Thank you. I have felt nauseous on a boat before but only once when I was on a smaller one below deck. If you can get up on the deck and see the horizon it can help. Once your feeling sick it is hard though. I've been on a few boats in a gale force wind and I was once on a cruse ship in Alaska that got blown around a lot. Lucky for me it was at night and I slept through most of it and it calmed down the next day.
My white knuckle sailing days are over though.