements, for example, then there is no reason not to use this, if that is YOUR objective.

    Which ever method you select, you need to satisfy yourself, and probably to others, why you have selected the said method. Generally in terms of costs, weight, safety and man hours. But, if the method selected passes all the basic criteria of strength, stability, safety etc etc….who cares? That is the beauty of design and boats…they are all, generally, different.

    As a naval architect, the only preference I have is that is satisfies the clients SOR and as such passes the basic requirements of strength, safety, costs etc, that’s it. Whatever is then selected is for others to debate the pro’s and con’s, but that misses the point. If the objective (SOR) has been satisfied, does it matter if the boat is made from Switz cheese or made frameless or whatever? One must look at boats, holistically, not just in the details alone. If it does the job, end of story.

    Others may differ in their view….
  2. rugludallur
    Joined: Jan 2006
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    rugludallur Rugludallur

    My two cents

    Design and engineering is all about compromising, what's right for one person might not be right for another due to differing requirements.


    Some who never go above or below 60° probably won't ever have to deal with brittle fracture so mild steel is acceptable while others need shipbuilding steels.

    If you don't care about cosmetics and live in northern latitudes you can usually get away with 304 stainless rather than 316.

    For someone who only sails a couple of days a year but lives on-board the whole year around chines are really only a cosmetic issue and the reduced build time might allow them to get a boat with a bigger interior.

    Regulatory authorities differ, in some countries (like mine) you have to submit drawings to a review by a government institution which reviews all calculations and since I live in a northern country all boats here have to be able to withstand pack ice. In my case this meant adding frames to my frame-less boat and increasing strength in the bow. There is also a requirement here that all shipbuilding steel must be at least Grade A and certified, no mild steel.

    Some generic things I have learned for myself throughout the process of building my boat include:

    Get pre-primed plates and get the biggest plates you can handle and source, I was able to buy pre primed 3mm 6m x 2m Grade A shipbuilding plates, my plates were rolled in Holland, if anyone wants I can look up the mill and send you some contact details. By using pre-primed plates welding preparations before and after are substantially reduced, cleaning before can by done with a simple wound wirebrush in an angle grinder, spatter won't stick to the paint and you won't get any mill scale into your welds. I also use wash primer to touch up an area after I'm done with all the grinding, makes it obvious which areas are done plus I don't have to worry about spatter from other welds sticking to the bare steel.

    Have your hull sandblasted inside and out, even if you get primed plates. I spent loads of time talking to guys from Hempel and Jotun and since they don't have anything to gain I think their advice is good. When the big paint manufacturers sell marine paint for a larger ship they actually sell it with a warranty, they are responsible for the paint scheme holding up for anywhere from 3-10 years and these guys are responsible for supervising and certifying that proper procedures were followed when the paint was applied. The primary reason why marine paint fails is improper surface preparation, not only does the steel need to be clean it also needs to be of a certain roughness. I'm not saying that you need a Frosio certified inspector to come over but at least follow their advice, it's given for a reason.​

    Then again, someone else might not mind repainting every couple of years or spending more time redoing welds or cleaning up spatter.

    My requirements include the boat lasting 50 years with minimal maintenance, this increased the cost and time for building but I think in my case It will be worth it in the long run.

    1 person likes this.
  3. apex1

    apex1 Guest

    Think I should post it here again............

    .....when even Welder /Fitter can find something interesting in there, how much value it might have for the novice....?

    As a sidenote:

    I don´t really understand why the so called "Origami" method became the main focus again here!?!?!??

    It is by far the least interesting method for both, the novice and the pro.
    In fact it is not even a "method" when we look at it from a scientific point of view, because it applies only and exclusively to ONE single hull shape and size (within a few feet).
    A real "method" would apply to many varieties of the same theme.


    welcome here Brent (waterdrop)
    ...not really welcome...

    Attached Files:

  4. Milan
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    Milan Senior Member

    Links for the different “skin first” building systems:


    Van de Stadt:

    Meta, strongall: (look at the Äntarctic” and Beateaux – “Metapassion”).
  5. welder/fitter
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    welder/fitter Senior Member

    I bought an unfinished Denis Ganley passenger/cargo/fishboat hull from a Aussie fellow who was too old to complete it, in The Philippines, in 1991, along with the plans. I didn't see the design on the Ganley site - thanks for the link, btw, I didn't know it was finally up - but the plans were extremely complete and, along with a lot of spec.s sheets, there were drawings for all systems, alternatives for fish holds, a choice of building it for fishing, cargo, passengers, etc. . I would have bought the plans for the s.v."Ace 3", but the place in the U.S. that was building them went belly-up before I could arrange contact with Denis Ganley's daughter. I bought plans for a Ken Hankinson design, instead. I've heard a lot of good things about his sailboat designs, but haven't been on one yet.
  6. welder/fitter
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    welder/fitter Senior Member

    Thanks for the info. ! I'll be building in the Southern Philippines, again, so hopefully I'll be able to get large sheets, as there are a few very large shipyards there, now(two of the world's largest, in fact). When I was there in the early 1990s, steel plate was much cheaper there than in Western Canada. I'm hoping that with the close proximity to China, it is still that way. I've heard, however, that the quality of steel there fluctuates a lot, these days. Unfortunately, it is not easy to research from Vancouver.
  7. welder/fitter
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    welder/fitter Senior Member

    I don't think that many of us are that interested in debating these above-mentioned boats. I think that many of us would rather just talk about all methods than focus on one. I also think that that is why Wynand started this thread. I could be wrong, though.
  8. magwas
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    magwas Senior Member

    You may have missed comment #2, linking to the thread
    So origami is clearly a method, applicable to all shapes and sizes.
    You may not like origami, but there are others who do. Hence it is definitely interesting for some of us.
  9. apex1

    apex1 Guest

    again you show your complete ignorance on another topic.

    I have missed nothing here in the past five years. But different from many blind followers of some sort, I was willing to broaden my horizon and followed links provided here, or studied the topic in my yards.

    I am dead sure you have not even read the comments M. Kasten made on the topic.

    It has nothing to do if we like one material, method, style or what so ever, facts are facts.
    And the so named "Origami" way of building a boat is restricted to roughly one shape and size only. period

    Go study before you contradict professionals!
  10. Wynand N
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    Wynand N Retired Steelboatbuilder

    You are correct Mike.

    This thread was created to discuss all methods of boatbuilding in a civilized and polite manner. Nothing wrong mentioning origami in the mix as it is an alternative to more traditional methods and by giving opinions, discuss the pros and cons from such a post that may arise in the mix from time to times wont hurt.
    That said, this thread was not started to discuss and promote origami as such as this would result in the very reason why most of us just got fed-up with a certain individual(s) pointless and rude rants to promote that method on the Origami thread...
    If anyone want to discuss origami only, rather take such posts to the Origami thread that's there for that very reason..

    I read and reply to this post earlier to be polite and informative. BUT, Waterdrop, alias Brent Swain, please do not insult our intelligence. This quote spells your name, hijack methods and to prevent what will come from you here as a poster, keep your origami promotion, arguments etc for the origami link, because you are a destructive and not a constructive poster.
    Refer back to post #1 and READ the preamble.

    Gentlemen, lets hope this individual will take heed from this and we can carry on with a worthwhile thread where all of us can gain from.
    If he knocks again, perhaps get Jeff to intervene...:confused:
    Last edited: Aug 19, 2010
  11. magwas
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    magwas Senior Member

    I would say that a 3.8m kayak and a 40 ft sailboat are not even roughly the same shape or size. From the writing of Kasten it is obvious that he is not aware of the design methodology which turns any developable hull shape into an origami layout, and described in the linked thread in post #2.
    For example I have more than 250 different carlson .hul files on my disk, all downloaded from the internet, and all of them could be turned to an origami plan in less than an hour.

    Also the question of mechanical strength and frames is not entirely relevant when we are talking about origami. In one hand, with adequate hull thickness one can avoid having frames up to a certain length. In the other hand as I figured from building logs, longitudinal strengtheners are part of even at least some of Brent's designs.
    Regarding transverse frames I do think that they could be incorporated to the building method rougly the same way as longitudinal ones had been done: weld to the flat plate, bent with it and ends weld together. So I do think that even most of the arguments about frame first vs frame last are irrelevant to origami method.

    Yes, there are very few (if any) mechanical calculations done on origami designs so far. But it is not inherent to the methodology. I guess it have much more to do with personal issues and the "market position" of these boats. I have the feeling that most of the cheap plans come without such calculations. Someone in an other thread have plainly stated so when someone have brought up some stability related question and I naively said that I would not build a boat above 20 ft without proper stability and strength calculations (which I still think so).

  12. apex1

    apex1 Guest

    Well, prove it as often as possible, in the end all around here will get it, that you never know what you are talking about.

    You are referring to the "plate first" method when you say "Origami", but these are quite different animals.

    It is NOT the case, that every developable shape can be done as a "Origami" hull. At least not when designed to efficient and safe properties.
    The fact that one can build it does not mean it is a boat one would like to sail.

    Though Terho made some very impressive effort.

    Sorry Wynand, would all have been said better on the "other" thread...........
  13. Wynand N
    Joined: Oct 2004
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    Wynand N Retired Steelboatbuilder

    There is one building method I complete forgot about in post #1 and believe it or not, actually the FASTED way to get a hull in shape. So fast in fact, it takes just a fraction of a second...:D

    About 25 years or so ago I had seen this article in a boating magazine of a company in I believe was Australia and I stand to be corrected. Photos was shown of this process in the article and go something like this;

    1. The shape of the hull is formed IN the ground with concrete and smoothed.
    2. Aluminum plates lain inside / across the "hole"
    3. Explosive charges laid and on goes a lid.
    4. Big Bang, smoke and out pops a perfectly shaped round bilge hull.

    Perhaps someone reading this seen it too. Would love to have that photos posted here - If one can just find them.

    PS: Just found this link - article and photos on this method and the boat called "Gelignite":
    Last edited: Aug 19, 2010
  14. magwas
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    magwas Senior Member

    Time to prove a point you made: It is NOT the case, that every developable shape can be done as a "Origami" hull.
    Give me any developable shape in any format that freeship can import, and I produce an origami layout from it. Note that per thread rules you should either give evidence or shut up.

    As any developable shape can be built as origami, all the developable hull forms which are "designed to efficient and safe properties" can be built as origami. QED.

    My understanding is that "plate first" refers to all methods which build the plate first, before (possibly) building the framing. In this respect origami is a method which is a subset of plate first, the differrentiating property being that in origami you start with a layout which contains more plates in a cluster which would be separate ones otherwise.
    If your definition differs, then first we should agree on the meaning. I don't give a damn if you call origami with any other word, just meaningful debate should be done on the same terms.

  15. apex1

    apex1 Guest

    ......senseless as it is so often.

    I don´t go to destroy this thread or to make another "Transverse Frames" or "Origami" drivel thread out of it.

    over and out here
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