Strange route; but I suppose it's not so much a ferry as a jolly :-)
I echo the "days off" sentiments and suggest that the weather should be the driving factor. At least your plan has some slack to allow for that.
Your equipment list should include a battery-powered GPS (with local database) and a handheld radio as well as the satphone suggested. Make sure you have a very large pack of the appropriate batteries for all three! And don't forget the medicinal brandy in the first aid kit.