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Re: [PSUBS-MAILIST] O rings and pressure
My tanks (two 360 cu ft capacity) will be located outside. Since I have little room inside, my sub is hydrobatic, with a cockpit of 27"dia by 82" length. Your correct of course about sheering a 1/4 steel rod with your bare hands (don't know what we were thinking). My concern with over pressurizing the ballast tank with HP air may be over cautious, as long as you just give short bursts and let the water exit I guess you'd be ok, that is something that would come with experiance. However, you could over pressurize if you left that valve on for too long of a time. Here is a link to my model:
http://www.ojai.net/ojaibees/index.htm I've added dual rudders like my first model but I do not have pictures yet.
Brian
----- Original Message -----
From: <adteleka@in-tch.com>
To: <personal_submersibles@psubs.org>
Sent: Thursday, November 20, 2003 12:15 PM
Subject: Re: [PSUBS-MAILIST] O rings and pressure
> I was assuming Brian was going to have his HP tanks inside the sub. It
> seems like the majority of people are afraid of the tank releasing all of
> its air inside the sub. This is one of the areas where it is a matter of
> opinion and the relevance of safety can be discussed endlessly with it
> canceling it self out of the discussion.
>
> I would put them in the sub.
> If you put the tank(s) in the sub make sure you have an altimeter (which
> you would want anyway), this way if there is a slow leak in a connection
> you will detect it. Make sure you select a tank size that will accommodate
> your volume-pressure calculations; if the tank were to release all of its
> volume into the sub your atmosphere should not exceed 2atm. If this were to
> happen to someone, they should sell there sub. Just kidding, just turn off
> the tank, switch to your backup or tighten the connection. There is no need
> for a regulator; the desire to limit flow can be taken care of by the type
> of valve you use to blow your tanks (not the valve on the tank). This
> simplifies everything while allowing you more control, with flow and the
> system. Sub weight increase (minus the buoyancy of your tanks if out side)
> so that could be a disadvantage forcing you to toss some lead out or
> increase displacement. Having another hole in your sub to control the valve
> or having a normally closed solenoid works but is a more expensive route.
> These points are but a few and are a matter of opinion based on what your
> sub is going to do. What is important in not being biased right off the
> bat, because you can overlook something that you might regret later.
>
> Anyone ever torque a 1/4 in. steel rod to failure with your bare hands or
> even with, let's say, a 4 in lever arm? If you have to use a cheater bar in
> your sub, something is too tight! There are higher grades of steel which
> can reduce diameter also.
>
> Adam
>
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