I, too, get seasick looking at a ship . . . I used meclizine for two years, starting 36 hours before getting on the boat and taking double the dose (under a doctor's recommendation). Still, I get horribly sick if the seas go about about 3'. However, that is
me, and I am horribly sensitive.
If you wish to go the prescription route, try
Scopolamine - Wikipedia, the free encyclopedia. It is prescription, and I used it on land to discover side effects before trying to dive with it. It works PD well for me, but I still have urped.
YMMV.
PS - go to the pharmacist and ask for the "big bottle" of meclizine. You can get a bottle of 100 tablets for way less than the over-the-counter 24-in-a-pack Bonine.