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

[Ray Keefer <Ray.Keefer@Sun.COM>]

Hi Coalbunny,

Your sub is as safe as the weakest link. If you have a viewport that
is only as good as 200 feet, it doesn't matter if the hull can make
it to 900 feet. The watertight interity will already be compromised.

In the case of a 200 foot viewport, go no deeper then 100 feet for a 2:1 
safety factor. If 100 feet isn't enough, forget about reinforcing the 
viewport. Just build it better in the first place. Design it for 900 feet
for that 900 foot hull.

Regards,
Ray

> Date: Wed, 08 May 2002 11:12:09 -0600
> From: Coalbunny <coalbunny@onewest.net>
> X-Accept-Language: en
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch as an 
emergency  esca...
> Content-Transfer-Encoding: 7bit
> 
> Now I'm curious.  If a sub's hull can do a depth of say, 900 feet, but
> is limited because the glass/lexan/plexiglass won't go below 200 feet,
> wouldn't it help some if you were to back the porthole material with
> something like an expanded steel screen?  That way, in the event of an
> accident, the porthole does not explode inward.  Yes water does get in,
> but not in the explosive manner.  Of course this is theory only, so tell
> me where this idea is wrong.
> Carl
> 
> 
> DBACKIDS@aol.com wrote:
> > 
> > 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.
> 
> -- 
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