Re: Subs

[Rick Lucertini <nexus@intergate.bc.ca>]

Ray Keefer wrote:

> Hi Charlie,
>
> > Dear Ray:
> >
> > Can you please send some more info on the propane Tank sub!!!!!!!!
> > Is there a set of plans out there????
> >
> > I would like to construct a sub.  Please get back to me!!!
> > My name is Charlie.
> >
> > THANNKS SOOOOOO MUCH!!!!!
> At first look using propane tanks look like a good idea, but consider you
> don't know the metalurgy of the metal or the stresses already imposed on the
> metal during the life of the tank. So you should derate your depth consideribly
> and do unmanned testing before trusting your life with it.
>
> Actually I asked George Kittredge about propane tanks when I visited him. I
> don't remember his exact words but he was very adament that it was an
> unsafe approach. My view is that with the proper caution it will work,
> just don't push it.
>
> Regards,
> Ray

I'd like to ditto what Ray and Cdr. Kittredge cautioned: derate and proceed with
caution.  A propane tank is intended to keep pressure in, not out.  [I'm assuming
you're thinking of a one atm. boat].  Metal under tensile stresses behaves
differently than when  under compression.  Metal has great tensile strength.  But,
under pressure, a cylinder would certainly require mucho framework to keep it from
caving in.

Rick Lucertini
Vancouver, Canada