I have an Akula II and an Ohio class SSNB. I have placed the akula within 500 yards of the Ohio class, and when I try to display the sensor ranges I still get the "computed range = 0" error.

This is happening on all of my passive sonar arrays. What the hell? How am I supposed to make a simple mission where I track and sink the Ohio class? I am totally confused. How do mission writers know how close/far to place units on the map?