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Re: [PSUBS-MAILIST] Two man sub on ebay (or buying used submarines)
Hi,
First post from a newbie, but thought I might comment
on the welding issues. I work at a powerplant, have
some NDT certs (mag and PT), and am a CWI, as well as
a boiler inspector, so have gotten to be a little
familiar with some of these issues.
I am not sure where you are, or if there are any NDT
companies near you but if you can find a good
ultrasound man you can find out a lot more about your
welds then you can with xray. X-rays will show slag
and porosity pretty well, and if you have a crack or
delamination that runs the same direction as the beam
it shows up pretty well, but we have had trouble with
cracks that are 90 degs to the beam. A lot of both
the UT (shearwave) and X-ray are in the
interpetation, so the operator is really important.
Actually, you could probably find out a lot about the
welds if you had just a simple ultrasound d-meter.
These are just depth meters and catch a sound bounce
off of the back wall of the weld or piece of steel.
Really uneven readings would indicate slag.
But that would be sort of a half measure. In an
industrial settting we would sandblast all the welds -
interiour and exterior. A visual inspection would
tell you if they back gouged the welds and made a good
full penetration weld, or of they just gooped it over
and (horrors) puttied it to make is smooth. A dye
penetrant test would reveal pits, porosity, cracks
etc, and a dye penetrant setup is cheap to buy and
pretty much fool proof. It won't tell you what is
inside a weld, but when you are talking about 1/4" to
3/8" thicknesses you can see most of the problems
looking from either side. Pressure vessel
manufacturing code would require x-rays on the
longitudinal welds as well as the cirumferential
welds. Some of that is probably for insurance
purposes, and some for thicker-walled vessels.
Sorry, I didn't mean to run on so long, and maybe
everyone already is familiar with welding and NDE -
don't mean to be a know-it-all (because I am a real
newbie when pressure comes from the outside) but if I
was going to climb into a sub that someone else had
welded and I didn't know anything about it, I would
sandblast it and run a dye penetrant test on all
welds, inside and out. Bad spots would get ground
out, retested to make sure that the defect was gone
and carefully rewelded. These would be the minimum
steps that I would take to ensure that the welding was
done right, and that it wasn't likely to unzip.
Best of luck,
Dave
--- "Dan H." <jmachine@adelphia.net> wrote:
> Ian,
> I hate to put a damper on your enthusiasm but!
> I looked at the larger pic you sent and first off
> the view ports don't look
> right.
>
> The sub looks like a take off of a K design all
> right but the builder took
> many liberties. After reading Gene's look-see and
> what I see in the larger
> pic, you may not want it unless your only diving in
> the shallows. The
> trailer and tire issue you can deal with but not
> being sure of the weld is a
> bigger matter. You can have it X-rayed and repair
> if needed but that's not
> cheep.
>
> The bigger problem is with the view ports. From
> what I see in the pic,
> there isn't enough steel in the viewport housings.
> They are thin and don't
> have nearly enough surface to back up the lenses.
> They look to be about a
> eight inch lens size and need about an inch and a
> half of back up all they
> around the interior side of the lens. The hole on
> the interior side of the
> housing should be about six inches. You'd have to
> change all of them to
> ever take it to 250 feet.
>
> If you get it cheep enough, it may be good buy for
> materials but already to
> high priced for what you'd be getting.
>
> Sorrrry, Dan H.
> ----- Original Message -----
> From: "irox" <irox@ix.netcom.com>
> To: <personal_submersibles@psubs.org>
> Sent: Wednesday, November 24, 2004 6:02 PM
> Subject: Re: [PSUBS-MAILIST] Two man sub on ebay (or
> buying used submarines)
>
>
> >
> > Dan, thanks for the tips.
> >
> > Here is a bigger picture:
> >
>
http://www.watercraft.gs/uploads/adphotos/a30p1553012798orig.jpg
> >
> > It seems to have a built in trailer, which while
> interesting, isn't
> something I'm
> > really keen on. Atleast not on the implementation
> in the picture. But it
> does
> > look like it could be easily removed with bolts.
> Should I buy it I might
> consider
> > putting K350 style battery pods using the bolt
> holes from the tailer bits.
> >
> > I'll pay close attention to the welds. The
> welder/NDT talk from the first
> > Psubs convention is coming back to me now (I'll
> review the notes from
> > that talk before I view the sub).
> >
> > The end-cap thickness tip is a good one. I might
> beable to measure the
> > thinkness through the main (down pointing) view
> port (assuming it has
> > one).
> >
> > From the picture is appears that the builder was
> not planning on putting
> > in a rear thruster (something I might change -
> since I'm not planning on
> > side thrusters).
> >
> > I'm not too keen on the MBTs either, but it's a
> clever idea. According to
> > the guys I talked with today, it's got plumming
> and gauges inside, but
> > they don't really know much about submarines.
> >
> > Thanks,
> > Ian.
> >
> > -----Original Message-----
> > From: "Dan H." <jmachine@adelphia.net>
> > Sent: Nov 24, 2004 2:46 PM
> > To: personal_submersibles@psubs.org
> > Subject: Re: [PSUBS-MAILIST] Two man sub on ebay
> (or buying used
> submarines)
> >
> > Ian,
> >
> > It sure looks strange with the tires hanging off
> of it but It's an idea.
> > The pic is so small that it's difficult to see
> much. One thing for sure,
> it
> > doesn't look much like the Lake Diver pic they're
> using to sell it with.
> > I'd say it's just about fraudulent to sell it with
> that pic.
> >
> > Since there isn't any external battery pods I'd
> say it's a deviation of a
> > K-250 not K-350. I can't see if there's a rear
> thruster. K-350 has a rear
> > thruster. The hull ends are 3/8 thick on a K-350
> and only 1/4 thick on a
> > K-250 but you won't be able to measure it with out
> drilling a hole.
> >
> > Since it's never seen water, rust shouldn't be an
> issue. Just take a good
> > look at the welds. Visual inspection isn't all
> there is to it, but if
> they
> > look good, at least they might be good to the
> root. Just look at the
> > overall workmanship. If the builder spent the
> time and made what you see
> > look good, what you can't see is more likely to be
> good as well.
> >
> > Is it plumbed for air and tank vents and wired for
> power including fuses,
> > lights and thru hulls? The e-bay add implies it
> is. But they don't seem
> to
> > know much.
> >
> > If it's only a painted hull, it's about half done.
> >
> > Good luck, Dan H.
> >
> > ----- Original Message -----
> > From: "irox" <irox@ix.netcom.com>
> > To: <personal_submersibles@psubs.org>
> > Sent: Wednesday, November 24, 2004 2:35 PM
> > Subject: [PSUBS-MAILIST] Two man sub on ebay (or
> buying used submarines)
> >
> >
> > >
> > > Hi,
> > >
> > > from talking with one of the current owners, I
> think that it's this
> > > submarine here:
> > >
>
http://www.watercraft.gs/listing.php?main=Submersibles
> > >
> > > Unfortunately, the people who are selling it
> didn't build it and don't
> > know
> > > anything about it. So I've been unable to ask
> questions about the
> origin
> > > of the steel, fittings, pipes, qualitiy of the
> welds, etc... They are
> not
> > sure
> > > if it's a K350 or a K250 that's been modified.
> Built in trailer,
> > interesting,
> > > but I'm not sure it'll stay that way if I own
> it. It does appear to
> have
> > > internal battery box, everything else I know
> > >
> > > I'm going to try and see it as soon as possible.
> > >
> > > I think with subs getting more popullar we'll
> need to write a guide
> > > to buying used submarines.. ;-)
> > >
> > > Any tips (K250 vs K350 type differences,
> mistakes to look for, etc.)
> will
> > > be most welcome.
> > >
> > > Thanks,
> > > Ian.
> > >
> > >
> > >
> > >
>
************************************************************************
> > >
>
************************************************************************
> > >
>
************************************************************************
> > > The personal submersibles mailing list complies
> with
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