Re: [PSUBS-MAILIST] Alternative hull material.

[Ward Monroe <wardomon@minn.net>]

The originals dive depth is around 3 1/2 feet. My modification would
bottom out at around 8.  Though certainly strong enough to withstand the
awesome crushing force at that depth and widely available, the 55 gallon
drum has few other redeeming values.  Most obvious is it's bluntness. 
Streamlining domes notwithstanding, the ridges would add battery
draining parasitic drag.  

Please correct me if I'm wrong, but isn't 33 feet 1 atmosphere?  The
pressure at 8 feet is almost trivial.  "Chopper gun" fiberglass can
withstand the rigors of the offshore environment for many years, so
would seem to be sufficiently durable for the calm of inland lakes.



On Mon, 2003-03-17 at 15:48, Coalbunny wrote:
> All depends on what you make it out of, what you intend to do with it
> and how long you want it to last.  You could build a sub out of wood,
> but the materials you use will restrict both applications and attainable
> depth.  Of course, if you are looking for a one way trip, a 55 gallon
> steel drum would work nicely....  :)
> Carl
> 
> 
> Ward Monroe wrote:
> > 
> > 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
> > > it gives to a question of yours, or the question it asks you, forcing
> > > you to answer, like Thebes through the mouth of the Sphinx." -- Kublai
> > > Khan
> 
> -- 
> "You delight not in a city's seven or seventy wonders, but in an answer
> it gives to a question of yours, or the question it asks you, forcing
> you to answer, like Thebes through the mouth of the Sphinx." -- Kublai
> Khan