Re: [PSUBS-MAILIST] Carbon Fiber

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

----- Original Message -----
From: "Chris Horne" <chris@chrishorne.com>
To: <personal_submersibles@psubs.org>
Sent: Monday, August 14, 2000 12:34 AM
Subject: Re: [PSUBS-MAILIST] Carbon Fiber


" I wouldn't look into it for one reason: cost. carbon weave is about $80/sq
yd. Given that it's going to take many yards and many layers, you'd be
looking at a lot of money just for the fiber cloth....-chris"


A few more thoughts regarding composits versus steel for use in submarines:

If you want to certify your boat, the pressure hull will have to be made of
steel to meet the regs, won't it?

People say "fiberglass is lighter", but is that what we really want?  Subs
displace a lot of water, and generate a lot of buoyancy.  They need to be
heavy to overcome this.  Steel is perfectly suited in this regard.  Wouldn't
a composite hull need to be extraordinarily thick to be heavy enough to
counteract displacement buoyancy?  And then, wouldn't a steel hull of
identical outside dimensions and displacement, but with thinner walls, have
a greater and more useful inner volume available for occupants, components,
and such?

Some say composits are easier to work with, but I don't know if that's true.
If carbon fiber needs a pressurized autoclave to cure properly; and in any
case we've got to make extensive masters and molds; and then go through the
labor of casting up and sanding down, I'm not all that sure it would be
easier.

And then again, Chris brings up the valid issue of cost per square yard of
material.  Shop around, and steel is pretty reasonably priced.

The basic tooling and manufacturing methods used when working steel are
pretty modest, really.  It's great stuff, and fun to work with.  And for
those few pieces you can't form yourself, there are shops that will do it
for you.

If anyone is inclined toward composits because of an aversion to working
with steel due to a lack of training or equipment,   I suggest get into
metal fabrication.  It's not as intimidating as it looks; and once people
start working in steel, my experience is they usually come to like it quite
a bit.

VBR,

Pat