I've only been on a cruise ship once as a passenger on an older Carnival ship for my honeymoon. But here are my observations:
1. The typical passenger cabins are on the small side, and the bathrooms are truly tiny. It's hard to shower without bumping into the walls or the curtain.
2. Much of the time, the crew is invisible except for service staff. The captain would occasionally address the passengers at some of the special events that were held in a theater towards the bow of the ship. Most of the time, I presume the captain was at the bridge or in his room.
3. The food is one thing you really notice on a cruise ship. Carnival is one of the less expensive cruise lines, and the food was comparable in quality and presentation to the food served at the Ritz-Carlton. (Which is where my wife and I had stayed just before going on the cruise.) When I ordered lox and bagels, the lox looked like it had been prepared by a sushi chef. There were three restaurants and a snack bar on the lido deck aboard our ship. Most items, except for booze and soda, are included in the ticket price, even if you want second helpings of lobster.
4. The higher-up staff member that the passengers see most often is probably the cruise director. His job includes conducting presentations about the shore excursions, which are essentially pre-packaged tours conducted by outside contractors. The one on our trip was a rather comical fellow. His briefing on what to do when we returned to our port of departure included stating that all Cuban cigars purchased in Mexico should be turned over to him so he could smoke them all before reaching port.
5. The ship we were on was powered by eight large diesel engines. Being a gearhead, I tried to persuade the staff to let me tour the engine room, but they refused.
6. Ship decor normally looks like an upscale hotel, but the ship has a large number of curiously industrial-looking signs about safety information, muster stations, and the like.
7. This one may be rather important since you have the ship sinking. If it is likely that everyone must abandon ship, they will announce over the PA system for everyone to report to their muster station. Each cabin will have life jackets, and each life jacket is marked with a letter. The ship has signs all over with letters, corresponding to the letters on the life jackets, with arrows and signs that say "muster station." Passengers are supposed to go to the muster station indicated on the life jacket.
8. Lifeboats on a modern cruise ship are covered with a shell that I believe to be fiberglass. They look like miniature submarines. You can find a clear picture of one
here.
This page also has a few pictures of one.