PVC or closed cell composites?

[58ketch]

I'm just wondering...has anyone used or experimented with PVC as hull material? How about composite dimensional lumber?

It NEVER rots.

It is fully malleable.

It comes in sheets and/ or planks that are dimensionally stable and consistent.

It is "weldable" , glueable and screwable...and HIGHLY impact resistant.

It would seem, aside from the addition framing required, almost a "natural" for hull construction.

Anyone?

[gonzo]

They make all kinds of kayaks and dinghies and other small boats.

[58ketch]

Yes, I am aware of that. I was wondering if anyone had heard of or used these alternative materials in larger scale products where structural integrity is a priority.

[Commuter Boats]

Your biggest problems will be weight and creep, the weight is tolerable in a Roto molded structure as all of the stiffeners are molded in with much of the stiffness coming from a compound shape. In a more conventional build the weight of structure would likely push the material into its plastic zone and creep (slowly deform) would impact cosmetics and performance.
I've seen a 7.5 x 4' pram welded from 1/4 inch PVC and to suggest that it was an ugly duckling would be kind, it was also heavy and at present only one year old so durability has not yet been confirmed.

[springerdw]

You were referring to the cellular PVC type of building material. Right?

Here's a place making them now...
http://www.rionholdt.com/HOME%20PAGE.html

Any thoughts??

Thanks,
Dave

[rwatson]

Have you read this article ?

http://www.boatdesign.net/articles/foam-core/index.htm

I found it usefull

[58ketch]

Excellent article.

As it happens, it is my work on a '58 Dickerson ketch (a modified bugeye) that got me to wondering about this. She is plank on frame bronze fastened and I could easily see this being "re-engineered" with a composite material like PVC sheet-goods.

The Rheinholds are doing pretty much what I am asking and on a similar hull type....guess its time to pay them a visit...thanks for the link!

Here is my current project and "intellectual springboard"...



and a view of her bottom prior to replanking/seaming...



As she was/is built entirely of mahogany which is both expensive and subject to deterioration AND the planks happen to net exactly 1" I could but wonder if the same grace and beauty could not be had with another more "permanent" material....seems it can, in fact.

Now, how's this work and how's it working out in terms of cost,lifespan, structural integrity and ease of application?

[Eric+Annie]

Hello ~
Ran across your post on the boat design discussion list / PVC thread that you posted back in September 2009.
We are the "Rionholdt" people. You mentioned that it may be time to pay us a visit. We love to "talk boats", especially deadrises - whether wood or plastic.
We've lots of experience with the type and are steeped in the tradition. Feel free to give us a call at 804-338-5856.
Eric
www.rionholdt.com

[58ketch]

Well, thank you, Eric and Annie Rhienhold...I've been quite interested in the work ya'll are doing and will surely get in touch soon..a visit would be wonderful!

The good news is that after a long hot summer of shrinking and re-seaming our Dickerson now floats in her slip on her own (bilge pumps keeping up easily). We have identified what we THINK is the last major leak and will address that in the spring along with a myriad of other tasks that are considerably less daunting than those we addressed last summer.

The entire issue of composites is still out there for consideration, however.

Thank you again for your interest and response. I hope to be able to pay ya'll a visit soon!

[springerdw]

58Ketch,

Did you ever get a chance to pay the Rionholdt's a visit? I see they have new hull.

Dave