The key is use whatever you will use before getting seasick -- would recommend even starting during the sleep aboard -- there is a little motion just at the dock which helps acclimate and minimize the seasickness your first day out -- but if really prone to car-sickness may still have trouble the first few days. Have always recommended for crew and used myself the non-drowsy formula dramamine -- nonprescription -- works for us and no visual difficulties or possible urinary retention sometimes seen with scopolamine patch.
There is no person that has not/cannot have seasickness with big enough seas...