I would just add that things can change DURING the day you are out. If sea sickness is the main concern, take dramamine and/or use the patches or wrist bands regardless of how calm and slick it seems to be when you leave port. Being out 10 miles or more anything can happen and usually does. No fun chumming for the chummer or anyone else on board. So take precautions and don't worry about it so much. A good captain will not take you out is rough seas anyway.

And if you boat on your own, double check iWindsurf or other sites for wave heights before you go out. And if it's too rough, go have breakfast and check again later in the day. Fish are not worth losing your lunch (or your life) over.