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Re: [PSUBS-MAILIST] Another nutcase here.



Bill,
 
   Thanks for that.  So basically, you get the weight you need via the keel.  That makes sense.  Also safer too by having the keel jettisonable, up she pops like a cork, as long as you're not too deep and "bend" yourself I guess.
 
   I have been following the hull test threads very carefully.
 
   I don't like the idea of being exposed to the depth pressures, even if it's not very deep.  I seem to be particularly sensitive towards that.  I can't dive / swim very deep without my head wanting to explode (implode I suppose).
 
   Still thinking.....pondering....planning.
 
Myles.
----- Original Message -----
From: Akins
Sent: Thursday, October 27, 2005 4:50 PM
Subject: Re: [PSUBS-MAILIST] Another nutcase here.

Hi Myles.
 
In overcoming the buoyancy of the hull you might make an ambient heavy by filling its keel with lead, bricks, concrete, maybe even sand, anything heavy for ballast.
 
I've seen pictures where fellows who were taking their sub out for its first test took a bunch of bricks along and if they weren't heavy enough, just started loading bricks
 
into the sub's bottom until they were heavy enough.  
 
To use the same weight as you said to make a pressure hull, you have to build interior hull reinforcement rings, have a thicker pressure hull and also worry about the
 
roundness of the pressure hull and how much pressure it will take. You have to worry about leaks and hull penetration fittings leaking. You have to do an unmanned
 
pressure test like we have been recently and presently been discussing in the group's postings.
 
The ambient design does away with all that by simply keeping the water out with air pressure.  Theoretically the ambient hull outer walls could be as
 
thin as a beer can since the pressure inside will be the same as the pressure outside. Of course you wouldn't want to make one that thin because it wouldn't be practical,
 
but it would be possible to do so. There are fellows here who build pressure hulls all the time, but it is much harder to build a pressure hull than an ambient one. Although
 
there have been wooden, fiberglass and epoxy pressure hulls made for 1 atm subs that didn't go very deep, they still are much harder to build than a ambient hull.
 
The main advantage of the ambient hull for scuba depths diving is that you can make it out of practicall any material and you can make it in almost any shape you want
 
and do not have to make it spherical as most pressure hulls are to maximize resistance against extreme external water pressure. The main detraction of an ambient design is that
 
your body will be under the same pressures as a scuba diver at whatever depth you dive to and have to adhere to dive tables just like a diver does so you don't get the bends. Also
 
as you submerge and increase the air pressure inside your sub to equalize the outside water pressure and keep it out, you have to pinch you nose and blow to equalize your sinus
 
cavities just like a diver does as he decends. Also you cannot exceed safe scuba diving depths so you cannot go nearly as deep as a 1 atm sub can go. But for shallow sub diving
 
not to exceed a maximun of 130 ft, an ambient design would be much cheaper and easier to build than a 1 atm sub.
 
Bill.
 
 
 
 
----- Original Message -----
From: Myles Hall
Sent: Thursday, October 27, 2005 4:18 PM
Subject: Re: [PSUBS-MAILIST] Another nutcase here.

Rick,
 
   Love it !!
 
   I was giving thought to an ambient, since my dive depths aren't going to be very deep, but, I don't really understand how you can make them heavy enough to sink.  If you can, why not just use that weight to make a pressure hull instead ?  It's not totally clear to me.  I can get access to good quality pipe and weld so, I just thought it would be best to go 1 ATM.  (By the way, plywood here isn't cheap.).  Your concept of keeping the costs down has a ton of merrit though.
 
Myles.