Well I like the idea of combining Tactical and Navigation because if you were fighting then you would not be plotting a long range course and vice versa. Most of the time tactical would not be doing much at all except some scanning, assuming the ship was not a combat vessel. I would like a term that could encompass both functions.
I agree that Tactical and Security should be separate functions. I have no idea why anyone would combine them. If you have intruders then you are likely in a dangerous situation and that would be the time that you would need your tactical officier on the bridge. Besides the fact that they both involve weapons there is no connection between the two of those.
I can see your point about the communications station though. I'll think about that one.
thanks for the feed back