The rack space is extremely small. Smaller than a surface vessel. I can’t remember the exact dimensions but I want to say in the range of 50 centimeters between the mattress and the bunk above you. The racks are in the range of maybe 65-75 cm deep. The mattress is maybe 10cm. All your gear has to fit into the rack, which lifts up on hinges, so maybe you have 6-10 total cm of storage below your rack. I went out of my way to get a mini-disk player when I got shore-leave in japan so I could bring more music with me underway. Also, you are probably sharing this rack space with another sailor because if you are jr. enlisted on a submarine, its almost certain you are hot-racking, which means, someone else is going to crawl into your rack and sleep once you get out of your rack. This serves two function, first you need 24 hour coverage on all watch stations, and, well there isn’t a ton of sunlight anyways so since you’ll need to cover a 24 hour watch regardless, you can get away with fewer racks than you have sailors. Its always hot in the rackspace. Cooling and heating requires pumps. Pumps make noise so you generally just don’t do it. Just a bunch of sweaty sailors and their dirty socks for weeks on end. Yeah maybe you trust them with your life but you sure af better not trust them with your socks. There are also people constantly coming in and coming out of the rack space. So you’ll almost never get undisturbed sleep.

As far as motion… Unless you are doing something like a maneuver, or you are just getting underway or at battle stations, you don’t feel practically any motion on a submarine. You intentionally get below the surface sufficiently to avoid any impacts of wave action, because why wouldn’t you? I would say sea-sickness is far less of an issue on subs for exactly this reason. If there is significant wave action, just go deeper. Now if you are at battle stations or in combat or doing exercises, yes, you’ll 100% feel some motion, and then there are extreme cases like an embt blow, which is going to send bodies flying. But in general, slow and low and trying to create as little motion as possible is the goal with how you are going to practically manage a submarine underway.

As far as sound. Its called the silent service for a reason. Practically every decision is made with a thought about how much sound is this going to make. Every wire run, every pipe, every pump, every circuit; everything is done with a consideration of what impact this is going to have on your profile because the entire point is to be practically invisible to not only other submarines, but surface vessels or anyone else who might be running sonar. Anything humming… thats an unmitigated disaster if you are a submarine and is a practical announcement to any other vessels in your vicinity “Here we are, and here is where we are going”.

So what is it really like? Take a 3 meter x 3 meter garden shed. fit you and 15 of your closest friends onto some of those cheap plastic storage shelves… and spread some corn-nuts or similar smelling items around to get the full authentic experience. Oh and hit everyone in the head with a hammer because I didn’t mention the part about dropping oxygen levels to reduce the risk of fire. So you are always going to be groggy and have a tension headache. But maybe after a couple years you’ll be able to afford college.