[Whyte]

I had the opportunity to visit a Russian sub in San Diego. And holy moly, but it was a claustrophobic experience. The crew was almost hundred, altogether, hot-bunking in small bunk beds, slotted into the walls with three beds stacked together, the lowest almost on the floor. I think there was only two toilets, too. Cramped corridors, bulkheads with circular openings just barely big enough for me to duck through without needing to try and slide through head first. So yeah, for very limited-space configuration warship, I could easily see three bunks in 2 m2, and those bunks hot-bunked (shared by 2 or even 3 crew-members, so that there is always someone sleeping there). So you could fit 6 - 9 people in 2 m2, and given that the ceiling wasn't too high either, it comes to less than 1 m3 per person. Add the narrow corridor in the middle and you are still well below 1.5 m3 per person.