I was in Antarctica last January.
You never know. Our cruise south was smooth. "These waves are pathetic," said a crew member. On the way back, it was rougher. Rougher than my Galapagos cruise, for sure. I didn't have a problem, but the dining room was noticeably emptier. There were rails lining all hallways that you could grab, and I did my share of lurching when the ship rocked. The housekeeping staff thoughtfully draped sick bags over them at 3-foot intervals, but I never saw anyone use one.
I did, however, hear some stories from the crew about much rougher crossings. In one case, passengers were ordered not to leave their cabins. "We brought them tea and sandwiches."
The lower down your room, the less rock & roll there is.
Our ship was a 100-passenger one, with stabilizers.
Edited to add: I brought dramamine & wristbands with me, but never used them. A lot of passengers had ear patches.