Alternative to seasickness pills
As a student, I went home to Orkney every holiday. This involved a 2 hour ferry crossing from Scrabster (near Thurso - the north end of the UK rail system).
Although my grandfather insisted this was the roughest piece of water in Europe, I am not convinced. It did get very "bouncy" though!
What does a 19+- year old student do when it gets seriously rough?
1. Go to the cafeteria.
2. buy a coffee, sausage roll and a couple of mutton pies
3. Sit in view of visitors and tourists and eat.
The sight of them running out the room covering their mouths/eyes is so funny you forget to feel bad yourself!