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In article ,
says...
Dave, stop trying to change your statements (and stop bottom
posting).
You stated that subs don't use water for ballast.
I posted a few, out of many, sites that state otherwise.

a.
Indeed they do not. They probably use Lead or DU. Neither of those
sites w' the info you posted conclude that subs use water for ballast -
one mentions the key fact, a sub is denser than water. The bouyancy
ballast tanks are then regulated with air to adjust density and float or
sink as required. The water in the bouyancy ballast tanks serve only to
displace the air - and it's ideal as it has the same density as the
water the sub is in (and that alone should tell you, it can never make
the sub sink!)

b.
You are referring to the bouyancy ballast tanks - diphead! That is
*not* "the ballast". Equivalent to a diver's BCD.

c.
Without the ballast at the bottom of a sub (as said, I believe it will
be Lead (or DU for modern war subs)), OR the construction itself -
producing a vessel that is denser than water (mass/volume) - the sub
will not sink!

Just like a diver without a weight belt.

And PS: the only reason subs replace the air with water in the bouyancy
ballast tanks is because they are solid tanks - the water is irrelevant.
(A diver's BCD is not replaced with water, as it's a rubber bag that
simply deflates).

--
Duncan