Agree with this- what kind of “cruise”? We did the one day out of Bergen deal-- you board a boat in the harbor, they take you out, they bring you back. It’s a small boat (maybe 50 people capacity) and it didn’t have the rocking motion that I know many people find nauseating. Just a smooth ride.
I think a longer cruise has the potential for seasickness- you’re further out (ours hugged the shoreline and then circled some of the close by glacier and icy mounds but the water was perfectly still) and you’re far from land for some of the trip.
I don’t think the day cruises sail if the weather is bad…