Re: [PSUBS-MAILIST] Pressure Hulls

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

On Mon, 1 Jul 2002 10:25:44 -0700 (PDT)
Dewey Mason <drmason2001@yahoo.com> wrote:

> Hey All,
>   I assure you I think highly of you all, HOWEVER,,,,
> I will double check ALL math on my sub, I promise. Not
> that I don't belive you, just that I don't breath
> water, and feel no desire to be smooshed inside a
> steel ball. Sounds unpleasant.So you need not worry
> that I will kill myself and then blame you.

That's great, but still, lot's of warnings are useful
since many people are going to read this stuff
in the archives without context or a strong background
in what is right or wrong in this area.

> As to the
> exact specs for this metal, I am going to try to find
> out more today. I am thinking that if I have it tested
> for micro damage, then calculate the unreinforced
> depth, and use that number even after I DO add
> framing, then I wont die. I will also do several
> UN-manned pressure tests first.

Maybe consider destroying one of the spheres so
you know the failure mode and crush depth.    

>    Does anyone have any data on Stainless alloys?

There are some stainless steel specs at the bottom
of this page:
http://www.pic-design.com/tech/gear_calc/gear_calc.htm

303 Stainless Steel = 30,000Psi
17-4 PH Stainless Steel (Cond. H900) = 170,000

>  As
> to windows, who needs'um? They are BIG holes in the
> boat, and don't work well with a double hull design.
> Cameras can see in more directions, and safer. This
> critter is going to be a big ROV, with a little man
> living inside at the end of the cable. Or in this
> case, a rather large man living inside. It's purpose
> is to find, and to work. Not a sight seer. I have not
> yet found any formulas for computing reinforcement
> strengths. Anybody know how to do this? Where to find
> such? Which books are better?

Dewey, the American Bureau of Shipping's "Rules for
Building and classing: Underwater vehicles, systems
and hyberbaric facilities." have the formulas you are
looking for, it costs $75, it's not a big book, but
worth it.

Ian.
-- 
The moon ate the sun on Monday and it was an awsome sight to see.