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

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

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
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> 
> 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