Re: [PSUBS-MAILIST] new to this list - dry ambient sub??

[TeslaTony@aol.com]

In a message dated 5/15/01 4:42:14 AM Pacific Daylight Time, 
marius@sirius.inka.de writes:

> Hi,
>  
>  I'm a 16 year old young german (from the south of germany) and joined this
>  discussion group only some days ago.

Excellent! We need more young people around to irritate Carsten, Pat and all 
the other helpful madmen with questions along the lines of "How do you think 
a CO2 scrubber that uses algae will work?" (that was a question of mine that 
got some very interesting responses.....).

>  The PSUBS organisation is really great !! I found very useful informations
>  on the website www.psubs.org which helped me to get an overview about the
>  topic.
>  
>  At the moment I'm reading Ulrich Gabler's "U-Bootbau" (submarine design)
>  which covers many aspects and problems in designing submarines.
>  
>  Geographically I'm far away from deep lakes or even the sea - only small
>  lakes with depths to 20 or 30 meters are in range. But that's enough to
>  start with.
>  The main requirement for me is a great view - to the surface, to both sides
>  and last but not least to the ground.
>  
>  This could be achieved by a light - transparent - hull made of plastic (for
>  example acryl).
>  Can a hull of this material resist the pressure in the planned operating
>  depth (max. 30m, reserve to perhaps 70m) ??

I think just about any material will handle just about any depth as long as 
it's thick enough. Besides, I think there are commercially made subs with 
Acrylic pressure hulls (an acrylic dome or viewport would be considered part 
of the pressure hull, so for a full sub you would just calculate for a BIG 
dome).

>  With a pressure-compensated sub this wouldn't be a problem. If it operates
>  wet, a small hole is enough to equal exterior and interior pressure.
>  But I definitely want a dry sub - so I have to release pressurized air into
>  the hull when I dive and leave air out to the water when I rise, right ??

I have heard of a pressure compensation system that uses a SCUBA regulator of 
some type to make sure the seals on electric trolling motors don't let water 
in when they are at depths greater than they were designed for, and yes, as 
you rise you will have to release the pressure one way or another, and if you 
pressurized the hull with air then the easiest way to get rid of it will be 
overboard (bubbles, and lots of them).

>  Has anyone designed or even realized such a "dry ambient sub" or does it
>  make no sense (it may need too much air) ??

There are dry ambient subs out there, and at least one company that 
manufactures them, so you're not in wholly uncharted waters.

>  Or am I just to careful and "over engineering", and a hull of paper would
>  resist the pressure in 20m ;-)) ??

If you make a roll of paper and pressure treat it or something with epoxy 
then it should make a hull similar to fiberglass, but with the advantage of 
having the mornings headlines plastered all over the inside.

>  Greetings,
>  Marius Hillenbrand
>  
>  PS: I'm pretty sure my English isn't very well, we learn it at school but
>  only practical experience can make you really familiar with a language
>  
Hey, you english is better than my German by a longshot, so you're doing fine.

Best of luck with your sub!
Anthony