Going Further with Structural Design & Scantling with ISO 12215

[Pablo Sopelana]

Going Further with Structural Design & Scantling with ISO 12215

This course focuses on ISO 12215, the international standard for determining scantlings in small craft up to 24 meters. A continuation of the previous Structural Design & Scantling course, it expands beyond GPR materials and monohull sailboats to cover metallic and wooden materials, motorboats, and multihulls.

The course
This course is a continuation of the Structural Design & Scantling with ISO 12215 course. While it builds on key concepts and topics introduced in the first course, it also explores new areas not previously covered. In fact, whereas the first course focused primarily on GPR materials and monohull sailboats, this course will introduce and expand upon the following topics:

• Metallic materials, with some coverage of wooden materials as well.
• Multihulls.
• Motorboats.

In this course, we will briefly review the fundamentals of the strength of materials and the basic concepts to consider in marine structural design. This includes the stress-strain curve, methods for calculating the stresses in a beam, and the typical structural elements present in boat construction.

Additionally, the beam and shell theories briefly introduced in the first course will be expanded here. The Euler-Bernoulli and Timoshenko beam theories will be presented in detail, and Timoshenko’s plate theory will also be discussed. Next, we will study metallic materials, examining the metallic bond, the crystallographic structures found in metals, and how these affect their mechanical properties. Immediately thereafter, we will discuss some notes on aluminum and steel, the most widely used metals in the boat industry, followed by a brief overview of wood and its characteristics.

An introduction to the ISO norm will then be provided, after which the particular aspects concerning metals and motorboats will be addressed in detail before the concepts are applied to a real example. In this context, we will begin by examining a metallic motorboat case, calculating the design pressures, and determining the scantling for a stiffener and a panel.

Subsequently, we will cover the topic of multihulls. As usual, we will discuss the theoretical aspects of the norm necessary for understanding practical applications. The main peculiarity of this type of craft is that the norm considers global loads, and several practical examples will be presented.

Finally, the application of the norm to wood will be briefly introduced. We will first explain how the norm applies in this case and then work through an example of panel scantling.

What will you learn?
By completing this course, you will be able to design the structure and evaluate the scantling of motor yachts and multihulls by applying the ISO 12215 standard. More specifically, you will be able to:

• Comprehend the fundamentals of the science of strength of materials underlying the formulas and procedures described in the ISO 12215 standard. This includes understanding beam and shell theories used to obtain the practical expressions used in the norm.
• Understand the fundamentals of the structure definition process, including the various types of structural elements, structure types, and key concepts regarding the building process.
• Navigate the ISO 12215 Norm, understand different concepts and ideas presented therein, and the procedures to calculate the scantling of leisure yachts, with a special focus on metallic motorboats, sailing multihulls, and wooden boats.
• Apply particular guidelines to the design of the structure in the cases covered by the course, i.e., metallic motor yachts, sailing multihulls, and wooden boats.
• Determine the design pressures to be considered in the scantling process for metallic motorboats and multihulls, according to the ISO 12215 standard.
• Determine the scantling for panels (thickness) and stiffeners (section modulus) in the various areas of the hull for metallic motorboats and multihulls in accordance with the ISO 12215-5 Norm.
• Calculate the scantling for panels in the case of wooden boats.

Course organization
The course is video-based and on-demand, allowing you to learn at your own pace, wherever and whenever you want.

It includes videos, quizzes, and downloadable documents and provides access to the course’s virtual private classroom, where you can interact with the instructor and other students.

Upon completing all lessons, passing the quizzes, and having your course assignment approved, you will receive the Course Certificate.

– Resources:

• Video lessons.
• English subtitles.
• Written materials.
• Calculation templates (spreadsheets).
• Quizzes.
• Final Assignment.
• Virtual Private Classroom.
• Course Certificate.

 

[TANSL]

Hi @Pablo Sopelana. I can't access this thread. Have you blocked me? Are you afraid I'll expose existing shortcomings?
But getting to the very interesting topic of the thread, what do you think is the difference between structural design and scantlings?

 

[Ad Hoc]

..... what do you think is the difference between structural design and scantlings?

Indeed.
So...what do you think the difference is?

 

[TANSL]

@Ad Hoc, why is it that I love you so much?.
I won't answer so as not to give Pablo any clues, but I will say that, in my opinion, separating "structural design & scantling" of a boat, as if they were two different things, could indicate that you don't really know what you're talking about.

 

[Ad Hoc]

.... in my opinion, separating "structural design & scantling" of a boat, as if they were two different things, could indicate that you don't really know what you're talking about.

They are two very different things. So, clearly...

....you don't really know what you're talking about.

I agree you don't know what you're talking about.

 

[TANSL]

They are two very different things. So, clearly...

Okay, I see you're on the same level as Pablo on this topic.

I agree you don't know what you're talking about.

Once "your level" has been established, I'm not surprised you say this.
For my part, this concludes our very pleasant conversation. Thank you for your always intelligent suggestions.

 

[Pablo Sopelana]

Dear @TANSL ,

Thank you very much for your comment and for your interest in this subject and the course.

I completely understand the confusion. The distinction between structural design and scantlings can be unclear at first, and you’re certainly not the only one to wonder about it.

We address this point in the Going Further with Structural Design & Scantling with ISO 12215 course. By following the lessons, you’ll see how these two aspects relate, where they differ, and why both are essential. By the end of the course, you will have a clear understanding of what these two areas are and how they differ from each other.

I hope this helps!

 

[Ad Hoc]

... I see you're on the same level as Pablo on this topic....

I am on anyone's level. It is simple facts.

..... The distinction between structural design and scantlings can be unclear at first, and you’re certainly not the only one to wonder about it....

Indeed.
Since @TANSL cannot understand the difference, it is incorrect to assume that others do not share this point of view or actually understand, unlike he.

It is rather rudimentary.
Structural design is based upon theories, mechanics and mathematics.
For example, Instability is a structural design issue, so is Fatigue.

But scantlings, are the end result of using structural design to apply the theory into a physical reality to satisfy the analysis, i.e a real structural items, beit., a bulb bar, or a top-hat stiffener, shell thickness etc etc.

It seems @TANSL is unaware of this very simple difference between the two.

 

[TANSL]

Since @TANSL cannot understand the difference, it is incorrect to assume that others do not share this point of view or actually understand, unlike he.

I see that you are capable of knowing, without a doubt, what each person understands or fails to understand. Congratulations! It's a skill many of us would like to have. Since I miss it on many occasions, I have to limit myself to asking, hence my initial question.
The term "scantling a boat" is much more generic than "calculating the scantlings" of a boat's structure. The former includes the design of the structure, its general layout, with all the theoretical and practical aspects you mention, and (the second step) the calculation of its scantlings.
So, in my opinion, speaking of scantlings and the design of a structure as two different things is redundant. It would be quite another thing—on this I agree with you—to talk about designing a structure or to talk about calculating its scantlings.
Cheers.

But what does Pablo think about all this? It's him I was initially addressing, since he's the expert on the topic of his thread.

 

[Ad Hoc]

.... It's him I was initially addressing, since he's the expert on the topic of his thread.

He is not the author of the course.
So why are you not addressing your pointless questions (as you are unable to understand the difference) at them, rather than at Pablo?

 

[TANSL]

He is not the author of the course.

What course?. Who's talking about courses.
But, ok, talking about scantlings course, you seem unable to understand the obvious. I know perfectly well who the author of the scantlings course is, you can be sure of that, and I know that Pablo doesn't have sufficient knowledge to create any of the courses he sells. That's neither good nor bad; it's just facts, as you like to say.
I'm addressing the author of this thread, who has given it a title that is incorrect, in my opinion, so I ask him to explain himself and, if I'm not mistaken, to correct his mistake in that title.
It's best not to mention that course again. I think Pablo would be interested in not having it talked about anymore.
Since you're determined to keep Pablo from answering me, I'll refrain from responding to you from now on (as long as you don't once again express your usual and mistaken ideas about me).

 

[Ad Hoc]

What course?. Who's talking about courses.....

For the hard of reading:

Going Further with Structural Design & Scantling with ISO 12215

This course ....

...I'm addressing the author of this thread, ..

No you're not:

.... but I will say that, in my opinion, separating "structural design & scantling" of a boat, as if they were two different things, .....

You're questioning separating these two entirely different disciplines, because you don't understand why they are separate.
As you repeated here:

....I'm addressing the author of this thread, who has given it a title that is incorrect, in my opinion, ...

And as noted, you may have an opinion, but it is incorrect.

The author of the course is not Pablo.
The link provided by Pablo, is the title given by the authors of the course.

No wonder you don't know the difference between the two disciplines, if you can't comprehend the difference between posters from authors.

You are under no obligation to agree or disagree. But your opinion, is incorrect for the reasons previous noted:

...
Structural design is based upon theories, mechanics and mathematics.
For example, Instability is a structural design issue, so is Fatigue.

But scantlings, are the end result of using structural design to apply the theory into a physical reality to satisfy the analysis, i.e a real structural items, beit., a bulb bar, or a top-hat stiffener, shell thickness etc etc.
....

 

[Pablo Sopelana]

Dear @TANSL ,

To help clear up any confusion these two terms might cause, and in line with what @Ad Hoc mentioned, you can think of scantling(s) as the tangible outcome of structural design decisions.

I hope this helps to make the distinction clearer.

If you’d like to explore the topic in more depth, I warmly encourage you to take the courses:
- Structural Design & Scantling with ISO 12215
- Going Further with Structural Design & Scantling with ISO 12215

 

[CDBarry]

I was told a long time ago that the "Scantlings" formally speaking was the list of the dimensions and characteristics of the structure. It used to be a list in the specifications "... make it of gopherwood...". Now in a formal U.S. federal procurement, it is an item on the Contract Data Requirements List (CDRL), though often people call any item on that list a CDRL ("Seedrl") itself as well, so the scantlings would be a CDRL in the SWBS o85 group. It is a document, either self-standing, or as a distinct list on the structural drawings, or scattered all over the structural drawings, or as metadata in a ship product model. It doesn't contain much specific geometric information or details; the structural drawings or 3D model show those, and it isn't a physical object, nor does have any weight.

However, just as a list has become the name of an item on that list, the meaning of scantlings has wandered about, for example, some people use it to refer to the actual structure itself, or only internal framing itself, but not the shell plating, not a specific document.

And there is probably a lot of regional and customary variation just as there is throughout every aspect of ship and boat building. I remember being in the Gulf and thinking that "kevels and bitts" (as spoken) was a brand of dog food, not deck equipment, (and let's not even talk about Clydeside yards, especially when heard over the PA system).

These are some of the interesting things about this industry and are definitely learning opportunities. My favorite was asking a shipfitter about why a particular standard detail was used in that yard, and after thinking about it, he replied that this was a Lutheran (in the PNW) shipyard, rather than one of those Gulf Coast Catholic ones - as good an answer as any.

So, just roll with whatever works for whomever you are working with, and make sure you know what they mean by it.