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Re: [PSUBS-MAILIST] Bill Gifford's Project

To: <personal_submersibles@psubs.org>
Subject: Re: [PSUBS-MAILIST] Bill Gifford's Project
From: "Steven Mills" <barycenter@earthlink.net>
Date: Mon, 26 May 2003 11:01:21 -0700
References: <20030524052552.75704.qmail@web13501.mail.yahoo.com>
>From: Chris Nugent <dirkpitt77@yahoo.com>
>
>     Steve....although I don't have the DVD of U571, I've seen it a coupla
>times n I remember that scene too.  A surprising detail coming from
>Hollywood, considering it's what I'd call an otherwise mediocre movie.
>They also did this same effect in "K-19:  The Widowmaker".
> 

Great, then I wasn't seeing imaginary things then!  I confess when
it comes to sub movies and docu's my critical eye for good and bad
plots go out the window.  I'll watch a sub film once or twice then go back
to pick out background details. What was that movie with that
"Frazier" character..."Down Periscope"?  If memory serves, the sub
used in the film was the "Pampanito"?  I believe it was the last time
she saw service before being placed on permanent exhibit near
Fisherman's Wharf in SF.

My movie collection for Subs is sadly lacking.  I need to set aside a
budget for this.  I'm going to die a poor man [ but a happy one! ].

--Steve





> 
> Steven Mills <barycenter@earthlink.net> wrote:
> >From: Dan H. 
> > 
> > I don't really have answers to your dual hull design.
> >.............snip...............
> 
> Thanks Dan,
> 
> My curiousity was more 'textbook' than practical.
> Ever since the topic of Bill's pSub came up I've been seeing
> propane tanks everywhere I go. They seem to come in a
> variety shapes and sizes. I *might* consider designing an
> ROV around one, a shallow submersible, or wetsub.
> Checking past messages in the archives, there seems to be
> a general consensus to stay away from designs using propane
> tanks.
> 
> I've been doing a little research on framing and stiffening rings.
> [ along with all the other topics brought up here ; batteries, propulsion,
> ballasting...etc. whew! ]
> 
> Has anyone seen the movie "U571" ? I've only seen it once on T.V.
> I could swear there is a scene where the sub is under depth charge
> attack and the compression shock exposes [ or outlines?] the frames
> along the hull. I was quite surprised by that added special effect.
> Does anyone have a video or dvd of "U571" Perhaps someone could
> review it and this particular scene? Or maybe I just imagined it.
> 
> --Steve
> 
> > 
> > ----- Original Message -----
> > From: "Steven Mills" 
> > To: 
> 
> > Sent: Friday, May 23, 2003 11:52 PM
> > Subject: Re: [PSUBS-MAILIST] Bill Gifford's Project
> > 
> > 
> > > >From: Dan H. 
> > > >
> > > > I visited Bill's site and read what you quoted. Bill's project sure
> > looks
> > > > interesting but I wish, for confusion sake, Bill would have noted that
> > his
> > > > propane tanks that were tested to 325 PSI and rated at 250 PSI for
> > INTERNAL
> > > > pressure! External pressure is a TOTALLY different matter. I'm sure
> > Bill
> > > > realizes this and is designing accordingly.
> > > >
> > >
> > > Thanks. That thought had occurred to me just before receiving your
> > > response.
> > >
> > > Perhaps I need a little clarification on the definition of dual pressure
> > > hulls. Is Bill's design a dual hull or a reinforced single pressure hull
> > > [ using the small tube and frames for reinforcement ; and the smaller
> > > tank left open ended after the cut or capped-off]? The ends of the
> > > smaller tank were cut and welded to the larger for hard ballasts.
> > > For simplicity, my mind envisions something akin to a thermos bottle;
> > > 2 closed vessels reinforced with frames or stiffening rings between
> > > the 2 hulls. [ Which brings me to the next question...]
> > >
> > > > One thing to consider when designing one tank nested inside another is
> > that
> > > > you can't weld your framing to both tanks unless the difference in size
> > is
> > > > great.
> > >
> > > So, I would think that the framing would be welded on the outside of the
> > > inner hull? The outer hull would not only be subjected to pressures
> > > initially, but also to temperature differentials? The contraction and
> > > expansion over time would fatigue and stress the welds at the inner
> > > part of the outer hull first if the 2 hulls were welded together at the
> > frames?
> > > The temperature in the inner hull would be affected by intenal environment
> > > ie., body heat and residual mechanical/electrical heat? Or are these
> > > minute considerations?
> > >
> > > >Even if you design it strong enough without the frames welded to
> > > > both tanks, you still have the risk of corrosion in places that you
> > can't
> > > > access for inspection.
> > > >
> > >
> > > Would a foam, dessicant, or bonded covering [ anodizing the steel?]
> > > solve this problem?
> > >
> > > --Steve
> > >
> > >
> > >
> > > > Dan H.
> > > >
> > > > ---- Original Message -----
> > > > From: "Steven Mills" 
> > > > To: 
> 
> > > > Sent: Thursday, May 22, 2003 1:34 PM
> > > > Subject: Re: [PSUBS-MAILIST] Bill Gifford's Project
> > > >
> > > >
> > > > > >From: Warren Greenway 
> > > > > >
> > > > > > They are rolled and welded (so, yes, they do have a
> > > > > > seam.) The ends are then welded onto the tube. This
> > > > > > is standard practice, and while there may be variation
> > > > > > you can bank on them being built this way.
> > > > > >
> > > > > > Warren.
> > > > >
> > > > > Thanks.
> > > > >
> > > > > Bill uses 2 tanks with the same ASME rating, but it is a single
> > > > > pressure hull. [ see quote/specs below ]
> > > > >
> > > > > If a double hull were to be designed, would you have the inner hull
> > > > > at a stronger and thicker spec than the outer hull? [ using 2 propane
> > > > > tanks ]
> > > > >
> > > > > Also, this might seem an oddball question or inconsequential, but
> > > > > should the weld seams on both hulls be parallel and lined up with
> > > > > each other?
> > > > >
> > > > > --Steve
> > > > >
> > > > > ....quoted fromBill Gifford's website....
> > > > > http://www.giffordmarineinc.com/sub/little_gato5_9_01.htm
> > > > >
> > > > > "I have chosen to use two new propane tanks to form the pressure hull.
> > > > > Each tank is made of A-516 grade 70-pressure vessel steel, .270 inch's
> > > > > thick. Both tanks were pressure tested to 325 pounds. They have a
> > working
> > > > > pressure of 250 pounds and are ASME rated with a spec. Plate on each
> > > > > tank. I am installing three by one half-inch reinforcement rings every
> > > > two-foot
> > > > > on center. Plus additional deck and bulkhead framing. The one-tank
> > easures
> > > > > 17.6 ft. long and the other is 9 ft. I have cut a hole in the top of
> > the
> > > > larger tank,
> > > > > around that I intend to install the conning tower, which is made up of
> > > > parts
> > > > > of the smaller tank and additional plate. I have cut the ends from the
> > > > smaller
> > > > > tank and have connected them on each end of the larger tank for hard
> > > > > ballast. I have purchased a eighteen-foot by two foot by quarter inch
> > pipe
> > > > > for the soft ballast tanks. The pipe was split log ways and will be
> > > > attached
> > > > > to each side, to form the side tanks. The sub will have a displacement
> > of
> > > > > approx. 18,000 lbs. "
> > > > >
> > > > > >
> > > > > > --- Steven Mills wrote:
> > > > > > > I haven't examined a propane tank closely, but are
> > > > > > > they filament
> > > > > > > wound and rolled or are the ends welded to the tube?
> > > > > > > Is the tube
> > > > > > > seamless or also rolled and welded? Are they all
> > > > > > > manufactured
> > > > > > > the same way?
> > > > > > >
> > > > > > >
> > > > > > > --Steve
> > > > > > >
> > > > > > >
> > > > > > > ----- Original Message -----
> > > > > > > From: Coalbunny 
> > > > > > >
> > > > > > >
> > > > > > > > Yes, it is! What about the innerds? Can we get a
> > > > > > > spec sheet and
> > > > > > > > drawings if we want to make something similar?
> > > > > > > > Carl
> > > > > > > >
> > > > > > > >
> > > > > > > > Steven Mills wrote:
> > > > > > > > >
> > > > > > > > > Wow, that's quite impressive !
> > > > > > > > >
> > > > > > > > > It's a beautiful boat.
> > > > > > > > >
> > > > > > > > > --Steve
> > > > > > > > >
> > > > > > > > > ----- Original Message -----
> > > > > > > > > From: Jeremy Crawford 
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > > If anyone hasn't checked out Bill's Sub lately
> > > > > > > you should, the exterior is
> > > > > > > > > > done and it looks awesome. Kudos Bill, you
> > > > > > > have done a fantastic job!
> > > > > > > > > >
> > > > > > > > > > Best Regards,
> > > > > > > > > > Jeremy
> > > > > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > http://www.giffordmarineinc.com/sub/sub_5_16_03/Sub_5_16_03.html
> > > > > > > >
> > > > > > > > --
> > > > > > > > "Indeed, desire is the seed of thought, the prime
> > > > > > > force that activates
> > > > > > > > the mechanism of the mind." -- Kama Sutra
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > > __________________________________
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> > > >
> > > >
> > >
> > >
> > >
> > >
> > 
> > 
> 
> 
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