I’m not Navy but I’ve gotten these impressions of Sub life from various sources:
1) A Nuke sub has 2 alternating crews, Blue and Gold.
2) They leave port and submerge for 60 day tours.
3) Each crewman cross trains to perform every task on the boat. This would put someone pregnant at risk to get more of a dose than someone in her condition should.
As general information, most emergency personnel transfers from a submarine are done via a helo and a harness from the fairwater planes or maybe the missile deck on a ballistic missile submarine. Of course it wouldn’t be done this way if the medical condition of the transferee prevents this method. Bringing a submarine into port to transfer personnel means there is an extended hole in the sub’s mission and it is highly unlikely another resource is available to take its place.
Only ballistic missile submarines have two crews. Fast attack submarines have one crew. Crewman do not cross train to do every job on a sub. A sonarman is a sonarman and a cook is a cook. Submarine personnel are required to have a basic understanding of the submarine and all are required to do some tasks like rig the sub for dive. Most non-nucs also all are trained as helmsman and on the dive planes.