I don't believe in taking any medications if you don't have to. I would first ask yourself why do you even believe you will have seasickness? Is it just because you are listening to too many outside sources? Too many people assume they will have seasickness. Have you had problems with motion before? Do you have problems even riding in a car, or have you had problems in elevators or on roller coasters? Do you have a medical reason such as inner ear problem? Also comparing a cruise ship to an experience in a small boat on a rocky lake, is not a good comparison.
Today's cruise ships all have stabilizers. There are many remedies to help with motion sickness. If you do have a medical reason for believing you will experience seasickness, then talk to your Doctor about patches, pills, or wrist bands. Other non-medical remedies may be ginger, green apples, and eating crackers or bread.