When sea conditions are rough, is it better to be on a big or small ship?

No matter what size of cruise ship you travel on, from a safety perspective, you won’t need to worry about rough conditions, as all cruise ships are built with this in mind and feature inbuilt stabilizers to prevent excessive movement. There’s the chance that you’ll feel more movement on a smaller ship, but unless you suffer from sea-sickness, this won’t be an issue.