if you're ever in stockholm, there's a ship that you can make a reservation for called viking lines. it's completely free (i know, i lucked out). you get your own cozy bedroom that's with a complete washroom (and they even throw in a towel for u). it's amazing. the ship has everything u need: disco, casino, buffets, bars, duty-free shopping etc.
this ship also goes to talinn (estonia) or helsinki (finland). they all got reserved fast, so i settled for a fishing town called mariehamn.
there's two groups of people on this ship: geriatric retirees and twenty-somethings who want to get loaded. this is a party boat. unfortunately, instead of dancing with the retirees and young people at the disco all nite..i ended up taking a power nap that lasted 8hours...i missed it all:(
..but i did see finland.
looking out from the deck at 4am & only seeing blackness