Minimum crew to operate a sub?

[triple111]

I was having a discussion with some of my friends and the following scenario came up:

You're in a post apocalyptic scenario where you happen to be at a sub base with a fully loaded Los Angeles class moored up. Assuming you can pick from a group of sailors with complete qual cards, what's the minimum crew you could get away with and be able get underway, navigate out of dock, and find an island somewhere warm?

My best estimate is 6, you'd need two in maneuvering, one guy on the ballast control panel and one guy on the bow planes/helm, one to sit in sonar (and move mooring lines etc), and probably one to plot/navigate.

Seems like a lotta work to do but at least no hot bunking