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[PSUBS-MAILIST] Re: [CSS H L HUNLEY] Re: Hunley ambient? and ballast and dive plane operation.



Hi Forum.
 
Although I sent my questions to an unofficial Hunley site thinking it was the official one, I received a response from someone at that non offical Hunley site. Here it is below.
 
I will contact the official Hunley site now that I have the correct URL and will post their response if and when they respond.
 
Kindest Regards,
 
Bill Akins.
----- 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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