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Re: [PSUBS-MAILIST] Hunley ballast



Hi Cliff.
 
If they pumped water from the (open top and open to the hull interior) ballast tanks into the dry part of the hull or another container within the hull, it would be the same as letting the water sit right in the open top ballast tanks. The volume taken up by the
 
uncompressable water would be the same. The only effect of your suggestion would possibly be instability caused by not having the water weight in the proper placement for trim fore and aft in the sub.
 
You are correct Cliff about them not knowing about dive tables back then. But it MAY be possible they could have suffered from decompression sickness before they asphyxiated. In the historical records as well as the film, it shows the Hunley crew sitting on the
 
bottom until their lungs could no longer take it and they accended. They sat down there for hours. If you stayed that long using scuba you would definately be over your no decompression time limit. The only thing that would make a difference here is that the Hunley
 
crew were not breathing or surrounded by a HIGHLY pressurized atmosphere. Also they were rebreathing stale air and not fresh compressed air. This may have made a difference as well. Not being a barometric chamber expert or gas toxicologist I cannot say how long
 
they could have lasted sitting on the bottom or whether they would have definately suffered from decompression sickness before they ran out of air and died. That is an interesting question, and one best answered by the two expert professions above.
 
Kindest Regards,
 
Bill Akins.
 
 
 
 
----- Original Message -----
Sent: Thursday, May 19, 2005 10:10 AM
Subject: [PSUBS-MAILIST] Hunley ballast

I haven?t had time to do much research on the Hunley but a thought crossed my mind that might help.  If they could pump water out of the ballast tanks, could they pump water into the main compartment or some other type of reservoir inside the sub?  I think I remember somebody mentioning a bellows type of pump and I would think it could handle back and forward pressures similar to todays hand bilge pumps.  If it could pump against another 5 or 6 pounds of pressure, this would enable them to get down a few more feet with minimal increase in the cabin pressure.  Don?t know the overall weight and displacement of the sub, but maybe a few additional feet would get them over the positive hump.

 

Additionally, I don?t think they were too familiar with dive tables back then (lol).  In any event, being unable to use the snorckel suggests that they didn?t want to release pressurized air from the cabin while submerged.  That limits them to the air supply that they had when they submerged.  With a crew of 8 (?), I think they would have asphyxiated before suffering from decompression problems.

 

Best Regards,

Cliff