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RE: [PSUBS-MAILIST] hull thickness technical help needed
David
I completely agree with Joe and I would suggest that the answers you
receive from this forum will sometimes conflict with what you may like
to hear.
When you receive advice like this just remember it's not a criticism
that is intended to dent your enthusiasm. Most often the opinions and
advice is supplied by eminently qualified people with some amazing
backgrounds and lots of first rate hands on experience.
My own projects design has changed and been modified countless times and
fabrication delayed by at least 18 months as a result of the education I
have received from members of this forum. I want a functional Psub not a
white elephant.
I agree with Joe when he says:
"It is the intention of this forum to promote safely operated and
successful Psubs. Be prepared to receive feedback that you may not be
expecting nor desire to hear. This is a veritable gold mine but, you
have to learn to mine it."
Find a few senior members; take the time to get to know them, their
backgrounds and qualifications then see if a few who have the time will
mentor you through the process.
Regards and best of luck
Steve P
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Joseph
Perkel
Sent: Thursday, 19 October 2006 10:46 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] hull thickness technical help needed
David, (I think, you don't sign your posts)
No heartbreak here, I happen to love composites...there's a little
outfit
out in Mojave California, (Scaled Composites I believe :), that's been
doing
some pretty amazing things for awhile now. In fact, they'e been
showcasing
for decades now composites absolute best feature.......it's super high
strength to weight ratio.
What if you could build a composite 1 atm sub hull that could submerge
50 cf
to 1000 m, and the shell itself would weigh a mere pound.
Would you still require 3,200 lbs of weight to reach neutral buoyancy?
What
would this weight consist of? I don't believe good ole Archimedes there
will
let us get away with that so fast.
So composites is ruled out as a favorable material for 1 atm
submersibles by
simple physics is it not?
If you are to pursue a 1 atm submersible hull utilizing composites, you
must
do so by acknowledging and accepting the responsibilities and pitfalls
of
experimentation with the budget and resources of an individual.
Personally....me copy what been done already! :)
It is the intention of this forum to promote safely operated and
successful
psubs. Be prepared to receive feedback that you may not be expecting nor
desire to hear. This is a veritable gold mine but, you have to learn to
mine
it.
Best of luck to you
Joe
>From: DrewBane1@aol.com
>Reply-To: personal_submersibles@psubs.org
>To: personal_submersibles@psubs.org
>Subject: Re: [PSUBS-MAILIST] hull thickness technical help needed
>Date: Wed, 18 Oct 2006 16:23:42 EDT
>
>Hate to be a heart breaker but might be onto the information im looking
>for.
>Been talking to the engineers at work and one of which has a clue as to
>where i might find the design specs
>on a vacuum chamber they designed a few years back and the technical
info
>to
>be able to calculate hull thickness. As far as repairing frp and
weeping
>hulls, this sounds more like a poor construction using old polyester
resins
>not
>the epoxy vinyl ester that is commonly used on todays pressure vessels.
OK
>here is some insight on frp pipe, 24" dia. 3/4" wall frp pipe is rated
for
>100
>psi internal pressure, test pressure is 150 psi, max test pressure is
225
>psi.
>There is a 10 x's safety margin on the pipe pressure and DOW claims
their
>resins achieve a 16 x's safety margin and yes they do take into
>consideration
>constant pulsing and hammering of the pipe as well as temps of 180' and
>chemicals that would eat your steel subs alive. (no offense to steel
>lovers) For
>those that think frp will give them greater styling advantages, this
is
>only
>true for ambient subs shape will still play an important role on a 1
ATM
>sub
>in frp. When i get the information for calculating thickness for a
vacuum
>chamber I will share it freely with those that love composites.....
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603-529-1100
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