Everyone reacts differently, so it is really hard to say. But in general, our sunset cruises that stay on the bay are pretty mild, and most people have no trouble. For our all-day sails onto the ocean, things are more unpredictable. If you have a tendency to get sick (sea, air, car), it might be a good idea to take precautions. There are many things that can help, from Dramamine to patches, to ginger. If in doubt, talk to your doctor.
Also, if you do start to feel sick, let a crew member know immediately. There is no need to be embarrassed. Even the most seasoned sailors sometimes get sick, and we know some tricks that can help. If worse comes to worse, we can help you get to a safe place to feed the fishes. 😉