Re: [PSUBS-MAILIST] Alternative hull material.

[Ward Monroe <wardomon@minn.net>]

Being the lurker and newbie that I am, at what submersion depth does
consensus and research dictate a steel pressure hull?  For more than 20
years I've had in mind a modification to the Robert Riley AquaSub that
would more than double its diving depth.  I should probably build it
before I'm too old to ride in it...

On Mon, 2003-03-17 at 02:20, Coalbunny wrote:
> What I feel is overlooked is that water is worse than air- if there is
> ANYWHERE that water *might* go, it'll go there.  Under higher than
> normal pressures, such as going under water, it WILL go anywhere it can
> fit.  A cloth/kevlar sub hull *might* work for down to 10 or even 15
> feet.  And that's it.  It will be nearly impossible, I feel for it to go
> any further without a serious risk of implosion/rupture.
> My 6,000 rubles worth,
> Carl
> 
> 
> Tim Reilly wrote:
> > 
> > I agree with Mike that a kevlar hull would be great, except that kevlar is
> > really hard to work with and where ever you cut or grind it needs to be
> > sealed very well.  Kevlar likes to leech along the fabric.  You would also
> > need to make sure that the resin you use will be compatible with building a
> > hull that compresses and expands.  Some resins are to brittle and will
> > craze.  This will leave little cracks in the hull and allow water to
> > delaminate the material.  Something that might want to be considered is
> > alternating different materials with the kevlar to make it easier to work
> > with.
> > 
> > I intend on building my sub out of composite materials.  I also have a lot
> > of experience with these materials, the only thing is I don't know any of
> > the engineering stats for different kinds of materials to determine hull
> > thickness.  I am still researching that.
> > 
> > Sorry about making this so long, I just finally found something that I can
> > talk knowledgeably about.  Hope this helps.  Also realize that composites
> > are really easy to work with,  You just have to pay extreme attention to
> > what you are doing when you laminate.  NO AIR BUBBLES!
> > 
> > Thanks,
> > 
> > Tim R.
> > 
> > -----Original Message-----
> > From: Michael B Holt [mailto:tlohm@juno.com]
> > Sent: Sunday, March 16, 2003 8:52 AM
> > To: personal_submersibles@psubs.org
> > Subject: [PSUBS-MAILIST] Alternative hull material.
> > 
> > Consider a fabric hull.
> > 
> > Build the frames of the proper steel, then cover the frame with kevlar
> > cloth.   As long as the cloth is held securely to the frame, it's not
> > going
> > to rupture.
> > 
> > No, I'm not going to do this.    But it seems like a reasonable idea, if
> > all the problems can be solved.
> > 
> > Mike H.
> > 
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> -- 
> "You delight not in a city's seven or seventy wonders, but in an answer
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