Tortured plywood designs

[rwatson]

Originally Posted by apex1

Sorry rw wrong (as usual),

Arrogance is cheap ! or are you just hungover when you go online?

Originally Posted by apex1

what has foam in common with tortured ply? Exact! Nothing.

It is an excellent substiture, thats what! Perhaps you would like to look up the number of commercial builders in Plywood V Foam in the world. With thin foam, I can get curves that would snap any plywood, If I groove thicker foam, I get an equivalent shape with a lot less work.

Originally Posted by apex1

There is very high quality ply at the market, at reasonable prices. Foam is not available at reasonable prices.

Yes, there is also a lot of real rubbish as the last 12 months of comments will tell you. I daresay you pay similar rates in EU, we are having $AU120 per sheet. The comparable panel in foam and glass is about 20% dearer, doesnt rot and is a way lot lighter.

Originally Posted by apex1

And a epoxy layup will hold as good on ply as on foam (in some cases even better).

Did I say it wouldnt????

On foam ,you dont need to use expensive and unhealthy epoxy. Vinylester will save money and do a great job

[apex1]

Originally Posted by rwatson

Arrogance is cheap ! or are you just hungover when you go online?

May I send this back? (unused of course)


It is an excellent substiture, thats what! Perhaps you would like to look up the number of commercial builders in Plywood V Foam in the world.

Rw you should try to understand what "tortured ply" as a building method means! You would soon notice, that your statement is silly.

I build in both materials rw, believe me, epoxy is the better choice on ply. And foam, as mentioned above, has nothing to do with the building method! Tortured ply is what the name says "plywood", not steel, aluminium or foam and glass, no, just ply!
Tortured, of course......................................

Regards
Richard

[szkutnik]

Originally Posted by apex1

wrong (as usual),
Regards
Richard

This is not fair!
It cost nothing to say sorry.

[gonzo]

I don't think foam would create the stresses to be tortured like plywood. It may bend more, but that defeats the purpose.

[apex1]

Marek
one says sorry when one feels sorry, or was wrong, I was´nt.
You cannot make a "tortured plywood" structure using steel or glass. But TP was the thread topic, not foam and glass, or anything else.
Richard

[szkutnik]

Originally Posted by apex1

rw, believe me, epoxy is the better choice on ply.

Richard,you are wrong!You don't read carfully.
rwatson is right! He sed
-On foam ,you dont need to use expensive and unhealthy epoxy[/b]
Other words- Youhave to use epoxy on plywood.

But you Richard sed: epoxy is better choice on ply.
Many people will anderstand that vinylester or poliester are good on ply but epoxy is better.
In my and Rwatson opinion epoxy is only choice on ply.
In yours, just better choice.
IMHO you are wrong(should i sey -as usual-? No, i will not say that.
I just looked at two other threads and on both you was wrong.
I am afraid to read more.
But it doesn't mean that i can say :wrong ,as usual

[apex1]

Originally Posted by szkutnik

But you Richard sed: epoxy is better choice on ply.

Yes I said so, and that was correct.

You do´nt get it Marek.

First point,
we do NOT discuss FOAM, STEEL, GLASS, PAPER, LEATHER and ONION SKIN here!

The thread topic is "TORTURED PLYWOOD" that is a proven boatbuilding method. I thought you would know that, being a boatbuilder?
So, one cannot substitute plywood by any other material, there is no such building method as tortured foam, thats nonsense.

Second,
of course one COULD use polyester or vinylester on plywood, and the industry has done it for 50 years now.
Again, as a boatbuilder you should have known that.

So, after rw was wrong (or at least completely besides topic), now you are going to make his mistakes too.
He is a amateur and has every right to be wrong.
You claim to be a boatbuilder, you have no right to be completely off the track!

Regards
Richard

and please let me know where I was wrong on other threads....

[ancient kayaker]

Originally Posted by apex1

... and please let me know where I was wrong on other threads....

I hope they don't We need to get back to the original discussion, which was of interest to me at least.

Is there a measure for how much ply can be tortured, I wonder. It would have to factor in thickness, plank width, twist per unit length, and wood characteristics. Is it possible to quantify it? Free!Ship provides some data but I for one don't know how to interpret them.

[szkutnik]

Originally Posted by apex1

You claim to be a boatbuilder, you have no right to be completely off the track!

Regards
Richard

and please let me know where I was wrong on other threads....

Sorry ,but as a professional boat builder, i will not use other staff like poliester in tortured ply metod ,what you suggest.
IMHO epoxy is ONLY ONE good choice on tortured ply.
Thats all i sed. Is it completely off the track!
?

where wrong?
You sed - mat is just weight but has not much strength.

If mat is just weight, why thousands boats are not falling apart into pieces.

Using a fabric you can choose the direction of load transfer and build a lighter boat but in places without directional load mat is as good as fabric.
In my work i don't use mat, but not because "mat is just weight but has not much strength".
There are other important for me reasons.

The rest is just asking you to stop offend people.

Regards
Marek

[apex1]

Thank you szkutnik, for the very deep insight in your level of knowledge!

Now can we please return to the topic?


Terry
I do´nt have any data, and never built in TP method. Also I can not find how the Freeship data would help.

Regards
Richard

[ancient kayaker]

In post #3 I mentioned "new design with bottom planks that will each have a 85 deg twist from midships to the stems" which I have as a FreeShip model. The image shows the hull using the "developability" mode. In the plank developments the "edge error" reported by FreeShip varies from 0.0044 (0.44%) in the case of the garboard, shown mostly in warning red, to zero in the case of the upper planks shown in green.

FreeShip seems to show one edge error value only, the other edge is always zero. If it assumes no strain along one edge then perhaps half the displayed FreeShip value might be taken as the edge strain, in which case 0.22% is the highest number any of my designs have.

I have data for white oak, tension yield point 4,760 (psi) and modulus of elasticity 1,780,000, which would make the yield strain 0.27%. For white pine yield strain is 0.29%. The data for Okoume is from a different source, I have less confidence in it but it indicates yield strain of 0.35%.

I haven't built the new design yet, but I modelled the garboards. It seemed to me that the okoume ply was within its limit, no noises and it sprang back most of the way to flat when released. From the above data it would be at 63% using half the FreeShip edge error value and 126% using the full value.

[apex1]

Let me play with it.

[gonzo]

The way I look at tortured plywood, it where there is bend in both ways and maybe some edge set. I suppose a program would have to include data for the thickness and type of plywood. I have build and helped with kayaks and canoes. However, building a small model doesn't work well for this method as for simple developed shapes.

[nordvindcrew]

Check out Paul Gartsides' flash boat. It is a tortured plywood rowing boat. Extreme curves in the ends

[gonzo]

They produce some really pleasant shapes.