On our cruise, we sailed southeast for a couple of days. The wind was out of the southeast at 20 to 30 mph and the ship was cruising at 22 knots. That means that the wind across the decks was between 45 and 50 miles per hour much of the time. We were crossing the Atlantic swells at a right angle and some of them were three meters high. On the way back the swells were lower, but the wind was going the same direction we were. As a result the movement of the air across the deck wasn't enough to mess your hair. It wasn't even enough to keep you cool in the tropics. (We went to 18 degrees N latitude.) In spite of the heavy seas on the way down, I didn't see anybody get seasick. Modern cruise ships have stablizing fins and don't rock very much. There is some mild pitching, but on ships about 900 feet long, it's not a real problem. In the Carribean, sometimes you couldn't tell you were moving unless you looked out the window.
Howard