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RE: [PSUBS-MAILIST] Welder with Vision

Rob,
Have you considered a composite? Either FRP over or
under steel, or a metal outer, monolithic concrete
inner hull structure? Even a multi-faceted hemisphere
would be stronger than a cone, I would think. With as
many as 20-30 plates. Like the tops of grain silos are
done. I have a friend in materials design at NASA, and
he and I have discussed the possible merits of a metal
outer, from lighter gage steel or aluminum, with an
injected plastic liner, say 1-2" thick. The
possibilities are many, and different hull materials
might be easier to work with and considerably stronger
than steel. 
Dewey
--- robertbatta@comcast.net wrote:
> Alec,
> 
> Exactly what I was looking for - thank you for your
> insight. 
> 
> Rob
>  
> > Rob,
> > 
> > When you think of basic shapes applied to pressure
> vessels, what you
> > might call a "desirability rating" in
> best-to-worst sequence is as
> > follows:
> > 
> > 1) Sphere
> > 2) Cylinder
> > 3) Cone
> > 4) Flat surface
> > 
> > That is, a sphere is more efficient than a
> cylinder, etc. Things like
> > elliptical cylinders or elliptical endcaps would
> fall somewhere in
> > between. Of course you see all sorts of flat
> surfaces or odd shapes on
> > submarines from the outside, but I'm talking of
> the pressure hull
> > proper, on 1 ATM boats.
> > 
> > So I have two suggestions:
> > 
> > For the endcaps, the ideal would be hemispheres
> instead of "flatter"
> > cones. However if you find hemispheres of the
> desired measurements to be
> > non-standard and thus expensive (this happened to
> me), then try for
> > elliptical endcaps, which are still a better
> approximation to a
> > hemisphere than a cone is.
> > 
> > Second, you might consider two vertical cylinders
> for the coning tower
> > instead of a half pipe. The reason spheres and
> cylinders are efficient
> > at resisting pressure is because the forces
> created on the surfaces are
> > evenly distributed. There must be a more elegant
> way to put it, but if
> > you think of a sphere, the force on any point has
> an identical opposing
> > force on the opposite side. This is true of a
> cylinder too, but it is
> > NOT true of a half pipe. Plus, with the half pipe
> you have the challenge
> > of closing the ends, and especially of providing a
> hatch seat, in what
> > would be a curved surface. That is if you're
> planning a hatch on top of
> > the coning tower.
> > 
> > Hope that helps, and I apologize in advance if
> I've stated things that
> > might be too obvious.
> > 
> > Thanks,
> > 
> > Alec
> > 
> > 
> > -----Original Message-----
> > From: robertbatta@comcast.net
> [mailto:robertbatta@comcast.net] 
> > Sent: Tuesday, December 30, 2003 4:45 PM
> > To: personal_submersibles@psubs.org
> > Subject: Re: [PSUBS-MAILIST] Welder with Vision
> > 
> > Thijs,
> > 
> > That is the design I had in mind.  My last sub was
> a single occupant in
> > the prone position, I am looking to "upgrade".
> > 
> > I realize the design is complex, Im hoping to get
> feed back from you all
> > on this.  To answer your question, yes, this is
> the design I had in
> > mind, two occupants, one in front of the other. 
> > 
> > Thanks,
> > 
> > Rob
> > 
> > > Rob,
> > > 
> > > What you discribe makes me think of a Perry
> Cubmarine (If you don't
> > know
> > > what that looks like have a Google image search
> for "PERRY
> > CUBMARINE".) A
> > > design like that gives you the opportunity to
> have 2 people sitting
> > upright
> > > in a small sub. I fear that it is complicated to
> design (stresses!)
> > and
> > > build. Is this the concept you have in mind?
> > > 
> > > Geatings,
> > > Thijs Struijs
> > > The Netherlands
> > > ----- Original Message -----
> > > From: <robertbatta@comcast.net>
> > > To: <personal_submersibles@psubs.org>
> > > Cc: "Carsten Standfuss" <MerlinSub@t-online.de>;
> > > <personal_submersibles@psubs.org>
> > > Sent: Tuesday, December 30, 2003 8:59 PM
> > > Subject: Re: [PSUBS-MAILIST] Welder with Vision
> > > 
> > > 
> > > > Not as of yet, I will send them when complete,
> I may even hand draw
> > > something to get my questions answered.  I am in
> the process of moving
> > from
> > > one home to another, once settled in, I plan on
> building a cardboard
> > mock up
> > > to nail down the measurements.  The pressure
> hull is nothing more than
> > a
> > > pipe with end caps (30 or 45 Degree Cones), the
> pilot and passenger
> > are in
> > > the sitting position, their upper bodies and
> head are in the conning
> > tower.
> > > >
> > > > For the conning tower, I plan to cut in half a
> length of pipe
> > (smaller
> > > diameter), and mate it to the main pressure hull
> - am I making sense ?
> > > >
> > > > I plan on using pipe flanges for view ports -
> here's my question:
> > With
> > > the forward end cap on the conning tower ( that
> is cut in half or
> > shaped to
> > > match the surface of the pressure hull ) can I
> mate a pipe flange to
> > that -
> > > given all the angles ?  Am I asking for a
> fabrication nightmare ?
> > > >
> > > > Again, my little knowledge of metal works -
> The end cap is already
> > coned
> > > and cut to match the pressure hull, is it
> feasible to cut a hole in it
> > to
> > > accept the pipe flange for a forward view port ?
> > > >
> > > > Please keep in mind, this is conceptual, I
> appreciate constructive
> > > criticism.
> > > >
> > > > Thanks in advance.
> > > >
> > > > Rob
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > > Is a DWG or DXF file available ?
> > > > > Or a scan of the drawing as JPG ?
> > > > > What kind of questions about the welds ?
> > > > >
> > > > > regards Carsten (Naval Architect)
> > > > >
> > > > > irox schrieb:
> > > > > >
> > > > > > Hi Rob,
> > > > > >
> > > > > > unforunately I can't recommend anybody to
> review your design,
> > but I do
> > > > > > hold some of your concerns.   Mainly -
> will people think we are
> > nuts
> > > when
> > > > > > we ask professionals to review our
> designs?
> > > > > >
> > > > > > Has anybody had/hired a professional
> engineer (in the
> 
=== message truncated ===


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