[Rockin Robbins]

Pretty awesome! Do you know what year that circular slide rule of yours came from? Do we know for sure that nothing like that was used during the war? I know they did bearing rate plots and derived enemy relative course and speed. They must have had a similar tool but I bet it was a straight slide rule (a slip-stick), not a circular one.

This is important because bearing rate charts were extensively used by the real submarines and we don't use them at all.