Re: [PSUBS-MAILIST] concept query

[Phil Nuytten <72020.572@compuserve.com>]

Hi, Joe:
        Nope, Dan's proposal is not similar to ring stiffening . .Dan
proposes a series of concentric hulls with between-hull pressurization, in
the hope that the internal pressures will add (on a 1:1 ratio) to the
hull's ability to withstand external pressure. That is, if the monohull
could tolerate, say, 150 psi - then pressurizing it to 50 psi, internally,
would allow it to tolerate 200psi externally, and so on. The only way that
the external or outer hull can 'see' the additional 50 psi, is if it begins
to yield or become 'plastic', 
The extra 50 psi will increase the pressure at which the outer hull yields,
but only at the cost of having an extra 50 psi on the external portion of
the next hull.  - No free lunch. The hulls will transmit pressure freely
only if they are made of a soft, deformable, material. Otherwise, they will
resist until they can resist no more . .then they will turn into
'deformable material' and transmit big-time!! This is termed 'catastrophic
failure'  . .or in the biz." a f-ckin' disastrophe !! "
        Again, I say:  Whatever depth you can achieve by multiple hulls,
with pressure between, is the same or less than that achievable with a
single hull of the combined thickness -( for a given one-atmosphere
internal volume)
        And, speaking of disastrophe's . .I was BS'ing with Bill Meistrell
( Meistrell brothers, owners of 'Body-Glove') - he is an old subslut . .
.operated 'Sea Snooper' for years . .last week at the NOGI awards banquet.
He told me that  they had recently built a deepwater sub and didn't want to
go the expense and hassle of strain guaging, controlled chamber
pressurization, etc.. so they lowered it into the sea to the calculated
test depth of 2800 feet. .whoops! instant halibut!! Darn those pesky
calculations! (G)
Phil Nuytten