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In a message dated 5/19/2010 4:12:10 A.M. Pacific Daylight Time,
laland@artematrix.org writes:
"In the case of implosion problems, Hi Jens. I was thinking of "over pressure " in a ballast tank if the water
exit holes were too small and the ascent rate became uncontrolled. As for
"imploding" the ballast tanks, I think that would be difficult in one of
our subs because as they are designed, the sub doesn't sink until the ballast
tanks are fully flooded.
As I understand the dive procedure, the pilot dumps the air and the
ballast tanks fill with water. As the sub settles the variable ballast tank is
adjusted to attain neutral buoyancy at just below the surface. The sub is now
completely submerged and free to move up or down in the water column. Some
further adjustment may be needed for changes in temperature or salinity but
these are small changes in the "hard" VBT.
Once the dive is done, the pilot "motors" the sub back to the surface and
then blows the ballast to raise the hatch out of the water. This requires HP air
from scuba tanks or possibly a positive displacement "blower" in a very large
vessel but the pressure needed isn't a lot because the sub is already at or near
the surface.
I've calculated a rough estimate using the two 80 cu. ft. scuba
tanks on board and the 145 cu. ft. reserve tank to give me a minimum of 4
complete ballast tank fills at 10 feet of depth. I also plan to have two
emergency tanks inside at 40 cu. ft. each with regulators attached for the
unlikely event I have to flood the sub and climb out. ( man, I hope that never
happens ! )
Frank D.
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