Scantlings for cement (IE Books?)

Hi, all. I am wondering about cement scantlings. There are a lot of books on Amazon about cement boat building, but by the title it seems more about building than designing. Can anyone recommend a good book on design? I'd perfer calculations but even a reference that says this thickness and steel for this scantling of plywood/Alum/Steel would be a better start than I have now.

Cheers,
- J

 

Designing ferro boats (cement) is exactly the same as any other hull shell material choice. You calculate the loads and capacities you need, then develop a shape, arrange the masses, in hope that everything balances out nicely on launch day.

There is no book that will hand hold you through the process "first do this, then do that" type of thing. There are many books that do explain the processes, calculations and principles necessary.

My suggestion is you offer some more detail into what you're attempting to do. If trying to design a ferro hull shell, then the first thing is a reasonable understanding of hydrodynamics and basic structural engineering. The book store on this site has many texts of these subjects, this may be a good place to start, but be warned, these are "easy" reads and you're not going to be designing a yacht by the end of the week. Jay Beniford has a very good book on ferro design considerations.

 

Continuing on from Paul's post

There are scanting and layup guides that were produced by both Class societies and Flag state authorities.
As far as I'm aware Class societies no longer publish scantlings for ferro cement. But you can find a lot of rules if you search. I know our (Australia) 'USL' covered ferro design and Lloyds Register was approving plans and supervising construction at one stage here.

I'd have some engineering material too that I could scan and email to you.

But I'd have to ask; these days with such good paint systems for steel why Ferro ?

 

Here's an example of hull layup, this is from 'USL'.
All class rules are/were very similar. It's a good indication and enough to show how much steel is actually in there since the matrix exhibits brittle failure under very low tensile stress.

 

Mike, I think the real issue here is if the original poster is capable of understanding the engineering dynamics involved, not to mention the hydrostatic elements. I'd be cautious about posting scantling generalities or averages, even if class specific. With the thought they might be the very bone they get up and run with, forgoing the realities of the engineering involved, which can be considerable in a ferro build.

 

Hi Paul,
I could point him at some scantlings that would be idiot proof. I can also give him some first principles engineering material but he's need to talk the talk to understand them

As I've said before I had a ferro ketch years ago. It's now on the bottom after bumping into Australia (under later ownership). Relevant to this thread the engine beds built to approved scantlings disintegrated after a few years under load and vibration.

But it isn't very sensible to build in Ferro these days the finished hull has zero value and is crippling in time to build. That should be enough to put anyone off !

 

It doesn't appear to be putting Tugboat off...... but then again I'll believe he's done it when I see the finished hull and not a second before.

PDW