This story happened a few years when I spend an exchange semester in Helsinki in Finland (I’m from Germany). On one weekend a group of friends and me, around 12 people, planned to go on a weekend trip to Stockholm. We were a group of international students from Spain, France, Italy, Germany, and Norway and all wanted to enjoy our time abroad and not spend too much thought on studying during this weekend. There are daily overnight ferries from Helsinki to many other cities on the Baltic sea, so we decided to take such a cruise and this is where the story takes place.
We boarded the ferry in the evening. As the whole journey takes around 14 hours, you have to spend quite some time on it. Therefore, these ferries are more like cruise ships. All passengers get a cabin and there is a wide range of facilities like shops, restaurants, and a nightclub. As students without much money, we of course booked the cheapest, hostel-style cabins which are shared by 4 people (with two bunk beds). Soon after finding our cabins, we started to explore the ship (and very soon after found the first drinks in the onboard duty-free shop).