Re: [PSUBS-MAILIST] Re: Variable Ballast Calculations, Bill

[Paul Kreemer <paulkreemer@gmail.com>]

Thanks Bill for the great explanations.  I like those ideas - both
work creatively with underwater physics and physiology.  How about
'regenerative ballasting' for a term?   You'd expect a hybrid
ambient sub would need some sort of regenerative system, like any other
hybrid vehicle.  :-)

It sounds good to me to limit cabin pressure to two atm total.  I
don't have my old PADI dive tables with me but it looks like the Navy
tables give 310 minutes no deco time at 35 feet.
http://home.flash.net/~table/table/p0000149.htm
That seems like a very useful dive time, considering that you're in a
relatively warm and dry compartment.  And very different from the
15 minutes of bottom time that these same tables give for 120 ft. 
Of course a person would probably use a dive computer or other tables
and get some different numbers.


Would you guys say that a hybrid ambient would be a little more
complicated, or just different, to design and operate than either a
pure 1atm or a plain ambient dry sub?  The ballast tanks are
plumbed into the crew compartment and so could allow water to
enter.  Dan notes that the cabin would need to resist an internal
overpressure (or have a good overpressure valve?).  And I'd think
that the hull would have to be strong enough to handle the max
operating depth with a cabin pressure of just 1atm.



Paul