I have found nothing is failsafe. I do blue water sailing and when it really gets rough I usually have a bout of Sea sickness for about 24 hours. I tried Scopolomine and its terrible. Had trouble focusing on my charts or reading etc. and when it really got rough during a storm I got sick.
Best advice is stay busy on board and to spend as much time as possible on a boat in motion prior to going out. Once the system adjusts you're home free.