Ok, Robert, I get what you mean.
1st) A bulkhead by definition is a steel or wooden wall transverse or longigitudial to the ship's fore and aft axis and always at abt. right agle to the decks.
Transverse bulkheads for and aft of the control room are both convex (viewed from inside the control room), the floor of the control room was concave to better withstand the pressures of the dive tanks below. A flat floor would implode more easily. So, a transverse cut through the control room would look somewhat like a shape of an american type football. Floor gratings created level standing space not occupied by machinery etc. RB