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