Update:
I went on a cruise for a week last month. Despite my vertigo history, I didn't get seasick :hoorah:. True that the first few hours, everything seems to be rocking, but nothing a bonamine can't take care of. I took the pill twice the first day and the others just before I sleep because the rocking feels weird when lying down. The other days, I got used to the motion already. After the cruise there is just a weird sensation of still rocking even when in land already but it goes away.
Btw, I recommend going on a cruise! It was fantastic, especially if you love to eat, eat, eat, and drink.