This is video/stories from the Viking Sky's Cruise were engines failed during rough waters. Hundreds of passengers aboard the ship had to be airlifted one at a time after the ship left Norway for a 12-day Northern Lights cruise and encountered dangerous weather.
I'm a huge cruise fan, I think they are amazing trips. Everything you need is on the boat, you don't have to worry about driving anywhere. They have entertainment, casinos, bars and so much more. Plus, everything's paid for like the food once you get on, obviously you can spend more once on the ship but you don't have to. I actually just booked a cruise today for later this year.
I always hear people say they would never do one because of things like this or because you'll feel trapped once on the ship. Here's the thing, you don't know unless you give it a try and no matter what you do in life there are risks attached, driving to work/school everyday is a risk. Stop worrying about the worst case scenario and just enjoy yourself.