A Question About Planking

There is a problem in expressing oneself in a language that is not one's own, but also in our own language there are fields of science that have their own language and are not easy to master. It is also necessary to have clear concepts to use the words correctly. In addition to these possible errors, I have committed others.
On two occasions, perhaps three, I have been wrong and I have spoken of "raising the scantlings" when in fact it was talking about "to change the scantlings". I have recognized, because it was true, that I had been wrong. So, let it be clear, my intention has been, not to ask for the increase of the scantlings, but for the change.
It seems to me to remember that I have also said that in order to know whether the scantlings increased or decreased (ie increase or decrease the weight) the structure as a whole would have to be studied, it was not enough to compare the boards of the hull.
Always, then, I have referred, I asked, or that is what I wanted to do, why a glued seam changed the scantlings.
I think with this we have already focused the subject.
I am looking for explanations in the Classification Societies on the methods to calculate the current boats of wood. If I find something that can answer my question, I'll let you know. I would also like to know how they were calculated, what formulas were used for the old boats of wood.
With all this we could know, why, how much and in what sense the scantlkings change when constructing boats of each system of construction. And we can also compare what happens, with the old regulations and with the modern ones. If there is anyone who can provide assistance respecting such regulations, I would be willing to do the comparative study and discuss it with all those who have time, knowledge and judgment.
(I have not kept my word. I had promised to stop talking, but the PAR post convinced me that this one, well taken, could be an interesting discussion).
If I have made a mistake again, please, tell me and I'll correct it. I do not try to misrepresent anything.
Thank you very much.

 

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Continuing my research, I have made the following discovery. Everyone who interprets it however he wants. I'll give you a clue, the weight of each cross section is proportional to its area.

It should also be taken into account that the two frames do not have to be of the same thickness or that the separation of frames can be different, ie one of the structures, we do not know which one, can have more frames than the other. So, imho, it's not so obvious, it's difficult, just by looking at them, which of the two structures is heavier.

 

A glued seam can be treated as a welded seam compared to a fastened seam, with its corresponding reduction in scantlings. That should be obvious; it is elementary engineering. Further, the images you show are not representative of two hulls built for the same service. The lapstrake is grossly thick and should not be thicker than carvel, but about 60% of it. Also, nibbed frames are a heavy way of construction. Steam bent or laminated frames are less than half the weight. This is not about interpretation, but simple engineering.

 

From the first moment I'm trying to know what engineering is used to know how they change and how much the scantlings according to the type of construction. So, apparently, we totally agree. It is necessary to speak of engineering and not of impressions or of what can be seen, which is little, in a cross-section. I'm glad to agree with you. With my previous post I meant exactly the same as you. Without engineering, nothing can be said. And without knowing the structure as a whole, it is absurd to make predictions about its greater or lesser weight or its greater or lesser resistance.
Another issue to be discussed is whether a glued seam changes, little or much, the scantlings. In my opinion, a strip with 4 fixed edges, regardless of their joining system, is calculated in the same way. It does not influence at all the method, glue, nails, welding, ... that is used to fix its edges. This is also, imo, pure engineering. It could be understood otherwise, I suppose, but then it should be explained the model used to calculate that strip (model = engineering. Engineering appears everywhere. What would we do without it, probably say things with little sense).
If I could know the method that you, the "experts", use, I could study the case and, perhaps, understand it.

 

To add to Gonzo's observation of the clearly incorrectly scaled figure, relative to one another of the shown parts, it also shows the overlaps far bigger than necessary for both traditional clinker and glued seam lapstrake builds, hence giving the wrong impression of extra materials and thus extra weight and costs.

One should look at these on the web given examples from an engineering point of view before drawing conclusions from them.

The wrong scaling of the shown parts, relative to one another, also applies to the shown lapstrake planks working width, which is very narrow relative to the shown hull depth, and so giving the wrong impression of more overlaps then necessarily needed, and thus giving the wrong impression of more materials and weight and work and costs than this build method actually has.

Taking my above reply to Gonzo's post into account, my advice to you would be to do as you said in the quotes below, and then come back with some well-founded discoveries and clues. - Good luck !

 

I agree, Angélique, I must learn and therefore, for some time now, I am asking for someone to help me, or clarify some affirmations.
It seems that what you are also convinced is that, by means of a picture, to say that a structure is better or worse, more resistant or less, lighter or less than another, is not very rigorous. I am glad, then, that you give me reason. Thank you.
I am asking for explanations for things I do not know and statements that I do not understand and, among other things, I humbly request, given my low levels of English and knowledge on this subject, that explanations are made in simple terms, trying to use technical words correctly, because otherwise I will not be able to understand anything. Expressions like "Except for pure tensile load ..." do not mean anything for me, or at least I am not able to understand them and can only increase my confusion.
Thank you, Angélique, I see that we are gradually getting closer in our positions.
Once all my shortcomings are revealed and reported my mistakes, following the philosophy and procedure indicated by Gonzo, could you, Angélique, please, give me data about the engineering that you usually use in the matter at hand?. Thanks, again.

 

I think this is the essence of the issue. I would advise you to read about bending moments and deflections in slabs and how it varies with type of edge support.
The usual definitions for an edge are unsupported, simply supported and fixed (where the edge is restrained so that a bending moment can occur).

In carvel the plank is unsupported at the sides and usually considered fixed at the frames, as the plank is continuous over the frame but if there is a join on a frame only one end would be regarded as fixed the other would be simply supported.
In clinker/lapstrake the ends are as for carvel but the sides have support, however rivets can not reliably transfer bending moments so the sides would be considered simply supported.
A glued seam can develop a bending moment, so more similar to a slab with 4 fixed edges.

 

You can maybe find texts in Spanish for cascos tinglados.

 

No, I do not seem, "cascos tinglados", to be the correct expression in Spanish. But it does not matter, we understand each other.
@latestarter, those are the explanations that I was looking for. At last ¡¡¡, thousands of thanks. According to what you say I seem to deduce that a glued seam, similar to a slab with 4 fixed edges, precisely because of that, will lead to less thickness of the boards. Which, I insist, does not allow extrapolation to say that the structure will be lighter. That depends on many other factors. Perhaps one could, for example, maintain the thickness of the boards and increase the spacing of the frames.
This is, then, the theory, which I know and understand : plate theory. Now what I would like to know is how this translates into practical formulas for calculating the scantlings of each element.

 

That is the compromise for any designer, trading off different factors to optimise the plan.
With a flat bottomed boat the calculation would be straight forward but once you introduce curves, especially in 2 directions, also chines, the hull starts acting more like an arch or dome so calculating that is beyond me.
It is that effect that allows canoes and other smaller craft to be frameless.
By the way, is this purely for your own amusement or do you intend to write a program to add to your portfolio.
Software for Ship Designers and Naval Technical Offices | Wix.com http://657677483.wix.com/tansl#!

 

This is, as I said before, a comment that made PAR and I found it curious so I decided to request more information about it. Unfortunately, to this day, I had received little more (thanks Rumars and yourself) than little friendly phrases, probably due to my way of expressing myself.
I have not found anybody who knows, or nobody wants to tell me, what formulas were used 60 or 70 years ago when the construction of wooden boats were more frequent than today. I am also trying to know which ones are currently used. I know that, for example, ABS does not update its rules for wooden ships since 1960, ie, it has no rules for these ships (if I'm wrong, I'd like to know how to get those rules).
I have not thought of doing a program for these calculations because, as you know, in the theoretical formulas you have to introduce many parameters and factors that are not easy to determine. And I do not know so much about this subject. Yes I have done a program to calculate scantlings for small boats, including those of wood, according to ISO 12215. But I am not a theoretician or an investigator. What I do is to prepare a program that will help the designer to perform some calculations that others have invented.
On my website, there are actually several programs related to naval architecture and shipbuilding. In them I have put my theoretical knowledge and practice of a fairly long professional life. My Gallery in this forum, shows some of my work during the last 10 years before retiring.
So, yes, this whole mess has been pure entertainment and the desire to go deeper into a field that I did not know about.
Cheers.

 

Probably the majority of boats with lapstrake/clinker planking in North America were small boats which were open or had partial decks, with weighed empty much less than a ton. I don't think many vessels of over 5 ton displacement were built with lapstrake/clinker planking. Generally the scantlings of these boats were based on the experience of the builder and what similar boats used, not on third part rules. ABS rules and similar applied to larger vessels.

 

I'll guess this is because the build method is limited to about an ¹/₂" planking thickness for plank processability reasons in lapstrake . . ?

 

Yes, I've seen Enavales has a YouTube channel that's presented by TAN s.l. / TANSL

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P.S. - For anyone who wants to see the last video with subtitles . . .

1) - start video is click on the screen

2) - look at the bottom bar - - to see the bottom bar: move the mouse cursor over the screen while the video is playing -

3) - click - 4^th button from the right = subtitles - - wait for speech for the subtitles to show up -

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- subtitles on = red notification bar under the 4^th button from the right -​

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4) - click - 3^rd button from the right = setting options

5) - click - subtitles

6) - click - automatic translation

7) - click the language of choice​

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→ - But beware, automatic translators make mistakes, especially in jargon !

 

Nevins, Herreshoff and Lloyds all had scantling rules back in the golden age of sail. These include lapstrake construction and all of the other more commonly employed build methods. The Herreshoff rule produced the lightest of the others and their America's Cup successes suggest these were up to the tasks asked. The Nevins rule was more for cruisers, than all out racers, but still well defined. The Lloyds rule was more of a set of recommendations that required approval, during submittal to the register or the Lloyds supervisor, before construction started.

I've seen traditional lapstrake hulls of 50' on deck and know of much larger vessels, though don't know the limit this would include. I've not seen any larger glued lapstrake hulls, though the potential is there for quite large yachts.

Try looking up Lloyd's Register Yachts and Small Craft Rules. It's been long out of print, but the used book market might have one someplace.