Re: [PSUBS-MAILIST] Using a commercially available hatch as an emergency esca...

["Jeff Post" <jeffpost@rawbw.com>]

I think we are missing the boat here, a little. There is no reason you can't
use glass or plexi for submarines. Nobody has said a word about shape and
thickness! You need to remember that Alvin's viewports ARE plexiglass, and
Alvin has been deeper than 13,000 feet. The spec's for Alvin's viewports are
"flattened cones three and a half inches thick that flare at 45 degrees,
from five inches on the inside to a foot on the outside".

Flat plexiglass windows are best only used on subs built out of used propane
tanks :)

JP

----- Original Message -----
From: Coalbunny <coalbunny@onewest.net>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, May 08, 2002 9:55 PM
Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch as an
emergency esca...


> What are the depth/pressure limits for glass and plexiglass?  What about
> bullet-proof glass?
> Carl
>
>
> Herve wrote:
> >
> > There is confusion here between materials and tradenames.
> > Lexan, plexiglass... trade names.
> > materials are actually: polycarbonate or acrylic.
> > polycarbonate better fits view ports and windows for submersibles
although
> > soft enough to be scratched and wornt out rapidly.
> > Tempered glass cannot be used in 1 atm subs, ambient pressure subs allow
use
> > of tempered glass which is much more better for viewing, clarity and are
> > scratch proof.
> > Tempered glass is a heat treatment of glass which renders the glass
> > frangible in case of shock to avoid projection of sharpened pieces of
glass,
> > in the process the glass actually gain 4 times the strengh of the
regular
> > glass.
> > Greg , Dont need an escape hatch either since the windows  could be
> > shattered with the apropriate tool in case of an emergency and to get
out.
> > Herve
> > ----- Original Message -----
> > From: <rjune@fuse.net>
> > To: <personal_submersibles@psubs.org>
> > Sent: Wednesday, May 08, 2002 3:18 PM
> > Subject: Re: Re: [PSUBS-MAILIST] Using a commercially available hatch as
an
> > emergency esca...
> >
> > > I think you've got it backwards.
> > > I have both lexan and plexiglass downstairs.
> > >
> > > I can pound away on a piece of 1/4 inch lexan
> > > with a 2 pound ball peen hammer and only dent it.
> > >
> > > and 1/2 thick plexiglass shattered after one hit.
> > >
> > > not only that but lexan can easily be machined,
> > > drilled, and even tapped.
> > >
> > > Additionally, I volunteer at a local aquarium,
> > > where we have tunnels constructed of lexan
> > > the floor in one of the tunnels is a flat pieces of
> > > 3" thick lexan and has a rated capacity of 6000 lbs.
> > >
> > > an additional thought ... the same piece of lexan
> > > was installed when the aquarium was built over
> > > five years ago and sees the foot traffic from
> > > 1000 to 2000 people 300 plus days a year and it still
> > > looks good
> > > >
> > > > From: Ray Keefer <Ray.Keefer@Sun.COM>
> > > > Date: 2002/05/08 Wed AM 11:54:59 EDT
> > > > To: personal_submersibles@psubs.org
> > > > Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch as
an
> > emergency esca...
> > > >
> > > > Hi,
> > > >
> > > > I worked in a plastic fabrication shop in my starving student days.
> > Everyone
> > > > got nervous when they had to cut lexan. Occasionally it would catch
in
> > > > a saw blade and kick back in shards. It is tougher then plexiglass
but
> > > > brittle also.
> > > >
> > > > Regards,
> > > > Ray
> > > >
> > > >
> > > > > From: DBACKIDS@aol.com
> > > > > Date: Wed, 8 May 2002 00:05:30 EDT
> > > > > Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch
as
> > an
> > > > emergency esca...
> > > > > To: personal_submersibles@psubs.org
> > > > > Content-Transfer-Encoding: 7bit
> > > > >
> > > > > Quick note on using Lexan: If you plan on cutting it yourself, be
> > careful,
> > > > > for it shards like a glass would, not melts right through like
plexi
> > would.
> > > > > (I built a 5" x 9" x 3' long "wet wind tunnel" (a wind tunnel,
with
> > water
> > > > > instead of air), and found out that plexi, when cut fast,
practically
> > melts
> > > > > itself back together, while lexan will shard off unless it is
covered
> > or
> > > > > taped. It was a fun project, too) Ok, I went off-track, but you
got
> > the
> > > > > point.
> > > >
> > > >
> > >
> > >
> > >
>
> --
> Watch your thoughts; they become words....
> Watch your words; they become actions....
> Watch your actions; they become habits....
> Watch your habits; they become character....
> Watch your character; it becomes your destiny.
>