Agree with captdennyj on all points.

In terms of meds, Cinnarazine is always my recomendation. I've seen it work wonders for so many former crew-mates. We had a particularly bad Sydney-Hobart race back in 2010...by the end of which, everyone on the team (including the 'iron-stomached' Aussies) was a convert to this magic potion! Its generally branded as Stugeron in the UK...which can make you a bit drowsy, especially at 3am on night-watch! But if you talk to a doctor they can prescribe a non-drowsy alternative. My wife is a doc and previously had some sea-sickness issues...but not anymore. Problem solved!