Re: [PSUBS-MAILIST] In my search for a simple, cheap pressure hull ...

[Ian Roxborough <irox@ix.netcom.com>]

On Wed, 07 Nov 2001 12:52:37 +0000
"Eliezer Rodriguez" <eliezer_rodriguez@hotmail.com> wrote:

> Hi;
> 
> Why not use fiberglass combined with oak or marine plywood using the 
> sandwicich method? As I understand the sandwich method provides more 
> strength and flexibility. I got a couple of books about the subject but I 
> haven't been able to find them, which has more info about the process.

Plywood and GRP might work well for an ambient submarine, but
I think they are a number of issues to be addressed:

1) how is it going to perform under pressure?  Wood is kind of
porious which seems not too dissimilar to having air bubbles in
your lay up.

2) how do you predict the collapse depth?

3) Doesn't shaping all that wood add extra work to the
pressure hull construction?  More so if you are constructing
a spherical pressure vessel.

> I  also heard that even the goverment is experimenting with a special 
> fiberglass for submarines which is comparable with titanium.

Yeah, they are.  Instead of using glass they use Alumina fibre,
this produces some pretty tough pressure hulls.  The compressive
yeild strength is around 3000MPa, compared to 1200MPa for fiberglass,
550MPa for reguallar submarine steel (HY80) and 827MPa for
titanium alloy. 

Cheers,

  Ian.



-- 
Stop killing everything.