I always chime in on these posts. First like other posters have said - talk to your doctor first. Second - I am the kind of person that gets sick in the car if you go in reverse too fast so I'm EXTREMELY sensitive to motion sickness. Weather can play a large part of motion sickness along with the speed the ship is sailing.
I have to have the patch. I've sailed 3 times - once without it and twice with it. And have been on smaller ships many times over the years as I live in a coastal area. Over the counter stuff doesn't help me at all. I've done sea bands, ginger, bonine and dramamine. Not any of them helped. But the patch? A miracle.
I will warn you though, it still is not foolproof. We sailed Feb 2015 to Grand Caymans on the Wonder. It was extremely windy and the ship was really moving to get out of weather. Even with the patch I threw up. The boat was pitching so bad that you couldn't walk a straight line down the hall way. This is rare though and common in Feb from what I have read. Fortunately, it was only that bad on one morning of our cruise.
You will feel the boat move. Period. How much really depends on weather, wind speed and boat speed. It will be less on a newer, larger ship but you will feel it.
That being said, there are side effects from the patch that some people can not tolerate. I can as they are very minor compared to laying in bed for half the cruise like I did on the first one.
I do get slightly blurred vision. This is due to the patch slightly dilating your eyes. I do get dry mouth. I keep a bottle of water with me and it combats that. Other than that, if you use a patch, I would recommend keeping it on a day after you cruise. Your sea legs will still be on and the day after can really hit you in the gut as your body readjusts to land.
I got sick the day after I got home because I took my patch off too soon after the cruise.
Go talk to your doctor and I would try various methods of motion sickness meds/remedies in advance. There are things that work so don't let it stop you.
I'm cruising again in about 45 days so even though last year was rough, I won't stop cruising.