Posting an answer to something I know nothing about is illogical.

Rick

I don't dispute that- ergo the disclaimer.
But if the depth is measured from the keel and there is a depth indicator on
the sub it will never read zero. Is that somehow incorrect? That was why I
postulated *if* a depth guage read zero at the surface the reading would have
to be from the normally ballasted waterline. Since it apparently does not read
zero, that theory doesn't fly. Freely admitted.