RE: [PSUBS-MAILIST] Re: "working" Disney(ish) Nautilus has a Propane Tank Hull.

[Jim Pesanka <jpesanka@yahoo.com>]

Hi everyone, and thanks for your replies so far.  Very helpful.

 

I've just learned that the Ebay sub has a modified propane tank for its pressure hull.  I believe there have been discussions about that very subject here before.  Is anyone willing to briefly outline the pros and cons of using a propane tank as the basic pressure hull for a psub?

 

Also, I'm interested in your discussion of oval shaped pressure hulls, especially since the tower on the Ebay sub is oval shaped, and sits on a large oval shaped hole in the propane tank hull.  Am I correct in assuming that might decrease hull strength against presssure?

 

And can anyone tell me what a fair price of a Kittredge K-250 submarine might be?  I've learned the Ebay sub takes much of it's design from the K-250.  The owner says similar subs sell for $100,000.00, and he is asking $45,000.00 for the Ebay sub.  Does that sound about right?

 

Thanks to everyone for the assistance.  This is a great place to get information about psubs. 

 

Jim

solomon D <solomondees@yahoo.com> wrote:

I can see what you mean about this ebay submarine. It
looks as if it was built mainly for looks with no real
intentions of it diving. There seems to be no kind of
internal bracing that a pressure hull should have. If
you added all the additional bracing, drive
system,controls and equipment needed to really dive
there wouldnt be any room left for a pilot. The view
ports seem to be an after thought just cut out and
bolted on. Who knows how well the welds were done? I
doubt that it is even water tight on the surface.


--- Alec Smyth wrote:

> I'm afraid I wouldn't touch it, sorry. Often people
> come up with ideas
> about subs that should look cool, like say a fighter
> plane or some Star
> Wars space craft. They then try to design something
> to match the
> particular look they have in mind. But I think subs
> should be designed
> in exactly the opposite way; the laws of physics and
> the limitations of
> materials dictate most decisions, and the appearance
> (unfortunately) is
> a bit of a by-product. This sub is an entirely
> aesthetics-driven design.
> Notice the endcaps made of flat plate wedges, for
> example? Those would
> surely concentrate stresses. I would worry that if
> someone's primary
> motivation is the "look" of a sub, they probably
> have not done any
> stress calculations, used appropriate materials,
> done full penetration
> welds, put just the right depth on an o-ring groove,
> etc., etc. The last
> thing you want in a submarine is to go etcetera
> hunting.
>
> It looks like it's nicely made, and may even dive
> safely to a few feet,
> but can anyone tell how many? I would not want to be
> the one to find
> out.
>
> :-(
>
> Alec
>
> -----Original Message-----
> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On
> Behalf Of Jim Pesanka
> Sent: Tuesday, June 07, 2005 5:29 AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] Re: 1 (2?) man
> "working" Disney(ish)
> Nautilus sub on ebay
>
> Thanks Ian. Very informative, and I appreciate the
> effort you went to.
> You've given me much to think about that I wouldn't
> have realized on my
> own.
>
> Would anyone else care to comment on the Ebay sub
> please? I'd like to
> gather as many opinions as I can. Perhaps some of
> you with actual
> experience? Dan, Carsten, Alec. Vance, or others?
> And also those who
> may have not actually built a psub yet but have
> spent some time
> designing them. Does the Ebay Nautilus sub look
> like a good one to you
> or not, and why?
>
> I guess what I'm asking is, "What should an
> inexperienced prospective
> buyer (like me) be aware of about this particular
> type of submarine?"
>
> Only five days left in the auction.
>
> Cheers!
>
> Jim
>
> Ian Roxborough wrote:
>
> Welcome, Jim.
>
> The "K250/350 hybrid" was a submarine that was for
> sale on ebay
> in
> late 2004. It was close (rather subjective) to my
> house so I
> took
> a look to see if it was worth buying. It was made
> from K250
> plans,
> but with lots of changes from the builder (some
> bad), it also
> had
> some K350 styling such as the conning tower. The
> picture are on
> the moki picture exchange under "2 person k250".
>
> Internal framing. Most pressure vessel have ribs
> along the
> inside
> (or outside) of the pressure vessel. These are very
> important
> and
> are the only reason the sub can dive deep without
> being crushed.
> If you look at this picture in the K250 hybrid I
> was talking
> about:
>
>
http://www.prismnet.com/~moki/20041127.134008/Kx50_hybrid5.jpg
> You seen "hoops" on the inside of the
> pressure-vessel spaced
> every
> so often. If you look at the picture of of the na!
> utilus sub:
>
>
http://www.prismnet.com/~moki/20050605.153205/f9_3.JPG
> There are no "hooks" space every so often. There is
> a band on
> the
> inside, maybe it's for mounting equipment, but it
> won't provide
> much re-enforcement of the pressure vessel (even if
> there where
> many of them). This is big reason I would not dive
> in it. Maybe
> it's safe to pop under the water can come back up,
> but without
> proper ribbing it will have a shallower colapse
> depth. The
> colapse depth can be calculated, but any out of
> roundness in the
> hull will reduce it further.
>
> "little bottles". I meant little bolts (sorry I was
> sleepy) as
> in nuts'n'bolts. They go all the way thru the view
> port housing
> from the inside to the outside. This means drilling
> holes in the
> viewports. As well as more holes in the sub...
>
> I think the peddle power is via a hand crank.
> Rather than foot
> peddles. The prop looks pretty, but my gut says
> that sub won't
> go over 1knot under it's own power.
>
> "never been underwater yet" means you are buying a
> pile of
> submarine
> shaped scrap metal. You will be the one that makes
> it a
> submarine,
> by removing what is wrong, sanding the paint and
> inspecting all
> the
> welds, grinding out and re-welding where needed,
> fitting the
> missing
> components, adjusting things for short comings in
> the design...
> I don't mean to put you off, just give you an idea
> of what you
> are
> getting into. I would do it if I found the right
> sub.
>
> I like the two large side viewports. It looks like
> it might be
> the same as the forward big viewport. This is a
> change I that
> I've
> often thought would be nice on the K350, but the
> would have to
> be
> bigger housing inside the sub in order to support
> the ribs that
> it
> would need to disrupt.
>
> Hope this helps,
> Ian.
>
> On Mon, 6 Jun 2005 14:59:27 -0700 (PDT)
> Jim Pesanka wrote:
>
> > Hello everyone,
> >
> > My name is Jim and I have ! been a member of
> Psubs for a
> while. I have a genuine interest in submarines and
> especially the
> personal variety, though I have not actually built
> one yet. I've enjoyed
> reading the messages I've found here, but this is
> the first time I've
> had a reason to actually post one myself. I have a
> question, but first
> allow me to express my congratulations to your new
> psub owner, Pierre,
> on his recent success with the submersible "Big". I
> look
=== message truncated ===




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