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

[rjune@fuse.net]

Herve - I agree with you... temperd galss is the best to use,
and also the most expensive based on required thickness
for a given design deapth.  Polycarbanate (Lexan) is my second choice,
and you are correct it has a relativly soft surface meaning that it
will scratch if abrasive cleanners are used.  There are some products 
out there that can be used to help restore scratched lexan.  As to plexyglass for me it is never a choice. 
> 
> From: "Greg Snyder" <snyde032@tc.umn.edu>
> Date: 2002/05/07 Tue PM 05:03:45 EDT
> To: <personal_submersibles@psubs.org>
> Subject: RE: Re: [PSUBS-MAILIST] Using a commercially available hatch as an emergency escape hatch.
> 
> Hi Herve -
> Do you think that 2 layers offers a benefit ( they quoted me for 2 layers of
> 12mm glass).
> Thanks-
> Greg
> 
> -----Original Message-----
> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org]On Behalf Of Herve
> Sent: Tuesday, May 07, 2002 2:16 PM
> To: personal_submersibles@psubs.org
> Subject: Re: Re: [PSUBS-MAILIST] Using a commercially available hatch as
> an emergency escape hatch.
> 
> 
> I used in my dry ambient subs, 1/2" tempered glass. cristal clear for ever.
> Lexan gets to easy and rapidly worn out, scratched and loses its clearness.
> Plexiglass cracks after a while under sun exposure.
> I tested my windows in 10 Ft water column when differential pressure never
> exceeds 2 Ft of water column.
> Herve
> ----- Original Message -----
> From: <rjune@fuse.net>
> To: <personal_submersibles@psubs.org>
> Sent: Tuesday, May 07, 2002 1:16 PM
> Subject: Re: Re: [PSUBS-MAILIST] Using a commercially available hatch as an
> emergency escape hatch.
> 
> 
> > never use plexiglass ... it is to week
> > use polycarbinate also called lexan
> > >
> > > From: Ray Keefer <Ray.Keefer@Sun.COM>
> > > Date: 2002/05/06 Mon PM 06:09:21 EDT
> > > To: personal_submersibles@psubs.org
> > > Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch as an
> emergency escape hatch.
> > >
> > > Hi Greg,
> > >
> > > Since your sub is ambient. If this window stays sealed at the surface it
> > > should stay sealed at depth. The pressure inside and outside will be
> > > even. The strenght of the frame and window only has to overcome minor
> > > differences in pressure.
> > >
> > > My concern is that the window is glass and frontal position of the
> window. I
> > > would hate to see you run into a rock and shatter the window.
> > > The spec says up to 3/4" tempered glass. Don't skimp, use the thickest.
> > > Use plexiglass if you can get it.
> > >
> > > Also keep in mind to use this exit you will have to be on the bottom.
> > > Else when you open the window the you will suddenly heavier with water
> > > coming in and will sink.
> > >
> > > If your sub subsides into the bottom silt, sand and stuff might come up
> to
> > > your opening. Limiting your exit and letting stuff into your sub to add
> > > weight.
> > >
> > > One last concern is you just can't open up the window. Air will bubble
> out
> > > and water will flood in. How violently depends on how much air will be
> > > displaced how fast. Perhaps a valve low down in the sub to let water
> flood
> > > in and one up high to let air out. Once water level is above the window
> > > opening the you can open the window without a large air bubble burping.
> > >
> > > Regards,
> > > Ray
> > >
> > > > From: "Gregory Snyder" <snyde032@umn.edu>
> > > > To: <personal_submersibles@psubs.org>
> > > > Subject: [PSUBS-MAILIST] Using a commercially available hatch as an
> emergency
> > > escape hatch.
> > > > Date: Sat, 4 May 2002 13:06:07 -0500
> > > > X-Priority: 3 (Normal)
> > > > X-MSMail-Priority: Normal
> > > > Importance: Normal
> > > > X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000
> > > >
> > > > Dear Psubbers -
> > > > I am in need of some advice.
> > > > As I refit the sportsub, I wanted to add an additional window that can
> > > > serve as an escape hatch.
> > > > I thought I would do this in the front lower section (by my knees and
> > > > shins when sitting).
> > > >
> > > > My design can tolerate an oval 27" by 16".  I can fit through if need
> > > > be.
> > > > I am looking at a commercially available window at the following link:
> > > > Model 71111 cut to these dimensions with the hinge removed and bow
> > > > handles in their place.
> > > >
> > > > http://www.beclawat.com/bec71111.htm
> > > >
> > > > My question is do you think that this will stay sealed in an ambient
> > > > cabin at a maximum of 130 feet?
> > > > Or am I just fooling myself.
> > > >
> > > > Open to suggestions-
> > > > Thanks-
> > > > Greg
> > >
> > >
> >
> >
> >
> 
> 
>