LTJG Amber Cowan and LTJG Jennifer Nonnan are assigned to the Blue crew of the ballistic missile submarine USS Maine (SSBN 741).

I swear that was Robert De Niro shaking their hands.

It looks like him, but it's not.

I thought female submariners were uncommon because of the low privacy onboard submarines.

SSBN's are nuclear ballistic missile subs. They are giant and offer plenty of room for the crew.