RE: [PSUBS-MAILIST] Welder with Vision

["Alec Smyth" <Asmyth@changepoint.com>]

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
appropriate
> field) to
> > > > review your submarine designs?  Was it hard finding somebody
willing
> to review
> > > > them?  What where the reactions you where getting from people?
> > > >
> > > > Also how much did it cost to have the design reviewed
professionally?
> > > >
> > > > Thanks,
> > > >   Ian.
> > > >
> > > > -----Original Message-----
> > > > From: robertbatta@comcast.net
> > > > Sent: Dec 29, 2003 2:09 PM
> > > > To: personal_submersibles@psubs.org
> > > > Subject: [PSUBS-MAILIST] Welder with Vision
> > > >
> > > > Hello all,
> > > >
> > > > Hope everyones holidays are going well.  Here is my question, I
am
> nearing the
> > > end of hull design for my 1ATM two man sub.  The next steps are to
> consult a
> > > welder to iron out the details.  Do to my lack of knowledge in
steel
> > > fabrication, I would like a welder - the one doing the work - to
look at
> my
> > > drafting and make modification suggestions if necessary.  For all
I
> know, I
> > > could be asking for some angel that would require tremendous
fabrication
> effort,
> > > and could be done another way.
> > > >
> > > > Does anyone know a welder in New Jersey or PA that wouldnt think
I am
> out of
> > > my mind for building a sub ? ? ?
> > > >
> > > > Thanks in advance.
> > > >
> > > > Rob
> > > >
> > >
> >
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