Black Prince is the oldest and the smallest of the Fred Olsen fleet but she was built for the north Sea and all of the rotten weather that you can get there. Expect some movement in the Bay but she'll ride it ok. Last time I came through it the Bay was like a mill pond and that wasn't very long ago. If you really have trouble with sea sickness then take the tablets or have an injection when you feel queasy both of these are available on board but if you just think you might be unwell just wait because you may not be affected. ...regards....Nei.
I was also really worried about this when we went to Caribbean in Nov 2006. I'm a really sickly traveller usually and went prepared for the worst. We did have a REALLY rough day and I did exactly what I'd read it all the books. I stayed on deck and looked out to sea all the time - didn't read and didn't put my head down much. My partner (an old sea dog) went to cabin and emerged nauseous! One side of the deck was closed as the waves were actually sweeping over the sides but I actually enjoyed it - quite exciting.
Don't bother buying anti sickness drugs on board, I was told that G.P's will prescribe and they cost a lot less than ships's doctors.
Last year I took Sturgeron? from the chemist and the wrist bands with me just in case, used both on rough day on the Med, the bands are £3.99 in Sainsburys, so worth taking with you. they work on the accupressure points on your wrists. Or there are lots of natural/herbal remedies. I would recommend taking something with you as much cheaper than visiting the Doc on boar.