Re: [PSUBS-MAILIST] Carbon Fiber

["Captain Nemo" <vulcania@interpac.net>]

----- Original Message -----
From: <TeslaTony@aol.com>
To: <personal_submersibles@psubs.org>
Sent: Monday, August 14, 2000 5:12 AM
Subject: Re: [PSUBS-MAILIST] Carbon Fiber


"Yeah, but what are the advantages to getting it certified? I'm not planning
on using it for commercial purposes, although if I need to sell it I could
have a few problems....."

Well, you've got a point there.  Not every sub needs to be certified, I
suppose.  Depends on what it's going to be used for.  My sub is a little
"unusual"; I still have lots of fun with it, and the people who've offered
to buy it didn't much care if it was certified or not.  They just wanted a
functional replica of the Nautilus.
>
>
"Actually I think that lighter _is_ better since I want to have one or more
drop weights, and it's nice to be able to lose as much weight as possible if
you have to surface fast."

Well yeah, I can see your point; and I suppose there are pros and cons to
just about everything.  Having the extra hard ballast in the form of a drop
weight will definitely give you a lot of positive buoyancy when it's time to
go.  And I've thought about this, too.  A few of the problems I encountered
were: the size and shape of the extra ballast: making a releasable
attachment between the ballast and the hull; the potential for structural
failure between the steel weights and the composite / frame hull structure;
etc.  To me, it just seemed more convenient to have weight and buoyancy
self-compensate by using a hull material that compensated displacement
weight requirements integrally, while minimizing the need for add-on
components.  But there are two sides to every coin.  Done right, composites
with releasable ballast could have some advantages. Like Suds said, the
stuff is easier to form complex shapes with; and to that I'd add "it doesn't
rust, either".
>
" Renting a pressurized autoclave is probably cheaper than getting a shop to
make an elliptically shaped steel hull that can handle the proper depths,
and  using a foam core system might help with shaping the material (which
might be a problem if it has to be heated, but that's why I asked you guys,
isn't it?).

Well, Tony, I don't know what it might cost to rent a pressurized autoclave;
but the one I saw (and I think it was in a program about the construction of
DEEP FLIGHT) was a walk-in chamber.  I don't know if one big enough to cure
something the size of hull components would be economical to rent; but then
again, somebody might be able to find an economical way to go on this point.
(Maybe some company that  has one would rent you time in it, for example.)

But most general metal fabrication (a lot of what it takes to build a sub)
can be done very reasonably in a home shop with a welder, torch, and some
forming tools and grinders.  Shaped plates can be professionally
manufactured and then weld-assembled by the home craftsman.  Agreed: it
costs megabucks to acquire the tooling necessary to produce a steel teardrop
hull; one made out of composites could be less expensive.

But then again, why do we need an eliptical hull?  For hydrodynamic
efficiency?  A nice compromise might be to make a more conventionally-shaped
steel pressure hull (say, a cylinder with hemispherical endcaps) and enclose
that in a composite shell of the desired shape.  This way, the p-hull would
be strong, easily made, and (if it matters) certifiable; and the outer hull
could be easily produced because it could be free-flooding and wouldn't need
to withstand depth pressure.  One might even conceal integral ballast tanks
in the void between the p-hull and outer shell.  Done that way, one could
probably avoid expensive composites and the autoclave, and lay-up a suitable
teardrop shell of regular fiberglass built upon a basic metal frame that
bolts to the p-hull.

" Unfortunately there are three steel suppliers in my local area, one only
does "1018" (very soft steel, no good for a sub), the other two are
junkyards that I refuse to do business with unless I absolutely have to.
Now I could always order my stuff directly from the manufacturer, but how
much would 1000+ lbs. cost to ship? I think the autoclave and the composites
are starting to look cheap..."

Yeah, supply can be a problem, and one definitely needs to shop around.
Back in Cal where I built the Nautilus, a place called ALCO sold all kinds
of metals.  At first they didn't want to deal with me; but when I showed
them pictures of what I was building, they got behind me and gave me good
deals on materials.  (Let me walk the yard and pick whatever I wanted from
the bins and racks.)  And,  an absolutely wonderful gent by the name of Joe
Garske let me roam his boatyard, and sold me stuff at next-to-nothing
prices.

Now, Joe was one of those tough-as-leather guys who operates a crane-barge
company, and was building steel ships since WW-II.  When I first came to his
boatyard,  he called me a "playboy" and was running me out of the place
until I showed him I knew how to compute the weight of metals and the
displacement of oddly-shaped vessels.  Only then did he start to take me
seriously, and agree to sell to me.  As my project progressed, he'd come
over and see it from time to time; and his willingness to support me
increased when he realized I was actually making progress.  So, I know
getting acceptance can be hard.

Submarines are unusual projects; and guys in the business of working with
steel are probably going to look at the neophyte sub-builder like he's some
kind of wingnut or something.  That's to be expected.  But I was able to
convince people with "the means" to help me, and they eventually took an
interest in my work and gave me more-than-reasonable prices.

To anyone wanting to build a sub, and needing the help of people with access
to stock and equipment, I say: be persistent.  Look 'em straight in the eye,
tell 'em who you are, and tell 'em what you want.  Expect them to roll their
eyes, laugh and cuss,  and spit on the ground; but don't give up.  Keep at
'em, and if you can convince them you're serious, you might be surprise at
how much help they may be willing to offer.  And if they still won't go for
it, don't give up.  Find someone else who will.  If you believe there's a
way, you just might find it.  That's how it went for me, anyway.  It wasn't
easy, but it wasn't impossible, either.

>
"After doing some blacksmithing I got pretty hooked on steel, although my
equipment consists of one coal-fired antique wagonback forge, a 55# cast
iron anvil, misc. hammers, chisels, punches and stands, better for making
swords
 than subs (or plowshares)."

Hey, I got a horse that needs shoes!  ;-)  (Not really, but I couldn't
resist the joke.)

"As for someone else being able to make one of the hulls I want...I dunno,
it's elliptical, 10+ feet long, 4- or 5- feet wide and a little flattened,
not exactly sure how flat it will be though, and I have never seen any
equipment yet that can do something like that yet, nor have I seen anything
like it either."

Yeah, I hear ya, man.  Why not give that idea I mentioned above (a steel
p-hull in a fiberglass shell) some thought?  Might be the easiest way to
have the best of both worlds, and produce a boat that will do what you're
looking for at the minimum expense of time, effort, and money.

"Hey, maybe one of you guys can prove me wrong about Carbon Fiber or other
Composites being cheaper and easier for me to use in the long run, you would
make me one very happy man (especially since I don't know where to get
composites in the first place).  Anthony"


At the end of the day, I do see the pros and cons you're talking about.
Sounds like your main objective is a streamlined submarine, no?  A steel
teardrop could be expensive if not impossible for the individual craftsman
to achieve.  Compound curves might be easier and cheaper to cast in
composites than they are to form and weld in steel.  But again, the best of
both worlds might just be that steel p-hull inside a fiberglass shell I
mentioned earlier.

Anyway, that's about the best suggestion this "backyard bandito" can offer.
Whichever method you decide to use, I wish you good luck with your project.

VBR,

Pat