----- Original Message -----
Sent: Monday, May 23, 2005 9:41 AM
Subject: Fwd: [CSS H L HUNLEY] Re: Hunley
ambient? and ballast and dive plane operation.
Hello Bill - Here is one of the responses we got to your email.
I'll let you know if we get anymore. By the way I went into your site - wanted
to check out any Hunley Discussions and couldd not find them. Is there
an archive of these and can I get a copy. Thanks, George W.
Penington Webmaster and Editor of The Hunley.com website and
newsletters.
Note: forwarded message attached.
Now for Bill:
>This would make the Hunley
like an upside down glass trying to
>submerge without losing any air.
The only way the Hunley could
>submerge in my mind, would be for the
Hunley to use her
>forward motion and dive planes to force her
underwater, is this
>correct?
It is likely that your interpretation
is correct. The volume of the
ballast tanks is very small compared
to the entire interior. One of
William Alexander's 1902 drawings
shows little difference between
waterlines with the tanks empty and
full. The full waterline has
the hull submerged but most of the
hatch towers out of the water.
Since this amounts to very little of
the full volume of the
submarine, we can deduce it was designed to run
with a slightly
positive bouyancy and used to planes to dive and stay
submerged.
>Then once underwater the superior water pressure
would
>force water into the opened valve of the open top ballast tanks
and
>compress the atmosphere in the Hunley.
This is possible, but
would require carefully timed and coordinated
activity to accomplish
correctly and safely. The sub does have
complex piping between the
tanks but not enough information has been
released for us to do more than
speculate about its working. Once
again, there is very little volume
in the tanks to work with so it's
unlikely there was much
compression.
>Wouldn't this make the Hunley an ambient submarine
as
>opposed to being a 1 atmosphere submarine?
>Then when the
Hunley wanted to accend the crew would somehow utilize
>the compressed
atmosphere (how did they do that?) and a pump, to
pump
>the water
out of the ballast tanks and then the atmosphere in the
Hunley would
>decompress and return to 1 atmosphere
>and she would accend. Is
all the above of what I just wrote correct?
Technically, with the open
ballast tanks your characterization is
correct, but only to the point that
the tank vlaves were closed. We
know they were closed (at some
point) during normal underwater
operation because the second sinking, that
cost Hunley his life was
attributed to his leaving the forward valve
open. Pumps were used
to empty the tank, as far as we know, and any
effect of a slightly
compressed atmosphere was likely only casual and not
designed in.
>Also, has anyone done an analysis of how stable or
unstable the
>Hunley would be if she dropped her keel weight to return
to the
>surface, and were there any indications of that trying to be
done
> inside the Hunley artifact?
This would be an interesting
exercise. As far as we know, the three
(of seven) droppable weights
were designed for emergencies, so
intent would only be to get to the
surface. We can assume they
would have wanted to arrive there
rightside up. The four non-
droppable weights were probably there for
that reason.
The official reports about the weights have been
non-commital, but I
beleive there was no attempt to release them becasue
of the
positions of the handles. Read my analysis pop-up by clicking
the
keel-ballast or keel-ballast icon near the top of my reconstruction
page:
http://home.att.net/~JVNautilus/Hunley/reconstruction.html
Michael
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