Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

That would depend on how far it surfaced. Did it blow all ballast or is
it just barely surfaced?

Steve


It can't blow enough ballast to put the keel on the surface. My point is merely
that if the depth is measured between the surface and the keel, (and I have no
reason to doubt that it is) there could never be a "zero" reading.