Hi Martijn,
What race are you sailing?, and you sailing solo?
I carry a dry-sack in which I carry food, water, mobile phone, tools, and some money.
If you wear a drysuit try not to drink so much or you will end up with a "wet" suit. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />
Also studying the route and carrying a GPS for navigation is a good idea.