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Re: [PSUBS-MAILIST] Bill Gifford's Project
Steve,
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.
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. 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.
A double hull has it's drawbacks.
Dan H.
---- Original Message -----
From: "Steven Mills" <barycenter@earthlink.net>
To: <personal_submersibles@psubs.org>
Sent: Thursday, May 22, 2003 1:34 PM
Subject: Re: [PSUBS-MAILIST] Bill Gifford's Project
> >From: Warren Greenway <opensourcesub@yahoo.com>
> >
> > 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 <barycenter@earthlink.net> 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 <coalbunny@vcn.com>
> > >
> > >
> > > > 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 <ISMASC@hotmail.com>
> > > > > >
> > > > >
> > > > > > 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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