Yes, it happens sometimes. If you know that you are susceptible to motion sickness, we can give you plenty of tips on getting around this. Meclazine, scop patches, wrist bands, ginger… different remedies work for different people. The most effective sea-sickness cure is getting on the helm. Seriously!
For some people, it’s smart to stay up on deck for the first day; after that, we find that the vast majority of people acclimatise and are just fine. If you get sick on planes, trains, automobiles and said duckponds… it might not be your best choice.