RE: Mathematics for sub desginers (beginners)

["Morrisson, Richard D" <Richard.Morrisson@PSS.Boeing.com>]

For water pressure at depth consider a box 1' by 1' by whatever tall.  The area on top of the box is therefore one square foot.  Water (sea) weighs about 64 pounds per cubic foot (fresh is about 62.4).  The top of the box must support the weight of (pressure due to) the water above it.  This weight is 64 times the depth in feet (the pounds per cubic foot times the height in feet).  Divide the resulting pounds per square foot by 144 to get psi.  It comes out to about .44psi per foot.   Hopefully you can follow the logic to this explanation and see the basis for the formula, which is generally more valuable than the formula itself.

> ----------
> From: 	sebastian.hunt@virgin.net[SMTP:sebastian.hunt@virgin.net] on behalf of Seb[SMTP:sebastian.hunt@virgin.net]
> Sent: 	Thursday, February 18, 1999 8:15 AM
> To: 	'personal_submersibles@psubs.org'
> Subject: 	Mathematics for sub desginers (beginners)
> 
> Hi. Can anyone tell me where I can find out the formulas that are important for submarine design? Starting quite simple, I still can't find the formula for water pressure at depth. I assume this would be elementary physics, but I must have missed that day at school! What about calculating thrust from a prop, given its dimensions/pitch/speed etc? My web searches have revealed nothing so far.
> 
> I'm also quite keen to track down information about human tolerances to variations in air pressure and gas mixtures and anything else that might pose a physical threat to a sub pilot.
> 
> Hope someone can point me in the right direction.
> 
> Cheers,
> 
> Seb Hunt
>