Re: [PSUBS-MAILIST] Alternative hull material.

[Ward Monroe <wardomon@minn.net>]

Thanks for the clarification.  My bad.  I should have said "1 atmosphere
over ambient" to be more precise.  As a kid I used to free dive with
mask and fins to 10 feet all the time.  It's a pretty good squeeze, but
not a real problem.  I would think that the strength, formability,
durability, life span and hydrophobic qualities of fiberglass would be a
safe material for the rather benign conditions at 8 feet.  And surely
catastrophic compressive failure would not be an issue for a properly
constructed shape.  Seeing as weight is good, an overly thick hull
should easily handle the stresses.

Thanks for everyones comments.  Back to lurking...  

On Mon, 2003-03-17 at 06:06, peter mckellar wrote:
> Hi Ward,
> 
> >Please correct me if I'm wrong, but isn't 33 feet 1 atmosphere?  The
> pressure at 8 feet is almost trivial. 
> 
> 0'  = 1 ATM
> 1 ATM = 14.7 psi
> 33' = 2 ATM (2 ATM is actually 32.8')
> 8'  = 2.5m
>     = 1.25 ATM
>     = 18.4 psi (true, pretty trivial)
> 
> i've rounded a little in the sums :)
> 
> 14.7 psi seems higher than my faded pre-metric memories suggest.  can anyone confirm this is correct?
> 
> the conversions were done by:
> 
>   http://www.megaconverter.com/Mega2/
> 
> 
> hope this helps
> peter