I have never been seasick to the point of barfing, but I've felt pretty bad a few times. On occasion I will use sturgeron. My wife always gets seasick on the first couple of days of
passage offshore, and the only thing that works for her is scopolamine patches.
The most seasick I have ever been happened a couple of months before we started our
circumnavigation. I had announced to my friends that I was sailing with my
family around the world in a few months. Then I did an overnight sail to the
Bahamas and was really seasick. But the problem wasn't the seasickness as much as the fact that I had quit my job, purchased a
new boat, announced my plans to my friends, and I was as sick as a dog. I dreaded starting the
circumnavigation if it was going to be that horrible. Fortunately, that was the first and last time it happened.