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Thank you Stewart
for your reply again I say to you as I did to Alan a New Zealander who
also answered my email, sorry for the delayed reply been distracted for a
while.
Yes it is the dream but as they say, not to
dream is to die ,at least on the inside anyway.
Respect and appreciate your comments and have taken
them on board. However as weight is a major concern for my requirements I
will still have that as my major criteria if possible.
By the way the sub pressure testing requirements
bothers me a little ..can you direct me where I might obtain some written
data on this.
I am all for maximum safety it is the major
precursor to all my design.........but I have incorporated at least
three back up systems for preventing slipping any deeper than 300 feet,
including auto surfacing beyond 320 feet as a safety factor. With this on
board the 3 times pressure factor seems over engineered.This I would
consider precludes a three times safety factor
By the way I think I read in the Stachiw
book a seven times factor for acrylic domes and windows?
Now my logic indicates to me that either they
should be both the same either way because the lesser will fail anyway so the
maximum is obsolete???
Appreciate the links and will follow up accordingly
...drat, more reading and learning ..this sub stuffs a full house isn't
it?
Thanks again
Cheers
Les
PS The reply from Alan James in N.Z
.was interesting, you may be interested to read...don't know if you also
received it? (just new at this sharing system)
PPS By the way where are you?, I am in Adelaide
S.A.
----- Original Message -----
Sent: Wednesday, February 24, 2010 7:23
PM
Subject: RE: [PSUBS-MAILIST] New Guy from
down under needs help
Hi Les! Greetings
from a fellow aussie J A light weight sub
is every person?s dream? But as you can probably tell it hasn?t been done much
before and to build a composite submarine in Australia is
going to be very very expensive if not impossible, you need an autoclave and
plug big enough to fit your sub in, or you build it out of smaller sections
and join them, which causes other problems.
Also your
talking about wanting to go to a maximum of 300 feet right? But you have to
over build your sub to ensure it is strong enough! Someone correct me if im
wrong but I thought most sub?s were pressure tested to 3 times their expected
max operating depth as part of their certification????
Also there is only
one mode of failure with a composite pressure vessel? and I would imagine with
150psi pressing in from around you wouldn?t get much warning if something was
wrong with it other than a pop or crack and then nothing? because you would be
dead?
Here are some links I
found, The military and universities have been toying with composite sub parts
and hulls but I think for now your best bet would be to stick with steel or
aluminum.. Composite air and hydrogen tanks sound/look like a good candidate
but I don?t think I would trust their reliability, and pressure from the
inside is different to pressure pressing in from the outside, Most of the
carbon/Kevlar tanks are spun formed over a mold/plug which is then heated and
pressure is put on..
http://www.ericgreeneassociates.com/images/History_of_Submarine_Composites.pdf
- History of Submarine Composites
http://www.bac.net.au/submarine.html
- An australian company that makes composite parts for the Collins class
submarines though they are not pressure
vessel?s..
http://composite.about.com/library/weekly/aa990217.htm
- X-33 Composite Tank Problems,
Complex shaped hydrogen tanks. Shows why composite materials are so difficult
to use for mission critical applications and pressure vessels..
http://www.ctd-materials.com/products/tanks.htm
- Company that manufactures small composite pressure vessels, also lots of
pictures which give you an idea?
http://www.pentairwatertreatment.com/PentairFiles/Pentair%20Water%20Treatment/Literature/Composite%20Tank%20Sell%20Sheet%2042575.pdf
? Composite pressure vessels, some rated to
150psi
An example of one of
their largest tanks?
Opening : 16" 6?
operating pressure :
150psi/10.34bar
Height : 3695.7mm
Diameter : 1638.3
Capacity: 6057 Litres
Weight:
634kg
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Les & Anna
Sent: Wednesday, 24 February 2010 5:58
PM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] New Guy from
down under needs help
My name is Les, in Australia, I
joined psubs almost a year ago,after much much reading, and
learning, an experience I am sure that you are all aware, I do have
a couple of questions that some-one may be able to assist me
with.
My aim is a specialized maximum
depth 300feet 1atm sub, of which weight is most critical, therefore I am
considering the exotics such as carbon fibre and
Kevlar
.
1. Any experienced
knowledge on these two materials re this pressure 150psi that anyone can
give me would be most appreciated.
2. Any information
regarding acrylic bubbles or more precise half bubble or dome 4 feet (1200mm)
to 6 feet (1800mm)diameter for this depth and pressure, would also be
Looking forward to learning more
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