I treated the waves much in the same way that I treat turbulence on a plane: I kind of braced myself, and figured on waiting it out. But unlike turbulence (which typically is short lived), traveling over rough waters can last hours on end. So I found myself in a constant state of waiting for the other shoe to drop.
We were warned by the captain that we might be in for some rough travel, and he advised folks who might be prone to motion sickness to take some Dramamine. I’ve had a bad history of seasickness – most notably when I was traveling to Cozumel a few years ago. I made the mistake of trying to video our ferry ride, and watching the camera viewscreen while we were moving more or less did me in. I felt nauseous for a few hours afterwards, and it was a terrible feeling that took a long time to get rid of. It wasn’t something I really was wanting to experience again.