Re: bunking - that's largely untrue. The majority of crew members on board do get their own bunk. But there aren't enough bunks for everyone, so people have to "hot rack" (aka, share). On my boat, this typically meant 3 people sharing 2 beds - if three people that share the same watchstation are hot-racking, at least one of them has to be on watch at any given time, so the other two have a bed if they need it.
Also, a decent number (maybe 10-ish) of the beds/racks tend to be in the torpedo room. Those guys just need to be comfortable sleeping next to big underwater bombs. :)
It's changed a bit, but the thing that made everyone fatigued is that your body is used to a 24-hour day, but your work day was an 18-hour day: 3 sections of 6 hour watches.