Re: [PSUBS-MAILIST] Brass vs. Bronze

[Rob Ossian <rob_neptune@yahoo.com>]

Actually what separates flesh from fish on Hawke's
Deep flight 1 is four inches of fiberglass hull. A
staff of engineers and volunteers wound it in a
continuous monofilament wrap around a 26-inch-diameter
cylindrical mandrel.  

Pretty nifty thing to watch the thing slowly spin
around like an old Ediphone record maker...
 
--- Andy Jensen <drewacard@charter.net> wrote:

> Bill it is not a crazy idea Deep Flight 502 was cast
> of Al i think it is like an  inch and a half thick
> only fits one person per pod. but it has been done.
> Andy J.
> 
> ---- Akins <lakins1@tampabay.rr.com> wrote: 
> Hi Sean.
> 
> You make a lot of sense and good points. Oh well, it
> was just a conceptual idea anyway.
> I guess if it was a good method to use, it would
> already be in use. Just another crazy idea of mine.
> Bill Akins.
> 
> 
>   ----- Original Message ----- 
>   From: Sean T. Stevenson 
>   To: personal_submersibles@psubs.org 
>   Sent: Tuesday, April 11, 2006 5:36 PM
>   Subject: Re: [PSUBS-MAILIST] Brass vs. Bronze
> 
> 
>   While certainly possible, I think that there are a
> few practical 
>   limitations to casting a submarine hull.  The
> obvious one is size - you 
>   need to cast the entire thing in one continuous
> pour, necessitating a 
>   foundry with that melt capacity.  The second is
> quality control - 
>   porosity is much more difficult to avoid in
> casting than it is in weld 
>   beads - once cast, every square inch of the hull
> would need to be 
>   examined through non-destructive testing (x-ray,
> ultrasound, etc.), as 
>   opposed to just weld seams, and then if you do
> find a problem, you may 
>   have to scrap the whole thing and re-cast if it is
> not in an area that 
>   is easily patchable.  The third is dimensional
> control - save for the 
>   ideal case where you cast a perfect cylinder with
> no hull penetrations, 
>   bosses, stiffeners, etc., variable cooling rates
> due to material 
>   distribution within the cast will cause the
> finished casting to deviate 
>   from the original pattern.  Ordinarily, foundries
> will account for this 
>   by modifying the pattern to compensate
> (guesstimating), or by working 
>   the finished castings in presses, etc. to bump
> them back into 
>   compliance.  For commonly cast parts like pump
> housings, etc., this is 
>   no big deal, but pressure vessels are somewhat
> more dependent on their 
>   geometry for proper function.  This is not to say
> that it couldn't be 
>   done, but my gut instinct is that it would be cost
> prohibitive, as well 
>   as a lot of work.
> 
>   -Sean
> 
> 
> 
>
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