Re: [PSUBS-MAILIST] Compressed Air Quality

["Marsee Skidmore" <heyred@email.msn.com>]

Rob,

I was hoping that someone who knew would answer your question. Since no one
has, I'll say, "I dunno, but I think so." I concur with all of your
suppositions. I don't intend to blow ballast at depth, since I'm kinda
partial to droppable ballast. In the event that I do, I intend to have 2,000
psi (min) in the high pressure air bank competing with 500 psi (max)
ambient. With big lines, that would take a mighty long ice cube to block.

I'm curious about your Thresher reference. I thought that Thresher's
plumbing problem was due to a defective weld. - Joe

----- Original Message -----
From: Robert Carlson <rob.carlson@gte.net>
To: <personal_submersibles@psubs.org>
Sent: Sunday, November 12, 2000 7:00 PM
Subject: [PSUBS-MAILIST] Compressed Air Quality


> Is air used for scuba diving dry enough for blowing MBTs?  The reason I
> ask is that the USS Thresher sank during sea trials due to the fact that
>
> the air when discharged to the MBTs created a tempature that was below
> the Dew Point and consequently the orifice quickly froze with ice.
> Following this incident the US Navy created rigorous standards for HP
> air. Are psubs in jeopardy of a similiar error by using scuba air?
>
> I do recall that scuba tank air is dry (based on the cotton mouth after
> the dive) but is it consistantly dry enough for psub purposes?  Or is it
>
> that the possibilities are minimized because of a) the diameter of pipe
> is large enough b) the duration of a MBT blow is shorter on a psub and
> thus less likely to happen c) combination of a and b and that scuba air
> is dry enough.
>
> I'm just curious if anyone has given this much thought.  I do realize
> that this probably is not a major issue otherwise there would more
> psubbers at the bottom of some dark and cold body of water however my
> icuriosity has made me ask why this not an issue.
>
> Regards,
> Rob Carlson
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